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Sample records for jurassic ligurian tethys

  1. Crustal structure of the SW Iberian passive margin: The westernmost remnant of the Ligurian Tethys?

    Science.gov (United States)

    Ramos, A.; Fernández, O.; Torne, M.; Sánchez de la Muela, A.; Muñoz, J. A.; Terrinha, P.; Manatschal, G.; Salas, M. C.

    2017-05-01

    At present, the SW Iberian margin is located along the convergent Iberia-Nubia plate boundary. In Mesozoic times, the margin was located at the triple junction of the Ligurian Tethys, Central Atlantic and Northern Atlantic. The characterization of its crustal structure has allowed us to propose a configuration for this triple junction and to determine the role that this transform margin played within the plate kinematic system. In this paper we present an integrated study based on the interpretation of a 2D regional multichannel seismic survey consisting of 58 profiles, tied with onshore geology and exploratory wells, and on gravimetric modeling performed over four NW-SE trending profiles. Integrated interpretation of MCS data combined with 2D gravity modeling reveals a complex pattern in the southward crustal thinning of SW Iberia and supports the possible presence of oceanic crust under the Gulf of Cadiz. The tapering of Iberian crust is characterized by steps with rapid changes in the thickness of the crust, and thinning to Bank. Margin inversion and the pre-existing extensional crustal structure are responsible for the areal distribution and amplitude of the prominent positive gravity anomaly observed in the Gulf of Cadiz.

  2. Late Jurassic blueschist facies pebbles from the Western Carpathian orogenic wedge and paleostructural implications for Western Tethys evolution

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    Dal Piaz, Giorgio V.; Martin, Silvana; Villa, Igor M.; Gosso, Guido; Marschalko, Robert

    1995-08-01

    In spite of the absence of ophiolitic slices at the surface, some traces of the lost Tethys ocean are recorded along the Pieniny Klippen Belt (PKB), a narrow décollement thrust system sutured at the transpressive boundary between the Outer and Inner Carpathians. The enigmatic precollisional evolution of Western Carpathians can be deciphered from some late Albian to Campanian flysch conglomerates which display chrome spinel grains, ophiolitic detritus and pebbles of blueschist facies tholeiitic metabasalts yielding a 40Ar/39Ar plateau age of 155.4+/-0.6 Ma. Other detrital components are represented by extrabasinal pebbles of limestones, arc volcanics, and igneous to metamorphic basement rocks from southern sources. Our results suggest a markedly northward extension of the sublongitudinal Triassic Vardar (Meliata) Ocean and its subduction since the late Middle Jurassic, supposedly balanced westward by coeval spreading in the Ligurian-Piedmont basin of the Apennine-Western Alpine Tethys. A lateral kinematic connection between these diachronous and roughly parallel Tethys branches was provided on the north by a left-lateral east-west trending shear zone running from the Swiss-Austrian Penninic domain to the Northern Carpathians. This reconstruction replaces the classic model of two paired North Penninic and South Penninic oceanic basins and eastern homologues with the Briançonnais-Hochstegen and Czorstin microcontinents in between. The Late Jurassic-Early Cretaceous evolution of the Carpathian active margin was characterized by subduction metamorphism and accretion of a wide orogenic wedge; in this time, the shallowing to deeply subsiding basins inferred from facies analyses on the sedimentary units of the PKB were likely floored by individual sections of the growing wedge. Later, some exhuming blueschist ophiolitic units of the wedge were uplifted to the surface and functioned in the Albian-Campanian as an ``exotic ridge'' supplying clasts to the forearc basin

  3. Jurassic carbonate microfacies, sea-level changes and the Toarcian anoxic event in the Tethys Himalaya (South Tibet)

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    Han, Zhong; Hu, Xiumian; Garzanti, Eduardo

    2016-04-01

    Detailed microfacies analysis of carbonate rocks from the Tingri and Nyalam areas of South Tibet allowed us to reconstruct the evolution of sedimentary environments during the Early to Middle Jurassic. Based on texture, sedimentary structure, grain composition and fossil content of about 500 thin sections, 17 microfacies overall were identified, and three evolutionary stages were defined. Stage 1 (Rhaetian?-lower Sinemurian Zhamure Formation) was characterized by siliciclastic and mixed siliciclastic-carbonate sedimentation on a barrier shore environment, stage 2 (upper Sinemurian-Pliensbachian Pupuga Formation) by high-energy grainstones with rich benthic faunas thriving on a carbonate platform, and stage 3 (Toarcian-lower Bajocian Nieniexiongla Formation) by low-energy mudstones intercalated with frequent storm layers on a carbonate ramp. Besides, Carbon isotope analyses (δ13Ccarb and δ13Corg) were performed on the late Pliensbachian-early Toarcian interval, and the organic matter recorded a pronounced stepped negative excursion -4.5‰ corresponding to characteristics of the early Toarcian oceanic anoxic event globally, which began just below the stage 2-stage 3 facies shifting boundary. The comparison between the Tethys Himalaya (South Tibet) and the tropical/subtropical zones of the Western Tethys and Panthalassa was carried out to discuss the factors controlling sedimentary evolution. The change from stage 1 to stage 2 was possibly induced by sea-level rise, when the Tibetan Tethys Himalaya was located at tropical/subtropical latitudes in suitable climatic and ecological conditions for carbonate sedimentation. The abrupt change from stage 2 to stage 3 is interpreted as a consequence of the early Toarcian oceanic anoxic event, accompanied by obvious carbon-isotope negative excursion and sea-level rise. The failed recovery from the carbonate crisis in the early Bajocian, with continuing deposition on a low-energy carbonate ramp, is ascribed to the tectonic

  4. Triassic-Jurassic organic carbon isotope stratigraphy of key sections in the western Tethys realm (Austria)

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    Ruhl, Micha; Kürschner, Wolfram M.; Krystyn, Leopold

    2009-05-01

    The late Triassic period is recognized as one of the five major mass extinctions in the fossil record. All these important intervals in earth history are associated with excursions in C-isotope records thought to have been caused by perturbations in the global carbon cycle. The nature and causes of C-isotopic events across the Triassic-Jurassic (T-J) transition however, are poorly understood. We present several new high resolution organic C-isotope records from the Eiberg Basin, Austria, including the proposed Global boundary Stratotype Section and Point (GSSP) for the base of the Jurassic. The Triassic-Jurassic boundary interval in these records is characterized by the initial and main negative organic carbon isotope excursions (CIE) of up to 8‰. The initial and main CIEs are biostratigraphically constrained by first and last occurrences of boundary defining macro- and microfossils (e.g. ammonites). High resolution C-isotope records appear to be an excellent correlation proxy for this period in the Eiberg Basin. Pyrolysis analysis demonstrates increased Hydrogen Index (HI) values for organic matter coinciding with the initial CIE. Terrestrial organic matter influx and mass occurrences of green algae remains may have influenced the C-isotope composition of the sedimentary organic matter. This may have contributed to the extreme amplitude of the initial CIE in the Eiberg Basin.

  5. Possible markers of the Jurassic/Cretaceous boundary in the Mediterranean Tethys: A review and state of art

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    Jozef Michalík

    2011-10-01

    Full Text Available During the last decades, several integrated studies of Tethyan Jurassic/Cretaceous boundary sections from different countries were published with the objective to indicate problems for the selection of biological, chemical or physical markers suitable for identification of the Jurassic/Cretaceous boundary – the only system boundary within the Phanerozoic still not fixed by GSSP. Drawing the boundary between the Jurassic and Cretaceous systems is a matter of global scale discussions. The problem of proposing possible J/K boundary stratotypes results from lack of a global index fossils, global sea level drop, paleogeographic changes causing development of isolated facies areas, as well as from the effect of Late Cimmerian Orogeny. This contribution summarizes and comments data on J/K boundary interval obtained from several important Tethyan sections and shows still existing problems and discrepancies in its determination.

  6. JURASSIC PALEOGEOGRAPHY OF THE PIENINY AND OUTER CARPATHIAN BASINS

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    JAN GOLONKA

    2004-03-01

    Full Text Available The Jurassic history of the Pieniny/Outer Carpathian basins reflects the evolution of the Circum-Tethyan area, especially its Alpine Tethys part. The Alpine Tethys that is Ligurian, Penninic Oceans and Pieniny/Magura Basin constitute the extension of the Central Atlantic system. The synrift stage lasted in the Pieniny/Magura Basin from late Early Jurassic to Tithonian (the Magura Unit constitutes the southernmost part of the Outer Flysch Carpathians. The Pieniny rift opened during Pliensbachian – Aalenian. The central Atlantic and Alpine Tethys went into a drifting stage during the Middle Jurassic. The Late Jurassic (Oxfordian-Kimmeridgian history of the Pieniny/Magura Basin reflects strongest facial differentiation within sedimentary basin where mixed siliceous-carbonate sedimentation took place. Greatest deepening effect is indicated by widespread Oxfordian radiolarites, which occur in the all basinal successions, whereas the shallowest zone is completely devoid of siliceous intercalations at that time (sedimentation from Ammonitico Rosso facies up to coral reef limestone. The southern part of the North European Platform, north from the Pieniny/Magura realm, started to be rifted during Late Jurassic time and Silesian Basin in the Outer Western Carpathians and Sinaia Basin in the Eastern Carpathians, with black, mainly redeposited marls have been created. The outer sub-basins were differentiated during the latest (Hauterivian-Barremian phase of basinal development. The connection of Silesian Basin with Sinaia and Southern Carpathian Severin areas suggests the NW-SE direction of the basinal axis while the orientation of the Pieniny Klippen Belt/Magura Basin was SW-NE so, two Outer Carpathian perpendicular directions are possible within the basins. Major reorganization happened during the Tithonian-Berriasian time. It was reflected by both paleoceanographical and paleoclimatical changes. The Neo-Cimmerian tectonic events as well as main phase

  7. The Productive Ligurian Pool

    CERN Document Server

    Casella, E; Couvelard, X; Caldeira, R M A

    2011-01-01

    In contrast with the behavior of the eddies in the open-ocean, the sub-mesoscale eddies generated in the constricted Ligurian Basin (NW Mediterranean), are unproductive but their combined effect, arranged in a rim-like fashion, contributes to the containment of a Productive Ligurian Pool (PLP). Data de- rived from MODIS satellite sensor showed persistent higher chlorophyll con- centrations in the centre of the basin, concurrent with high EKE values in its surroundings, derived from AVISO altimetry merged products. This sug- gested that this 'productive pool' is maintained by the intense (sub)mesoscale eddy activity in the rim. Numerical realistic experiments, using a Regional Ocean Model System, forced by MERCATOR and by a high-resolution COSMO- l7 atmospheric model, also showed that most of the sub-mesoscale eddies, during 2009 and 2010, are concentrated in the rim surrounding the basin, contributing to the formation of a basin-scale cyclonic gyre. We hypothesized that the interaction between eddies in the r...

  8. Cretaceous gastropods: contrasts between tethys and the temperate provinces.

    Science.gov (United States)

    Sohl, N.F.

    1987-01-01

    During the Cretaceous Period, gastropod faunas show considerable differences in their evolution between the Tethyan Realm (tropical) and the Temperate Realms to the north and south. Like Holocene faunas, prosobranch, gastropods constitute the dominant part of Cretaceous marine snail faunas. Entomotaeneata and opisthobranchs usually form all of the remainder. In Tethyan faunas the Archaeogastropoda form a consistent high proportion of total taxa but less than the Mesogastropoda throughout the period. In contrast, the Temperate faunas beginning in Albian times show a decline in percentages of archaeogastropod taxa and a significant increase in the Neogastropoda, until they constitute over 50 percent of the taxa in some faunas. The neogastropods never attain high diversity in the Cretaceous of the Tethyan Realm and are judged to be of Temperate Realm origin. Cretaceous Tethyan gastropod faunas are closely allied to those of the 'corallien facies' of the Jurassic and begin the period evolutionarily mature and well diversified. Three categories of Tethyan gastropods are analyzed. The first group consists of those of Jurassic ancestry. The second group orginates mainly during the Barremian and Aptian, reaches a climax in diversification during middle Cretaceous time, and usually declines during the latest Cretaceous. The third group originates late in the Cretaceous and consists of taxa that manage to either survive the Cretaceous-Tertiary crisis or give rise to forms of prominence among Tertiary warm water faunas. Temperate Realm gastropod faunas are less diverse than those of Tethys during the Early Cretaceous. They show a steady increase in diversity, primarily among the Mesogastropoda and Neogastropoda. This trend culminates in latest Cretaceous times when the gastropod assemblages of the clastic provinces of the inner shelf contain an abundance of taxa outstripping that of any other part of the Cretaceous of either realm. Extinction at the Cretaceous

  9. Trachyteuthis covacevichi n. sp., a Late Jurassic Palaeopacific coleoid cephalopod

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    D. Fuchs

    2008-02-01

    Full Text Available A new early Oxfordian coleoid cephalopod, Trachyteuthis covacevichi n. sp., is described from northern Chile. It represents the first Late Jurassic Palaeopacific vampyropod and thus considerably extends the palaeogeographic distribution of trachyteuthids. In general, Tr. covacevichi n. sp. possesses a gladius typical for the genus, but wider than in other species. Similarities between Tr. covacevichi n. sp., Tr. palmeri from the Oxfordian of Cuba and Tr. sp. from the Kimmeridgian of Europe confirm a Caribbean Seaway between the Tethys and the Palaeopacific during Late Jurassic times. Morphologically, the wide gladius of Tr. covacevichi n. sp. supports a close phylogenetic relationship between Teudopsis and Trachyteuthis. doi:10.1002/mmng.200700012

  10. Distribution patterns of the Jurassic ostreids (Bivalvia) from Tanggula of China

    Institute of Scientific and Technical Information of China (English)

    沙金庚

    2001-01-01

    Distribution of the Jurassic ostreids (Bivalvia) from Tanggula area of China includes three patterns, which are (1) Tethys: containing Liostrea birmanica and Eligmus rollandi, (2) western Europe and northern Tethys: consisting of Gryphaea (Bilobissa) bilobata; and (3) Global: composed of Actinostreon gregareum and Nanogyra nana. However, they are all limited between palaeolatidudes 60° South and North. Actinostreon gregareum originated in the Sinemurian of northern Chile and it entered Kenya and Madagascar in the Toarcian, but there is no reliable Si-nemurian-Toarcian A. gregareum fossil record in continental margins between Chile and Kenya and Madagascar. Such distribution patterns and dispersal processes have demonstrated that (1) during the Jurassic all seas and oceans were connected to each other; (2) the Tethys and the western European epicontinental seas did produce some endemic taxa; (3) the distribution of these ostreids was most likely controlled by latitudes and creature ecology; and (4) A, gr

  11. Jurassic sedimentary evolution of southern Junggar Basin:Implication for palaeoclimate changes in northern Xinjiang Uygur Autonomous Region, China

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    Shun-Li Li; Xing-He Yu; Cheng-Peng Tan; Ronald Steel

    2014-01-01

    Junggar Basin, located in northern Xinjiang, presents continuous and multi-kilometer-thick strata of the Jurassic deposits. The Jurassic was entirely terrestrial lfuvial and lacustrine deltaic sedimentation. Eight outcrop sections across the Jurassic strata were meas-ured at a resolution of meters in southern Junggar Basin. Controlling factors of sedimentary evolution and palaeoclimate changes in Junggar Basin during the Jurassic were discussed based on lithology, fossils and tectonic setting. In the Early to Middle Jurassic, the warm and wide Tethys Sea generated a strong monsoonal circulation over the central Asian continent, and provided adequate moisture for Junggar Basin. Coal-bearing strata of the Badaowan, Sangonghe, and Xishanyao Formations were developed under warm and humid palaeocli-mate in Junggar Basin. In the late Middle Jurassic, Junggar Basin was in a semi-humid and semi-arid environment due to global warming event. Stratigraphy in the upper part of the Mid-dle Jurassic with less plant fossils became multicolor or reddish from dark color sediments. During the Late Jurassic, collision of Lhasa and Qiangtang Block obstructed monsoon from the Tethys Sea. A major change in climate from semi-humid and semi-arid to arid conditions took place, and reddish strata of the Upper Jurassic were developed across Junggar Basin.

  12. Jurassic sedimentary evolution of southern Junggar Basin:Implication for palaeoclimate changes in northern Xinjiang Uygur Autonomous Region,China

    Institute of Scientific and Technical Information of China (English)

    Shun-Li; Li; Xing-He; Yu; Cheng-Peng; Tan; Ronald; Steel

    2014-01-01

    Junggar Basin,located in northern Xinjiang,presents continuous and multikilometer-thick strata of the Jurassic deposits.The Jurassic was entirely terrestrial fluvial and lacustrine deltaic sedimentation.Eight outcrop sections across the Jurassic strata were measured at a resolution of meters in southern Junggar Basin.Controlling factors of sedimentary evolution and palaeoclimate changes in Junggar Basin during the Jurassic were discussed based on lithology,fossils and tectonic setting.In the Early to Middle Jurassic,the warm and wide Tethys Sea generated a strong monsoonal circulation over the central Asian continent,and provided adequate moisture for Junggar Basin.Coal-bearing strata of the Badaowan,Sangonghe,and Xishanyao Formations were developed under warm and humid palaeoclimate in Junggar Basin.In the late Middle Jurassic,Junggar Basin was in a semi-humid and semi-arid environment due to global warming event.Stratigraphy in the upper part of the Middle Jurassic with less plant fossils became multicolor or reddish from dark color sediments.During the Late Jurassic,collision of Lhasa and Qiangtang Block obstructed monsoon from the Tethys Sea.A major change in climate from semi-humid and semi-arid to arid conditions took place,and reddish strata of the Upper Jurassic were developed across Junggar Basin.

  13. Jurassic sedimentary evolution of southern Junggar Basin: Implication for palaeoclimate changes in northern Xinjiang Uygur Autonomous Region, China

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    Shun-Li Li

    2014-04-01

    Full Text Available Junggar Basin, located in northern Xinjiang, presents continuous and multikilometer-thick strata of the Jurassic deposits. The Jurassic was entirely terrestrial fluvial and lacustrine deltaic sedimentation. Eight outcrop sections across the Jurassic strata were measured at a resolution of meters in southern Junggar Basin. Controlling factors of sedimentary evolution and palaeoclimate changes in Junggar Basin during the Jurassic were discussed based on lithology, fossils and tectonic setting. In the Early to Middle Jurassic, the warm and wide Tethys Sea generated a strong monsoonal circulation over the central Asian continent, and provided adequate moisture for Junggar Basin. Coal-bearing strata of the Badaowan, Sangonghe, and Xishanyao Formations were developed under warm and humid palaeoclimate in Junggar Basin. In the late Middle Jurassic, Junggar Basin was in a semi-humid and semi-arid environment due to global warming event. Stratigraphy in the upper part of the Middle Jurassic with less plant fossils became multicolor or reddish from dark color sediments. During the Late Jurassic, collision of Lhasa and Qiangtang Block obstructed monsoon from the Tethys Sea. A major change in climate from semi-humid and semi-arid to arid conditions took place, and reddish strata of the Upper Jurassic were developed across Junggar Basin.

  14. MIDDLE JURASSIC-LOWER CRETACEOUS BIOSTRATIGRAPHY IN THE CENTRAL PONTIDES (TURKEY): REMARKS ON PALEOGEOGRAPHY AND TECTONIC EVOLUTION

    OpenAIRE

    BORA ROJAY; DEMIR ALTINER

    1998-01-01

    The deposition of Jurassic-Lower Cretaceous carbonates in the Pontides was controlled mainly by the evolution of an Atlantic-type continental margin in the Tethys. The study of several stratigraphic sections from allochthonous slices and blocks of the North Anatolian Ophiolitic Melange provided insight into the Middle Jurassic-Early Cretaceous paleogeographic evolution of the Central Pontide Belt. The Callovian-Aptian successions span the Globuligerina gr. oxfordiana, Clypeina jurassica (equi...

  15. Lower cretaceous silcrete-ferricrete, at the northern end of the African Tethys shoreline, Maktesh Gadol, Israel

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    Azmon, E.; Kedar, Y.

    1985-04-01

    The lithostratigraphic relationships between the rock members across the Upper Jurassic to Lower Cretaceous unconformity in the Maktesh Gadol erosional crater in the Negev of Israel, show co-existence of silcretes and ferricretes at the base of the Lower Cretaceous rocks, and a change from biomicrite to biomicrite silt and back to biomicrite, near the top of the exposed Upper Jurassic rocks. The base of the Cretaceous is interpreted as the remains of a "B" zone of illuviation of a partly developed soil formation, which derived its components from the underlying biomicritic rocks or biomicrites and from overlying eolian and fluviatile marls, and which formed by a very long duration of weathering beneath a desert floor environment. This lithostratigraphy, displaying alternating clastic to non-clastic carbonates, followed by formation of a soil profile, may be a consequence of a fluctuating Tethys sea on the African plate in the Late Jurassic and consequent major marine regression in the Early Cretaceous.

  16. The Alpine loop of the tethys zone

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    Bemmelen, R.W. van

    1969-01-01

    The Alpine loop in Europe results from semi-autochthonous crustal movements which are restricted to the mobile Tethys zone. Its evolution cannot be explained by a uniform northward drift and push of the African continent; it has to be sought, in the first place, in geodynamic processes occurring in

  17. The Alpine loop of the tethys zone

    NARCIS (Netherlands)

    Bemmelen, R.W. van

    1969-01-01

    The Alpine loop in Europe results from semi-autochthonous crustal movements which are restricted to the mobile Tethys zone. Its evolution cannot be explained by a uniform northward drift and push of the African continent; it has to be sought, in the first place, in geodynamic processes occurring in

  18. Late Permian to recent magmatic activity on the African-Arabian margin of Tethys

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    Wilson, M. [Leeds University (United Kingdom). School of Earth Sciences; Guiraud, R. [Universite de Montpellier II (France). Laboratoire de Geophysique et Tectonique; Moreau, C. [Universite de la Rochelle (France). Departement des Sciences de la Terre; Bellion, Y.J.-C. [Laboratoire de Geologie, Avignon (France). Faculte des Science

    1998-12-31

    Magmatic activity on the African-Arabian margin of Tethys has fluctuated significantly during the past 250 Ma in response to major phases of mantle plume activity and to extensional stresses within the African plate related to periods of continental break-up. A series of maps have been compiled, based upon stratigraphic constraints and K-Ar and {sup 40}Ar-{sup 39}Ar age determinations, to illustrate the changing patterns of igneous activity since the Late Permian. These are divided into five stages: I, Late Permian (256 Ma)-Latest Triassic (208 MA); II, Early Jurassic (208 Ma, Liassic)-Mid Jurassic (157 Ma, Dogger); III, Late Jurassic (157 Ma)-Earliest Aptian (120 Ma); IV, Mid Aptian (119 Ma)-Mid Eocene (42 Ma); V, Late Eocene (42 Ma)-Recent. Magmatism appears to be extremely long-lived in a number of areas (e.g. Sudan, Air), with volcanic centres located along major basement fault zones, such as the Guinean-Nubian lineaments. (author)

  19. Modeling the Middle Jurassic ocean circulation

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    Maura Brunetti

    2015-10-01

    Full Text Available We present coupled ocean–sea-ice simulations of the Middle Jurassic (∼165 Ma when Laurasia and Gondwana began drifting apart and gave rise to the formation of the Atlantic Ocean. Since the opening of the Proto-Caribbean is not well constrained by geological records, configurations with and without an open connection between the Proto-Caribbean and Panthalassa are examined. We use a sea-floor bathymetry obtained by a recently developed three-dimensional (3D elevation model which compiles geological, palaeogeographical and geophysical data. Our original approach consists in coupling this elevation model, which is based on detailed reconstructions of oceanic realms, with a dynamical ocean circulation model. We find that the Middle Jurassic bathymetry of the Central Atlantic and Proto-Caribbean seaway only allows for a weak current of the order of 2 Sv in the upper 1000 m even if the system is open to the west. The effect of closing the western boundary of the Proto-Caribbean is to increase the transport related to barotropic gyres in the southern hemisphere and to change water properties, such as salinity, in the Neo-Tethys. Weak upwelling rates are found in the nascent Atlantic Ocean in the presence of this superficial current and we discuss their compatibility with deep-sea sedimentological records in this region.

  20. HEAVY METALS CONTAMINATION IN FISH OF THE LIGURIAN SEA

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    M. Prearo

    2013-02-01

    Full Text Available Aim of this investigation was to evaluate heavy metals contamination (mercury, cadmium and lead in fish and shellfish from Ligurian Sea. 58 muscle samples (45 fish and 13 shellfish were collected and analyzed. 20 samples exceeded the maximum residue limits (MRLs set by regulation for mercury (16 fish and 4 shellfish samples, while only one fish sample was not consistent with the MRL for lead. Therefore, 35,8% of Ligurian fishing turned out to be not adequate and potentially harmful for consumers. In order to estimate the real risk for human health it is necessary to enforce this study, correlating the results with fish species and with the effective fish consumption.

  1. Upper layer current variability in the Central Ligurian Sea

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    P. Picco

    2010-03-01

    Full Text Available Long-time series of surface currents and meteorological parameters were analysed to estimate the variability of the upper layer circulation as a preliminary study of the Ligurian Air-Sea Interaction Experiment (LASIE07. Current meter data were collected by an upward-looking RDI Sentinel 300 kHz ADCP deployed in the Central Ligurian Sea (43°47.77' N; 9°02.85' E near the meteo-oceanographic buoy ODAS ITALIA1 for over eight months. The ADCP sampled the upper 50 m of water column at 8 m vertical resolution and 1 h time interval; surface marine and atmospheric hourly data were provided by the buoy. Currents were mainly barotropic and directed NW, according to the general circulation of the area, had a mean velocity of about 18 cm s−1 and hourly mean peaks up to 80 m s−1. Most of the observed variability in the upper thermocline was determined by inertial currents and mesoscale activity due to the presence of the Ligurian Front. Local wind had a minor role in the near-surface circulation but induced internal waves propagating downward in the water column.

  2. Jurassic Amber in Lebanon

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    Dany AZAR; Raymond G(E)ZE; Antoine EL-SAMRANI; Jacqueline MAALOULY; André NEL

    2010-01-01

    Reports of amber predating the Lower Cretaceous are unusual and scarce; they mostly refer to amber pieces of millimetric dimension.In the present study,we report the discovery of 10 new outcrops of Jurassic amber in Lebanon.Some of these had large centimetric-sized pieces of amber.The new localities are described,amber is characterized,and its infrared spectra given.Although the new Jurassic amber yielded to date no more than fungal inclusions,this material is significant and promising.The discovery of several Jurassic outcrops provides crucial information on the prevailing paleoenvironment of that time.

  3. A revised subduction inception model to explain the Late Cretaceous, doubly vergent orogen in the pre-collisional western Tethys: evidences from the Northern Apennine

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    Meneghini, Francesca; Marroni, Michele; Pandolfi, Luca

    2017-04-01

    Orogenic processes are widely demonstrated to be strongly controlled by inherited structures. The paleogeography of the converging margins, and the tectonic processes responsible for their configuration, will influence the location of subduction initiation, the distribution of deformation between upper and lower plate, the shape of the accretionary prism and of the subsequent orogeny, through controlling the development of single or doubly-vergent orogens, and, as a corollary, the modality of exhumation of metamorphosed units. The "alpine age" collisional belts of the Mediterranean area are characterized by tangled architectures derived from the overlapping of several deformation events related to a multiphase, long history that comprises not only the collision of continental margins, but that can be regarded as an heritage of both the rifting-related configuration of the continental margins, and the subduction-related structures. The Northern Apennines is a segment of these collisional belts that originated by the Late Cretaceous-Middle Eocene closure of the northern branch of the western Tethys, and the subsequent Late Eocene-Early Oligocene continental collision between the Europe and Adria plates. Due to a different configuration of the paired Adria and Europe continental margins, inherited from a rifting phase dominated by asymmetric, simple-shear kinematics, the Northern Apennines expose a complex groups of units, referred to as Ligurian Units, that record the incorporation into the subduction factory of either fragments of the Ligure-Piemontese oceanic domain (i.e. Internal Ligurian Units), and various portions of the thinned Adria margin (i.e. External Ligurian Units), describable as an Ocean-Continent Transition Zone (OCTZ). The structural relationships between these groups of Units are crucial for the definition of the pre-collisional evolution of the belt and have been the subject of big debates in the literature, together with the location and

  4. Origin of gabbroic sequences from the Ligurian ophiolites: implications for lower crust generation at slow spreading settings

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    Tribuzio, R.; Renna, M.; Sanfilippo, A.

    2011-12-01

    The Ligurian Jurassic ophiolites (northern Apennines, Italy) are lithospheric remnants of an embryonic slow spreading basin that developed in conjunction with the opening of the Central Atlantic Ocean. These ophiolites are characterized by km-scale gabbroic sequences intruded into mantle peridotites and exposed at the seafloor. These gabbroic sequences mostly consist of troctolites, olivine-gabbros and clinopyroxene-rich gabbros and locally include olivine-rich troctolite bodies (Renna and Tribuzio, 2011). The large-scale gabbroic sequences from the Ligurian ophiolites also enclose a few mantle peridotite bodies and bear striking structural and compositional resemblances to the gabbroic sequences from modern slow spreading ridges (Sanfilippo and Tribuzio, 2011). Field observations and petrological and geochemical data are used to constrain a conceptual model for the formation of the gabbroic sequences from the Alpine ophiolites. The proposed model begins with a hot mantle evolution under plagioclase facies conditions, in which melt transport occurred mainly in the form of grain scale porous flow. In particular, reactive channeling of olivine-saturated melts formed replacive dunitic conduits, whereas residual orthopyroxene-saturated melts led to melt impregnation of the mantle section. The hot lithospheric evolution is followed by an evolution characterized by melt transport through fractures, which started with crystallization of melt into gabbroic dikes. This diking event is likely correlated with the formation of the olivine-rich troctolites. These rocks show a process of infiltration of MORB-type melts saturated in plagioclase + clinopyroxene into an olivine-spinel matrix that is inferred to have formed in mantle melt conduits of replacive origin. As the mantle section cooled significantly, the dip of the melt migration structures evolved from sub-vertical to sub-horizontal. This is shown by the occurrence of sill-shaped gabbroic intrusions, which locally

  5. Jurassic fishes of Gondwana

    Directory of Open Access Journals (Sweden)

    Adriana López-Arbarello

    2008-12-01

    Full Text Available The Jurassic is an important period for understanding the origin of modern fish faunas, since it saw the first radiation - and in some cases the origin - of most modern groups. In chondrichthyans, neoselachian sharks and rays diversified during this time. In actinopterygians, the neopterygians, and among them the teleosts, experienced an important radiation, which led to the appearance of several of the modern teleosts groups. In the sarcopterygians, dipnoans and actinistians approached their current forms. However, the Jurassic fossil record of fishes is strongly biased towards the Northern Hemisphere. The only notable Early Jurassic fish fauna from Gondwana is that of the Kota Formation of India. For the Middle Jurassic, the most important Gondwanan fish faunas are those of the Aalenian-Bathonian Stanleyville Beds of the Democratic Republic of Congo, in which a distinct freshwater and a marine fauna are found. In the Late Jurassic, the Gondwanan record is slightly better, with important marine faunas being known from the Oxfordian Quebrada del Profeta in Chile and the Tithonian Vaca Muerta Formation of Argentina. Freshwater faunas have been described from the Tithonian Talbragar Beds of eastern Australia and the Tithonian Cañadón Calcáreo Formation of Argentina. The taxonomic composition of the known marine actinopterygian faunas of Gondwana is in general agreement with faunas of the Northern Hemisphere. However, the Jurassic fish record from Gondwana is highly incomplete both stratigraphically and geographically, and most faunas are in need of revision, further hampering an interpretation of Jurassic fish evolution in the Southern Hemisphere.

  6. 2D Numerical simulations of intraoceanic subduction: the case study of the Ligurian Alps.

    Science.gov (United States)

    Malatesta, Cristina; Gerya, Taras; Federico, Laura; Scambelluri, Marco; Crispini, Laura; Capponi, Giovanni

    2010-05-01

    Intraoceanic subduction is an important part of the present and past subduction systems, and some features of such process are not yet fully understood. We therefore studied intraoceanic subduction zones with the help of 2D numerical models, analyzing the parameters influencing their evolution in time and space. We applied the finite differences method on a rectangular grid, to calculate properties such as pressure, temperatures and velocities inside the models solving a set of equations. The latter comprise the Stokes equation of motion, the continuity equation and the heat transport equation. Temperature and velocities are computed on the nodes of the grid whereas pressures are calculated for the geometrical centers of the cells. We defined material properties such as density or viscosity on marker points, initially positioned on a regular rectangular grid. The markers and therefore the material properties are moved through the mesh according to the velocity field using the forth order Runge-Kutta method (Gerya et al. 2002). Subduction is forced to begin at a weak zone in the lithospheric mantle within an oceanic basin of prescribed width. The effect of different arrangements of rock bodies inside the subducting lithosphere on the evolution of the process was carefully analyzed. In particular we reproduced two distinct structures of the oceanic lithosphere: i) the layered oceanic crust made up of a stratified succession typical of fast-spreading ridges and ii) the oceanic lithosphere typical of slow and ultra-slow spreading centers, where an incomplete sequence is observable. The latter structure lacks a sheeted dike complex, has a low volume of gabbros and basalts and gabbros form discrete intrusions in variably serpentinized peridotites (Lagabrielle et al., 1997; Mével, 2003). Such an "heterogeneous" structure is characteristic of the Alpine and Appennine ophiolites that characterized the Mesozoic Ligurian Tethys located between Europe and Adria. The depth of

  7. Tethys- and Atlas-related deformations in the Triassic Basin, Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, J.S.; Moore, S.R.; Quarles, A.I. [ARCO International Oil and Gas Company, Plano, TX (United States)

    1995-08-01

    Petroleum provinces of Algeria can be divided into Paleozoic and Mesozoic domains. Paleozoic basins are located on the Gondwanaland paleo-continent where the last significant tectonic episode is ascribed to the Late Paleozoic Hercynian Orogeny. Mesozoic basins are located on the south margin of the Neo-Tethyan seaway. These basins were subject to varying degrees of contractional deformation during the Cenozoic Atlas Orogeny. The Triassic Basin of Algeria is a Tethyan feature located above portions of the Paleozoic Oued M`ya and Ghadames Basins. Paleozoic strata are deeply truncated at the Hercynian Unconformity on a broad arch between the older basins. This is interpreted to reflect rift margin rebound during Carboniferous time. Continental Lower Triassic sediments were deposited in a series of northeast trending basins which opened as the Neo-Tethys basin propagated from east to west between Africa and Europe. Middle Triassic marine transgression from the east resulted in evaporate deposition persisting through the Early Jurassic. Passive margin subsidence associated with carbonate marine deposition continued through the Early Cretaceous. Several zones of coeval wrench deformation cross the Atlas and adjoining regions. In the Triassic Basin, inversion occurred before the end of the Early Cretaceous. This episode created discrete uplifts, where major hydrocarbon accumulations have been discovered, along northeast trending lineaments. During the Eocene, the main phase of the Atlas Orogeny produced low amplitude folding of Jurassic and Cretaceous sediments. The folds detach within the Triassic-Jurassic evaporate interval. Many of these folds have been tested without success, as the deeper reservoirs do not show structural closure.

  8. Study of tsunami propagation in the Ligurian Sea

    Directory of Open Access Journals (Sweden)

    E. Pelinovsky

    2001-01-01

    Full Text Available Tsunami propagation is analyzed for the Ligurian Sea with particular attention on the French coasts of the Mediterranean. Historical data of tsunami manifestation on the French coast are analyzed for the period 2000 B.C.–1991 A.D. Numerical simulations of potential and historical tsunamis in the Ligurian Sea are done in the context of the nonlinear shallow water theory. Tsunami wave heights as well as their distribution function is calculated for historical tsunamis and it is shown that the log-normal distribution describes reasonably the simulated data. This demonstrates the particular role of bottom irregularities for the wave height distribution function near the coastlines. Also, spectral analysis of numerical tide-gauge records is done for potential tsunamis, revealing the complex resonant interactions between the tsunami waves and the bottom oscillations. It is shown that for an earthquake magnitude of 6.8 (averaged value for the Mediterranean Sea the tsunami phenomenon has a very local character but with long duration. For sources located near the steep continental slope in the vicinity of the French-Italian Rivera, the tsunami tide-gauge records in the vicinity of Cannes – Imperia present irregular oscillations with a characteristic period of 20–30 min and a total duration of 10–20 h. For the western French coasts the amplitudes are significantly less with characteristic low-frequency oscillations (period of 40 min–1 h.

  9. Exploring Jurassic Park.

    Science.gov (United States)

    Simmons, Patricia E.; Wiley, Clyde

    1993-01-01

    Describes several student-tested activities built around "Jurassic Park." The activities feature students engaged in role-playing scenarios, investigative research projects, journal writing and communications skills activities, cooperative learning groups, and learning experiences that make use of reading skills and mathematical knowledge. (PR)

  10. Exploring Jurassic Park.

    Science.gov (United States)

    Simmons, Patricia E.; Wiley, Clyde

    1993-01-01

    Describes several student-tested activities built around "Jurassic Park." The activities feature students engaged in role-playing scenarios, investigative research projects, journal writing and communications skills activities, cooperative learning groups, and learning experiences that make use of reading skills and mathematical knowledge. (PR)

  11. On some electrical effects of the 1887 Ligurian earthquake

    Science.gov (United States)

    Poirier, Jean-Paul; Perrier, Frédéric; Le Mouël, Jean-Louis

    2008-04-01

    Significant electrical effects were observed in association with the 23 February 1887 Ligurian earthquake. Magnetic oscillatory signals, recorded in several locations in France and England, are inconclusive, as they can be interpreted as a consequence of the shaking of the magnetometers induced by the seismic waves. While observations in a telephone switch in Cannes could suggest the presence of electrical currents during the earthquake, evidence that is more convincing was reported near Monaco, where a telegraph operator received an electric shock that caused muscular tetanisation. This could be the first reliable evidence of a strong coseismic electrical potential. The minimal ground electric potential difference able to generate this condition is estimated to be of the order of 40 V. These observations, combined with similar accounts in Italy and in Martinique during early operation of telegraph networks, also suggest the existence of electrical phenomena occurring seconds or minutes before the main shock.

  12. Latest Jurassic-early Cretaceous regressive facies, northeast Africa craton

    Energy Technology Data Exchange (ETDEWEB)

    van Houten, F.B.

    1980-06-01

    Nonmarine to paralic detrital deposits accumulated in six large basins between Algeria and the Arabo-Nubian shield during major regression in latest Jurassic and Early Cretaceous time. The Ghadames Sirte (north-central Libya), and Northern (Egypt) basins lay along the cratonic margin of northeastern Africa. The Murzuk, Kufra, and Southern (Egypt) basins lay in the south within the craton. Data for reconstructing distribution, facies, and thickness of relevant sequences are adequate for the three northern basins only. High detrital influx near the end of Jurassic time and in mid-Cretaceous time produced regressive nubian facies composed largely of low-sinuosity stream and fahdelta deposits. In the west and southwest the Ghadames, Murzuk, and Kufra basins were filled with a few hundred meters of detritus after long-continued earlier Mesozoic aggradation. In northern Egypt the regressive sequence succeeded earlier Mesozoic marine sedimentation; in the Sirte and Southern basins correlative deposits accumulated on Precambrian and Variscan terranes after earlier Mesozoic uplift and erosion. Waning of detrital influx into southern Tunisia and adjacent Libya in the west and into Israel in the east initiated an Albian to early Cenomanian transgression of Tethys. By late Cenomanian time it had flooded the entire cratonic margin, and spread southward into the Murzuk and Southern basins, as well as onto the Arabo-Nubian shield. Latest Jurassic-earliest Cretaceous, mid-Cretaceous, and Late Cretaceous transgressions across northeastern Africa recorded in these sequences may reflect worldwide eustatic sea-level rises. In contrast, renewed large supply of detritus during each regression and a comparable subsidence history of intracratonic and marginal basins imply regional tectonic control. 6 figures.

  13. JURASSIC PALAEOGEOGRAPHY OF THE TRANSDANUBIAN CENTRAL RANGE (HUNGARY

    Directory of Open Access Journals (Sweden)

    ATTILA VÖRÖS

    1998-03-01

    Full Text Available The Transdanubian Central Range (TCR is a flattened range of hills in northern Transdanubia (Hungary, formed mainly by Mesozoic carbonate rocks showing strong facies similarities with the Southern Alps and the Austroalpine domain. The Jurassic system is divided into several formations of predominantly pelagic limestones. Ammonoids are frequent and were collected bed-by-bed in numerous sections, providing an excellent biostratigraphic resolution. The thickness of the Jurassic system is usually small but changes along the strike of the TCR. It reaches a maximum thickness of 500 m in the western part; is very variable (10-400 m in the central segment (Bakony Mts. and rather low (less than 100 m in the east (Gerecse. In the Bakony segment, the thickness variation reflects the strongly dissected topography of the Jurassic sea-floor. Synsedimentary tectonics is dominated by normal faults; tilted blocks and listric faults may be inferred only in the east.Five main steps were identified in the palaeogeographic evolution: 1 Late Hettangian: carbonate oolitic shoals prevail, except for a few sites where non-deposition or neritic sediments occur. 2 Sinemurian and Pliensbachian: tectonic disintegration resulted in an intricate pattern of submarine horsts and intervening basins, with condensed sedimentation or non-deposition on the horsts and thicker, continuous sedimentary sequences in the basins. The submarine topographic highs are surrounded by aprons of redeposited material (scarp breccias, brachiopod coquinas, crinoidal calcarenites, spiculitic cherty limestones, while pure or argillaceous limestones (Rosso Ammonitico prevail in the distal areas. 3 Early Toarcian: the Tethys-wide anoxic event is superimposed on the previous submarine bottom topography; the resulting black shales and sedimentary Mn-ores are concentrated on the western sides of some horsts. 4 Dogger to Early Malm: radiolarites with heterochronous lower and upper boundaries (Aalenian to

  14. Tethys and Annex IV Progress Report for FY 2012

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, Luke A.; Butner, R. Scott; Whiting, Jonathan M.; Copping, Andrea E.

    2013-09-01

    The marine and hydrokinetic (MHK) environmental Impacts Knowledge Management System, dubbed “Tethys” after the mythical Greek titaness of the seas, is being developed by the Pacific Northwest National Laboratory (PNNL) to support the U.S. Department of Energy’s Wind and Water Power Program (WWPP). Functioning as a smart database, Tethys enables its users to identify key words or terms to help gather, organize and make available information and data pertaining to the environmental effects of MHK and offshore wind (OSW) energy development. By providing and categorizing relevant publications within a simple and searchable database, Tethys acts as a dissemination channel for information and data which can be utilized by regulators, project developers and researchers to minimize the environmental risks associated with offshore renewable energy developments and attempt to streamline the permitting process. Tethys also houses a separate content-related Annex IV data base with identical functionality to the Tethys knowledge base. Annex IV is a collaborative project among member nations of the International Energy Agency (IEA) Ocean Energy Systems – Implementing Agreement (OES-IA) that examines the environmental effects of ocean energy devices and projects. The U.S. Department of Energy leads the Annex IV working with federal partners such as the Federal Energy Regulatory Commission (FERC), the Bureau of Ocean Energy Management (BOEM), and the National Oceanic Atmospheric Administration (NOAA). While the Annex IV database contains technical reports and journal articles, it is primarily focused on the collection of project site and research study metadata forms (completed by MHK researchers and developers around the world, and collected by PNNL) which provide information on environmental studies and the current progress of the various international MHK developments in the Annex IV member nations. The purpose of this report is to provide a summary of the content

  15. Jurassic Park: Adventure in Learning.

    Science.gov (United States)

    Shams, Marcia; Boteler, Trina

    1993-01-01

    Describes using the movie "Jurassic Park" as a foundation for a middle school interdisciplinary unit involving science, math, language arts, history, and geography. Suggested books and activities are presented. (PR)

  16. Jurassic Park: Adventure in Learning.

    Science.gov (United States)

    Shams, Marcia; Boteler, Trina

    1993-01-01

    Describes using the movie "Jurassic Park" as a foundation for a middle school interdisciplinary unit involving science, math, language arts, history, and geography. Suggested books and activities are presented. (PR)

  17. On microseisms recorded near the Ligurian coast (Italy) and their relationship with sea wave height

    DEFF Research Database (Denmark)

    Ferretti, G.; Zunino, Andrea; Scafidi, D.;

    2013-01-01

    In this study, microseism recordings from a near coast seismic station and concurrent significant sea wave heights (H13 ) are analysed to calibrate an empirical relation for predicting sea wave height in the Ligurian Sea. The study stems from the investigation of the damaging sea storms occurred ...

  18. MIDDLE JURASSIC-LOWER CRETACEOUS BIOSTRATIGRAPHY IN THE CENTRAL PONTIDES (TURKEY: REMARKS ON PALEOGEOGRAPHY AND TECTONIC EVOLUTION

    Directory of Open Access Journals (Sweden)

    BORA ROJAY

    1998-07-01

    Full Text Available The deposition of Jurassic-Lower Cretaceous carbonates in the Pontides was controlled mainly by the evolution of an Atlantic-type continental margin in the Tethys. The study of several stratigraphic sections from allochthonous slices and blocks of the North Anatolian Ophiolitic Melange provided insight into the Middle Jurassic-Early Cretaceous paleogeographic evolution of the Central Pontide Belt. The Callovian-Aptian successions span the Globuligerina gr. oxfordiana, Clypeina jurassica (equivalent of the Tubiphytes morronensis zone, Protopeneroplis ultragranulata (with the Haplophragmoides joukowskyi subzone, Montsalevia salevensis, Hedbergella delrioensis - Hedbergella planispira - Leupoldina - Globigerinelloides and Globigerinelloides algerianus biozones. Two major stratigraphic gaps corresponding to the pre-Callovian and Hauterivian-Early Aptian ages are recognised within the successions. Lithostratigraphic and biostratigraphic studies indicate strong similarities in the evolution of the successions in the Amasya region (Central Pontides and Biga-Bursa-Bilecik (BBB Platform (North-western Anatolia. 

  19. Origination and death of petroleum systems along the Late Jurassic/Early Cretaceous northern Tethyan margin

    Energy Technology Data Exchange (ETDEWEB)

    Golonka, J. [Mobil Research and Development Corp., Dallas, TX (United States); Kiessling, W. [Erlangen-Nuernberg Univ., Erlangen (Germany). Inst. fuer Geologie und Mineralogie; Krobicki, M. [Academy of Mining and Metallurgy, Cracow (Poland). Inst. of Petroleum Engineering; Bocharova, N.Y. [Russian Academy of Sciences, Moscow (Russian Federation). Center for Program Studies

    1997-09-01

    Breakup of Pangea during Jurassic and Cretaceous times created a system of rifts along the northern Tethyan margin. Some of these rifts developed into oceanic basins while others developed on continental crust and turned into aulacogenes. The basins were separated from the main Tethys ocean by several plates and ridges. Partial uplift of the main European plate and late Kimmerian orogeny resulted in the establishment of restricted conditions in the marginal Tethyan basins. The paleogeographic and paleoclimatic setting favoured upwelling along the ridges and continental margins. Source rock prediction value modelling placed Tethyan marginal basins among the best Jurassic source rocks of the world. Self-contained petroleum systems consisting of source rocks, carbonate reservoirs and evaporitic seals occur in the area east of Poland. Actual hydrocarbon production is ongoing in Afghanistan and the Amu-Daria province. Some of Carpathian oils might also be sourced by Late Jurassic/Early Cretaceous rocks. In the western area, petroleum systems were destroyed during the Alpine orogeny.

  20. The Jurassic of Denmark and Greenland: The Middle Jurassic of western and northern Europe: its subdivisions, geochronology and correlations

    Directory of Open Access Journals (Sweden)

    Callomon, John H.

    2003-10-01

    Full Text Available The palaeogeographic settings of Denmark and East Greenland during the Middle Jurassic are outlined. They lay in the widespread epicontinental seas that covered much of Europe in the post-Triassic transgression. It was a period of continuing eustatic sea-level rise, with only distant connections to world oceans: to the Pacific, via the narrow Viking Straits between Greenland and Norway and hence the arctic Boreal Sea to the north; and to the subtropical Tethys, via some 1200 km of shelf-seas to the south. The sedimentary history of the region was strongly influenced by two factors: tectonism and climate. Two modes of tectonic movement governed basinal evolution: crustal extension leading to subsidence through rifting, such as in the Viking and Central Grabens of the North Sea; and subcrustal thermal upwelling, leading to domal uplift and the partition of marine basins through emergent physical barriers, as exemplified by the Central North Sea Dome with its associated volcanics. The climatic gradient across the 30º of temperate latitude spanned by the European seas governed biotic diversity and biogeography, finding expression in rock-forming biogenic carbonates that dominate sediments in the south and give way to largely siliciclastic sediments in the north. Geochronology of unrivalled finesse is provided by standard chronostratigraphy based on the biostratigraphy of ammonites. The Middle Jurassic saw the onset of considerable bioprovincial endemisms in these guide-fossils, making it necessary to construct parallel standard zonations for Boreal, Subboreal or NW European and Submediterranean Provinces, of which the NW European zonation provides the primary international standard. The current versions of these zonations are presented and reviewed.

  1. Apparent polar wander path for Adria extended by new Jurassic paleomagnetic results from its stable core: Tectonic implications

    Science.gov (United States)

    Márton, Emő; Zampieri, Dario; Ćosović, Vlasta; Moro, Alan; Drobne, Katica

    2017-03-01

    As a continuation of a systematic paleomagnetic research in the northern part of stable Adria, which provided a well-defined apparent polar wander (APW) path for the Cretaceous-Eocene, we present new paleomagnetic results for the Jurassic. These new data were obtained from 15 geographically distributed localities from the Trento platform (eastern Southern Alps) using standard paleomagnetic approach. The Lower Jurassic shallow water carbonates are not considered for tectonic interpretation, due to inconsistent inclinations. The Middle and Upper Jurassic Rosso Ammonitico provided excellent kinematic constraints. With the new Jurassic results, an APW is now defined for Adria for the 167-40 Ma interval. It is well constrained for timing of important changes, like the speed and the sense of rotations. This APW suggests that the CW rotation and southward shift changed to the opposite at 155.1 ± 5.3 Ma, signifying a dramatic change in the life of the Neo-Tethys, from opening to closing. The latter is manifested in fast CCW rotation and northward movement of Adria up to 102.9 ± 2.4 Ma and moderate displacements in the same manner in post-103 Ma times. Combined data sets from stable Istria and the foreland of the Southern Alps point to an approximately 15° CW rotation with respect to Africa at the end of the Cretaceous, and an about 25° in the CCW sense, after the Eocene.

  2. A unique fossil record from neptunian sills: the world's most extreme example of stratigraphic condensation (Jurassic, western Sicily)

    Science.gov (United States)

    Wendt, Jobst

    2017-06-01

    Neptunian sills at Rocca Busambra, a fragment of the Trapanese/Saccense Domain in western Sicily, host the most abundant ammonite and gastropod fauna which has ever been recorded from the Jurassic of the western Tethys. The fauna is dominated by parautochthonous organisms which were swept into the sills by gentle transport. Ammonites are characterized by perfect preservation and small size, a feature which is due to the predominance of microconchs but also of stunting. The most complete sill is 0.7 m thick and could be separated into 17 levels which range in age from the early Toarcian into the late Kimmeridgian, thus representing the most extreme case of palaeontologically and depositionally documented stratigraphic condensation in Earth history. The unique feature of the Rocca Busambra sills is due to the interaction of three processes: extreme stratigraphic condensation on the sea floor, weak tectonic fracturing of the host rock and repeated reopening on top of already existing sills. Contrasting percentages of gastropods in individual levels reflect sea-level oscillations which correspond to long known low- and highstands during the Jurassic of the western Tethys. Comparisons with other ammonite-bearing sill faunas reveal several similarities, but represent only short-timed phases of tectonic pulses and deposition.

  3. Besieged by Trojans: Material Exchange between Tethys and its Coorbital Moons

    Science.gov (United States)

    Nayak, Michael; Rhoden, Alyssa R.; Asphaug, Erik

    2016-10-01

    Two small Trojan moons are coorbital with the Saturnian moon Tethys: Calypso (20-km diameter) resides in the trailing L5 Lagrangian point of Tethys' orbit around Saturn, while Telesto (25-km diameter) occupies the leading L4 Lagrangian point. Due to their fixed location with respect to Tethys, consistent material transfer to Tethys occurs whenever there is a primary impact on either of the Trojan moons. Here we investigate this material exchange, and its implications for the cratering history of Tethys. Multiple craters in excess of 1-km in diameter are seen on both Trojan moons [1]. We model the evolution of ejecta escaping from the largest five and seven craters on Calypso and Telesto respectively. The Maxwell Z-model [2] is used, with an implicit gravity-regime cratering assumption, to approximate outbound ejecta velocity distributions. The smallest craters considered on Calypso and Telesto are 1.35 and 1.9 km in diameter respectively; these impacts would have generated a significant amount of sesquinary ejecta [3] in orbits coorbital to that of Tethys. We model the evolution of these sesquinary ejecta in the Saturnian gravity system across 100 years and track their impact locations [e.g. 4]. Our results show that a large fraction of sesquinary ejecta created by primary impacts to either Trojan is likely to impact Tethys; the coorbital nature of the source bodies results in a significant fraction of this ejecta being incident at low impact velocities and low (oblique) impact angles. We present results of ongoing work to convolve these results with observed crater populations and morphologies on Tethys. The persistence of sesquinary impactors inbound to Tethys suggests that such impacts are a relatively frequent process. Additional sources of impactor material, such as from material excavated by primary impacts to Tethys and later reaccreted, will also be discussed. [1] Thomas et al., 2013, Icarus [2] Melosh, 1989, Oxford Univ. Press [3] Zahnle et al., 2008

  4. Polychlorinated biphenyls and pesticides in surficial coastal sediments of the Ligurian Sea

    Energy Technology Data Exchange (ETDEWEB)

    Bertolotto, R.M.; Cuneo, C.; Albanese, S. [ARPAL, Direzione Scientifica, Genova (Italy); Magherini, A. [ARPAL, Dipartimento di Genova, Genova (Italy); Frignani, M.; Bellucci, L.G.; Alvarado-Aguilar, D. [ISMAR, Sezione di Geologia Marina, Bologna (Italy)

    2004-09-15

    Polychlorinated biphenyls (PCBs) and chlorinated pesticides, such as DDT and its analogues, are organic contaminants widespread throughout the terrestrial and oceanic environments due to their common use and their resistance to degradation. Since harmful effects have been associated to these chemicals and well documented, they are classified as priority pollutants by both the US Environmental Protection Agency (EPA) and the European Union. Because of the very low solubility in water and the tendency to adsorb onto sediment particles, the ultimate fate of both PCBs and DDTs in the marine environment is the incorporation into sediments. Hence, the concentrations of these chlorinate chemicals in bottom sediments can provide an insight on the quality of the environment and the potential threat to marine organisms and human beings. The Ligurian Sea belongs to the north part of the western Mediterranean. The coastal morphology of the Liguria Region is rather variable, and frequently cliffs drop sheer to the sea. The limited width of the coastal zone, comprised between the sea and the mountains, determined a gathering of the urban areas with a consequent concentration of both civil and industrial presence in a narrow but highly populated territory. In particular Genova, but also other cities have a long history of industrial and harbour activities, whereas long tracts of the coast are dedicated to tourism. The circulation of the Ligurian Sea is rather well known. In particular, surface and intermediate currents follow a cyclonic circulation. However local circulation is the true responsible of the dispersion of sediment material along the coast, and these alongshore currents often cause an eastward oriented transport. The Ligurian coastal zone is very developed, and hosts all sort of industrial, agricultural and tourist activities that can be sources of persistent organochlorine chemicals. Therefore, the purpose of this study was to assess concentrations, distributions

  5. Preface——Jurassic of China and Environs: Stratigraphy, Basin History, and Paleoenvironment

    Institute of Scientific and Technical Information of China (English)

    SHA JinGeng

    2009-01-01

    @@ The Jurassic is a geologically very complicated period in Earth history, spanning from 200 to 145 Ma. The Pangean supercontinent and even the Gondwana-land broke up, and the violent circum Paleo-Pacific (Yanshan) orogeny and the collisions between Paleo-Pacific margins took place, both accompanied by extensive volcanism that may have been the cause of major environmental and biotic changes. With the rifting of the Pangea, North America drifted northwestward, narrowing the Pacific, and the North Atlantic opened, resulting in the formation of the Hispanic epicontinental seaway along the rifting area between North America, South America, and Africa and providing a corridor (Hispanic Corridor) for migration and exchange of biota between the Tethys and Paleo-Pacific.

  6. Late Jurassic-Early Cretaceous episodic development of the Bangong Meso-Tethyan subduction: Evidence from elemental and Sr-Nd isotopic geochemistry of arc magmatic rocks, Gaize region, central Tibet, China

    Science.gov (United States)

    Zhang, Yu-Xiu; Li, Zhi-Wu; Yang, Wen-Guang; Zhu, Li-Dong; Jin, Xin; Zhou, Xiao-Yao; Tao, Gang; Zhang, Kai-Jun

    2017-03-01

    The Bangong Meso-Tethys plays a critical role in the development of the Tethyan realm and the initial elevation of the Tibetan Plateau. However, its precise subduction polarity, and history still remain unclear. In this study, we synthesize a report for the Late Jurassic-Early Cretaceous two-phase magmatic rocks in the Gaize region at the southern margin of the Qiangtang block located in central Tibet. These rocks formed during the Late Jurassic-earliest Cretaceous (161-142 Ma) and Early Cretaceous (128-106 Ma), peaking at 146 Ma and 118 Ma, respectively. The presence of inherited zircons indicates that an Archean component exists in sediments in the shallow Qiangtang crust, and has a complex tectonomagmatic history. Geochemical and Sr-Nd isotopic data show that the two-phase magmatic rocks exhibit characteristics of arc magmatism, which are rich in large-ion incompatible elements (LIIEs), but are strongly depleted in high field strength elements (HFSEs). The Late Jurassic-earliest Cretaceous magmatic rocks mixed and mingled among mantle-derived mafic magmas, subduction-related sediments, or crustally-derived felsic melts and fluids, formed by a northward and steep subduction of the Bangong Meso-Tethys ocean crust. The magmatic gap at 142-128 Ma marks a flat subduction of the Meso-Tethys. The Early Cretaceous magmatism experienced a magma MASH (melting, assimilation, storage, and homogenization) process among mantle-derived mafic magmas, or crustally-derived felsic melts and fluids, as a result of the Meso-Tethys oceanic slab roll-back, which triggered simultaneous back-arc rifting along the southern Qiangtang block margin.

  7. Permo-Triassic Events in the Eastern Tethys

    Science.gov (United States)

    Sweet, Walter C.; Zunyi, Yang; Dickins, J. M.; Hongfu, Yin

    2003-12-01

    Permian and Triassic rocks in the eastern Tethyan region form continuous marine sequences that record the waning phases of the Paleozoic and the early stages of the Mesozoic eras. This book describes and interprets these rocks, summarizing the distribution of major fossil groups in a way that will allow detailed comparison with strata of comparable age in the western Tethys and other parts of the world. The sixteen contributions by forty authors are the culmination of the five-year long International Geological Correlation Programme Project 203. The detailed information presented here is gathered from many areas in the eastern Tethyan region - from France to Australia - and will be of use in the evaluation of the major changes in the global marine biosphere known to have taken place at the end of the Paleozoic era. The stratigraphic record for this fascinating segment of Earth history is not widespread elsewhere in the world and is most continuous in the region covered by this book.

  8. A new ophthalmosaurid ichthyosaur from the Late Jurassic of Owadów-Brzezinki Quarry, Poland

    Directory of Open Access Journals (Sweden)

    Daniel Tyborowski

    2016-12-01

    Full Text Available A new Late Jurassic ophthalmosaurid ichthyosaur Cryopterygius kielanae sp. nov. is described from carbonate deposits of Owadów-Brzezinki Quarry, Central Poland, corresponding in age to the Agardhfjellet Formation (Tithonian, Middle Volgian of the Svalbard Archipelago. The new species is represented by three-dimensionally preserved bones which display several features characteristic for Cryopterygius; including appendicular skeleton, pectoral girdle and perhaps neural arches. The morphology of the Polish form is distinct enough from Cryopterygius kristiansenae from the Svalbard Archipelago to warrant erection of a new species. The size of the bones of Cryopterygius kielanae sp. nov. indicates that this species was smaller than the type species. Its diagnostic anatomical features include a humerus with prominent and well developed dorsal process located in the middle of the dorsal surface of the bone, prominent deltopectoral crest, relatively broad femur and absence of the wide groove on the quadrate articular condyle. The discovery of a new ophthalmosaurid ichthyosaur of the genus Cryopterygius in Poland suggests that the Owadów-Brzezinki area was a transition zone between the tropical Tethys Ocean and the Arctic basin during the Late Jurassic.

  9. Myth of a vast oceanic tethys, the India-Asia problem and earth expansion

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, A.R.

    1979-07-01

    Common belief in a vast oceanic Tethys is mistaken and results from attempts to reconstruct Pangaea on an Earth of constant dimensions. Tethys was an epicontinental sea, much longer than it was wide. India was simultaneously attached to Asia and formed part of Gondwanaland. This is possible only if, as Carey suggests, the Earth has expanded and the Indian Ocean formed as continents separated. Such separation was a single controlled event.

  10. LATE JURASSIC SCLERACTINIAN CORALS FROM G(E)RZ(E),NORTHWESTERN XIZANG (TIBET)%西藏改则的晚侏罗世石珊瑚

    Institute of Scientific and Technical Information of China (English)

    廖卫华; 纪占胜; 武桂春

    2012-01-01

    文中描述产自西藏北部改则县境内班公湖-怒江地层区内的石珊瑚17属23种(包括1个新种和6个未定种),根据珊瑚动物群的分析与对比可以确定它们的地质时代应为晚侏罗世(Late Jurassic),最可能是晚牛津期至启莫里期(Late Oxfordian-Kimmeridgian),那时正值全球性温暖气候环境下,在全世界不少地方,尤其是在特提斯(Tethys)海域形成了一定规模的珊瑚礁(coral-reef).%Although Mesozoic marine strata are well developed in Xizang (Tibet) and they include a very rich scleractinian coral fauna their study has been limited for a long time by the well known rigours of exploration on the Qinghai-Tibetan Plateau. The coral-bearing beds discussed here are located in the Late Oxfordian to Kimmeridgian Tukari Formation at northern Oma village of Gerze county, northwestern Xizang. They belong to the Bangong Co-Nujiang Stratigraphic Zone, which borders the Qiangtang Stratigraphic Zone in the North and the Gangdise Stratigraphic Zone in the South. The Jurassic scleractinian corals described and illustrated here from Oma comprise 17 genera and 23 species, including one new species - Stylosmil-ia xizangensis sp. nov. and six which are specifically indeterminable. Amongst them: Heliocoenia aff. etalloni and H. bandukidzea have been found from the Upper Jurassic in Azerbajan and Baingoin in northern Tibet, China. Heltocoenia orbignyi has been reported from the Upper Jurassic of Poland, Romania and Ge'gyai, northwestern Tibet, China. Isastraea bernensis is widely distributed in Late Jurassic limestones of Switzerland, France, Romania and Tingri in southern Tibet, China. Whereas Axosmilia sessilis occurs in the Middle Jurassic of Cutch, India, the Upper Jurassic of Germany and also at Baingoin in northern Tibet, China. Cryptocoenia octosepta is widely distribu- ted occurring in Switzerland, Georgia and Baingoin, northern Tibet, China. The geological range of genus Dermosmilia is from Jurassic to

  11. Chemo- and biostratigraphy of the Late Jurassic from the Lower Saxony Basin, Northern Germany

    Science.gov (United States)

    Erbacher, Jochen; Luppold, Friedrich Wilhelm; Heunisch, Carmen; Heldt, Matthias; Caesar, Sebastian

    2013-04-01

    The upper Jurassic (Oxfordian to Tithonian) sediments of the Lower Saxony Basin (Northern Germany) comprises a succession of limestones, marlstones and claystones deposited in a shallow marine to lacustrine epicontinental basin situated between the Tethys and the Sub-Boreal seas. Both, the depositional environment and the palaeogeographically isolated position strongly compromise a chronostratigraphic dating of the regional lithostratigraphical and biostratigraphical units. In order to obtain a stratigraphic standard section for the Late Jurassic of the Lower Saxony Basin we drilled a 325 m long core (Core Eulenflucht 1) covering the lower part of the Berriasian (Wealden 2-3 of the Bückeburg Formation) to the lower Oxfordian (Heersum Formation). A compilation with a section outcropping in an active quarry 2 km north of the drill site resulted in a 340 m long section reaching down to the late Callovian (Ornatenton Formation) . Ammonites have only been described in the lowermost, Callovian part of the section. Investigations of benthic foraminifers, ostracods as well as palynology, however, allowed for a rather detailed biozonation of the core. These data indicate the stratigrapical completeness of the section when compared to the regional stratigraphic data of the Lower Saxony Basin. Due to the lack of ammonites in Late Jurassic part of the section, which would have allowed for a correlation with Tethyan successions, high resolution stable carbon isotope data have been produced from bulk rock carbonate. Even though most of the data derive from shallow marine, rather coarse grained carbonates, such as ooliths and floatstones the resulting carbon isotope curve is surprisingly clean with only little "noise" in the upper part (early Tithonian?) of the measured succession. The curve clearly shows some distinctive features reported from biostratigraphically well-dated carbon isotope records of the Northern Tethys (e.g. Bartolini et al., 2003, Padden et al., 2002, Rais et

  12. Enceladus and Tethys: Ultraviolet clues to surface composition & surface processing

    Science.gov (United States)

    Hendrix, Amanda R.; Hansen, Candice; Cassidy, Timothy A.; Royer, Emilie M.; Esposito, Larry W.; Holsclaw, Gregory

    2016-10-01

    Cassini's Ultraviolet Imaging Spectrograph (UVIS) is sensitive to the uppermost portion of the regoliths of the icy Saturnian moons, where interactions with E-ring grains and plasma processing are important. Organics are present in at least 30% of E ring grains (Postberg et al., 2008) and are likely transported to the surfaces of the satellites orbiting Saturn within the E ring. Plasma bombardment on the trailing hemispheres of the satellites can further process these organic species. Enceladus' surface exhibits visible color variations (Schenk et al., 2011), evidence of plume fall-out zones and zones where plume fall-out is not as heavy (and where E ring grain bombardment dominates). In this study, we investigate far-UV spectral and photometric differences in the Enceladus plume fallout and non-fallout regions to study compositional and structural differences, and we also study compositional and photometric variations in regions on Tethys' trailing and leading hemispheres to understand spectral effects of organics, E ring bombardment and plasma bombardment.

  13. Zircon U?Pb ages in Myanmar: Magmatic?metamorphic events and the closure of a neo-Tethys ocean?

    Science.gov (United States)

    Mitchell, Andrew; Chung, Sun-Lin; Oo, Thura; Lin, Te-Hsien; Hung, Chien-Hui

    2012-08-01

    part of a Western Myanmar block separated in the Jurassic from the Shan Plateau to the east by the southwestward continuation of the Bangong-Nujiang-Luxi neo-Tethys I ocean. We relate most intrusive and metamorphic events in and near the MMB to westward subduction of this ocean and end-Jurassic collision of the Plateau with the overriding Western Myanmar-Slate belt block; to orogenic polarity reversal and early Cretaceous westward translation of the Plateau sequence over the suture zone; and to eastward subduction of the ancestral Indian Ocean or neo-Tethys II beneath Myanmar with generation of the Wuntho-Popa arc beginning before the late Cretaceous. The MMB includes meta-Plateau rocks near Mandalay but meta-Slate belt rocks to the north and south. Within the MMB, previous monazite-xenotime-thorite ages of Eocene-Oligocene, and Oligocene-early Miocene cooling ages on micas, with no deformation in Eocene granites, suggest a high-temperature thermal event related to intrusion of these and other granites during a previously proposed regional extension. Our data imply that the main fabric-forming metamorphic event in the MMB pre-dated the India-Asia collision.

  14. Tethys: The Marine and Hydrokinetic Technology Environmental Impacts Knowledge Management System -- Requirements Specification -- Version 1.0

    Energy Technology Data Exchange (ETDEWEB)

    Butner, R. Scott; Snowden-Swan, Lesley J.; Ellis, Peter C.

    2010-11-09

    The marine and hydrokinetic (MHK) environmental impacts knowledge management system (KMS), dubbed Tethys after the mythical Greek goddess of the seas, is being developed for the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy Wind and Hydropower Technologies Program (WHTP) by Pacific Northwest National Laboratory (PNNL). This requirements specification establishes the essential capabilities required of Tethys and clarifies for WHTP and the Tethys development team the results that must be achieved by the system.

  15. Geochemistry and petrogenesis of Mashhad granitoids: An insight into the geodynamic history of the Paleo-Tethys in northeast of Iran

    Science.gov (United States)

    Mirnejad, H.; Lalonde, A. E.; Obeid, M.; Hassanzadeh, J.

    2013-06-01

    hybridized in the mantle wedge with peridotite melt. The quartz diorite-tonalite-granodiorite stock and granodiorite batholith could be considered as arc-related granitoid intrusions, which were emplaced during the northward subduction of Paleo-Tethys Ocean crust beneath the Turan micro-continent. The monzogranite is strongly peraluminous (Al2O3/(CaO + Na2O + K2O) Mol. = 1.07-1.17), alkali-rich with normative corundum ranging between 1.19% and 2.37%, has high initial 87Sr/86Sr ratios (0.707457-0.709710) and low initial 143Nd/144Nd ratios (0.512042-0.512111) and ɛNd(t) values (- 5.3 to - 6.6) that substantiate with geochemical attributes of S-type granites formed by dehydration-melting of heterogeneous metasedimentary assemblages in thickened lower continental crust. The monzogranite was emplaced as a consequence of high-temperature metamorphism during the final integration of Turan and Iran plates. The ages found in the Mashhad granites show that the subduction of Paleo-Tethys under the Turan plate that led to the generation of arc-related Mashhad granites in late-Triassic, finally ceased due to the collision of Iran and Turan micro-plates in early Jurassic.

  16. Assimilation of Sea Surface Temperature in a doubly, two-way nested primitive equation model of the Ligurian Sea

    Science.gov (United States)

    Barth, A.; Alvera-Azcarate, A.; Rixen, M.; Beckers, J.-M.; Testut, C.-E.; Brankart, J.-M.; Brasseur, P.

    2003-04-01

    The GHER 3D primitive equation model is implemented with three different resolutions: a low resolution model (1/4^o) covering the whole Mediterranean Sea, an intermediate resolution model (1/20^o) of the Liguro-Provençal basin and a high resolution model (1/60^o) simulating the fine mesoscale structures in the Ligurian Sea. Boundary conditions and the averaged fields (feedback) are exchanged between two successive nesting levels. The model of the Ligurian Sea is also coupled with the assimilation package SESAM. It allows to assimilate satellite data and in situ observations using the local adaptative SEEK (Singular Evolutive Extended Kalman) filter. Instead of evolving the error space by the numerically expensive Lyapunov equation, a simplified algebraic equation depending on the misfit between observation and model forecast is used. Starting from the 1st January 1998 the low and intermediate resolution models are spun up for 18 months. The initial conditions for the Ligurian Sea are interpolated from the intermediate resolution model. The three models are then integrated until August 1999. During this period AVHRR Sea Surface Temperature of the Ligurian Sea is assimilated. The results are validated by using CTD and XBT profiles of the SIRENA cruise from the SACLANT Center. The overall objective of this study is pre-operational. It should help to identify limitations and weaknesses of forecasting methods and to suggest improvements of existing operational models.

  17. Study of the seasonal cycle of the biogeochemical processes in the Ligurian Sea using a 1D interdisciplinary model

    NARCIS (Netherlands)

    Raick, C.; Delhez, E.J.M.; Soetaert, K.E.R.; Grégoire, M.

    2005-01-01

    A one-dimensional coupled physical–biogeochemical model has been built to study the pelagic food web of the Ligurian Sea (NW Mediterranean Sea). The physical model is the turbulent closure model (version 1D) developed at the GeoHydrodynamics and Environmental Laboratory (GHER) of the University of L

  18. Application of an Ensemble Kalman filter to a 1-D coupled hydrodynamic-ecosystem model of the Ligurian Sea

    NARCIS (Netherlands)

    Lenartz, F.; Raick, C.; Soetaert, K.E.R.; Grégoire, M.

    2007-01-01

    The Ensemble Kalman filter (EnKF) has been applied to a 1-D complex ecosystem model coupled with a hydrodynamic model of the Ligurian Sea. In order to improve the performance of the EnKF, an ensemble subsampling strategy has been used to better represent the covariance matrices and a pre-analysis st

  19. Post-Jurassic tectonic evolution of Southeast Asia

    Science.gov (United States)

    Zahirovic, Sabin; Seton, Maria; Dietmar Müller, R.; Flament, Nicolas

    2014-05-01

    The accretionary growth of Asia, linked to long-term convergence between Eurasia, Gondwana-derived blocks and the Pacific, resulted in a mosaic of terranes for which conflicting tectonic interpretations exist. Here, we propose solutions to a number of controversies related to the evolution of Sundaland through a synthesis of published geological data and plate reconstructions that reconcile both geological and geophysical constraints with plate driving forces. We propose that West Sulawesi, East Java and easternmost Borneo rifted from northern Gondwana in the latest Jurassic, collided with an intra-oceanic arc at ~115 Ma and subsequently sutured to Sundaland by 80 Ma. Although recent models argue that the Southwest Borneo core accreted to Sundaland at this time, we use volcanic and biogeographic constraints to show that the core of Borneo was on the Asian margin since at least the mid Jurassic. This northward transfer of Gondwana-derived continental fragments required a convergent plate boundary in the easternmost Tethys that we propose gave rise to the Philippine Archipelago based on the formation of latest Jurassic-Early Cretaceous supra-subduction zone ophiolites on Halmahera, Obi Island and Luzon. The Late Cretaceous marks the shift from Andean-style subduction to back-arc opening on the east Asian margin. Arc volcanism along South China ceased by ~60 Ma due to the rollback of the Izanagi slab, leading to the oceanward migration of the volcanic arc and the opening of the Proto South China Sea (PSCS). We use the Apennines-Tyrrhenian system in the Mediterranean as an analogue to model this back-arc. Continued rollback detaches South Palawan, Mindoro and the Semitau continental blocks from the stable east Asian margin and transfers them onto Sundaland in the Eocene to produce the Sarawak Orogeny. The extrusion of Indochina and subduction polarity reversal along northern Borneo opens the South China Sea and transfers the Dangerous Grounds-Reed Bank southward to

  20. Paleoenvironmental conditions across the Jurassic-Cretaceous boundary in central-eastern Mexico

    Science.gov (United States)

    Martínez-Yáñez, Mario; Núñez-Useche, Fernando; López Martínez, Rafael; Gardner, Rand D.

    2017-08-01

    The Padni section of central-eastern Mexico is characterized by pelagic, organic-rich carbonates and shales dated in this study by calpionellid biostratigraphy to the late Tithonian-late Berriasian time interval. Microfacies, pyrite framboid size, spectrometric gamma-ray and mineralogical data are herein integrated in order to reconstruct the paleoenvironmental change during the Jurassic-Cretaceous boundary. Deposits of the late Tithonian-early Berriasian are characterized by laminated, organic-rich facies with abundant radiolarian, tiny pyrite framboids and low Th/U ratios. They are linked to upwelling in a semi-restricted basin, high marine productivity and anoxic bottom waters. The early incursions of Tethyan oceanic waters into the proto-Gulf of Mexico occurred during late Tithonian as attested the appearance of calpionellids. Short and intermittent accumulations of saccocomids during early Berriasian suggest episodes of sporadic connection between the Tethys, the proto-Atlantic and the Pacific ocean during sea-level rise events. A full and stable connection between the Tethys and proto-Gulf of Mexico was established until the late Berriasian. This event is supported by the presence of open marine and bioturbated facies with a framboid population typical of dysoxic conditions, higher Th/U ratios and a decreasing pattern of the total organic carbon content. In addition to highlighting the replenishment of the oxygen supply to the basin, this facies also points to a younger age for the finalization of the Yucatán Block rotation and the end of the Gulf of Mexico opening. Deposition of the studied section occurred mostly during a Tithonian-Berriasian arid phase reported in other Tethyan and Atlantic regions. The similarity between the discrete segments of the standard gamma-ray curve defined in the studied outcrop and those reported from subsurface implies their regional continuity allowing their use for correlation purposes.

  1. Aalenian foraminiferal fauna and microfacies analyses of the Tethys Ocean Basin from the Transdanubian Range (Hungary)

    Science.gov (United States)

    Zsiborás, Gábor; Görög, Ágnes

    2016-04-01

    The early Middle Jurassic foraminiferal fauna of the Tethys Ocean Basin is hardly known. It is especially true for the Aalenian from when only Monaco et al. (1994) published some forms from Valdorbia Section, Central Italy and Wernli (1988) from Domuz Dag, Turkey. Thus the aim of our study was to give a detailed systematic description of the foraminiferal fauna and microfacies analyses of Nagy-Pisznice Section of Lábatlan and T?zköves Gorge of Bakonycsernye from the Transdanubian Range. According to several studies of Géczy} and others, the ammonite fauna indicate all Aalenian (Opalinum, Murchisonae, Concavum) biozones in both successions. 6 samples from T?zköves Gorge, 13 samples from Nagy-Pisznice were collected. Both sequences are about 3 metres thick Ammonitico Rosso type reddish grey limestone with flaser beds and nodules (Tölgyhát Limestone Formation). For the microfacies studies thin sections were made. The dominant microfacies is bioclastic wackestone predominated {Bositra} shells. To extract the microfossils, each sample was dissolved in glacial acetic acid. The microfauna consist of foraminifers, calcispheres, juvenile ammonites, ostracods, radiolarians, microgastropods and fragments of echinoderms. Throughout the Nagy-Pisznice succession, the composition of the foraminiferal fauna is relatively uniform and moderately divers. Most specimens belong to Suborder Lagenina with 60-80{%} abundance. The Suborder Spirillinina are also frequent with 20-35{%} abundance. Agglutinants are subordinated and Suborder Miliolina is absent. The most abundant genus is {Lenticulina}, its amount is more than 50{%} in some samples. {Astacolus}, {Marginulina}, {Dentalina}, {Nodosaria}, {Paralingulina} and Epistominidae are also frequent. {Eoguttulina} and {Paalzowella} are scarce. Spirillinids are represented by {Spirillina}, {Turrispirillina}, and {Coronipora} genera. The taxonomic composition of the foraminiferal fauna of T?zköves Gorge is similar to the aforesaid

  2. Petrotectonic Evolution of Paleo-Tethys in Western Yunnan,China

    Institute of Scientific and Technical Information of China (English)

    从柏林; 吴根耀; 张旗; 张儒媛; 翟明国; 赵大升; 张雯华

    1994-01-01

    The Western Yunnan is just situated in juncture area of the Yangtze,Indosinia and Shan-Thai Microcontinents,with the geosuture zones among them marked by ophiolite suites and blue schists.Agreat number of petrological data support systematic evidences for Paleo-Tethys occurring in the area,andaccording to them,the tectonic evolution is reconstructed.Paleo-Tethys might be a poly-island ocean duringthe Late Paleozoic,and relic oceanic basins developed in Triassic1 Neo-Tethys immigrated westwards intoBurma.The area is an orogenic belt experiencing complicated subduction and violent continent-continent col-lision,and reformed by the younger structures,specially the Himalayan movement.

  3. Underwater acoustic evidences of the 2011 autumnal floods in the Ligurian region

    Science.gov (United States)

    Anagnostou, Marios; Pensieri, Sara; Bozzano, Roberto; Anagnostou, Emmanouil; Bechini, Renzo; Nystuen, Jeffry

    2013-04-01

    In the northernmost sector of the western Mediterranean Sea the Ligurian Sea is a deep basin showing peculiar hydrodynamic and meteo-oceanographic features. The region is characterized by steep Alpine and Apennine southward slopes with the watershed at few tens of kilometers at the most far from the coast. This geological complexity and a particular atmospheric circulation coupled to the fact that the Ligurian coasts are among the most urbanized and industrialized along the entire Mediterranean coastline, determine a high flood hazard, especially in late summer - early autumn when the Ligurian Sea is still warm and strong perturbations reach the basin from the south. Over the past 40 years there have been about 40 major flash floods (about one flash flood per year) associated with severe damages and loss of human lives. The latest flash flood event occurred in Autumn 2011, which is the subject matter of this study. Late summer 2011 was dominated, as usual in the recent decades, by a prolongation of the hot season with clear skies and temperatures above climatology so that ocean had sufficient time to store a large amount of heat capable of emitting a strong evaporation in the air layers above and, through interactions with the cool and wet near surface atmospheric layers, to give rise to powerful convection. Such type of events can be partially forecasted by atmospheric models, monitored at a large scale through remote sensing using radars and satellites, observed in their real time evolution by land hydro-meteorological stations. Among other observational systems, underwater acoustics can contribute to the monitoring of these phenomena through the use of off-shore deployed sensors that collect and process underwater noise in the ocean. Indeed, ambient noise in the ocean is a combination of natural and anthropogenic sounds that include breaking waves, precipitation, vocalizations of marine mammals, ship noise and sonar. Since 2009, a Passive Aquatic Listener (PAL

  4. Back arc extension, tectonic inheritance, and volcanism in the Ligurian Sea, Western Mediterranean

    Science.gov (United States)

    Rollet, Nadège; Déverchère, Jacques; Beslier, Marie-Odile; Guennoc, Pol; Réhault, Jean-Pierre; Sosson, Marc; Truffert, Catherine

    2002-06-01

    The Ligurian basin, western Mediterranean Sea, has opened from late Oligocene to early Miocene times, behind the Apulian subduction zone and partly within the western Alpine belt. We analyze the deep structures of the basin and its conjugate margins in order to describe the tectonic styles of opening and to investigate the possible contributions of forces responsible for the basin formation, especially the pulling force induced by the retreating subduction hinge and the gravitational body force from the Alpine wedge. To undertake this analysis, we combine new multichannel seismic reflection data (Malis cruise, 1995) with other geophysical data (previous multichannel and monochannel seismic sections, magnetic anomalies) and constrain them by geological sampling from two recent cruises (dredges from Marco cruise, 1995, and submersible dives from Cylice cruise, 1997). From an analysis of basement morphology and seismic facies, we refine the extent of the different domains in the Ligurian Sea: (1) the continental thinned margins, with strong changes in width and structure along strike and on both sides of the ocean; (2) the transitional domain to the basin; and (3) a narrow, atypical oceanic domain. Margin structures are characterized by few tilted blocks along the narrow margins, where inherited structures seem to control synrift sedimentation and margin segmentation. On the NW Corsican margin, extension is distributed over more than 120 km, including offshore Alpine Corsica, and several oceanward faults sole on a relatively flat reflector. We interpret them as previous Alpine thrusts reactivated during rifting as normal faults soling on a normal ductile shear zone. Using correlations between magnetic data, seismic facies, and sampling, we propose a new map of the distribution of magmatism. The oceanic domain depicts narrow, isolated magnetic anomalies and is interpreted as tholeitic volcanics settled within an unroofed upper mantle, whereas calcalkaline volcanism

  5. Modeling jellyfish Pelagia noctiluca transport and stranding in the Ligurian Sea.

    Science.gov (United States)

    Berline, L; Zakardjian, B; Molcard, A; Ourmières, Y; Guihou, K

    2013-05-15

    Jellyfish blooms are generally attributed to a biological response to the environment, neglecting the role of transport patterns in redistributing existing populations. Here, we use high-resolution (1.25km) ocean modeling to examine the role of transport in the onshore arrival and abundance of the pelagic stinging jellyfish Pelagia noctiluca on the Ligurian Sea coast. Jellyfish are modeled as Lagrangian particles with a 0-300-m diel vertical migration typical of P. noctiluca. Over the course of a year, onshore arrivals are not restricted to the summer. Arrivals are concentrated at capes, but abundance can reach maxima in bays and in the lee of capes. Two factors impact jellyfish arrivals at the coast: the position of the Northern Current and the wind. A comparison of summer 2006 and available onshore jellyfish observations suggests a correct capture of the main stranding events by the model. These results have implications for understanding long-term fluctuations.

  6. Census of Ligurian Internal Medicine Wards of non-teaching hospitals

    Directory of Open Access Journals (Sweden)

    Micaela La Regina

    2014-12-01

    Full Text Available What is the future of internal medicine in Italy? Which competencies? Which potentialities? To this aim Ligurian FADOI Regional Society performed a census among 18 Internal Medicine Wards (IMWs in non-teaching Ligurian Hospital. We administered, by email, a questionnaire to the heads of IMWs. Data about staffing, equipment, skills, competencies and productivity during 2011 were collected from 1st to 31st November 2012. A total of 15/18 (83.3% chiefs answered to the questionnaire. The number of beds was largely variable among the wards. In 2011, mean diagnosis-related group (DRG-weight was 1.09 (range 0.91-1.6 and that revenues/costs ratio much higher than 1.5. Staff was quite adequate to standards defined by current law, only 33% has got a doctor:patients ratio superior to 1:6.4. However, annual hospitalizations exceed the availability of beds in medicine and the complexity of the patients would require a lower doctor:patients ratio, at least for a group of patients. In fact, 4 wards have a progressive care organization with a defined area for more seriously ill patients. Mean length of stay was 10 days. Expertise was wide, covering almost all medical sub-specialties. Acquired skills such as abdominal, heart and vascular ultrasounds, invasive procedures and their comprehensive knowledge make internists complete and cost-effective specialists. IMWs, as a concentrate of medical knowledge and skills, are the natural destination of current patients with co-morbidities. Staffing and number of beds should be revised according to this new demand. Their revenues/costs ratio resulted favorable and their global approach to patients and not to disease can be useful for resource rationalization. Wider and further studies are needed to improve the awareness of stakeholders about Internal Medicine.

  7. Tectonic Evolution of the Jurassic Pacific Plate

    Science.gov (United States)

    Nakanishi, M.; Ishihara, T.

    2015-12-01

    We present the tectonic evolution of the Jurassic Pacific plate based on magnetic anomly lineations and abyssal hills. The Pacific plate is the largest oceanic plate on Earth. It was born as a microplate aroud the Izanagi-Farallon-Phoenix triple junction about 192 Ma, Early Jurassic [Nakanishi et al., 1992]. The size of the Pacific plate at 190 Ma was nearly half that of the present Easter or Juan Fernandez microplates in the East Pacific Rise [Martinez et at, 1991; Larson et al., 1992]. The plate boundary surrounding the Pacific plate from Early Jurassic to Early Cretaceous involved the four triple junctions among Pacific, Izanagi, Farallon, and Phoenix plates. The major tectonic events as the formation of oceanic plateaus and microplates during the period occurred in the vicinity of the triple junctions [e.g., Nakanishi and Winterer, 1998; Nakanishi et al., 1999], implying that the study of the triple junctions is indispensable for understanding the tectonic evolution of the Pacific plate. Previous studies indicate instability of the configuration of the triple junctions from Late Jurassic to Early Cretaceous (155-125 Ma). On the other hand, the age of the birth of the Pacific plate was determined assuming that all triple junctions had kept their configurations for about 30 m.y. [Nakanishi et al., 1992] because of insufficient information of the tectonic history of the Pacific plate before Late Jurassic.Increase in the bathymetric and geomagnetic data over the past two decades enables us to reveal the tectonic evolution of the Pacific-Izanagi-Farallon triple junction before Late Jurassic. Our detailed identication of magnetic anomaly lineations exposes magnetic bights before anomaly M25. We found the curved abyssal hills originated near the triple junction, which trend is parallel to magnetic anomaly lineations. These results imply that the configuration of the Pacific-Izanagi-Farallon triple junction had been RRR before Late Jurassic.

  8. Palaeo-equatorial temperatures and carbon-cycle evolution at the Triassic- Jurassic boundary: A stable isotope perspective from shallow-water carbonates from the UAE

    Science.gov (United States)

    Honig, M. R.; John, C. M.

    2013-12-01

    The Triassic-Jurassic boundary was marked by global changes including carbon-cycle perturbations and the opening of the Atlantic Ocean. These changes were accompanied by one of the major extinction events of the Phanerozoic. The carbon-cycle perturbations have been recorded in carbon isotope curves from bulk carbonates, organic carbon and fossil wood in several Tethyan locations and have been used for chemostratigraphic purposes. Here we present data from shallow-marine carbonates deposited on a homoclinal Middle Eastern carbonate ramp (United Arab Emirates). Our site was located at the equator throughout the Late Triassic and the Early Jurassic, and this study provides the first constraints of environmental changes at the low-latitudes for the Triassic-Jurassic boundary. Shallow-marine carbonate depositional systems are extremely sensitive to palaeoenvironmental changes and their usefulness for chemostratigraphy is being debated. However, the palaeogeographic location of the studied carbonate ramp gives us a unique insight into a tropical carbonate factory at a time of severe global change. Stable isotope measurements (carbon and oxygen) are being carried out on micrite, ooids and shell material along the Triassic-Jurassic boundary. The stable isotope results on micrite show a prominent negative shift in carbon isotope values of approximately 2 ‰ just below the inferred position of the Triassic-Jurassic boundary. A similar isotopic trend is also observed across the Tethys but with a range of amplitudes (from ~2 ‰ to ~4 ‰). These results seem to indicate that the neritic carbonates from our studied section can be used for chemostratigraphic purposes, and the amplitudes of the carbon isotope shifts provide critical constraints on the magnitude of carbon-cycle perturbations at low latitudes across the Triassic-Jurassic boundary. Seawater temperatures across the Triassic-Jurassic boundary will be constrained using the clumped isotope palaeo-thermometer applied

  9. Middle Jurassic shear zones at Cap de Creus (eastern Pyrenees, Spain) : a record of pre-drift extension of the Piemonte–Ligurian Ocean?

    NARCIS (Netherlands)

    Vissers, Reinoud L. M.; Van Hinsbergen, Douwe J. J.; Wilkinson, Camilla M.; Ganerød, Morgan

    2017-01-01

    The Cap de Creus peninsula in NE Spain consists of greenschist- to amphibolite-facies metasediments and granitoid bodies of the Variscan Axial Zone of the Pyrenees, overprinted in the north by anastomosed greenschist-facies shear zones. Current tectonic interpretations ascribe these shear zones to t

  10. Correction of inertial oscillations by assimilation of HF radar data in a model of the Ligurian Sea

    Science.gov (United States)

    Vandenbulcke, Luc; Beckers, Jean-Marie; Barth, Alexander

    2016-11-01

    This article aims at analyzing if high-frequency radar observations of surface currents allow to improve model forecasts in the Ligurian Sea, where inertial oscillations are a dominant feature. An ensemble of ROMS models covering the Ligurian Sea, and nested in the Mediterranean Forecasting System, is coupled with two WERA high-frequency radars. A sensitivity study allows to determine optimal parameters for the ensemble filter. By assimilating observations in a single point, the obtained correction shows that the forecast error covariance matrix represents the inertial oscillations, as well as large- and meso-scale processes. Furthermore, it is shown that the velocity observations can correct the phase and amplitude of the inertial oscillations. Observations are shown to have a strong effect during approximately half a day, which confirms the importance of using a high temporal observation frequency. In general, data assimilation of HF radar observations leads to a skill score of about 30% for the forecasts of surface velocity.

  11. Correction of inertial oscillations by assimilation of HF radar data in a model of the Ligurian Sea

    Science.gov (United States)

    Vandenbulcke, Luc; Beckers, Jean-Marie; Barth, Alexander

    2017-01-01

    This article aims at analyzing if high-frequency radar observations of surface currents allow to improve model forecasts in the Ligurian Sea, where inertial oscillations are a dominant feature. An ensemble of ROMS models covering the Ligurian Sea, and nested in the Mediterranean Forecasting System, is coupled with two WERA high-frequency radars. A sensitivity study allows to determine optimal parameters for the ensemble filter. By assimilating observations in a single point, the obtained correction shows that the forecast error covariance matrix represents the inertial oscillations, as well as large- and meso-scale processes. Furthermore, it is shown that the velocity observations can correct the phase and amplitude of the inertial oscillations. Observations are shown to have a strong effect during approximately half a day, which confirms the importance of using a high temporal observation frequency. In general, data assimilation of HF radar observations leads to a skill score of about 30% for the forecasts of surface velocity.

  12. Shear in the tethys and the permian paleomagnetism in the Southern Alps, including new results

    NARCIS (Netherlands)

    Zijderveld, J.D.A.; Hazeu, G.J.A.; Nardin, M.; Voo, R. van der

    1970-01-01

    To verify paleomagnetic proof for megatectonic translation in the Tethys a large collection of samples from a key area, the Bolzano Quartz Porphyry Plateau in the Southern Alps, was examined. Their natural remanent magnetization was analyzed with thermal, and mainly alternating field demagnetization

  13. Wann löste sich das Gebiet des Indischen Archipels von der Tethys? (eine Fortsetzung)

    NARCIS (Netherlands)

    Martin, K.

    1931-01-01

    Die vorstehende Frage versuchte ich schon im Jahre 1914 zu beantworten 1). Dabei gelangte ich zu diesem Ergebnis: „Zar Zeit der Entstehung der eocänen Ablagerungen von Nanggulan...... war das Gebiet des jetzigen Java vollständig von der Tethys losgelöst und seitdem ist die Verbindung mit letzterer a

  14. Behavioral Responses of Nave Cuvier’s Beaked Whales in the Ligurian Sea to Playback of Anthropogenic and Natural Sounds

    Science.gov (United States)

    2015-09-30

    unimpeded during all experimental phases. Figure 1. Map of Mediterranean Sea with expanded inset of the Ligurian Sea study area . Black spot indicates...from the home port of Savona. However, when these areas were searched, no visual or acoustic detections of Ziphius were made. Sightings reported by...twelve animals were successfully photo-documented: five adult females, three immature, two juveniles , one adult male and one subadult male. Of these

  15. Analysis of surface circulation structures along a frequently repeated XBT transect crossing the Ligurian and Tyrrhenian Seas

    Science.gov (United States)

    Ciuffardi, Tiziana; Napolitano, Ernesto; Iacono, Roberto; Reseghetti, Franco; Raiteri, Giancarlo; Bordone, Andrea

    2016-07-01

    A dataset of XBT (eXpendable BathyThermograph) temperature profiles collected by ships of opportunity along the Genova-Palermo route, since September 1999, is analyzed, together with altimetric observations and model results, with the purpose of identifying and characterizing robust circulation features along the track and investigating their variability. An anticyclone is found in the Ligurian Sea, just north of the Corsica Channel, not present in previous descriptions of the Mediterranean Sea circulation. It appears to be a recurrent feature, better defined and stronger in summer and in the beginning of autumn. In the northern part of the Tyrrhenian Sea, the well-known Bonifacio dipole shows a similar seasonality, in agreement with previous observations. However, the Bonifacio anticyclone also displays a strong interannual variability, not previously recorded, with significant variations in position and shape. In fact, the data suggest the existence of two distinct summer circulation regimes related to the position and shape of the Ligurian anticyclone. When the latter is wider, filling the entire region north of the Corsica Channel, the circulation in the northern Tyrrhenian Sea is isolated from that in the Ligurian Sea, in agreement with the common picture. However, the altimeter maps show that there are several cases in the last two decades in which the Ligurian anticyclone is small and displaced to the west, allowing an inflow through the Corsica Channel into the Tyrrhenian Sea. The two regimes appear to result from a delicate balance between the forcings acting in the two sub-basins and the topographic constraints.

  16. Early Jurassic foraminiferal assemblages in platform carbonates of Mt. Krim, central Slovenia

    Directory of Open Access Journals (Sweden)

    Luka Gale

    2017-06-01

    Full Text Available During the Early Jurassic, the subtropical carbonate platforms of the peri-Tethys Ocean experienced signifiant changes in their architectures, as well as in their biota compositions. Shallow-water carbonates from the northern part of the ancient Adriatic Carbonate Platform (External Dinarides were investigated in six sections, which taken together cover the development of the platform from deposition of the uppermost Triassic Main Dolomite to the middle Lower Jurassic, lithiotid limestone. Our aim was to establish a detailed foraminiferal biostratigraphy and to observe the changes in size, abundance and diversity of foraminifera in different types of facies. As a result, the succession was successfully divided into stage or substage levels. Foraminiferal assemblages were shown to experience a gradual change in taxonomic composition (including an increase in the proportion of complex agglutinated forms, a general increase in abundance of specimens, and greater diversity in each facies type, except in bindstone and mudstone. Notable is the difference between Hettangian assemblages, which display fairly uniform compositions in all facies types and the predominance of opportunists, and the post-Hettangian assemblages, which become progressively more species-rich and where the differences in facies are perhaps more pronounced. Changes in the size of the species Meandrovoluta asiagoensis Fugagnoli & Rettori, and of the largest specimen in the assemblages, however, are less clear, but are arguably present. Faunal changes roughly correspond to the gradual change from the flt-top platform of the upper Triassic – Hettangian, where biota would be repeatedly subjected to stressed peritidal conditions, to a platform differentiated into lagoon, sand bars and ephemeral emergent areas, offering numerous habitats and perhaps more stable living conditions for organisms.

  17. Sedimentary organic matter characterization of the Triassic-Jurassic boundary GSSP at Kuhjoch (Austria)

    Science.gov (United States)

    Ruhl, M.; Veld, H.; Kürschner, W. M.

    2010-03-01

    The Triassic-Jurassic (T-J) boundary interval coincides with enhanced extinction rates in the marine realm and pronounced changes in terrestrial ecosystems on the continents. It is further marked by distinct negative excursions in the δ13C org and δ13C carb signature that may represent strong perturbations of the global carbon cycle. We present integrated geochemical, stable-isotope and palynological data from the Kuhjoch section, the Global boundary Stratotype Section and Point (GSSP) for the base of the Jurassic (Northern Calcareous Alps, Austria). We show that the initial carbon isotope excursion (CIE), coinciding with the marine extinction interval and the formation of black shales in the western Tethys Eiberg Basin, is marked by only minor changes in kerogen type, which is mainly of terrestrial origin. Increased Total Organic Carbon (TOC) concentrations of 9% at the first half of the initial CIE coincide with Hydrogen Index (HI) values of over 600 mg HC/g TOC. The high correlation (with R2 = 0.93) between HI values and terrestrial Cheirolepidiaceaen conifer pollen suggests a terrestrial source for the hydrogen enriched organic compounds. The lack of major changes in source of the sedimentary organic matter suggests that changes in the δ13C org composition are genuine and represent true disturbances of the global C-cycle. The sudden decrease in total inorganic carbon (TIC) concentrations likely represents the onset of a biocalcification crisis. It coincides with a 4.5‰ negative shift in δ13C org values and possibly corresponds to the onset of CAMP related volcanic activity. The second half of the initial CIE is marked by the dramatic increase of green algae remains in the sediment. The simultaneous increase of the C org/N tot ratio suggests increased marine primary production at the final stage of black shale formation.

  18. Pangaean climate during the Early Jurassic: GCM simulations and the sedimentary record of paleoclimate

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, M.A. [Columbia Univ., Palisades, NY (United States); Rind, D.; Ruedy, R. [Goddard Institute for Space Studies, New York, NY (United States)

    1992-05-01

    Results from new simulations of the Early Jurassic climate show that increased ocean heat transport may have been the primary force generating warmer climates during the past 180 m.y. The simulations, conducted using the general circulation model (GCM) at the Goddard Institute for Space Studies, include realistic representations of paleocontinental distribution, topography, epeiric seas, and vegetation, in order to facilitate comparisons between model results and paleoclimate data. three major features of the simulated Early Jurassic climate include the following. (1) A global warming, compared to the present, of 5 {degrees}C to 10 {degrees}C, with temperature increases at high latitudes five times this global average. Average summer temperatures exceed 35 {degrees}C in low-latitude regions of western Pangaea where eolian sandstones testify to the presence of vast deserts. (2) Simulated precipitation and evaporation patterns agree closely with the moisture distribution interpreted from evaporites, and coal deposits. High rainfall rates are associated primarily with monsoons that originate over the warm Tethys Ocean. Unlike the {open_quotes}megamonsoons{close_quotes} proposed in previous studies, these systems are found to be associated with localized pressure cells whose positions are controlled by topography and coastal geography. (3) Decreases in planetary albedo, occurring because of reductions in sea ice, snow cover, and low clouds, and increases in atmospheric water vapor are the positive climate feedbacks that amplify the global warming. Similar to other Mesozoic climate simulations, our model finds that large seasonal temperature fluctuations occurred over mid- and high-latitude continental interiors, refuting paleoclimate evidence that suggests more equable conditions. 101 refs., 9 figs., 3 tabs.

  19. The Upper Triassic alkaline magmatism of the western Neo-Tethys (Bajo Ebro, NE Spain): age and geodynamic implications

    Science.gov (United States)

    Sanz, T.; Lago, M.; Gil, A.; Pocoví, A.; Galé, C.; Ubide, T.; Larrea, P.; Ramajo, J.; Tierz, P.

    2012-04-01

    A set of mafic rocks crop out in the north-western margin of the Neo-Tethys (eastern Spain and France). These rocks show three common features: 1) they were emplaced into Upper Triassic sediments (Keuper facies), 2) they are mainly basalts and dolerites and show an alkaline geochemical affinity and 3) these magmas rose to their emplacement level through deep fractures; some of the fractures were newly opened as a result of the Triassic extension (Triassic-Liassic rifting), whereas others had been generated during the Permian extension (Lower Permian rifting) and were reopened. Magmatic activity has also been recognized in these areas during the Jurassic, the Cretaceous and the Quaternary. The Bajo Ebro sector (NE Spain) comprises two types of Upper Triassic mafic rocks: 1) massive rocks emplaced as dikes, sills and basaltic lavas (10-12 meters in thickness and up to kilometric in extension) and 2) a wide range of pyroclasts (from ash grains to bombs) forming layers more than 100 meters thick, which are usually interbedded with argillites and carbonates. Protrusions of the sills into the overlying sediments, together with spilitization of the igneous rocks, suggest that the magmas emplaced into unconsolidated sediments. Furthermore, a level of epiclastic-basaltic breccias is recognized overlying the magmatic levels and below the dolostones of the Imón Formation (Rhaetian in age); these breccias are interpreted to represent an erosive episode which affected the magmatic rocks in emerged areas. According to these criteria, these rocks can be considered Upper Triassic (pre-Rhaetian) in age. The basaltic lavas show alkaline mineral assemblages composed of: olivine (Fo79-65), Ti-rich clinopyroxene (Fs3-15, En52-35, Wo50-42), plagioclase (An80-50), Ti-rich magnetite and apatite. Their major and trace element whole rock compositions show contents in SiO2 (41,3-49,3 w.%), Nb/Y (1,5-4,1), Zr/TiO2 (0,0057-0,013), V (157,8-292,1 ppm) and Ti/1000 (11,3-18,53) which indicate

  20. The Ligurian Cluster for Marine Technologies (DLTM): matching local research and industrial needs on oceanographic data.

    Science.gov (United States)

    Stroobant, M.; Locritani, M.; Marini, D.; Sabbadini, L.; Carmisciano, C.; Manzella, G.; Magaldi, M.; Aliani, S.

    2012-04-01

    DLTM is the Ligurian Region (north Italy) cluster of Centre of Excellence (CoE) in waterborne technologies, that involves about 120 enterprises - of which, more than 100 SMEs -, the University of Genoa, all the main National Research Centres dealing with maritime and marine technologies established in Liguria (CNR, INGV, ENEA-UTMAR), the NATO Undersea Research Centre (NURC) and the Experimental Centre of the Italian Navy (CSSN), the Bank, the Port Authority and the Chamber of Commerce of the city of La Spezia. Following its mission, DLTM has recently established three Collaborative Research Laboratories focused on: 1. Computational Fluid dynamics (CFD_Lab) 2. High Performance Computing (HPC_Lab) 3. Monitoring and Analysis of Marine Ecosystems (MARE_Lab). The main role of them is to improve the relationships among the research centres and the enterprises, encouraging a systematic networking approach and sharing of knowledge, data, services, tools and human resources. Two of the key objectives of Lab_MARE are the establishment of: - an integrated system of observation and sea forecasting; - a Regional Marine Instrument Centre (RMIC) for oceanographic and metereological instruments (assembled using 'shared' tools and facilities). Besides, an important and innovative research project has been recently submitted to the Italian Ministry for Education, University and Research (MIUR). This project, in agreement with the European Directives (COM2009 (544)), is aimed to develop a Management Information System (MIS) for oceanographic and meteorological data in the Mediterranean Sea. The availability of adequate HPC inside DLTM is, of course, an important asset for achieving useful results; for example, the Regional Ocean Modeling System (ROMS) model is currently running on a high-resolution mesh on the cluster to simulate and reproduce the circulation within the Ligurian Sea. ROMS outputs will have broad and multidisciplinary impacts because ocean circulation affects the

  1. Dinosaur dynamics in the Jurassic Era

    Science.gov (United States)

    Lee, Scott

    2010-04-01

    Dinosaurs were fascinating animals and elicit much excitement in the classroom. Analysis of fossilized dinosaur trackways permits one to estimate the locomotion speeds and accelerations of these extinct beasts. Such analysis allows one to apply Newton's laws of motion to examples from the Jurassic Era.

  2. SICILIAN JURASSIC PHYSIOGRAPHY AND GEOLOGIC REALMS (ITALY

    Directory of Open Access Journals (Sweden)

    BENEDETTO ABATE

    2004-03-01

    Full Text Available Two tectono-sedimentary domains, which were deformed during the Neogene and evolved into two large structural sectors, characterize the Sicilian Jurassic: the Maghrebides and Peloritani. Africa margin sediments, passing downward to Triassic successions and perhaps originally to Paleozoic deposits, characterize the former. The latter belongs to the European "Calabrian Arc", where the Jurassic transgressively rests on a continental substrate (i.e. the crystalline Variscan basement. These domains are characterized by four sedimentary facies: shallow platform-derived limestones; condensed seamount-type red limestones; nodular limestones with ammonites; deep radiolarites and shales. These facies are illustrated in a dozen of stratigraphic logs. The drowning of most Triassic-Liassic carbonate platforms or ramps and the deepening of adjacent basins came with inferred Jurassic strike-slip tectonics, connected to the relative movement of Africa (Gondwanan part vs Europe (Laurasian part; the same strike-slip tectonics may have caused scattered intraplate volcanic seamounts found in Maghrebides. During the Jurassic the Maghrebide realm was characterized by the interfingering of basins and carbonate platforms. During the Early and Middle Liassic, carbonate platforms and ramps were dominant. Since Toarcian either radiolarites in some basins or Ammonite-bearing calcareous muds developed with intervening basaltic flows, and were accompanied by condensed pelagic carbonates on the ensialic seamount-type highs. The Peloritani realm displays similar characteristics, but with later transgression on the basement, several strike-slip basins and without any volcanoes.

  3. New Early Jurassic Tetrapod Assemblages Constrain Triassic-Jurassic Tetrapod Extinction Event

    Science.gov (United States)

    Olsen, P. E.; Shubin, N. H.; Anders, M. H.

    1987-08-01

    The discovery of the first definitively correlated earliest Jurassic (200 million years before present) tetrapod assemblage (Fundy basin, Newark Supergroup, Nova Scotia) allows reevaluation of the duration of the Triassic-Jurassic tetrapod extinction event. Present are tritheledont and mammal-like reptiles, prosauropod, theropod, and ornithischian dinosaurs, protosuchian and sphenosuchian crocodylomorphs, sphenodontids, and hybodont, semionotid, and palaeonisciform fishes. All of the families are known from Late Triassic and Jurassic strata from elsewhere; however, pollen and spore, radiometric, and geochemical correlation indicate an early Hettangian age for these assemblages. Because all ``typical Triassic'' forms are absent from these assemblages, most Triassic-Jurassic tetrapod extinctions occurred before this time and without the introduction of new families. As was previously suggested by studies of marine invertebrates, this pattern is consistent with a global extinction event at the Triassic-Jurassic boundary. The Manicouagan impact structure of Quebec provides dates broadly compatible with the Triassic-Jurassic boundary and, following the impact theory of mass extinctions, may be implicated in the cause.

  4. The ODAS Italia 1 buoy: More than forty years of activity in the Ligurian Sea

    Science.gov (United States)

    Canepa, Elisa; Pensieri, Sara; Bozzano, Roberto; Faimali, Marco; Traverso, Pierluigi; Cavaleri, Luigi

    2015-06-01

    The Ligurian Sea plays a relevant role in driving both the circulation of the Western Mediterranean Sea and the weather and climate of the area. In order to better understand the peculiarities of this basin, the Oceanographic Data Acquisition System (ODAS) Italia 1 buoy was developed and deployed in the early '70s. Throughout the years, the buoy has been fitted with updated measuring and data acquiring systems. Since 2003 the buoy has been part of the Mediterranean Moored Multi-sensor Array network of fixed open ocean observatories with the W1-M3A identifier and presently constitutes one of the Mediterranean sites of the European FixO3 network. Recently, a deep-ocean sub-surface mooring line was, and is, deployed close to it in relation to specific projects. This multidisciplinary observing system is able to perform both long-term operational and ad-hoc monitoring from the lower atmosphere to the deep ocean. It is used for analysis of air-sea interaction processes, study of the physical proprieties of the water column, bio-geo-chemical monitoring of the sea, meteorological and oceanographic model evaluation, calibration of remotely sensed measurements, and development of innovative marine monitoring technologies. After reporting some historical notes and the description of the observing system, this paper summarises and reviews the main oceanographic and atmospheric studies performed during the last 15 years using the data acquired on board.

  5. Depositional architecture and sequence stratigraphy of Pleistocene coarse-grained deltas along the Ligurian coast (Italy)

    Indian Academy of Sciences (India)

    A Ciampalini; M Firpo

    2015-12-01

    This study aims to develop a better understanding of the stratigraphy of the southern side of the Maritime Alps and of the Ligurian Sea during the Plio-Pleistocene. Five stratigraphic sections were measured and studied in the Segno River valley (Liguria, Italy). These sections are composed of Lower to Middle Pleistocene marine and continental deposits. Based on detailed mapping and sedimentological analysis, 12 marine and deltaic facies were identified. These facies were grouped into facies associations. Two allostratigraphic units were recognized, namely U1 and U2 from oldest to youngest. The lower unit (U1) represents the evolution of a coarse-grained delta developed in a valley or embayment. Within the deltaic sequence, transgressive and highstand systems tracts were recognized. The coarsening/shallowing upward trend observed within the sections suggests that the delta prograded rapidly in the landward portion of the canyon adjacent to the paleo-river outlet. The upper boundary of U1 is represented by a subaerial unconformity overlain by U2, which is composed of sediments deposited by several alluvial fan systems.

  6. Characterization and cartography of some Mediterranean soft-bottom benthic communities (Ligurian Sea, Italy

    Directory of Open Access Journals (Sweden)

    A. Somaschini

    1998-06-01

    Full Text Available Soft-bottom benthic communities were studied along the Western coast of the Ligurian Sea with a new approach using both videocamera surveys and collected samples. The preliminary distribution of soft-bottoms and the definition of the limits and status of seagrass beds were carried out in September 1991, using an underwater vehicle provided with a videocamera and towed by a boat. Moreover, 90 benthic samples were collected at 5-40 m depth in order to characterize the macrobenthic soft-bottom communities. Six soft-bottom benthic assemblages and two sea grass biotopes (Cymodocea nodosa and Posidonia oceanica were revealed by means of underwater images and multivariate analysis (TWINSPAN on samples collected. The communities inhabiting the infralittoral sandy and coarse sediments corresponded to those previously described in the Mediterranean Sea, whereas a large complex transition between sandy and muddy communities was recognized on circalittoral soft-bottoms. Information obtained with this approach was used to draw a map of the investigated areas at 1:10,000 scale. The employment of the two techniques was cost effective for both time and research effort.

  7. Special mean motion resonance pairs: Mimas-Tethys and Titan-Hyperion

    CERN Document Server

    Luan, Jing

    2014-01-01

    Five pairs of large solar system satellites occupy first order mean-motion resonances (MMRs). Among these, the pairs of Mimas-Tethys and Titan-Hyperion are special. They are located much deeper in resonance than the others and their critical arguments librate with much greater amplitudes. These characteristics are traced to the insignificant damping, over $\\Gyr$ timescales, of Mimas's orbital inclination and Hyperion's orbital eccentricity. Absent that, these resonances would not survive. Instead their librations would be overstable and escape from resonance would occur on the relevant damping time. Unlike the aforementioned MMRs, those involving Enceladus-Dione, Io-Europa, and Europa-Ganymede are limited by eccentricity damping. They must either remain at the shallow depths they currently occupy, or, if they venture deeper, retreat after a limited time. The latter seems almost certain for Enceladus-Dione and quite likely for the others, We examine the MMRs involving Mimas-Tethys and Titan-Hyperion under the ...

  8. Impact crater relaxation on Dione and Tethys and relation to past heat flow

    Science.gov (United States)

    White, Oliver L.; Schenk, Paul M.; Bellagamba, Anthony W.; Grimm, Ashley M.; Dombard, Andrew J.; Bray, Veronica J.

    2017-05-01

    Relating relaxation of impact crater topography to past heat flow through the crusts of icy satellites is a technique that has been applied to satellites around Jupiter and Saturn. We use global digital elevation models of the surfaces of Dione and Tethys generated from Cassini data to obtain crater depth/diameter (d/D) data. Relaxation is found to affect craters down to smaller diameters on these satellites compared to Rhea. We perform relaxation simulations in order to assess the heat flow necessary to relax craters on Dione and Tethys to their present morphologies. Heat flows exceeding 60 mW m-2 are required to relax several craters on both satellites, and relaxation appears to be subject to geographical controls. On Dione, we define a 'relaxation dichotomy' that separates the more relaxed craters in sparsely cratered plains from the less relaxed craters in heavily cratered terrain. The configuration of this dichotomy resembles that of the structural-geological dichotomy on Enceladus, implying that a similar resonance-induced tidal heating mechanism concentrated in the southern hemisphere may have affected both satellites. Defining geographical distribution of relaxation on Tethys is hindered by the presence of the young Odysseus impact and its associated ejecta.

  9. Zooplankton communities fluctuations from 1995 to 2005 in the Bay of Villefranche-sur-Mer (Northern Ligurian Sea, France)

    Science.gov (United States)

    Vandromme, P.; Stemmann, L.; Berline, L.; Gasparini, S.; Mousseau, L.; Prejger, F.; Passafiume, O.; Guarini, J.-M.; Gorsky, G.

    2010-12-01

    An integrated analysis of the pelagic ecosystems of the Ligurian Sea is performed combining time series of different zooplankton groups (small and large copepods, chaetognaths, appendicularians, pteropods, thaliaceans, decapods larvae, other crustaceans, other gelatinous and other zooplankton), chlorophyll-a and nutrients, seawater salinity, temperature and density and local weather at the Point B coastal station (Northern Ligurian Sea). From January 1995 to December 2005, a shift in most variables occurred ca. 2000. From 1995 to 2000 winters were wet and mild resulting in lower winter sea surface density. These years showed lower than average nutrients and zooplankton concentrations while phytoplankton biomass was higher. After 2000, winters were colder and dryer resulting in higher sea surface density. Nutrients and zooplankton showed higher concentrations while phytoplankton was lower than average. The ca. 2000 shift was observed for most zooplankton groups with a one year delay for certain groups. The observed patterns suggest that the pelagic ecosystem trophic state is mostly set by the winter forcing on the convection that upwells nutrients to the surface sustaining the spring bloom. However, low phytoplankton concentrations in higher nitrate and zooplankton conditions during the well mixed years suggest that phytoplankton is controlled by grazers. The proposed mechanisms of convection regimes hold for most of the time series, but specific years with contradicting patterns needed to be explained by other factors. The limitation of phytoplankton growth by the light availability in spring/summer was then proposed as a secondary driving force that can moderate or even reverse the winter forcing. Finally, the eleven years of observation did not reveal a clear link with the North Atlantic Oscillation, suggesting a more complex dynamics linking large scale climate to Ligurian Sea ecosystems or that the length of the plankton monitoring is not yet sufficient to

  10. Long-term decline of radiocesium concentration in seafood from the Ligurian Sea (Northern Italy) after Chernobyl

    Energy Technology Data Exchange (ETDEWEB)

    Gallelli, Giovanni; Panatto, Donatella; Perdelli, Fernanda [Istituto di Igiene e Medicina Preventiva, Universitadi Genova, Genova (Italy); Pellegrino, Claudio [Istituto Zooprofilattico Sperimentale del Piemonte Liguria, Val d`Aosta (Italy)

    1997-02-28

    The activity of {sup 137}Cs, {sup 134}Cs and {sup 40}K in tissues from fish, mollusc and shellfish of the Ligurian sea was measured during 1987-1988. The mean annual concentrations in 1987 were 5.92{+-}4.1 Bq/kg (wet tissue) for {sup 137}Cs and 2.7{+-}1.5 Bq/kg for {sup 134}Cs and 2.46{+-}1.82 and 0.33{+-}0.57 Bq/kg respectively in 1988. The mean value of {sup 40}K activity was 138.6{+-}22.1 Bq/kg. Contamination was significantly higher in the littoral area up to 1000m from the coast (8.39{+-}7.6 and 1.74{+-}2.08 Bq/kg respectively versus 2.91{+-}1.87 and 0.58{+-}0.59 Bq/kg respectively in the open sea). The common octopus (Octopus vulgaris) had the highest radioactivity values and could be utilized as an indicator of radioactivity pollution. There were no significant differences regarding the trophic level, the seafood phylum, or the east and west Ligurian sea areas. Long-term reduction in the sea habitat was estimated at about 200 days for {sup 137}Cs and 110 days for {sup 134}Cs, reflecting differences in the physical half-life of these radionuclides. These values were lower than those found in terrestrial foodstuff and could have reflected dilution of the contaminants in the open sea. The effective dose equivalent for the Ligurian population of radiocesium originating from seafood was estimated at 1.3 {mu}Sv in 1987 and 0.5 {mu}Sv in 1988. These values represent 0.8 and 0.3% respectively of the annual dose (180 {mu}Sv/year) due to {sup 40}K intake with the diet.

  11. Mass transport deposits as witness of Holocene seismic activity on the Ligurian margin, Western Mediterranean (ASTARTE project)

    Science.gov (United States)

    Samalens, Kevin; Cattaneo, Antonio; Migeon, Sébastien

    2016-04-01

    The Ligurian Margin (Western Mediterranean) is at the transition between the Southern Alpes and the Liguro-Provençal margin and it is one of the most seismic areas of France. Several historic earthquakes have been indexed; the strongest, on February 23rd, 1887, occurred offshore Menton and Imperia and also caused a tsunami wave. Its equivalent magnitude has been estimated between 6 and 6.5. In addition, a moderate recurrent seismicity shakes the margin. The aim of this study is to understand the link between seismic activity and slope destabilization, and to identify the sedimentary deposits resulting from mass transport or turbidity currents. During Malisar (Geoazur laboratory), Prisme 2 and Prisme 3 (Ifremer) cruises, bathymetry, seafloor imagery (SAR), geophysics data (CHIRP SYSIF and high resolution seismics), and sediment cores have been acquired on the continental slope, focussing on canyons and submarine landslides, and in the basin. These data record numerous mass transport deposits (slump, debrites) in the different physiographic areas of the margin. To search for evidences of past Ligurian margin seismicity during the Holocene, we focused on the northeast part of the margin, the Finale area. We identified and sampled acoustically transparent Mass Transport Deposits up to 20-m thick in the bottom of three coaleshing canyons: Noli, Pora and Centa canyons from W to E in the area offshore Finale Ligure. We also recovered an MTD in the collecting deeper canyon system. MTDs in cores appear as sediment with different degrees of deformation (tilted blocks, slump, debrites) and are topped by hemipelagites. The radiocarbon age of the top of MTDs can be considered synchronous and centered around 4900 yr BP. Mass wasting occurring over more than 50 km of the Ligurian margin could indicate that an earthquake stroke the Finale area sector at that time.

  12. Zooplankton communities fluctuations from 1995 to 2005 in the Bay of Villefranche-sur-Mer (Northern Ligurian Sea, France

    Directory of Open Access Journals (Sweden)

    P. Vandromme

    2010-12-01

    Full Text Available An integrated analysis of the pelagic ecosystems of the Ligurian Sea is performed combining time series of different zooplankton groups (small and large copepods, chaetognaths, appendicularians, pteropods, thaliaceans, decapods larvae, other crustaceans, other gelatinous and other zooplankton, chlorophyll-a and nutrients, seawater salinity, temperature and density and local weather at the Point B coastal station (Northern Ligurian Sea. From January 1995 to December 2005, a shift in most variables occurred ca. 2000. From 1995 to 2000 winters were wet and mild resulting in lower winter sea surface density. These years showed lower than average nutrients and zooplankton concentrations while phytoplankton biomass was higher. After 2000, winters were colder and dryer resulting in higher sea surface density. Nutrients and zooplankton showed higher concentrations while phytoplankton was lower than average. The ca. 2000 shift was observed for most zooplankton groups with a one year delay for certain groups. The observed patterns suggest that the pelagic ecosystem trophic state is mostly set by the winter forcing on the convection that upwells nutrients to the surface sustaining the spring bloom. However, low phytoplankton concentrations in higher nitrate and zooplankton conditions during the well mixed years suggest that phytoplankton is controlled by grazers. The proposed mechanisms of convection regimes hold for most of the time series, but specific years with contradicting patterns needed to be explained by other factors. The limitation of phytoplankton growth by the light availability in spring/summer was then proposed as a secondary driving force that can moderate or even reverse the winter forcing. Finally, the eleven years of observation did not reveal a clear link with the North Atlantic Oscillation, suggesting a more complex dynamics linking large scale climate to Ligurian Sea ecosystems or that the length of the plankton monitoring is

  13. The Jurassic of Denmark and Greenland: The Jurassic of Skåne, southern Sweden

    Directory of Open Access Journals (Sweden)

    Sivhed, Ulf

    2003-10-01

    Full Text Available In Sweden, Jurassic strata are restricted to Skåne and adjacent offshore areas. Jurassic sedimentary rocks predominantly comprise sandy to muddy siliciclastics, with subordinate coal beds andfew carbonate-rich beds. During Mesozoic times, block-faulting took place in the Sorgenfrei–Tornquist Zone, a tectonic zone which transects Skåne in a NW–SE direction. The Jurassic depositionalenvironments in Skåne were thus strongly influenced by uplift and downfaulting, and to some extent by volcanism. Consequently, the sedimentary record reveals evidence of numerous transgressions, regressions and breaks in sedimentation. Relative sea-level changes played a significant role in controlling the facies distribution, as deposition mainly took place in coastal plain to shallow shelf environments.The alluvial deposits in Skåne include floodplain palaeosols, autochthonous coals, overbank sandstones, and stream channel pebbly sandstones. Restricted marine strata comprise intertidalheteroliths with mixed freshwater and marine trace fossil assemblages, and intertidal delta distributary channel sandstones. Shallow marine sediments encompass subtidal and shoreface sandstoneswith herringbone structures, and bioturbated mudstones with tempestite sandstones. Offshore deposits typically comprise extensively bioturbated muddy sandstones.Floral remains, palaeopedology, clay mineralogy and arenite maturity indicate a warm and humid climate in Skåne throughout the Jurassic, possibly with slightly increasing aridity towards the end of the period. Most Jurassic strata in Skåne have been subjected to mild burial diagenesis, and the petroleum generative window has rarely been reached.

  14. The role of East-Tethys seaway closure in the middle Miocene climatic transition (ca. 14 Ma

    Directory of Open Access Journals (Sweden)

    N. Hamon

    2013-04-01

    Full Text Available The middle Miocene climatic transition (MMCT, approximately 14 Ma is a key period in Cenozoic cooling and cryospheric expansion. Despite it is well documented in isotopic record, the causes of the MMCT are still a matter of debate. Among various hypotheses, some authors suggested that it was linked with the final closure of the East-Tethys seaway and subsequent oceanic circulation reorganisation. The aim of the present study is to quantify the impact of varying East-Tethys seaway depths on middle Miocene ocean and climate, in order to better understand its role in the MMCT. We present four sensitivity experiments with a fully coupled ocean-atmosphere generalized circulation model. Our results indicate the presence of a warm and salty water source in the northern Indian Ocean when the East-Tethys is deep-open (4000 or 1000 m, which corresponds to the Tethyan Indian Saline Water (TISW described on the basis of isotopic studies. This water source is absent in the experiments with shallow (250 m and closed East-Tethys, inducing strong changes in the latitudinal density gradient and ultimately the reinforcement of the Antarctic Circumpolar Current (ACC. Moreover, when the East-Tethys seaway is shallow or closed, there is a westward water flow in the Gibraltar Strait that strengthens the Atlantic meridional overturning circulation (AMOC compared to the experiments with deep-open East-Tethys. Our results therefore suggest that the shoaling and final closure of the East-Tethys seaway played a major role in the oceanic circulation reorganisation during the middle Miocene. The results presented here provide new constraints on the timing of the East-Tethys seaway closure, and particularly indicate that, prior to 14 Ma, a deep-open East-Tethys should have allow the formation of TISW. Moreover, whereas the final closure of this seaway likely played a major role in the MMCT, we suggest that it was not the only driver of the global cooling and Antarctica ice

  15. Assimilation of HF radar data in a regional model of the Ligurian Sea

    Science.gov (United States)

    Vandenbulcke, Luc; Barth, Alexander; Beckers, Jean-Marie

    2015-04-01

    An ensemble of ROMS models with 1/60 degree resolution, covering the Ligurian Sea, and nested in the Mediterranean Forecasting System, is coupled with two WERA high-frequency radars run by the NATO Undersea Research Center (now CMRE). The following perturbations are applied to the members of the ensemble: the wind forcing field, the open sea boundary conditions, and a supplementary term in the momentum equation. An ensemble Kalman (EnKF) filter is then used to assimilate hourly-averaged radial currents into the model. A observation operator extracts the corresponding model radial currents from the model currents, then smooths them in the azimuthal direction as a function of distance to the radar. The observations are spatially dense, and not uncorrelated to one another, which is approximated in our experiment by increasing the observation error variance. Different cases are run, with the estimation vector containing the model state (in which case it is called the state vector) or multiple model states at different time steps. In the latter case, the filter is closely related to the Ensemble Smoother and the Asynchronous EnKF. The impact of different parameters is studied: the correlation length of the localization function, the (experimentally determined) total observational error, the stochastic perturbation in the momentum equation, the assimilation window length, etc. The update vector generated by the data assimilation scheme is analyzed to examine whether inertial oscillations are present and corrected. The model surface temperature is also compared with satellite images in order to assess the impact of assimilating one variable (surface currents) on another one (surface temperature).

  16. Sexual behaviour in Ligurian (Northern Italy) adolescents and young people: suggestions for HPV vaccination policies.

    Science.gov (United States)

    Panatto, Donatella; Amicizia, Daniela; Lugarini, Jessica; Sasso, Tiziana; Sormani, Maria Pia; Badolati, Giuseppe; Gasparini, Roberto

    2009-05-29

    Human papillomavirus is a common sexually transmitted virus, and persistent infection with high-risk types is the necessary factor for cervical cancer. We investigated sexual behaviour and the age of the first sexual intercourse among young people (14-24 years) in Liguria (Northern Italy) in order to provide information that might orient the country's future vaccination policy. The Italian Authorities offer free vaccination to 12-year-old females, however a better prevention of HPV would to be implemented by introducing the vaccine to new cohorts of females after the first year of the vaccination campaign. Our survey was carried out from 1st May 2006 to 31st December 2007 and involved 3474 volunteers. We administered a written questionnaire to students (14-24 years) and workers (20-24 years). The median age+/-MAD of the sexual debut was 15+/-1 for both females and males in students group and 16+/-1 for both males and females in workers group. This study provides evidence that many Ligurian adolescents have their first sexual experience at a very early age, and often without protection against sexually transmitted diseases. Furthermore, a large percentage of all age-groups are sexually active and have multiple partners. The aim of this study was to identify those cohorts of females to whom vaccination should be offered free of charge. To this end, we calculated the percentage of infections that could be avoided by vaccination in each age-class: the younger the subjects, the higher the number of preventable infections. Our findings suggest that current HPV vaccination should be implemented by introducing new cohorts, especially young girls (14-16 years).

  17. The Jurassic of Denmark and Greenland: The Upper Jurassic of Europe: its subdivision and correlation

    Directory of Open Access Journals (Sweden)

    Zeiss, Arnold

    2003-10-01

    Full Text Available In the last 40 years, the stratigraphy of the Upper Jurassic of Europe has received much attention and considerable revision; much of the impetus behind this endeavour has stemmed from the work of the International Subcommission on Jurassic Stratigraphy. The Upper Jurassic Series consists of three stages, the Oxfordian, Kimmeridgian and Tithonian which are further subdivided into substages, zones and subzones, primarily on the basis of ammonites. Regional variations between the Mediterranean, Submediterranean and Subboreal provinces are discussed and correlation possibilities indicated. The durations of the Oxfordian, Kimmeridgian and Tithonian Stages are reported to have been 5.3, 3.4 and 6.5 Ma, respectively. This review of the present status of Upper Jurassic stratigraphy aids identification of a number of problems of subdivision and definition of Upper Jurassic stages; in particular these include correlation of the base of the Kimmeridgian and the top of the Tithonian between Submediterranean and Subboreal Europe. Although still primarily based on ammonite stratigraphy, subdivision of the Upper Jurassic is increasingly being refined by the incorporation of other fossil groups; these include both megafossils, such as aptychi, belemnites, bivalves, gastropods, brachiopods, echinoderms, corals, sponges and vertebrates, and microfossils such as foraminifera, radiolaria, ciliata, ostracodes, dinoflagellates, calcareous nannofossils, charophyaceae, dasycladaceae, spores and pollen. Important future developments will depend on the detailed integration of these disparate biostratigraphic data and their precise combination with the abundant new data from sequence stratigraphy, utilising the high degree of stratigraphic resolution offered by certain groups of fossils. This article also contains some notes on the recent results of magnetostratigraphy and sequence chronostratigraphy.

  18. Water Place Names in the Pre-Latin Ligurian Context. A Study in Prehistoric Toponomastics and Semantics

    Directory of Open Access Journals (Sweden)

    Francesco Perono Cacciafoco

    2013-11-01

    Full Text Available This paper outlines a new applied epistemological aspect of the so-called Convergence Theory that is aimed to develop a potentially “homogeneous” vision between the different approaches in the field of Indo-European linguistics. This work tries to reconstruct an Italian and European toponymic area characterized by place names linked to the root *alb-, with a delineation of the “semantic steps” produced, over the centuries, by the same root, following a potential all-embracing approach. It seems that paleo-Ligurian place names of the type Alba, Old European river names Albis and the like, as well as their ablauting forms Olb- (> Orb- in Romance Ligurian, do not directly reflect the proto-Indo-European adjective *albho- 'white'; but rather they all seem to continue a pre-proto-Indo-European extended root *Hal-bh- 'water', cognate with the Sumerian Halbia (> Akkadian Halpium 'spring', 'well', 'water mass', 'water hole'. A further analysis of this *Hal-bh-, moreover, leads to a comparison with the proto-Indo-European root *Hal- 'nourish'. The proto-Indo-European suffixed form *HwaH-r- 'water', then, demonstrates a similar diffusion.

  19. Application of a SEEK filter to a 1D biogeochemical model of the Ligurian Sea: Twin experiments and real data assimilation

    NARCIS (Netherlands)

    Raick, C.; Alvera-Azcarate, A.; Barth, A.; Brankart, J.-M.; Soetaert, K.E.R.; Grégoire, M.

    2007-01-01

    The Singular Evolutive Extended Kalman (SEEK) filter has been implemented to assimilate in-situ data in a 1D coupled physical-ecosystem model of the Ligurian Sea. The biogeochemical model describes the partly decoupled nitrogen and carbon cycles of the pelagic food web. The GHER hydrodynamic model (

  20. Ecological response of benthic foraminifera to the acid drainage from mine areas. An example from the Gromolo torrent mouth (Eastern Ligurian Sea, Italy)

    Science.gov (United States)

    Bergamin, Luisa; Capello, Marco; Carbone, Cristina; Magno, Maria Celia; Consani, Sirio; Cutroneo, Laura; Ferraro, Luciana; Pierfranceschi, Giancarlo; Romano, Elena

    2016-04-01

    Benthic foraminiferal assemblages react in short time to natural and anthropogenic environmental changes and, for this, they are considered as reliable indicators of environmental quality. An interesting application of these indicators is the study of their response to environmental changes in coastal marine areas, affected by dismissed mines and dump areas. The Libiola Fe-Cu sulphide mine was intensively exploited in 19th and 20th centuries, and the activity ended in 1962. The sulphide mineral assemblages consist of pyrite and chalcopyrite, with minor sphalerite and pyrrhotite, in a gangue of quartz and chlorite. The sulphide ore occurs within the Jurassic ophiolites of the Northern Apennines which were subjected to metamorphic and tectonic processes during the subsequent Apennine orogenesis. Waters circulating in the Libiola mine area, and discharging in the adjacent streams and creeks, are strongly polluted due to the diffuse occurrence of Acid Mine Drainage processes. The Gromolo torrent collects these acidic waters enriched of heavy metals which flow into Ligurian Sea. The study area is characterised by a shelf with a gentle slope, mainly constituted by sediment supplied by Entella torrent. The general circulation has trend from East to West and the coastal drift is generally eastwards. A total of 15 marine sediment samples (upper 2 cm) were collected by means of Van Veen grab in the coastal zone close to the Gromolo mouth and analyzed for living (rose Bengal stained) and dead benthic foraminifera, together with grain size, metals and trace elements, and metal fractioning. Quantitative foraminiferal parameters, like as abundance, species diversity, heterogeneity and assemblage composition, were determined and evaluated for environmental purpose. Additionally, possible increase above the natural background level of deformed specimens was considered as indicative of metal contamination. The grain-size analyses highlighted mainly sandy sediments, characterized by

  1. Tethys: A Platform for Water Resources Modeling and Decision Support Apps

    Science.gov (United States)

    Nelson, J.; Swain, N. R.

    2015-12-01

    The interactive nature of web applications or "web apps" makes it an excellent medium for conveying complex scientific concepts to lay audiences and creating decision support tools that harness cutting edge modeling techniques. However, the technical expertise required to develop web apps represents a barrier for would-be developers. This barrier can be characterized by the following hurdles that developers must overcome: (1) identify, select, and install software that meet the spatial and computational capabilities commonly required for water resources modeling; (2) orchestrate the use of multiple free and open source (FOSS) projects and navigate their differing application programming interfaces; (3) learn the multi-language programming skills required for modern web development; and (4) develop a web-secure and fully featured web portal to host the app. Tethys Platform has been developed to lower the technical barrier and minimize the initial development investment that prohibits many scientists and engineers from making use of the web app medium. It includes (1) a suite of FOSS that address the unique data and computational needs common to water resources web app development, (2) a Python software development kit that streamlines development, and (3) a customizable web portal that is used to deploy the completed web apps. Tethys synthesizes several software projects including PostGIS, 52°North WPS, GeoServer, Google Maps™, OpenLayers, and Highcharts. It has been used to develop a broad array of web apps for water resources modeling and decision support for several projects including CI-WATER, HydroShare, and the National Flood Interoperability Experiment. The presentation will include live demos of some of the apps that have been developed using Tethys to demonstrate its capabilities.

  2. TethysCluster: A comprehensive approach for harnessing cloud resources for hydrologic modeling

    Science.gov (United States)

    Nelson, J.; Jones, N.; Ames, D. P.

    2015-12-01

    Advances in water resources modeling are improving the information that can be supplied to support decisions affecting the safety and sustainability of society. However, as water resources models become more sophisticated and data-intensive they require more computational power to run. Purchasing and maintaining the computing facilities needed to support certain modeling tasks has been cost-prohibitive for many organizations. With the advent of the cloud, the computing resources needed to address this challenge are now available and cost-effective, yet there still remains a significant technical barrier to leverage these resources. This barrier inhibits many decision makers and even trained engineers from taking advantage of the best science and tools available. Here we present the Python tools TethysCluster and CondorPy, that have been developed to lower the barrier to model computation in the cloud by providing (1) programmatic access to dynamically scalable computing resources, (2) a batch scheduling system to queue and dispatch the jobs to the computing resources, (3) data management for job inputs and outputs, and (4) the ability to dynamically create, submit, and monitor computing jobs. These Python tools leverage the open source, computing-resource management, and job management software, HTCondor, to offer a flexible and scalable distributed-computing environment. While TethysCluster and CondorPy can be used independently to provision computing resources and perform large modeling tasks, they have also been integrated into Tethys Platform, a development platform for water resources web apps, to enable computing support for modeling workflows and decision-support systems deployed as web apps.

  3. Short term summer to autumn variability of dissolved lipid classes in the Ligurian sea (NW Mediterranean

    Directory of Open Access Journals (Sweden)

    M. Duflos

    2009-07-01

    Full Text Available Changes in concentration and composition of Iatroscan-measured dissolved lipids were examined at a daily to month scale, in relation to the hydrological and biological context at a central site of the Ligurian sea, NW Mediterranean during the PECHE-DYNAPROC 2 experiment (14 September to 17 October 2004. Lipid concentrations (excluding hydrocarbons (TLd-HC and TLd-HC to DOC ratios in the 0–1000 m water column, varied from 5.3 to 48.5 μg l−1 and 0.01 to 0.09, respectively. The highest TLd-HC concentration values were found in the 0–50 m surface layer, coinciding with phytoplankton biomass. Significant correlations (p<0.01, n=87 between glycolipids from chloroplast membranes, namely the monogalactosyldiacylglycerols, a major component of dissolved lipids (25.1±10.8% of TLd-HC, n=166, and various phytoplankton pigments (chlorophyll cs-170, violaxanthin, diadinoxanthin, zeaxanthin, and lutein, suggested that picoeucaryote phytoplankton were a major source of dissolved lipids. Lipid metabolites (free fatty acids, alcohols, diacylglycerols and monoacylglycerols, an other important component of TLd-HC (37.6±11.1%, n=166, showed a greater degree of degradation of lipids in this transitional period than previously observed earlier in the year. Zooplankton wax and steryl ester biomarkers (WSE and triacylglycerols showed a distinct periodicity in the mesopelagic layer throughout the period investigated. Concentrations of WSE (5.5–13.6 μg/l increased in the 0–150 m surface layer, mid-way through the cruise (4–6 October, before the winter mixing. WSE were observed later and deeper in the mesopelagic layer (6–11 October, accompanied by rebounds in hydrocarbons (6–8 October and phospholipid concentrations (12 October in the 400–1000 m depth layer. Zooplankton migration and/or fecal pellet egestion, followed by DOM release from POM, were likely responsible for the appearance of these lipid signatures

  4. Tethys: A Platform for Water Resources Modeling and Decision Support Apps

    Science.gov (United States)

    Swain, N. R.; Christensen, S. D.; Jones, N.; Nelson, E. J.

    2014-12-01

    Cloud-based applications or apps are a promising medium through which water resources models and data can be conveyed in a user-friendly environment—making them more accessible to decision-makers and stakeholders. In the context of this work, a water resources web app is a web application that exposes limited modeling functionality for a scenario exploration activity in a structured workflow (e.g.: land use change runoff analysis, snowmelt runoff prediction, and flood potential analysis). The technical expertise required to develop water resources web apps can be a barrier to many potential developers of water resources apps. One challenge that developers face is in providing spatial storage, analysis, and visualization for the spatial data that is inherent to water resources models. The software projects that provide this functionality are non-standard to web development and there are a large number of free and open source software (FOSS) projects to choose from. In addition, it is often required to synthesize several software projects to provide all of the needed functionality. Another challenge for the developer will be orchestrating the use of several software components. Consequently, the initial software development investment required to deploy an effective water resources cloud-based application can be substantial. The Tethys Platform has been developed to lower the technical barrier and minimize the initial development investment that prohibits many scientists and engineers from making use of the web app medium. Tethys synthesizes several software projects including PostGIS for spatial storage, 52°North WPS for spatial analysis, GeoServer for spatial publishing, Google Earth™, Google Maps™ and OpenLayers for spatial visualization, and Highcharts for plotting tabular data. The software selection came after a literature review of software projects being used to create existing earth sciences web apps. All of the software is linked via a Python

  5. Heterogeneous oxygenation states in the Atlantic and Tethys oceans during Oceanic Anoxic Event 2

    Science.gov (United States)

    Westermann, Stéphane; Vance, Derek; Cameron, Vyllinniskii; Archer, Corey; Robinson, Stuart A.

    2014-10-01

    The Cenomanian-Turonian boundary (ca. 93.5 Ma) is marked by an episode of profound environmental change, including a major perturbation of the carbon cycle and an Oceanic Anoxic Event (OAE-2). Here, we present molybdenum (Mo) isotope variations within the OAE-2 interval for four sections from the western Tethys (Furlo and La Contessa) and the North-Atlantic (ODP site 1276 and DSDP site 367). The main target of this study is to investigate the extent of reducing conditions (truly global in extent or restricted to poorly-ventilated restricted deep basins), with particular reference to the relationship between the change in the oxygenation state of the ocean and the link to global perturbations of the carbon cycle recorded in carbon isotopes. All four sections show fluctuations in the redox sensitive trace metal (RSTE) distribution, suggesting rapid variations in local redox conditions, ranging from anoxic to euxinic. The RSTE enrichment factors (EFs) also suggest different depositional conditions and paleoceanographic processes in the western Tethys versus the North Atlantic. Whereas the North Atlantic sites show evidence of weak watermass restriction associated with the action of a particulate shuttle within the water column, the EFs of the Tethyan sections are characteristic of unrestricted marine systems. Mo isotopes show surprisingly negative values through the Tethyan sections. At the onset of OAE-2, an increasing trend in δMo98 is observed, with values ranging from -0.6 to 0.6‰. During the second half of OAE-2, the δMo98 curve shows a progressive shift towards more negative values. In the North Atlantic, δMo98 signatures from ODP site 1276 show a similar behaviour as observed in the western Tethys. At DSDP site 367, Mo isotopes are generally heavier during OAE-2, fluctuating around an average value of 1.1‰. This is consistent with fully euxinic conditions and the black shales deposited may have recorded the seawater signature during OAE-2. The Mo isotope

  6. Palaeotectonic and palaeogeographic evolution of the western Tethys and PeriTethyan domain (IGCP Project 369)

    Institute of Scientific and Technical Information of China (English)

    G. M. Stampfli; G. D. Borel; W. Cavazza; J. Mosar; P. A. Ziegler

    2001-01-01

    @@ Project No. 369 ("Comparative Evolution of PeriTethyan Rift Basins") of the International Geological Correla tion Program produced a new palaeotectonic-palaeo geographic atlas of the western PeriTethyan domain. The atlas contains more than two hundred new maps and documents grouped in nine regional sets (Iberia,Polish Trough, Eastern European and Scythian Platforms, Moesian Platform, Levant, Arabian Platform,Northern Africa, NE Africa-NW Arabia, Libya-Pelagian Shelf) plus a set of reconstructions for the whole western Tethys.

  7. Redox changes across the Triassic-Jurassic boundary: From anoxic to euxinic black shale deposition

    Science.gov (United States)

    Richoz, Sylvain; van de Schootbrugge, Bas; Püttmann, Wilhelm; Heunisch, Carmen; Quan, Tracy M.; Lindström, Sofie; Fiebig, Jens; Pross, Joerg

    2010-05-01

    consistent with the long-term effects of CO2 release, greenhouse warming and post-extinction productivity breakdown. Isorenieratane occurs repeatedly in Hettangian and Sinemurian organic rich sediments. Hence, repeated PZE in epicontinental seas bordering the Tethys Ocean may have contributed to the slow recovery of shallow marine ecosystems after the Triassic-Jurassic boundary.

  8. Mesozoic-Cenozoic mafic magmatism in Sanandaj-Sirjan Zone, Zagros Orogen (Western Iran): Geochemical and isotopic inferences from Middle Jurassic and Late Eocene gabbros

    Science.gov (United States)

    Deevsalar, R.; Shinjo, R.; Ghaderi, M.; Murata, M.; Hoskin, P. W. O.; Oshiro, S.; Wang, K. L.; Lee, H. Y.; Neill, I.

    2017-07-01

    One of the consequences of Neo-Tethys ocean subduction beneath the Central Iranian Micro-continent (CIMC) is the development of rare gabbroic intrusions in the Malayer-Boroujerd Plutonic Complex (MBPC) located in the Sanandaj-Sirjan Zone (SaSZ) of the Zagros Orogenic belt. The MBPC is a suite of extensive felsic and lesser mafic magmatic products in the northern SaSZ with geochemical signatures of arc-like magmatism during the Middle Jurassic (Ghorveh-Aligudarz arc) and intraplate type in the Late Eocene. Middle Jurassic gabbros (non-cumulate and cumulate) have low-Ti concentrations (non-cumulates belong to common liquid line of descent, with complementary trace element patterns. Much of the variation between samples can be modeled by fractional crystallization (FC) of a common parent; only one cumulate gabbro from this suite exhibits isotopic evidence of contamination, probably by Rb-depleted crustal materials. The Late Eocene gabbros have relatively high-Ti (> 1 wt.%) and display isotopically depleted Sr-Nd values (initial 87Sr/86Sr: 0.7044-0.7087, εNd(t): 1.9 -+3.2, barring one crustally-contaminated sample). OIB-like trace element characteristics such as enriched HFSE, and only minor enrichment of LILE and LREE, reflect a within-plate character and asthenospheric source. Trace element modeling indicates small degree melting (fmelting: 0.05) of upper mantle lherzolite (garnet:spinel 3:1) followed by higher degree melting (fmelting: 0.15) at shallower depths (garnet:spinel 4.5:2). The Eocene parental magma underwent FC of olivine and clinopyroxene. We propose that Eocene asthenospheric upwelling was triggered by slab tearing in response to slab-rollback, which is elsewhere reported to have triggered a 'flare-up' of extension-related magmatism across Iran. Three stages of tectono-magmatic evolution in the Ghorveh-Aligudarz arc segment of the N-SaSZ are represented by: 1) arc-like magmatism during active subduction of the Neo-Tethys seaway at Middle Jurassic, 2

  9. Characteristics of rare earth elements and cerium anomalies in cherts from the Paleo-Tethys in Changning-Menglian belt in western Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    丁林; 钟大赉

    1996-01-01

    Based on research on rare earth elements (REEs) and cerium anomalies in cherts from the Paleo-Tethys, their depositional environments are shown and the evolution of the Paleo-Tethys is traced. The amount of terrigenous, biogenic and hydrothermal inputs are the important factors that affect the REEs composition of the cherts.

  10. Low durophagous predation on Toarcian (Early Jurassic ammonoids in the northwestern Panthalassa shelf basin

    Directory of Open Access Journals (Sweden)

    Yusuke Takeda

    2015-12-01

    Full Text Available Predatory shell breakage is known to occur occasionally on the ventrolateral portion of the body chamber in Mesozoic ammonoids. Here we report, for the first time, quantitative data of shell breakage in large ammonoid samples that were recovered from the lower Toarcian (Lower Jurassic strata in the Toyora area, western Japan. The strata yielding the ammonoid samples consisted mostly of well-laminated, bituminous black shale that was deposited in an oxygen-depleted shelf basin of the northwestern Panthalassa, under the influence of the early Toarcian oceanic anoxic event. Among a total of 1305 specimens from 18 localities, apparent shell breakage was recognised in 35 specimens belonging to 7 genera, resulting in only a 2.7% frequency of occurrence relative to the total number of specimens. The breakage occurs mostly on the ventrolateral side of the body chamber with a complete shell aperture. This fact, as well as the low energy bottom condition suggested for the ammonoid-bearing shale, indicate that the shell breaks observed in the examined ammonoids were not produced by non-biological, post-mortem biostratinomical processes but were lethal injuries inflicted by nektonic predators such as reptiles, jawed fishes, coleoids, nautiloids, and carnivorous ammonoids with calcified rostral tips in their upper and lower jaws. Similar predatory shell breaks on the ventrolateral side of the body chamber have been found in contemporaneous ammonoid assemblages of the Tethys Realm, with a much higher frequency of occurrence than in the examined samples from the northwestern Panthalassa, suggesting a weaker durophagous predation pressure on ammonoids in the latter bioprovince.

  11. Assymmetric eddy populations in adjacent basins – a high resolution numerical study of the Tyrrhenian and Ligurian Seas

    Directory of Open Access Journals (Sweden)

    E. Casella

    2012-11-01

    Full Text Available A high-resolution ocean circulation modelling system forced with a high-resolution numerical wind product was used to study the mesoscale and sub-mesoscale eddy population of the North-Western Mediterranean Sea, contrasting eddy-activity between the Tyrrhenian and Ligurian sub-basins. Numerical solutions reproduced some of the known regional dynamics, namely the occurrence and oceanic implications of Mistral events, the convective cell leeward of the Gulf of Lion, as well as the Balearic frontal system. Calculated transport across the Corsica Channel followed a similar trend, when compared to the transport computed from a moored current meter. The analysis of the results showed that surface eddy activity is mostly confined to the boundary-currents, whereas in the deeper layers most eddies are concentrated on the central-deeper part of the basins. The Liguro-Provençal basin shows a much higher concentration of intermediate and deep-water eddies, when compared to the Tyrrhenian basin. Sub-mesoscale surface eddies tend to merge and migrate vertically onto intermediate waters. Intense eddy activity in the boundary-current surrounding the Liguro-Provençal Gyre, concentrate high-productivity, manifested by higher concentrations of mean sea surface chlorophyll, in the central part of the gyre, defined herein as the Ligurian Productive Pool (LPP. On average, the Tyrrhenian was mostly oligotrophic except for a small productive vortice in the south-eastern (leeward side of Corsica. The transport in the Tyrrhenian Gyre, and across the basin is one order of magnitude higher than the transport calculated for the Liguro-Provençal basin. A high concentration of eddies in the passage between the Balearic Archipelago and Sardinia suggests retention and longer residence times of nutrient rich water in the "Ligurian pool", compared to a "fast draining" Tyrrhenian basin. Previous studies support the cyclonic gyre circulation generated in the Liguro

  12. Lower Jurassic palynostratigraphy of Eastern Siberia

    Science.gov (United States)

    Goryacheva, A. A.

    2017-05-01

    This paper presents the results of a palynological study of the natural outcrops of the Lower and Middle Jurassic on the Kelimyar River (Outcrops 5, 6, 7, 14, and 16) and two boreholes, Middle-Nakynskaya and Ygyata-Tyungskaya 1, in Eastern Siberia. The Ukugut, Tyung, Motorchuna, Suntar, Kyrin, and Kelimyar formations were studied. Six biostrata with dinocysts were established for the Upper Sinemurian-Toarcian. The analysis of the stratigraphic ranges of dinocysts in the sections allowed the identification of the stratigraphic ranges for important genera of dinocysts, which enabled the updating of the geochronology of some biostrata. Three main stages of the evolution of dinocysts in the Early Jurassic in the Siberian Paleobasin were characterized by the appearance, diversification, and disappearance of some orders of dinocysts at certain times. Seven biostrata (beds with characteristic palynoassemblages) were established for the upper Sinemurian-Toarcian on the basis of the study of the taxonomic composition of spores and pollen of land plants and successive changes in the composition of the palynospectra.

  13. Cassiopidae gastropods, influence of Tethys Sea of the Romualdo Formation (Aptian-Albian), Araripe Basin, Brazil

    Science.gov (United States)

    Pereira, Priscilla Albuquerque; Cassab, Rita de Cassia Tardin; Barreto, Alcina Magnólia Franca

    2016-10-01

    The Cassiopidae family belongs to a group of gastropods of the Tethyan Realm, whose origin and dispersion are related a transgression of the Tethys Sea during the Early Cretaceous. The Romualdo Formation in the Araripe Basin, located in Northeast Brazil, presents fossil assemblages with echinoids, bivalves and cassiopid gastropods, indicating a marine sedimentation at the top of the formation. This research reveals three new species of this fauna: Gymnentome (Craginia) beurleni sp. nov., 'Pseudomesalia' ('Pseudomesalia') mennessieri sp. nov and 'Pseudomesalia' ('Pseudomesalia') santanensis sp. nov. We also review two other species: Craginia araripensisBeurlen, 1964 and Gymnentome romualdoiBeurlen, 1964, which we reclassify taxonomically as Paraglauconia (Diglauconia) araripensis and Gymnentome (Gymnentome) romualdoi, respectively; Paraglauconia (Diglauconia) lyrica Maury, 1936 and Gymnentome (Gymnentome) carregozica Maury, 1936 were the first recorded species in the Araripe Basin. The occurrence of these cassiopid gastropod fauna in other basins, such as Sergipe, Potiguar and Parnaíba, indicate the influence of waters coming from the north through the Tethys Sea in the Aptian-Albian and in the marginal continental basins of the Brazilian Northeast.

  14. Role of Variscan tectonics inheritance in the Jurassic rifting of the passive margin of Adria: insights from the Canavese Zone (Western Southern Alps, Italy)

    Science.gov (United States)

    De Caroli, Sara; Succo, Andrea; Centelli, Arianna; Barbero, Edoardo; Borghi, Alessandro; Balestro, Gianni; Festa, Andrea

    2017-04-01

    The formation of rifted continental margins by extension of continental lithosphere leading to seafloor spreading is a complex component of the plate tectonic cycle. Geological mapping, supported by multidisciplinary analyses of rifted continental margins may thus provide significant information to better understand and model the related processes, and explain the geometry of those margins as observed by means of seismic imaging. We present here our new findings on the Canavese Zone (Italian Western Alps), which is inferred to represent the remnant of the Jurassic syn-rift stretching, thinning and dismemberment of the distal passive margin of Adria, occurred during the opening of the Northern Alpine Tethys. Through multiscale and multidisciplinary, field- and laboratory-based structural, stratigraphic and petrographic studies (from geological map scale to mesoscale and microscope scale), we document that the tectonic dismemberment of the rifted continental margin of Adria did not simply result from the syn-rift Jurassic extension, but was strongly favored by the inheritance of older (Variscan and post-Variscan) tectonic stages, which controlled earlier lithospheric weakness. Our findings show the existence of two different tectonic units of the pre-Variscan basement, which were deformed, juxtaposed and exhumed already during the Variscan orogeny as constraint by (i) intrusion of early Permian granitoids, (ii) emplacement of volcanic rocks and (iii) unconformable overlie of Permian deposits on those metamorphic units. The syn-extensional (syn-rift) Jurassic faults, which affect the Mesozoic sedimentary succession, show only limited vertical displacement that was ineffective in producing and justifying the crustal thinning observed in pre-Variscan basement units. Finally, Late Cretaceous-Early Paleocene and Late Cenozoic strike-slip faulting (i.e. Alpine and Insubric tectonic stages) reactivated previously formed faults, leading to the formation of a complex tectonic

  15. Polygonal Impact Craters on selected Minor Bodies: Rhea, Dione, Tethys, Ceres, and Vesta

    Science.gov (United States)

    Neidhart, Tanja; Leitner, Johannes; Firneis, Maria

    2017-04-01

    A polygonal impact crater (PIC) is a crater that does not have a full circular shape in plane view but consists of straight crater rim segments. PICs are common on all objects in our solar system that show a cratered surface. Previous studies showed that PICs make up about 10-25% of craters on Mercury, Venus, Mars, and the Moon [1, 2, 3, 4]. Although there have been several studies on PICs on the terrestrial planets, and the Moon there are only very few investigations on PICs on minor bodies, even though there exist surface maps of Rhea, Tethys, Dione, Ceres, and Vesta that have an appropriate resolution. The aim of this study is to get more information about the abundance and characteristics of PICs on these objects. We analysed all approved craters on Rhea, Dione, Tethys, Ceres, and Vesta using images provided by the IAU/NASA/USGS Planetary Database [5]. For the classification of PICs the definition by [2] was used which states that a crater is polygonal if it consists of at least two straight crater rim segments having a discernable angle. In total 417 impact craters were examined and 227 of them were classified as polygonal. On Rhea about 48% of the approved craters are PICs, on Dione 59%, on Tethys 34%, on Ceres 74%, and on Vesta 56%. The comparison with studies on PICs on terrestrial planets, and the Moon conducted by [1, 2, 3, 4] showed that the percentage of PICs found in this study is much higher. Most of the PICs have two or three straight rim segments and only few PICs are hexagonal or pentagonal. The mean angle between the straight rims yields 121° for Rhea, 124° for Dione, 123° for Tethys, 133° for Ceres, and 134° for Vesta. These angles are well in accordance to an average angle of 112° on Mercury [1]. Also the size distribution of PICs is in accordance to results by [4] who proved that PICs seem to favor small to middle size diameters. The largest diameters of non-polygonal craters on Vesta range from 0.6 km to 450 km while the diameters of

  16. The Jurassic of Denmark and Greenland: The Jurassic of the Netherlands

    Directory of Open Access Journals (Sweden)

    Herngreen, G.F. Waldemar

    2003-10-01

    Full Text Available A recent revision of the lithostratigraphy of the Netherlands has triggered an extensive re-evaluation of existing ideas on the Jurassic structural and depositional history. Significant advances can be attributed to the incorporation of sequence stratigraphic concepts. In the course of the Triassic and Jurassic, structural complexity increased progressively. The Jurassic sedimentary succession can be subdivided into three depositional megasequences. Megasequence I (Rhaetian- Aalenian reflects the period between the so-called early and mid-Cimmerian tectonic phases. Megasequence II (Aalenian - Middle Callovian covers the period of activity of the mid-Cimmerian phase. Megasequence III (Middle Callovian - Ryazanian corresponds with the period between the mid-Cimmerian and late Cimmerian phases (particularly after pulse II. In this latter megasequence, six stages (IIIa-f are recognised. Sediments deposited during the Rhaetian and Ryazanian bear a stronger affinity with the Jurassic succession than with Triassic and Cretaceous sediments respectively. These stages are thus treated here as an integral part of the Jurassic succession. During the Rhaetian-Bajocian the area subsided relatively uniformly. A sheet of predominantly fine-grained marine sediments of great lateral uniformity was deposited. During the Toarcian, in particular, basin circulation was largely restricted. The cooling that followed the thermal Central North Sea dome uplift triggered an important extensional phase during the Aalenian-Callovian. The rift phase resulted in the formation of several smaller basins, each with its own characteristic depositional succession. The basins fall into three structural provinces: the eastern province (Lower Saxony Basin, E-W-striking; the northern province (Central Graben, N-S-striking; and the southern-central system (Roer Valley Graben - Broad Fourteens, with a strong NW-SE strike. The mid-Cimmerian event started to affect the Dutch basins during

  17. Observed development of the vertical structure of the marine boundary layer during the LASIE experiment in the Ligurian Sea

    DEFF Research Database (Denmark)

    Sempreviva, Anna Maria; Schiano, M.E.; Pensieri, S.

    2010-01-01

    In the marine environment, complete datasets describing the surface layer and the vertical structure of the Marine Atmospheric Boundary Layer (MABL), through its entire depth, are less frequent than over land, due to the high cost of measuring campaigns. During the seven days of the Ligurian Air-Sea...... Interaction Experiment (LASIE), organized by the NATO Undersea Research Centre (NURC) in the Mediterranean Sea, extensive in situ and remote sensing measurements were collected from instruments placed on a spar buoy and a ship. Standard surface meteorological measurements were collected by meteorological...... and dry air from land advected over a colder sea, induced a stably stratified Internal Boundary Layer (IBL) and a consequent change in the structure of the vertical profiles of potential temperature and relative humidity....

  18. Kinematics of Late Cretaceous subduction initiation in the Neo-Tethys Ocean reconstructed from ophiolites of Turkey, Cyprus, and Syria

    NARCIS (Netherlands)

    Maffione, Marco; van Hinsbergen, Douwe J.J.; de Gelder, Giovanni I.N.O.; van der Goes, Freek C.; Morris, Antony

    2017-01-01

    Formation of new subduction zones represents one of the cornerstones of plate tectonics, yet both the kinematics and geodynamics governing this process remain enigmatic. A major subduction initiation event occurred in the Late Cretaceous, within the Neo-Tethys Ocean between Gondwana and Eurasia. Sup

  19. Kinematics of Late Cretaceous subduction initiation in the Neo-Tethys Ocean reconstructed from ophiolites of Turkey, Cyprus, and Syria

    NARCIS (Netherlands)

    Maffione, Marco; van Hinsbergen, Douwe J.J.; de Gelder, Giovanni I.N.O.; van der Goes, Freek C.; Morris, Antony

    Formation of new subduction zones represents one of the cornerstones of plate tectonics, yet both the kinematics and geodynamics governing this process remain enigmatic. A major subduction initiation event occurred in the Late Cretaceous, within the Neo-Tethys Ocean between Gondwana and Eurasia.

  20. Did high Neo-Tethys subduction rates contribute to early Cenozoic warming?

    Directory of Open Access Journals (Sweden)

    G. Hoareau

    2015-07-01

    Full Text Available The 58–51 Ma interval was characterized by a long-term increase of global temperatures (+4 to +6 °C up to the Early Eocene Climate Optimum (EECO, 52.9–50.7 Ma, the warmest interval of the Cenozoic. It was recently suggested that sustained high atmospheric pCO2, controlling warm early Cenozoic climate, may have been released during Neo-Tethys closure through the subduction of large amounts of pelagic carbonates and their recycling as CO2 at arc volcanoes ("carbonate subduction factory". To analyze the impact of Neo-Tethys closure on early Cenozoic warming, we have modeled the volume of subducted sediments and the amount of CO2 emitted at active arc volcanoes along the northern Tethys margin. The impact of calculated CO2 fluxes on global temperature during the early Cenozoic have then been tested using a climate carbon cycle model (GEOCLIM. We first show that CO2 production may have reached up to 1.55 × 1018 mol Ma−1 specifically during the EECO, ~ 4 to 37 % higher that the modern global volcanic CO2 output, owing to a dramatic India–Asia plate convergence increase. In addition to the background CO2 degassing, the subduction of thick Greater Indian continental margin carbonate sediments at ~ 55–50 Ma may also have led to additional CO2 production of 3.35 × 1018 mol Ma−1 during the EECO, making a total of 85 % of the global volcanic CO2 outgassed. However, climate modelling demonstrates that timing of maximum CO2 release only partially fit with the EECO, and that corresponding maximum pCO2 values (750 ppm and surface warming (+2 °C do not reach values inferred from geochemical proxies, a result consistent with conclusions arise from modelling based on other published CO2 fluxes. These results demonstrate that CO2 derived from decarbonation of Neo-Tethyan lithosphere may have possibly contributed to, but certainly cannot account alone for early Cenozoic warming, including the EECO. Other commonly cited sources of excess CO2 such as

  1. Did high Neo-Tethys subduction rates contribute to early Cenozoic warming?

    Science.gov (United States)

    Hoareau, G.; Bomou, B.; van Hinsbergen, D. J. J.; Carry, N.; Marquer, D.; Donnadieu, Y.; Le Hir, G.; Vrielynck, B.; Walter-Simonnet, A.-V.

    2015-12-01

    The 58-51 Ma interval was characterized by a long-term increase of global temperatures (+4 to +6 °C) up to the Early Eocene Climate Optimum (EECO, 52.9-50.7 Ma), the warmest interval of the Cenozoic. It was recently suggested that sustained high atmospheric pCO2, controlling warm early Cenozoic climate, may have been released during Neo-Tethys closure through the subduction of large amounts of pelagic carbonates and their recycling as CO2 at arc volcanoes. To analyze the impact of Neo-Tethys closure on early Cenozoic warming, we have modeled the volume of subducted sediments and the amount of CO2 emitted along the northern Tethys margin. The impact of calculated CO2 fluxes on global temperature during the early Cenozoic have then been tested using a climate carbon cycle model (GEOCLIM). We show that CO2 production may have reached up to 1.55 × 1018 mol Ma-1 specifically during the EECO, ~ 4 to 37 % higher that the modern global volcanic CO2 output, owing to a dramatic India-Asia plate convergence increase. The subduction of thick Greater Indian continental margin carbonate sediments at ~ 55-50 Ma may also have led to additional CO2 production of 3.35 × 1018 mol Ma-1 during the EECO, making a total of 85 % of the global volcanic CO2 outgassed. However, climate modeling demonstrates that timing of maximum CO2 release only partially fits with the EECO, and that corresponding maximum pCO2 values (750 ppm) and surface warming (+2 °C) do not reach values inferred from geochemical proxies, a result consistent with conclusions arising from modeling based on other published CO2 fluxes. These results demonstrate that CO2 derived from decarbonation of Neo-Tethyan lithosphere may have possibly contributed to, but certainly cannot account alone for early Cenozoic warming. Other commonly cited sources of excess CO2 such as enhanced igneous province volcanism also appear to be up to 1 order of magnitude below fluxes required by the model to fit with proxy data of pCO2 and

  2. New gliding mammaliaforms from the Jurassic

    Science.gov (United States)

    Meng, Qing-Jin; Grossnickle, David M.; Liu, Di; Zhang, Yu-Guang; Neander, April I.; Ji, Qiang; Luo, Zhe-Xi

    2017-08-01

    Stem mammaliaforms are Mesozoic forerunners to mammals, and they offer critical evidence for the anatomical evolution and ecological diversification during the earliest mammalian history. Two new eleutherodonts from the Late Jurassic period have skin membranes and skeletal features that are adapted for gliding. Characteristics of their digits provide evidence of roosting behaviour, as in dermopterans and bats, and their feet have a calcaneal calcar to support the uropagatium as in bats. The new volant taxa are phylogenetically nested with arboreal eleutherodonts. Together, they show an evolutionary experimentation similar to the iterative evolutions of gliders within arboreal groups of marsupial and placental mammals. However, gliding eleutherodonts possess rigid interclavicle-clavicle structures, convergent to the avian furculum, and they retain shoulder girdle plesiomorphies of mammaliaforms and monotremes. Forelimb mobility required by gliding occurs at the acromion-clavicle and glenohumeral joints, is different from and convergent to the shoulder mobility at the pivotal clavicle-sternal joint in marsupial and placental gliders.

  3. The role of Variscan to pre-Jurassic active extension in controlling the architecture of the rifted passive margin of Adria: the example of the Canavese Zone (Western Southern Alps, Italy)

    Science.gov (United States)

    Succo, Andrea; De Caroli, Sara; Centelli, Arianna; Barbero, Edoardo; Balestro, Gianni; Festa, Andrea

    2016-04-01

    The Canavese Zone, in the Italian Western Southern Alps, represents the remnant of the Jurassic syn-rift stretching, thinning and dismemberment of the distal passive margin of Adria during the opening of the Penninic Ocean (i.e., Northern Alpine Tethys). Our findings, based on detailed geological mapping, structural analysis and stratigraphic and petrographic observations, document however that the inferred hyper-extensional dismemberment of this distal part of the passive margin of Adria, up to seafloor spreading, was favored by the inherited Variscan geometry and crustal architecture of the rifted margin, and by the subsequent Alpine-related strike-slip deformation. The new field data document, in fact, that the limited vertical displacement of syn-extensional (syn-rift) Jurassic faults was ineffective in producing and justifying the crustal thinning observed in the Canavese Zone. The deformation and thinning of the continental basement of Adria are constrained to the late Variscan time by the unconformable overlying of Late Permian deposits. Late Cretaceous-Early Paleocene and Late Cenozoic strike-slip faulting (i.e., Alpine and Insubric tectonic stages) reactivated previously formed faults, leading to the formation of a complex tectonic jigsaw which only partially coincides with the direct product of the Jurassic syn-rift dismemberment of the distal part of the passive margin of Adria. Our new findings document that this dismemberment of the rifted continental margin of Adria did not simply result from the syn-rift Jurassic extension, but was strongly favored by the inheritance of older (Variscan and post-Variscan) tectonic stages, which controlled earlier lithospheric weakness. The formation of rifted continental margins by extension of continental lithosphere leading to seafloor spreading is a complex and still poorly understood component of the plate tectonic cycle. Geological mapping of rifted continental margins may thus provide significant information to

  4. Genesis of Yangla Banded Skarn-Hosted Copper Deposit in Tethys Orogenic Belt of Southwestern China

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Yangla copper deposit is the largest banded skarn-hosted copper deposit found recently in the Tethys orogenic belt of Southwestern China. On the basis of the study of distribution, petrology and mineralogy as well as major element, REE and isotope geochemistry, the authors find that the banded skarn, which hosts the deposit, was precipitated from hydrothermal solutions in the form of exhalate sediment. Therefore, the banded skarn-hosted copper deposit is a Sedex-type deposit, with a series of stacked, conformable lenses underlain by at least one stringer zone. The deposit, intercalated at the contact of lower clastic rock and upper carbonate rock of Gajinxueshan Group, was formed in the Carboniferous ((296.1±7.0) Ma), contemporary to the host Gajinxueshan Group. The interpretation of the genesis of Yangla banded skarn-hosted copper deposit is of fundamental exploration significance for the discovery of Sedex-type copper deposit in the region.

  5. Aridification of the Sahara desert caused by Tethys Sea shrinkage during the Late Miocene.

    Science.gov (United States)

    Zhang, Zhongshi; Ramstein, Gilles; Schuster, Mathieu; Li, Camille; Contoux, Camille; Yan, Qing

    2014-09-18

    It is widely believed that the Sahara desert is no more than ∼2-3 million years (Myr) old, with geological evidence showing a remarkable aridification of north Africa at the onset of the Quaternary ice ages. Before that time, north African aridity was mainly controlled by the African summer monsoon (ASM), which oscillated with Earth's orbital precession cycles. Afterwards, the Northern Hemisphere glaciation added an ice volume forcing on the ASM, which additionally oscillated with glacial-interglacial cycles. These findings led to the idea that the Sahara desert came into existence when the Northern Hemisphere glaciated ∼2-3 Myr ago. The later discovery, however, of aeolian dune deposits ∼7 Myr old suggested a much older age, although this interpretation is hotly challenged and there is no clear mechanism for aridification around this time. Here we use climate model simulations to identify the Tortonian stage (∼7-11 Myr ago) of the Late Miocene epoch as the pivotal period for triggering north African aridity and creating the Sahara desert. Through a set of experiments with the Norwegian Earth System Model and the Community Atmosphere Model, we demonstrate that the African summer monsoon was drastically weakened by the Tethys Sea shrinkage during the Tortonian, allowing arid, desert conditions to expand across north Africa. Not only did the Tethys shrinkage alter the mean climate of the region, it also enhanced the sensitivity of the African monsoon to orbital forcing, which subsequently became the major driver of Sahara extent fluctuations. These important climatic changes probably caused the shifts in Asian and African flora and fauna observed during the same period, with possible links to the emergence of early hominins in north Africa.

  6. Near-infrared (0.8-4.0 m) spectroscopy of mimas, enceladus, tethys, and rhea

    Science.gov (United States)

    Emery, J.P.; Burr, D.M.; Cruikshank, D.P.; Brown, R.H.; Dalton, J.B.

    2005-01-01

    Spectral measurements from the ground in the time leading up to the Cassini mission at Saturn provide important context for the interpretation of the forthcoming spacecraft data. Whereas ground-based observations cannot begin to approach the spatial scales Cassini will achieve, they do possess the benefits of better spectral resolution, a broader possible time baseline, and unique veiewing geometries not obtained by spacecraft (i.e., opposition). In this spirit, we present recent NIR reflectance spectra of four icy satellites of Saturn measured with the SpeX instrument at the IRTF. These measurements cover the range 0.8-4.0 m of both the leading and trailing sides of Tethys and the leading side of Rhea. The L-band region (2.8-4.0 m) offers new opportunities for searches of minor components on these objects. Additionally, these data include 0.8-2.5 m spectra of both the leading and trailing sides of Mimas and of the (mostly) trailing side of Enceladus. The spectrum of Enceladus shows activity near 2.25 m that we interpret as a possible signature of NH3 ice. The presence of ammonia in the Saturn system is not unexpected, and may help explain the apparent recent geologic activity of Enceladus. Analysis of leading/trailing differences inH2O band depths, spectral slopes, and albedo imply a separate regime of surface modification for Mimas and Enceladus than for the more distant icy satellites (Tethys, Dione, Rhea). Aside from the potential NH3 on Enceladus, no other minor constituents are detected in these icy surfaces.

  7. Permo-Triassic paleogeographic, paleoclimatic and paleoceanographic evolutions in eastern Tethys and their coupling

    Institute of Scientific and Technical Information of China (English)

    YAN; Jiaxin

    2001-01-01

    [1]Yang, Z. Y., Wu. S. B., Yin, H. E et al., Permo-Triassic Events of South China (in Chinese), Beijing: Geological Publishing House, 1991, 1-180.[2]Jin Y. G., Wang, Y.. Wang, W. et al., Pattern of marine mass extinction near the Permian-Triassic boundary in South China,Science, 2000, 289(5478): 432-36.[3]Ziegler. A. M., Michael, L., Hulver. M. L. et al., Permian world topography and climate, in Late Glacial and Postglacial Environmental Changes——Quaternary, Carboniferous-Permian and Proterozoic (ed., Maitini, I. P.), New York: Oxford Univ. Press, 1997, 111-146.[4]Crowley, T. J., Pangea climate, In Pangea: Paleoclimate, Tectonics and Sedimentation during Accretion, Zenith and Breakup of a Supercontinent (ed., Klein, G. D.), Colorado: Geological Society of America Special Paper 288, 1994,25-39.[5]Parrish, J. T., Climate of the supercontinent Pangea, The Journal of Geology, 1993, 101:215-233.[6]Ziegler. A. M., Phytogeographic patterns and continental configurations during the Permian Period, in Palaeozoic Palaeogeography and Biogeography (eds, McKerrow, W. S., Scotese, C. R.), London: Geological Society Memoir 12, 1990,363-379.[7]Yan, J. X., Liu, B. P., Zhang, H. Q., Palaeogeographic implications of Carboniferous to Permian oolitic limestones in the Changning-Menglian belt of west Yunnan, Journal of Palaeogeography (in Chinese), 1999,1 (3): 13-18.[8]Yin, H. F., Peng, Y. Q., The Triassic of China and its interregional correlation, in Permian-Triassic Evolution of Tethys and Western Circum-Pacific (eds., Yin, H. F., Dickins, J. M., Shi, G. R. et al.), Amsterdam: Elsevier, 2000, 197-220.[9]Yan. J. X.,Permian-Triassic paleoclimatic of eastern Tethys and its paleogeographic implication, Earth Science (in Chinese), 1999, 24(1): 13-20.[10]Yan, J. X., Yin, H. F., Paleoclimatic constraints for Early Permian paleogeography of eastern Tethys, In Permian-Triassic Evolution of Tethys and Western Circum-Pacific (eds., Yin, H, F., Dickins

  8. 3d Operational Hydrodinamic Modelling System as a Support to Oil Spill Responses in the Ligurian Sea (North-Western Mediterranean)

    Science.gov (United States)

    Del Giudice, T.; Quagliati, M.; Bertolotto, R.; Pedroncini, A.; Cusati, L. A.

    2014-12-01

    Accidental oil spills have a significant impact on marine ecosystems reminding us the importance of an efficiency emergency planning to ensure a quick and proper response. In this phase, the numerical modelling approach emerges as a useful tool in order to simulate the scenarios and addresses the issue of oil dispersion in the case of a spill. The 3D operational hydrodynamic modelling system of the Ligurian Sea (North-Western Mediterranean) is used as a base to predict the possible oil trajectory and to track the path and fate of spilled oil under the prevailing hydrodynamic and meteorological conditions. The operative chain of the hydrodynamic model was developed by DHI Italia for the Regional Environment Protection Agency (ARPAL) operating in the Ligurian region (Italy) with the objective to preserve the environment, support the activities of the Civil Protection Department and promote a sustainable, healthy and safety management of the local resources. In this chain the MFS Mediterranean 3D model (operated within MyOcean EU Project - Copernicus Programme) was downscaled from 6.5 km to finer nearshore mesh (500 m). The increased spatial resolution allows the correct simulation of current developments in the vicinity of morphological discontinuities such as the promontory of Portofino on the Ligurian coast. The meteorological forcing is provided by MOLOCH, a LAM model operated by ARPAL together with fresh water discharges from the main rivers through hydrological modelling. Since the Ligurian Sea recently hosted the transfer of wreck Costa Concordia some real time simulations of hypothetical oil spill were performed to support the crisis unit of the Genoa Coast Guard. Simulations led to interesting results concerning the importance of updated weather conditions, which strongly influence current trends, focusing on the importance of the continuity of the modelling chain.

  9. Schmeissneria: An angiosperm from the Early Jurassic

    Institute of Scientific and Technical Information of China (English)

    Xin WANG

    2010-01-01

    The origin of angiosperms has been a focus of intensive research for a long time. The so-called preCretaceous angiosperms, including Schmeissneria, are usually clouded with doubt. To expel the cloud around the enigmatic Schmeissneria, the syntype and new materials of Schmeissneria collected previously in Germany and recently in China are studied. These materials include female inflorescences and infructescences. The latter are old materials but were under-studied previously. Light microscopy and scanning electron microscope observations indicate that the fruits in these infructescences have in situ seeds enclosed, and that the ovaries are closed before pollination. Thus the plants meet two strict criteria for angiosperms: angiospermy plus angio-ovuly. Placing Schmeissneria in angiosperms will extend the record of angiosperms up to the Early Jurassic, more compatible with many molecular dating conclusions on the age of angiosperms, and demanding a reassessment of the current doctrines on the origin of angiosperms. Although the phylogenetic relationship of Schmeissneria to other angiosperms apparently is still an open question, this study adds to research concerning the origin of angiosperms.

  10. Web-Based Data Visualization and Analysis using HydroShare and the Open Source Tethys Platform

    Science.gov (United States)

    Ames, D. P.; Li, Z.; Qiao, X.; Tarboton, D. G.; Idaszak, R.; Horsburgh, J. S.; Merwade, V.; Miles, B.; Swain, N. R.; Lineberger, R.; Rice, E.

    2015-12-01

    HydroShare is a collaborative environment developed to make it easy for the hydrology community to share and publish data, models, and analytical tools. HydroShare is deployed at http://www.hydroshare.org/ with capabilities for uploading and publishing any type of hydrologic digital data as a Library of Congress-BagIt formatted digital "resource" object. Examples of supported hydrologic data resources include: geographic rasters, NetCDF multi-dimensional data, time series, model programs, and model instances. To support web-based visualization and analysis of these digital objects, we have deployed an instance of the open source Tethys Platform web app hosting system at http://apps.hydroshare.org/. Tethys is a web development platform that provides web application developers with a Python-based programming environment for building and hosting hydrologic "web apps" - loosely defined as single purpose, task-oriented, user-friendly, web-accessible applications. Tethys Platform includes an open source GIS software suite comprised of GeoServer, PostGIS, 52-North, GRASS, R, OpenLayers, HighCharts, and other useful tools to support custom web app development. This presentation will introduce the Web App resource type in HydroShare and its custom metadata elements - illustrating how we used HydroShare itself as a catalog for web apps. The approach uses loose coupling and web services to link HydroShare resources with web apps in a scalable way that can expand to third party web apps. Example Tethys-based web app resources presently available in HydroShare will be highlighted.

  11. Temporal variations of zooplankton biomass in the Ligurian Sea inferred from long time series of ADCP data

    Directory of Open Access Journals (Sweden)

    R. Bozzano

    2013-08-01

    Full Text Available Three years of 300 kHz ADCP data collected in the central Ligurian Sea are analyzed to investigate the variability of the zooplankton biomass and the Diel Vertical Migrations (DVM in the upper thermocline. After a pre-processing aimed at avoiding the slant range attenuation, hourly volume backscattering strength time series are obtained. Despite the lack of concurrent net samples collection, different migration patterns are identified and their temporal variability examined by means of time-frequency analysis. The effect of changes in the environmental condition is also investigated. Highest zooplankton biomasses are observed in April–May just after the peak of surface primary production in March–April. The main migration pattern points to a "nocturnal" migration with zooplankton organisms occurring deeper in the water column during the day and shallower at night. Also twilight migration is highlighted during this study. The largest migrations are recorded in November–December, corresponding to lowest backscattering strength values and are likely attributable to larger and more active organisms (i.e. euphausiids and mesopelagic fish. The results suggest further applications of the historical ADCP time series available.

  12. Spatial variation of deep diving odontocetes' occurrence around a canyon region in the Ligurian Sea as measured with acoustic techniques

    Science.gov (United States)

    Giorli, Giacomo; Neuheimer, Anna; Au, Whitlow

    2016-10-01

    Understanding the distribution of animals is of paramount importance for management and conservation, especially for species that are impacted by anthropogenic threats. In the case of marine mammals there has been a growing concern about the impact of human-made noise, in particular for beaked whales and other deep diving odontocetes. Foraging (measured via echolocation clicks at depth) was studied for Cuvier's beaked whale (Ziphius cavirostris), sperm whale (Physeter macrocephalus), long-finned pilot whales (Globicephala melas) and Risso's dolphin (Grampus griseus) using three passive acoustics recorders moored to the bottom of the ocean in a canyon area in the Ligurian Sea between July and December 2011. A Generalized Linear Model was used to test whether foraging was influenced by location and day of the year, including the possibility of interactions between predictors. Contrary to previous studies conducted by visual surveys in this area, all species were detected at all locations, suggesting habitat overlapping. However, significant differences were found in the occurrence of each species at different locations. Beaked and sperm whales foraged significantly more in the northern and western locations, while long-finned pilot whales and Risso's dolphins hunted more in the northern and eastern location.

  13. Differences in foraging activity of deep sea diving odontocetes in the Ligurian Sea as determined by passive acoustic recorders

    Science.gov (United States)

    Giorli, Giacomo; Au, Whitlow W. L.; Neuheimer, Anna

    2016-01-01

    Characterizing the trophic roles of deep-diving odontocete species and how they vary in space and time is challenged by our ability to observe foraging behavior. Though sampling methods are limited, foraging activity of deep-diving odontocetes can be monitored by recording their biosonar emissions. Daily occurrence of echolocation clicks was monitored acoustically for five months (July-December 2011) in the Ligurian Sea (Mediterranean Sea) using five passive acoustic recorders. Detected odontocetes included Cuvier's beaked whales (Zipuhius cavirostris), sperm whales (Physeter macrocephalus), Risso's dolphins (Grampus griseus), and long-finned pilot whales (Globicephala melas). The results indicated that the foraging strategies varied significantly over time, with sperm whales switching to nocturnal foraging in late September whereas Risso's dolphins and pilot whales foraged mainly at night throughout the sampling period. In the study area, winter nights are about five hours longer than summer nights and an analysis showed that pilot whales and Risso's dolphins adjusted their foraging activity with the length of the night, foraging longer during the longer winter nights. This is the first study to show that marine mammals exhibit diurnal foraging patterns closely correlated to sunrise and sunset.

  14. The Jurassic of Denmark and Greenland: Upper Jurassic – Lower Cretaceous of the Danish Central Graben: structural framework and nomenclature

    Directory of Open Access Journals (Sweden)

    Japsen, Peter

    2003-10-01

    Full Text Available The Danish Central Graben is part of the mainly Late Jurassic complex of grabens in the central and southern North Sea which form the Central Graben. The tectonic elements of the Danish Central Graben in the Late Jurassic are outlined and compared to those in the Early Cretaceous based on reduced versions of published maps (1:200 000, compiled on the basis of all 1994 public domain seismic and well data. The Tail End Graben, a half-graben which stretches for about 90 km along the East North Sea High, is the dominant Late Jurassic structural feature. The Rosa Basin (new name is a narrow, north-south-trending basin extending from the south-western part of the Tail End Graben. The Tail End Graben ceased to exist as a coherent structural element during the Early Cretaceous and developed into three separate depocentres: the Iris and Gulnare Basins to the north and the Roar Basin to the south (new names. The Early Cretaceous saw a shift from subsidence focused along the East North Sea High during the Late Jurassic to a more even distribution of minor basins within the Danish Central Graben. The depth to the top of the Upper Jurassic - lowermost Cretaceous Farsund Formation reaches a maximum of 4800 m in the northern part of the study area, while the depth to the base of the Upper Jurassic reaches 7500 m in the Tail End Graben, where the Upper Jurassic attains a maximum thickness of 3600 m. The Lower Cretaceous Cromer Knoll Group attains a maximum thickness of 1100 m in the Outer Rough Basin.

  15. The Tendaguru formation of southeastern Tanzania, East Africa: An alternating Late Jurassic to Early Cretaceous palaeoenvironment of exceptional status

    Science.gov (United States)

    Sames, B.

    2009-04-01

    Dinosaur remains have inspired considerable scientific interest in the Tendaguru formation of southeastern Tanzania during the 20th century; however, this formation is exceptional in many other respects. The Late Jurassic to Early Cretaceous deposits of the Tendaguru formation in the southwestern Tethys are unique because they represent a marginal marine palaeoenvironment with nonmarine faunal and floral content. It is a threefold succession of marginal marine to terrestrial, carbonate-siliciclastic sediments with cyclic character, consisting of three transgressive-regressive cycles. Revisitation of the type locality (the Tendaguru, a hill approximately 60km northwest of the town of Lindi) by a German-Tanzanian expedition in summer 2000 (Heinrich et al., 2001) resulted in a new standard section (hitherto unpublished, the informal terminology is indicated by the use of lower case in Tendaguru formation), a refined environmental model (Aberhan et al., 2002) and many new insights towards its geology (with evidence of event-sedimentation, Bussert and Aberhan, 2004), biostratigraphy and a better understanding of the Tendaguru palaeo-ecosystems and the palaeoclimate. Within the scope of the designation of a new standard section at the type locality, calcareous microfossils (ostracods, charophytes) have been described to supplement the ongoing discussion about the age and palaeoecology of the Tendaguru formation (Sames, 2008). Although only a few unevenly distributed layers across the section produced calcareous microfossils, the results are very promising. A total of 40 ostracode and 2 charophyte taxa could be distinguished. The non-marine part of the ostracod fauna provides an important contribution to the documentation of Purbeck/Wealden-type nonmarine palaeoenvironments and its microfaunas and -floras previously unknown from East Africa. The marine faunal part belongs to a relatively endemic southern (Gondwana) fauna. Together with other fossil groups, the

  16. Tethys and Dione as sources of outward-flowing plasma in Saturn's magnetosphere.

    Science.gov (United States)

    Burch, J L; Goldstein, J; Lewis, W S; Young, D T; Coates, A J; Dougherty, M K; André, N

    2007-06-14

    Rotating at over twice the angular speed of Earth, Saturn imposes a rapid spin on its magnetosphere. As a result, cold, dense plasma is believed to be flung outward from the inner magnetosphere by centrifugal force and replaced by hotter, more tenuous plasma from the outer magnetosphere. The centrifugal interchange of plasmas in rotating magnetospheres was predicted many years ago and was conclusively demonstrated by observations in Jupiter's magnetosphere, which--like that of Saturn (but unlike that of Earth)--is rotationally dominated. Recent observations in Saturn's magnetosphere have revealed narrow injections of hot, tenuous plasma believed to be the inward-moving portion of the centrifugal interchange cycle. Here we report observations of the distribution of the angle between the electron velocity vector and the magnetic field vector ('pitch angle') obtained in the cold, dense plasma adjacent to these inward injection regions. The observed pitch-angle distributions are indicative of outward plasma flow and consistent with centrifugal interchange in Saturn's magnetosphere. Further, we conclude that the observed double-peaked ('butterfly') pitch-angle distributions result from the transport of plasma from regions near the orbits of Dione and Tethys, supporting the idea of distinct plasma tori associated with these moons.

  17. Constraining central Neo-Tethys Ocean reconstructions with mantle convection models

    Science.gov (United States)

    Nerlich, Rainer; Colli, Lorenzo; Ghelichkhan, Siavash; Schuberth, Bernhard; Bunge, Hans-Peter

    2017-04-01

    A striking feature of the Indian Ocean is a distinct geoid low south of India, pointing to a regionally anomalous mantle density structure. Equally prominent are rapid plate convergence rate variations between India and SE Asia, particularly in Late Cretaceous/Paleocene times. Both observations are linked to the central Neo-Tethys Ocean subduction history, for which competing scenarios have been proposed. Here we evaluate three alternative reconstructions by assimilating their associated time-dependent velocity fields in global high-resolution geodynamic Earth models, allowing us to predict the resulting seismic mantle heterogeneity and geoid signal. Our analysis reveals that a geoid low similar to the one observed develops naturally when a long-lived back-arc basin south of Eurasia's paleomargin is assumed. A quantitative comparison to seismic tomography further supports this model. In contrast, reconstructions assuming a single northward dipping subduction zone along Eurasia's margin or models incorporating a temporary southward dipping intraoceanic subduction zone cannot sufficiently reproduce geoid and seismic observations.

  18. The Sahara from the Middle Jurassic to the Middle Cretaceous: Data on environments and climates based on outcrops in the Algerian Sahara

    Science.gov (United States)

    Busson, G.; Cornée, A.

    The period investigated, succeeded the Upper Triassic and Liassic-Lower Dogger arid sedimentation which was characterized by the development of large evaporitic deposits. The north-eastern part of the Algerian Sahara is specially interesting as it constitutes part of the few dated continental Jurassic outcrops in North Africa (except in the Maghreb). Continental Lower-Middle Cretaceous is also well developed in the same region. The grading of these continental series into marine series particularly in the north-eastern part of the Maghreb has been investigated from an adequate number of well spaced wells. The Middle-Upper Jurassic (Lower Taouratine) consists of an argillaceous-sandy-ferruginous series, often grey coloured and rich in filicean wood and vertebrate remains in some levels. The ferralitic alteration products denote a more humid climate than that which prevailed during the Liassic-Lower-Dogger times. These products alternate with sandy conglomeratic events confirming the influences of alternating important run-off and aeolian winnowing. The large continental Lower and Middle Cretaceous detrital nappes are discussed. They constitute the uppermost part of the series, south of the Tinrhert Hamada (Alba-Vraconian series with the more detrital lateral equivalent), west of Tademait (Gara Samani). Data on lithology and paleobiology (fishes, Dinosaurs, other vertebrates, pelecypods, gastropods, wood debris, palynoflora) permit the reconstruction of the palaeo-environment and the conditions of deposition. This is similar to the sub-desertic terrestrial sedimentation by violent and ephemeral hydrodynamism model based on the modern Darfour example. The desertic conditions which prevailed in these Saharan areas during the Cretaceous are reflected as well as their possible consequences on the sedimentation of nearby oceanic areas (Atlantic and Tethys). This detrital sedimentation is finally reviewed in the context of its tectonic origins and an attempt is made to

  19. Inheritance of Jurassic rifted margin architecture into the Apennines Neogene mountain building: a case history from the Lucretili Mts. (Latium, Central Italy)

    Science.gov (United States)

    Bollati, Andrea; Corrado, Sveva; Marino, Maurizio

    2012-06-01

    The western Lucretili Mts. in the central Apennines (Latium, Italy) have been recently re-mapped in great detail and are the subject of combined stratigraphic, sedimentological and structural investigations. In this paper, we present a new stratigraphic interpretation of the Jurassic paleogeography of western Lucretili Mts., where a rift-derived intrabasinal paleo-high of the Alpine Tethys has been identified for the first time by means of facies analysis and biostratigraphic dating. Recognised facies associations, combined with dated stratigraphic sections, allow to define the morphology of the structural paleo-high and to identify the associated gravity-driven deposits (olistoliths) accumulated in the surrounding basin. Furthermore, we investigated the modes of interaction between Jurassic extensional structures and the subsequent contractional patterns developed during the Tertiary mountain building. In detail, the role played during Apennines tectonics by the paleo-escarpments bounding the paleo-high and by the surrounding olistoliths has been analysed. The paleo-escarpments either acted as focussing features for ENE-directed frontal thrust ramp localisation and were offset with small shortening amounts or reactivated as NNE striking high angle transpressional faults or preserved the original geometries as a result of variable orientation of paleo-escarpments with respect to the Neogene compressive stress field (with ENE oriented sigma1). Newly formed ENE striking tear faults connect these either inherited or neo-formed discontinuities. This complex stratigraphic and structural pattern is substantially different from the previous interpretations of this portion of the central Apennines based on a hypothesised layer-cake stratigraphy deformed by neo-formed Neogene thrusts. This contribution strengthens the importance of integrating facies analyses and structural investigations to detect the influence of pre-orogenic structures on compressive structural patterns

  20. Fauna and predator-prey relationships of Ettling, an actinopterygian fish-dominated Konservat-Lagerstatte from the Late Jurassic of southern Germany.

    Directory of Open Access Journals (Sweden)

    Martin Ebert

    Full Text Available The newly recognized Konservat-Lagerstätte of Ettling (Bavaria, field site of the Jura-Museum Eichstätt (JME, is unique among Late Jurassic plattenkalk basins (Solnhofen region in its abundant, extremely well preserved fossil vertebrates, almost exclusively fishes. We report actinopterygians (ginglymodins, pycnodontiforms, halecomorphs, aspidorynchiforms, "pholidophoriforms," teleosts; turtles; and non-vertebrates (echinoderms, arthropods, brachiopods, mollusks, jellyfish, sponges, biomats, plants in a current faunal list. Ettling has yielded several new fish species (Bavarichthys incognitus; Orthogonikleithrus hoelli; Aspidorhynchus sanzenbacheri; Macrosemimimus fegerti. Upper and lower Ettling strata differ in faunal content, with the lower dominated by the small teleost Orthogonikleithrus hoelli (absent from the upper layers, where other prey fishes, Leptolepides sp. and Tharsis sp., occur instead. Pharyngeal and stomach contents of Ettling fishes provide direct evidence that Orthogonikleithrus hoelli was a primary food source during early Ettling times. Scarcity of ammonites and absence of vampyromorph coleoids at Ettling differ markedly from the situation at other nearby localities in the region (e.g., Eichstätt, Painten, Schamhaupten, the Mörnsheim beds, where they are more common. Although the exact biochronological age of Ettling remains uncertain (lack of suitable index fossils, many Ettling fishes occur in other plattenkalk basins of Germany (e.g., Kelheim and France (Cerin dated as Late Kimmeridgian to Early Tithonian (eigeltingense horizon, suggesting a comparable geologic age. The Ettling deposits represent an independent basin within the larger Upper Jurassic "Solnhofen Archipelago", a shallow subtropical sea containing scattered islands, sponge-microbial and coral reefs, sandbars, and deeper basins on a vast carbonate platform along the northern margin of the Tethys Ocean.

  1. Fauna and predator-prey relationships of Ettling, an actinopterygian fish-dominated Konservat-Lagerstätte from the Late Jurassic of southern Germany.

    Science.gov (United States)

    Ebert, Martin; Kölbl-Ebert, Martina; Lane, Jennifer A

    2015-01-01

    The newly recognized Konservat-Lagerstätte of Ettling (Bavaria), field site of the Jura-Museum Eichstätt (JME), is unique among Late Jurassic plattenkalk basins (Solnhofen region) in its abundant, extremely well preserved fossil vertebrates, almost exclusively fishes. We report actinopterygians (ginglymodins, pycnodontiforms, halecomorphs, aspidorynchiforms, "pholidophoriforms," teleosts); turtles; and non-vertebrates (echinoderms, arthropods, brachiopods, mollusks, jellyfish, sponges, biomats, plants) in a current faunal list. Ettling has yielded several new fish species (Bavarichthys incognitus; Orthogonikleithrus hoelli; Aspidorhynchus sanzenbacheri; Macrosemimimus fegerti). Upper and lower Ettling strata differ in faunal content, with the lower dominated by the small teleost Orthogonikleithrus hoelli (absent from the upper layers, where other prey fishes, Leptolepides sp. and Tharsis sp., occur instead). Pharyngeal and stomach contents of Ettling fishes provide direct evidence that Orthogonikleithrus hoelli was a primary food source during early Ettling times. Scarcity of ammonites and absence of vampyromorph coleoids at Ettling differ markedly from the situation at other nearby localities in the region (e.g., Eichstätt, Painten, Schamhaupten, the Mörnsheim beds), where they are more common. Although the exact biochronological age of Ettling remains uncertain (lack of suitable index fossils), many Ettling fishes occur in other plattenkalk basins of Germany (e.g., Kelheim) and France (Cerin) dated as Late Kimmeridgian to Early Tithonian (eigeltingense horizon), suggesting a comparable geologic age. The Ettling deposits represent an independent basin within the larger Upper Jurassic "Solnhofen Archipelago", a shallow subtropical sea containing scattered islands, sponge-microbial and coral reefs, sandbars, and deeper basins on a vast carbonate platform along the northern margin of the Tethys Ocean.

  2. Harvestmen (Arachnida: Opiliones) from the Middle Jurassic of China

    Science.gov (United States)

    Huang, Diying; Selden, Paul A.; Dunlop, Jason A.

    2009-08-01

    Harvestmen (Arachnida: Opiliones) are familiar animals in most terrestrial habitats but are rare as fossils, with only a handful of species known from each of the Palaeozoic, Mesozoic, and Cenozoic eras. Fossil harvestmen from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China, are described as Mesobunus martensi gen. et sp. nov. and Daohugopilio sheari gen. et sp. nov.; the two genera differ primarily in the relative length of their legs and details of the pedipalps. Jurassic arachnids are extremely rare and these fossils represent the first Jurassic, and only the fourth Mesozoic, record of Opiliones. These remarkably well-preserved and modern-looking fossils are assigned to the Eupnoi, whereby M. martensi demonstrably belongs in Sclerosomatidae. It thus represents the oldest record of a modern harvestman family and implies a high degree of evolutionary stasis among one of the most widespread and abundant groups of long-legged, round-bodied harvestmen.

  3. On the occurrence and implications of Jurassic primary continental boninite-like melts in the Zagros orogen

    Science.gov (United States)

    Esna-Ashari, A.; Tiepolo, M.; Hassanzadeh, J.

    2016-08-01

    Ultramafic rocks, ranging from pyroxenites to hornblendites, are associated with granitoids of the Aligoodarz intrusive complex in the central Sanandaj-Sirjan Zone, representing the Mesozoic continental arc segment of the Zagros orogen. As inferred from the ultramafic whole rock composition and the most primitive clinopyroxene composition in pyroxenites, the geochemical signature of primary melt is significantly different from that of the continental arc basalts. In particular, primary melt is characterized by extremely low concentrations of incompatible elements and high concentrations of Mg and refractory elements typical of boninites. Amphibole is a late crystallizing mineral in these rocks and is in textural and chemical disequilibrium with olivine + orthopyroxene + clinopyroxene. Amphibole crystallized from a liquid underwent differentiation through a process of melt-rock reaction. In particular, early differentiated boninitic cumulates reacted with later melts with a strong crustal signature similar to Aligoodarz granodiorite. Usbnd Pb zircon geochronology from ultramafic rocks and surrounding quartz-diorite yield similar ages and indicate that they are coeval with Aligoodarz granitoids (ca. 165-170 Ma). However, the occurrence of a marked negative Eu anomaly in zircon from the ultramafic rocks, which is absent in the boninitic primary melt, indicates that zircons crystallized from the infiltrating melt and in turn date the timing of melt infiltration. The interaction between ultramafic cumulates and infiltrated melt has generated a new liquid compositionally similar to high-Mg andesites and to the quartz-diorites hosting the ultramafic cumulates. The scenario that better account for the genesis of boninitic melts in the Sanandaj-Sirjan Zone is partial melting of a depleted mantle wedge in response to the onset of NeoTethys subduction. According to this hypothesis, middle Jurassic calc-alkaline magmatism in the Sanandaj-Sirjan Zone represents the mature stage

  4. The second Jurassic dinosaur rush and the dawn of dinomania.

    Science.gov (United States)

    Brinkman, Paul D

    2010-09-01

    During the second Jurassic dinosaur rush museum paleontologists raced to display the world's first mounted sauropod dinosaur. The American Museum of Natural History triumphed in 1905 when its Brontosaurus debuted before an admiring crowd of wealthy New Yorkers. The Carnegie Museum of Natural History in Pittsburgh, the Field Columbian Museum in Chicago and other institutions were quick to follow with their own sauropod displays. Thereafter, dinomania spread far and wide, and big, showpiece dinosaurs became a museum staple. This brief but intensely competitive period of acquisitiveness fostered important Jurassic dinosaur revisions and crucial innovations in paleontological field and lab techniques.

  5. Jurassic domes in the North Sea - northern North Atlantic region

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Geological Inst., Copenhagen (Denmark)

    1996-12-31

    The stratigraphic and tectonic evolution of the Jurassic of East Greenland, the Norwegian Shelf and the North Sea is remarkably similar. A major Middle Jurassic unconformity occurs in all three areas. In the North Sea it is commonly termed the `Mid-Cimmerian Unconformity` and is characterized by progressive truncation of the underlying section towards a centre at the triple junction between the Central Graben, Viking Graben and Moray Firth. Strata above the unconformity show a progressive Late Aalenian-Early Kimmeridgian onlap in the same direction. These relations have been interpreted as caused by Early Jurassic uplift and of a major thermal dome in the central North Sea, followed by Medial and Late Jurassic rifting, erosion, deflation and transgression of the dome. The East Greenland unconformity shows progressive truncation of underlying strata from south to north, and Bajocian to Callovian onlap in the same direction. The same pattern seems to be developed on the conjugate Norwegian margin. This suggests the possibility that the three unconformities have similar causes for their development. It is proposed that major rift domes formed in the Central North Sea and in the Greenland-Norway seaway in Early Jurassic times. The domes were eroded and gradually deflated during Medial Jurassic times and were finally submerged by the Late Oxfordian-Kimmeridgian. They were associated with volcanism and rifting which was delayed with respect to dome initiation. Roughly contemperaneous domes were present west of Britain, north of the Porcupine Seabight, and in Scania, southern Sweden, as reflected by development of asymmetrical unconformities showing progressive truncation of underlying strata, onlap of overlying Jurassic strata, and associated intrusive and extrusive volcanism. The domes are related to impingement of the heads of transient mantle plumes at the base of the lithosphere. The associated unconformities are thus of non-eustatic nature. Domal uplift and

  6. Jurassic Tectonics of North China: A Synthetic View

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yueqiao; DONG Shuwen; ZHAO Yue; ZHANG Tian

    2008-01-01

    This paper gives a synthetic view on the Jurassic tectonics of North China, with an attempt to propose a framework for the stepwise tectonic evolution history. Jurassic sedimentation, deformation and magmatism in North China have been divided into three stages. The earliest Jurassic is marked by a period of magmatism quiescence (in 205-190 Ma) and regional uplift, which are considered to be the continuation of the "Indosinian movement" characterized by continent-continent collision between the North and South China blocks. The Early to Middle Jurassic (in 190-170 Ma) was predominated by weak lithospheric extension expressed by mantle-derived plutonism and volcanism along the Yanshan belt and alongside the Tan-Lu fault zone, normal faulting and graben formation along the Yinshan-Yanshan tectonic belt, depression and resuming of coal-bearing sedimentation in vast regions of the North China block (NCB). The Middle to Late Jurassic stage started at 165,.5 Ma and ended up before 136 Ma; it was dominated by intensive intraplate deformation resulting from multi-directional compressions. Two major deformation events have been identified. One is marked by stratigraphic unconformity beneath the thick Upper Jurassic molasic series in the foreland zones of the western Ordos thrust-fold belt and along the Yinshan-Yanshan belt; it was predated 160 Ma. The other one is indicated by stratigraphic unconformity at the base of the Lower Cretaceous and predated 135 Ma. During this last stage, two latitudinal tectonic belts, the Yinshan-Yanshan belt in the north and the Qinling-Dabie belt in the south, and the western margin of the Ordos basin were all activated by thrusting; the NCB itself was deformed by the NE to NNE-trending structural system involving thrusting, associated folding and sinistral strike-slip faulting, which were spatially partitioned. Foliated S-type granitic plutons aged 160-150 Ma were massively emplaced in the Jiao-Liao massif east of the Tan-Lu fault zone and

  7. The sequence of moderate-size earthquakes at the junction of the Ligurian basin and the Corsica margin (western Mediterranean): The initiation of an active deformation zone revealed?

    Science.gov (United States)

    Larroque, Christophe; Delouis, Bertrand; Sage, Françoise; Régnier, Marc; Béthoux, Nicole; Courboulex, Françoise; Deschamps, Anne

    2016-04-01

    A new seismically active zone is found in the southern part of the Ligurian basin, 80-km west of Corsica (western Mediterranean). The activity began in February 2011 with a foreshock (ML 4) and a mainshock (ML 5.3) 5 days later, followed by numerous aftershocks. We first analyze the fore- and mainshock in detail. We compare the results obtained using classical methods (linear location in a 1D medium and focal mechanisms from P and S polarities) and new approaches (non-linear location in a 3D medium and waveform modeling for determining the seismic moment and the focal mechanism). Both methods provided similar results for location, depth (in the range of 6-13 km) and focal mechanisms, which reveal reverse faulting with nodal planes oriented N-S and NE-SW. We then locate 27 of the aftershocks in the 3D model and find a 10-km-long NE-SW alignment with a depth between 7 and 16 km. In 2012 and 2013, three other moderate-size events (ML 3.8, 4 and 4.5) occurred and confirm that this zone is still active. The epicentral area is located in the oceanic domain of the Ligurian Basin. From analysis of the bathymetry and high-resolution multi-channel seismic profiles, no morphologic anomaly at surface and no inherited fault in the shallow ~ 4 km depth were imaged, which suggest that no significant deformation occurred in the area since 5 Ma. Thus, the structure(s) activated during the 2011-2013 sequence remain unknown. In light of these results, we point out a notable difference on both sides of the Ligurian Basin: the northern margin, close to the alpine chain, suffered strong earthquakes and large cumulated deformation since 5 Ma, while the southern margin, close to the Corsica-Sardinia continental block, is poorly deformed since 5 Ma.

  8. From rifting to passive margin: the examples of the Red Sea, Central Atlantic and Alpine Tethys

    Science.gov (United States)

    Favre, P.; Stampfli, G. M.

    1992-12-01

    Evolution of the Red Sea/Gulf of Suez and the Central Atlantic rift systems shows that an initial, transtensive rifting phase, affecting a broad area around the future zone of crustal separation, was followed by a pre-oceanic rifting phase during which extensional strain was concentrated on the axial rift zone. This caused lateral graben systems to become inactive and they evolved into rift-rim basins. The transtensive phase of diffuse crustal extension is recognized in many intra-continental rifts. If controlling stress systems relax, these rifts abort and develop into palaeorifts. If controlling stress systems persist, transtensive rift systems can enter the pre-oceanic rifting stage, during which the rift zone narrows and becomes asymmetric as a consequence of simple-shear deformation at shallow crustal levels and pure shear deformation at lower crustal and mantle-lithospheric levels. Preceding crustal separation, extensional denudation of the lithospheric mantle is possible. Progressive lithospheric attenuation entails updoming of the asthenosphere and thermal doming of the rift shoulders. Their uplift provides a major clastic source for the rift basins and the lateral rift-rim basins. Their stratigraphic record provides a sensitive tool for dating the rift shoulder uplift. Asymmetric rifting leads to the formation of asymmetric continental margins, corresponding in a simple-shear model to an upper plate and a conjugate lower plate margin, as seen in the Central Atlantic passive margins of the United States and Morocco. This rifting model can be successfully applied to the analysis of the Alpine Tethys palaeo-margins (such as Rif and the Western Alps).

  9. Microstructures of Early Jurassic (Toarcian) shales of Northern Europe

    NARCIS (Netherlands)

    Houben, M.E.; Barnhoorn, A.; Wasch, L.; Trabucho-Alexandre, João; Peach, C.J.; Drury, M.R.

    2016-01-01

    The Toarcian (Early Jurassic) Posidonia Shale Formation is a possible unconventional gas source in Northern Europe and occurs within the Cleveland Basin (United Kingdom), the Anglo-Paris Basin (France), the Lower Saxony Basin and the Southwest Germany Basin (Germany), and the Roer Valley Graben, the

  10. Evidence for a Mid-Jurassic Adaptive Radiation in Mammals.

    Science.gov (United States)

    Close, Roger A; Friedman, Matt; Lloyd, Graeme T; Benson, Roger B J

    2015-08-17

    A series of spectacular discoveries have transformed our understanding of Mesozoic mammals in recent years. These finds reveal hitherto-unsuspected ecomorphological diversity that suggests that mammals experienced a major adaptive radiation during the Middle to Late Jurassic. Patterns of mammalian macroevolution must be reinterpreted in light of these new discoveries, but only taxonomic diversity and limited aspects of morphological disparity have been quantified. We assess rates of morphological evolution and temporal patterns of disparity using large datasets of discrete characters. Rates of morphological evolution were significantly elevated prior to the Late Jurassic, with a pronounced peak occurring during the Early to Middle Jurassic. This intense burst of phenotypic innovation coincided with a stepwise increase in apparent long-term standing diversity and the attainment of maximum disparity, supporting a "short-fuse" model of early mammalian diversification. Rates then declined sharply, and remained significantly low until the end of the Mesozoic, even among therians. This supports the "long-fuse" model of diversification in Mesozoic therians. Our findings demonstrate that sustained morphological innovation in Triassic stem-group mammals culminated in a global adaptive radiation of crown-group members during the Early to Middle Jurassic.

  11. Klukiopsis jurassica--A new Jurassic schizaeaceous fern from China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new Jurassic schizaeaceous fern Klukiopsis jurassica gen. et sp. nov. from Yima, Henan Province, China is described. The new fern is characterized by the abaxial sori arranged in two rows, apical and complete annulus and more than 800 smooth trilete spores in each sorus.

  12. Jurassic Park as a Teaching Tool in the Chemistry Classroom.

    Science.gov (United States)

    Jollis, W. Gary, Jr.

    1996-01-01

    Describes how the science fiction novel "Jurassic Park" has been used to provide the focus for summate discussions among gifted high school students participating in a state-sponsored, science-intensive summer program. Discusses adaptations of this approach for use in chemistry classes from the high school to intermediate college level. (JRH)

  13. In situ Gymnosperm pollen from the Middle Jurassic of Yorkshire

    NARCIS (Netherlands)

    Konijnenburg-van Cittert, van Johanna H.A.

    1971-01-01

    In this paper the morphology of pollen grains yielded by male Gymnosperm fructifications from the Jurassic flora of Yorkshire is studied and discussed. Several new male fructifications were found and described: Hastystrobus gen. nov. was erected for male cones yielding the Eucommiidites type of poll

  14. The Cotoncello Shear Zone (Elba Island, Italy): The deep root of a fossil oceanic detachment fault in the Ligurian ophiolites

    Science.gov (United States)

    Frassi, Chiara; Musumeci, Giovanni; Zucali, Michele; Mazzarini, Francesco; Rebay, Gisella; Langone, Antonio

    2017-05-01

    The ophiolite sequences in the western Elba Island are classically interpreted as a well-exposed ocean-floor section emplaced during the Apennines orogeny at the top of the tectonic nappe-stack. Stratigraphic, petrological and geochemical features indicate that these ophiolite sequences are remnants of slow-ultraslow spreading oceanic lithosphere analogous to the present-day Mid-Atlantic Ridge and Southwest Indian Ridge. Within the oceanward section of Tethyan lithosphere exposed in the Elba Island, we investigated for the first time a ​10s of meters-thick structure, the Cotoncello Shear Zone (CSZ), that records high-temperature ductile deformation. We used a multidisciplinary approach to document the tectono-metamorphic evolution of the shear zone and its role during spreading of the western Tethys. In addition, we used zircon U-Pb ages to date formation of the gabbroic lower crust in this sector of the Apennines. Our results indicate that the CSZ rooted below the brittle-ductile transition at temperature above 800 °C. A high-temperature ductile fabric was overprinted by fabrics recorded during progressive exhumation up to shallower levers under temperature < 500 °C. We suggest that the CSZ may represent the deep root of a detachment fault that accomplished exhumation of an ancient oceanic core complex (OCC) in between two stages of magmatic accretion. We suggest that the CSZ represents an excellent on-land example enabling to assess relationships between magmatism and deformation when extensional oceanic detachments are at work.

  15. Trans-border (east Serbia/west Bulgaria correlation of the Jurassic sediments: Main Jurassic paleogeographic units

    Directory of Open Access Journals (Sweden)

    Tchoumatchenco Platon

    2006-01-01

    Full Text Available In the region across the Serbian/Bulgarian state border, there are individualized 5 Jurassic paleogeographic units (from West to East: (1 the Thracian Massif Unit without Jurassic sediments; (2 the Lužnica-Koniavo Unit - partially with Liassic in Grsten facies and with deep water Middle Callovian-Kimmeridgian (p. p sediments of the type "ammonitico rosso", and Upper Kimmeridgian-Tithonian siliciclastics flysch; (3 The Getic Unit subdivided into two subunits - the Western Getic Sub-Uni - without Lower Jurassic sediments and the Eastern Getic Sub-Unit with Lower Jurassic continental and marine sediments, which are followed in both sub-units by carbonate platform limestones (type Stramberk; (4 the Infra (Sub-Getic Unit - with relatively deep water Liassic and Dogger sediments (the Dogger of type "black shales with Bossitra alpine" and Middle Callovian-Tithonian of type "ammonitico rosso"; (5 the Danubian Unit - with shallow water Liassic, Dogger and Malm (Miroč-Vrška Čuka Zone, deep water Dogger and Malm (Donjomilanovačko-Novokoritska Zone.

  16. Impact of Cretaceous Climate on Upwelling and Erosive Capacity of Transequatorial Current in the Tethys Seaway - Tales from Deep-Sea Sediments

    Science.gov (United States)

    Weissert, H.; Wohlwend, S.

    2014-12-01

    Early Cretaceous sedimentary archives from the Atlantic and Tethys Ocean record a reorganization of ocean circulation triggered by a further opening and deepening oft the Hispanic corridor. Nannofossil ooze, deposited in Atlantic and Tethys Oceans during earliest Cretaceous mirrors a stable equatorial circulation pattern with oligotrophic surface water conditions. Tethyan limestone-marlstone deposits and dark clays in the western North Atlantic mark reorganization of circulation pattern dominating Valanginian-Albian oceanography and favoring episodic black shale formation in Atlantic and Tethys Ocean. An east-west directed trans-equatorial current (TEC), coupled with equatorial upwelling and with varying erosive capacity was established (Hotinski and Toggweiler, Paleoceanography, 2003). Aptian sedimentary records from Tethys and Atlantic Oceans provide information on the sensitivity of the TEC to changing climate at times of perturbed carbon cycling as registered in the carbon isotope record. A greenhouse pulse defines the base of Aptian Oceanic Anoxic Event (OAE) 1a, while available temperature and pCO2 records point at post-OAE1a cooling of climate. In the eastern Tethys (Oman Mts), the Aptian greenhouse pulse coincides with onset of chert deposits at a time of a shallowing CCD and of increased upwelling. Well-ventilated Pacific-type deep-water conditions prevented the formation of black shales in the deep Hawasina Basin (Oman Mts). Low oxygen or anoxic conditions, however, favored black shale formation in basinal settings of the Western Tethys and Atlantic Ocean. Frequent sedimentary gaps in basinal successions and erosive surfaces, sometimes phosphatized, on alpine Tethyan submarine highs and along the Northern Tethyan shelf provide evidence for increased erosive power of the TEC, reaching depths of up to 1000m or more. If increased erosive power of TEC was triggered by the greenhouse pulse or by post-OAE1a cooling remains to be tested.

  17. Western Tethys continental-marine responses to the Carnian Humid Episode: Palaeoclimatic and palaeogeographic implications

    Science.gov (United States)

    López-Gómez, J.; Escudero-Mozo, M. J.; Martín-Chivelet, J.; Arche, A.; Lago, M.; Galé, C.

    2017-01-01

    This case-study examines correlations in the continental-marine sedimentary record for the Late Triassic Carnian Humid Episode in the western Tethys domain of present-day E Spain and islands of Majorca and Minorca. The study area was divided into five sectors from west to east. Sectors 1 to 3 comprise the continental sedimentary record of this humid episode in eastern Iberia, which is represented by the three subunits (K-2.1, K-2.2 and K-2.3) of the K-2 Fm or Manuel Fm; each subunit records a fluvial episode with marine intercalations in distal areas. Sector 4 corresponds to Majorca Island and represents volcaniclastic input into a marginal continental-marine transitional environment. Finally, sector 5 on Minorca Island comprises a karst surface developed on middle ramp deposits of the Arenal d'en Castell Fm, and separating this formation from the overlying Fontanelles Fm. Based on the ages of the units, estimated through palynomorph assemblages and ammonites, the Carnian Humid Episode was located in both the continental and marine sedimentary records. A detailed sedimentary study focused on facies analysis identified allogenic controls on both continental and marine records. Hence, in continental areas influenced by sea-level fluctuations, fluvial deposits appear integrated within standard lowstand, transgressive and highstand system tracts. This connection based on sedimentary sequences and unit ages indicates that subunits K-2.1 and K-2.2 are represented by a karst surface on the subaerially exposed shallow marine deposits, while subunit K-2.3 already reflects a return to the normal Late Triassic semi-arid to arid conditions that laterally correspond to the transgressive stage represented by the Fontanelles Fm in sector 5. Late Triassic tectonics activated previously developed N·NE-S·SW and NW-SE conjugate fault lineaments in eastern Iberia. This rifting episode controlled sedimentation in sectors 1 to 3, allowing volcanic activity at the fault lineaments

  18. Carbonation of subduction-zone serpentinite (high-pressure ophicarbonate; Ligurian Western Alps) and implications for the deep carbon cycling

    Science.gov (United States)

    Scambelluri, Marco; Bebout, Gray E.; Belmonte, Donato; Gilio, Mattia; Campomenosi, Nicola; Collins, Nathan; Crispini, Laura

    2016-05-01

    Much of the long-term carbon cycle in solid earth occurs in subduction zones, where processes of devolatilization, partial melting of carbonated rocks, and dissolution of carbonate minerals lead to the return of CO2 to the atmosphere via volcanic degassing. Release of COH fluids from hydrous and carbonate minerals influences C recycling and magmatism at subduction zones. Contradictory interpretations exist regarding the retention/storage of C in subducting plates and in the forearc to subarc mantle. Several lines of evidence indicate mobility of C, of uncertain magnitude, in forearcs. A poorly constrained fraction of the 40-115 Mt/yr of C initially subducted is released into fluids (by decarbonation and/or carbonate dissolution) and 18-43 Mt/yr is returned at arc volcanoes. Current estimates suggest the amount of C released into subduction fluids is greater than that degassed at arc volcanoes: the imbalance could reflect C subduction into the deeper mantle, beyond subarc regions, or storage of C in forearc/subarc reservoirs. We examine the fate of C in plate-interface ultramafic rocks, and by analogy serpentinized mantle wedge, via study of fluid-rock evolution of marble and variably carbonated serpentinite in the Ligurian Alps. Based on petrography, major and trace element concentrations, and carbonate C and O isotope compositions, we demonstrate that serpentinite dehydration at 2-2.5 GPa, 550 °C released aqueous fluids triggering breakdown of dolomite in nearby marbles, thus releasing C into fluids. Carbonate + olivine veins document flow of COH fluids and that the interaction of these COH fluids with serpentinite led to the formation of high-P carbonated ultramafic-rock domains (high-P ophicarbonates). We estimate that this could result in the retention of ∼0.5-2.0 Mt C/yr in such rocks along subduction interfaces. As another means of C storage, 1 to 3 km-thick layers of serpentinized forearc mantle wedge containing 50 modal % dolomite could sequester 1.62 to

  19. Habitat use and preferences of cetaceans along the continental slope and the adjacent pelagic waters in the western Ligurian Sea

    Science.gov (United States)

    Azzellino, A.; Gaspari, S.; Airoldi, S.; Nani, B.

    2008-03-01

    The physical habitat of cetaceans occurring along the continental slope in the western Ligurian Sea was investigated. Data were collected from two different sighting platforms, one of the two being a whale-watching boat. Surveys, conducted from May to October and from 1996 to 2000, covered an area of approximately 3000 km 2 with a mean effort of about 10,000 km year -1. A total of 814 sightings was reported, including all the species occurring in the area: Stenella coeruleoalba, Balaenoptera physalus, Physeter macrocephalus, Globicephala melas, Grampus griseus, Ziphius cavirostris, Tursiops truncatus, Delphinus delphis. A Geographic Information System was used to integrate sighting data to a set of environmental characteristics, which included bottom gradient, area between different isobaths, and length and linearity of the isobaths within a cell unit. Habitat use was analysed by means of a multi-dimensional scaling, MDS, analysis. Significant differences were found in the habitat preference of most of the species regularly occurring in the area. Bottlenose dolphin, Risso's dolphin, sperm whale and Cuvier's beaked whale were found strongly associated to well-defined depth and slope gradient characteristics of the shelf-edge and the upper and lower slope. The hypothesis of habitat segregation was considered for Risso's dolphin, sperm whale and Cuvier's beaked whale. Canonical discriminant functions using depth and slope as predictors outlined clear and not overlapping habitat preferences for Risso's dolphin and Cuvier's beaked whale, whereas a partial overlapping of the habitat of the other two species was observed for sperm whale. Such a partitioning of the upper and lower slope area may be the result of the common feeding habits and suggests a possible competition of these three species. A temporal segregation in the use of the slope area was also observed for sperm whales and Risso's dolphins. Fin whales, and the occasionally encountered common dolphin and long

  20. Short term variability of dissolved lipid classes during summer to autumn transition in the Ligurian sea (NW Mediterranean

    Directory of Open Access Journals (Sweden)

    M. Goutx

    2009-01-01

    Full Text Available Changes in concentration and composition of dissolved lipid classes (Iatroscan TLC/FID were examined at daily to month scale, in relation to the hydrological and biological situation at a central site of the Ligurian sea, NW Mediterranean during the PECHE-DYNAPROC 2 experiment (14 September to 17 October. Dissolved lipid concentrations (TLd and lipid to DOC ratios varied in the range 5.3–48.5 μ g l−1 and 0.01 to 0.08 respectively, along the 0–1000 m water column. The highest TLd concentration values were found in the 0–150 m surface layer coinciding with phytoplankton biomass. Lipid class composition provided valuable information on the origin of DOM, and the changes that occurred during the period investigated. The significant correlations (p<0.01, n=87 between glycolipids from chloroplast membrane (MGDG (38.7±8.5% of TLd, n=166, and various phytoplankton pigments (chlorophyll cs-170, violaxanthin, diadinoxanthin, zeaxanthin, and lutein, suggested that picoeucaryotes were the major source of dissolved lipids. Lipid metabolites (37.6±11.1%, n=166, the second most important compounds in TLd, showed a greater degree of degradation of lipids in this transition period than previously observed earlier in the year. A contribution of lipids to DOM in the mesopelagic zone was observed before the winter mixing: At mid time of the cruise (4–6 October, zooplankton wax esters biomarkers (WE, 5.5–13.6 μg L−1 appeared in the 0–150 m surface layer. WE were observed later and deeper in the mesopelagic layer (6 to 11 October, accompanied by re-increases of hydrocarbons (6–8 October and phospholipids concentrations (12 October in the 400–1000 m depth layer. Zooplankton migration and/or fecal pellets egestion, followed by DOM release from POM, were likely responsible for the appearance of these lipid signatures in the mesopelagic layer, which occurred during the period of low wind (<15 knots

  1. Facies analysis and paleoenvironmental reconstruction of Upper Cretaceous sequences in the eastern Para-Tethys Basin, NW Iran

    Energy Technology Data Exchange (ETDEWEB)

    Omidvar, M.; Safari, A.; Vaziri-Moghaddam, H.; Ghalavand, H.

    2016-07-01

    Upper Cretaceous mixed carbonate-siliciclastic sequences are among the most important targets for hydrocarbon exploration in the Moghan area, located in the eastern Para-Tethys Basin. Despite of their significance, little is known about their facies characteristics and depositional environments. Detailed facies analysis and paleoenvironmental reconstruction of these sequences have been carried out in eight surface sections. Accordingly, four siliciclastic facies, eight carbonate facies and one volcanic facies have been recognized. Detailed facies descriptions and interpretations, together with the results of facies frequency analysis, standard facies models and Upper Cretaceous depositional models of Para-Tethys Basin, have been integrated and a non-rimmed carbonate platform is presented. This platform was affected by siliciclastic influx, in the form of coastal fan delta and submarine fans in the shallow- to deep-marine parts, respectively. This model is interpreted to be shallower in the central and northeastern parts of the Moghan area. Toward the southeast and southwest, this shallow platform turns into deep marine settings along steep slopes without remarkable marginal barriers. (Author)

  2. Cretaceous source rock sedimentation and its relation to transgressive peaks and geodynamic events for the Central Tethys

    Energy Technology Data Exchange (ETDEWEB)

    Flexer, A. (Tel Aviv Univ. (Israel)); Honigstein, A.; Rosenfeld, A. (Geological Survey of Israel, Jerusalem (Israel)); Lipson, S. (Institute of petroleum and energy, Tel Aviv (Israel)); Tarnenbaum, E. (Consultant, Tel Aviv (Israel))

    1993-02-01

    The reconstruction of the Mesozoic continents shows a wide triangle-shaped Tethys (or Neotethys) between Africa and Eurasia. The Arabian Craton comprised the central part of its southern margins. The Cretaceous period started with extension, volcanism, continued by accelerated divergence during Aptian-Turonian and terminated by convergence and folding. The sea level stand, after a major fall at the commencement, is characterized by a steady stepwise rise with some minor retreats. The global oceanic anoxic events correspond to large-extent transgressions and associated with organic rich sedimentation. The accelerated building up of mid-oceanic ridges is possibly connected to a mantle plume, active around 120-80 Ma. Sea level rise and sea floor spreading is felt mainly at these times in the passive southern margins of the central Tethys. The Senonian compressive tectonic regime transforms them into active margins (destruction of oceanic crust, obduction and thrusting); sea level highstands control dysoxic sedimentation. Dysoxic sediments were observed in the Gevaram shales (Tithonian-Hauterivian). Talme Yafe marls (Late Aptian-Albian), Daliyya Formation (latest Cenomanian-Turonian) and the Mount Scopus Group (Santonian-Maastrichtian). The organic matter in the Gevaram shales is mixed marine and terrestrial (2.6% TOC) and in the Daliyya marls mostly marine (2.5% TOC). Both units have source rock possibilities and yield petroleum upon appropriate burial. The Senonian bituminous rocks (oil shales) are rich in marine organic matter (20% TOC) and are excellent source rocks in the Dead Sea area.

  3. Reconstructing the lost eastern Tethys Ocean Basin: Convergence history of the SE Asian margin and marine gateways

    Science.gov (United States)

    Heine, Christian; Müller, R. Dietmar; Gaina, Carmen

    Plate tectonic reconstructions for the late Mesozoic-Cenozoic evolution of the eastern Tethyan Ocean Basin, separating eastern Gondwanaland from Proto-Southeast Asia, are usually based on geological data gathered from the different tectonic blocks accreted to Southeast Asia. However, this approach only provides few constraints on the reconstruction of the eastern Tethys Ocean and the drift path of various terranes. We have used marine magnetic anomalies in the Argo and Gascoyne Abyssal Plains off the Australian Northwest Shelf, jointly with published geological data, to reconstruct the seafloor spreading history and plate tectonic evolution of the eastern Tethys and Proto-Indian Ocean basins for the time between 160 Ma and the present. Based on the assumption of symmetrical seafloor spreading and a hotspot-track-based plate reference frame, we have created a relative and absolute plate motion model and a series of oceanic paleo-age grids that show the evolution of Tethyan mid-ocean ridges and the convergence history along the southeast Asian margin through time. A thermal boundary layer model for oceanic lithosphere is used to compute approximate paleo-depths to oceanic basement to predict the opening and closing of oceanic gateways. The proposed model not only provides improved boundary conditions for paleoclimate reconstructions and modelling of oceanic currents through time, but also for understanding stress changes in the overriding plate and the formation of new accretionary crust along the Southeast Asian margin, driven by changing subduction parameters like hinge rollback and slab dip.

  4. Closure of Tethys and early stages of Himalayan evolution: constraints from the detrital record, Ladakh, India

    Science.gov (United States)

    Jenks, D.; Najman, Y.; Godin, L.; Parrish, R.; Horstwood, M.; Green, O.; Bown, P.; Garzanti, E.; Willems, H.

    2009-04-01

    Closure of Tethys marks initiation of collision between India and Asia, and the start of Himalayan orogenesis. A clear understanding of when this occurred is paramount to understanding the tectonic and denudational processes that have occurred since collision. A number of methods and datasets have been used to constrain the initiation of collision, from faunal mixing at 65 Ma [1] to the timing at which Indian rocks reached UHP depths at 57 Ma [2], to a reduction in northward drift of the Indian plate at 55 Ma [3]. New interpretations have placed collision as late as 38 Ma [4]. The extent of diachroneity is also disputed, varying from slight [5] to substantial [6]. Two approaches are used here to determine collision, 1) the timing of closure of the Tethys Ocean [7], based on stratigraphic succession, 2) first evidence of Asian derived material deposited on the Indian plate [8], using U-Pb ages of detrital zircon to assess provenance. In Ladakh, Indian plate passive margin limestones of the Mid-Late Paleocene Dibling Formation [9] are overlain by the youngest marine facies of the region, the marine siltstones of the Kong Fm. and the fluvio-deltaic facies of the Chulung La Fm. [8]. The age of the Kong and Chulung La formations is disputed, ranging from P5/6 (56 Ma) [10] to P8 (50.5 Ma) [8]. The provenance is also debated, considered either to be eroded from ophiolitic material from the Indian plate [10] or containing detritus from the Trans-Himalayan arc of the Asian plate [8,11]. We applied biostratigraphy, and U-Pb dating on detrital zircon, to samples from the Kong and Chulung La Formations to define depositional age and provenance. Biostratigraphy identified Asselines A. placentula grande and A. pomeroli, from the SBZ 10 (50.5 to 52.5 Ma) and SBZ 9 (53 Ma) zones respectively, thereby defining a minimum age of collision at 50.5 Ma, based on cessation of marine facies. However, the possibility that these fossils are reworked will be discussed. U-Pb dating of

  5. The Jurassic of Denmark and Greenland: Shallow marine syn-rift sedimentation: Middle Jurassic Pelion Formation, Jameson Land, East Greenland

    Directory of Open Access Journals (Sweden)

    Engkilde, Michael

    2003-10-01

    Full Text Available The Middle Jurassic Pelion Formation – Fossilbjerget Formation couplet of Jameson Land, East Greenland, is a well-exposed example of the Middle Jurassic inshore–offshore successions characteristicof the rifted seaways in the Northwest European – North Atlantic region. Early Jurassic deposition took place under relatively quiet tectonic conditions following Late Permian – earliest Triassic and Early Triassic rift phases and the Lower Jurassic stratal package shows an overall layer-cake geometry. A long-term extensional phase was initiated in Middle Jurassic (Late Bajocian time, culminated in the Late Jurassic (Kimmeridgian–Volgian, and petered out in the earliest Cretaceous (Valanginian. The Upper Bajocian – Middle Callovian early-rift succession comprises shallow marine sandstones of the Pelion Formation and correlative offshore siltstones of theFossilbjerget Formation. Deposition was initiated by southwards progradation of shallow marine sands of the Pelion Formation in the Late Bajocian followed by major backstepping in Bathonian–Callovian times and drowning of the sandy depositional system in the Middle–Late Callovian. Six facies associations are recognised in the Pelion–Fossilbjerget couplet, representing estuarine, shoreface, offshore transition zone and offshore environments. The north–southtrendingaxis of the Jameson Land Basin had a low inclination, and deposition was sensitive to even small changes in relative sea level which caused the shorelines to advance or retreat over tens to several hundreds of kilometres. Eight composite sequences, termed P1–P8, are recognised and are subdivided into a total of 28 depositional sequences. The duration of the two orders of sequences was about 1–2 Ma and 360,000 years, respectively. The Upper Bajocian P1–2 sequencesinclude the most basinally positioned shallow marine sandstones, deposited during major sealevel lowstands. The lowstands were terminated by significant marine

  6. Rock mechanics related to Jurassic underburden at Valdemar oil field

    DEFF Research Database (Denmark)

    Foged, Niels

    1999-01-01

    .It has been initiated as a feasibility study of the North Jens-1 core 12 taken in the top Jurassic clay shale as a test specimens for integrated petrological, mineralogical and rock mechanical studies. Following topics are studied:(1) Pore pressure generation due to conversion of organic matter...... and deformation properties of the clay shale using the actual core material or outcrop equivalents.(3) Flushing mechanisms for oil and gas from source rocks due to possibly very high pore water pressure creating unstable conditions in deeply burried sedimentsThere seems to be a need for integrating the knowledge...... in a number of geosciences to the benefit of common understanding of important reservoir mechanisms. Rock mechanics and geotechnical modelling might be key points for this understanding of reservoir geology and these may constitute a platform for future research in the maturing and migration from the Jurassic...

  7. A new carnivorous dinosaur from the Late Jurassic Solnhofen archipelago.

    Science.gov (United States)

    Göhlich, Ursula B; Chiappe, Luis M

    2006-03-16

    Small Late Jurassic theropod dinosaurs are rare worldwide. In Europe these carnivorous dinosaurs are represented primarily by only two skeletons of Compsognathus, neither of which is well preserved. Here we describe a small new theropod dinosaur from the Late Jurassic period of Schamhaupten in southern Germany. Being exquisitely preserved and complete from the snout to the distal third of the tail, the new fossil is the best-preserved predatory, non-avian dinosaur in Europe. It possesses a suite of characters that support its identification as a basal coelurosaur. A cladistic analysis indicates that the new taxon is closer to maniraptorans than to tyrannosauroids, grouping it with taxa often considered to be compsognathids. Large portions of integument are preserved along its tail. The absence of feathers or feather-like structures in a fossil phylogenetically nested within feathered theropods indicates that the evolution of these integumentary structures might be more complex than previously thought.

  8. A basal tyrannosauroid dinosaur from the Late Jurassic of China.

    Science.gov (United States)

    Xu, Xing; Clark, James M; Forster, Catherine A; Norell, Mark A; Erickson, Gregory M; Eberth, David A; Jia, Chengkai; Zhao, Qi

    2006-02-01

    The tyrannosauroid fossil record is mainly restricted to Cretaceous sediments of Laurasia, although some very fragmentary Jurassic specimens have been referred to this group. Here we report a new basal tyrannosauroid, Guanlong wucaii gen. et sp. nov., from the lower Upper Jurassic of the Junggar Basin, northwestern China. G. wucaii is the oldest known tyrannosauroid and shows several unexpectedly primitive pelvic features. Nevertheless, the limbs of G. wucaii share several features with derived coelurosaurs, and it possesses features shared by other coelurosaurian clades. This unusual combination of character states provides an insight into the poorly known early radiation of the Coelurosauria. Notably, the presumed predatory Guanlong has a large, fragile and highly pneumatic cranial crest that is among the most elaborate known in any non-avian dinosaur and could be comparable to some classical exaggerated ornamental traits among vertebrates.

  9. A mysterious giant ichthyosaur from the lowermost Jurassic of Wales

    Directory of Open Access Journals (Sweden)

    Jeremy E. Martin

    2015-12-01

    Full Text Available Ichthyosaurs rapidly diversified and colonised a wide range of ecological niches during the Early and Middle Triassic period, but experienced a major decline in diversity near the end of the Triassic. Timing and causes of this demise and the subsequent rapid radiation of the diverse, but less disparate, parvipelvian ichthyosaurs are still unknown, notably because of inadequate sampling in strata of latest Triassic age. Here, we describe an exceptionally large radius from Lower Jurassic deposits at Penarth near Cardiff, south Wales (UK the morphology of which places it within the giant Triassic shastasaurids. A tentative total body size estimate, based on a regression analysis of various complete ichthyosaur skeletons, yields a value of 12–15 m. The specimen is substantially younger than any previously reported last known occurrences of shastasaurids and implies a Lazarus range in the lowermost Jurassic for this ichthyosaur morphotype.

  10. Rock mechanics related to Jurassic underburden at Valdemar oil field

    DEFF Research Database (Denmark)

    Foged, Niels

    1999-01-01

    The presented study is a part of the Danish Energy Research project PRIORITY - Imroved Oil Recovery and Productivity from Lower Cretaceous Carbonates.It considers a multi-disciplinary study of the Jurassic shale underlying the Valdemar structure and gives a status of the on-going research work.......It has been initiated as a feasibility study of the North Jens-1 core 12 taken in the top Jurassic clay shale as a test specimens for integrated petrological, mineralogical and rock mechanical studies. Following topics are studied:(1) Pore pressure generation due to conversion of organic matter...... and deformation properties of the clay shale using the actual core material or outcrop equivalents.(3) Flushing mechanisms for oil and gas from source rocks due to possibly very high pore water pressure creating unstable conditions in deeply burried sedimentsThere seems to be a need for integrating the knowledge...

  11. The palaeogeography of Sundaland and Wallacea since the Late Jurassic

    OpenAIRE

    Robert Hall

    2013-01-01

    The continental core of Southeast (SE) Asia, Sundaland, was assembled from Gondwana fragments by the Early Mesozoic. Continental blocks rifted from Australia in the Jurassic [South West (SW) Borneo, East Java-West Sulawesi-Sumba], and the Woyla intraoceanic arc of Sumatra, were added to Sundaland in the Cretaceous. These fragments probably included emergent areas and could have carried a terrestrial flora and fauna. Sarawak, the offshore Luconia-Dangerous Grounds areas, and Palawan include As...

  12. MIDDLE TO LATE JURASSIC BIOFACIES OF SAUDI ARABIA

    Directory of Open Access Journals (Sweden)

    GERAINT W. HUGHES

    2004-03-01

    Full Text Available Saudi Arabian Jurassic carbonate hydrocarbon reservoirs were first examined stratigraphically using microfauna. Current microfaunal studies concentrate on the identification and constraint of palaeoenvironmental variations and determination of high-resolution depositional cyclicity of the reservoir carbonates. It is apparent that the environmental sensitivity of benthonic foraminifera provides a potentially valuable technique for the determining subtle variations in the depositional environment and also providing a proxy for sea-level fluctuations.

  13. Carbon cycle history through the Middle Jurassic of Hungary

    Science.gov (United States)

    Price, Gregory; Fozy, Istvan; Galacz, Andras

    2016-04-01

    A carbonate carbon isotope curve from the Aalenian-Bathonian interval is presented from the Obanya valley, of the Mecsek Mountains, Hungary. This interval is less well constrained and studied that other Jurassic time slices. The Obanya valley lies in the eastern part of the Mecsek Mountains, between Obanya and Kisujbanya and provides excellent exposures of a near continuous Aalenian to Lower Cretaceous sequence. It is not strongly affected by tectonics, as compared to other sections of eastern Mecsek of the same age. In parts, a rich fossil assemblage has been collected; the Bathonian ammonites are especially valuable as this locality. The pelagic Middle Jurassic is represented by thin-bedded limestones (the Obanya Limestone) and is overlain by Upper Jurassic siliceous limestones and radiolarites (the Fonyaszo Limestone). The new data indicates a series of positive anomalies within the late Aalenian and early-middle Bajocian. These data are comparable with carbonate carbon isotope recorded from other Tethyan margin sediments. Our integrated biostratigraphy and carbon isotope stratigraphy enables us to improve stratigraphic correlation and age determination of the examined strata.

  14. Archosaur evolution during the Jurassic: a southern perspective

    Directory of Open Access Journals (Sweden)

    Oliver W. M. Rauhut

    2008-12-01

    Full Text Available The fossil record of archosaurs - crocodylomorphs, pterosaurs and dinosaurs - from the Jurassic of the Southern Hemisphere is critically reviewed, and its evolutionary implications are evaluated. Although several important faunas and also isolated finds are known from Gondwana, the record in total is still very patchy, and any evolutionary scenario based on this record should be seen as tentative. Compared to the Northern Hemisphere, southern archosaurs are much more poorly known, which is especially true for terrestrial crocodiles and pterosaurs. Marine crocodiles are rather well represented in south-western South America, whereas the report of terrestrial archosaurs is currently best for Africa. However, in South America, important and especially promising archosaur faunas are known from the Callovian Cañadón Asfalto and the (?Tithonian Cañadón Calcáreo formations of Chubut province, Argentina. Early and Middle Jurassic Gondwanan archosaurs demonstrate that the faunas of that period still had a generally Pangean distribution, whereas first indications of differential archosaur evolution in the Northern and Southern Hemispheres are evident in Late Jurassic Gondwanan faunas.

  15. Mass-transport deposit and mélange formation in the Ligurian accretionary complex (NW-Italy) via mutual interactions of tectonic, sedimentary and diapiric processes

    Science.gov (United States)

    Festa, A.; Codegone, G.; Dilek, Y.; Ogata, K.; Pini, G.

    2011-12-01

    Slope instability and material removal from the overriding plate are common in frontal wedges of subduction-accretionary complexes, form mass-transport deposits (MTDs), and play an important role in controlling the internal dynamics of a critical taper Coulomb wedge and its slope instability. We present different examples of ancient MTDs emplaced during the late Cretaceous-Miocene evolution of the External Ligurian accretionary wedge and the related wedge-top basins (Epiligurian Units Auct.) in the NW-Apennines, Italy. These MTDs consist of sedimentary mélanges or olistostromes and display heterogeneous deformation controlled by the degree of sediment consolidation and the velocity of gravitational processes (Festa et al., 2010 IGR; Pini et al., 2011 Springer Book). Decimeter- to meter-thick shear zones associated with localized visco-plastic deformation and highly disturbed rounded and/or subangular blocks randomly distributed in a brecciated matrix form the two end-members of structures. Crosscutting relationships between MTDs and coherent successions, tectonic mélanges - broken formation and injection bodies (shaly-dykes and/or diapirs) allow us to document their time-progressive development, the correlation with tectonic and diapiric processes, and the material redistribution forming polygenic mélanges in the frontal part of the External Ligurian accretionary wedge. Out-of-sequence "megathrust" and strike-slip faulting, fluid overpressure, presence of low-permeable layers and methane-rich fluid circulation in the sedimentary column were the main factors that controlled the emplacement of various MTDs. In all the examples described, mass-transport was closely associated and had mutual interactions with tectonic and diapiric processes (Festa, 2011 GSA Sp Publ). Tectonics played the most prominent role (directly and indirectly), whereas fluid flow and overpressure strongly controlled the mechanical behavior of sediments and facilitated the emplacement of

  16. Will the French Riviera disappear? Ancient and present day submarine landslides along the north-western Ligurian Margin (NW Mediterranean) under the microscope

    Science.gov (United States)

    Hassoun, V.; Migeon, S.; Larroque, C.; Cattaneo, A.; Mercier De Lepinay, B. F.

    2011-12-01

    The integration between seismic-reflection and bathymetric data highlighted more than one thousand and three hundred ancient and recent scars and Mass Transport Deposits (MTDs) related to submarine failures along the whole northern margin of the Ligurian Basin. Several types of failures are pointed out along the margin according to their morphology, distribution and origin: (1) Numerous superficial landslides affected largely the inner walls of canyons and the upper continental slope at the vicinity of the main mountain-supplied rivers where the sedimentation rates are the strongest and thus contribute to the progressive stressing of the slope. This type of scars is mainly observed in the western margin where the thickness of plio-quaternary sediment is the lowest. (2) Large-scale scars and successive MTDs affecting the upper part of interfluves in the Gulf of Genova (Finale Slide and Portofino Slide) could have been triggered by earthquakes as well as by indirect effects of the last sea level drop. (3) At the north-eastern margin, offshore of Imperia, there is a large promontory bounded by a network of N60°E faults on its southern side and characterized by the presence of many landslides of variable sizes associated to unconformities could correspond to the different phases of recent, and perhaps present-day, uplift of the Imperia Promontory. (4) Deep scars along the base of the continental slope and possibly related to the seismic activity of a neighbouring fault, as the Cirque Marcel located near the Marcel Fault which appears on the seafloor as a 10-km long scarp trending N60°E. (5) In the western basin, near of the foot of the continental slope, the bathymetry is mark by a convexity which corresponds on the seismic data to the superposition of several thick MTDs. (6) In the deep basin and the eastern part of the Ligurian Basin, the thick plio-quaternary deposits are constitute by an alternation between continuous reflectors corresponding to hemipelagic

  17. The Jurassic of Denmark and Greenland: key elements in the reconstruction of the North Atlantic Jurassic rift system

    Directory of Open Access Journals (Sweden)

    Surlyk, Finn

    2003-10-01

    Full Text Available The Jurassic succession of Denmark is largely confined to the subsurface with the exception of exposures on the island of Bornholm in the Baltic Sea. In East Greenland, in contrast, the Jurassic is extensively exposed. Comparison of basin evolution in the two regions, which now occur on two separate plates, thus relies on highly different datasets. It is possible nevertheless to construct an integrated picture allowing testing of hypotheses concerning basin evolution, regional uplift, onset and climax of rifting, relative versus eustatic sea-level changes and sequence stratigraphic subdivision and correlation. On a smaller scale, it is possible to compare the signatures of sequence stratigraphic surfaces as seen on well logs, in cores and at outcrop and of sequences recognised and defined on the basis of very different data types. Breakdown of the successions into tectonostratigraphic megasequences highlights the high degree of similarity in overall basin evolution and tectonic style. An important difference, however, lies in the timing. Major events such as late Early - Middle Jurassic uplift, followed by onset of rifting, basin reorganisation and rift climax were delayed in East Greenland relative to the Danish region. This has important implications both for regional reconstructions of the rift system and for the understanding and testing of classical sequence stratigraphic concepts involving eustatic versus tectonic controls of basin evolution and stratigraphy.

  18. Temporal patterns in disparity and diversity of the Jurassic ammonoids of southern Germany

    Directory of Open Access Journals (Sweden)

    M. S. Simon

    2011-02-01

    Full Text Available A morphometric analysis of the characteristic whorl cross-sections of 1,200 Jurassic ammonoid species from southern Germany enabled us to characterise their morphospace. The successive Jurassic ammonoid faunas of southern Germany show characteristic patterns in morphospace occupation. While Early and Middle Jurassic ammonoids occupy limited areas of the morphospace range, the Late Jurassic ammonoids cover the entire spectrum. The ammonoids are characterised by an overall increase of both taxonomic diversity and morphological disparity in the course of the Jurassic. Strong fluctuations occur until the middle Late Jurassic, followed by a diversity decrease in the early Kimmeridgian and a disparity reduction in the early Tithonian. While diversity and disparity show similar progression during most of the Early Jurassic, they diverge subsequently and show only poor correlation until the end of the Jurassic. Particularly in the Middle Jurassic diversity and sea level changes correlate strongly. Neither temporal patterns in diversity nor disparity support the hypothesis of a mass extinction event in the early Toarcian. Significant changes in diversity and disparity in the early Callovian support a putative migration event of Boreal ammonoids into the Tethyan realm. doi:10.1002/mmng.201000016

  19. Geochemistry evidence for depositional settings and provenance of Jurassic argillaceous rocks of Jiyuan Basin, North China

    Indian Academy of Sciences (India)

    Yao Meng; Deshun Zheng; Minglong Li

    2017-02-01

    This paper aims to discuss the depositional settings and provenances for the Jurassic in Jiyuan basin, North China, based on the rare earth element (REE) and trace element features of 16 Jurassic argillaceous rock samples from the Anyao, Yangshuzhuang and Ma’ao Formations, respectively. Generally, geochemical analysis results show that chondrite-normalised REE distribution patterns of all the three formations are characterised by light-REE (LREE) enrichment, moderately negative Eu anomalies, slightly negative Ce anomalies, and strong fractionation between LREE and heavy-REE (HREE). Trace element proxies V/(V+Ni), Ceanom index, Ce/La, Sr/Ba, and Sr/Cu indicate a weak oxidation–reduction environment, progressively decreasing reducibility and water depth from the bottom up during Jurassic in Jiyuan basin. Palaeoclimate varied from humid in the Early Jurassic to arid in the Middle Jurassic, corresponding with the variations of palaeoredox and palaeosalinity. The provenances of Jurassic rocks in Jiyuan basin are mainly from felsic sources related to active continental margin and continental island arc. The Early–Middle Jurassic (Anyao and Yangshuzhuang Formations) provenances are mainly derived from North Qinling and partially from the eroded recycled felsic sedimentary covers of Taihang Mountain. In the late stage of Middle Jurassic (Ma’ao Formation), Taihang Mountain has been the primary source to Jiyuan basin. We conclude that the Jurassic rocks of Jiyuan basin reveal the progressive uplift and denudation processes of the Taihang Mountain.

  20. Physical and dynamical characteristics of a 300 m-deep anticyclonic eddy in the Ligurian Sea (Northwest Mediterranean Sea): Evidence from a multi-platform sampling strategy

    Science.gov (United States)

    Borrione, Ines; Falchetti, Silvia; Alvarez, Alberto

    2016-10-01

    We describe the physical and dynamical characteristics of a mesoscale anticyclonic eddy observed in August 2013 over the shelf-break region of the northeastern sector of the Ligurian Sea, between the northeastern edge of the Northern Current (NC) and the coast. Results derive from a dense dataset of temperature, salinity and current measurements obtained from a multi-platform sampling strategy as well as from a diagnostic simulation with the Regional Ocean Modeling System (ROMS) at a horizontal resolution of 1.8 km. Model results are obtained from a strong nudging to observations and, as they are physically balanced, they allow a three-dimensional diagnosis of the dynamics and physical characteristics of the eddy. The eddy is centered around 9.5°E, 43.94°N, about 20 km from the coast, and has a radius of 16 km. It is characterized by low-density waters and penetrates the thermocline down to at least 300 m reflecting the main features of the NC. Horizontal velocities near the surface are around 0.4 m s-1, while at 150 m are still significantly high and close to 0.2 m s-1. Vertical velocities were estimated from model results; absolute values are below 4 m day-1 until depths shallower than 150 m and increase with depth to 15 m day-1. The eddy's presence inverts the northwestwards flow traditionally portrayed in the region determining a southeastwards coastal circulation that replenishes coastal waters with those originating from the NC. We discuss several possible eddy formation mechanisms and suggest that its formation depends on the directionality of the NC when it enters the Ligurian Sea, as a result of the adjustment of the shear and orbital components of the current's relative vorticity.

  1. Tectonic Inversion Along the Algerian and Ligurian Margins: On the Insight Provided By Latest Seismic Processing Techniques Applied to Recent and Vintage 2D Offshore Multichannel Seismic Data

    Science.gov (United States)

    Schenini, L.; Beslier, M. O.; Sage, F.; Badji, R.; Galibert, P. Y.; Lepretre, A.; Dessa, J. X.; Aidi, C.; Watremez, L.

    2014-12-01

    Recent studies on the Algerian and the North-Ligurian margins in the Western Mediterranean have evidenced inversion-related superficial structures, such as folds and asymmetric sedimentary perched basins whose geometry hints at deep compressive structures dipping towards the continent. Deep seismic imaging of these margins is difficult due to steep slope and superficial multiples, and, in the Mediterranean context, to the highly diffractive Messinian evaporitic series in the basin. During the Algerian-French SPIRAL survey (2009, R/V Atalante), 2D marine multi-channel seismic (MCS) reflection data were collected along the Algerian Margin using a 4.5 km, 360 channel digital streamer and a 3040 cu. in. air-gun array. An advanced processing workflow has been laid out using Geocluster CGG software, which includes noise attenuation, 2D SRME multiple attenuation, surface consistent deconvolution, Kirchhoff pre-stack time migration. This processing produces satisfactory seismic images of the whole sedimentary cover, and of southward dipping reflectors in the acoustic basement along the central part of the margin offshore Great Kabylia, that are interpreted as inversion-related blind thrusts as part of flat-ramp systems. We applied this successful processing workflow to old 2D marine MCS data acquired on the North-Ligurian Margin (Malis survey, 1995, R/V Le Nadir), using a 2.5 km, 96 channel streamer and a 1140 cu. in. air-gun array. Particular attention was paid to multiple attenuation in adapting our workflow. The resulting reprocessed seismic images, interpreted with a coincident velocity model obtained by wide-angle data tomography, provide (1) enhanced imaging of the sedimentary cover down to the top of the acoustic basement, including the base of the Messinian evaporites and the sub-salt Miocene series, which appear to be tectonized as far as in the mid-basin, and (2) new evidence of deep crustal structures in the margin which the initial processing had failed to

  2. Porphyry copper assessment of the Tethys region of western and southern Asia: Chapter V in Global mineral resource assessment

    Science.gov (United States)

    Zürcher, Lukas; Bookstrom, Arthur A.; Hammarstrom, Jane M.; Mars, John C.; Ludington, Stephen; Zientek, Michael L.; Dunlap, Pamela; Wallis, John C.; Drew, Lawrence J.; Sutphin, David M.; Berger, Byron R.; Herrington, Richard J.; Billa, Mario; Kuşcu, Ilkay; Moon, Charles J.; Richards, Jeremy P.; Zientek, Michael L.; Hammarstrom, Jane M.; Johnson, Kathleen M.

    2015-11-18

    A probabilistic mineral resource assessment of undiscovered resources in porphyry copper deposits in the Tethys region of western and southern Asia was carried out as part of a global mineral resource assessment led by the U.S. Geological Survey (USGS). The purpose of the study was to delineate geographic areas as permissive tracts for the occurrence of porphyry copper deposits at a scale of 1:1,000,000 and to provide probabilistic estimates of amounts of copper likely to be contained in undiscovered porphyry copper deposits in those tracts. The team did the assessment using the USGS three-part form of mineral resource assessment, which is based on (1) mineral deposit and grade-tonnage models constructed from known deposits as analogs for undiscovered deposits, (2) delineation of permissive tracts based on geoscientific information, and (3) estimation of numbers of undiscovered deposits.

  3. The fragment of Paleo-Tethys ophiolite from central Qiangtang, Tibet: Geochemical evidence of metabasites in Guoganjianian

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    N-MORB-type metabasites are discovered in the Guoganjianian area, central Qiangtang, Tibet, which are mainly metagabbro with cumulate structure and metabasalt. The rocks are distributed nearly from west to east unconformably underlying the Wanghuling Group of upper Triassic. On the basis of geochemical analysis, we find that the content of SiO2 is 43.03%―53.42%, and TiO2 1%―2.67%, Al2O3 16.75%―21.52%, CaO 7.03%―11.13%, K2O 0.05%―0.38%; the REE pattern is slight depletion or flat, and the trace spider diagram is like that of N-MORB, so we consider that the metabasite was formed under the setting of mid-ocean ridge or adult back-arc basin, and it is the fragment of Paleo-Tethys ophiolite.

  4. Search for and limits on plume activity on Mimas, Tethys, and Dione with the Cassini Visual Infrared Mapping Spectrometer (VIMS)

    Science.gov (United States)

    Buratti, B.J.; Faulk, S.P.; Mosher, J.; Baines, K.H.; Brown, R.H.; Clark, R.N.; Nicholson, P.D.

    2011-01-01

    Cassini Visual Infrared Mapping Spectrometer (VIMS) observations of Mimas, Tethys, and Dione obtained during the nominal and extended missions at large solar phase angles were analyzed to search for plume activity. No forward scattered peaks in the solar phase curves of these satellites were detected. The upper limit on water vapor production for Mimas and Tethys is one order of magnitude less than the production for Enceladus. For Dione, the upper limit is two orders of magnitude less, suggesting this world is as inert as Rhea (Pitman, K.M., Buratti, B.J., Mosher, J.A., Bauer, J.M., Momary, T., Brown, R.H., Nicholson, P.D., Hedman, M.M. [2008]. Astrophys. J. Lett. 680, L65-L68). Although the plumes are best seen at ???2.0. ??m, Imaging Science Subsystem (ISS) Narrow Angle Camera images obtained at the same time as the VIMS data were also inspected for these features. None of the Cassini ISS images shows evidence for plumes. The absence of evidence for any Enceladus-like plumes on the medium-sized saturnian satellites cannot absolutely rule out current geologic activity. The activity may below our threshold of detection, or it may be occurring but not captured on the handful of observations at large solar phase angles obtained for each moon. Many VIMS and ISS images of Enceladus at large solar phase angles, for example, do not contain plumes, as the active "tiger stripes" in the south pole region are pointed away from the spacecraft at these times. The 7-year Cassini Solstice Mission is scheduled to gather additional measurements at large solar phase angles that are capable of revealing activity on the saturnian moons. ?? 2011 Elsevier Inc.

  5. An Extensible, Modular Architecture Coupling HydroShare and Tethys Platform to Deploy Water Science Web Apps

    Science.gov (United States)

    Nelson, J.; Ames, D. P.; Jones, N.; Tarboton, D. G.; Li, Z.; Qiao, X.; Crawley, S.

    2016-12-01

    As water resources data continue to move to the web in the form of well-defined, open access, machine readable web services provided by government, academic, and private institutions, there is increased opportunity to move additional parts of the water science workflow to the web (e.g. analysis, modeling, decision support, and collaboration.) Creating such web-based functionality can be extremely time-consuming and resource-intensive and can lead the erstwhile water scientist down a veritable cyberinfrastructure rabbit hole, through an unintended tunnel of transformation to become a Cyber-Wonderland software engineer. We posit that such transformations were never the intention of the research programs that fund earth science cyberinfrastructure, nor is it in the best interest of water researchers to spend exorbitant effort developing and deploying such technologies. This presentation will introduce a relatively simple and ready-to-use water science web app environment funded by the National Science Foundation that couples the new HydroShare data publishing system with the Tethys Platform web app development toolkit. The coupled system has already been shown to greatly lower the barrier to deploying of web based visualization and analysis tools for the CUAHSI Water Data Center and for the National Weather Service's National Water Model. The design and implementation of the developed web app architecture will be presented together key examples of existing apps created using this system. In each of the cases presented, water resources students with basic programming skills were able to develop and deploy highly functional web apps in a relatively short period of time (days to weeks) - allowing the focus to remain on water science rather on cyberinfrastructure. This presentation is accompanied by an open invitation for new collaborations that use the HydroShare-Tethys web app environment.

  6. Maastrichtian-aged lithostratigraphic patterns in the European tethys: Implications for sea level change and end-Cretaceous extinction patterns

    Energy Technology Data Exchange (ETDEWEB)

    Ward, P.; Macleod, K.G. (Univ. of Washington, Seattle, WA (United States). Dept. of Geological Sciences)

    1992-01-01

    Thirteen Maastrichtian-aged stratigraphic sections from a variety of sites spanning the ancient Tethys ocean in Western and Eastern Europe and Northern Africa have been measured in this study. The similarity in lithologies between even geographically separated localities allows refined lithostratigraphic correlation; individual members first defined from Bay of Biscay sections can now be recognized through all sections. The sections are found in the Bay of Biscay and Basque region of France and Spain (Sopelana, Zumaya, Hendaye, Bidart, Tercis, Pamplona;) southern Spain (Caravaca, Agost); northern Africa (El Kef); and Eastern Europe (Georgia). All of the sections are dominated by limestones in the Lower Maastrichtian, and marls or limestone-marl rhythmites in the Upper Maastrichtian. A conspicuous, massive limestone, usually 10 to 15 m thick, is found in all sections at the top of the Lower Maastrichtian; it is invariably overlain by a thicker unit composed entirely of marl. The thick limestone contains the last body fossils of the genus Inoceramus, and occurs just beneath the first occurrence of foraminifera diagnostic of the Abathomphalus mayaroensis Zone of Late Maastrichtian age. The dramatic shift in lithology lies at or just beneath the boundary between the Lower and Upper Maastrichtian, and may have been caused by one of the most rapid and profound sea level changes of the Cretaceous Period. The sea-level change may be a causal factor in the mid-Maastrichtian extinction which affected the Inoceramidae and other mollusks, such as the rudistid bivalves and ammonites, and certainly is one of the dominant factors in forming the sequence of lithologies found in the Maastrichtian Stage of Tethys.

  7. Nd isotope constraints on ocean circulation, paleoclimate, and continental drainage during the Jurassic breakup of Pangea

    DEFF Research Database (Denmark)

    Dera, Guillaume; Prunier, Jonathan; Smith, Paul L.

    2015-01-01

    -Panthalassan arcs, new oceanic circulation patterns, and changes in heat and humidity transports affecting continental weathering. Few studies, however, have attempted to unravel the global interactions linking these processes over the long-term. In this paper, we address this question by documenting the global...... unradiogenic Arctic waters occurred in the NW Tethys in the Callovian-Early Oxfordian. All these results show that changes in surface oceanic circulation resulting from the Pangean breakup could have regionally impacted the evolution of seawater temperatures in the NW Tethys....

  8. Newly discovered Jurassic skarnfields in the Ecuadorian Andes

    Science.gov (United States)

    Litherland, M.; Fortey, N. J.; Beddoe-Stephens, B.

    1992-08-01

    A series of calcic magnetite skarn klippen in the north of the Cordillera Real are interpreted as erosional relics of a great skarn sheet, over 150 km long, formed by thrusting of island-arc type sediments and volcanics over the Jurassic Azafran batholith during an accretion event. The skarns are contrasted petrographically and compositionally with those of the Nambija field in the south of the Cordillera, which probably relates to the same chain of batholiths. However, the Nambija skarns are autochthonous and rich in gold, with Au:Ag ratios in the region of 20:1, whereas those to the north are allochthonous and relatively barren.

  9. An arboreal docodont from the Jurassic and mammaliaform ecological diversification

    Science.gov (United States)

    Meng, Qing-Jin; Ji, Qiang; Zhang, Yu-Guang; Liu, Di; Grossnickle, David M.; Luo, Zhe-Xi

    2015-02-01

    A new docodontan mammaliaform from the Middle Jurassic of China has skeletal features for climbing and dental characters indicative of an omnivorous diet that included plant sap. This fossil expands the range of known locomotor adaptations in docodontans to include climbing, in addition to digging and swimming. It further shows that some docodontans had a diet with a substantial herbivorous component, distinctive from the faunivorous diets previously reported in other members of this clade. This reveals a greater ecological diversity in an early mammaliaform clade at a more fundamental taxonomic level not only between major clades as previously thought.

  10. Tectonic forcing of early to middle jurassic seawater Sr/Ca

    DEFF Research Database (Denmark)

    Ullmann, Clemens Vinzenz; Hesselbo, Stephen P.; Korte, Christoph

    2013-01-01

    The Jurassic Period (ca. 201–145 Ma) is marked by fundamental reorganizations of paleogeography, paleoceanography, ecosystems, and the progressive shift from aragonite to calcite as the favored marine biogenic carbonate polymorph. Sr/Ca ratios of well-preserved Jurassic oysters and belemnites from...

  11. A New Theropod Dinosaur from the Middle Jurassic of Lufeng, Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-chun; Philip J.CURRIE; DONG Zhiming; PAN Shigang; WANG Tao

    2009-01-01

    A new theropod dinosaur,Shidaisaurusjinae gen.et sp.nov.,has been described on the basis of an incomplete skeleton.The specimen was found near the base of the Upper Lufeng Formation(early Middle Jurassic)in Yunnan,China.It is the first theropod dinosaur from the Middle Jurassic of Yunnan.Shidaisaurus jinae is distinguishable from other Jurassic theropods by certain features from the braincase,axis,and pelvic girdle.The absence of any pleurocoels in the axis or in any anterior dorsal vertebrae suggests that the new Lufeng theropod is relatively primitive and more plesiomorphic than most of the Middle to Late Jurassic theropods from China.Most Chinese taxa of Jurassic theropod dinosaurs have not been well described;a further detailed study will be necessary for us to determine their phylogenetic relationships with Shidaisaurus jinae.

  12. A tectonic model reconciling evidence for the collisions between India, Eurasia and intra-oceanic arcs of the central-eastern Tethys

    Digital Repository Service at National Institute of Oceanography (India)

    Gibbons, A.D.; Zahirovic, S.; Müller, R.D.; Whittaker, J.M.; Yatheesh, V.

    that formed on the southern Eurasian margin. Our model is regionally-constrained and self-consistent, incorporating geophysical data from abyssal plains offshore West Australia and East Antarctica, including Jurassic age data from offshore Northwest Australia...

  13. Transgression regression event element geochemistry records of southwestern Fujian in Late Triassic-Middle Jurassic

    Institute of Scientific and Technical Information of China (English)

    许中杰; 程日辉; 张莉; 王嘹亮

    2013-01-01

    Southwest Fujian area has experienced a large-scale transgression regression cycle in Late Triassic-Middle Jurassic and the maximum transgression has taken place in Early Jurassic. The migration and enrichment of geochemical element in the continuous fine-grained sediments in the basin recorded the paleosalinity and the paleodepth. The changes of paleosalinity and paleodepth indicate the sea(lake) level relative change in every period of Late Triassic-Middle Jurassic in southwestern Fujian. The relative change curve of sea(lake) level in southwestern Fujian is established based on the m value(m=100×w(MgO)/w(Al2 O3)) and the ratios of w(B)/w(Ga), w(Sr)/w(Ba) and w(Ca)/w(Mg). The curve indicates that level I sea-level relative change in southwestern Fujian is composed of the transgression in Late Triassic-Early Jurassic and the regression in the late period of Early Jurassic-Middle Jurassic. The level III sea-level relative change is frequent, which is composed by the lake level descent lake level rise lake level descent of Wenbin Shan formation in Late Triassic, the regression transgression regression of Lishan formation in Early Jurassic and the lake level rise lake level descent-lake level rise lake level descent of Zhangping formation in Middle Jurassic. The transgression regression cycle in southwestern Fujian is significantly controlled by the sea-level change in the north of South China Sea. The relative change curve trends of the level I sea-level in the north of South China Sea and the one in southwestern Fujian are the same. The maximum transgressions both occur in Early Jurassic. The level III sea-level curve reflects the fluctuation of a transgression and two regressions in the early period of Early Jurassic.

  14. Amphibious flies and paedomorphism in the Jurassic period.

    Science.gov (United States)

    Huang, Diying; Nel, André; Cai, Chenyang; Lin, Qibin; Engel, Michael S

    2013-03-01

    The species of the Strashilidae (strashilids) have been the most perplexing of fossil insects from the Jurassic period of Russia and China. They have been widely considered to be ectoparasites of pterosaurs or feathered dinosaurs, based on the putative presence of piercing and sucking mouthparts and hind tibio-basitarsal pincers purportedly used to fix onto the host's hairs or feathers. Both the supposed host and parasite occur in the Daohugou beds from the Middle Jurassic epoch of China (approximately 165 million years ago). Here we analyse the morphology of strashilids from the Daohugou beds, and reach markedly different conclusions; namely that strashilids are highly specialized flies (Diptera) bearing large membranous wings, with substantial sexual dimorphism of the hind legs and abdominal extensions. The idea that they belong to an extinct order is unsupported, and the lineage can be placed within the true flies. In terms of major morphological and inferred behavioural features, strashilids resemble the recent (extant) and relict members of the aquatic fly family Nymphomyiidae. Their ontogeny are distinguished by the persistence in adult males of larval abdominal respiratory gills, representing a unique case of paedomorphism among endopterygote insects. Adult strashilids were probably aquatic or amphibious, shedding their wings after emergence and mating in the water.

  15. Triassic-Jurassic pteridosperms of Australasia: speciation, diversity and decline

    Energy Technology Data Exchange (ETDEWEB)

    Pattemore, G. A.; Rigby, J. F.; Playford, G.

    2015-07-01

    Pteridosperms are preserved abundantly in the Gondwanan Triassic, with many species exhibiting consider- able morphological variation that has been attributed to a hybridization model of speciation. This is an improbable explanation given that hybridization is very rare in gymnosperms. Allopatric speciation resulting from geographic and climatic provincialism is a more likely explanation for the morphological diversity which is well represented in Anisian Norian (Middle and Upper Triassic) floras of Australasia and elsewhere in Gondwana. Most specimens are distributed among three families: Umkomasiaceae, Peltaspermaceae and Matatiellaceae. These families, together with other possibly pteridospermous genera, are reviewed herein. Diversity in these families apparently declined by the Rhaetian and they did not persist into the Gondwanan post-Triassic. Australasian post-Triassic strata contain remarkably different floral assemblages to those of the Triassic. No fructifications are clearly pteridospermous and no remains show any obvious relationship with pteridosperms of the Gondwanan Triassic. Caytonialean fructifications are not known in Australasian strata; however, associated foliage has been reported from the Eastern Gondwanan Upper Triassic through Middle Jurassic including Australia. Much fern-like foliage, claimed to be pteridospermous from the Lower Jurassic through Eocene of Eastern Gondwana, lacks supporting evidence of such affiliation. (Author)

  16. Palaeoenvironmental vs. evolutionary control on size variation of coccoliths across the Lower-Middle Jurassic

    NARCIS (Netherlands)

    Ferreira, Jorge; Mattioli, Emanuela; van de Schootbrugge, Bas

    2017-01-01

    Size is an easily quantifiable trait probing the respective influence of evolution and palaeoenvironment on organisms through time. After the stressed period that spanned across western Tethys epicontinental seas during the early Toarcian, the following rebuilding of a restored water column ecosyste

  17. Opening of the Tethys in southwest China and its significance to the breakup of East Gondwanaland in late Paleozoic: Evidence from SHRIMP U-Pb zircon analyses for the Garzê ophiolite block

    Institute of Scientific and Technical Information of China (English)

    YAN Quanren; WANG Jianguo; ZHANG Dehui; ZHAO Jian; WANG Zongqi; LIU Shuwen; LI Qiugen; ZHANG Hongyuan; WANG Tao; LIU Dunyi; SHI Yuruo; JIAN Ping

    2005-01-01

    SHRIMP U-Pb zircon analyses for a gabbro sample from the Garzê ophiolite block yielded a mean 206Pb/238U age of 292±4 Ma, which indicated that the spreading time of the Garzê-Litang Tethys was most likely at the earliest Permian. Combined with previous studies, we suggest that the opening of the Tethys in southwest China was derived from breakup of the East Gondwanaland in the late Paleozoic.

  18. Bridging the Faraoni and Selli oceanic anoxic events: late Hauterivian to early Aptian dysaerobic to anaerobic phases in the Tethys

    Directory of Open Access Journals (Sweden)

    K. B. Föllmi

    2012-01-01

    Full Text Available A detailed geochemical analysis was performed on the upper part of the Maiolica Formation in the Breggia (southern Switzerland and Capriolo sections (northern Italy. The analysed sediments consist of well-bedded, partly siliceous, pelagic carbonate, which lodges numerous thin, dark and organic-rich layers. Stable-isotope, phosphorus, organic-carbon and a suite of redox-sensitive trace-element contents (RSTE: Mo, U, Co, V and As were measured. The RSTE pattern and Corg:Ptot ratios indicate that most organic-rich layers were deposited under dysaerobic rather than anaerobic conditions and that latter conditions were likely restricted to short intervals in the latest Hauterivian, the early Barremian and the pre-Selli early Aptian.

    Correlations are both possible with organic-rich intervals in central Italy (the Gorgo a Cerbara section and the Boreal Lower Saxony Basin, as well as with the facies and drowning pattern in the Helvetic segment of the northern Tethyan carbonate platform. Our data and correlations suggest that the latest Hauterivian witnessed the progressive installation of dysaerobic conditions in the Tethys, which went along with the onset in sediment condensation, phosphogenesis and platform drowning on the northern Tethyan margin, and which culminated in the Faraoni anoxic episode. This episode is followed by further episodes of dysaerobic conditions in the Tethys and the Lower Saxony Basin, which became more frequent and progressively stronger in the late early Barremian. Platform drowning persisted and did not halt before the latest early Barremian. The late Barremian witnessed diminishing frequencies and intensities in dysaerobic conditions, which went along with the progressive installation of the Urgonian carbonate platform. Near the Barremian-Aptian boundary, the increasing density in dysaerobic episodes in the Tethyan and Lower Saxony Basins is paralleled by a change towards heterozoan carbonate

  19. Constraints to the timing of Neo-Tethys closure determined from the Indus Group molasse, Ladakh Himalaya, NW India

    Science.gov (United States)

    Henderson, A. L.; Najman, Y.; Parrish, R. R.; Foster, G.; Garzanti, E.; Ando, S.

    2008-12-01

    The Indus Group is a Tertiary aged sequence composed of marine and terrestrial sedimentary rocks which were deposited in an evolving late-forearc to intermontane basin setting during the closure of Neo-Tethys and onset of India-Asia collision (Brookfield and Andrews-Speed 1984, Van Haver 1984, Searle 1990, Sinclair and Jaffey 2001, Clift et al. 2002). Clift et al. (2002) have constrained the age of collision by determining the lowermost stratigraphic point in the Indus Group that contains detritus from both Indian and Asian plates, and also by identifying where the Asian plate derived Indus Group unconformably overlies Indian plate margin sediments. The Chogdo Formation, dated by an overlying limestone at older than 50.5 Ma (Green et al. 2008) is identified by Clift et al. (2001), to be the oldest unit of the Indus Group to contain detritus from both the Indian and Asian plates, and to stratigraphically overly Lamayuru Group Indian slope turbidites and Jurutze forearc basin rocks, thereby constraining the timing of ocean closure at prior to 50.5 Ma. However, despite its importance, these previous evaluations of the Indus Group have been hampered by poor stratigraphic knowledge and uncertain lateral correlations, largely due to the relatively complex deformation of the rocks and poor biostratigraphic control. We use a combination of geological mapping, biostratigraphy, facies analysis, petrography, bulk rock geochemistry, and isotopic characterisation of single detrital grains to 1) create an accurate and more widely representative stratigraphy for the Indus Group, 2) determine the nature of the contacts which separate the overlying Indus Group from underlying Indian and Asian plate formations and 3) determine the provenance of the Group, in particular the stratigraphic level within the Indus Group at which both Indian and Asian plate detrital minerals occur together, in order to constrain the time of collision and discover which geological terranes where exhumed

  20. Rapid changes in the redox conditions of the western Tethys Ocean during the early Aptian oceanic anoxic event

    Science.gov (United States)

    Westermann, Stéphane; Stein, Melody; Matera, Virginie; Fiet, Nicolas; Fleitmann, Dominik; Adatte, Thierry; Föllmi, Karl B.

    2013-11-01

    The early Aptian (125 to 121 Ma) records an episode of severe environmental change including a major perturbation of the carbon cycle, an oceanic anoxic event (OAE 1a, 122.5 Ma), a platform drowning episode and a biocalcification crisis. We propose to trace changes in the oxygenation state of the ocean during the early Aptian anoxic event using the redox-sensitive trace-element (RSTE) distribution, phosphorus accumulation rates (PARs) and organic-matter characterization in three different basins of the western Tethys. The following sections have been investigated: Gorgo a Cerbara (central Italy) in the Umbria Marche basin, Glaise (SE France) in the Vocontian basin and Cassis/La Bédoule (SE France) located in the Provencal basin. In the Gorgo a Cerbara section, RSTE distributions show a low background level along the main part of the section, contrasted by different maxima in concentrations within the Selli level. In the Glaise section, the Goguel level displays a weak increase in RSTE contents coeval with moderate TOC values. At Cassis/La Bédoule, no significant RSTE enrichments have been observed in sediments equivalent to the Selli level. These differences in the records of the geochemical proxies of the Selli level or its equivalent indicate the deposition under different redox conditions, probably related to the paleogeography. Our data indicate the development of anoxic-euxinic conditions in the deeper part of the Tethys during OAE 1a, whereas in the shallower environments, conditions were less reducing. Moreover, at Gorgo a Cerbara, the Selli level is characterized by rapid changes in the intensity of reducing conditions in the water column. Ocean eutrophication seems to be a major factor in the development and the persistence of anoxia as suggested by the PAR evolution. Higher PAR values at the onset of OAE 1a suggest an increase in nutrient input, whereas the return to lower values through the first part of the OAE 1a interval may be related to the

  1. JURASSIC PALEONTOLOGICAL HERITAGE OF MURCIA (BETIC CORDILLERA, SOUTH-EASTERN SPAIN

    Directory of Open Access Journals (Sweden)

    GREGORIO ROMERO

    2004-03-01

    Full Text Available Jurassic rocks of the External and Internal Zones of the Betic Cordillera are widespread in the province of Murcia. Four areas are considered of special interest for stratigraphical and paleontological analysis: a Sierra Quípar and b Sierras Lúgar-Corque (External Subbetic, c Sierra Ricote (Median Subbetic and d Sierra Espuña (Malaguide Complex. The first two contain Jurassic sections including Sinemurian-Tithonian deposits, and major stratigraphic discontinuities, containing significant cephalopod concentrations of taphonomic and taxonomic interest, occuring in the Lower-Upper Pliensbachian, Lower/Middle Jurassic and Middle/Upper Jurassic boundaries. These areas are also relevant for biostratigraphical analysis of the Middle-Upper Jurassic interval. In the Sierra de Ricote, the Mahoma section is of especial interest for the study of Lías/Dogger transition. Casa Chimeneas section constitutes the best Subbetic site for the analysis of the Lower/Upper Bajocian boundary. In the La Bermeja-Casas de Vite area, the Bajocian-Tithonian interval is well-represented, including a parastratotype of the Radiolarite Jarropa Formation. Finally, the Malvariche section in Sierra Espuña represents the best Jurassic succession of Internal Zones of the Betic Cordillera and could be considered as a reference section for this Betic Domain. In this paper a heritage evaluation has been carried out for these classical jurassic sections with the object of protecting these sites according to the legal framework prevailing in the province of Murcia.

  2. The geographic and phylogenetic position of sauropod dinosaurs from the Kota formation (Early Jurassic) of India

    Science.gov (United States)

    Gillette, David D.

    2003-03-01

    The earliest sauropods are the Late Triassic Isanosaurus from Thailand, the Early Jurassic Barapasaurus and Kotasaurus from the Kota Formation of the Pranhita-Godavari Basin of India and Vulcanodon from Zimbabwe, and a variety of Middle Jurassic genera from many localities in Gondwana and Laurasia except North America. These early sauropod genera are related, but their phylogenetic positions remain unresolved. Sauropods originated in Laurasia (Thailand and vicinity) or Pangea (broadly, Thailand, China, India), with at least three additional steps involving expansion and diversification through the Middle Jurassic.

  3. POROSPHAERA (PORIFERA, A GLOBULAR SPONGE FROM THE UPPER JURASSIC OF THE CENTRAL IRAN

    Directory of Open Access Journals (Sweden)

    BABA SENOWBARI-DARYAN

    2011-11-01

    Full Text Available Porosphaera, an abundant small spherical calcisponge, well known from Cretaceous strata of Europe, was found in Middle and Upper Jurassic deposits of east-central Iran. This is the first record of Porosphaera from the Jurassic, except for a questionable occurrence of the genus from the Upper Jurassic of Canada, described by Jansa et al. (1982. The following species are new: P. regularis n. sp., P. biporata n. sp., P.? labyrinthica n. sp.,  and P.? asymmetrica n. sp. 

  4. Early Jurassic Flora and Stratigraphy from Shansonggang of Southern Jilin,China

    Institute of Scientific and Technical Information of China (English)

    Fengxiang Liu; Yuewu Sun; Chunlin Sun; Jiansheng Lu; Yanhua Zhao

    2003-01-01

    More than 35 species belonging to 22 genera of fossil plants are recognized by the authors from the Shansonggang flora in the 8hansonggang Basin of Jilin, China. Among them, the coexistence of Coniopteris and Cycadocarpidium demonstrates that the present flora possesses the characters of the early assemblage of Early Jurassic floras in Eurasia. Therefore, the age of the Shansonggang flora is considered the Early Jurassic.This study would be beneficial for better understanding the paleoecological and paleoclimatic characteristics of the Shansonggang Basin. Based mainly on the characters of the flora, the authors suggest that the Lower Jurassic coal-bearing strata, the Shansongang Formation, should namely be renewed.

  5. Molecular composition and ultrastructure of Jurassic paravian feathers.

    Science.gov (United States)

    Lindgren, Johan; Sjövall, Peter; Carney, Ryan M; Cincotta, Aude; Uvdal, Per; Hutcheson, Steven W; Gustafsson, Ola; Lefèvre, Ulysse; Escuillié, François; Heimdal, Jimmy; Engdahl, Anders; Gren, Johan A; Kear, Benjamin P; Wakamatsu, Kazumasa; Yans, Johan; Godefroit, Pascal

    2015-08-27

    Feathers are amongst the most complex epidermal structures known, and they have a well-documented evolutionary trajectory across non-avian dinosaurs and basal birds. Moreover, melanosome-like microbodies preserved in association with fossil plumage have been used to reconstruct original colour, behaviour and physiology. However, these putative ancient melanosomes might alternatively represent microorganismal residues, a conflicting interpretation compounded by a lack of unambiguous chemical data. We therefore used sensitive molecular imaging, supported by multiple independent analytical tests, to demonstrate that the filamentous epidermal appendages in a new specimen of the Jurassic paravian Anchiornis comprise remnant eumelanosomes and fibril-like microstructures, preserved as endogenous eumelanin and authigenic calcium phosphate. These results provide novel insights into the early evolution of feathers at the sub-cellular level, and unequivocally determine that melanosomes can be preserved in fossil feathers.

  6. Paleomagnetic studies on sedimentary Jurassic rocks from southern Bulgaria

    Science.gov (United States)

    Kruczyk, J.; Kaḑziałko-Hofmokl, M.; Nozharov, P.; Petkov, N.; Nachev, I.

    Paleomagnetic investigations were performed on Jurassic sediments sampled in the mobile area of Bulgaria comprising Srednogorie, Kreiste and Stranja. The main carriers of magnetic properties of rocks studied are pigmentary haematite and goethite of post-sedimentary origin. The characteristic component of natural remanence (CARM), isolated by means of analysis of demagnetization procedure is secondary, and was acquired after the main tectonic event that took place in this area during the Upper Cretaceous. The CARM directions before tectonic correction are close to the results for Upper Cretaceous magmatic rocks from Srednogorie. The mean CARM direction and the corresponding polar position obtained for the whole region studied are compared with reference data for the Eurasian Platform. The difference between the reference and our data implies anticlockwise rotation of southern Bulgaria relative to Eurasia by ˜ 10-20° and a northward tilt of the region under study by ˜ 10-15° after acquisition of CARM.

  7. Three new Jurassic euharamiyidan species reinforce early divergence of mammals.

    Science.gov (United States)

    Bi, Shundong; Wang, Yuanqing; Guan, Jian; Sheng, Xia; Meng, Jin

    2014-10-30

    The phylogeny of Allotheria, including Multituberculata and Haramiyida, remains unsolved and has generated contentious views on the origin and earliest evolution of mammals. Here we report three new species of a new clade, Euharamiyida, based on six well-preserved fossils from the Jurassic period of China. These fossils reveal many craniodental and postcranial features of euharamiyidans and clarify several ambiguous structures that are currently the topic of debate. Our phylogenetic analyses recognize Euharamiyida as the sister group of Multituberculata, and place Allotheria within the Mammalia. The phylogeny suggests that allotherian mammals evolved from a Late Triassic (approximately 208 million years ago) Haramiyavia-like ancestor and diversified into euharamiyidans and multituberculates with a cosmopolitan distribution, implying homologous acquisition of many craniodental and postcranial features in the two groups. Our findings also favour a Late Triassic origin of mammals in Laurasia and two independent detachment events of the middle ear bones during mammalian evolution.

  8. An Undercover Angiosperm from the Jurassic of China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shaolin; WANG Xin

    2010-01-01

    Searching for early angiosperms is a riveting activity in botany because it helps to resolve the phylogenetic relationships among seed plants and among angiosperms themselves.One of the challenges for this job is what the target fossils look like.Most possibly early angiosperms may elude our scrutiny with gymnospermous appearances.This possibility becomes a reality in a Jurassic plant,Solaranthus gen.nov,which bears a peltaspermalean appearance and enclosed ovules.According to knowledge available hitherto,the latter feature makes it an angiosperm.However,such a feature is more likely to be eclipsed by its gymnospermous appearance.The early age and unexpected character assemblage of Solaranthus urge for a fresh look on the assumed-simple relationship between angiosperms and gymnosperms.Its resemblance to the order Peltaspermales favors the Mostly Male Theory.

  9. Geomagnetic field intensity in the middle jurassic - oligocene

    CERN Document Server

    Kurazhkovskii, A Yu; Klain, B I

    2014-01-01

    The present paper summarizes results of the studies on the intensity of geomagnetic field in the (167 - 23) Ma interval by sedimentary rocks of the Russian Plate and adjacent territories. The joint analysis of the data paleointensity obtained by sedimentary and thermomagnetized (from PINT12) rocks within this temporal interval is conducted. It is shown that the changes of the paleointensity were occurred chaotically. Alternating bursts and periods of quiet regime of the geomagnetic field are typical for intermittent processes and is a characteristic of the geological interval Jurassic-beginning of Paleogene. The distributions of the paleointensity corresponding to different intervals of geologic time were investigated. It is revealed that the cumulative distribution function (CDF) of the paleointensity values is best approximated by a power function. The indices of the power functions varied depending on geologic time intervals.The analysis of the paleomagnetic data suggests that the medium in which the geoma...

  10. Extreme adaptations for aquatic ectoparasitism in a Jurassic fly larva.

    Science.gov (United States)

    Chen, Jun; Wang, Bo; Engel, Michael S; Wappler, Torsten; Jarzembowski, Edmund A; Zhang, Haichun; Wang, Xiaoli; Zheng, Xiaoting; Rust, Jes

    2014-06-24

    The reconstruction of ancient insect ectoparasitism is challenging, mostly because of the extreme scarcity of fossils with obvious ectoparasitic features such as sucking-piercing mouthparts and specialized attachment organs. Here we describe a bizarre fly larva (Diptera), Qiyia jurassica gen. et sp. nov., from the Jurassic of China, that represents a stem group of the tabanomorph family Athericidae. Q. jurassica exhibits adaptations to an aquatic habitat. More importantly, it preserves an unusual combination of features including a thoracic sucker with six radial ridges, unique in insects, piercing-sucking mouthparts for fluid feeding, and crocheted ventral prolegs with upward directed bristles for anchoring and movement while submerged. We demonstrate that Q. jurassica was an aquatic ectoparasitic insect, probably feeding on the blood of salamanders. The finding reveals an extreme morphological specialization of fly larvae, and broadens our understanding of the diversity of ectoparasitism in Mesozoic insects.DOI: http://dx.doi.org/10.7554/eLife.02844.001.

  11. Triassic-Jurassic Mass Extinction: Evidence for Bolide Impact?

    Science.gov (United States)

    Perry, R.; Becker, L.; Haggart, J.; Poreda, R.

    2003-04-01

    The Triassic-Jurassic (TJ) mass extinction event is one of the most severe in geologic history and is one of the five largest in the Phanerozoic with as many as 80% of the species lost. It is also one of the most poorly understood. Only a few geologic sections have been identified for the TJ extinction and most of those are not well preserved. Previously, the paucity of suitable stratigraphic sections has prevented corroborative geochemical studies. Recently a well-preserved stratigraphic section spanning the Triassic-Jurassic boundary (˜200 mya) was identified at Kennecott Point, Queen Charlotte, Islands, British Columbia. Initial studies have shown that the Kennecott Point sequence is one of the best preserved and contains one of the most complete radiolarian microfossil turnovers known. Analyses of stable isotopes have shown that a 13C perturbation exits within the sequence and suggests a decline in organic productivity (Ward et al., 2001). Preliminary results of laser desorption mass spectrometry (LDMS) of selected Queen Charlotte samples suggest that fullerenes (C60 to C200) may be present in the Kennecott Point stratigraphic sequence. Previous studies have shown that fullerenes are present in the mass extinction boundary of the Permian-Triassic (˜251 mya) as well as the well-known "dinosaur" extinction event of the Cretaceous-Tertiary (˜65 mya). Therefore, three of the big five extinction events appear to have associated fullerenes. The possible presence of fullerenes along with the productivity collapse (rapid environmental change) suggests that a cometary or asteroidal impact may have occurred. Although no known impact crater exists, we hope to present chemical evidence that an impact or multiple impacts may have been responsible for the TJ mass extinction.

  12. Porphyrin geochemistry of Atlantic Jurassic-Cretaceous black shales

    Energy Technology Data Exchange (ETDEWEB)

    Baker, E.W.; Louda, J.W.

    1986-01-01

    Late Jurassic-early Cretaceous black shales and an overlying sequence of Albian-Campanian zeolitic claystones from the Falkland Plateau (DSDP/IPOD Leg 71, Site 511) were analyzed for tetrapyrrole pigment type and abundance. The black shale sequence was found to be rich in DPEP-series dominated free-base, nickel (Ni) and, to a lesser extent, vanadyl (V = 0) porphyrins. A low level of organic maturity (i.e. precatagenesis) is indicated for these strata as nickel chelation by free-base porphyrins is only 50-75% complete, proceeding down-hole to 627 meters sub-bottom. Electronic and mass spectral data reveal that the proposed benzo-DPEP (BD) and tetrahydrobenzo-DPEP (THBD) series are present in the free-base and Ni species, as well as the more usual occurrence in V = 0 porphyrin arrays. Highly reducing conditions are suggested by an abundance of the PAH perylene, substantial amounts of the THBD/BD series and a redox equilibrium between free-base DPEP and 7,8-dihydro-DPEP series, which exist in a 7:1 molar ratio. The Albian-Campanian claystone strata were found to be tetrapyrrole poor, and those pigments present were typed as Cu/Ni highly dealkylated (C/sub 26/ max.) etioporphyrins, thought to be derived via redeposition and oxidation of terrestrial organic matter (OM). Results from the present study are correlated to their past analyses of Jurassic-Cretaceous sediments from Atlantic margins in an effort to relate tetrapyrrole quality and quantity to basin evolution and OM sources in the proto-Atlantic.

  13. Remagnetization and Clay diagenesis in Jurassic Sediments of Skye, Scotland

    Science.gov (United States)

    Basu, A.; Elliott, W.; Wampler, J.; Elmore, R.; Engel, M. H.

    2003-12-01

    The thrust of this study is to test the hypothesized connection between magnetite authigenesis and diagenetic reactions forming illite, an idea based on the results of paleomagnetic, rock magnetic, geochemical, and petrographic/SEM studies on Jurassic sedimentary rocks of Skye, Scotland. The Jurassic rocks in southern Skye contain a dual polarity magnetization residing in magnetite that is interpreted as a chemical remanent magnetization (CRM) and has directions similar to those of early Tertiary igneous rocks on Skye. The presence-absence test and the timing of acquisition for this CRM suggest that magnetite authigenesis is related to the smectite-to-illite conversion, and that clay diagenesis is a viable remagnetization mechanism. The clay fractions consist of illite-smectite (I-S), kaolinite, and trace amounts of chlorite. The I-S exhibits Kalkberg order (IISI) and typically contains ˜ 85% to 90% illite layers based on the positions of the 001 reflection. The 2M1, 1M and 1Md illite polytypes are present in variable proportions depending on size fraction. The K-Ar dates of I-S in the finest fraction range from 100 to 131 Ma while the K-Ar dates of I-S of the coarse fractions range from 160-210 Ma. In all cases, the dates of the finest I-S are much greater than the Tertiary CRM ages recorded in these rocks (65 Ma). The K-Ar dates decrease with decrease in particle size. At first approximation, the decrease is thought to reflect smaller amounts of detrital illite in the finer fractions. The youngest K-Ar dates of I-S are significantly greater than the CRM age recorded in these sediments. The most likely explanation of the discordance between K-Ar dates and CRM is that the finest fractions contain small amounts of detrital illite.

  14. Distribution of trace elements in organs of six species of cetaceans from the Ligurian Sea (Mediterranean), and the relationship with stable carbon and nitrogen ratios

    Energy Technology Data Exchange (ETDEWEB)

    Capelli, R. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Das, K. [MARE center, Laboratory for Oceanology, University of Liege, B6 Sart-Tilman, B-4000 Liege (Belgium); Pellegrini, R. De; Drava, G. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Lepoint, G. [MARE center, Laboratory for Oceanology, University of Liege, B6 Sart-Tilman, B-4000 Liege (Belgium); Miglio, C. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Minganti, V. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy)], E-mail: minganti@dictfa.unige.it; Poggi, R. [Museo Civico di Storia Naturale ' Giacomo Doria' - Via Brigata Liguria, 9 I-16121 Genova (Italy)

    2008-02-15

    Mercury (total and organic), cadmium, lead, copper, iron, manganese, selenium and zinc concentrations were measured in different organs of 6 different cetacean species stranded in an area of extraordinary ecological interest (Cetaceans' Sanctuary of the Mediterranean Sea) along the coast of the Ligurian Sea (North-West Mediterranean). Stable-isotopes ratios of carbon ({sup 13}C/{sup 12}C) and nitrogen ({sup 15}N/{sup 14}N) were also measured in the muscle. A significant relationship exists between {sup 15}N/{sup 14}N, mercury concentration and the trophic level. The distribution of essential and non-essential trace elements was studied on several organs, and a significant relationship between selenium and mercury, with a molar ratio close to 1, was found in the cetaceans' kidney, liver and spleen, regardless of their species. High selenium concentrations are generally associated with a low organic to total mercury ratio. While narrow ranges of concentrations were observed for essential elements in most organs, mercury and selenium concentrations are characterised by a wide range of variation. Bio-accumulation and bio-amplification processes in cetaceans can be better understood by comparing trace element concentrations with the stable-isotopes data.

  15. Occurrence of sauropod dinosaur tracks in the Upper Jurassic of Chile (redescription of Iguanodonichnus frenki)

    Science.gov (United States)

    Moreno, Karen; Benton, Michael J.

    2005-12-01

    New observations from the only studied Upper Jurassic dinosaur unit in South America, the Baños del Flaco Formation, Chile, are presented herein. The original description of the ichnospecies Iguanodonichnus frenki contains several mistakes and information that needs updating. Therefore, we provide a redescription, including new data collected in the field, that supports I. frenki as a sauropod in origin on the basis of the following features: step angles average less than 110°; pes prints intersect the trackway midline; pes prints are longer than wide, with the long axis rotated outward; the claw impression of digit I is prominent and directed forward; and claws on digits II, III, and IV are strongly reduced. These morphological characteristics might give clues about the pes morphology of the South American Jurassic sauropods, whose foot bone remains are scarce. The presence of this sauropod ichnospecies in the Late Jurassic agrees with Early-Middle Jurassic faunal associations in South America.

  16. Fe-Ni Micrometorites from Upper Jurassic Cañadon Asfalto Fm., Patagonia, Argentina

    Science.gov (United States)

    Matteini, M.; Hauser, N.; Cabaleri, N.; Silva Nieto, D.; Cuadros, F. A.; Reyes, S.

    2014-09-01

    Microspherules from an upper Jurassic sediments from Patagonia, show mineralogical, geochemical and textural features very similar to those reported for I-type micrometeorites whereas some spherules are interpreted as typical G-type micrometeorites.

  17. Hettangian (early jurassic) plant fossils from Puale Bay (peninsular terrane, Alaska)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Middle Hettangian (Early Jurassic) plant macrofossils from the Kamishak Formation at Puale Bay,Alaska occur mainly as leaves and leafy shoots found together with...

  18. Two new species of Paramesosciophilodes (Diptera, Nematocera, Mesosciophilidae from the Middle Jurassic of China

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    Jiaqi Gao

    2015-07-01

    Full Text Available Two new species, Paramesosciophilodes bellus sp. n. and Paramesosciophilodes rarissima sp. n., from the Jiulongshan Formation at Daohugou Village, Inner Mongolia, China, are described in the extinct family Mesosciophilidae. Altogether seven genera with 21 species of mesosciophilids have been described from the Jurassic of Siberia and Kazakhstan, the Lower Cretaceous of Transbaikalia, and the Middle Jurassic of Inner Mongolia. An emended generic diagnosis of Paramesosciophilodes and a list of known taxa of mesosciophilids are provided.

  19. Two new species of Paramesosciophilodes (Diptera, Nematocera, Mesosciophilidae) from the Middle Jurassic of China.

    Science.gov (United States)

    Gao, Jiaqi; Shi, Guifeng; Shih, Chungkun; Ren, Dong

    2015-01-01

    Two new species, Paramesosciophilodesbellus sp. n. and Paramesosciophilodesrarissima sp. n., from the Jiulongshan Formation at Daohugou Village, Inner Mongolia, China, are described in the extinct family Mesosciophilidae. Altogether seven genera with 21 species of mesosciophilids have been described from the Jurassic of Siberia and Kazakhstan, the Lower Cretaceous of Transbaikalia, and the Middle Jurassic of Inner Mongolia. An emended generic diagnosis of Paramesosciophilodes and a list of known taxa of mesosciophilids are provided.

  20. The first euthemistid damsel-dragonfly from the Middle Jurassic of China (Odonata, Epiproctophora, Isophlebioptera

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    Yongjun Li

    2013-01-01

    Full Text Available Sinoeuthemis daohugouensis gen. et sp. n. is the first record of the isophlebiopteran family Euthemistidae from Middle Jurassic of northeast China, while previously this family was restricted to the early Late Jurassic Kazakhstan. This new finding allows us to emend the family diagnosis with hindwing characters. This new species shows a mixture of characters alternatively present in different genera of the two families Euthemistidae and Sphenophlebiidae.

  1. Water-mass evolution during the Cenomanian and Turonian from the proto-Tethys and Western Interior Seaway.

    Science.gov (United States)

    Eldrett, James; Dodsworth, Paul; Bergman, Steven

    2016-04-01

    The Cenomanian and Turonian Stages were characterized by sustained global greenhouse climate conditions, emplacement of several Large Igneous Provinces (LIPs), oceanic anoxic events (OAE), and major global perturbations in the carbon cycle. Here we present detailed palynological and geochemical data from cores located along a North-South transect from the Western Interior Seaway (WIS) to the western proto-Tethys (Demerara Rise). Our integrated dataset demonstrates the northward flow of an anoxic Tethyan water-mass into the WIS during the early-middle Cenomanian; followed by a major re-organisation during the latest Cenomanian- Turonian as a full connection with the Arctic- Boreal water-mass was established during peak transgression, resulting in the de-stratification of the water column and improved oxygenation throughout the WIS and as far south as the Demerara Rise. These data suggest that the recorded decline in redox-sensitive trace metals reflect a genuine ventilation event and not a reduction in the trace metal global inventories. These long term trends in water-mass evolution are tentatively linked to third order eustatic transgression-regression cycles driven by regional tectonic and/or mantle plume-lithosphere dynamics associated with the emplacement of LIPs during this time. On shorter timescales (4th, 5th order) there is no evidence for global eustacy in the Greenhouse Cenomanian - Turonian with most of the bed-scale variations controlled by Milankovitch-driven variations in marine carbonate, siliceous, organic matter productivities and orbital influences on ocean-atmosphere-climate dynamics.

  2. Broad-scale patterns of late jurassic dinosaur paleoecology.

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    Christopher R Noto

    Full Text Available BACKGROUND: There have been numerous studies on dinosaur biogeographic distribution patterns. However, these distribution data have not yet been applied to ecological questions. Ecological studies of dinosaurs have tended to focus on reconstructing individual taxa, usually through comparisons to modern analogs. Fewer studies have sought to determine if the ecological structure of fossil assemblages is preserved and, if so, how dinosaur communities varied. Climate is a major component driving differences between communities. If the ecological structure of a fossil locality is preserved, we expect that dinosaur assemblages from similar environments will share a similar ecological structure. METHODOLOGY/PRINCIPAL FINDINGS: This study applies Ecological Structure Analysis (ESA to a dataset of 100+ dinosaur taxa arranged into twelve composite fossil assemblages from around the world. Each assemblage was assigned a climate zone (biome based on its location. Dinosaur taxa were placed into ecomorphological categories. The proportion of each category creates an ecological profile for the assemblage, which were compared using cluster and principal components analyses. Assemblages grouped according to biome, with most coming from arid or semi-arid/seasonal climates. Differences between assemblages are tied to the proportion of large high-browsing vs. small ground-foraging herbivores, which separates arid from semi-arid and moister environments, respectively. However, the effects of historical, taphonomic, and other environmental factors are still evident. CONCLUSIONS/SIGNIFICANCE: This study is the first to show that the general ecological structure of Late Jurassic dinosaur assemblages is preserved at large scales and can be assessed quantitatively. Despite a broad similarity of climatic conditions, a degree of ecological variation is observed between assemblages, from arid to moist. Taxonomic differences between Asia and the other regions demonstrate at

  3. Chasing the Late Jurassic APW Monster Shift in Ontario Kimberlites

    Science.gov (United States)

    Kent, D. V.; Muttoni, G.; Gee, J. S.; Kjarsgaard, B. A.

    2012-12-01

    A 30° gap was recognized in a composite APW path when global poles from predominantly igneous rocks were assembled in North American coordinates using plate reconstructions (Kent & Irving 2010 JGR). The 'monster shift' occurred between a 160-190 Ma cluster of mean poles at 75-80°N 90-110°E to a 140-145 Ma grouping centered at 60-65°N ~200°E. There are hardly any intermediate igneous poles whereas the rather divergent directions from the Late Jurassic Morrison Formation published by Steiner & Helsley (1975 GSA Bulletin) are subject to adjustments for Colorado Plateau rotation and sedimentary inclination error, neither of which are precisely known for this redbed unit sampled in Colorado. On the other hand, similar large rapid swings have been recognized in the Late Jurassic APW path for Adria (Channell et al. 2010 Paleo3), suggesting a global phenomena. In an effort to fill the data gap between ~145 and 160 Ma, we sampled accessible outcrops/subcrops of kimberlites in the Timiskaming area of Ontario, Canada, that are associated with high precision U-Pb perovskite ages (Heamon & Kjarsgaard 2000 EPSL). We report initial results from two of the intrusions: the 153.6±2.4 Ma Peddie kimberlite from outcrop and the Triple B kimberlite that was accessible by trenching and is assumed to be the same age as the nearby 153.7±1.8 Ma Seed kimberlite as delineated by aeromagnetic surveys and borings. Systematic progressive thermal demagnetization indicated in each unit a dominant characteristic component with unblocking temperatures to 575° that presumably reflect a magnetite carrier that will be checked by further rock magnetic experiments. Samples from the Peddie kimberlite had stable downward (normal polarity) magnetizations whose mean direction gives a paleopole at 73°N 184°E. In contrast, samples from the Triple B kimberlite have upward (reverse polarity) magnetizations with a well-grouped direction whose (north) paleopole is 78°N 197°E, proximal to the Peddie

  4. Organic matter recycling in a beach environment influenced by sunscreen products and increased inorganic nutrient supply (Sturla, Ligurian Sea, NW Mediterranean).

    Science.gov (United States)

    Misic, Cristina; Covazzi Harriague, Anabella; Trielli, Francesca

    2011-04-01

    The beaches are sites where the human influence may be strong and the beach ecosystems have often shown a high sensibility to environmental alterations. These zones may be affected by a large series of anthropogenic-derived pressures, such as unbalanced inorganic nutrient input, that may cause anomalous development of primary production, altering the structure of the trophic webs. Furthermore, the utilisation of cosmetic sunscreen products is reaching unexpected levels, thus assuming a potentially important as well as unknown role in the contamination of marine environments. The present study was planned to test the response of the beach ecosystem to increases in inorganic nutrients (nitrate and phosphate) and to the input of a widely used cosmetic sunscreen product. A short-term laboratory experiment was carried out on microsystems consisting of sediments and seawater from the swash zone of a Ligurian city beach (Sturla). The processes related to organic matter (OM) recycling and some microbial food web components (bacteria and micro-autotrophic organisms) were analysed. The multivariate statistical analysis of the results showed that the increase in inorganic nutrients and sunscreen caused only a transient alteration in the OM recycling processes in the seawater. The sedimentary processes, instead, were different in the different systems, although starting from the same condition. In the sediment, surprisingly, an increase in inorganic nutrients did not lead to an increase in the primary biomass nor to significantly higher bacterial abundance, while the sunscreen caused increased OM recycling, especially devoted to protein and lipid mobilisation, supporting a growing bacterial and autotrophic community by reducing the bottom-up pressure. Additional toxicity tests performed on protozoa highlighted that, while the inorganic nutrients seemed to show no effects, sunscreen decreased the protozoan viability, thus likely favouring microautotrophic and bacterial

  5. THE TRIASSIC/JURASSIC BOUNDARY IN THE ANDES OF ARGENTINA

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    ALBERTO C. RICCARDI

    2004-03-01

    Full Text Available The Arroyo Malo Formation at Alumbre Creek, on the northern bank of the Atuel River, west central Argentina, comprises a c. 300 m thick continuous marine succession across the Triassic-Jurassic System boundary, consisting of massive and laminated pelites indicative of a slope depositional environment. Late Triassic invertebrates, including ammonoids, nautiloids, bivalves, gastropods, brachiopods and corals are restricted to the lower 150 m. Beds between 125-135 m from the bottom yield Choristoceras cf. marshi Hauer, a species found in the Marshi/Crickmayi Zone of Europe and North America, together with loose fragments of Psiloceras cf. pressum Hillebrandt, coeval with the lower to middle part of the Hettangian Planorbis Zone. About 80 m higher are beds yielding Psiloceras cf. rectocostatum Hillebrandt, a species that gives name to an Andean biozone partially coeval with the Johnstoni and Plicatulum Subzones, upper Planorbis Zone. Other fossils recorded in the Rhaetian strata of this section are foraminifers, ostracods and plant remains identified as Zuberia cf. zuberi (Szaj. Freng. and Clathropteris sp. The section was also sampled for conodonts and radiolarians, thus far with negative results. A palaeomagnetic study is underway.

  6. Post-Jurassic mammal-like reptile from the Palaeocene.

    Science.gov (United States)

    Fox, R C; Youzwyshyn, G P; Krause, D W

    1992-07-16

    Mammal-like reptiles of the order Therapsida document the emergence of mammals from more primitive synapsids and are of unique zoological and palaeontological interest on that account. Therapsids, first appearing in the Early Permian, were thought to become extinct in the Middle Jurassic, soon after the Late Triassic origin of mammals. Here, however, we report the discovery of a therapsid from the late Palaeocene, 100 million years younger than the youngest previous occurrence of the order. This discovery nearly doubles the stratigraphic range of therapsids and furnishes their first record from the Cenozoic. The documenting fossils, an incomplete dentary containing three teeth, and four isolated teeth from other, conspecific individuals (Fig. 1), are from the Paskapoo Formation, at Cochrane, Alberta, Canada, from beds yielding a diverse mammalian fauna of early Tiffanian age. These specimens are catalogued in the collections of the University of Alberta Laboratory for Vertebrate Paleontology (UALVP) and provide the basis for a new taxon, as named and described below: (see text)

  7. Boron-containing organic pigments from a Jurassic red alga

    Science.gov (United States)

    Wolkenstein, Klaus; Gross, Jürgen H.; Falk, Heinz

    2010-01-01

    Organic biomolecules that have retained their basic chemical structures over geological periods (molecular fossils) occur in a wide range of geological samples and provide valuable paleobiological, paleoenvironmental, and geochemical information not attainable from other sources. In rare cases, such compounds are even preserved with their specific functional groups and still occur within the organisms that produced them, providing direct information on the biochemical inventory of extinct organisms and their possible evolutionary relationships. Here we report the discovery of an exceptional group of boron-containing compounds, the borolithochromes, causing the distinct pink coloration of well-preserved specimens of the Jurassic red alga Solenopora jurassica. The borolithochromes are characterized as complicated spiroborates (boric acid esters) with two phenolic moieties as boron ligands, representing a unique class of fossil organic pigments. The chiroptical properties of the pigments unequivocally demonstrate a biogenic origin, at least of their ligands. However, although the borolithochromes originated from a fossil red alga, no analogy with hitherto known present-day red algal pigments was found. The occurrence of the borolithochromes or their possible diagenetic products in the fossil record may provide additional information on the classification and phylogeny of fossil calcareous algae. PMID:20974956

  8. Eurycormus – Eurypoma, two Jurassic actinopterygian genera with mixed identity

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    G. Arratia

    2007-02-01

    Full Text Available Three Late Jurassic actinopterygian species are commonly placed in the genus Eurycormus: E. egertoni, E. grandis and E. speciosus. A detailed comparison supports an earlier assignment to two different genera, Eurycormus Wagner, 1863 (speciosus and Eurypoma Huxley, 1866 (E. egertoni and E. grande. Systematically, the two genera are only distantly related; Eurycormus belongs to the Teleosteomorpha, whereas Eurypoma is a halecomorph closely related to or a member of the Caturoidea within the Amiiformes. Drei oberjurassische Actinopterygier-Arten, egertoni, grandis und speciosus, werden gewöhnlich zur Gattung Eurycormus gestellt. Ein detaillierter Vergleich der drei Arten bestätigt eine frühere Zuordnung zu zwei verschiedenen Gattungen, Eurycormus Wagner, 1863 (speciosus und Eurypoma Huxley, 1866 (E. egertoni und E. grande, die zwei höheren Taxa innerhalb der Neopterygii zugeordnet werden: Eurycormus zu den Teleosteomorpha und Eurypoma zu den Amiiformes innerhalb der Halecomorphi, möglicherweise nahe oder innerhalb der Caturoidea. doi:10.1002/mmng.200600016

  9. Ichnological evidence of Megalosaurid Dinosaurs Crossing Middle Jurassic Tidal Flats.

    Science.gov (United States)

    Razzolini, Novella L; Oms, Oriol; Castanera, Diego; Vila, Bernat; Santos, Vanda Faria Dos; Galobart, Àngel

    2016-08-19

    A new dinosaur tracksite in the Vale de Meios quarry (Serra de Aire Formation, Bathonian, Portugal)preserves more than 700 theropod tracks. They are organized in at least 80 unidirectional trackways arranged in a bimodal orientation pattern (W/NW and E/SE). Quantitative and qualitative comparisons reveal that the large tridactyl, elongated and asymmetric tracks resemble the typical Late Jurassic-Early Cretaceous Megalosauripus ichnogenus in all morphometric parameters. Few of the numerous tracks are preserved as elite tracks while the rest are preserved as different gradients of modified true tracks according to water content, erosive factors, radial fractures and internal overtrack formations. Taphonomical determinations are consistent with paleoenvironmental observations that indicate an inter-tidal flat located at the margin of a coastal barrier. The Megalosauripus tracks represent the oldest occurrence of this ichnotaxon and are attributed to large megalosaurid dinosaurs. Their occurrence in Vale de Meios tidal flat represents the unique paleoethological evidence of megalosaurids moving towards the lagoon, most likley during the low tide periods with feeding purposes.

  10. Ichnological evidence of Megalosaurid Dinosaurs Crossing Middle Jurassic Tidal Flats

    Science.gov (United States)

    Razzolini, Novella L.; Oms, Oriol; Castanera, Diego; Vila, Bernat; Santos, Vanda Faria Dos; Galobart, Àngel

    2016-08-01

    A new dinosaur tracksite in the Vale de Meios quarry (Serra de Aire Formation, Bathonian, Portugal)preserves more than 700 theropod tracks. They are organized in at least 80 unidirectional trackways arranged in a bimodal orientation pattern (W/NW and E/SE). Quantitative and qualitative comparisons reveal that the large tridactyl, elongated and asymmetric tracks resemble the typical Late Jurassic-Early Cretaceous Megalosauripus ichnogenus in all morphometric parameters. Few of the numerous tracks are preserved as elite tracks while the rest are preserved as different gradients of modified true tracks according to water content, erosive factors, radial fractures and internal overtrack formations. Taphonomical determinations are consistent with paleoenvironmental observations that indicate an inter-tidal flat located at the margin of a coastal barrier. The Megalosauripus tracks represent the oldest occurrence of this ichnotaxon and are attributed to large megalosaurid dinosaurs. Their occurrence in Vale de Meios tidal flat represents the unique paleoethological evidence of megalosaurids moving towards the lagoon, most likley during the low tide periods with feeding purposes.

  11. Lower Jurassic beds with bivalves in south Slovenia

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    Irena Debeljak

    1995-12-01

    Full Text Available The Lower Jurassic beds of south Slovenia outcrop on a surface of several hundred km^ with their thickness in places exceeding 300 meters. They were deposited on the Dinaric Carbonate Platform. In them rich accumulations of characteristic bivalves occur that in Pliensbachian and Toarcian inhabited the wide interconnected shallow water regions of the western and southern margins of Tethysand the eastern Pacific. The most interesting are three large bivalve species:Lithiotis problematica, Cochlearites loppianus and Lithiopedalion scutatus.In addition, numerous other genera can be found: Gervilleiopema, Mytilus, Opisoma and Pachyrisma (with subgenera Pachymegalodon and Durga.The bivalves formed in the region of south Slovenia, in the prevailingly quiet environment of the restricted shelf, sea-bottom mats or biostromes. Their shells can be only rarely found in their growth position. The horizon with bivalves ("lithiotid horizon" in south Slovenia is attributed to Pliensbachian (Domerian. It isup to 75 metres thick and it almost does not pinch out. Within it individual lumachelles of bivalves occur which are from several centimetres to ten metres thick.They are almost exclusively associated with dark, micritic, in places marly limestone and bituminous dolomite. The biodiversity in lumachelles is very low. The intermediate beds that do not contain bivalves mostly consist of oolitic and biospariticlimestone. In this article some localities from various areas of the carbonate platform are described. Considered are paleogeographical and paleoecological conditions that permitted the existence of this typical bivalve fauna.

  12. Neuroanatomy of the marine Jurassic turtle Plesiochelys etalloni (Testudinata, Plesiochelyidae).

    Science.gov (United States)

    Carabajal, Ariana Paulina; Sterli, Juliana; Müller, Johannes; Hilger, André

    2013-01-01

    Turtles are one of the least explored clades regarding endocranial anatomy with few available descriptions of the brain and inner ear of extant representatives. In addition, the paleoneurology of extinct turtles is poorly known and based on only a few natural cranial endocasts. The main goal of this study is to provide for the first time a detailed description of the neuroanatomy of an extinct turtle, the Late Jurassic Plesiochelysetalloni, including internal carotid circulation, cranial endocast and inner ear, based on the first digital 3D reconstruction using micro CT scans. The general shape of the cranial endocast of P. etalloni is tubular, with poorly marked cephalic and pontine flexures. Anteriorly, the olfactory bulbs are clearly differentiated suggesting larger bulbs than in any other described extinct or extant turtle, and indicating a higher capacity of olfaction in this taxon. The morphology of the inner ear of P. etalloni is comparable to that of extant turtles and resembles those of slow-moving terrestrial vertebrates, with markedly low, short and robust semicircular canals, and a reduced lagena. In P. etalloni the arterial pattern is similar to that found in extant cryptodires, where all the internal carotid branches are protected by bone. As the knowledge of paleoneurology in turtles is scarce and the application of modern techniques such as 3D reconstructions based on CT scans is almost unexplored in this clade, we hope this paper will trigger similar investigations of this type in other turtle taxa.

  13. A New Basal Sauropod Dinosaur from the Middle Jurassic of Niger and the Early Evolution of Sauropoda

    Science.gov (United States)

    Remes, Kristian; Ortega, Francisco; Fierro, Ignacio; Joger, Ulrich; Kosma, Ralf; Marín Ferrer, José Manuel; Ide, Oumarou Amadou; Maga, Abdoulaye

    2009-01-01

    Background The early evolution of sauropod dinosaurs is poorly understood because of a highly incomplete fossil record. New discoveries of Early and Middle Jurassic sauropods have a great potential to lead to a better understanding of early sauropod evolution and to reevaluate the patterns of sauropod diversification. Principal Findings A new sauropod from the Middle Jurassic of Niger, Spinophorosaurus nigerensis n. gen. et sp., is the most complete basal sauropod currently known. The taxon shares many anatomical characters with Middle Jurassic East Asian sauropods, while it is strongly dissimilar to Lower and Middle Jurassic South American and Indian forms. A possible explanation for this pattern is a separation of Laurasian and South Gondwanan Middle Jurassic sauropod faunas by geographic barriers. Integration of phylogenetic analyses and paleogeographic data reveals congruence between early sauropod evolution and hypotheses about Jurassic paleoclimate and phytogeography. Conclusions Spinophorosaurus demonstrates that many putatively derived characters of Middle Jurassic East Asian sauropods are plesiomorphic for eusauropods, while South Gondwanan eusauropods may represent a specialized line. The anatomy of Spinophorosaurus indicates that key innovations in Jurassic sauropod evolution might have taken place in North Africa, an area close to the equator with summer-wet climate at that time. Jurassic climatic zones and phytogeography possibly controlled early sauropod diversification. PMID:19756139

  14. A new basal sauropod dinosaur from the middle Jurassic of Niger and the early evolution of sauropoda.

    Directory of Open Access Journals (Sweden)

    Kristian Remes

    Full Text Available BACKGROUND: The early evolution of sauropod dinosaurs is poorly understood because of a highly incomplete fossil record. New discoveries of Early and Middle Jurassic sauropods have a great potential to lead to a better understanding of early sauropod evolution and to reevaluate the patterns of sauropod diversification. PRINCIPAL FINDINGS: A new sauropod from the Middle Jurassic of Niger, Spinophorosaurus nigerensis n. gen. et sp., is the most complete basal sauropod currently known. The taxon shares many anatomical characters with Middle Jurassic East Asian sauropods, while it is strongly dissimilar to Lower and Middle Jurassic South American and Indian forms. A possible explanation for this pattern is a separation of Laurasian and South Gondwanan Middle Jurassic sauropod faunas by geographic barriers. Integration of phylogenetic analyses and paleogeographic data reveals congruence between early sauropod evolution and hypotheses about Jurassic paleoclimate and phytogeography. CONCLUSIONS: Spinophorosaurus demonstrates that many putatively derived characters of Middle Jurassic East Asian sauropods are plesiomorphic for eusauropods, while South Gondwanan eusauropods may represent a specialized line. The anatomy of Spinophorosaurus indicates that key innovations in Jurassic sauropod evolution might have taken place in North Africa, an area close to the equator with summer-wet climate at that time. Jurassic climatic zones and phytogeography possibly controlled early sauropod diversification.

  15. Discovery of the chitinozoans Belonechitina capitata from the Shiala Formation of northeastern Garhwal-Kumaon Tethys Himalaya, Pithoragarh District, Uttrakhand, India

    Institute of Scientific and Technical Information of China (English)

    H.N. Sinha; Jacques Verniers

    2016-01-01

    Belonechitina capitata, a typically middle to late Ordovician chitinozoan index taxon was for the first time recovered from the northeastern Kumaon region, a part of Garhwal-Kumaon Tethys basin of the Himalaya, India. This species is of great biostratigraphic importance and has already been reported from Avalonia, Baltica and northern Gondwana. The study area was during Ordovician, part of a low-palaeolatitudinal Gondwana region. The vesicles of recovered forms are black and fragmentary. This is principally attributed to intense tectonic activity during the Himalayan orogenic movement which resulted into high thermal alteration. The chitinozoans are found along with melanosclerites.

  16. Middle Jurassic Topawa group, Baboquivari Mountains, south-central Arizona: Volcanic and sedimentary record of deep basins within the Jurassic magmatic arc

    Science.gov (United States)

    Haxel, G.B.; Wright, J.E.; Riggs, N.R.; Tosdal, R.M.; May, D.J.

    2005-01-01

    Among supracrustal sequences of the Jurassic magmatic arc of the southwestern Cordillera, the Middle Jurassic Topawa Group, Baboquivari Mountains, south-central Arizona, is remarkable for its lithologic diversity and substantial stratigraphic thickness, ???8 km. The Topawa Group comprises four units (in order of decreasing age): (1) Ali Molina Formation-largely pyroclastic rhyolite with interlayered eolian and fluvial arenite, and overlying conglomerate and sandstone; (2) Pitoikam Formation-conglomerate, sedimentary breccia, and sandstone overlain by interbedded silt- stone and sandstone; (3) Mulberry Wash Formation-rhyolite lava flows, flow breccias, and mass-flow breccias, with intercalated intraformational conglomerate, sedimentary breccia, and sandstone, plus sparse within-plate alkali basalt and comendite in the upper part; and (4) Tinaja Spring Porphyry-intrusive rhyolite. The Mulberry Wash alkali basalt and comendite are genetically unrelated to the dominant calcalkaline rhyolite. U-Pb isotopic analyses of zircon from volcanic and intrusive rocks indicate the Topawa Group, despite its considerable thickness, represents only several million years of Middle Jurassic time, between approximately 170 and 165 Ma. Sedimentary rocks of the Topawa Group record mixing of detritus from a minimum of three sources: a dominant local source of porphyritic silicic volcanic and subvolcanic rocks, identical or similar to those of the Topawa Group itself; Meso- proterozoic or Cambrian conglomerates in central or southeast Arizona, which contributed well-rounded, highly durable, polycyclic quartzite pebbles; and eolian sand fields, related to Middle Jurassic ergs that lay to the north of the magmatic arc and are now preserved on the Colorado Plateau. As the Topawa Group evidently represents only a relatively short interval of time, it does not record long-term evolution of the Jurassic magmatic arc, but rather represents a Middle Jurassic "stratigraphic snapshot" of the arc

  17. Decoupling of carbon isotope records between organic matter and carbonate prior to the Toarcian Oceanic Anoxic Event (Early Jurassic)

    Science.gov (United States)

    Bodin, Stephane; Kothe, Tim; Krencker, Francois-Nicolas; Suan, Guillaume; Heimhofer, Ulrich; Immenhauser, Adrian

    2014-05-01

    Across the Pliensbachian-Toarcian boundary (P-To, Early Jurassic), ca. 1 Myr before the Toarcian Oceanic Anoxic Event (T-OAE), an initial negative carbon isotope excursion has been documented in western Tethys sedimentary rocks. In carbonate, its amplitude (2-3 permil) is similar to the subsequent excursion recorded at the onset of the T-OAE. Being also associated with a rapid warming event, the significance of this first carbon isotope shift, in terms of paleoenvironmental interpretation and triggering mechanism, remains however elusive. Taking advantage of expanded and rather continuous sections in the High Atlas of Morocco, several high-resolution, paired organic-inorganic carbon isotope records have been obtained across the Upper Pliensbachian - Lower Toarcian interval. At the onset of the T-OAE, an abrupt 1-2 permil negative shift is recorded in both organic and inorganic phases, succeeded by a relatively longer term 1-2 permil negative trend and a final slow return to pre-excursion conditions. In accordance with previous interpretations, this pattern indicates a perturbation of the entire exogenic carbon isotope reservoir at the onset of the T-OAE by the sudden release of isotopically light carbon into the atmosphere. By contrast, there is no negative shift in carbon isotopes for the P-To event recorded in bulk organic matter of Morocco. Given the strong dominance of terrestrial particles in the bulk organic matter fraction, this absence indicates that massive input of 12C-rich carbon into the atmosphere is not likely to have happened during the P-To event. A pronounced (2 permil) and abrupt negative shift in carbon isotope is however recorded in the bulk carbonate phase. We suggest that this decoupling between organic and inorganic phase is due to changes in the nature of the bulk carbonate phase. Indeed, the negative shift occurs at the lithological transition between Pliensbachian-lowermost Toarcian limestone-marl alternations and the Lower Toarcian marl

  18. UHP metamorphism in the Western Mediterranean : A tale of a Tethys fragment (Edough Massif, NE Algeria) and its geodynamic consequences

    Science.gov (United States)

    Bruguier, Olivier; Bosch, Delphine; Caby, Renaud; Fernandez, Laure; Abdallah, Nachida; Arnaud, Nicolas; Hammor, Dalila; Laouar, Rabah; Mechati, Medhi; Monié, Patrick; Ouabadi, Aziouz; Toubal, Abder

    2016-04-01

    Oligocene/early Miocene, thus unambiguously relating UHP metamorphism to the Alpine history. We suggest that the mafic protolith originates from the subducted retreating Calabrian branch of the Tethyan slab, that broke or tore, and which fragments were dragged upward and thrusted onto the North African margin, shortly before the formation of the Edough dome. Exhumation of these UHP units is coeval with the counter clockwise rotation of the Corsica-Sardinia block, which is associated to the extensional opening of the Ligurian Sea as a result of slab rollback (Faccenna et al., 2001). The early Miocene exhumation of the UHP units, which were detached from the downgoing plate, most likely resulted simultaneously from subduction rollback that was driven by slab pull.

  19. Variability in climate and productivity during the Paleocene-Eocene Thermal Maximum in the western Tethys (Forada section)

    Science.gov (United States)

    Giusberti, L.; Boscolo Galazzo, F.; Thomas, E.

    2016-02-01

    The Forada section (northeastern Italy) provides a continuous, expanded deep-sea record of the Paleocene-Eocene Thermal Maximum (PETM) in the central-western Tethys. We combine a new, high-resolution, benthic foraminiferal assemblage record with published calcareous plankton, mineralogical and biomarker data to document climatic and environmental changes across the PETM, highlighting the benthic foraminiferal extinction event (BEE). The onset of the PETM, occurring ˜ 30 kyr after a precursor event, is marked by a thin, black, barren clay layer, possibly representing a brief pulse of anoxia and carbonate dissolution. The BEE occurred within the 10 cm interval including this layer. During the first 3.5 kyr of the PETM, several agglutinated recolonizing taxa show rapid species turnover, indicating a highly unstable, CaCO3-corrosive environment. Calcareous taxa reappeared after this interval, and the next ˜9 kyr were characterized by rapid alternation of peaks in abundance of various calcareous and agglutinated recolonizers. These observations suggest that synergistic stressors, including deepwater CaCO3 corrosiveness, low oxygenation, and high environmental instability caused the extinction. Combined faunal and biomarker data (BIT index, higher plant n-alkane average chain length) and the high abundance of the mineral chlorite suggest that erosion and weathering increased strongly at the onset of the PETM, due to an overall wet climate with invigorated hydrological cycle, which led to storm flood events carrying massive sediment discharge into the Belluno Basin. This interval was followed by the core of the PETM, characterized by four precessionally paced cycles in CaCO3 %, hematite %, δ13C, abundant occurrence of opportunistic benthic foraminiferal taxa, and calcareous nannofossil and planktonic foraminiferal taxa typical of high-productivity environments, radiolarians, and lower δDn-alkanes. We interpret these cycles as reflecting alternation between an overall

  20. Benthic foraminifera at the Paleocene/Eocene thermal maximum in the western Tethys (Forada section): variability in climate and productivity

    Science.gov (United States)

    Giusberti, L.; Boscolo Galazzo, F.; Thomas, E.

    2015-09-01

    The Forada section (northeastern Italy) provides a continuous, expanded deep-sea record of the Paleocene/Eocene thermal maximum (PETM) in the central-western Tethys. We combine a new, high resolution, benthic foraminiferal assemblage record with published calcareous plankton, mineralogical and biomarker data to document climatic and environmental changes across the PETM, highlighting the benthic foraminiferal extinction event (BEE). The onset of the PETM, occurring ~ 30 kyr after a precursor event, is marked by a thin, black, barren clay layer, possibly representing a brief pulse of anoxia and carbonate dissolution. The BEE occurred within the 10 cm interval including this layer. During the first 3.5 kyr of the PETM several agglutinated recolonizing taxa show rapid species turnover, indicating a highly unstable, CaCO3-corrosive environment. Calcareous taxa reappeared after this interval, and the next ~ 9 kyr were characterized by rapid alternation of peaks in abundance of various calcareous and agglutinant recolonizers. These observations suggest that synergistic stressors including deep water CaCO3-corrosiveness, low oxygenation, and high environmental instability caused the extinction. Combined faunal and biomarker data (BIT index, higher plant n-alkane average chain length) and the high abundance of the mineral chlorite suggest that erosion and weathering increased strongly at the onset of the PETM, due to an overall wet climate with invigorated hydrological cycle, which led to storm flood-events carrying massive sediment discharge into the Belluno Basin. This interval was followed by the core of the PETM, characterized by four precessionally paced cycles in CaCO3%, hematite%, δ13C, abundant occurrence of opportunistic benthic foraminiferal taxa, as well as calcareous nannofossil and planktonic foraminiferal taxa typical of high productivity environments, radiolarians, and lower δDn-alkanes. We interpret these cycles as reflecting alternation between an

  1. The Oldest Jurassic Dinosaur: A Basal Neotheropod from the Hettangian of Great Britain.

    Science.gov (United States)

    Martill, David M; Vidovic, Steven U; Howells, Cindy; Nudds, John R

    2016-01-01

    Approximately 40% of a skeleton including cranial and postcranial remains representing a new genus and species of basal neotheropod dinosaur is described. It was collected from fallen blocks from a sea cliff that exposes Late Triassic and Early Jurassic marine and quasi marine strata on the south Wales coast near the city of Cardiff. Matrix comparisons indicate that the specimen is from the lithological Jurassic part of the sequence, below the first occurrence of the index ammonite Psiloceras planorbis and above the last occurrence of the Rhaetian conodont Chirodella verecunda. Associated fauna of echinoderms and bivalves indicate that the specimen had drifted out to sea, presumably from the nearby Welsh Massif and associated islands (St David's Archipelago). Its occurrence close to the base of the Blue Lias Formation (Lower Jurassic, Hettangian) makes it the oldest known Jurassic dinosaur and it represents the first dinosaur skeleton from the Jurassic of Wales. A cladistic analysis indicates basal neotheropodan affinities, but the specimen retains plesiomorphic characters which it shares with Tawa and Daemonosaurus.

  2. The Oldest Jurassic Dinosaur: A Basal Neotheropod from the Hettangian of Great Britain.

    Directory of Open Access Journals (Sweden)

    David M Martill

    Full Text Available Approximately 40% of a skeleton including cranial and postcranial remains representing a new genus and species of basal neotheropod dinosaur is described. It was collected from fallen blocks from a sea cliff that exposes Late Triassic and Early Jurassic marine and quasi marine strata on the south Wales coast near the city of Cardiff. Matrix comparisons indicate that the specimen is from the lithological Jurassic part of the sequence, below the first occurrence of the index ammonite Psiloceras planorbis and above the last occurrence of the Rhaetian conodont Chirodella verecunda. Associated fauna of echinoderms and bivalves indicate that the specimen had drifted out to sea, presumably from the nearby Welsh Massif and associated islands (St David's Archipelago. Its occurrence close to the base of the Blue Lias Formation (Lower Jurassic, Hettangian makes it the oldest known Jurassic dinosaur and it represents the first dinosaur skeleton from the Jurassic of Wales. A cladistic analysis indicates basal neotheropodan affinities, but the specimen retains plesiomorphic characters which it shares with Tawa and Daemonosaurus.

  3. Episodic Jurassic to Lower Cretaceous intraplate compression in Central Patagonia during Gondwana breakup

    Science.gov (United States)

    Navarrete, César; Gianni, Guido; Echaurren, Andrés; Kingler, Federico Lince; Folguera, Andrés

    2016-12-01

    From Lower Jurassic to Lower Cretaceous, several intraplate compression events affected discrete sectors of Central Patagonia, under a general context of crustal extension associated with Gondwana breakup. This was demonstrated by means of 2D and 3D seismic and borehole data, which show partial inversion of Lower and Middle Jurassic extensional structures of the Chubut and Cañadón Asfalto basins, during the earliest stages of breakup. A comparison with surrounding areas in Patagonia, where similar Jurassic intraplate compression was described, allowed the discrimination of three discrete pulses of subtle compression (C1: ∼188-185 Ma; C2: ∼170-163; C3: ∼157-136? Ma). Interestingly, episodic intraplate compressional events are closely followed by high flux magmatic events linked to the westward expansion of the Karoo-Ferrar thermal anomaly, which impacted on the lithosphere of southwest Gondwana in Lower Jurassic. In addition, we determined the approximate direction of the main compressive strain (σ1) compatible with other Jurassic intraplate belts of South America. These observations led us to propose a linkage between a thermo mechanically weakened continental crust due to LIPs activity, changes in plate motions and ridge-push forces generated by the opening of the Weddell Sea, in order to explain intraplate shortening, interrupted while Karoo LIPs magmatic invigoration took place.

  4. Palinspastic reconstruction and geological evolution of Jurassic basins in Mongolia and neighboring China

    Directory of Open Access Journals (Sweden)

    Wu Genyao

    2013-07-01

    Full Text Available The important event in Jurassic tectonics in Mongolia was the subduction and closure of the Mongolia-Okhotsk ocean; correspondingly, basin evolution can be divided into two main stages, related to the orogeny and collapse of the orogenic belt, respectively. The developing of Early–Middle Jurassic basins to the north of the ocean resulted from back-arc extension. The fossil sutures, from the China–SE Asia sub-continent to the south of the ocean, were rejuvenated by subduction-related orogeny; in addition, the Yanshanian intra-continental movement occurred. Three Early–Middle Jurassic molasse basins were developed by movement in Inner Mongolia, all of which stretched westwards (or northwards into Mongolia; therefore, the molasse basins in eastern and southern Mongolia had the same geometric and kinematic features as the basins in the Inner Mongolia. Owing to the collapse of the Mongolia-Okhotsk orogenic belt, a group of rift basins developed during the Late Jurassic. In eastern Mongolia, the NE orientated extensional basins were controlled by the neogenic NE-structure. The contemporary basins in southern Mongolia and the neighboring areas in China were constrained by remobilization (inherited activation of the latitudinal or ENE-directional basement structures. Three stages can be recognized in the evolution of the Early–Middle Jurassic basins after reversal; the basins also experienced four episodes of reformation.

  5. Neogene to recent contraction and basin inversion along the Nubia-Iberia boundary in SW Iberia

    Science.gov (United States)

    Ramos, Adrià; Fernández, Oscar; Terrinha, Pedro; Muñoz, Josep Anton

    2017-02-01

    The SW of Iberia is currently undergoing compression related to the convergence between Nubia and Iberia. Multiple compressive structures, and their related seismic activity, have been documented along the diffuse Nubia-Iberia plate boundary, including the Gorringe bank west of the Gulf of Cadiz, and the Betic-Rif orogen to the east. Despite seismic activity indicating a dominant compressive stress along the Algarve margin in the Gulf of Cadiz, the structures at the origin of this seismicity remain elusive. This paper documents the contractional structures that provide linkage across the Gulf of Cadiz and play a major role in defining the present-day seismicity and bathymetry of this area. The structures described in this paper caused the Neogene inversion of the Jurassic oblique passive margin that formed between the central Atlantic and the Ligurian Tethys. This example of a partially inverted margin provides insights into the factors that condition the inversion of passive margins.

  6. Early Jurassic allotherians from South Wales (United Kingdom

    Directory of Open Access Journals (Sweden)

    W. A. Clemens

    2007-02-01

    Full Text Available Fossils from two fissure fillings in Pant Quarry (designated Pant 4 and Pant 5, South Wales, United Kingdom, probably of Early Jurassic age document a taxonomically diverse vertebrate fauna, the Morganucodon-sphenodont fauna, composed of several kinds of reptiles, non-mammalian synapsids, and mammals. Six isolated molariform teeth from Pant 4 and 5 fissures clearly record the presence of Thomasia (Mammalia, Allotheria, Haramiyidae, a genus previously known only from purported Late Triassic faunas of southwestern England, France, Belgium, Luxemburg, Germany, and Switzerland. Small morphological differences from teeth in the larger English and continental European samples warrant identification of the Welsh material as Thomasia cf. moorei. The highly derived morphology of an isolated molariform tooth from Pant 5 fissure indicates the presence of another, possibly allotherian, taxon. Fossilien aus zwei wahrscheinlich unterjurassischen Spaltenfüllungen (Pant 4 und Pant 5 im Steinbruch Pant in Süd-Wales dokumentieren eine taxonomisch diverse Wirbeltierfauna. Diese Morganucodon-Sphenodontiden-Fauna besteht aus verschiedenen Formen von Reptilien, Synapsiden und Säugetieren. Sechs isolierte molariforme Zähne aus den Spaltenfüllungen Pant 4 und Pant 5 belegen eindeutig das Vorkommen von Thomasia (Mammalia, Allotheria, Haramiyidae, einer bisher nur aus vermutlich obertriassischen Faunen Südwest-Englands, Frankreichs, Belgiens, Luxemburgs, Deutschlands und der Schweiz bekannten Gattung. Geringe morphologische Unterschiede zu dem umfangreicheren Material aus England und Kontinental-Europa sprechen für die Identifikation des neuen Materials als Thomasia cf. moorei. Die stark abgeleitete Morphologie eines isolierten molariformen Zahnes aus der Spalte Pant 5 belegt das Vorkommen eines anderen Taxons, das möglicherweise auch den Allotheria zuzuordnen ist. doi:10.1002/mmng.200600018

  7. Anomalous enrichment of redox-sensitive trace elements in the marine black shales from the Duwi Formation, Egypt: Evidence for the late Cretaceous Tethys anoxia

    Science.gov (United States)

    Baioumy, Hassan; Lehmann, Bernd

    2017-09-01

    Marine black shale beds in the Duwi Formation of NE Egypt are part of the Late Cretaceous-Palaeogene Middle East-North African phosphogenic province. These black shales were analyzed for their redox-sensitive trace elements (V, Ni, Mo, U, Cu, Cr, Re, Cd, Sb, Tl, and Mn) to examine their depositional conditions. The data show that the black shales have elevated concentrations of redox-sensitive trace metals, low Mn contents, low Th/U and V/Mo ratios, and high V/Ni, Ni/Co, V/(V + Ni) and V/(V + Cr) ratios as well as a positive correlation of metal Mo to V concentrations. These geochemical data suggest that the Campanian-Maastrichtian Tethys was stratified and stagnant, with reducing bottom water conditions. The high V/Ni ratios in the study shales indicate their dominantly marine origin and suggest that the high-productivity upwelling system that persisted over ∼20 m.y. at the southern margins of the Tethys Ocean is the main source of the organic matter. A combination of elevated primary productivity, remineralization and reducing depositional conditions is the main control of enrichment of redox-sensitive trace elements in the black shales of the Duwi Formation.

  8. Malformations of calpionellid loricas recorded in Upper Jurassic and Lower Cretaceous pelagic carbonates of the Western Carpathians, Western Balcan, Mexico and Cuba - a tool for paleoenvironmental interpretation

    Science.gov (United States)

    Reháková, Daniela; Michalík, Jozef; Lakova, Iskra; Petrova, Silviya; López-Martínez, Rafael

    2017-04-01

    Characteristic morphology and assemblage composition of of ancient planktonic ciliate protozoan loricas made of them a favourable tool for interregional correlation. They are playing a key role in the biostratigraphy of Upper Jurassic/Lower Cretaceous sequences not only in areas lacking in ammonites. Detailed comparative analysis of calpionellid associations along all the Tethys shows variations in relative species abundance, variability, diversity changes and also in variability of their lorica structure. As oligotrophic organisms, they were sensitive to environmental perturbations such a change of the water temperature, chemistry, salinity and the nutrient supply. Mass occurrence of these microfossils was associated with shallow basins and with intrashelf elevations. These enviroments were characterized by a permanent current regime positively influencing the nutrient input. It is worth to mention, that the abundance and size of calpionellid loricas decrease towards the open sea - they are less frequent in deep basins, being very rare or seldom in reefal and lagoonal settings or in proximal settings with permanent river-influenced elevated nutrient level and with changes in surface water chemistry. Two diversity maxima were recorded within the Intermedia and the Oblonga subzones and two crisis were observed at the end of the Colomi Subzone and at the beginning of the Murgeanui Subzone. During the last mentioned events, deformations (aberrant morphology) were documented in Crassicollaria, Tintinnopsella and Praecalpionellites loricas (Reháková, 2000; Lakova and Petrova, 2013; López-Martínez et al., 2015). Teratological (malformed) tests may coincide either with metal poisoning or with salinity changes. Global climate changes could have been evoked by active volcanoes noted at this time (Casellato and Erba, 2015). Oxygen isotope data signalized late Tithonian cooling followed by a warming at the beginning of the Berriasian (Weissert and Erba, 2004). Huge

  9. The Jurassic of Denmark and Greenland: Early and Middle Jurassic mires of Bornholm and the Fennoscandian Border Zone: a comparison of depositional environments and vegetation

    Directory of Open Access Journals (Sweden)

    Koppelhus, Eva B.

    2003-10-01

    Full Text Available Suitable climatic conditions for peat formation existed during Early–Middle Jurassic times in the Fennoscandian Border Zone. Autochthonous peat and allochthonous organic matter were depositedfrom north Jylland, south-east through the Kattegat and Øresund area, to Skåne and Bornholm. The increase in coal seam abundance and thickness from north Jylland to Bornholm indicates that the most favourable peat-forming conditions were present towards the south-east. Peat formation and deposition of organic-rich muds in the Early Jurassic coastal mires were mainly controlled by a continuous rise of relative sea level governed by subsidence and an overall eustatic rise. Watertable rise repeatedly outpaced the rate of accumulation of organic matter and terminated peat formationby lacustrine or lagoonal flooding. Organic matter accumulated in open-water mires and in continuously waterlogged, anoxic and periodically marine-influenced mires. The latter conditionsresulted in huminite-rich coals containing framboidal pyrite. The investigated Lower Jurassic seams correspond to peat and peaty mud deposits that ranged from 0.5–5.7 m in thickness, but were generallyless than 3 m thick. It is estimated that on Bornholm, the mires existed on average for c. 1200 years in the Hettangian–Sinemurian and for c. 2300 years in the Late Pliensbachian; the Early Jurassic(Hettangian–Sinemurian mires in the Øresund area existed for c. 1850 years. Aalenian uplift of the Ringkøbing–Fyn High and major parts of the Danish Basin caused a significant change in the basinconfiguration and much reduced subsidence in the Fennoscandian Border Zone during the Middle Jurassic. This resulted in a more inland position for the Middle Jurassic mires which on occasionenabled peat accumulation to keep pace with, or temporarily outpace, watertable rise. Thus, peat formation was sometimes sustained for relatively long periods, and the mires may have existed for up to 7000 years in the

  10. The First Stegosaur (Dinosauria, Ornithischia) from the Upper Jurassic Shishugou Formation of Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    JIA Chengkai; Catherine A. FOSTER; XU Xing; James M. CLARK

    2007-01-01

    A new stegosaur species, Jiangjunosaurus junggarensis, gen. et sp. nov., is erected based on a specimen collected from the Upper Jurassic upper section of the Shishugou Formation in the Junggar Basin, Xinjiang, China. It represents the first stegosaur from the Jurassic of Xinjiang and increases the diversity of the dinosaur fauna in the Shishugou Formation. The new genus is characterized by symmetrical and proportionally wide tooth crowns, a sub-rectangular axial neural spine seen in lateral view, and large openings on the lateral surfaces of the cervical centra. A preliminary character analysis suggests that this new taxon is more derived than the Middle Jurassic stegosaur Huayangosaurus but more primitive than most other known stegosaur species.

  11. A New Sauropod, Gongxianosaurus, from the Lower Jurassic of Sichuan, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The paper describes an early and primitive sauropod dinosaur, Gongxianosaurus shibeiensis (gen. et sp. nov.), from the Dongyuemiao Member of the Lower Jurassic Ziliujing Formation in Shibei Township, Gongxian County, Sichuan Province, China, which is one of the 5 dinosaur fossils discovered in Gongxian in 1997. Except the skull which is incomplete, the fossils are well preserved. It has some features of both sauropods and prosauropods. It is an intermediate type in the evolution of dinosaurs from prosauropods to sauropods and provides materials for the study of the origin and evolution of the sauropod dinosaur fauna. The discovery of this new sauropod furnishes a way for the stratigraphic correlation between the Early Jurassic Ziliujing Formation in the Sichuan basin and the Lower Jurassic Lufeng Formation in the Central Yunnan basin.

  12. Three new species of mesosciophilid gnats from the Middle-Late Jurassic of China (insecta: Diptera: Nematocera: Mesosciophilidae).

    Science.gov (United States)

    Zhang, J F

    2008-11-15

    Three extinct new species from the Callovian or Oxfordian (uppermost Middle Jurassic or lowermost Upper Jurassic) Daohugou beds in Inner Mongolia, China is described as Mesosciophila abstracta sp. n., Mesosciophilodes synchrona sp. n. and Paramesosciophilodes eximia sp. n. (Family Mesosciophilidae). All the records of mesosciophilid gnats are briefly reviewed.

  13. First American record of the Jurassic ichnogenus Deltapodus and a review of the fossil record of stegosaurian footprints

    DEFF Research Database (Denmark)

    Milàn, Jesper; Chiappe, Luis M

    2009-01-01

    of a well-preserved pes track and the eroded remains of a manus track. Previously, Deltapodus was known only from the Middle Jurassic Yorkshire coast of England and the Upper Jurassic of Portugal and Spain. The new discovery thus substantially extends the geographic record of this ichnospecies...

  14. Methyl mercury distributions in relation to the presence of nano- and picophytoplankton in an oceanic water column (Ligurian Sea, North-western Mediterranean)

    Science.gov (United States)

    Heimbürger, Lars-Eric; Cossa, Daniel; Marty, Jean-Claude; Migon, Christophe; Averty, Bernard; Dufour, Aurélie; Ras, Josephine

    2010-10-01

    Recent findings on the distribution of methylated mercury (MeHg T) in waters have highlighted the importance of organic carbon remineralization on the production of these compounds in the open ocean. Here, we present the first time-series (20 monthly samplings between July 2007 and May 2009) of high-resolution vertical profiles (10-12 depths in a 2350 m water column) of MeHg T distributions in an open ocean environment, the Ligurian Sea (North-western Mediterranean Sea). Concentrations varied within the sub-picomolar range (general mean: 0.30 ± 0.17 pmol L -1, n = 214) with the lowest values at the surface, increasing with depth up to the oxygen minimum zone, and decreasing slowly at greater depth. Concentrations in the surface waters never exceeded 0.15 pmol L -1, while the highest concentrations (up to 0.82 pmol L -1) were associated to the hypoxycline during the autumn bloom. A detailed vertical MeHg T profile reveals a "double-peak" pattern, coincidental with the two microbial layers described by Tanaka and Rassoulzadegan (2002), the so-called "microbial food web" in the euphotic zone (microbial loop" in the aphotic zone (>100 m). Temporal variations in the MeHg T abundance and distribution in the water column were linked to seasonality. The highest MeHg T concentrations were found in the oxygen minimum zone during the period of stratification, and coincide with the greatest abundance of nano- and picophytoplankton (cyanobacteria, nanoflagellates, etc.) in the euphotic layer. None of our deep MeHg T measurements (˜100 m above the sea bottom) revealed a significant sedimentary source of MeHg T. We explored the correlation between MeHg T concentrations and the apparent oxygen utilization, a proxy of organic matter remineralization, over the study period. Results of this study strengthen the hypothesis that net mercury methylation in the open ocean occurs in the water column, is linked to organic matter regeneration, and is promoted by the presence of small

  15. Critical review of research on the Lower Jurassic flora of Poland

    Directory of Open Access Journals (Sweden)

    Pacyna Grzegorz

    2013-12-01

    Full Text Available The Lower Jurassic plant macrofossils of Poland are poorly known. Relatively rich sources of fossils are found in only a few outcrops in the Holy Cross Mountains. Other described plant remains come from drill cores taken from most areas of Poland, but as a rule these are single specimens. The only professional descriptions of Lower Jurassic macroflora are papers by Raciborski, Makarewiczówna, and a team of researchers consisting of Reymanówna, Barbacka, Ziaja, and Wcisło-Luraniec. Raciborski’s fossil collection is still available for research and revision. Such work is in progress. The collection described by Makarewiczówna contained many interesting specimens but unfortunately the majority of them are now missing. Stratigraphic research by geologists has provided some new specimens from drill cores and outcrops in the Holy Cross Mountains but these have not been subjected to detailed palaeobotanical analysis. The palynology of the Lower Jurassic was focused on biostratigraphy from the outset of that research. As an outcome it provided spore-pollen and megaspore zonations for Lower Jurassic strata in Poland. The Polish Lower Jurassic flora is comprised of ferns (very numerous, lycopsids, sphenopsids, cycadaleans, bennettitaleans, gnetaleans, ginkgoaleans, and conifers. This flora is taxonomically poorer than the equally old and geographically close floras of Denmark, Sweden, and Germany. Macrofloristic data have been used by geologists as an important source of information for assessing the age of Lower Jurassic formations, particularly in the Holy Cross Mountains. Hence the need for the old collections to be taxonomically revised and for new material from outcrops and drill cores to be examined and described.

  16. Storms in the deep: tempestite- and beach-like deposits in pelagic sequences (Middle-Upper Jurassic, Subbetic, South of Spain)

    Science.gov (United States)

    Pomar, Luis; Molina, Jose M.; Ruiz-Ortiz, Pedro A.; Vera, Juan A.

    2017-04-01

    Fine-peloidal- to coarse oolitic-bioclastic grainstones with hummocky cross stratification (HCS) occur interbedded in Middle-Upper Jurassic pelagic lime-mudstone successions (Betic ranges, Southern Spain). These strata were deposited in pelagic troughs and swells, away from continental areas, in the Southern Iberian Continental Margin of the Western Tethys. Previously interpreted as tempestites, mainly due to the attribution of the HCS to surface storm waves, they are now reinterpreted as the product of turbulence in deeper conditions. Among many, some selected examples are here presented. All of them share: 1) Grainstone beds are interbedded with pelagic mudstones and marls 2) Grainstone components were reworked by oscillatory flows superimposed to unidirectional tractive flows (unidirectional ripple lamination and HCS). 3) Components were either derived from shallow-water environments (e.g., ooids), or produced in pelagic conditions (e.g., radiolarians, Saccocoma, peloids, etc). 4) Although surface-storm tempestite flows can be required to bring downslope components from shallow-water settings, the grainstone beds reflect sediment reworking at a depth dominated by fine pelagic sedimentation. 5) Internal waves propagating along a pycnocline and breaking against a sloping surface are the best candidate to induce the sedimentary structures and sediment organization that characterize these grainstone beds. The examples here presented (Middle-Upper Jurassic of the Subbetic) include: a) Peloid grainstones interbedded with radiolarite marls deposited on the flanks of volcanic guyots. The interbedded lime muds and marls contain 'filaments', sponge spicules and radiolarians. b) Peloid-bioclastic (radiolarians, Saccocoma, etc.) grainstone beds with HCS, interbedded with pelagic lime muds. c) Coarse oolitic grainstone unit, encased in pelagic marls, with wedge-shaped crossbed-sets with gently seaward-dipping parallel lamination, and sets of low-angle up-slope dipping

  17. A basal alvarezsauroid theropod from the early Late Jurassic of Xinjiang, China.

    Science.gov (United States)

    Choiniere, Jonah N; Xu, Xing; Clark, James M; Forster, Catherine A; Guo, Yu; Han, Fenglu

    2010-01-29

    The fossil record of Jurassic theropod dinosaurs closely related to birds remains poor. A new theropod from the earliest Late Jurassic of western China represents the earliest diverging member of the enigmatic theropod group Alvarezsauroidea and confirms that this group is a basal member of Maniraptora, the clade containing birds and their closest theropod relatives. It extends the fossil record of Alvarezsauroidea by 63 million years and provides evidence for maniraptorans earlier in the fossil record than Archaeopteryx. The new taxon confirms extreme morphological convergence between birds and derived alvarezsauroids and illuminates incipient stages of the highly modified alvarezsaurid forelimb.

  18. Jurassic Lake T'oo'dichi': a large alkaline, saline lake, Morrison Formation, eastern Colorado Plateau

    Science.gov (United States)

    Turner, C.E.; Fishman, N.S.

    1991-01-01

    Recognition of alkaline, saline-lake deposits in the Morrison Formation significantly alters interpretations of depositional environments of this formation, and it also has important implications for paleoclimatic interpretation. Late Jurassic climate was apparently much more arid than had previously been thought. In fact, sedimentologic evidence suggests that the lake basin was typically dry for extended periods and enjoyed only brief wet intervals. This conclusion has important consequences for environmental interpretation of the habitat that was favorable for large herbivorous dinosaurs, which thrived in the Late Jurassic. -from Authors

  19. Androecium of Archaefructus, the Late Jurassic Angiosperms from Western Liaoning, China

    Institute of Scientific and Technical Information of China (English)

    SUN Ge; ZHENG Shaolin; SUN Chunlin; SUN Yuewu; David L. DILCHER; MIAO Yuyan

    2002-01-01

    Androecium of the earliest known flowering plant Archaefructus liaoningensis was found from the Upper Jurassic Jianshangou Formation of western Liaoning, China. The androecium consists of numerous stamens bearing in pair on the reproductive axes below conduplicate carpels. The stamens are composed of a short filament and basifixed anther for each. Monosulcate pollen in situ are found from the anthers. The characters of the androecium reveals that Archaefructus are probably protandrous, and the paired stamens and monosulcate pollen appear to indicate that Archaefructus, as primitive angiosperms,might be derived from extinct seed -ferns during the Older Mesozoic. Archaefructus is considered Late Jurassic in age.

  20. Early and Middle Jurassic climate changes: implications for palaeoceanography and tectonics

    DEFF Research Database (Denmark)

    Korte, Christoph; Hesselbo, Stephen; Ullmann, Clemens Vinzenz;

    2014-01-01

    three pronounced oxygen isotope ‘Ice Age’ cycles, and the subsequent well known Toarcian Oceanic Anoxic ‘supergreenhouse’ Event is followed by very warm seawater temperatures in the late Toarcian. Moreover, a very pronounced and effective cooling occurred during the latest Toarcian and early Aalenian...... (Early-Middle Jurassic Boundary Event) resulted in substantial expansion of Arctic climates to palaeolatitudes as low as 45° and in distinctly cooler seawater temperatures in lower latitude European seas. At least the extensive cooling at the Early-Middle Jurassic Boundary Event was most likely driven...

  1. Earliest evolution of multituberculate mammals revealed by a new Jurassic fossil.

    Science.gov (United States)

    Yuan, Chong-Xi; Ji, Qiang; Meng, Qing-Jin; Tabrum, Alan R; Luo, Zhe-Xi

    2013-08-16

    Multituberculates were successful herbivorous mammals and were more diverse and numerically abundant than any other mammal groups in Mesozoic ecosystems. The clade also developed diverse locomotor adaptations in the Cretaceous and Paleogene. We report a new fossil skeleton from the Late Jurassic of China that belongs to the basalmost multituberculate family. Dental features of this new Jurassic multituberculate show omnivorous adaptation, and its well-preserved skeleton sheds light on ancestral skeletal features of all multituberculates, especially the highly mobile joints of the ankle, crucial for later evolutionary success of multituberculates in the Cretaceous and Paleogene.

  2. The palaeogeography of Sundaland and Wallacea since the Late Jurassic

    Directory of Open Access Journals (Sweden)

    Robert Hall

    2013-08-01

    Full Text Available The continental core of Southeast (SE Asia, Sundaland, was assembled from Gondwana fragments by the Early Mesozoic. Continental blocks rifted from Australia in the Jurassic [South West (SW Borneo, East Java-West Sulawesi-Sumba], and the Woyla intraoceanic arc of Sumatra, were added to Sundaland in the Cretaceous. These fragments probably included emergent areas and could have carried a terrestrial flora and fauna. Sarawak, the offshore Luconia-Dangerous Grounds areas, and Palawan include Asian continental material. These probably represent a wide accretionary zone at the Asia-Pacific boundary, which was an active continental margin until the mid Cretaceous. Subduction ceased around Sundaland in the Late Cretaceous, and from about 80 Ma most of Sundaland was emergent, physically connected to Asia, but separated by deep oceans from India and Australia. India moved rapidly north during the Late Cretaceous and Early Cenozoic but there is no evidence that it made contact with SE Asia prior to collision with Asia. One or more arc-India collisions during the Eocene may have preceded India-Asia collision. The arcs could have provided dispersal pathways from India into SE Asia before final suturing of the two continents. During the Late Cretaceous and Early Cenozoic there was no significant subduction beneath Sumatra, Java and Borneo. At about 45 Ma Australia began to move north, subduction resumed and there was widespread rifting within Sundaland. During the Paleogene east and north Borneo were largely submerged, the Makassar Straits became a wide marine barrier within Sundaland, and West Sulawesi was separated from Sundaland but included land. By the Early Miocene the proto-South China Sea had been eliminated by subduction leading to emergence of land in central Borneo, Sabah and Palawan. Australia-SE Asia collision began, eliminating the former deep ocean separating the two continents, and forming the region now known as Wallacea. The microplate or

  3. Polar record of Early Jurassic massive carbon injection

    Science.gov (United States)

    Suan, Guillaume; Nikitenko, Boris L.; Rogov, Mikhail A.; Baudin, François; Spangenberg, Jorge E.; Knyazev, Valeriy G.; Glinskikh, Larisa A.; Goryacheva, Anna A.; Adatte, Thierry; Riding, James B.; Föllmi, Karl B.; Pittet, Bernard; Mattioli, Emanuela; Lécuyer, Christophe

    2011-12-01

    The Toarcian Oceanic Anoxic Event (T-OAE) (ca. 182 Myr, Early Jurassic) represents one of the best-recognized examples of greenhouse warming, decreased seawater oxygenation and mass extinction. The leading hypothesis to explain these changes is the massive injection of thermogenic or gas hydrate-derived 13C-depleted carbon into the atmosphere, resulting in a > 3 per mil negative carbon isotope excursion (CIE), accelerated nutrient input and dissolved oxygen consumption in the oceans. Nevertheless, the lack of a precisely dated record of the T-OAE outside low latitudes has led to considerable debate about both its temporal and spatial extent and hence concerning its underlying causes. Here we present new isotopic and lithological data from three precisely dated N Siberian sections, which demonstrate that mass extinction and onset of strong oxygen-deficiency occurred near synchronously in polar and most tropical sites and were intimately linked to the onset of a marked 6‰ negative CIE recorded by bulk organic carbon. Rock Eval pyrolysis data from Siberia and comparisons with low latitudes show that the CIE cannot be explained by the extent of stratification of the studied basins or changes in organic matter sourcing and suggest that the negative CIE reflects rapid 13C-depleted carbon injection to all exchangeable reservoirs. Sedimentological and palynological indicators show that the injection coincided with a change from cold (abundant glendonites and exotic boulder-sized clasts) to exceptionally warm conditions (dominance of the thermophyllic pollen genus Classopollis) in the Arctic, which likely triggered a rapid, possibly partly glacioeustatic sea-level rise. Comparisons with low latitude records reveal that warm climate conditions and poor marine oxygenation persisted in continental margins at least 600 kyr after the CIE, features that can be attributed to protracted and massive volcanic carbon dioxide degassing. Our data reveal that the T-OAE profoundly

  4. Ancient plate kinematics derived from the deformation pattern of continental crust: Paleo- and Neo-Tethys opening coeval with prolonged Gondwana-Laurussia convergence

    Science.gov (United States)

    Kroner, Uwe; Roscher, Marco; Romer, Rolf L.

    2016-06-01

    The formation and destruction of supercontinents requires prolonged convergent tectonics between particular plates, followed by intra-continental extension during subsequent breakup stages. A specific feature of the Late Paleozoic supercontinent Pangea is the prolonged and diachronous formation of the collisional belts of the Rheic suture zone coeval with recurrent continental breakup and subsequent formation of the mid-ocean ridge systems of the Paleo- and Neo-Tethys oceans at the Devonian and Permian margins of the Gondwana plate, respectively. To decide whether these processes are causally related or not, it is necessary to accurately reconstruct the plate motion of Gondwana relative to Laurussia. Here we propose that the strain pattern preserved in the continental crust can be used for the reconstruction of ancient plate kinematics. We present Euler pole locations for the three fundamental stages of the Late Paleozoic assembly of Pangea and closure of the Rheic Ocean: (I) Early Devonian (ca. 400 Ma) collisional tectonics affected Gondwana at the Armorican Spur north of western Africa and at the promontory of the South China block/Australia of eastern Gondwana, resulting in the Variscan and the Qinling orogenies, respectively. The Euler pole of the rotational axis between Gondwana and Laurussia is positioned east of Gondwana close to Australia. (II) Continued subduction of the western Rheic Ocean initiates the clockwise rotation of Gondwana that is responsible for the separation of the South China block from Gondwana and the opening of Paleo-Tethys during the Late Devonian. The position of the rotational axis north of Africa reveals a shift of the Euler pole to the west. (III) The terminal closure of the Rheic Ocean resulted in the final tectonics of the Alleghanides, the Mauritanides and the Ouachita-Sonora-Marathon belt, occurred after the cessation of the Variscan orogeny in Central Europe, and is coeval with the formation of the Central European Extensional

  5. The ataxioceratid ammonite fauna of the Tithonian (Upper Jurassic) of Casa Pincheira, Mendoza (Argentina)

    Science.gov (United States)

    Parent, Horacio

    2003-07-01

    The Tithonian Ataxioceratids from Casa Pincheira (Mendoza) are described in the framework of a period of global relative high sea level stand, with Andean basins well communicated with Central and Western Tethys. The family Ataxioceratidae is interpreted including the subfamily Torquatisphinctinae Tavera ( Katroliceras Spath, Torquatisphinctes Spath, and Pachysphinctes Dietrich). The original specimens of ' Perisphinctes' densestriatus Steuer, Paraulacosphinctes striolatus (Steuer), Paraulacosphinctes? mangaensis (Steuer), and Torquatisphinctes proximus (Steuer) are photographically refigured, and their types are designated. Type specimens are also designated for Euvirgalithacoceras malarguense (Spath) and Choicensisphinctes choicensis (Burckhardt). The genus Euvirgalithacoceras is used for the first time for lowermost Tithonian Andean forms, and Choicensisphinctes is suggested as a derivated genus.

  6. Response to Comment on "A Jurassic ornithischian dinosaur from Siberia with both feathers and scales".

    Science.gov (United States)

    Godefroit, Pascal; Sinitsa, Sofia M; Dhouailly, Danielle; Bolotsky, Yuri L; Sizov, Alexander V; McNamara, Maria E; Benton, Michael J; Spagna, Paul

    2014-10-24

    Lingham-Soliar questions our interpretation of integumentary structures in the Middle-Late Jurassic ornithischian dinosaur Kulindadromeus as feather-like appendages and alternatively proposes that the compound structures observed around the humerus and femur of Kulindadromeus are support fibers associated with badly degraded scales. We consider this hypothesis highly unlikely because of the taphonomy and morphology of the preserved structures.

  7. Battling Jurassic Park: From a Fascination with Violence toward Constructive Knowledge.

    Science.gov (United States)

    Cain, Beverlyn; Bohrer, Cynthia

    1997-01-01

    Studied preschool children's inability to distinguish fantasy from fact utilizing the case of the popular movie Jurassic Park and the subsequent false information children obtained about dinosaurs. Described attempts made by teachers to address the resultant aggressive behavior and false knowledge gained and replace it with constructive knowledge.…

  8. Palynology of uppermost Jurassic and lowermost Cretaceous strata in the Eastern Netherlands

    NARCIS (Netherlands)

    Burger, D.

    1965-01-01

    The present investigation is a systematical treatment of the sporomorphs from strata at the Jurassic-Cretaceous boundary in the eastern Netherlands Twente area, and an attempt to apply palynology to detailed stratigraphical study, by making use of quantitative pollen analyses. The rock samples used

  9. The potential of vertebrate microfossils for marine to non-marine correlation in the Late Jurassic

    Institute of Scientific and Technical Information of China (English)

    Detlev Thies; Alexander Mudroch; Susan Turner

    2007-01-01

    Fish (cartilaginous: elasmobranch and bony: osteichthyan actinopterygian) and reptile (crocodile) microfossils comprising scales and teeth have been examined from a series of limestone samples in the Upper Jurassic of France and Germany to gauge the possibilities of using them for correlation between fully marine and hypo- or hyper-saline (non-marine) deposits.

  10. 3D visualisation of a Jurassic oolitic system with GPR data, Isle of Portland (UK)

    DEFF Research Database (Denmark)

    Moreau, Julien; Hansen, Trine Lykke; Nielsen, Lars

    The Isle of Portland shows exposure of uppermost Jurassic oolitic carbonate all along its coast and within several inland quarries. The exposure quality is very high with a potential 3D control. The site has a potential to understand the 3D architecture and the sedimentary dynamic of an oolitic s...

  11. Strobilus organization in the enigmatic gymnosperm Bernettia inopinata from the Jurassic of Germany

    NARCIS (Netherlands)

    Kustatscher, E.; van Konijnenburg - van Cittert, J.H.A.; Bauer, K.; Krings, M.

    2016-01-01

    The enigmatic fossil Bernettia inopinata from Lower Jurassic strata of Upper Franconia, Germany, has been described as a leaf-like structure a leaf-like structure bearing a proximal cluster of densely spaced, pillow-like objects believed to represent ovules or ovule-containing units. The systematic

  12. New finds of stegosaur tracks from the Upper Jurassic Lourinhã formation, Portugal

    DEFF Research Database (Denmark)

    Mateus, Octavio; Milàn, Jesper; Romano, Michael

    2011-01-01

    Eleven new tracks from the Upper Jurassic of Portugal are described and attributed to the stegosaurian ichnogenus Deltapodus. One track exhibits exceptionally well−preserved impressions of skin on the plantar surface, showing the stegosaur foot to be covered by closely spaced skin tubercles of ca...

  13. Geochemical Characteristics of REE in Jurassic Coal of Yan'an Formation from Dongsheng Coalfield

    Institute of Scientific and Technical Information of China (English)

    赵峰华; 丛志远; 彭苏萍; 唐跃刚; 任德贻

    2002-01-01

    Concentrations of rare earth elements (REE) in Jurassic coal of YanAn Formation from Dongsheng coalfield located in the northeast of Ordos basin were determined by instrumental neutron activation analysis (INAA). Curves of distrib ution pattern of REE were drawn, and many geochemical parameters were calculated . The result shows that 1) The contents of REE in Jurassic coal with low ash an d sulfur are lower than those of Carboniferous and Permian coal from the Basin of North China; 2) Inside the Dongsheng coalfield, coal from the north has high er contents of REE than that form the south because the north is near the area of source rock which is the main supplier of REE, while the south is far away from the area of source rocks; 3) Although Jurassic coal in Dongsheng is the low-ash coal with less than 10%, the contents of REE are still proportional to ash yie ld of ash and SiO2 contents. 4) Although the Jurassic coal in Dongsheng were deposited in oxidative continental environment of river-lake, Eu depletion of RE E I n coal commonly exists, and positive abnormity of Ce dose not exist. This reflec ts the REE distribution pattern of REE in source rock of continental area; and 5) Compared with other rocks, coal shows extremely complexity of distribution pa ttern of REE, which is the result of continuous alteration and redistribution of matter in coal occurred in open basin system.

  14. Klukiopsis jurassica——A new Jurassic schizaeaceous fern from China

    Institute of Scientific and Technical Information of China (English)

    邓胜徽[1; 王仕俊[2

    2000-01-01

    A new Jurassic schizaeaceous fern Klukiopsis jurassica gen. et sp. nov. from Yima, Henan Province, China is described. The new fern is characterized by the abaxial sori arranged in two rows, apical and complete annulus and more than 800 smooth trilete spores in each sorus.

  15. The upper Jurassic-lower cretaceous siliciclastic system in the Morocco offshore - Prevenance, transport and deposition

    NARCIS (Netherlands)

    Bertotti, G.; Arantegui, A.; Charton, R.; Luber, T.; Redfern, J.

    2015-01-01

    The Morocco segment of the Central Atlantic passive continental margin experienced km-scale exhumation during the early post-rift (late Jurassic-Early Cretaceous). In the Meseta and the High Atlas this led to the development of a N-S trending ridge sourcing terrigenous sediments which were brought t

  16. Architecture of an Upper Jurassic barrier island sandstone reservoir, Danish Central Graben:

    DEFF Research Database (Denmark)

    Johannessen, Peter N.; Nielsen, Lars H.; Nielsen, Lars

    2010-01-01

    An unusually thick (c. 88 m), transgressive barrier island and shoreface sandstone succession characterizes the Upper Jurassic Heno Formation reservoir of the Freja oil field situated on the boundary of Denmark and Norway. The development and preservation of such thick transgressive barrier islan...... such that the island aggraded and even prograded seawards and became wider and longer due to the large surplus of sand....

  17. Battling Jurassic Park: From a Fascination with Violence toward Constructive Knowledge.

    Science.gov (United States)

    Cain, Beverlyn; Bohrer, Cynthia

    1997-01-01

    Studied preschool children's inability to distinguish fantasy from fact utilizing the case of the popular movie Jurassic Park and the subsequent false information children obtained about dinosaurs. Described attempts made by teachers to address the resultant aggressive behavior and false knowledge gained and replace it with constructive knowledge.…

  18. Sense-Making--a Case Study Using the Movie "Jurassic Park."

    Science.gov (United States)

    Murphy, Tony P.

    1996-01-01

    Introduces Sense-Making, an alternative methodology which allows an insight into a person's perception of reality. Interviews science teachers following a viewing of "Jurassic Park" to investigate the relationship of the movie to their ontological view of science, society, and self. (Author/MVL)

  19. New Isophlebioid Dragonflies from the Middle Jurassic of Inner Mongolia, China (Insecta: Odonata: Isophlebioptera:Campterophlebiidae)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Binglan; REN Dong; PANG Hong

    2008-01-01

    Three new species of fossil dragonflies assigned to Sinokaratawia Nel, Huang and Lin in family Campterophlebiidae, i.e. S. daohugouica sp. nov., S. magica sp. nov. and S. gloriosa sp. nov., and new materials of male S. prokopi Nel, Huang and Lin, 2007 are described from the Middle Jurassic of Daohugou, Inner Mongolia, China. An emended diagnosis of genus Sinokaratawia was proposed.

  20. Evolutionary and Ecological Sequelae of Mass Extinctions: Examples From the Continental Triassic-Jurassic Boundary

    Science.gov (United States)

    Olsen, P. E.; Whiteside, J. H.

    2003-12-01

    The Triassic-Jurassic boundary at ˜200 Ma marks one of the five major mass-extinctions of the Phanerozoic and, depending on the metrics used, was similar in magnitude to the K-T mass extinction. In continental environments about 50% of all tetrapod families are eliminated and although floral diversity change is difficult to gauge, a similar proportion of palynomorph taxa disappear at the boundary. The extinction event appears to have been very abrupt, followed by a roughly 900 ky super-greenhouse period characterized by increased precipitation. We hypothesize a series of biological consequences of the drop in diversity and associated super-greenhouse based on observations of the earliest Jurassic assemblages, largely from eastern North America. 1) The drop in diversity results in a collapse of ecological interactions that tend to stabilize the composition of regional biotas and buffer them from invading forms. Triassic assemblages show considerable biogeographic provinciality despite the existence of Pangea, but the earliest Jurassic assemblages were extraordinarily homogenous with many vertebrate genera being essentially global in distribution. 2) Initially the post-boundary terrestrial assemblages were comprised of eurytopic trophic generalists, with animal communities with few herbivores, but abundant carnivores and detritivores subsisting on aquatic-based food webs. The earliest Jurassic tetrapod footprint record is overwhelmingly dominated by the footprints of ceratosaurian theropod dinosaurs, the latter having skull characteristics usually associated at least in part with piscivory. 3) The dramatic size changes over very short periods of time were likely due to an absence of competition (i.e., ecological release). The maximum size of theropod dinosaur footprints increased by about 25% within 10 ky following the boundary, corresponding to a doubling of mass. 4) Representatives of clades with intrinsically high rates of speciation tend to form species flocks

  1. Jurassic extension and Cenozoic inversion tectonics in the Asturian Basin, NW Iberian Peninsula: 3D structural model and kinematic evolution

    Science.gov (United States)

    Uzkeda, Hodei; Bulnes, Mayte; Poblet, Josep; García-Ramos, José Carlos; Piñuela, Laura

    2016-09-01

    We constructed a geological map, a 3D model and cross-sections, carried out a structural analysis, determined the stress fields and tectonic transport vectors, restored a cross section and performed a subsidence analysis to unravel the kinematic evolution of the NE emerged portion of the Asturian Basin (NW Iberian Peninsula), where Jurassic rocks crop out. The major folds run NW-SE, normal faults exhibit three dominant orientations: NW-SE, NE-SW and E-W, and thrusts display E-W strikes. After Upper Triassic-Lower Jurassic thermal subsidence, Middle Jurassic doming occurred, accompanied by normal faulting, high heat flow and basin uplift, followed by Upper Jurassic high-rate basin subsidence. Another extensional event, possibly during Late Jurassic-Early Cretaceous, caused an increment in the normal faults displacement. A contractional event, probably of Cenozoic age, led to selective and irregularly distributed buttressing and fault reactivation as reverse or strike-slip faults, and folding and/or offset of some previous faults by new generation folds and thrusts. The Middle Jurassic event could be a precursor of the Bay of Biscay and North Atlantic opening that occurred from Late Jurassic to Early Cretaceous, whereas the Cenozoic event would be responsible for the Pyrenean and Cantabrian ranges and the partial closure of the Bay of Biscay.

  2. THANETIAN AND EARLY YPRESIAN ORTHOPHRAGMINES (FORAMINIFERA: DISCOCYCLINIDAE AND ORBITOCLYPEIDAE FROM THE CENTRAL WESTERN TETHYS (TURKEY, ITALY AND BULGARIA AND THEIR REVISED TAXONOMY AND BIOSTRATIGRAPHY

    Directory of Open Access Journals (Sweden)

    GYÖRGY LESS

    2007-11-01

    Full Text Available The rich orthophragminid assemblages from the upper Thanetian and lower Ypresian of Turkey are discussed together with the coeval faunas from Spilecco (N Italy and Beloslav (Bulgaria. Their taxonomy, evolution and biozonation in the Western Tethys are revised. Our biometric study is based mainly on a large number of equatorial sections of megalospheric individuals. We present the emended description of Discocyclina seunesi, D. tenuis, Orbitoclypeus multiplicatus, O. bayani and Asterocyclina taramellii. A new species, Nemkovella stockari is introduced. The evolutionary lineages of Discocyclina seunesi, Orbitoclypeus multiplicatus and O. bayani are restored for the first time by using the consistent size-increase of the megalospheric embryon that also allowed introducing some new subspecies (Discocyclina seunesi beloslavensis, D. s. karabuekensis, Orbitoclypeus multiplicatus kastamonuensis, O. bayani kurucasileensis and O. munieri ponticus. By owing the most complete record of Thanetian and early Ypresian orthophragmines from the Western Tethys (using also data from SW France and the Crimean Peninsula we could reconstruct their early evolution. The chronostratigraphical position of some localities was ascertained from planktic and larger benthic foraminifera, as well as calcareous nannoplankton. In the updated orthophragminid zonation (zones are marked by OZ, OZ 1a corresponds to the early Thanetian, OZ 1b to the middle Thanetian. They are distinguished on the base of the evolution of Discocyclina seunesi. In these zones, only two unribbed species of Discocyclina and Orbitoclypeus each are present. Ribbed Orbitoclypeus, genus Asterocyclina and Nemkovella appeared in the redefined OZ 2 zone belonging to the late Thanetian. Discocyclina archiaci and D. dispansa substituted D. seunesi at about the Paleocene/Eocene boundary. The early Ypresian can be subdivided into the OZ 3 and 4 zones that can be distinguished from each other by the different

  3. Basin geodynamics and sequence stratigraphy of Upper Triassic to Lower Jurassic deposits of Southern Tunisia

    Science.gov (United States)

    Carpentier, Cédric; Hadouth, Suhail; Bouaziz, Samir; Lathuilière, Bernard; Rubino, Jean-Loup

    2016-05-01

    Aims of this paper are to propose a geodynamic and sequential framework for the late Triassic and early Jurassic of and south Tunisia and to evidence the impact of local tectonics on the stratigraphic architecture. Facies of the Upper Triassic to Lower Jurassic of Southern Tunisia have been interpreted in terms of depositional environments. A sequential framework and correlation schemes are proposed for outcrops and subsurface transects. Nineteen middle frequency sequences inserted in three and a half low frequency transgression/regression cycles were evidenced. Despite some datation uncertainties and the unknown durations of Lower Jurassic cycles, middle frequency sequences appear to be controlled by eustasy. In contrast the tectonics acted as an important control on low frequency cycles. The Carnian flooding was certainly favored by the last stages of a rifting episode which started during the Permian. The regression accompanied by the formation of stacked angular unconformities and the deposition of lowstand deposits during the late Carnian and Norian occured during the uplift and tilting of the northern basin margins. The transpressional activity of the Jeffara fault system generated the uplift of the Tebaga of Medenine high from the late Carnian and led to the Rhaetian regional angular Sidi Stout Unconformity. Facies analysis and well-log correlations permitted to evidence that Rhaetian to Lower Jurassic Messaoudi dolomites correspond to brecciated dolomites present on the Sidi Stout unconformity in the North Dahar area. The Early-cimmerian compressional event is a possible origin for the global uplift of the northern African margin and Western Europe during the late Carnian and the Norian. During the Rhaetian and the early Jurassic a new episode of normal faulting occured during the third low frequency flooding. This tectonosedimentary evolution ranges within the general geodynamic framework of the north Gondwana margin controlled by the opening of both

  4. Trans-border (north-east Serbia/north-west Bulgaria correlations of the Jurassic lithostratigraphic units

    Directory of Open Access Journals (Sweden)

    Tchoumatchenco Platon

    2011-01-01

    Full Text Available Herein, correlations of the Jurassic sediments from NE Serbia with those of NW Bulgaria are made. The following Jurassic palaeogeographic units: the Eastern Getic, the Infra-Getic and the Moesian Platform are included in the study. The East Getic was studied in the outcrops near Rgotina, where the sedimentation started in the Hettangian and continued during the Callovian-Late Jurassic and is represented by platform carbonates. The Infra-Getic is documented by the sections of Dobra (Pesača and the allochtonous sediments near the Štubik. Very important for the Infra-Getic are the Late Jurassic volcano-sedimentary deposits of the Vratarnica Series, which crop out near Vratarnica Village. The Jurassic Moesian platform was studied in the sections near D. Milanovac and Novo Korito (Serbia and in their prolongation in NW Bulgaria into the Gornobelotintsi palaeograben. Very important are the correlation in the region of Vrška Čuka (Serbia and Vrashka Chuka (Bulgaria - Rabisha Village (Magura Cave. A revision of the Jurassic sediments on the Vidin palaeohorst, which were studied in the Belogradchik palaeohorst, Gorno-Belotintsi palaeograben, Belimel palaeohorst and the Mihaylovgrad palaeograben, is made. The sedimentation on the Vidin palaeohorst started during different parts of the Middle Jurassic, and in the Mihaylovgrad palaeograben during the Hettangian (Lower Jurassic where the sediments were deposited in relatively deeper water conditions. To south, the relatively shallow water sediments deposited on the Jurassic Vratsa palaeohorst on the southern board of the Mihaylovgrad palaeograben are described.

  5. Linking serpentinite geochemistry with tectonic evolution at the subduction plate-interface: The Voltri Massif case study (Ligurian Western Alps, Italy)

    Science.gov (United States)

    Cannaò, E.; Scambelluri, M.; Agostini, S.; Tonarini, S.; Godard, M.

    2016-10-01

    Recent geochemical work shows that subduction-zone serpentinites are repositories for fluid-mobile elements absorbed during interaction with sediment-derived fluids. Unraveling the geochemical fingerprint of these rocks helps to define timing of tectonic accretion of sediments along the subduction interface and the role of serpentinite in element recycling to volcanic arcs. Here we present the trace element and isotopic composition (B-O-H, Sr, Pb) of high-pressure serpentinites from the Voltri Massif (Ligurian Western Alps, Italy), to discuss their role as incompatible element carriers and their contribution to recycling of sediment-derived components in subduction zones. The serpentinites presented here record metamorphic olivine growth during eclogite-facies metamorphism and show undeformed and mylonitic textures. Field relations show that undeformed rocks are enclosed in deformed ones and that no metasedimentary rocks are present nearby. Undeformed serpentinite has very high δ11BSRM951 (from +26‰ to +30‰), low Sr and Pb isotope ratios (87Sr/86Sr = 0.7053-0.7069; 206Pb/204Pb = 18.131-18.205) and low As and Sb contents (0.1 and 0.01 μg/g, respectively). Oxygen and hydrogen isotope compositions are +4.5‰ and -67‰, respectively. In contrast, mylonitic serpentinite shows lower δ11B (from +22‰ to +17‰), significant enrichment in radiogenic Sr and Pb isotopes (87Sr/86Sr up to 0.7105; 206Pb/204Pb up to 18.725), and enrichment in As and Sb (1.3 and 0.39 μg/g, respectively). δ18O of the mylonitic serpentinites reaches values of +5.9‰, whereas δD is comparable with that of undeformed rocks (approximately -70‰). In mylonitic serpentinites, the B and Sr isotopic values and the fluid-mobile element (FME) concentrations are near those for the Voltri metasedimentary rocks (calc- and mica-schists). Pb systematics also reveal influx of a crust-derived component. Our dataset shows that undeformed serpentinite still preserves an oceanic geochemical fingerprint

  6. A taxonomic review of the Late Jurassic eucryptodiran turtles from the Jura Mountains (Switzerland and France

    Directory of Open Access Journals (Sweden)

    Jérémy Anquetin

    2014-05-01

    Full Text Available Background. Eucryptodiran turtles from the Late Jurassic (mainly Kimmeridgian deposits of the Jura Mountains (Switzerland and France are among the earliest named species traditionally referred to the Plesiochelyidae, Thalassemydidae, and Eurysternidae. As such, they are a reference for the study of Late Jurassic eucryptodires at the European scale. Fifteen species and four genera have been typified based on material from the Late Jurassic of the Jura Mountains. In the past 50 years, diverging taxonomic reassessments have been proposed for these turtles with little agreement in sight. In addition, there has been a shift of focus from shell to cranial anatomy in the past forty years, although most of these species are only represented by shell material. As a result, the taxonomic status of many of these 15 species remains ambiguous, which prevents comprehensive comparison of Late Jurassic turtle assemblages throughout Europe and hinders description of new discoveries, such as the new assemblage recently unearthed in the vicinity of Porrentruy, Switzerland.Methods. An exhaustive reassessment of the available material provides new insights into the comparative anatomy of these turtles. The taxonomic status of each of the 15 species typified based on material from the Late Jurassic of the Jura Mountains is evaluated. New diagnoses and general descriptions are provided for each valid taxon.Results. Six out of the 15 available species names are recognized as valid: Plesiochelys etalloni, Craspedochelys picteti, Craspedochelys jaccardi, Tropidemys langii, Thalassemys hugii, and ‘Thalassemys’ moseri. The intraspecific variability of the shell of P. etalloni is discussed based on a sample of about 30 relatively complete specimens from Solothurn, Switzerland. New characters are proposed to differentiate P. etalloni, C. picteti, and C. jaccardi, therefore rejecting the previously proposed synonymy of these forms. Based partly on previously undescribed

  7. Tango in the Mid-Jurassic: 10,000-Yr Geomagnetic Field Reversals

    Science.gov (United States)

    Steiner, M.

    2001-12-01

    A continuous magnetostratigraphic signature of Layer 2A from Jurassic Quiet Zone (JQZ) oceanic crust now is known from two separate paleo-magnetic data sets. Measurement/demagnetization along the length of the entire core at 5-cm intervals generated ~100,000 data points, whereas a suite of 472 discrete samples also were taken from throughout the core. Both data sets display the same magnetization pattern, a series of repeated sinusoidal inclination changes downhole. Six inter-vals of maximum inclination (three positive, three negative) are obser-ved. Maximum inclination intervals of +/-40° are separated by regions of smoothly varying intermediate inclination values. Despite lack of azmuithal orientation of the core, downhole magnetic logging (Larson et al., in prep.) shows full ~360° directional change in the magnetization vector. Therefore, the maximum inclination regions represent polarity intervals of the geomagnetic field, and six polarity intervals in stacked sequence are contained in the upper 400 m thickness of Layer 2A at this site. The time duration spanned by these six reversals was estimated from recent seismic studies of young ocean crustal construction on the East Pacific Rise (EPR). Estimates of completion of construction of Layer 2A within 1-3 km from the rise crest and typical EPR half-spreading rates of 5-8 cm/yr suggest that the studied 400 m of ocean crust represents 37,000-60,000 years. The fast construction of EPR crust implies that the Middle Jurassic geomagnetic field was reversing at a phenomenal rate of 5000-10,000 years. These data establish that the `quiet' signature in the oldest portion of the lineated magnetic anomaly patterns in the ocean crust is due to exceedingly rapid reversals of the geomagnetic field, because succes-sive, superposed opposite-polarity magnetic signatures will essentially cancel one another out at the sea surface. The width of the 'quiet' magnetic signature in the western Pacific Ocean implies that the 5000

  8. TRANSITION FROM CARBONATE PLATFORM TO PELAGIC DEPOSITION (MID JURASSIC- LATE CRETACEOUS, VOURINOS MASSIF, NORTHERN GREECE

    Directory of Open Access Journals (Sweden)

    NICOLAOS CARRAS

    2004-03-01

    Full Text Available A Jurassic- Cretaceous carbonate succession crops out along the Zyghosti Rema, Kozani (Northern Greece. The substratum consists of the ophiolitic succession of the Vourinos Massif (Pelagonian Domain: serpentinites tectonically overlain by basalts, with thin lenses of radiolarian cherts of middle Bathonian age. The contact with the overlying Jurassic limestones is tectonic. Eight informal units have been distinguished within the Mesozoic limestones, from the base upwards. (A bioclastic, intraclastic and oolitic packstone (Callovian- Oxfordian. (B bioclastic packstone and coral boundstone (Oxfordian . (C bioclastic and oncoidal wackestone with Clypeina jurassica (Oxfordian- Upper Kimmeridgian. (D (Upper Kimmeridgian- Portlandian: oncoidal packstone and rudstone (facies D1; intraclastic and bioclastic grainstone and packstone (facies D2; neptunian dykes with intraclastic and bioclastic wackestone and packstone filling (facies D3; neptunian dykes with Fe-Mn rich laterite filling and with pink silty filling of early Late Cretaceous age. An unconformity surface, due to emersion and erosion of the platform during the latest Jurassic- Early Cretaceous, is overlain by (E intraclastic, bioclastic packstone and grainstone (Cenomanian. (F massive body of debrites with coral, echinoderm, algae and rudist large clasts (facies F1 (Cenomanian; turbiditic beds of bioclastic, intraclastic and lithoclastic rudstone and grainstone (facies F2. (G thin bedded bioclastic mudstone and wackestone with planktonic foraminifers and radiolarians, alternating with turbiditic beds of bioclastic, intraclastic packstone and rudstone and with conglomeratic levels and slumped beds of the previous turbidites (upper Santonian- lower Campanian. (H: bioclastic packstone with planktonic foraminifers (facies H1 (lower Campanian - ?Maastrichtian; amalgamated turbiditic beds of bioclastic wackestone and packstone with planktonic foraminifers (facies H2; turbiditic beds of bioclastic

  9. The Jurassic of Denmark and Greenland: Late Triassic – Jurassic development of the Danish Basin and the Fennoscandian Border Zone, southern Scandinavia

    Directory of Open Access Journals (Sweden)

    Nielsen, Lars Henrik

    2003-10-01

    Full Text Available The continental to marine Upper Triassic – Jurassic succession of the Danish Basin and the Fennoscandian Border Zone is interpreted within a sequence stratigraphic framework, and the evolution of the depositional basin is discussed. The intracratonic Permian–Cenozoic Danish Basin was formed by Late Carboniferous – Early Permian crustal extension followed by subsidence governed primarily by thermal cooling and local faulting. The basin is separated from thestable Precambrian Baltic Shield by the Fennoscandian Border Zone, and is bounded by basement blocks of the Ringkøbing–Fyn High towards the south. In Late Triassic – Jurassic times, the basin was part of the epeiric shallow sea that covered most of northern Europe. The Upper Triassic – Jurassic basin-fill is subdivided into two tectono-stratigraphic units by a basinwide intra-Aalenian unconformity. The Norian – Lower Aalenian succession was formed under relative tectonic tranquillity and shows an overall layer-cake geometry, except for areas with local faults and salt movements.Deposition was initiated by a Norian transgression that led to shallow marine deposition and was accompanied by a gradual climatic change to more humid conditions. Extensive sheets of shoreface sand and associated paralic sediments were deposited during short-lived forced regressions in Rhaetian time. A stepwise deepening and development of fully marine conditions followed in the Hettangian – Early Sinemurian. Thick uniform basinwide mud blankets weredeposited on an open storm-influenced shelf, while sand was trapped at the basin margins. This depositional pattern continued until Late Toarcian – Early Aalenian times when the basin became restricted due to renewed uplift of the Ringkøbing–Fyn High. In Middle Aalenian – Bathonian times, the former basin area was subjected to deep erosion, and deposition became restricted to the fault-bounded Sorgenfrei–Tornquist Zone. Eventually the fault margins

  10. Paleomagnetism of Jurassic and Cretaceous rocks bounding the Santa Marta massif - NW corner of Colombia, South America

    Science.gov (United States)

    Bayona, G.; Jimenez, G.; Silva, C.

    2008-12-01

    The Santa Marta massif (SMM) is a complex terrain located in the NW margin of South America, bounded by the left-lateral Santa Marta fault to the west and the right-lateral Oca fault to the north. The SMM is cored by Precambrian metamorphic and Jurassic intrusive rocks, whereas along the SE flank crop out Jurassic volcanic rocks overlying unconformably by Limestones of Cretaceous age. Paleomagnetic analysis of 30 sites in the Jurassic and Cretaceous units in the SE region uncovered two principal magnetic components. The component "a", isolated in low coercivity and temperatures, has declinations to the north and moderate positive inclinations representing the actual field direction (n=11, D=347.6 I=23 K=30.77, a95=8.4). The component "c", with high coercivity and temperatures, has two orientations. After two-step tilt corrections, the first has northward declination and positive, low inclination (n=9, D=12, I=3, K=18.99, a95=12.1); this direction was uncovered in Cretaceous and some Jurassic rocks near to the Santa Marta fault, and we consider it as a Cretaceous component. The second direction was uncovered only in Jurassic rocks and has NNE declinations with negative-low inclinations (n=9, D=11.3 I=-14.3 K=12.36, a95=15.2); this direction represents a Jurassic component. Jurassic and Cretaceous directions isolated in areas faraway of the Santa Marta Fault suggest slight clockwise vertical-axes rotation. The Jurassic component suggests northward translation of the SMM from Paleolatitude -7.3, to near the magnetic equador in the Cretaceous, and to northern latitudes in the Cenozoic.

  11. A Remarkable New Family of Jurassic Insects (Neuroptera) with Primitive Wing Venation and Its Phylogenetic Position in Neuropterida

    OpenAIRE

    Qiang Yang; Vladimir N Makarkin; Winterton, Shaun L.; Khramov, Alexander V.; Dong Ren

    2012-01-01

    BACKGROUND: Lacewings (insect order Neuroptera), known in the fossil record since the Early Permian, were most diverse in the Mesozoic. A dramatic variety of forms ranged in that time from large butterfly-like Kalligrammatidae to minute two-winged Dipteromantispidae. PRINCIPAL FINDINGS: We describe the intriguing new neuropteran family Parakseneuridae fam. nov. with three new genera and 15 new species from the Middle Jurassic of Daohugou (Inner Mongolia, China) and the Early/Middle Jurassic o...

  12. Dinosaur tracks in Lower Jurassic coastal plain sediments (Sose Bugt Member, Rønne Formation) on Bornholm, Denmark

    DEFF Research Database (Denmark)

    Clemmensen, Lars B; Milàn, Jesper; Pedersen, Gunver K

    2014-01-01

    Fluvial palaeochannels of coastal plain sediments of the Lower Jurassic Sose Bugt Member of the Rønne Formation exposed in the coastal cliffs at Sose Bugt, Bornholm, contain abundant dinosaur or other large vertebrate tracks in the form of deformation structures exposed in vertical section...... track. Contemporary Upper Triassic – Lower Jurassic strata from southern Sweden and Poland contain a diverse track fauna, supporting our interpretation. This is the earliest evidence of dinosaur activity in Denmark....

  13. The first euthemistid damsel-dragonfly from the Middle Jurassic of China (Odonata, Epiproctophora, Isophlebioptera).

    Science.gov (United States)

    Li, Yongjun; Nel, André; Shih, Chungkun; Ren, Dong; Pang, Hong

    2013-01-01

    Sinoeuthemis daohugouensis gen. et sp. n. is the first record of the isophlebiopteran family Euthemistidae from Middle Jurassic of northeast China, while previously this family was restricted to the early Late Jurassic Kazakhstan. This new finding allows us to emend the family diagnosis with hindwing characters. This new species shows a mixture of characters alternatively present in different genera of the two families Euthemistidae and Sphenophlebiidae.

  14. Dinosaur evolution. A Jurassic ornithischian dinosaur from Siberia with both feathers and scales.

    Science.gov (United States)

    Godefroit, Pascal; Sinitsa, Sofia M; Dhouailly, Danielle; Bolotsky, Yuri L; Sizov, Alexander V; McNamara, Maria E; Benton, Michael J; Spagna, Paul

    2014-07-25

    Middle Jurassic to Early Cretaceous deposits from northeastern China have yielded varied theropod dinosaurs bearing feathers. Filamentous integumentary structures have also been described in ornithischian dinosaurs, but whether these filaments can be regarded as part of the evolutionary lineage toward feathers remains controversial. Here we describe a new basal neornithischian dinosaur from the Jurassic of Siberia with small scales around the distal hindlimb, larger imbricated scales around the tail, monofilaments around the head and the thorax, and more complex featherlike structures around the humerus, the femur, and the tibia. The discovery of these branched integumentary structures outside theropods suggests that featherlike structures coexisted with scales and were potentially widespread among the entire dinosaur clade; feathers may thus have been present in the earliest dinosaurs.

  15. An enigmatic plant-eating theropod from the Late Jurassic period of Chile.

    Science.gov (United States)

    Novas, Fernando E; Salgado, Leonardo; Suárez, Manuel; Agnolín, Federico L; Ezcurra, Martín D; Chimento, Nicolás R; de la Cruz, Rita; Isasi, Marcelo P; Vargas, Alexander O; Rubilar-Rogers, David

    2015-06-18

    Theropod dinosaurs were the dominant predators in most Mesozoic era terrestrial ecosystems. Early theropod evolution is currently interpreted as the diversification of various carnivorous and cursorial taxa, whereas the acquisition of herbivorism, together with the secondary loss of cursorial adaptations, occurred much later among advanced coelurosaurian theropods. A new, bizarre herbivorous basal tetanuran from the Upper Jurassic of Chile challenges this conception. The new dinosaur was discovered at Aysén, a fossil locality in the Upper Jurassic Toqui Formation of southern Chile (General Carrera Lake). The site yielded abundant and exquisitely preserved three-dimensional skeletons of small archosaurs. Several articulated individuals of Chilesaurus at different ontogenetic stages have been collected, as well as less abundant basal crocodyliforms, and fragmentary remains of sauropod dinosaurs (diplodocids and titanosaurians).

  16. Reduced plumage and flight ability of a new Jurassic paravian theropod from China.

    Science.gov (United States)

    Godefroit, Pascal; Demuynck, Helena; Dyke, Gareth; Hu, Dongyu; Escuillié, François; Claeys, Philippe

    2013-01-01

    Feathered theropods were diverse in the Early Cretaceous Jehol Group of western Liaoning Province, China. Recently, anatomically distinct feathered taxa have been discovered in the older Middle-Late Jurassic Tiaojishan Formation in the same region. Phylogenetic hypotheses including these specimens have challenged the pivotal position of Archaeopteryx in bird phylogeny. Here we report a basal troodontid from the Tiaojishan Formation that resembles Anchiornis, also from Jianchang County (regarded as sister-taxa). The feathers of Eosinopteryx are less extensive on the limbs and tail than Anchiornis and other deinonychosaurians. With reduced plumage and short uncurved pedal claws, Eosinopteryx would have been able to run unimpeded (with large foot remiges cursorial locomotion was likely problematic for Anchiornis). Eosinopteryx increases the known diversity of small-bodied dinosaurs in the Jurassic, shows that taxa with similar body plans could occupy different niches in the same ecosystem and suggests a more complex picture for the origin of flight.

  17. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers.

    Science.gov (United States)

    Zhang, Fucheng; Zhou, Zhonghe; Xu, Xing; Wang, Xiaolin; Sullivan, Corwin

    2008-10-23

    Recent coelurosaurian discoveries have greatly enriched our knowledge of the transition from dinosaurs to birds, but all reported taxa close to this transition are from relatively well known coelurosaurian groups. Here we report a new basal avialan, Epidexipteryx hui gen. et sp. nov., from the Middle to Late Jurassic of Inner Mongolia, China. This new species is characterized by an unexpected combination of characters seen in several different theropod groups, particularly the Oviraptorosauria. Phylogenetic analysis shows it to be the sister taxon to Epidendrosaurus, forming a new clade at the base of Avialae. Epidexipteryx also possesses two pairs of elongate ribbon-like tail feathers, and its limbs lack contour feathers for flight. This finding shows that a member of the avialan lineage experimented with integumentary ornamentation as early as the Middle to Late Jurassic, and provides further evidence relating to this aspect of the transition from non-avian theropods to birds.

  18. Oxfordian-Kimmeridgian (Late Jurassic) reservoir sandstones in the Witch Ground Graben, U. K. North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Harker, S.D. (Occidental Petroleum (Caledonia) Ltd., Aberdeen (United Kingdom)); Mantel, K.A. (Narwhal, London (United Kingdom)); Morton, D.J. (Deminex U.K. Oil and Gas Ltd., London (United Kingdom)); Riley, L.A. (Paleoservices, Watford (United Kingdom))

    1991-03-01

    Oil-bearing Late Jurassic Oxfordian-Kimmeridgian sandstones of the Sgiath and Piper formations are of major economic importance in the Witch Ground Graben. They form the reservoirs in Scott, which in 1993 will be the largest producing North Sea oil field to come on stream for more than a decade. Together with Scott, the Piper, Saltire, Tartan, Highlander, Petronella, Rob Roy, and Ivanhoe fields contained almost 2 Bbbl of recoverable reserves in these formations. The Sgiath and Piper represent two phases of Late Jurassic transgression and regression, initially represented by paralic deposited sand culminating in a wave-dominated delta sequence. The history of the Sgiath and Piper formations is reviewed and lithostratigraphic and biostratigraphic correlations presented to illustrate the distribution of the reservoir sandstones.

  19. The oldest haplogyne spider (Araneae: Plectreuridae), from the Middle Jurassic of China

    Science.gov (United States)

    Selden, Paul A.; Huang, Diying

    2010-05-01

    New fossil spiders (Arachnida: Araneae) from Middle Jurassic (ca. 165 Ma) strata of Daohugou, Inner Mongolia, China are described as Eoplectreurys gertschi gen. et sp. nov. and referred to the modern haplogyne family Plectreuridae. This small family is restricted to southwestern USA, Mexico, and the adjacent Caribbean area today and hitherto has only a sparse Cenozoic fossil record. The morphology of Eoplectreurys is remarkably similar to modern forms and thus demonstrates great evolutionary conservatism. This new discovery not only extends the fossil record of the family by at least 120 Ma to the Middle Jurassic but also supports the hypothesis of a different distribution of the family in the past than today and subsequent extinction over much of its former range.

  20. Uppermost Jurassic-Lower Cretaceous carbonate deposits from Fara San Martino (Maiella, Italy: biostratigraphic remarks

    Directory of Open Access Journals (Sweden)

    Roberta Bruni

    2007-10-01

    Full Text Available The Uppermost Jurassic-Lower Cretaceous limestone succession in the Maiella region of Italy has been investigated in a profile covering more than 400 m stratigraphical thickness at Fara San Martino. The succession mainly consists of peritidal limestones, intertidal and supratidal sequences being dominant, together with subtidal lagoonal facies. As a consequence, the microfossil assemblages are generally poorly developed, Microfossils occur within the subtidal lagoonal facies of this suite of restricted sediments. This feature led us to recognise five informal biostratigraphic intervals, which are facies related – instead of biozones, each of the intervals being characterized by specific micropaleontological associations. The occurrence and/or disappearance of some marker microfossils were used as references for separating these intervals. Based on these markers, the Uppermost Jurassic-Lower Cretaceous carbonate deposits from Maiella region may be correlated with similar deposits from the Apennines and from other regions in the perimediterranean area.

  1. The Requel: Between the Remake and the Sequel. Jurassic World as a Case Study Analysis

    Directory of Open Access Journals (Sweden)

    Irene RAYA BRAVO

    2017-06-01

    Full Text Available In the audiovisual field, the expansion of the stories is, specifically, materialized through remakes, adaptations and franchises. In this context, the remakes or new versions are recurrent formulas because they recover familiar contents for audiences and, at the same time, they reinvent it in order to capture new generations’ attention. Nevertheless, the remake formula has been changing in the new millennium, adapting to new narrative trends. In recent years, because of the rise of intertextuality and the increasing value of nostalgia, many films have been produced halfway between the remake and the sequel, such as Star Wars. Episode VII: The Force Awakens or Terminator Genisys. In particular, the aim of this paper is to make a comparative analysis between Jurassic Park and Jurassic World because, although this last film extends the original discourse as a sequel, it also offers a reinterpretation of the first film.

  2. New evidence of shared dinosaur across Upper Jurassic Proto-North Atlantic: Stegosaurus from Portugal

    Science.gov (United States)

    Escaso, Fernando; Ortega, Francisco; Dantas, Pedro; Malafaia, Elisabete; Pimentel, Nuno L.; Pereda-Suberbiola, Xabier; Sanz, José Luis; Kullberg, José Carlos; Kullberg, María Carla; Barriga, Fernando

    2007-05-01

    More than one century after its original description by Marsh in 1877, we report in this paper the first uncontroversial evidence of a member of the genus Stegosaurus out of North America. The specimen consists of a partial skeleton from the Upper Jurassic of Portugal, herein considered as Stegosaurus cf. ungulatus. The presence of this plated dinosaur in the upper Kimmeridgian-lower Tithonian Portuguese record and synchronic levels of the Morrison Formation of North America reinforces previous hypothesis of a close relationship between these two areas during the Late Jurassic. This relationship is also supported by geotectonic evidences indicating high probability of an episodic corridor between the Newfoundland and Iberian landmasses. Together, Portuguese Stegosaurus discovery and geotectonic inferences could provide a scenario with episodical faunal contact among North Atlantic landmasses during the uppermost Kimmeridgian-lowermost Tithonian (ca. 148-153 Ma ago).

  3. Paleogeography of the northern portion of the Mixteca terrain, southern Mexico, during the Middle Jurassic

    Science.gov (United States)

    Caballero-Miranda, C.; Morán-Zenteno, D. J.; Urrutia-Fucugauchi, J.; Silva-Romo, G.; Böhnel, H.; Jurado-Chichay, Z.; Cabral-Cano, E.

    A preliminary paleogeographic reconstruction of the northern Mixteca terrain in southern Mexico is presented for the Middle Jurassic. The reconstruction is derived from combined analyses of spatial distribution of marine-continental Jurassic sedimentary units, identification of sediment source, and observations based on sedimentary indicators of environment and transport directions, as well as paleomagnetic and anisotropy of magnetic susceptibility (AMS) results. There is an overall agreement between the AMS magnetic fabric results and the sedimentary indicators of current directions and paleogeographic elements. The results suggest a coastline at the south-southwest portion of this terrain, a general transport of fluvial sediments to the south and southwest, and marine influxes from the south. A Pacific margin provenance is supported by the paleomagnetic results for the northern portion of the Mixteca terrain.

  4. New fossil record of a Jurassic pterosaur from Neuquen Basin, Vaca Muerta Formation, Argentina

    Science.gov (United States)

    Codorniú, Laura; Garrido, Alberto

    2013-12-01

    Discoveries of Jurassic pterosaurs in the Southern Hemisphere are extremely unusual. In Argentina, pterosaurs from the Upper Jurassic (Tithonian) have only been found in the Northwest of Patagonia (Neuquén Basin). These come from marine deposits and three specimens have been discovered up to the present. In this paper, we report a new finding from the Neuquén Basin. This material is identified as a tibiotarsus, which probably belonged to an osteologically adult individual and represents a new species of a pterodactyloid pterosaur of medium size. This discovery provides new evidence that at least two different species of pterodactyloid pterosaurs may have coexisted in Los Catutos Member, Vaca Muerta Formation, from the shallow marine deposits of the Neuquén Basin.

  5. The oldest known snakes from the Middle Jurassic-Lower Cretaceous provide insights on snake evolution.

    Science.gov (United States)

    Caldwell, Michael W; Nydam, Randall L; Palci, Alessandro; Apesteguía, Sebastián

    2015-01-27

    The previous oldest known fossil snakes date from ~100 million year old sediments (Upper Cretaceous) and are both morphologically and phylogenetically diverse, indicating that snakes underwent a much earlier origin and adaptive radiation. We report here on snake fossils that extend the record backwards in time by an additional ~70 million years (Middle Jurassic-Lower Cretaceous). These ancient snakes share features with fossil and modern snakes (for example, recurved teeth with labial and lingual carinae, long toothed suborbital ramus of maxillae) and with lizards (for example, pronounced subdental shelf/gutter). The paleobiogeography of these early snakes is diverse and complex, suggesting that snakes had undergone habitat differentiation and geographic radiation by the mid-Jurassic. Phylogenetic analysis of squamates recovers these early snakes in a basal polytomy with other fossil and modern snakes, where Najash rionegrina is sister to this clade. Ingroup analysis finds them in a basal position to all other snakes including Najash.

  6. A previously unrecognized group of Middle Jurassic triconodontan mammals from Central Asia

    Science.gov (United States)

    Martin, Thomas; Averianov, Alexander O.

    2007-01-01

    Ferganodon narynensis gen. et sp. nov. is represented by a lower molariform tooth from the Middle Jurassic (Callovian) Balabansai Svita in Kyrgyzstan. The new genus is allied with Klamelia zhaopengi Chow and Rich 1984 from the Middle Jurassic Shishugou Formation in Xinjiang, northwest China to the new family Klameliidae based on parallelogram-shaped lower molariforms, imbricating rather than interlocking of cusps e- d- f, by a peculiar distolabial cingulid cusp, and by vertical folding of the enamel on the labial crown side. The new family Klameliidae fam. nov. is most similar to Gobiconodontidae by the structure of the molariform teeth and represents a previously unrecognized radiation of eutriconodontan mammals possibly endemic to Central Asia.

  7. Natural Gas Resource in Jurassic, Y Faulted Subbasin of Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    Yang Haibo; Hu Yutao; Wei Xinghua

    2000-01-01

    Y faulted depression is located in the southeast of Songliao basin, which is another important area explored for natural gas in deep Formation after Xujiaweizi. But it is lowly explored and is not likely to make a major breakthrough in nature gas exploration for shallow and medium layers. The data on the geochemistry and geology indicate that the deep source rocks, especially the Jurassic mudstone bas great potentials of natural gas generation. Based on this, the paper examines the conditions of natural gas generation and further points out the favorable prospective gas - bearing area. The results show that the amount of natural gas generated from the Jurassic mudstone in the Y faulted depression is 8.42 × 1012m3 and the favorable gas - generating area is the body of the faulted depression.

  8. 东北亚地区晚侏罗—白垩纪构造格架主体特点%Main Characteristics of Late Jurassic-Cretaceous Tectonic Framework in Northeast Asia

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Placing the main structural features of the Northeast China into Northeast Asia area, to analyze the tectonic setting, the Northeast Asia Late Mesozoic - Paleogene tectonic evolution can be divided into three periods: 1) the Middle -Late Jurassic, extension of the Tethys Ocean and the collision between North America and ancient Eurasia continental plate, resulting in Mongolia-Okhotsk Gulf closure and the formation of large-scale deep-level thrust in Mongolia and the North China block, and a long-range stacking effect in southern Mongolia and the northern margin of the North China block. 2) Late Jurassic - Early Cretaceous, the combined effects of Tethys Ocean, the Eurasian continental plate and the Paleo-Pacific tectonic domain (including the old Pacific or Izanaqi plate) .resulted in continental crust creeping eastward, stretching and block breaking activities, which were, accompanied by development of a small rift basin group and metamorphic core complexes. 3) Early Cretaceous (Late Albian)- Neogene (Miocene), the combined effects of the tectonic domain between Tethys (later including the Indian plate), the Pacific tectonic domain (including Izanaqi plate) and Eurasia continental plate resulted in Izanaqi ocean disappeared, the collision between the Okhotsk Oceanic micro-plate and the Eurasian continent, and the formations of the Eurasian continental margin volcanic belt and the depression basin on the continental margin. During 100 - 60 Ma, the interaction between the Pacific tectonic domain (including Izanaqi plate) and the Eurasian continent, had a major influence on the eastern edge of the Eurasian continent and caused continental lithospheric-crust thinning, the change of mantle type and a strong deep magmatic activity. Meanwhile, producing a series of the surface block effects related to the continental margin faulted block activities.%将东北地区主体构造特征置于东北亚大地构造背景中进行分析,可将东北亚地区晚中生代—古

  9. Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean

    Science.gov (United States)

    Zhang, Li-Yun; Ding, Lin; Pullen, Alex; Xu, Qiang; Liu, De-Liang; Cai, Fu-Long; Yue, Ya-Hui; Lai, Qing-Zhou; Shi, Ren-Deng; Ducea, Mihai N.; Kapp, Paul; Chapman, Alan

    2014-03-01

    A geologic investigation was undertaken in the Hoh-Xil-Songpan-Ganzi (HXSG) complex, northern Tibet in order to better understand magma genesis and evolution during the late stages of Paleo-Tethys ocean closure. The HXSG complex is composed of vast accumulations of Middle-Upper Triassic marine gravity flow deposits that were extensively intruded by igneous rocks. These early Mesozoic rocks exposed in this area record a rich history of accretionary tectonics during the amalgamation of the Tibetan Plateau terranes. Eight plutons sampled from the western HXSG complex yield zircon U-Pb ages that range from 225 to 193 Ma. Muscovite 40Ar/39Ar ages for the Hudongliang and Zhuonai Lake plutons yield ages of 210.7 ± 2.5 Ma and 212.7 ± 2.5 Ma, respectively. These plutonic rocks can be subdivided into two geochemically distinct groups. Group 1 (221-212 Ma: Dapeng Lake, Changhong Lake and Heishibei Lake plutons) is composed of high-K calc-alkaline rocks that have strongly fractionated REE patterns with high (La/Yb)N ratios (91-18) and generally lack Eu anomalies (Eu*/Eu = 1.02-0.68). Rocks in Group 1 display pronounced negative Nb-Ta and Ti anomalies on primitive mantle-normalized spidergrams. Group 1 rocks exhibit high Sr (782-240 ppm) and low Y (6.3-16.0 ppm) contents with high Sr/Y ratios (84-20). Based on Sr-Nd-Hf isotopic data (87Sr/86Sri = 0.7079-0.7090, ɛNd(t) = - 7.7-- 4.7, ɛHf(t) = - 5.7-- 0.8) and low MgO contents (MgO = 1.10-2.18%), Group 1 rocks are geochemically similar to adakitic rocks and were probably derived from partial melting of the downgoing Paleo-Tethys oceanic slab and overlying marine sediments. Group 2 plutons (225-193 Ma: Daheishan, Yunwuling, Zhuonai Lake, Malanshan and Hudongliang plutons) display lower P2O5 with increasing SiO2 and are medium-K to high-K I-type calc-alkaline bodies with low Sr (14-549 ppm) and high Y (22.3-10.5 ppm) contents. Group 2 rocks have variable fractionated REE patterns ((La/Yb)N = 3-38) and negative Eu anomalies (Eu

  10. Petrogenesis of late Paleozoic-to-early Mesozoic granitoids and metagabbroic rocks of the Tengchong Block, SW China: implications for the evolution of the eastern Paleo-Tethys

    Science.gov (United States)

    Zhu, Ren-Zhi; Lai, Shao-Cong; Qin, Jiang-Feng; Zhao, Shao-Wei

    2017-06-01

    This paper presents precise zircon U-Pb, bulk-rock geochemical, and Sr-Nd-Pb isotopic data for metagabbro, quartz diorite, and granite units within the Tengchong Block of SW China, which forms the southeastern extension of the Himalayan orogeny and the southwestern section of the Sanjiang orogenic belt, a key region for furthering our understanding of the evolution of the eastern Paleo-Tethys. These data reveal four groups of zircon U-Pb ages that range from the late Paleozoic to the early Mesozoic, including a 263.6 ± 3.6 Ma quartz diorite, a 218.5 ± 5.4 Ma two-mica granite, a 205.7 ± 3.1 Ma metagabbroic unit, and a 195.5 ± 2.2 Ma biotite granite. The quartz diorite in this area contains low concentrations of SiO2 (60.71-64.32 wt%), is sodium-rich, and is metaluminous, indicating formation from magmas generated by a mixed source of metamafic rocks with a significant metapelitic sedimentary material within lower arc crust. The two-mica granites contain high concentrations of SiO2 (73.2-74.3 wt%), are strongly peraluminous, and have evolved Sr-Nd-Pb isotopic compositions, all of which are indicative of a crustal source, most probably from the partial melting of felsic pelite and metagreywacke/psammite material. The metagabbros contain low concentrations of SiO2 (50.17-50.96 wt%), are sodium-rich, contain high concentrations of Fe2O3T (9.79-10.06 wt%) and CaO (6.88-7.12 wt%), and are significantly enriched in the Sr (869-894 ppm) and LREE (198.14-464.60 ppm), indicative of derivation from magmas generated by a metasomatized mantle wedge modified by the sedimentary-derived component. The biotite granites are weakly peraluminous and formed from magmas generated by melting of metasedimentary sources dominated by metagreywacke/psammite material. Combining the petrology and geochemistry of these units with the regional geology of the Indosinian orogenic belt provides evidence for two stages of magmatism: an initial stage that generated magmas during partial melting of

  11. ENVIRONMENTS AND FAUNAL PATTERNS IN THE KACHCHH RIFT BASIN, WESTERN INDIA, DURING THE JURASSIC

    OpenAIRE

    FRANZ THEODOR FÜRSICH; Callomon, John H.; DHIRENDRA K. PANDEY; ANAND K. JAITLY

    2004-01-01

    Marine Jurassic sediments (Bajocian-Tithonian) of the Kachchh Basin were deposited in a ramp setting. Except during the Middle and Late Bathonian, when a carbonate regime became established, the fill of the basin consists predominantly of siliciclastics. The sediments represent environments that range from coastal plains (rivers and associated flood plains with caliche nodules), deltas, brackish water lagoons, nearshore sand and iron-oolite bars of the inner ramp, generally situated above fai...

  12. Uppermost Jurassic-lower cretaceous radiolarian chert from the Tanimbar Islands (Banda Arc), Indonesia

    Science.gov (United States)

    Jasin, Basir; Haile, Neville

    This paper describes and figures Mesozoic Radiolaria from cherts in Pulau Ungar, Tanimbar Islands, eastern Indonesia. Two assemblages of Radiolaria are recognised. The lower assemblage is indicative of upper Tithonian (uppermost Jurassic) to Berriasian (lowermost Cretaceous) and the upper assemblage is of upper Valanginian to Barremian age. These are the first precise ages obtained from the Ungar Formation, a unit including sandstones with apparently good petroleum reservoir characteristics.

  13. A golden orb-weaver spider (Araneae: Nephilidae: Nephila) from the Middle Jurassic of China

    OpenAIRE

    Paul A Selden; Shih, Chungkun; Ren, Dong

    2011-01-01

    Nephila are large, conspicuous weavers of orb webs composed of golden silk, in tropical and subtropical regions. Nephilids have a sparse fossil record, the oldest described hitherto being Cretaraneus vilaltae from the Cretaceous of Spain. Five species from Neogene Dominican amber and one from the Eocene of Florissant, CO, USA, have been referred to the extant genus Nephila. Here, we report the largest known fossil spider, Nephila jurassica sp. nov., from Middle Jurassic (approx. 165 Ma) strat...

  14. Dynamic Paleogeography of the Jurassic Andean Basin: pattern of regression and general considerations on main features

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    J-C. Vicente

    2006-09-01

    Full Text Available Following examination of the evolution of the Jurassic Andean retroarc basin at a global scale for the Central Andes, this paper analyses the pattern of the regressive process, and discusses some general features concerning Andean Jurassic Paleogeography. The early Upper Jurassic regression obeys to an exactly reverse pattern as the one evidenced for the Lower Jurassic transgressive process. Sectors with late transgressions become those with early regressions while those with early transgressions show later regressions. This fact may indicate that the Norte Chico Isthmus (29°S to 30°30'S was a precociously emerged zone from the Bajocian. This carries again a split up between the Tarapacá and Aconcagua-Neuquén basins until their complete drying up in the Late Oxfordian following their restricted circulation. This evaporitic late stage presents great analogy with the Mediterranean «Messinian crisis» and gives evidence of a general tectonic and magmatic control on the straits. The local transgressions observed on the cratonic margin of the central part of these shrinking basins were due to shifting of water masses resulting from the regressive process on the northern and southern margins. Comparison between the main stages of transgression and regression allows some quantification concerning velocities of displacement of coastlines, specifically lengthwise. The permanence of paleogeographic and structural features over the time argues for an indisputable tectonic heritage. In the dynamic framework of this typical barred retroarc basin where arc magmatic activity has contributed considerably to variation on sediment supply and changing bathymetry of the seaways connecting with the Pacific Ocean, evidence for an assumed global eustatic cycle remains questionable or very subordinated.

  15. Jurassic Tectonic Revolution in China and New Interpretation of the "Yanshan Movement"

    Institute of Scientific and Technical Information of China (English)

    DONG Shuwen; ZHANG Yueqiao; LONG Changxing; YANG Zhenyu; JI Qiang; WANG Tao; HU Jianming; CHEN Xuanhua

    2008-01-01

    With acquisition and accumulation of new data of structural geological investigations and high-resolution isotopic dating data, we have greatly improved our understanding of the tectonic events occurring in eastern China during the period from the Late Jurassic to Early Cretaceous and may give a new interpretation of the nature, timing and geodynamic settings of the "Yanshan Movement". During the Mid-Late Jurassic (165±5 Ma), great readjustment of plate amalgamation kinematics took place in East Asia and the tectonic regime underwent great transformation, thus initiating a new tectonic regime in which the North China Block was the center and different plates converged toward it from the north, east and southwest and forming the "East Asia convergent"tectonic system characterized by intracontinental subduction and orogeny. As a consequence, the crustal lithosphere of the East Asian continent thickened considerably during the Late Jurassic,followed immediately by Early Cretaceous substantial lithospheric thinning and craton destruction featured by drastic lithospheric extension and widespread volcano-magmatic activities, resulting in a major biotic turnover from the Yanliao biota to Jehol Biota. Such a tremendous tectonic event that took place in the continent of China and East Asia is the basic connotation of the "Yanshan Movement". In the paper, according to the deformation patterns, geodynamic settings and deep processes, the "Yanshan Movement" is redefined as the Late Jurassic East Asian multi-directional plate convergent tectonic regime and its associated extensive intracontinental orogeny and great tectonic change that started at ~165±5 Ma. The substantial lithospheric attenuation in East China is considered the post-effect of the Yanshanian intracontinental orogeny and deformation.

  16. THE PROTECTION OF JURASSIC SITES AND FOSSILS: CHALLENGES FOR GLOBAL JURASSIC SCIENCE (INCLUDING A PROPOSED STATEMENT ON THE CONSERVATION OF PALAEONTOLOGICAL HERITAGE AND STRATOTYPES

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    KEVIN N. PAGE

    2004-03-01

    Full Text Available Effective geoconservation systems are crucial to the activities of subcommissions of the International Subcommission on Stratigraphy, such as the Jurassic Subcommission (ISJS. Fundamentally, the core activity of any Subcommission, the establishment of Global Stratotype Sections and Points (GSSPs is a conservation activity in itself, involving the selection of key sites, to be maintained as references for subsequent consultation. Without adequate national site protection and management systems this fundamental function is liable to fail as the selected site remains vulnerable to loss and damage. In addition, strict conservation systems applied without adequate understanding of the needs of research and education can also prevent or significantly inhibit geological science and the use of sites such as GSSPs. To address these extreme scenarios and assist the development of a more scientific approach to conservation of geological sites of stratigraphical and palaeontological importance during dialogues with administrative authorities, a Statement defining categories of palaeontological heritage requiring protection and the basic requirements needed to achieve the conservation of stratotype localities is here proposed. The context of the protection of Jurassic sites within other international projects is also reviewed, in particular the IUGS Geosites project, within which all GSSPs will be listed.

  17. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers

    Science.gov (United States)

    Lefèvre, Ulysse; Cau, Andrea; Cincotta, Aude; Hu, Dongyu; Chinsamy, Anusuya; Escuillié, François; Godefroit, Pascal

    2017-10-01

    Genuine fossils with exquisitely preserved plumage from the Late Jurassic and Early Cretaceous of northeastern China have recently revealed that bird-like theropod dinosaurs had long pennaceous feathers along their hindlimbs and may have used their four wings to glide or fly. Thus, it has been postulated that early bird flight might initially have involved four wings (Xu et al. Nature 421:335-340, 2003; Hu et al. Nature 461:640-643, 2009; Han et al. Nat Commun 5:4382, 2014). Here, we describe Serikornis sungei gen. et sp. nov., a new feathered theropod from the Tiaojishan Fm (Late Jurassic) of Liaoning Province, China. Its skeletal morphology suggests a ground-dwelling ecology with no flying adaptations. Our phylogenetic analysis places Serikornis, together with other Late Jurassic paravians from China, as a basal paravians, outside the Eumaniraptora clade. The tail of Serikornis is covered proximally by filaments and distally by slender rectrices. Thin symmetrical remiges lacking barbules are attached along its forelimbs and elongate hindlimb feathers extend up to its toes, suggesting that hindlimb remiges evolved in ground-dwelling maniraptorans before being co-opted to an arboreal lifestyle or flight.

  18. Storms and tsunamis: evidence of event sedimentation in the Late Jurassic Tendaguru Beds of southeastern Tanzania

    Science.gov (United States)

    Bussert, Robert; Aberhan, Martin

    2004-06-01

    In Late Jurassic shallow marine siliciclastic sediments of the dinosaur-bearing Tendaguru Beds from the Mandawa Basin of southeastern Tanzania we identified several event deposits. Based on an analysis of their sedimentological and palaeontological features, a storm-induced origin can be assumed for the majority of these deposits. This interpretation is in agreement with the regional palaeogeography and palaeoclimatological data, and is further supported by the widespread evidence of Late Jurassic storm-controlled sedimentation in adjacent basins along the East African margin. A particularly striking feature is a laterally extensive, conglomeratic bed with gravel components up to 30 cm in diameter, and megaripples indicating southward transport directions. The troughs between ripples are filled by cross-bedded fine-grained sandstones and siltsones with inferred transport directions to the north. Giant bedforms, a mixture of clasts of marine and continental origin, and evidence of opposite current directions suggest that this chaotically deposited sediment may have formed from a tsunami. Within the available time resolution this event is synchronous with the Morokweng impact structure in South Africa. However, because of the considerable distance of Morokweng from the Jurassic sea, direct links between both events cannot be established. Alternative mechanisms such as a landslide-generated tsunami are plausible, but not yet supported by geophysical data.

  19. A new Basal sauropodomorph dinosaur from the Lower Jurassic Navajo sandstone of Southern Utah.

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    Joseph J W Sertich

    Full Text Available BACKGROUND: Basal sauropodomorphs, or 'prosauropods,' are a globally widespread paraphyletic assemblage of terrestrial herbivorous dinosaurs from the Late Triassic and Early Jurassic. In contrast to several other landmasses, the North American record of sauropodomorphs during this time interval remains sparse, limited to Early Jurassic occurrences of a single well-known taxon from eastern North America and several fragmentary specimens from western North America. METHODOLOGY/PRINCIPAL FINDINGS: On the basis of a partial skeleton, we describe here a new basal sauropodomorph dinosaur from the Lower Jurassic Navajo Sandstone of southern Utah, Seitaad ruessi gen. et sp. nov. The partially articulated skeleton of Seitaad was likely buried post-mortem in the base of a collapsed dune foreset. The new taxon is characterized by a plate-like medial process of the scapula, a prominent proximal expansion of the deltopectoral crest of the humerus, a strongly inclined distal articular surface of the radius, and a proximally and laterally hypertrophied proximal metacarpal I. CONCLUSIONS/SIGNIFICANCE: Phylogenetic analysis recovers Seitaad as a derived basal sauropodomorph closely related to plateosaurid or massospondylid 'prosauropods' and its presence in western North America is not unexpected for a member of this highly cosmopolitan clade. This occurrence represents one of the most complete vertebrate body fossil specimens yet recovered from the Navajo Sandstone and one of the few basal sauropodomorph taxa currently known from North America.

  20. Discovery of a short-necked sauropod dinosaur from the Late Jurassic period of Patagonia.

    Science.gov (United States)

    Rauhut, Oliver W M; Remes, Kristian; Fechner, Regina; Cladera, Gerardo; Puerta, Pablo

    2005-06-01

    Sauropod dinosaurs are one of the most conspicuous groups of Mesozoic terrestrial vertebrates. They show general trends towards an overall increase in size and elongation of the neck, by means of considerable elongation of the length of individual vertebrae and a cervical vertebra count that, in some cases, increases to 19 (ref. 1). The long neck is a particular hallmark of sauropod dinosaurs and is usually regarded as a key feeding adaptation. Here we describe a new dicraeosaurid sauropod, from the latest Jurassic period of Patagonia, that has a particularly short neck. With a neck that is about 40% shorter than in other known dicraeosaurs, this taxon demonstrates a trend opposite to that seen in most sauropods and indicates that the ecology of dicraeosaurids might have differed considerably from that of other sauropods. The new taxon indicates that there was a rapid radiation and dispersal of dicraeosaurids in the Late Jurassic of the Southern Hemisphere, after the separation of Gondwana from the northern continents by the late Middle Jurassic.

  1. Timing, duration, and causes for Late Jurassic-Early Cretaceous anoxia in the Barents Sea

    Science.gov (United States)

    Georgiev, Svetoslav V.; Stein, Holly J.; Hannah, Judith L.; Xu, Guangping; Bingen, Bernard; Weiss, Hermann M.

    2017-03-01

    Re-Os isochron ages for black shales of the Hekkingen Formation in the Barents Sea constrain the onset (157.7 ± 1.3 Ma) and termination (138.8 ± 1.0 Ma), and thereby indicate a long duration (∼19 Myr) of widespread Jurassic-Cretaceous anoxia in the Arctic. Integration of these new Re-Os ages with published radiometric ages, ammonite biostratigraphy and geomagnetic polarity chrons shows shorter late Oxfordian-late Kimmeridgian and longer Berriasian stages relative to estimates in the 2012 and 2016 Geological Time Scales. Late Jurassic anoxia was likely the result of warming climate due to high atmospheric CO2 levels from increased oceanic crust production. Rising temperatures enhanced weathering and nutrient supply, increased productivity, and slowed ocean circulation before a sea-level rise brought anoxic waters onto continental shelves. Assessment of new and published Os- and Sr-isotopic data suggests that prolonged oceanic anoxia required a sustained CO2 source from fast spreading rates and/or longer subduction zones and spreading ridges to balance large burial of carbon in voluminous Upper Jurassic and Lower Cretaceous black shales.

  2. Bajocian-Bathonian (Middle Jurassic) sea-level changes in northeastern Egypt: Synthesis and further implications

    Science.gov (United States)

    Ruban, Dmitry A.; Sallam, Emad S.

    2016-08-01

    The global eustatic developments can benefit significantly from properly acquired regional information. Summarizing the available interpretations of the relative sea-level changes from two areas in northeastern Egypt, namely Gebel Maghara and Khashm El-Galala, allows better understanding of the Middle Jurassic sea-level changes. It is established that the Bajocian-Bathonian relative sea-level changes in these areas were coherent. The magnitude of changes was lower in the Bajocian than in the Bathonian. Significant sea-level rises occurred at the Bajocian-Bathonian and middle-late Bathonian transitions, and there was a clear tendency toward sea-level rise throughout the studied time interval. This evidence favors one of the two alternative global eustatic reconstructions that implies "stable" position of the shoreline in the Bajocian and general tendency to eustatic rise throughout the Jurassic. The tectonic regime of northeastern Egypt in the Middle Jurassic provided for strong eustatic control of the relative sea-level changes. The possible influence of hotspot activity is questionable. Filling the accommodation space with materials derived from the eroded continent may explain some sea-level falls that are regionally documented.

  3. Upper Jurassic basin axial turbidites within the Gertrud Graben, Danish Central Graben

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, E.S.; Jepsen, A.M.; Maver, K.G.

    1998-10-01

    Fore more than twenty years, the Jurassic succession in the Danish Central Graben has been subject to intense exploration for hydrocarbons. Approximately 43 wildcats have been drilled and most of these tested were structural traps located on footwall crests. The reservoirs encountered were Middle and Upper Jurassic sandstones deposited mainly in near shore depositional environments. Some of these wells penetrated thin turbidites of Late Jurassic to Early Cretaceous age. Within the Gertrud Graben distinct seismic anomalies indicate the presence of basin floor turbidites, which can be correlated to fan fringe turbites encountered in the Jeppe-1, Gwen-2 and Mona-1 wells. Within the Gertrud Graben, seismic anomalies characterized by high amplitude reflections with in an otherwise transparent reflection pattern have been recognized. The zone with high amplitude reflections correlates with thin turbidites with oil shows encountered in the Jeppe-1 well. The turbiditic sandstone succession has a gross thickness of 25 m and a net to gross of 75%, with porosity up to 10%. The presence of oil shows in the thin turbiditic sandstones in the Jeppe-1 well, drilled on a footwall crest, suggests the possibility of thicker sandstones in the basinal areas. The aim of this study is to map the distribution of the seismic anomalies by performing seismic inversion. Seismic inversion is used to derive acoustic impedance as a lithology indicator and to establish a geological model that is a likely prediction of the lithology and architecture of the depositional system. (EG) 2 fig., 17 refs.

  4. Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism

    Science.gov (United States)

    van de Schootbrugge, B.; Quan, T. M.; Lindström, S.; Püttmann, W.; Heunisch, C.; Pross, J.; Fiebig, J.; Petschick, R.; Röhling, H.-G.; Richoz, S.; Rosenthal, Y.; Falkowski, P. G.

    2009-08-01

    One of the five largest mass extinctions of the past 600million years occurred at the boundary of the Triassic and Jurassic periods, 201.6million years ago. The loss of marine biodiversity at the time has been linked to extreme greenhouse warming, triggered by the release of carbon dioxide from flood basalt volcanism in the central Atlantic Ocean. In contrast, the biotic turnover in terrestrial ecosystems is not well understood, and cannot be readily reconciled with the effects of massive volcanism. Here we present pollen, spore and geochemical analyses across the Triassic/Jurassic boundary from three drill cores from Germany and Sweden. We show that gymnosperm forests in northwest Europe were transiently replaced by fern and fern-associated vegetation, a pioneer assemblage commonly found in disturbed ecosystems. The Triassic/Jurassic boundary is also marked by an enrichment of polycyclic aromatic hydrocarbons, which, in the absence of charcoal peaks, we interpret as an indication of incomplete combustion of organic matter by ascending flood basalt lava. We conclude that the terrestrial vegetation shift is so severe and wide ranging that it is unlikely to have been triggered by greenhouse warming alone. Instead, we suggest that the release of pollutants such as sulphur dioxide and toxic compounds such as the polycyclic aromatic hydrocarbons may have contributed to the extinction.

  5. A Middle Jurassic heterodontosaurid dinosaur from Patagonia and the evolution of heterodontosaurids

    Science.gov (United States)

    Pol, Diego; Rauhut, Oliver W. M.; Becerra, Marcos

    2011-05-01

    Heterodontosauridae is a morphologically divergent group of dinosaurs that has recently been interpreted as one of the most basal clades of Ornithischia. Heterodontosaurid remains were previously known from the Early Jurassic of southern Africa, but recent discoveries and studies have significantly increased the geographical and temporal range for this clade. Here, we report a new ornithischian dinosaur from the Middle Jurassic Cañadón Asfalto Formation in central Patagonia, Argentina. This new taxon, Manidens condorensis gen. et sp. nov., includes well-preserved craniomandibular and postcranial remains and represents the only diagnostic ornithischian specimen yet discovered in the Jurassic of South America so far. Derived features of its anatomy indicate that Manidens belongs to Heterodontosauridae, as the sister taxon of Heterodontosaurus and other South African heterodontosaurids. The presence of posterior dentary teeth with high crowns but lacking extensive wear facets in Manidens suggests that this form represents an intermediate stage in the development of the remarkable adaptations to herbivory described for Heterodontosaurus. The dentition of Manidens condorensis also has autapomorphies, such as asymmetrically arranged denticles in posterior teeth and a mesially projected denticle in the posteriormost teeth. At an estimated total length of 60-75 cm, Manidens furthermore confirms the small size of basal heterodontosaurids.

  6. New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem.

    Science.gov (United States)

    Luo, Zhe-Xi; Meng, Qing-Jin; Grossnickle, David M; Liu, Di; Neander, April I; Zhang, Yu-Guang; Ji, Qiang

    2017-08-17

    Stem mammaliaforms are forerunners to modern mammals, and they achieved considerable ecomorphological diversity in their own right. Recent discoveries suggest that eleutherodontids, a subclade of Haramiyida, were more species-rich during the Jurassic period in Asia than previously recognized. Here we report a new Jurassic eleutherodontid mammaliaform with an unusual mosaic of highly specialized characteristics, and the results of phylogenetic analyses that support the hypothesis that haramiyidans are stem mammaliaforms. The new fossil shows fossilized skin membranes that are interpreted to be for gliding and a mandibular middle ear with a unique character combination previously unknown in mammaliaforms. Incisor replacement is prolonged until well after molars are fully erupted, a timing pattern unique to most other mammaliaforms. In situ molar occlusion and a functional analysis reveal a new mode of dental occlusion: dual mortar-pestle occlusion of opposing upper and lower molars, probably for dual crushing and grinding. This suggests that eleutherodontids are herbivorous, and probably specialized for granivory or feeding on soft plant tissues. The inferred dietary adaptation of eleutherodontid gliders represents a remarkable evolutionary convergence with herbivorous gliders in Theria. These Jurassic fossils represent volant, herbivorous stem mammaliaforms associated with pre-angiosperm plants that appear long before the later, iterative associations between angiosperm plants and volant herbivores in various therian clades.

  7. New Fossil Lepidoptera (Insecta: Amphiesmenoptera) from the Middle Jurassic Jiulongshan Formation of Northeastern China

    Science.gov (United States)

    Zhang, Weiting; Shih, Chungkun; Labandeira, Conrad C.; Sohn, Jae-Cheon; Davis, Donald R.; Santiago-Blay, Jorge A.; Flint, Oliver; Ren, Dong

    2013-01-01

    Background The early history of the Lepidoptera is poorly known, a feature attributable to an inadequate preservational potential and an exceptionally low occurrence of moth fossils in relevant mid-Mesozoic deposits. In this study, we examine a particularly rich assemblage of morphologically basal moths that contribute significantly toward the understanding of early lepidopteran biodiversity. Methodology/Principal Findings Our documentation of early fossil moths involved light- and scanning electron microscopic examination of specimens, supported by various illumination and specimen contrast techniques. A total of 20 moths were collected from the late Middle Jurassic Jiulongshan Formation in Northeastern China. Our principal results were the recognition and description of seven new genera and seven new species assigned to the Eolepidopterigidae; one new genus with four new species assigned to the Mesokristenseniidae; three new genera with three new species assigned to the Ascololepidopterigidae fam. nov.; and one specimen unassigned to family. Lepidopteran assignment of these taxa is supported by apomorphies of extant lineages, including the M1 vein, after separation from the M2 vein, subtending an angle greater than 60 degrees that is sharply angulate at the junction with the r–m crossvein (variable in Trichoptera); presence of a foretibial epiphysis; the forewing M vein often bearing three branches; and the presence of piliform scales along wing veins. Conclusions/Significance The diversity of these late Middle Jurassic lepidopterans supports a conclusion that the Lepidoptera–Trichoptera divergence occurred by the Early Jurassic. PMID:24278142

  8. New robertinid foraminifers from the Early Jurassic of Adnet, Austria and their evolutionary importance

    Directory of Open Access Journals (Sweden)

    Sylvain Rigaud

    2016-12-01

    Full Text Available New benthic multichambered foraminifers have been discovered in the Hettangian–Sinemurian of the Northern Calcareous Alps (Adnet, Salzburg, Austria. Originally aragonitic, these forms are completely recrystallized but the early impregnation of their tests by Fe-Mn solutions has, to some extent, allowed an indirect preservation of their primary structure. The most remarkably preserved specimens are found in close vicinity to the marmorea crust, a heavily mineralized multiphased hardground. We describe two new genera, Velleditsiella gen. nov., a microgastropod look-alike foraminifer, which includes the species V. felicitaszae gen. et sp. nov. and V. spinaferra gen. et sp. nov., and Rossanella gen. nov., the first known representative of the superfamily Conorboidoidea, which includes the species R. martinii gen. et sp. nov. Considering their structural and morphological characteristics, Velleditsiella and Rossanella phylogenetically derive from two distinct Triassic lineages, respectively the families Trochosiphoniidae and Variostomatidae. The discovery of diverse aragonitic assemblages in earliest Jurassic strata dismisses the long believed hypothesis that all Jurassic aragonitic multichambered foraminifers originated from a single Oberhauserellidae ancestor. It also supports a lower impact of the Triassic/Jurassic biotic crisis on the evolution of aragonitic foraminifers. Hypotheses for the short term and long term evolution of aragonitic multichambered foraminifers are discussed and new phyletic trees are proposed.

  9. New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem

    Science.gov (United States)

    Luo, Zhe-Xi; Meng, Qing-Jin; Grossnickle, David M.; Liu, Di; Neander, April I.; Zhang, Yu-Guang; Ji, Qiang

    2017-08-01

    Stem mammaliaforms are forerunners to modern mammals, and they achieved considerable ecomorphological diversity in their own right. Recent discoveries suggest that eleutherodontids, a subclade of Haramiyida, were more species-rich during the Jurassic period in Asia than previously recognized. Here we report a new Jurassic eleutherodontid mammaliaform with an unusual mosaic of highly specialized characteristics, and the results of phylogenetic analyses that support the hypothesis that haramiyidans are stem mammaliaforms. The new fossil shows fossilized skin membranes that are interpreted to be for gliding and a mandibular middle ear with a unique character combination previously unknown in mammaliaforms. Incisor replacement is prolonged until well after molars are fully erupted, a timing pattern unique to most other mammaliaforms. In situ molar occlusion and a functional analysis reveal a new mode of dental occlusion: dual mortar-pestle occlusion of opposing upper and lower molars, probably for dual crushing and grinding. This suggests that eleutherodontids are herbivorous, and probably specialized for granivory or feeding on soft plant tissues. The inferred dietary adaptation of eleutherodontid gliders represents a remarkable evolutionary convergence with herbivorous gliders in Theria. These Jurassic fossils represent volant, herbivorous stem mammaliaforms associated with pre-angiosperm plants that appear long before the later, iterative associations between angiosperm plants and volant herbivores in various therian clades.

  10. Geochronology and petrogenesis of Middle Permian S-type granitoid in southeastern Guangxi Province, South China: Implications for closure of the eastern Paleo-Tethys

    Science.gov (United States)

    Li, Yan-Jun; Wei, Jun-Hao; Santosh, M.; Tan, Jun; Fu, Le-Bing; Zhao, Shao-Qing

    2016-07-01

    The Bangxi-Chenxing suture zone is an important region to address the history of closure of the eastern Paleo-Tethys ocean. Among the widespread S-type granite batholiths in the SE Guangxi Province adjacent to this suture is the Nali granodiorite. Here we report zircon U-Pb ages, major and trace element geochemistry, and Sr-Nd-Hf isotope geochemistry of a newly found Middle Permian S-type granite in this region. LA-ICP-MS zircon U-Pb geochronology yields emplacement ages of 265 ± 2 to 262 ± 2 Ma for the Nali granodiorite. Both the inner and outer phases are characterized by variable SiO2 (66.91-71.39 wt.%), high Al2O3 (12.99-14.04 wt.%), K2O + Na2O (4.78-5.98 wt.%), and A/CNK values (1.11-1.50), resembling those of typical S-type granites. The rocks are enriched in Rb, Th, U and light rare earth elements with weak negative Eu anomalies, and show depletion in Nb, Ta, Ti, with typical arc-like affinity. They have relatively high (87Sr/86Sr)i ratios of 0.7228 to 0.7331, low εNd(t) values of - 13.6 to - 11.9, and low zircon εHf(t) values (- 21.9 to - 8.8). High whole-rock Nd isotopic model ages (2.00-2.02 Ga) and zircon Hf isotopic model ages (1.59-2.20 Ga), indicate that they might have been generated by partial melting of ancient lower crust with minor contribution from mantle sources. The granodiorite shows continental arc affinity and likely formed within a subduction setting. By combining previously extant data for Permo-Triassic arc-/collision-related magmatism in the Jinshajiang-Ailaoshan-Song Ma and Bangxi-Chenxing suture zones, we propose that the subduction of the eastern Paleo-Tethys might have started during Middle Permian triggered by the northward subduction of the Indochina Block (ICB) beneath the South China Block (SCB) and closure during Middle Triassic.

  11. Bridging the Faraoni and Selli oceanic anoxic events: short and repetitive dys- and anaerobic episodes during the late Hauterivian to early Aptian in the central Tethys

    Science.gov (United States)

    Föllmi, K. B.; Bôle, M.; Jammet, N.; Froidevaux, P.; Godet, A.; Bodin, S.; Adatte, T.; Matera, V.; Fleitmann, D.; Spangenberg, J. E.

    2011-06-01

    A detailed stratigraphical and geochemical analysis was performed on the upper part of the Maiolica Formation outcropping in the Breggia (southern Switzerland) and Capriolo sections (northern Italy). In these localities, the Maiolica Formation consists of well-bedded, partly siliceous, pelagic, micritic carbonate, which lodges numerous thin, dark and organic-rich layers. Stable-isotope, phosphorus, organic-carbon and a suite of redox-sensitive trace-metal contents (RSTE: Mo, U, Co, V and As) were measured. Higher densities of organic-rich layers were identified in the uppermost Hauterivian, lower Barremian and the Barremian-Aptian boundary intervals, whereas the upper Barremian interval and the interval immediately following the Barremian-Aptian boundary interval are characterized by lower densities of organic-rich layers. TOC contents, RSTE pattern and Corg:Ptot ratios indicate that most layers were deposited under dysaerobic rather than anaerobic conditions and that latter conditions were likely restricted to short intervals in the latest Hauterivian, the early Barremian and the pre-Selli early Aptian. Correlations are possible with organic-rich intervals in central Italy (the Gorgo a Cerbara section) and the Boreal northwest German Basin, and with the facies and drowning pattern in the evolution of the Helvetic segment of the northern Tethyan carbonate platform. Our data and correlations suggest that the latest Hauterivian witnessed the progressive installation of dysaerobic conditions in the Tethys, which went along with the onset in sediment condensation, phosphogenesis and platform drowning on the northern Tethyan margin, and which culminated in the Faraoni anoxic episode. This brief episode is followed by further episodes of dysaerobic conditions in the Tethys and the northwest German Basin, which became more frequent and progressively stronger in the late early Barremian. Platform drowning persisted and did not halt before the latest early Barremian. The

  12. Investigation of a hydrological system related to the stability of slope sediments off the Nice Aiport, Ligurian Sea - preliminary data and a sketch for a MSP drilling proposal

    Science.gov (United States)

    Henry, P.; Stegmann, S.; Sultan, N.; Sage, F.; Migeon, S.; Kopf, A.

    2009-04-01

    The sedimentary instability of submarine slopes poses a major geohazard and threatens coastal infrastructure both on- and offshore. The Ligurian Margin, Southern France, represents such a potentially unstable slope where factors favouring instability include seismicity, groundwater charging, presence of weak minerals, high sediment accumulation rates, anthropogenic impact by construction, and slope oversteepening. On the 16th of October 1979 a major submarine landslide (~8.7 km2) affected the coastal system offshore Nice and resulted in destruction of an embankment at the Nice airport, a debris flow cutting two submarine cables tens of kilometres away from the sliding area, and a tsunami wave of 2-3 m at the nearby coast. It was proposed several years ago that overpressuring linked to the hydrogeological condition could have been the trigger mechanism of the Nice Airport failure, and seawater composition in this area further suggested that fresh ground water is released offshore by coastal aquifers. The hydrogeological triggering model is also supported by sedimentary and seismic data indicating that gently seaward-dipping permeable layers of sediment may provide aquifer pathways down to a maximum depth of 150 m. An investigation of the superficial sediments (max. 30 mbsf) was recently performed in close collaboration between France (e.g. PRISME cruise with RV L'Atalante, 2007) and Germany (e.g. M73 cruise with RV Meteor, 2007). The study included geophysical acquisition, in situ pore pressure and shear strength measurements (CPTU devices, Penfeld penetrometer) as well as gravity coring. For long- and mid-term measurements, piezometers, which acquire the pore pressure at five different depth levels within the sediment, were installed by IFREMER Brest, France. Short-term measurements were carried out with the marine shallow-water FF-CPTU probe by the MARUM Bremen, Germany, while geochemical analysis was performed on pore water extracted from the cores. The main

  13. Project Seacleaner: from cooperation among ISMAR-CNR researchers, high school students and the Ligurian Cluster for Marine Technologies to an application for environmental monitoring and scientific research.

    Science.gov (United States)

    Merlino, Silvia; Marini, Claudio; Tosi, Daniela; Caselli, Lorena; Marini, Davide; Lucchinelli, Paolo; Vatteroni, Davide; Lunardelli, Francesco; Agrusa, Astrid; Lombardi, Davide; Stroobant, Mascha

    2014-05-01

    Recently, the Institute for Marine Science of the Italian Research Council ISMAR-CNR has undertaken a series of actions to incorporate oceanography in education: among these, the project "SeaCleaner" that has been developed together with a local Secondary School (Istituto di Istruzione Superiore Capellini-Sauro) and the Ligurian Cluster for Marine Technologies (DLTM) [1]. Seven students, engaged within the national Programme "work-related learning"[2], have worked side-by-side with ISMAR-CNR researchers, investigating on the problem of debris accumulation on beaches, and understanding the damage that this issue causes to marine environments and ecosystems. This problem has recently become a challenging research subject for an increasing number of oceanographers and, in general, for environmental researchers coming from the Mediterranean areas [3, 4, 5], other European Seas [6] and Oceans [7, 8]. Data collected during repeated surveys (seasonally) in the same beach stretch, over several years, allow calculating debris accumulation rates and flow intensities. Application of current models gives additional information on debris dispersal and origin, but we shouldn't forget that, generally, relevance of acquired data is determined by the accuracy and standardization of the procedure. In this context, students have previously searched for literature sources and summarized the most important issues, among these: few data that are often collected during small ranges of time and usually a low number of available researchers for carrying out such a time-consuming survey in the field. In a initial part of the project, several trial surveys have been performed on different beaches in La Spezia province, in order to understand how to elaborate possible strategies to speed up and standardize the procedure. Developing an application for Android system (downloadable on any compatible mobile device such as smartphones, tablets, etc.) has been considered as a good solution since it

  14. Reply to comment by W. Liu and B. Xia on "Age and geochemistry of western Hoh-Xil-Songpan-Ganzi granitoids, northern Tibet: Implications for the Mesozoic closure of the Paleo-Tethys ocean"

    Science.gov (United States)

    Zhang, Li-Yun; Ding, Lin; Pullen, Alex; Kapp, Paul

    2015-01-01

    The process of rapid extensional back-arc basin development, sediment infilling, and oceanic trench migration during collisional orogenesis-commonly referred to as slab rollback or Mediterranean-style tectonics-has been widely documented in modern global tectonics (e.g., Le Pichon and Angelier, 1981; Malinverno and Ryan, 1986; Spakman and Hall, 2010). This process, however, may be underappreciated in the development of ancient orogenic systems where the rates of oceanic subduction relative to plate convergence are poorly constrained or unknown. Some notable exception include the Lachlan orogen (e.g., Collins, 2002; Kemp et al., 2009), the closure of the Rheic Ocean (Martínez Catalán et al., 2009; Stampfli and Borel, 2002), and the eastern Paleo-Tethys Ocean discussed here (Ding et al., 2013; Pullen et al., 2008). We maintain that the valid geological observations made by Liu and Xia (2014) do not invalidate nor necessitate modification to the Mesozoic Paleo-Tethys rollback model presented by Zhang et al. (2014). We begin by summarizing the Mediterranean-style tectonic model applied to the evolution of the Paleo-Tethys Ocean and then discuss how the observations and points made by Liu and Xia (2014) may be addressed within the context of it.

  15. The Jurassic petroleum system north and west of Britain: a geochemical oil-source correlation study

    Energy Technology Data Exchange (ETDEWEB)

    Scotchman, I.C. [Statoil Ltd., London (United Kingdom); Griffith, C.E.; Holmes, A.J. [Mobil North Sea Ltd., London (United Kingdom); Jones, D.M. [University of Newcastle (United Kingdom). Newcastle Research Group in Fossil Fuels and Environmental Geochemistry

    1998-12-31

    Recent significant oil discoveries have focused exploration attention on the Atlantic Margin areas north and west of Britain, in particular the West of Shetlands area. These discoveries, the Foinaven and Schiehallion fields, each have reserves of 250 to 500 million barrels (39.8 to 79.5 x 10{sup 6} m{sup 3}) of 24-27 {sup o} API oil while an earlier heavy oil discovery, the Clair Field, is the largest undeveloped oil discovery on the U.K. Continental Shelf with resources estimated in the range 3-5 billion barrels (477 to 795 x 10{sup 6} m{sup 3}). Other discoveries include Suilven, the very heavy oil in well 204/28-1 and the Quadrant 205 Strathmore and Solan fields. Potential source rocks in areas adjacent to the West of Shetlands include the Upper Jurassic Kimmeridge CLay Formation equivalent, the Middle and Lower Jurassic and the Middle Devonian. The results of geochemical studies of the oils, reservoir core extracts and source rocks from released wells from these West of Shetlands discoveries show them to be genetically related to North Sea oils sourced from the Kimmeridge Clay Formation equivalent. Detailed geochemical analysis (biomarkers, source rock reaction kinetics, compound specific isotope analysis and fluid inclusion ``crush-leach`` analysis) of the Clair Field and ``Foinaven Complex`` oils showed that at least two episodes of charging from different source facies within the Kimmeridge Clay Formation took place, with an intervening biodegradation event. Oil charging from Middle Jurassic lacustrine source rocks is also indicated in the ``Foinaven Complex`` oils. The source rocks are shown to exhibit variations in organic facies, from very oil-prone to mixed oil and gas, with a corresponding range of kinetic parameters. This complex generation, migration and trapping scenario is directly linked with the tectonic evolution of the West of Shetlands with major oil generation from very oil-prone Kimmeridge Clay and Middle Jurassic lacustrine facies into

  16. New model for Jurassic microcontinent movement and Gondwana breakup in the Weddell Sea region

    Science.gov (United States)

    Jordan, Tom; Ferraccioli, Fausto; Leat, Philip

    2017-04-01

    The breakup of the Gondwana supercontinent changed the face of our planet. Precursors of supercontinental breakup are widely recognised in the Weddell Sea region in the Jurassic. These include the Karoo/Ferrar Large Igneous Province that extends from South Africa to East Antarctica and significant continental rifting and associated translation of microcontinental blocks in the Weddell Sea Embayment region. However, significant controversy surrounds the pre-breakup position, extent, timing and driving mechanism of inferred microcontinental movement. In particular geological and paleomagnetic data suggest >1000 km of translation and 90 degree rotation of the Haag-Ellsworth Whitmore block (HEW) away from East Antarctica. In contrast, some geophysical interpretations suggest little or no Jurassic or subsequent HEW block movement. Here we present a simpler tectonic model for the Weddell Sea Rift System and HEW movement, derived from our new compilation of airborne geophysical data, satellite magnetic data and potential field modelling (Jordan et al., 2016- Gondwana Res.). Based on the amount of inferred Jurassic crustal extension and pattern of magnetic anomalies we propose that the HEW was translated 500 km towards the Paleo-Pacific margin of Gondwana, possibly in response to a process of slab roll-back that led to distributed back-arc extension in the Weddell Sea Rift System. Widespread magmatism in the region was likely influenced by the presence of one or more mantle plumes impinging beneath the stretching lithosphere. A second phase of continental extension is inferred to have occurred between 180 and 165 Ma (prior to seafloor spreading) and is more closely associated with Gondwana breakup. This second phase over-printed the northern part of the older back arc system. We find no geophysical evidence indicating more than 30 degrees of syn-extensional HEW rotation during Jurassic rifting in the southern Weddell Sea Rift System. Instead, we propose the majority ( 60

  17. The Tunisian Jurassic aquifer in the North African Sahara aquifer system: information derived from two-dimensional seismic reflection and well logs

    Science.gov (United States)

    Ben Lasmar, Rafika; Guellala, Rihab; Garrach, Mohamed; Mahroug, Ali; Sarsar Naouali, Benen; Inoubli, Mohamed Hédi

    2017-07-01

    Southern Tunisia is an arid area where socio-economic activities are dependent on groundwater resources. The presented study aims to better characterize the Jurassic aquifer based on geological and geophysical data, with a view to develop a rational exploitation program. Well logs are used to precisely determine the position and composition of the known Jurassic aquifer layers and to identify others able to produce good quality water. The logs show that limestones, sandstones and dolomites of the Krachoua, Techout and Foum Tataouine formations are the main Jurassic aquifers. Sixty-eight seismic-reflection sections are integrated within this study. The interpolation between the interpreted sections leads to the construction of isochronous isopach maps and geoseismic sections, and their analysis finds that compressive and extensive tectonic deformations have influenced the Jurassic aquifer geometry. The Hercynian orogeny phase manifestation is remarkable in that there are several stratigraphic gaps in the Jurassic sequence. The E-W, NW-SE, and NNW-SSE accidents, reactivated in normal faults since the Permian to Lower Cretaceous epochs, have generated the structures found in the Jurassic series, such as subsided and raised blocks. Their syn-sedimentary activity has controlled the thickness and facies of these series. The Cretaceous, Tortonian and Post-Villafranchian compressions are responsible for the Jurassic-deposits folding in some localities. The highlighted tectonic and sedimentary events have an important impact on the Jurassic aquifer function by favoring the Jurassic aquifer interconnections and their connections with the Triassic and Cretaceous permeable series.

  18. Jurassic fishes of Gondwana Peces jurásicos de Gondwana

    Directory of Open Access Journals (Sweden)

    Adriana López-Arbarello

    2008-12-01

    Full Text Available The Jurassic is an important period for understanding the origin of modern fish faunas, since it saw the first radiation - and in some cases the origin - of most modern groups. In chondrichthyans, neoselachian sharks and rays diversified during this time. In actinopterygians, the neopterygians, and among them the teleosts, experienced an important radiation, which led to the appearance of several of the modern teleosts groups. In the sarcopterygians, dipnoans and actinistians approached their current forms. However, the Jurassic fossil record of fishes is strongly biased towards the Northern Hemisphere. The only notable Early Jurassic fish fauna from Gondwana is that of the Kota Formation of India. For the Middle Jurassic, the most important Gondwanan fish faunas are those of the Aalenian-Bathonian Stanleyville Beds of the Democratic Republic of Congo, in which a distinct freshwater and a marine fauna are found. In the Late Jurassic, the Gondwanan record is slightly better, with important marine faunas being known from the Oxfordian Quebrada del Profeta in Chile and the Tithonian Vaca Muerta Formation of Argentina. Freshwater faunas have been described from the Tithonian Talbragar Beds of eastern Australia and the Tithonian Cañadón Calcáreo Formation of Argentina. The taxonomic composition of the known marine actinopterygian faunas of Gondwana is in general agreement with faunas of the Northern Hemisphere. However, the Jurassic fish record from Gondwana is highly incomplete both stratigraphically and geographically, and most faunas are in need of revision, further hampering an interpretation of Jurassic fish evolution in the Southern Hemisphere.El Período Jurásico es muy importante para entender el origen de las ictiofaunas modernas, dado que evidenció la primera radiación - y en algunos casos el origen - de la mayoría de los grupos modernos. Así, los condrictios neoselacios se diversificaron durante este periodo. Los actinopterigios

  19. A one-month study of the zooplankton community at a fixed station in the Ligurian Sea: the potential impact of the species composition on the mineralization of organic matter

    Directory of Open Access Journals (Sweden)

    L. Mousseau

    2009-01-01

    Full Text Available The cruise project was designed to study temporal variations of the ecosystem during the summer-autumn transition and focused on the part played by zooplankton as top-down controllers, and the relative importance of top-down versus bottom-up controls. Zooplankton should play a key role both in the vertical transfer of particulate organic matter and in the mineralisation of organic matter. Although the importance of species diversity is well recognized, the impact of diversity on carbon fluxes is rarely considered. Trophic roles of zooplankton range from strict herbivory to strict carnivory, with all possible combinations (i.e. omnivory between these two extremes. Feeding strategies are also very diverse, for example, active predators, passive filter feeders or suspension feeders co-exist (Bamstedt at al., 2000. As the metabolic cost of these different trophic roles and ways of feeding should be different, a physiological diversity must be considered in any assessment of the role of zooplankton in the flux of organic matter (e.g. Longhurts and Harrison, 1989. At a minimum,, species and functional diversities contribute to the diversity of exported organic matter (Steinberg et al., 2000; Madin et al., 2001. Fecal pellets, the organic matter egested by zooplankton, differ in form, size and weight, and hence in their sedimentation and degradation rates (Turner, 2002. The downward flux of organic matter thus depends on not only on physical and chemical processes but also on biological variables.

    The area sampled, located in the central part of the Ligurian Sea is next to the DYFAMED site, a time-series station monthly monitored for several years now. The zone is considered to be oligotrophic and protected from strong advective processes (Andersen and Prieur, 2000. The two cruises DYNAmic of the rapid PROCess (DYNAPROC 1 in May 1995 and DYNAPROC 2, the present study were devoted to factors controlling the vertical flux of matter on short time

  20. The Jurassic of Denmark and Greenland: The Jurassic of East Greenland: a sedimentary record of thermal subsidence, onset and culmination of rifting

    Directory of Open Access Journals (Sweden)

    Surlyk, Finn

    2003-10-01

    Full Text Available The Late Palaeozoic – Mesozoic extensional basin complex of East Greenland contains a record of deposition during a period of Rhaetian – Early Bajocian thermal subsidence, the onset of riftingin the Late Bajocian, its growth during the Bathonian–Kimmeridgian, culmination of rifting in the Volgian – Early Ryazanian, and waning in the Late Ryazanian – Hauterivian. The area was centred over a palaeolatitude of about 45°N in the Rhaetian and drifted northwards to about 50°N in the Hauterivian. A major climate change from arid to humid subtropical conditions took place at the Norian–Rhaetian transition. Deposition was in addition governed by a long-term sea-level rise with highstands in the Toarcian–Aalenian, latest Callovian and Kimmeridgian, and lowstands in the latest Bajocian – earliest Bathonian, Middle Oxfordian and Volgian.The Rhaetian – Lower Bajocian succession is considered the upper part of a megasequence, termed J1, with its base in the upper Lower Triassic, whereas the Upper Bajocian – Hauterivian succession forms a complete, syn-rift megasequence, termed J2. The southern part of the basin complex in Jameson Land contains a relatively complete Rhaetian–Ryazanian succession and underwent only minor tilting during Middle Jurassic – earliest Cretaceous rifting. Rhaetian – Lower Jurassic deposits are absent north of Jameson Land and this region was fragmented into strongly tilted fault blocks during the protracted rift event. The syn-rift successions of the two areas accordingly show different long-term trends in sedimentary facies. In the southern area, the J2 syn-rift megasequence forms a symmetrical regressive–transgressive–regressive cycle, whereas the J2 megasequence in the northern area shows an asymmetrical, stepwise deepening trend.A total of eight tectonostratigraphic sequences are recognised in the Rhaetian–Hauterivian interval. They reflect major changes in basin configuration, drainage systems

  1. Palaeoclimatic conditions in the Late Triassic-Early Jurassic of southern Africa: A geochemical assessment of the Elliot Formation

    Science.gov (United States)

    Sciscio, Lara; Bordy, Emese M.

    2016-07-01

    The Triassic-Jurassic boundary marks a global faunal turnover event that is generally considered as the third largest of five major biological crises in the Phanerozoic geological record of Earth. Determining the controlling factors of this event and their relative contributions to the biotic turnover associated with it is on-going globally. The Upper Triassic and Lower Jurassic rock record of southern Africa presents a unique opportunity for better constraining how and why the biosphere was affected at this time not only because the succession is richly fossiliferous, but also because it contains important palaeoenvironmental clues. Using mainly sedimentary geochemical proxies (i.e., major, trace and rare earth elements), our study is the first quantitative assessment of the palaeoclimatic conditions during the deposition of the Elliot Formation, a continental red bed succession that straddles the Triassic-Jurassic boundary in southern Africa. Employing clay mineralogy as well as the indices of chemical alteration and compositional variability, our results confirm earlier qualitative sedimentological studies and indicate that the deposition of the Upper Triassic and Lower Jurassic Elliot Formation occurred under increasingly dry environmental conditions that inhibited chemical weathering in this southern part of Pangea. Moreover, the study questions the universal validity of those studies that suggest a sudden increase in humidity for the Lower Jurassic record and supports predictions of long-term global warming after continental flood basalt emplacement.

  2. Hadley circulation and precipitation changes controling black shale deposition in the Late Jurassic Boreal Seaway

    Science.gov (United States)

    Armstrong, Howard A.; Wagner, Thomas; Herringshaw, Liam G.; Farnsworth, Alexander J.; Lunt, Daniel J.; Harland, Melise; Imber, Jonathan; Loptson, Claire; Atar, Elizabeth F. L.

    2016-08-01

    New climate simulations using the HadCM3L model with a paleogeography of the Late Jurassic (155.5 Ma) and proxy-data corroborate that warm and wet tropical-like conditions reached as far north as the UK sector of the Jurassic Boreal Seaway (~35°N). This is associated with a northern hemisphere Jurassic Hadley cell and an intensified subtropical jet which both extend significantly poleward than in the modern (July-September). Deposition of the Kimmeridge Clay Formation (KCF) occurred in the shallow, storm-dominated, epeiric Boreal Seaway. High-resolution paleo-environmental proxy data from the Kimmeridge Clay Formation (KCF; ~155-150 Ma), UK, are used to test for the role of tropical atmospheric circulation on meter-scale heterogeneities in black shale deposition. Proxy and model data show that the most organic-rich section (eudoxus to mid-hudlestoni zones) is characterized by a positive δ13Corg excursion and up to 37 wt % total organic carbon (%TOC). Orbital modulation of organic carbon burial primarily in the long eccentricity power band combined with a clear positive correlation between %TOC carbonate-free and the kaolinite/illite ratio supports peak organic carbon burial under the influence of very humid climate conditions, similar to the modern tropics. This reinterpretation of large-scale climate relationships, supported by independent modeling and geological data, has profound implications for atmospheric circulation patterns and processes affecting marine productivity and organic carbon burial further north along the Boreal Seaway, including the Arctic.

  3. Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains.

    Science.gov (United States)

    Reisz, Robert R; Huang, Timothy D; Roberts, Eric M; Peng, ShinRung; Sullivan, Corwin; Stein, Koen; LeBlanc, Aaron R H; Shieh, DarBin; Chang, RongSeng; Chiang, ChengCheng; Yang, Chuanwei; Zhong, Shiming

    2013-04-11

    Fossil dinosaur embryos are surprisingly rare, being almost entirely restricted to Upper Cretaceous strata that record the late stages of non-avian dinosaur evolution. Notable exceptions are the oldest known embryos from the Early Jurassic South African sauropodomorph Massospondylus and Late Jurassic embryos of a theropod from Portugal. The fact that dinosaur embryos are rare and typically enclosed in eggshells limits their availability for tissue and cellular level investigations of development. Consequently, little is known about growth patterns in dinosaur embryos, even though post-hatching ontogeny has been studied in several taxa. Here we report the discovery of an embryonic dinosaur bone bed from the Lower Jurassic of China, the oldest such occurrence in the fossil record. The embryos are similar in geological age to those of Massospondylus and are also assignable to a sauropodomorph dinosaur, probably Lufengosaurus. The preservation of numerous disarticulated skeletal elements and eggshells in this monotaxic bone bed, representing different stages of incubation and therefore derived from different nests, provides opportunities for new investigations of dinosaur embryology in a clade noted for gigantism. For example, comparisons among embryonic femora of different sizes and developmental stages reveal a consistently rapid rate of growth throughout development, possibly indicating that short incubation times were characteristic of sauropodomorphs. In addition, asymmetric radial growth of the femoral shaft and rapid expansion of the fourth trochanter suggest that embryonic muscle activation played an important role in the pre-hatching ontogeny of these dinosaurs. This discovery also provides the oldest evidence of in situ preservation of complex organic remains in a terrestrial vertebrate.

  4. TRIASSIC AND JURASSIC CALCAREOUS NANNOFOSSILS OF THE PIZZO MONDELLO SECTION: A SEM STUDY

    Directory of Open Access Journals (Sweden)

    NEREO PRETO

    2012-03-01

    Full Text Available Pizzo Mondello is a ca. 500 m thick pelagic-hemipelagic succession cropping out in Sicily consisting of a nodular cherty limestone facies association of late Carnian to late Norian age. The uppermost portion was attributed to the Rhaetian and is represented by the plane-bedded Portella Gebbia Limestone. The section has been proposed as the stratotype for the base of the Norian stage. The calcareous nannofossil content of limestones was studied with Scanning Electron Microscope (SEM in two portions of the Pizzo Mondello section, one within 'La Cava' that encompasses all the proposed horizons for the base of the Norian, and one within the Portella Gebbia Limestone in the uppermost part of the section.Calcareous nannofossil assemblages of the first portion display low diversity, being constituted exclusively by calcispheres, that may constitute up to 40% of the sediment volume. Species richness increases in the upper portion. Initially, samples are dominated by Prinsiosphaera triassica, a nannolith of unknown taxonomic affinity. Rare calcareous dinocysts (Thoracosphaera cf. geometrica and coccoliths are present in few samples. Uppermost samples are still dominated by "calcispheres" comparable to Thoracosphaera, but also yield a variety of coccoliths and nannoliths.Calcareous nannofossil distribution was calibrated with conodont and radiolarian biostratigraphy. On the basis of this integrated work, specimens attributed to cf. Thoracosphaera, observed in the lower portion of the section, are late Carnian to early Norian, while samples dominated by Prinsiosphaera, with rare Thoracosphaera and coccoliths are Rhaetian. The calcareous nannofossil assemblage of the uppermost samples, along with radiolarians and the absence of conodonts, point to a Jurassic age (Pliensbachian for the uppermost Portella Gebbia Limestone at Pizzo Mondello. In conclusion, the age of the uppermost part of the Pizzo Mondello section is Jurassic, i.e., younger than previously

  5. On a pterosaur jaw from the Upper Jurassic of Tendaguru (Tanzania

    Directory of Open Access Journals (Sweden)

    D. M. Unwin

    1999-01-01

    Full Text Available A short section of a mandibular symphysis is the first cranial fossil of a pterosaur to be reported from the Upper Jurassic of Tendaguru, Tanzania. It is made the holotype of a new dsungaripteroid pterosaur, Tendaguripterus recki n. gen. n. sp. All previously named pterosaur taxa from Tendaguru are shown to be nomina dubia. The pterosaur assemblage from Tendaguru contains a "rhamphorhynchoid", as well as the dsungaripteroid, and is similar in its systematic composition to other Late Jurassic pterosaur assemblages from Laurasia. The diversity and broad distribution of dsungaripteroids in the Late Jurassic suggests that the group was already well established by this time. Der erste Schädelrest eines Flugsauriers aus dem Oberjura von Tendaguru in Tansania wird beschrieben. Bei dem Fundstück handelt es sich um ein bezahntes Unterkieferbruchstück aus der Symphysenregion. Der Fund gehört zu einem neuen Taxon, das als Tendaguripterus recki n. gen. n. sp. bezeichnet und zur Überfamilie Dsungaripteroidea gestellt wird. Alle zuvor aus den Tendaguru-Schichten beschriebenen Taxa werden als nomina dubia angesehen. In Tendaguru sind Verteter der „Rhamphorhynchoidea“ und Dsungaripteroidea nachgewiesen. Diese systematische Zusammensetzung ist derjenigen anderer Flugsaurier-Vergesellschaftungen der späten Jura-Zeit ähnlich. Die Vielfalt und die weite Verbreitung der Dsungaripteroidea in Laurasia läßt darauf schließen, daß sich diese Flugsauriergruppe bereits in der späten Jura-Zeit erfolgreich durchgesetzt hatte. doi:10.1002/mmng.1999.4860020109

  6. Mesozoic (Upper Jurassic-Lower Cretaceous) deep gas reservoir play, central and eastern Gulf coastal plain

    Science.gov (United States)

    Mancini, E.A.; Li, P.; Goddard, D.A.; Ramirez, V.O.; Talukdar, S.C.

    2008-01-01

    The Mesozoic (Upper Jurassic-Lower Cretaceous) deeply buried gas reservoir play in the central and eastern Gulf coastal plain of the United States has high potential for significant gas resources. Sequence-stratigraphic study, petroleum system analysis, and resource assessment were used to characterize this developing play and to identify areas in the North Louisiana and Mississippi Interior salt basins with potential for deeply buried gas reservoirs. These reservoir facies accumulated in Upper Jurassic to Lower Cretaceous Norphlet, Haynesville, Cotton Valley, and Hosston continental, coastal, and marine siliciclastic environments and Smackover and Sligo nearshore marine shelf, ramp, and reef carbonate environments. These Mesozoic strata are associated with transgressive and regressive systems tracts. In the North Louisiana salt basin, the estimate of secondary, nonassociated thermogenic gas generated from thermal cracking of oil to gas in the Upper Jurassic Smackover source rocks from depths below 3658 m (12,000 ft) is 4800 tcf of gas as determined using software applications. Assuming a gas expulsion, migration, and trapping efficiency of 2-3%, 96-144 tcf of gas is potentially available in this basin. With some 29 tcf of gas being produced from the North Louisiana salt basin, 67-115 tcf of in-place gas remains. Assuming a gas recovery factor of 65%, 44-75 tcf of gas is potentially recoverable. The expelled thermogenic gas migrated laterally and vertically from the southern part of this basin to the updip northern part into shallower reservoirs to depths of up to 610 m (2000 ft). Copyright ?? 2008. The American Association of Petroleum Geologists. All rights reserved.

  7. Embryos of an early Jurassic prosauropod dinosaur and their evolutionary significance.

    Science.gov (United States)

    Reisz, Robert R; Scott, Diane; Sues, Hans-Dieter; Evans, David C; Raath, Michael A

    2005-07-29

    Articulated embryos from the Lower Jurassic Elliot Formation of South Africa are referable to the prosauropod Massospondylus carinatus and, together with other material, provide substantial insights into the ontogenetic development in this early dinosaur. The large forelimbs and head and the horizontally held neck indicate that the hatchlings were obligate quadrupeds. In contrast, adult Massospondylus were at least facultatively bipedal. This suggests that the quadrupedal gait of giant sauropods may have evolved by retardation of postnatal negative allometry of the forelimbs. Embryonic body proportions and an absence of well-developed teeth suggest that hatchlings of this dinosaur may have required parental care.

  8. New Fossils of Eoptychopteridae (Diptera)from the Middle Jurassic of Northeastern China

    Institute of Scientific and Technical Information of China (English)

    HAO Jianying; REN Dong; SHIH Chungkun

    2009-01-01

    Three new species of the extinct genus of Eoptychopterina from the Eoptychopteridae family, Eoptychopterina antica sp. nov., Eoptychopterina adnexa sp. nov., and Eoptychopterina mediata sp. nov., are described and illustrated. These three new species are established based on fossil specimens with bodies and complete wings. All were collected from the Middle Jurassic Jiulongshan Formation of Daohugou in eastern Inner Mongolia, China. Based on the new materials, the name of two species in Eoptychopterina from China--Eoptychopterina elenae Ren and Krzeminski and Eoptychopterina gigantea Zhang--is sysnonymum junius.

  9. New insights into Troglotella incrustans WERNLI & FOOKES, 1992, a fascinating Upper Jurassic-Upper Cretaceous foraminifer

    Directory of Open Access Journals (Sweden)

    Felix Schlagintweit

    2012-05-01

    Full Text Available New data about the highly variable test morphology of the benthic foraminifer Troglotella incrustans WERNLI & FOOKES (Oxfordian-Lower Cenomanian are presented, permitting an emended species/genus diagnosis. This concerns mainly the existence of a large final chamber with fistulose extensions that may follow the uniserial or the irregular-branching test part. The way of life of T. incrustans (cryptoendolithic vs. euendolithic is discussed against the background of different existing models in the literature. The study is based on material (thin-sections and provided photographs mainly from the Upper Jurassic of Austria, Italy, Romania, Ukraine, and also the type-locality of France.

  10. Paleomagnetism of Jurassic-Cretaceous basalts from the Franz Josef Land Archipelago: tectonic implications

    Science.gov (United States)

    Abashev, Victor; Mikhaltsov, Nikolay; Vernikovsky, Valery

    2015-04-01

    New paleomagnetic data were obtained from a total of 158 oriented samples collected from the Jurassic magmatic complexes exposed on the Franz Joseph Land Archipelago (FJL). The field work was conducted during 2011 field season. Present study was focused on the tholeiitic basaltic lava flows that crop out on the Hooker Island. The samples were subjected to a detailed step-wise thermal demagnetization in temperatures up to 600 deg C or alternating field demagnetization with maximum filed up to 140 mT. Natural remanent magnetization (NRM) was measured with a 2G cryogenic magnetometer or a JR-6A spin-magnetometer housed in a magnetically shielded room at the Institute of Petroleum Geology and Geophysics, Siberian Branch of Russian Academy of Sciences. The main NRM carriers in the FJL samples are titanomagnetites with varying Ti-content. Magnetic remanence was unblocked in temperatures of 350-400 deg C. Some samples are characterized by unblocking temperatures of 560 deg C. The new paleomagnetic data were combined with those previously obtained from the early Cretaceous volcanics exposed on the FJL. A new mean paleomagnetic direction for the Jurassic rocks was calculated as D=78.3 deg, I=74.7 deg, a95=3.1 deg, k=194.3, N=13. A corresponding paleomagnetic pole is now located at Plat=62.1 deg; Plon=136.5 deg, A95=5.5 deg, K=63.6. New results suggest that the JFL occupied a significantly different position from that of the present day. However, in early Cretaceous the JFL was already located close to its present day position. We propose a rifting event between the North Barentz terrane (FJL and possibly Svalbard) and the counterpart of European tectonic domain. The rifting occurred during Early-Middle Jurassic. This event was accompanied by a significant shift of the FJL to the north-east for approximately 500 km. New results are in good agreement with a hypothesis that the FJL was passing over the Icelandic-Siberian hot spot during the Jurassic-Cretaceous time

  11. Paleoclimatology indicators of the Salt Wash member of the Upper Jurassic Morrison Formation near Jensen, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Medlyn, D.A. (Utah State Univ., Logan, UT (United States). Dept. of Geology); Bilbey, S.A. (Utah Field House of Natural History State Park, Vernal, UT (United States))

    1993-04-01

    The Upper Jurassic Morrison Formation has yielded one of the richest floras of the so-called transitional conifers'' of the Middle Mesozoic. Recently, a silicified axis of one of these conifers was collected from the Salt Wash member in essentially the same horizon as a previously reported partial Stegosaurus skeleton. In addition, two other axes of conifers were collected in the same immediate vicinity. Paleoecological considerations are extrapolated from the coniferous flora, vertebrate fauna and associated lithologies. Techniques of paleodendrology and relationships of extant/extinct environments are compared. The paleoclimatic conditions of the transitional conifers and associated dinosaurian fossils are postulated.

  12. Cap-shaped gastropods from Upper Jurassic and Lower Cretaceous deposits of northern East Siberia

    Science.gov (United States)

    Guzhov, A. V.; Zakharov, V. A.

    2015-09-01

    Cap-shaped gastropods are first identified in Upper Jurassic and Lower Cretaceous sections of northern East Siberia. They belong to three new genera of the subclass Pectinibranchia ( Boreioconus gen. nov., Nixepileolus gen. nov., and Taimyroconus gen. nov.), which are identified at the species level ( B. bojarkensis sp. nov., N. depressus sp. nov., T. zakharovi sp. nov.), and several species with the open nomenclature. The genus Taimyroconus attributed to the family Calyptraeidae is considered as an ancestral form of the genus Crepidula. The stratigraphic position of each taxon is determined for several sections. The facies confinement, habitat conditions, and ethology of defined genera are considered with the analysis of their geographic distribution.

  13. New fossil caddisfly from Middle Jurassic of Daohugou, Inner Mongolia, China (Trichoptera: Philopotamidae)

    Institute of Scientific and Technical Information of China (English)

    Meixia Wang; Yunyun Zhao; Dong Ren

    2009-01-01

    A new genus and new species, Juraphilopotamus lubricus gen. et sp. nov., from the Middle Jurassic Jiulongshan Formation of Daohugou, Inner Mongolia, China, is described and illustrated. It may be the first record of the family Philopotamidae in China, extending the geographic distribution of this family. A detailed description and illustration of the specimen along with a brief review of the fossil Philopotamidae are given. A proposal on dispersion and migration of Philopotamidae and problems of the paleoenvironment of the Daohugou beds are discussed.

  14. Dolomitization in Late Jurassic-Early Cretaceous Platform Carbonates (Berdiga Formation), Ayralaksa Yayla (Trabzon), NE Turkey

    Science.gov (United States)

    Yıldız, Merve; Ziya Kırmacı, Mehmet; Kandemir, Raif

    2017-04-01

    ABSTRACT Pontides constitute an E-W trending orogenic mountain belt that extends about 1100 km along the northern side of Turkey from the immediate east of Istanbul to the Georgian border at the east. Tectono-stratigraphically, the Pontides are divided into three different parts: Eastern, Central, and Western Pontides. The Eastern Pontides, including the studied area, comprise an area of 500 km in length and 100 km in width, extending along the southeast coast of the Black Sea from the Kizilirmak and Yesilirmak Rivers in the vicinity of Samsun to the Little Caucasus. This area is bordered by the Eastern Black Sea basin to the north and the Ankara-Erzincan Neotethyan suture zone to the south. The Late Jurassic-Early Cretaceous platform carbonates are widely exposed in E-W direction in the Eastern Pontides (NE Turkey). The Platform carbonates shows varying lithofacies changing from supratidal to platform margin reef laterally and vertically, and was buried until the end of Late Cretaceous. The studied Ayralaksa Yayla (Trabzon, NE Turkey) area comprises one of the best typical exposures of formation in northern zone of Eastern Pontides. In this area, the lower parts of the formation are pervasively dolomitized by fabric-destructive and fabric-preserving replacement dolomite which are Ca-rich and nonstoichiometric (Ca56-66Mg34-44). Replacement dolomites (Rd) are represented by D18O values of -19.0 to -4.2 (VPDB), D13C values of 4.4 to 2.1 \\permil (VPDB) and 87Sr/86Sr ratios of 0.70889 to 0.70636. Petrographic and geochemical data indicate that Rd dolomites are formed prior to compaction at shallow-moderate burial depths from Late Jurassic-Early Cretaceous seawater and/or partly modified seawater as a result of water/rock interaction and they were recrystallized at elevated temperatures during subsequent burial. In the subsequent diagenetic process during the Late Cretaceous when the region became a magmatic arc, as a result of interaction with Early Jurassic volcanic

  15. Oldest isotopically characterized fish otoliths provide insight to Jurassic continental climate of Europe

    Science.gov (United States)

    Patterson, William P.

    1999-03-01

    Large, shallow, epeiric seas and adjacent lagoons such as those described herein likely played a significant role in moderating Jurassic coastal and continental climate. Jurassic (Bathonian) ocean surface temperatures in Scotland have been calculated from δ18O(CaCO3) values of a suite of the oldest well-preserved fish otoliths analyzed to date. Otolith δ18O values range from -4.7‰ to -1.9‰ (Vienna Peedee belemnite, VPDB), while δ13C(CaCO3) values vary from -5.4‰ to +1.5‰ (VPDB), representing the oldest stable isotopic record of paleodiet, paleoecology, and fish migration to date. Using a global ocean δ18O(H2O) value of -1.0‰ (Vienna standard mean ocean water, VSMOW) for an ice-free Jurassic, fish species that migrated from estuarine to open marine water record time-averaged temperatures of 23 °C. Estuarine fish, assuming a similar temperature, record variation in δ18O(H2O) values from -3.7‰ to -2.0‰ (VSMOW). That significant mixing of fresh water and seawater occurred in the Jurassic in Scotland is in general agreement with data presented by others (molluscan fauna, lithostratigraphy, paleogeography, and paleocirculation models). The δ18O values and temperatures derived in this study correspond to the meteorologic and hydrologic parameters of a mid-latitude maritime climate with low seasonality, a mean temperature of 23 °C, and abundant precipitation and humidity. The δ18O(H2O) values calculated from estuarine fish indicate that rainfall must have a δ18O(H2O) value lower than -3.7‰ (VSMOW). Values of δ18O and δ13C suggest an environment hydrologically similar to that observed in the Everglades of south Florida or the estuaries of south Texas, both notable fish nurseries today. However, sea-surface temperatures were lower than those of modern Florida or Texas as evidenced by reduced evaporative enrichment of δ18O(H2O) values.

  16. JURASSIC SEDIMENTARY AND TECTONIC PROCESSES AT MONTAGNA GRANDE (TRAPANESE DOMAIN, WESTERN SICILY, ITALY

    Directory of Open Access Journals (Sweden)

    LUCA MARTIRE

    2004-03-01

    Full Text Available The Rosso Ammonitico of the Montagna Grande area is very interesting because of the great diversification in facies and thickness in three very closely situated sections. The Jurassic succession in this area is that typical of the Trapanese Domain. It starts with a thick pile of platform limestones (Inici Formation: Hettangian - Sinemurian that are overlain by typically condensed and commonly nodular pelagic limestones (Rosso Ammonitico: Middle Jurassic - lowermost Cretaceous. The good exposure of this succession in active quarries allows observation of sedimentological and palaeontological details and to improve the understanding of the Jurassic tectono-sedimentary evolution. The Rocca chi Parra quarry shows a stepped surface, with a relief of some metres, incised in the Inici Formation. It is covered by lenticular or wedge-shaped lithosomes a few metres-thick of highly condensed Rosso Ammonitico. It is interpreted as a slide scar along which a thin but extensive block of lithified platform limestones was detached and slid downslope. The Poggio Roccione quarry shows neptunian sills and collapse structures in the middle part of the Rosso Ammonitico that on the whole is thicker (about 12 m than at Rocca chi Parra. They indicate sea-floor instability probably due to seismic shocks with brittle to plastic behaviour of sediments depending on their coherence. The Montagna Grande outcrop shows an even thicker succession which includes a wedge of cherty limestones about 10 m thick intercalated between a lower and an upper Rosso Ammonitico calcareous unit. The features described in these three sections document a highly irregular sea-floor topography which in turn was controlled by several phases of extensional tectonics during Mid and Late Jurassic pelagic sedimentation. Structurally higher sectors closer to fault scarps were affected by a very condensed sedimentation, the opening of subvertical dykes and the triggering of large slides. Structurally

  17. New fossil mayflies (Insecta: Ephemeroptera) from the Middle Jurassic of Daohugou, Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    Jian-Dong Huang; Dong Ren; Nina D. Sinitshenkova; Chung-Kun Shih

    2008-01-01

    Jurassonurus amoenus, a new genus and species of Siphlonuridae s. l. is described from the Middle Jurassic Jiulongshan Formation of the Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China. The new species is established by more than 20 imago and subimago specimens in relatively good condition. Detailed description and illustration of the specimens along with a review of fossil Siphlonuridae s.l. are given. Comparing with two known dominant nymph species Fuyous gregarious Zhang and Kluge, 2007 and Shantous lacustri Zhang and Kluge, 2007 from the same locality, we could not find any relationship among them. The new species is another dominant species in Daohugou beds.

  18. Tracing biosignatures from the Recent to the Jurassic in sabkha-associated microbial mats

    Science.gov (United States)

    van der Land, Cees; Dutton, Kirsten; Andrade, Luiza; Paul, Andreas; Sherry, Angela; Fender, Tom; Hewett, Guy; Jones, Martin; Lokier, Stephen W.; Head, Ian M.

    2017-04-01

    Microbial mat ecosystems have been operating at the sediment-fluid interface for over 3400 million years, influencing the flux, transformation and preservation of carbon from the biosphere to the physical environment. These ecosystems are excellent recorders of rapid and profound changes in earth surface environments and biota as they often survive crisis-induced extreme paleoenvironmental conditions. Their biosignatures, captured in the preserved organic matter and the biominerals that form the microbialite rock, constitute a significant tool in understanding geobiological processes and the interactions of the microbial communities with sediments and with the prevailing physical chemical parameters, as well as the environmental conditions at a local and global scale. Nevertheless, the exact pathways of diagenetic organic matter transformation and early-lithification, essential for the accretion and preservation in the geological record as microbialites, are not well understood. The Abu Dhabi coastal sabkha system contains a vast microbial mat belt that is dominated by continuous polygonal and internally-laminated microbial mats across the upper and middle intertidal zones. This modern system is believed to be the best analogue for the Upper Jurassic Arab Formation, which is both a prolific hydrocarbon reservoir and source rock facies in the United Arab Emirates and in neighbouring countries. In order to characterise the processes that lead to the formation of microbialites we investigated the modern and Jurassic system using a multidisciplinary approach, including growth of field-sampled microbial mats under controlled conditions in the laboratory and field-based analysis of microbial communities, mat mineralogy and organic biomarker analysis. In this study, we focus on hydrocarbon biomarker data obtained from the surface of microbial mats actively growing in the intertidal zone of the modern system. By comparing these findings to data obtained from recently

  19. New fossil elaterids (Insect: Coleoptera: Polyphaga: Elateridae) from the Middle Jurassic of Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    Huali Chang; Yunyun Zhao; Dong Ren

    2009-01-01

    A new genus with a new species of fossil elaterid, Paraprotagrypnus superbus gen. et sp. nov., from the Middle Jurassic Jiulongshan Formation in Daohugou Village (N41°18.979', E119°14.318'), Shantou Township, Ningcheng County, Inner Mongolia, China is described and illustrated. The genus Paraprotagrypnus belongs to the family of Elateridae, subfamily of Protagrypninae and tribe of Protagrypnini. Some primitive characters of the new genus and new species shed light on the ages between the Jiulongshan Formation in Inner Mongolia and the Yixian Formation in the western Liaoning Province of China. The habitat of the new species is briefly discussed.

  20. New Jurassic Fossil True Bugs of the Pachymeridiidae (Hemiptera:Pentatomomorpha) from Northeast China

    Institute of Scientific and Technical Information of China (English)

    YAO Yunzhi; CAI Wanzhi; REN Dong

    2008-01-01

    Four new fossil genera and species of true bugs from the family Pachymeridiidae,Beipiaocoris multifurcus, Bellicoris mirabilis, Nitoculus regillus, and Viriosinervis stolidus, are described. New specimens were collected from the Middle and Upper Jurassic non-marine sedimentary strata from the Jiulongshan and Yixian Formations of northeast China. The species Karatavocoris asiatica Becker-Migdisova, 1963, which was considered to be a member of the family Coreidae is transferred to the Pachymeridiidae. A new map of all known and newly discovered fossil pachymeridiid localities is given. The diagnosis of the family is modified.

  1. Changes of taxonomical composition of Late Jurassic Early Cretaceous palynofloras of Bureya Basin,Russia

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The changes of taxonomical composition of the Late Jurassic-Early Cretaceous palynofloras are revealed,in the upper stream of Bureya River in Bureya Basin.The palynofloras are dominated as follows:the Berriasian one by ferns (Cyatheaceae,Dicksoniaceae,Osmundaceae), Classopollis and bisaccate pollen;the Valanginian-Hauterivian one by ferns (Cyatheaceae,Dicksoniaceae), Ginkgocycadophytus and bisaccate pollen;the Barremian one by ferns(Cyatheaceae,Dieksoniaceae);the Aptian one by ferns(Cyatheaceae,Dieksoniaceae,Gleicheniaceae)and Ginkgocycadophytus;and the Albian one by ferns(Schizaeaceae)and bisaccate pollen.In the Albian the floral diversity raises with the angiosperms appearing.

  2. Middle Jurassic continental biota and paleolandscape in the Dubinino locality (Sharypovo area, Krasnoyarsk krai)

    Science.gov (United States)

    Ivantsov, S. V.; Bystritskaya, L. I.; Krasnolutskii, S. A.; Lyalyuk, K. P.; Frolov, A. O.; Alekseev, A. S.

    2016-09-01

    On the basis of the lithological-facies analysis, it was established that deposits of the Upper Itat Subformation, comprising the Dubinino locality of the Middle Jurassic flora and insects (Sharypovo district, Krasnoyarsk krai), accumulated in alluvial and lacustrine and, to a lesser extent, floodplain environments (floodplain and alluvial fan facies). The occurrence of remains of insects, macroremains of flora, spores, and pollen allowed us to make a paleoreconstruction of an area with a strongly dissected relief: continental fresh-water reservoir (lake) with varying degree of overflow, surrounded by hills covered with gymnospermous and ginkgo forests.

  3. LATE JURASSIC AND EARLY CRETACEOUS AMMONITES FROM THE WEIMEI FORMATION IN GYANGZE, SOUTHERN TIBET

    Directory of Open Access Journals (Sweden)

    MASAHIKO TAKEI

    2004-03-01

    Full Text Available The Weimei Formation in southern Tibet is a shallow marine sequence accumulated in the northern margin of the Indian subcontinent. It has been dated as Tithonian based on ammonites such as Haplophylloceras strigile (Blanford, Berriasella sp. and Himalayites sp. Six ammonite specimens were found in the type locality of the Weimei Formation. They include Spiticeras (Spiticeras spitiense (Blanford, Berriasella sp. and Phylloceras sp. The occurrence of S. spitiense indicates that the ammonite-bearing portion is assignable to the Berriasian stage. The Jurassic/Cretaceous boundary possibly exists within the Weimei Formation.

  4. First records of crocodyle and pterosaur tracks in the Upper Jurassic of Portugal

    DEFF Research Database (Denmark)

    Mateus, Octavio; Milàn, Jesper

    2010-01-01

    The Upper Jurassic of Portugal has a rich vertebrate fauna well documented from both body and trace fossils. Although the occurrence of crocodyles and pterosaurs is well documented from body fossils, trace fossils from both groups were unknown until now. Here we describe an isolated crocodyle......-like track from Praia da Peralta and pterosaur tracks from the Kimmeridgian of Pedreira do Avelino, Sesimbra (Azoia Fm.) and Porto das Barcas, Lourinha (Lourinha Fm.). An enigmatic track suggests the possible presence of a small, tail-dragging tetrapod. Possible track-makers are suggested based on the known...

  5. An Upper Jurassic-Lower Cretaceous carbonate platform from the Vâlcan Mountains (Southern Carpathians, Romania): paleoenvironmental interpretation

    Science.gov (United States)

    Michetiuc, Mihai; Catincuţ, Camelia; Bucur, Ioan I.

    2012-02-01

    The results of a biostratigraphic and sedimentological study of the Upper Jurassic-Lower Cretaceous limestones cropping out in the southern sector of the Vâlcan Mountains in Romania are presented, including the definition of microfacies types, fossil assemblages and environmental interpretation. Six microfacies types (MFT 1-MFT 6) have been identified, each of them pointing to a specific depositional environment. The deposits are characteristic of a shallow carbonate platform. They contain normal marine or restricted marine facies deposited in low or high energy environments from the inner, middle and outer platform. The age attribution of these deposits (Late Jurassic to Berriasian-Valanginian-?Hauterivian, and Barremian) is based on foraminiferal and calcareous algae associations. The micropaleontological assemblage is exceptionally rich in the Vâlcan Mountains and brings new arguments for dating the Upper Jurassic-Lower Cretaceous limestones in this area.

  6. Shoreline Migration and Land Exposure of the SE Levant (Israel) During the Closure of the Neo-Tethys (Late Eocene and onward)

    Science.gov (United States)

    Gvirtzman, Zohar; Steinberg, Josh; Bar, Oded; Buchbinder, Binyamin; Zilberman, Ezra; Siman-Tov, Rimona; Calvo, Rani; Grossowicz, Lidia; Almogi-Labin, Ahuva; Rosensaft, Marcelo

    2010-05-01

    Since the Late Eocene, along with the closure of the Neo-Tethys Ocean, the paleogeography of the north Arabian Peninsula changed significantly. The uplift and exposure of the continental region, today occupying Iraq, Syria, Jordan, Israel, and Lebanon, disconnected the Mediterranean basin from the Mesopotamian basin. This changed the contours of Arabia and the shoreline that had previously extended from Egypt towards the Persian Gulf, changed its course northwards towards Turkey along the present day Mediterranean coasts. Reconstruction of the gradual land exposure and migration of the shoreline throughout the past 37 million years is important not only for the regional paleo-geography and paleo-oceanography, but also for the understanding of geodynamic processes that controlled the inland vertical motions south of the Arabia-Eurasia convergence zone. Israel is located in a key area where late Tertiary shorelines of the Levant continental margin can be traced. A series of abrasive platforms, capped by shallow marine sediments, extend along the western foothills of Israel and form stepped morphological surfaces. These surfaces can be traced all the way from the Negev desert in the south to Mt. Carmel in the north, mark the positions of the paleo-shorelines and record the uplift history of the mountainous backbone, which began in the late Eocene or early Oligocene. The present study reconstructs the late Tertiary shorelines from central Israel northwards, applying morphometric analysis of the foothills relief and subsurface analysis of stratigraphic sections preserved in low basins. We found a continuous abrasive platform of Middle Miocene to Pliocene age, which extends approximately at similar altitudes from the Judea hills to Mt. Carmel, indicating similar exposure history of these regions since the Middle Miocene. On the other hand, the initial exposure of the Judea hills, predated Mt. Carmel, by 20-25 my and may have started in the Late Eocene. During the

  7. Origins of Early Mesozoic granitoids and their enclaves from West Kunlun, NW China: implications for evolving magmatism related to closure of the Paleo-Tethys ocean

    Science.gov (United States)

    Wang, Chao; Liu, Liang; Korhonen, Fawna; Yang, Wen-Qiang; Cao, Yu-Ting; He, Shi-Ping; Zhu, Xiao-Hui; Liang, Wen-Tian

    2016-04-01

    Early Mesozoic granitoids and microgranular enclaves (MEs) are widespread in the West Kunkun, northwestern Tibetan plateau, and record the tectonic evolution of Eurasia-Tethys in this area. This study reports geochemistry, zircon U-Pb and Hf isotopic data for a suite of granitoids and their MEs from the Middle Triassic Bulunkou pluton (BP) and the Late Triassic Akazishan pluton (AP) from the West Kunlun. LA-ICP-MS U-Pb zircon dating of a sample from the BP host monzogranite and an enclave, as well as a AP monzogranite, yielded ages of 236 ± 2, 230 ± 7 and 208 ± 1 Ma, respectively. The BP monzogranite and its enclaves from the northwestern part of the West Kunlun are mainly weakly peraluminous granites characterised by relatively high Rb, Th, Rb/Sr (2.64-9.03) and HREE contents, and low Mg#, Sr/Y and negative Eu anomalies. Zircons from the BP monzogranite have ɛHf(t) values from -5.7 to -1.6. Zircons from enclaves of the BP show more variable ɛHf(t) values from -4.1 to 3.8. We consider that the BP granites are likely to have been formed by partial melting of metasedimentary rocks at shallow crustal depth, and their enclaves, composed of quartz + biotite + plagioclase + garnet + K-feldspar, are relics from the melting of a source at middle crustal depths. The AP host and its enclaves from the southeastern part of the West Kunlun have low Rb, Rb/Sr (0.15-1.90) and weakly negative Eu anomalies but high HREE contents indicating limited fractionation of plagioclase without residual garnet in their source. The inferred protolith is an intermediate igneous rock in the middle or lower crust. MEs hosted in the AP have high Mg# (39.7-45.0) and Nb and weakly negative Eu anomalies, as well as high Sr, P and Ti, corresponding to a medium-K basaltic rock, which may have originated from mixing of partial melting of metasomatised mantle wedge that has been modified by upwelling asthenospheric mantle and crustal melting in the deep source. Post-collisional southeasternward

  8. The Global Boundary Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic), Wine Haven, Yorkshire, UK

    Institute of Scientific and Technical Information of China (English)

    Christian Meister; Mark Hylton; Nicol Morton; Kevin Page; Greg D. Price; Martin Aberhan; Joachim Blau; Jean-Louis Dommergues; Susanne Feist-Burkhardt; Ernie A. Hailwood; Malcom Hart; Stephen P. Hesselbo; Mark W. Hounslow

    2006-01-01

    @@ Following votes by the Pliensbachian Working Group, the Jurassic Subcommission and the International Commission on Stratigraphy, IUGS ratified the proposed Global Boundary Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic) at the base of bed 73b in the Wine Haven section, Robin Hood's Bay, Yorkshire Coast, UK.

  9. An early bird from Gondwana: Paleomagnetism of Lower Permian lavas from northern Qiangtang (Tibet) and the geography of the Paleo-Tethys

    Science.gov (United States)

    Song, Peiping; Ding, Lin; Li, Zhenyu; Lippert, Peter C.; Yue, Yahui

    2017-10-01

    The origin of the northern Qiangtang block and its Late Paleozoic-Early Mesozoic drift history remain controversial, largely because paleomagnetic constraints from pre-Mesozoic units are sparse and of poor quality. In this paper, we provide a robust and well-dated paleomagnetic pole from the Lower Permian Kaixinling Group lavas on the northern Qiangtang block. This pole suggests that the northern Qiangtang block had a paleolatitude of 21.9 ± 4.7 °S at ca. 296.9 ± 1.9 Ma. These are the first volcanic-based paleomagnetic results from pre-Mesozoic rocks of the Qiangtang block that appear to average secular variation accurately enough to yield a well-determined paleolatitude estimate. This new pole corroborates the hypothesis, first noted on the basis of less rigorous paleomagnetic data, the presence of diamictites, detrital zircon provenance records, and faunal assemblages, that the northern Qiangtang block rifted away from Gondwana prior to the Permian. Previous studies have documented that the northern Qiangtang block accreted to the Tarim-North China continent by Norian time. We calculate a total northward drift of ca. 7000 km over ca. 100 myr, which corresponds to an average south-north plate velocities of ∼7.0 cm/yr. Our results do not support the conclusion that northern Qiangtang has a Laurasian affinity, nor that the central Qiangtang metamorphic belt is an in situ Paleo-Tethys suture. Our analysis, however, does not preclude paleogeographies that interpret the central Qiangtang metamorphic belt as an intra-Qiangtang suture that developed at southernly latitudes outboard of the Gondwanan margin. We emphasize that rigorous paleomagnetic data from Carboniferous units of northern Qiangtang and especially upper Paleozoic units from southern Qiangtang can test and further refine these paleogeographic interpretations.

  10. Triggers of Permo-Triassic boundary mass extinction in South China: The Siberian Traps or Paleo-Tethys ignimbrite flare-up?

    Science.gov (United States)

    He, Bin; Zhong, Yu-Ting; Xu, Yi-Gang; Li, Xian-Hua

    2014-09-01

    Assessment of the synchroneity between the Siberian Traps and the Permo-Triassic boundary (PTB) mass extinction has led to the proposition that the Siberian flood volcanism was responsible for the severest biotic crisis in the Phanerozoic. However, recent studies suggest that the Siberian Traps may have postdated the main extinction horizon. In this paper, we demonstrate, using stratigraphy, a time and intensity coincidence between PTB volcanic ash and the main extinction horizon. Geochemistry of the PTB volcanic ashes in five sections in South China indicates that they were derived from continental magmatic arc. Zircons extracted from the PTB volcanic ashes have negative εHf(t) (- 12.9 to - 2.0) and δ18O (6.8 to 10.9‰), consistent with an acidic volcanism and a crustal-derived origin, and therefore exclude a genetic link between the PTB mass extinction and the Siberian Traps. On the basis of spatial variation in the number of the PTB volcanic ash layers and the thickness of the ash layers in South China, we propose that the PTB volcanic ash may be related to Paleo-Tethys continental arc magmatism in the Kunlun area. Ignimbrite flare-up related to rapid plate subduction during the final assemblage of the Pangea super-continent may have generated a volcanic winter, which eventually triggered the collapse of ecosystem and ultimately mass extinction at the end of the Permian. The Siberian Traps may have been responsible for a greenhouse effect and so have been responsible for both a second pulse of the extinction event and Early Triassic ecological evolution.

  11. Reconstruction of Original SedimentaryProvince of the Jurassic in the Northwestern China%西北地区侏罗纪原始沉积区恢复

    Institute of Scientific and Technical Information of China (English)

    薛良清; 李文厚

    2000-01-01

    The Jurassic strata are widely distributed in the northwesternChina. The Early to early Middle Jurassic strata are major coal-bearing strata in the northwestern China that consist of sedimentary products of warm-humid climte,which are easily traced and correlated regionally. The late Middle to Late Jurassic strata are mainly composed of red beds, interbedded conglomerate and light-gray sandstones deposited in the alluvial and fluvial environments, showing paleoclimate changed from humid to dry features. In recent years, hydrocarbon exploration and researches in the Jurassic of NW China found the following facts:many present basin-margin areas often lack basinmarginal coarse-grain sediments of the Jurassic, while present tectonic uplift belts separating sedimentary basins are not present in some periods of the Jurassic or even whole Jurassic. Thus, it is necessary to reconstruct original sedimentary province of the Jurassic basins in NW China. Reconstruction of sedimentary province of the Jurassic in NW China is based on marginal sedimentary facies analysis, stratigraphic contact relationship analysis, paleocurrent system analysis, and tectonic/structural framework analysis. Marginal sedimentary facies analysis focuses on identifying alluvial fan and fluvial depositional systems that define sedimentary extent of basins. Stratigraphic contact relationship analysis is study on relationship between the residual Jurassic strata and underlying or overlaying strata because the relationship reflects depositional setting of the Jurassic strata and transform extent after the Jurassic deposition. Paleocurrent system analysis can help recognize relationship among remade basins at present. Identification of source area, shape and boundary of basins can be carried out on the basis of paleocurrent distribution. Tectonic/structural framework directly or indirectly affects deposition, sometimes are main factor to control sdimentary province and distribution of depositional systems

  12. Study of the Factors Affecting the Abundance of Organic Matter in Jurassic Carbonate Rocks in Qiangtang Basin, Tibet

    Institute of Scientific and Technical Information of China (English)

    文志刚; 胡明毅; 龚文平; 肖传桃

    2004-01-01

    Field and laboratory analyses of carbonate rock samples from the Qiangtang Basin,Tibet, indicate that carbonate source rocks are mainly developed in the Middle Jurassic Xiali Formation and Upper Jurassic Suowa Formation. Comprehensive studies showed that the Suowa Formation carbonate source rocks have a favorable hydrocarbon-generating potential. The abundance of organic matter in the carbonate rocks is controlled mainly by sedimentary environment and inorganic compounds in the rocks, which is higher in the restricted platform facies than in the open platform facies. Organic carbon contents decrease with increasing CaO contents in the source rocks.

  13. Lower limits of ornithischian dinosaur body size inferred from a new Upper Jurassic heterodontosaurid from North America.

    Science.gov (United States)

    Butler, Richard J; Galton, Peter M; Porro, Laura B; Chiappe, Luis M; Henderson, Donald M; Erickson, Gregory M

    2010-02-07

    The extremes of dinosaur body size have long fascinated scientists. The smallest (member of the basal dinosaur clade Heterodontosauridae, and is the first member of this clade to be described from North America. The craniodental anatomy and diminutive body size of Fruitadens suggest that this taxon was an ecological generalist with an omnivorous diet, thus providing new insights into morphological and palaeoecological diversity within Dinosauria. Late-surviving (Late Jurassic and Early Cretaceous) heterodontosaurids are smaller and less ecologically specialized than Early (Late Triassic and Early Jurassic) heterodontosaurids, and this ecological generalization may account in part for the remarkable 100-million-year-long longevity of the clade.

  14. New theropod, thyreophoran, and small sauropod tracks from the Middle Jurassic Bagå Formation, Bornholm, Denmark

    DEFF Research Database (Denmark)

    Milàn, Jesper

    2011-01-01

    Three new dinosaur tracks are described from the Middle Jurassic Bagå Formation of Bornholm, Denmark. The tracks are all preserved as natural casts on the underside of fluvial sandstone blocks originating from the old Hasle Klinkefabrik’s clay pit, now called Pyritsøen. The new tracks are from...... a medium-sized theropod, a thyreophoran, and a small sauropod. Together with a hyreophoran track and large sauropod tracks described in 2005, the Middle Jurassic dinosaur fauna of Bornholm now comprises theropods, two sizes of sauropods and at least one type of thyreophoran dinosaur. This is important...

  15. Jurassic animals and algae in the flooring of Our Lady of Sorrows Church in Poznań

    Directory of Open Access Journals (Sweden)

    Antczak Mateusz

    2015-12-01

    Full Text Available The flooring of Our Lady of Sorrows Church in Poznań is made of Jurassic rocks from the Świętokrzyskie Mountains (also known as Holy Cross Mountains and contain abundant marine invertebrate fossils: sponges, bivalves, brachiopods, various families of cephalopods, etc. Some of them can be identified to the genus level. The fossils make it possible to describe the environment and ecosystem of the Jurassic sea and biostratigraphy of the sediment. There are also some significant inorganic structures, which suggest post-diagenetic tectonic movements.

  16. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds.

    Science.gov (United States)

    Godefroit, Pascal; Cau, Andrea; Dong-Yu, Hu; Escuillié, François; Wenhao, Wu; Dyke, Gareth

    2013-06-20

    The recent discovery of small paravian theropod dinosaurs with well-preserved feathers in the Middle-Late Jurassic Tiaojishan Formation of Liaoning Province (northeastern China) has challenged the pivotal position of Archaeopteryx, regarded from its discovery to be the most basal bird. Removing Archaeopteryx from the base of Avialae to nest within Deinonychosauria implies that typical bird flight, powered by the forelimbs only, either evolved at least twice, or was subsequently lost or modified in some deinonychosaurians. Here we describe the complete skeleton of a new paravian from the Tiaojishan Formation of Liaoning Province, China. Including this new taxon in a comprehensive phylogenetic analysis for basal Paraves does the following: (1) it recovers it as the basal-most avialan; (2) it confirms the avialan status of Archaeopteryx; (3) it places Troodontidae as the sister-group to Avialae; (4) it supports a single origin of powered flight within Paraves; and (5) it implies that the early diversification of Paraves and Avialae took place in the Middle-Late Jurassic period.

  17. Didactyl tracks of paravian theropods (Maniraptora from the ?Middle Jurassic of Africa.

    Directory of Open Access Journals (Sweden)

    Alexander Mudroch

    Full Text Available BACKGROUND: A new dinosaur tracksite from ?Middle Jurassic sediments of the Irhazer Group on the plains of Agadez (Rep. Niger, northwest Africa revealed extraordinarily well preserved didactyl tracks of a digitigrade bipedal trackmaker. The distinct morphology of the pes imprints indicates a theropod trackmaker from a paravian maniraptoran closely related to birds. METHODOLOGY/PRINCIPAL FINDINGS: The early age and the morphological traits of the tracks allow for description of the new ichnotaxon Paravipus didactyloides. A total of 120 tracks are assigned to 5 individual trackways. The 'medium-sized' tracks with an average footprint length of 27.5 cm and footprint width of 23.1 cm are deeply imprinted into the track bearing sandstone. CONCLUSIONS/SIGNIFICANCE: A comparison with other didactyl tracks gives new insights into the foot morphology of advanced maniraptoran theropods and contributes to knowledge of their evolutionary history. The new ichnotaxon takes an important position in the ichnological fossil record of Gondwana and the mid-Jurassic biota worldwide, because it is among the earliest known records of paravian maniraptorans and of didactyl theropod tracks from Africa.

  18. Taphonomy and paleoecology inferences of vertebrate ichnofossils from Guará Formation (Upper Jurassic), southern Brazil

    Science.gov (United States)

    Dentzien-Dias, Paula C.; Schultz, Cesar L.; Bertoni-Machado, Cristina

    2008-03-01

    In southern Brazil, the eolian facies of the Guará Formation (Late Jurassic) reveal footprints and trackways of vertebrates (dinosaurs), as well as burrows made by small vertebrates. All the footprints and trackways are preserved in dunes and sand sheets. The footprints made in the sand sheets are not well preserved due to intense trampling and can be distinguished only by the deformation of the sandstone laminations. In some cases it is possible to see this deformation in plan and in section. Tracks of theropods, ornithopods and middle-sized sauropods are present. Two footprints preserved in the foreset of a paleodune permitted recognition of slide structures and identification of the trackmaker, a theropod. Burrows horizontally across the foresets were found at this same paleodune. Ribbons of massive sandstone - interpreted as the partial filling of the base of the burrows - covered by little blocks of stratified sandstone - suggest the collapse of the burrow roof inward. There are no body fossils in the Guará Formation, consequently the preservation of these tracks provides unique evidence of widespread dinosaurs activity in southern Brazil near the end of the Jurassic.

  19. JURASSIC HERITAGE OF PORTUGAL: STATE OF THE ART AND OPEN PROBLEMS

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    MARIA HELENA HENRIQUES

    2004-03-01

    Full Text Available The aim of this work is to present a general view on the situation of Jurassic sites outcropping in Portugal, in particular those located in the Lusitanian Basin, which represent geosites with heritage value. The legal instruments on geoconservation are generically presented, and they happen to be designed for Natural Heritage deeply confused with the Biological Heritage. No specific law for geological values exist in Portugal, but the general law on Natural Conservation has allowed the protection of five geosites of national relevance as Natural Monuments. They correspond to a small area when compared to the whole national area of Protected Sites, and they all correspond to dinosaur tracksites of Jurassic and Cretaceous age. Geosites of regional relevance have been also protected using municipal laws and they show important public use, sometimes giving rise to reference museums and to continuous pedagogical actions. On the other hand, geosites of international relevance for its stratigraphic value (the Bajocian GSSP at Cabo Mondego section, the candidate to the Toarcian GSSP at Peniche section have no formal protection and classification according to the Portuguese laws. They remain safe because they are located on the coast, which is protected due to other environmental laws. Their integration in a supra-national framework supported by UNESCO is obviously recommended and it would be of great impact among the national institutions with formal responsibilities on the Natural Heritage.

  20. Late Triassic - Early Jurassic successions of the Atuel depocenter: sequence stratigraphy and tectonic controls

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    Silvia Lanés

    2008-12-01

    Full Text Available Biostratigraphic correlations of the Late Triassic - Early Jurassic successions of the Atuel depocenter allowed determining the accommodation changes and the possible tectonic controls on sedimentation. The Rhaetian - late Early Sinemurian deposits contain facies of slope-type fan deltas, braided fluvial systems and low sinuosity rivers with alternate bars deposited during a synrift phase. The late Early Sinemurian - Toarcian series host facies of intermediate (Gilbert to shelf type fan deltas, braided and low sinuosity fluvial systems, wave-dominated estuaries, transgressive storm-dominated and turbidite-influenced marine shelves which record the sag phase. According to different criteria two stratigraphic schemes are proposed, the first one considering tectosedimentary units (TSU and the second one using "Exxon-like" sequences. In the first scheme the synrift TSU matches the actual Precuyo Mesosequence and the sag TSU is partly equivalent to the Cuyo Mesosequence, mainly keeping the current mesosequence scheme for the Neuquén basin but assigning the fandeltaic deposits to the Precuyo Mesosequence. The second sequence scheme considers the whole Late Triassic - Early Jurassic succession as a part of the Cuyo Mesosequence, where the synrift deposits composes the detached lowstand system tract (LST and most of the sag deposits makes the transgressive system tract (TST. The basal sequence boundary does not crop out, the flooding surface at the TST base and the maximum flooding surface at the TST top are respectively marked by the lowest estuarine levels and by black shales with suboxic-compatible bivalves (Bositra sp..

  1. Base level change and depositional filling response of Jurassic in the Qiangtang Basin of Tibet

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The base level during the deposition of Jurassic in the Qiangtang Basin shows a complete cycle from rising to falling. The base level change is closely connected with tectonic evolution of the basin,especially connected with Bangonghu-Nujiang ocean evolution process in the formation and evolution of the basin. It is also affected by climate. The Jurassic strata correspond to a long-term base level cycle sequence. The sequence is in fact a non-complete symmetrical cycle,consisting of rising hemicycle and falling hemicycle. It can be divided into 6 intermediate-term base level cycle sequences,including 2 carbonate sequences,3 mixture sedimentary sequences of carbonate and clastic rocks and one clastic sedimentary sequence. Depositional filling characteristics during base level change show that Bangonghu-Nujiang ocean spreads in Toarcian-Bajocian ages,and is at the height of spreading of Bangonghu-Nujiang ocean in Bathonian-Oxfordian ages. In that process,sea area became smaller because of the dry climate. Eventually,marine depositional filling is ended with the subduction and collision of Bangonghu-Nujiang ocean.

  2. Bird-like anatomy, posture, and behavior revealed by an early jurassic theropod dinosaur resting trace

    Science.gov (United States)

    Milner, A.R.C.; Harris, J.D.; Lockley, M.G.; Kirkland, J.I.; Matthews, N.A.

    2009-01-01

    Background: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. Methodology/Principal Findings: Here we describe a well-preserved theropod trackway in a Lower Jurassic (???198 millionyear- old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. Conclusions/Significance: The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.

  3. FORAMINIFERAL CHARACTERISATION OF MID-UPPER JURASSIC SEQUENCES IN THE WESSEX BASIN (UNITED KINGDOM

    Directory of Open Access Journals (Sweden)

    MELISSA J. OXFORD

    2004-03-01

    Full Text Available The use of foraminifera in the characterisation of sequences (systems tracts, maximum flooding surfaces, etc. has developed over the last decade. Much of this work has been based in the Cenozoic successions of the Gulf of Mexico, although there is a growing application of such data in the Middle East and the North Sea Basin. The easiest surface to characterise has been the maximum flooding surface with its high diversity and high(er abundance faunas; the characterisation of individual systems tracts has been less successful. Using the well-known mid-Upper Jurassic successions of the Dorset coastal sections, we have investigated a number of high resolution (parasequences for their foraminiferal content. Using data of foraminiferal diversity and standing crops from a range of modern substrates we have investigated the potential faunas available after deposition, taphonomy, compaction, groundwater dissolution and modern weathering. By understanding the processes involved we have identified the key foraminiferal features of typical mid-Upper Jurassic sequences and indicated how this work may help in the correlation of successions in North Dorset and Normandy.

  4. Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace

    Science.gov (United States)

    Milner, Andrew R. C.; Harris, Jerald D.; Lockley, Martin G.; Kirkland, James I.; Matthews, Neffra A.

    2009-01-01

    Background Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. Methodology/Principal Findings Here we describe a well-preserved theropod trackway in a Lower Jurassic (∼198 million-year-old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. Conclusions/Significance The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods. PMID:19259260

  5. Ammonoid discoveries in the Antimonio Formation, Sonora, Mexico: new constraints on the Triassic Jurassic boundary

    Science.gov (United States)

    González-León, C. M.; Stanley, G. D.; Taylor, D. G.

    2000-11-01

    The Triassic-Jurassic systemic boundary was recently reported in the middle part of the Antimonio Formation, northwestern Sonora, where five informal sedimentary packages were delineated and characteristic ammonoid faunas were used to establish age control within the succession. The boundary was suggested to lie within the middle part of the 24 m-thick package 4, in relatively unfossiliferous and organic-rich, laminated clay-silt mudstone. Despite the absence of diagnostic Hettangian fossils above the postulated boundary interval, its existence was predicted on characteristic uppermost Triassic Crickmayi Zone Choristoceras ammonoids occurring below in package 3 and upper Hettangian to lower Sinemurian (Badouxia Zone) ammonoids found above in package 5. Recent field investigations yielded new ammonoids of the uppermost Triassic Crickmayi Zone, which are described herein. They are assigned to Choristoceras cf. C. nobile Mojsisovics and Rhabdoceras cf. R. suessi Hauer. These characteristic ammonoids occur within the middle and top of package 4. Their discovery along with other stratigraphic evidence necessitates a revision of the boundary and recognition of a previously unrealized unconformity at the Triassic-Jurassic boundary in Sonora. A revised sea-level curve is necessary to account for these new stratigraphic and paleontological findings.

  6. Bird-like anatomy, posture, and behavior revealed by an early jurassic theropod dinosaur resting trace.

    Directory of Open Access Journals (Sweden)

    Andrew R C Milner

    Full Text Available BACKGROUND: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe a well-preserved theropod trackway in a Lower Jurassic ( approximately 198 million-year-old lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. CONCLUSIONS/SIGNIFICANCE: The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.

  7. The first elateroid beetles (Coleoptera: Polyphaga: Elateroidea) from the Upper Jurassic of Australia.

    Science.gov (United States)

    Oberprieler, Rolf G; Ashman, Lauren G; Frese, Michael; Ślipiński, Adam

    2016-08-03

    The first elateroid fossils from the Upper Jurassic Talbragar Fish Bed in Australia are described and illustrated. Wongaroo amplipectorale gen. et sp. n., based on two specimens, is placed in the family Cerophytidae due to its convex, posteriorly weakly angled and laterally carinate pronotum obscuring the head in dorsal view, its relatively long, pointed elytra and slender legs, its 9-striate elytra with deep basal pits and the absence of metacoxal plates. Beattieellus jurassicus gen. et sp. n., described from one specimen, possesses the acutely angled pronotum without a carina on the posterolateral angles and the ventral click apparatus typical of Eucnemidae and is classified in this family. Assignment of it to a eucnemid subfamily is impossible because of the insufficient preservation of relevant characters in the fossil. Four other elateroid fossils, possibly representing eucnemids and elaterids, are illustrated and briefly described but not named, due to their insufficient preservation. These fossils represent the first of their kind in Australia and in the Southern Hemisphere, and Beattieellus is also the oldest eucnemid fossil known and extends the fossil record of Eucnemidae into the Upper Jurassic. The discovery of elateroid fossils in the Talbragar Fish Bed adds to the coleopteran diversity of this ancient lake ecosystem, indicating that it was well wooded and provided suitable habitats of rotten wood for the development of the larvae of these taxa.

  8. Structural complexity at and around the Triassic-Jurassic GSSP at Kuhjoch, Northern Calcareous Alps, Austria

    Science.gov (United States)

    Palotai, M.; Pálfy, J.; Sasvári, Á.

    2017-02-01

    One of the key requirements for a Global Stratotype Section and Point (GSSP) is the absence of tectonic disturbance. The GSSP for the Triassic-Jurassic system boundary was recently defined at Kuhjoch, Northern Calcareous Alps, Austria. New field observations in the area of the Triassic-Jurassic boundary GSSP site demonstrate that the overturned, tight, and almost upright Karwendel syncline was formed at semibrittle deformation conditions, confirmed by axial planar foliation. Tight to isoclinal folds at various scales were related to a tectonic transport to the north. Brittle faulting occurred before and after folding as confirmed by tilt tests (the rotation of structural data by the average bedding). Foliation is ubiquitous in the incompetent units, including the Kendlbach Formation at the GSSP. A reverse fault (inferred to be formed as a normal fault before folding) crosscuts the GSSP sections, results in the partial tectonic omission of the Schattwald Beds, and thus makes it impossible to measure a complete and continuous stratigraphic section across the whole Kendlbach Formation. Based on these observations, the Kuhjoch sections do not fulfil the specific requirement for a GSSP regarding the absence of tectonic disturbances near boundary level.

  9. A large and complete Jurassic geothermal field at Claudia, Deseado Massif, Santa Cruz, Argentina

    Science.gov (United States)

    Guido, Diego M.; Campbell, Kathleen A.

    2014-04-01

    Late Jurassic geothermal deposits at Claudia, Argentinean Patagonia, are among the largest (40 km2) and most varied in the Deseado Massif, a 60,000 km2 volcanic province hosting precious metals (Au, Ag) mineralization generated during diffuse back arc spreading and opening of the South Atlantic Ocean. Both siliceous sinter and travertine occur in the same stratigraphic sequence. Deposits range from those interpreted as fluvially reworked hydrothermal silica gels, to extensive apron terraces, to a clustering of high-temperature subaerial vent mounds. Paleoenvironmentally diagnostic textures of sinters include wavy laminated, bubble mat and nodular fabrics, and for travertines comprise fossil terracette rims, wavy laminated, bubble mat, spherulitic, oncoidal, and peloidal fabrics. Of special note is the presence of relatively large (to 25 cm high), inferred subaqueous "Conophyton" structures in travertines, which serve as analogs for some Precambrian stromatolites and imply the presence of relatively deep pools maintained by voluminous spring discharges. The Claudia geothermal field is geographically and geologically linked to the Cerro Vanguardia epithermal project (total resource of ~ 7.8 million ounces Au equivalent) via proximity, similar veins, and structural linkages, making it an especially large and relevant prospect for the region. The combined Claudia-Cerro Vanguardia hydrothermal system likely represents a fortuitous alignment of focused fluid flow and structure conducive to forming a giant epithermal ore deposit, with respect to size, ore concentration and potentially duration, in the Late Jurassic of Patagonia.

  10. The bivalve Anopaea (Inoceramidae) from the Upper Jurassic-lowermost Cretaceous of Mexico

    Science.gov (United States)

    Zell, Patrick; Crame, J. Alistair; Stinnesbeck, Wolfgang; Beckmann, Seija

    2015-07-01

    In Mexico, the Upper Jurassic to lowermost Cretaceous La Casita and coeval La Caja and La Pimienta formations are well-known for their abundant and well-preserved marine vertebrates and invertebrates. The latter include conspicuous inoceramid bivalves of the genus Anopaea not formally described previously from Mexico. Anopaea bassei (Lecolle de Cantú, 1967), Anopaea cf. stoliczkai (Holdhaus, 1913), Anopaea cf. callistoensis Crame and Kelly, 1995 and Anopaea sp. are rare constituents in distinctive Tithonian-lower Berriasian levels of the La Caja Formation and one Tithonian horizon of the La Pimienta Formation. Anopaea bassei was previously documented from the Tithonian of central Mexico and Cuba, while most other members of Anopaea described here are only known from southern high latitudes. The Mexican assemblage also includes taxa which closely resemble Anopaea stoliczkai from the Tithonian of India, Indonesia and the Antarctic Peninsula, and Anopaea callistoensis from the late Tithonian to ?early Berriasian of the Antarctic Peninsula. Our new data expand the palaeogeographical distribution of the high latitude Anopaea to the Gulf of Mexico region and substantiate faunal exchange, in the Late Jurassic-earliest Cretaceous, between Mexico and the Antarctic Realm.

  11. Geochemical characteristics of fossil Solenites murrayana cuticles from the Jurassic in Lanzhou, northwest China

    Energy Technology Data Exchange (ETDEWEB)

    Sun, B.N.; Yan, D.F.; Xie, S.P.; Shi, Y.J.; Zhang, C.J.; Lin, Z.C. [Lanzhou University, Lanzhou (China)

    2006-07-01

    Through geochemical analysis on cuticles of the Jurassic fossil Solenites murrayuna L. et H. from the Yaojie Coalfield in Lanzhou, northwest China, and by comparison of geochemical features with its nearest living equivalent, Ginkgo biloba, we show that the characteristics of organic matter of the fossil plant cuticles accord with evolutionary features of asphalt in oil formation. The content analysis of organic matter indicates that the geochemistry is equivalent to rotten mud-sapropel humus types from Mesozoic and Cenozoic source rock in China. Some analysis data of organic matter indicate that Solenites murrayana cuticles are in a low mature stage, which coincides with the hydrocarbon generation model of cutinite in coal. Moreover, distribution features of soluble organic matter of cuticles show that fossil plant cuticles have a definite action in forming terrestrial high-wax oil, which has testified the contribution of high plants to waxness. The present study proves that Ginkgophytes abundant in the Jurassic were a high potential plant in the formation of coal-bed hydrocarbon.

  12. The rediscovery and redescription of the holotype of the Late Jurassic turtle Plesiochelys etalloni

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    Jérémy Anquetin

    2014-02-01

    Full Text Available Plesiochelyidae are a major component of Late Jurassic shallow marine environments throughout Europe. However, the taxonomy of plesiochelyid turtles is rather confused. Over the years, many taxa have been synonymized with Plesiochelys etalloni, one of the first described species. However, the holotype of P. etalloni (and only specimen known from Lect, the type locality was lost for more than 150 years. This specimen has been recently rediscovered in the collections of the Musée d’archéologie du Jura in Lons-le-Saunier, France. For the first time since its original description in 1857, the holotype of P. etalloni is redescribed and compared to relevant material. The taxonomic status of this taxon is revised accordingly. Based on the morphology of the newly rediscovered holotype and on a reassessment of specimens from Solothurn (Switzerland, the species P. solodurensis, P. sanctaeverenae and P. langii are synonymized with P. etalloni. Known skull-shell associations for P. etalloni are re-evaluated in light of the new morphological information available since the rediscovery of this holotype specimen. Finally, we confirm that Plesiochelys is represented by a single species in the Late Jurassic of the Jura Mountains.

  13. A giant spider from the Jurassic of China reveals greater diversity of the orbicularian stem group

    Science.gov (United States)

    Selden, Paul A.; Shih, ChungKun; Ren, Dong

    2013-12-01

    A large female spider, Nephila jurassica, was described from Middle Jurassic strata of north-east China and placed in the modern genus Nephila (family Nephilidae) on the basis of many morphological similarities, but, as with many ancient fossils, the single specimen lacked synapomorphies of the family (Selden et al. 2011). In order to test the placement within the nephilid phylogenetic tree, Kuntner et al. (2013) calibrated the molecular phylogeny using N. jurassica in three different scenarios based on inferred mitochondrial substitution rates. They concluded that N. jurassica fitted better as a stem orbicularian than a nephilid. Now, a giant male spider has been discovered at the same locality that yielded N. jurassica. The two sexes are considered conspecific based on their similar morphological features, size, and provenance. The male cannot be accommodated in Nephilidae because of its pedipalp morphology, so the new genus Mongolarachne and family Mongolarachnidae are erected for the species. Comparison with possibly related families show that Mongolarachnidae is most likely on the orbicularian stem, close to other cribellate orbicularians (e.g., Deinopoidea), which suggests a greater diversity of cribellate orbicularians during the Middle Jurassic.

  14. Upper Jurassic to Lower Cretaceous(?) synorogenic sedimentary rocks in the southern Spring Mountains, Nevada

    Science.gov (United States)

    Carr, Michael D.

    1980-08-01

    A newly recognized sequence of Upper Jurassic to Lower Cretaceous(?) terrigenous rocks in the Good-springs district, Nevada, was deposited during the emplacement of the Contact thrust plate. Two facies are recognized: (1) interbedded conglomerate and sandstone derived from Mesozoic igneous and terrigenous platform rocks and (2) interbedded carbonate and sandstone-clast conglomerate, quartz sandstone, and red shale. No igneous detritus occurs in the facies with carbonate-clast conglomerate. Carbonate clasts could only have been derived from the Paleozoic carbonate sequence, which was exposed in the area by latest Jurassic to earliest Cretaceous thrusting. The age of rocks from a volcanic unit within the synorogenic sequence was determined radiometrically to be 150 ± 10 m.y. (K-Ar on biotite). The sequence was deposited disconformably on deeply eroded rocks of the early Mesozoic platform and ultimately overridden from the west by the Contact thrust plate. Information from the sequence corroborates previously reported regional data regarding the timing and nature of the Contact-Red Springs thrust event. *Present address: U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025

  15. Marine ecosystem resilience during extreme deoxygenation: the Early Jurassic oceanic anoxic event.

    Science.gov (United States)

    Caswell, Bryony A; Frid, Christopher L J

    2017-01-01

    Global warming during the Early Jurassic, and associated widespread ocean deoxygenation, was comparable in scale with the changes projected for the next century. This study quantifies the impact of severe global environmental change on the biological traits of marine communities that define the ecological roles and functions they deliver. We document centennial-millennial variability in the biological trait composition of Early Jurassic (Toarcian) seafloor communities and examine how this changed during the event using biological traits analysis. Environmental changes preceding the global oceanic anoxic event (OAE) produced an ecological shift leading to stressed benthic palaeocommunities with reduced resilience to the subsequent OAE. Changes in traits and ecological succession coincided with major environmental changes; and were of similar nature and magnitude to those in severely deoxygenated benthic communities today despite the very different timescales. Changes in community composition were linked to local redox conditions whereas changes in populations of opportunists were driven by primary productivity. Throughout most of the OAE substitutions by tolerant taxa conserved the trait composition and hence functioning, but periods of severe deoxygenation caused benthic defaunation that would have resulted in functional collapse. Following the OAE recovery was slow probably because the global nature of the event restricted opportunities for recruitment from outside the basin. Our findings suggest that future systems undergoing deoxygenation may initially show functional resilience, but severe global deoxygenation will impact traits and ecosystem functioning and, by limiting the species pool, will slow recovery rates.

  16. A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs.

    Science.gov (United States)

    Pol, Diego; Rauhut, Oliver W M

    2012-08-22

    Abelisaurids are a clade of large, bizarre predatory dinosaurs, most notable for their high, short skulls and extremely reduced forelimbs. They were common in Gondwana during the Cretaceous, but exceedingly rare in the Northern Hemisphere. The oldest definitive abelisaurids so far come from the late Early Cretaceous of South America and Africa, and the early evolutionary history of the clade is still poorly known. Here, we report a new abelisaurid from the Middle Jurassic of Patagonia, Eoabelisaurus mefi gen. et sp. nov., which predates the so far oldest known secure member of this lineage by more than 40 Myr. The almost complete skeleton reveals the earliest evolutionary stages of the distinctive features of abelisaurids, such as the modification of the forelimb, which started with a reduction of the distal elements. The find underlines the explosive radiation of theropod dinosaurs in the Middle Jurassic and indicates an unexpected diversity of ceratosaurs at that time. The apparent endemism of abelisauroids to southern Gondwana during Pangean times might be due to the presence of a large, central Gondwanan desert. This indicates that, apart from continent-scale geography, aspects such as regional geography and climate are important to reconstruct the biogeographical history of Mesozoic vertebrates.

  17. Fossil evidence on evolution of inner ear cochlea in Jurassic mammals.

    Science.gov (United States)

    Luo, Zhe-Xi; Ruf, Irina; Schultz, Julia A; Martin, Thomas

    2011-01-07

    The coiled cochlea is a key evolutionary innovation of modern therian mammals. We report that the Late Jurassic mammal Dryolestes, a relative to modern therians, has derived bony characteristics of therian-like innervation, but its uncoiled cochlear canal is less derived than the coiled cochlea of modern therians. This suggests a therian-like innervation evolved before the fully coiled cochlea in phylogeny. The embryogenesis of the cochlear nerve and ganglion in the inner ear of mice is now known to be patterned by neurogenic genes, which we hypothesize to have influenced the formation of the auditory nerve and its ganglion in Jurassic therian evolution, as shown by their osteological correlates in Dryolestes, and by the similar base-to-apex progression in morphogenesis of the ganglion in mice, and in transformation of its canal in phylogeny. The cochlear innervation in Dryolestes is the precursory condition in the curve-to-coil transformation of the cochlea in mammalian phylogeny. This provides the timing of the evolution, and where along the phylogeny the morphogenetic genes were co-opted into patterning the cochlear innervation, and the full coiling of the cochlea in modern therians.

  18. Jurassic-Early Cretaceous Gondwanan homoxylous woods: a nomenclatural revision of the genera with taxonomic notes.

    Science.gov (United States)

    Bamford, M K.; Philippe, M

    2001-04-01

    The homoxylous fossil woods occurring in the Gondwanan continents of South America, Australia, Africa, India and Antarctica during the Jurassic and Early Cretaceous period are considered here. Original descriptions of the genera and wherever possible, the type material, have been consulted. Applying the rules of the International Code of Botanical Nomenclature, the generic names of the homoxylous woods have been revised from a nomenclatural point of view. According to this review, out of 31 generic names used for woods from the given time interval and area, 6 are illegitimate later nomenclatural synonyms, 1 is a later homonym, and 5 can be considered as taxonomical synonyms. Moreover, 9 genera have been used erroneously. We propose one new generic name (Protaxodioxylon n. gen.) and elsewhere we will propose for conservation, with a conserved type one of the illegitimate names and one of the taxonomic synonyms. As a result, we consider that there are only eighteen generic names correctly quoted for the Jurassic-Early Cretaceous of Gondwana, and we provide a taxonomic key for the corresponding genera. This revision is the first step in systematically comparing northern and southern hemisphere woods.

  19. Petrology and geochemistry of mafic magmatic rocks from the Sarve-Abad ophiolites (Kurdistan region, Iran): Evidence for interaction between MORB-type asthenosphere and OIB-type components in the southern Neo-Tethys Ocean

    Science.gov (United States)

    Saccani, Emilio; Allahyari, Khalil; Rahimzadeh, Bahman

    2014-05-01

    The Sarve-Abad (Sawlava) ophiolites crop out in the Main Zagros Thrust Zone and represent remnants of the Mesozoic southern Neo-Tethys Ocean that was located between the Arabian shield and Sanandaj-Sirjan continental block. They consist of several incomplete ophiolitic sequences including gabbroic bodies, a dyke complex, and pillow lava sequences. These rocks generally range from sub-alkaline to transitional character. Mineral chemistry and whole-rock geochemistry indicate that they have compositions akin to enriched-type mid-ocean ridge basalts (E-MORB) and plume-type MORB (P-MORB). Nonetheless, the different depletion degrees in heavy rare earth elements (HREE), which can be observed in both E-MORB like and P-MORB like rocks enable two main basic chemical types of rocks to be distinguished as Type-I and Type-II. Type-I rocks are strongly depleted in HREE (YbN 9.0). Petrogenetic modeling shows that Type-I rocks originated from 7 to 16% polybaric partial melting of a MORB-type mantle source, which was significantly enriched by plume-type components. These rocks resulted from the mixing of variable fractions of melts generated in garnet-facies and the spinel-facies mantle. In contrast, Type-II rocks originated from 5 to 8% partial melting in the spinel-facies of a MORB-type source, which was moderately enriched by plume-type components. A possible tectono-magmatic model for the generation of the southern Neo-Tethys oceanic crust implies that the continental rift and subsequent oceanic spreading were associated with uprising of MORB-type asthenospheric mantle featuring plume-type component influences decreasing from deep to shallow mantle levels. These deep plume-type components were most likely inherited from Carboniferous mantle plume activity that was associated with the opening of Paleo-Tethys in the same area.

  20. The Jurassic of Denmark and Greenland: Sedimentology and sequence stratigraphy of the Bryne and Lulu Formations, Middle Jurassic, northern Danish Central Graben

    Directory of Open Access Journals (Sweden)

    Andsbjerg, Jan

    2003-10-01

    Full Text Available The Middle Jurassic Bryne and Lulu Formations of the Søgne Basin (northern part of the Danish Central Graben consist of fluvially-dominated coastal plain deposits, overlain by interfingering shoreface and back-barrier deposits. Laterally continuous, mainly fining-upwards fluvial channel sandstones that locally show evidence for tidal influence dominate the alluvial/coastal plain deposits of the lower Bryne Formation. The sandstones are separated by units of fine-grained floodplain sediments that show a fining-upwards - coarsening-upwards pattern and locally grade into lacustrine mudstones. A regional unconformity that separates the lower Bryne Formation from the mainly estuarine upper Bryne Formation is defined by the strongly erosional base of a succession of stacked channel sandstones, interpreted as the fill of a system of incised valleys. Most of the stacked channel sandstones show abundant mud laminae and flasers, and rare herringbone structures, suggesting that they were deposited in a tidal environment, probably an estuary. Several tens of metres of the lower Bryne Formation may have been removed by erosion at this unconformity. The estuarine channel sandstone succession is capped by coal beds that attain a thickness of several metres in the western part of the Søgne Basin, but are thin and poorly developed in the central part of the basin. Above the coal beds, the Lulu Formation is dominated by various types of tidally influenced paralic deposits in the western part of the basin and by coarsening-upwards shoreface and beach deposits in central parts. Westwards-thickening wedges of paralic deposits interfinger with eastwards-thickening wedges of shallow marine deposits. The Middle Jurassic succession is subdivided into nine sequences. In the lower Bryne Formation, sequence boundaries are situated at the base of laterally continuous fluvial channel sandstones whereas maximum flooding surfaces are placed in laterally extensive floodplain

  1. Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany.

    Science.gov (United States)

    Gerke, Oliver; Wings, Oliver

    2016-01-01

    Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A-R) could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A) and Abelisauridae (morphotype K). This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q) differ only in some probably size-related characteristics from larger morphotypes (B and C) and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America.

  2. Relationship of voluminous ignimbrites to continental arc plutons: Petrology of Jurassic ignimbrites and contemporaneous plutons in southern California

    Science.gov (United States)

    Fohey-Breting, N. K.; Barth, A.P.; Wooden, J.L.; Mazdab, F.K.; Carter, C.A.; Schermer, E.R.

    2010-01-01

    Volcanism was broadly associated in both space and time with Mesozoic plutonism in the Cordillera continental margin arc, but the precise petrogenetic relationships between volcanic rocks and adjacent zoned plutons are not known. Igneous rocks in a tilted crustal section in California include four laterally extensive Jurassic ash flow tuffs from 550 to >1100 m thick underlain at deeper structural levels by Jurassic plutons. Zircon geochronology confirms previous correlations of individual tuffs, suggesting ignimbrites with eruptive volumes up to 800 km3 were deposited both during the apparent Early Jurassic plutonic lull as well as contemporaneous with solidification of regionally widespread Middle and Late Jurassic plutons. The tuffs are weakly to strongly porphyritic (5 to 55% phenocrysts) monotonous intermediate porphyritic dacite to low-silica rhyolite and show strong bulk rock chemical affinity to contemporaneous plutons. Trace element compositions of zircons from the tuffs and contemporaneous plutonic rocks record large and consistent differences in Hf/Zr and REE over similar ranges in Ti abundances, supporting bulk compositional similarities and illuminating similarities and variations in thermal histories despite the effects of hydrothermal alteration. ?? 2009 Elsevier B.V. All rights reserved.

  3. Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany

    Science.gov (United States)

    Gerke, Oliver; Wings, Oliver

    2016-01-01

    Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A—R) could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A) and Abelisauridae (morphotype K). This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q) differ only in some probably size-related characteristics from larger morphotypes (B and C) and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America. PMID:27383054

  4. Jurassic-Cretaceous Herpetofaunas from the Jehol Associated Strata in NE China:Evolutionary and Ecological Implications

    Institute of Scientific and Technical Information of China (English)

    WANG Yuan; DONG Liping; Susan E.EVANS

    2010-01-01

    @@ Jurassic-Cretaceous herpetofaunas have recently been recovered from tuffinterbedded lacustrine strata in northeastern(NE)China.Most of them are from the Early Cretaceous Jehol Group(131-120 Ma),which has yielded a diverse and important fossil assemblage including insects,plants,fishes and tetrapods.

  5. Tectonic interactions between India and Arabia since the Jurassic reconstructed from marine geophysics, ophiolite geology, and seismic tomography

    NARCIS (Netherlands)

    Gaina, Carmen; Van Hinsbergen, Douwe J J; Spakman, Wim

    2015-01-01

    Gondwana breakup since the Jurassic and the northward motion of India toward Eurasia were associated with formation of ocean basins and ophiolite obduction between and onto the Indian and Arabian margins. Here we reconcile marine geophysical data from preserved oceanic basins with the age and locati

  6. Basin architecture, salt tectonics, and Upper Jurassic structural styles, DeSoto Canyon Salt basin, northeastern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    MacRae, G.; Watkins, J.S. (Texas A M Univ., College Station, TX (United States))

    1993-10-01

    Despite the Gulf of Mexico being a mature hydrocarbon province, the least understood aspects of the basin's geologic history are undoubtedly those concerning pre-Middle Jurassic tectonic events and their implication for the tectonic and sedimentary evolution of the region. Despite awareness of the importance of continental extension during rifting, there are few quantitative studies that show the influence of crustal extension on basin architecture, the distribution of salt, and Late Jurassic sedimentation in the DeSoto Canyon Salt basin, northeastern Gulf of Mexico. Application of simplified isostatic principles using a lithospheric buoyancy model allow quantification of total tectonic subsidence, crustal thickness, crustal extension, and crust type. An average crustal thickness of 25 km and crustal extension [beta] values between 1.4 and 1.8 suggest the sedimentary succession is underlain by moderately stretched and attenuated continental crust. The widespread distribution and geometry of dipping subsalt reflectors, particularly in the shelfal areas, provide evidence for a Late Triassic-Early Jurassic phase of rifting prior to deposition of Middle Jurassic salt. Although deposition occurred in a slowly subsiding, stable marginal setting, salt movement and associated growth faulting are the most significant tectonic elements affecting the stratigraphic and structural development of the overlying strata.

  7. Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany.

    Directory of Open Access Journals (Sweden)

    Oliver Gerke

    Full Text Available Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A-R could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A and Abelisauridae (morphotype K. This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q differ only in some probably size-related characteristics from larger morphotypes (B and C and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America.

  8. Assessment of undiscovered oil and gas resources in Jurassic and Cretaceous strata of the Gulf Coast, 2010

    Science.gov (United States)

    Dubiel, Russell F.; Warwick, Peter D.; Swanson, Sharon; Burke, Lauri; Biewick, Laura R.H.; Charpentier, Ronald R.; Coleman, James L.; Cook, Troy A.; Dennen, Kris; Doolan, Colin; Enomoto, Catherine; Hackley, Paul C.; Karlsen, Alexander W.; Klett, Timothy R.; Kinney, Scott A.; Lewan, Michael D.; Merrill, Matt; Pearson, Krystal; Pearson, Ofori N.; Pitman, Janet K.; Pollastro, Richard M.; Rowan, Elizabeth L.; Schenk, Christopher J.; Valentine, Brett

    2011-01-01

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 147.4 trillion cubic feet of undiscovered natural gas, 2.4 billion barrels of undiscovered oil, and 2.96 billion barrels of undiscovered natural gas liquids in Jurassic and Cretaceous strata in onshore lands and State waters of the Gulf Coast.

  9. First Description of Genuine Shatter Cones in Upper Jurassic Limestone Clasts from the Bunte Breccia Impactites of the Ries Crater

    Science.gov (United States)

    Poesges, G. A.

    2016-08-01

    The Ries crater produced a wealth of lithologies that host shatter cones. This study reviews the occurrence of shatter cones in the Ries crater and reports the first finds of shatter cones in Upper Jurassic limestone clasts within the Bunte Breccia.

  10. A new early brachyuran (Crustacea, Decapoda) from the Middle Jurassic of northwest France, epibionts and ecological considerations

    NARCIS (Netherlands)

    Robin, N.; Bakel, van B.W.M.; Hondt, d' J.-L.; Charbonnier, S.

    2015-01-01

    The earliest known crabs are of Early and Middle Jurassic age; in general, they are rare. Here we describe a new species of homolodromioid from the late Bathonian of Sarthe (France), based on a single dorsal carapace, Tanidromites raboeufi n. sp. This specimen has mostly well-preserved cuticle, and

  11. Late Jurassic Crustal Thickening in the Mesozoic Arc of Ecuador and Colombia: Implications on the Evolution of Continental Arcs.

    Science.gov (United States)

    Vanegas, J.; Cardona, A.; Blanco-Quintero, I.; Valencia, V.

    2014-12-01

    The tectonic evolution of South America during the Jurassic is related to the subduction of the Farallon plate and the formation of a series of continental arcs. In the northern Andes such arcs have been considered as controlled by extensional dominated tectonics. Paleomagnetic constraints have also suggested that between the Early and Late Jurassic several crustal domains were translate along the continental margin in association with strain partitioning in the convergent margin. A review of the character of the Salado terrane in the Cordillera Real of Ecuador indicates that it includes extensively deformed and metamorphosed volcano-sedimentary rocks that have achieved a greenschist to amphibolite facies event with chloritoid and garnet. This rocks are tightly associated with a ca. 143 Ma syn-tectonic granodiorite to monzogranite batholith that is also extensively milonitized.A similar Late Jurassic crustal thickening event that apparently affected volcano-sedimentary rocks have been also recently suspected in the Central Cordillera of the Colombian Andes in association with Jurassic plutonic rocks (Blanco-Quintero et al., 2013) It is therefore suggested that during the Late Jurassic the Northern Andes experienced significant contractional tectonics. Such crustal thickening may be related to either the active subduction setting were the crustal slivers formed in relation to oblique convergence are transfered and re-accreted to the margin and triggered the deformational event or to a collisional event associated to the arrival of an allocthonous terrane. New geochronological constraints on the metamorphic evolution and precise understanding on the relations between magmatism and deformation are going to be obtain in the Salado Terrane to appropriately test this hypothesis and contribute to the understanding of the extensional to compressional tectonic switching in continental arcs. Blanco-Quintero, I. F., García-Casco, A., Ruíz, E. C., Toro, L. M., Moreno, M

  12. Middle Jurassic - Early Cretaceous rifting on the Chortis Block in Honduras: Implications for proto-Caribbean opening (Invited)

    Science.gov (United States)

    Rogers, R. D.; Emmet, P. A.

    2009-12-01

    Regional mapping integrated with facies analysis, age constraints and airborne geophysical data reveal WNW and NE trends of Middle Jurassic to Early Cretaceous basins which intersect in southeast Honduras that we interpret as the result of rifting associated with the breakup of the Americas and opening of the proto-Caribbean seaway. The WNW-trending rift is 250 km long by 90 km wide and defined by a basal 200 to 800 m thick sequence of Middle to Late Jurassic fluvial channel and overbank deposits overlain by transgressive clastic shelf strata. At least three sub-basins are apparent. Flanking the WNW trending rift basins are fault bounded exposures of the pre-Jurassic continental basement of the Chortis block which is the source of the conglomeratic channel facies that delineate the axes of the rifts. Cretaceous terrigenous strata mantle the exposed basement-cored rift flanks. Lower Cretaceous clastic strata and shallow marine limestone strata are dominant along this trend indicating that post-rift related subsidence continued through the Early Cretaceous. The rifts coincide with a regional high in the total magnetic intensity data. We interpret these trends to reflect NNE-WSW extension active from the Middle Jurassic through Early Cretaceous. These rifts were inverted during Late Cretaceous shortening oriented normal to the rift axes. To the east and at a 120 degree angle to the WNW trending rift is the 300 km long NE trending Guayape fault system that forms the western shoulder of the Late Jurassic Agua Fria rift basin filled by > 2 km thickness of clastic marine shelf and slope strata. This NE trending basin coincides with the eastern extent of the surface exposure of continental basement rocks and a northeast-trending fabric of the Jurassic (?) metasedimentary basement rocks. We have previously interpreted the eastern basin to be the Jurassic rifted margin of the Chortis block with the Guayape originating as a normal fault system. These two rifts basin intersect

  13. Emplacement of the Jurassic Mirdita ophiolites (southern Albania): evidence from associated clastic and carbonate sediments

    Science.gov (United States)

    Robertson, Alastair H. F.; Ionescu, Corina; Hoeck, Volker; Koller, Friedrich; Onuzi, Kujtim; Bucur, Ioan I.; Ghega, Dashamir

    2012-09-01

    Sedimentology can shed light on the emplacement of oceanic lithosphere (i.e. ophiolites) onto continental crust and post-emplacement settings. An example chosen here is the well-exposed Jurassic Mirdita ophiolite in southern Albania. Successions studied in five different ophiolitic massifs (Voskopoja, Luniku, Shpati, Rehove and Morava) document variable depositional processes and palaeoenvironments in the light of evidence from comparable settings elsewhere (e.g. N Albania; N Greece). Ophiolitic extrusive rocks (pillow basalts and lava breccias) locally retain an intact cover of oceanic radiolarian chert (in the Shpati massif). Elsewhere, ophiolite-derived clastics typically overlie basaltic extrusives or ultramafic rocks directly. The oldest dated sediments are calpionellid- and ammonite-bearing pelagic carbonates of latest (?) Jurassic-Berrasian age. Similar calpionellid limestones elsewhere (N Albania; N Greece) post-date the regional ophiolite emplacement. At one locality in S Albania (Voskopoja), calpionellid limestones are gradationally underlain by thick ophiolite-derived breccias (containing both ultramafic and mafic clasts) that were derived by mass wasting of subaqueous fault scarps during or soon after the latest stages of ophiolite emplacement. An intercalation of serpentinite-rich debris flows at this locality is indicative of mobilisation of hydrated oceanic ultramafic rocks. Some of the ophiolite-derived conglomerates (e.g. Shpati massif) include well-rounded serpentinite and basalt clasts suggestive of a high-energy, shallow-water origin. The Berriasian pelagic limestones (at Voskopoja) experienced reworking and slumping probably related to shallowing and a switch to neritic deposition. Mixed ophiolite-derived clastic and neritic carbonate sediments accumulated later, during the Early Cretaceous (mainly Barremian-Aptian) in variable deltaic, lagoonal and shallow-marine settings. These sediments were influenced by local tectonics or eustatic sea

  14. The Emergence of Pelagic Carbonate Production by Nannoplankton in The Early Jurassic

    Science.gov (United States)

    Mattioli, E.; Pittet, B.; Suan, G.; Sucheras-Marx, B.; Reggiani, L.; Planck, J.

    2008-12-01

    Coccolithophores are among the main carbonate producers in today's Oceans. They participate to the organic-carbon pump and carbonate counter-pump at the same time, and therefore have a fundamental role in the carbon cycle. In this regard, the first occurrence and subsequent diversification of calcareous nannoplankton and in particular of coccolithophorids (225-65 Mya) likely had a major impact on biogeochemical cycles and the regulation of pCO2 in the atmosphere/hydrosphere. Nevertheless, both causes and consequences of the emergence of calcareous nannoplankton between the Late Triassic and the Early Jurassic remain poorly understood. In order to address the possible relationships between the early diversification of coccolithopororids and the evolution of atmospheric CO2 conditions, we performed a quantitative micropaleontological study in the well-exposed sections outcropping along the west coast of Portugal, spanning the entire Lower Jurassic. The accumulation rates of pelagic carbonates were reconstructed using the absolute abundances and size estimates of the most important pelagic carbonate producers as well as the cyclostratigraphic calibration of the studied successions. Our results show that nannofossil absolute abundance, although fluctuating in the Early Jurassic, increased by discrete steps. The first step (up to 0.2 billion of nannofossils per gram of rock) occurred at the base of the Late Pliensbachian and coincided with the deposition of organic matter-rich sediments. A second, more important increase is recorded at the Pliensbachian/Toarcian transition (-183 Mya), when absolute abundance attained values of 1.1 billion of nannofossils per gram of rock. These abundances are comparable to the record of surface sediments deposited under oligotrophic conditions. The following decrease in coccolithophorids observed during the Early Toarcian oceanic anoxic event is particularly intriguing. The dramatic decrease or loss of biocalcification potential could

  15. A toothed turtle from the Late Jurassic of China and the global biogeographic history of turtles.

    Science.gov (United States)

    Joyce, Walter G; Rabi, Márton; Clark, James M; Xu, Xing

    2016-10-28

    Turtles (Testudinata) are a successful lineage of vertebrates with about 350 extant species that inhabit all major oceans and landmasses with tropical to temperate climates. The rich fossil record of turtles documents the adaptation of various sub-lineages to a broad range of habitat preferences, but a synthetic biogeographic model is still lacking for the group. We herein describe a new species of fossil turtle from the Late Jurassic of Xinjiang, China, Sichuanchelys palatodentata sp. nov., that is highly unusual by plesiomorphically exhibiting palatal teeth. Phylogenetic analysis places the Late Jurassic Sichuanchelys palatodentata in a clade with the Late Cretaceous Mongolochelys efremovi outside crown group Testudines thereby establishing the prolonged presence of a previously unrecognized clade of turtles in Asia, herein named Sichuanchelyidae. In contrast to previous hypotheses, M. efremovi and Kallokibotion bajazidi are not found within Meiolaniformes, a clade that is here reinterpreted as being restricted to Gondwana. A revision of the global distribution of fossil and recent turtle reveals that the three primary lineages of derived, aquatic turtles, including the crown, Paracryptodira, Pan-Pleurodira, and Pan-Cryptodira can be traced back to the Middle Jurassic of Euramerica, Gondwana, and Asia, respectively, which resulted from the primary break up of Pangaea at that time. The two primary lineages of Pleurodira, Pan-Pelomedusoides and Pan-Chelidae, can similarly be traced back to the Cretaceous of northern and southern Gondwana, respectively, which were separated from one another by a large desert zone during that time. The primary divergence of crown turtles was therefore driven by vicariance to the primary freshwater aquatic habitat of these lineages. The temporally persistent lineages of basal turtles, Helochelydridae, Meiolaniformes, Sichuanchelyidae, can similarly be traced back to the Late Mesozoic of Euramerica, southern Gondwana, and Asia. Given

  16. Jurassic hot spring deposits of the Deseado Massif (Patagonia, Argentina): Characteristics and controls on regional distribution

    Science.gov (United States)

    Guido, Diego M.; Campbell, Kathleen A.

    2011-06-01

    The Deseado Massif, Santa Cruz Province, Argentinean Patagonia, hosts numerous Middle to Late Jurassic age geothermal and epithermal features represented by siliceous and calcareous chemical precipitates from hot springs (sinters and travertines, respectively), hydrothermal breccias, quartz veins, and widespread hydrothermal silicification. They indicate pauses in explosive volcanic activity, marking the final stages in the evolution of an extensive Jurassic (ca. 178-151 Ma) volcanic complex set in a diffuse extensional back-arc setting heralding the opening of the Atlantic Ocean. Published paleo-hot spring sites for the Deseado Massif, plus additional sites identified during our recent field studies, reveal a total of 23 locations, five of which were studied in detail to determine their geologic and facies associations. They show structural, lithologic, textural and biotic similarities with Miocene to Recent hot spring systems from the Taupo and Coromandel volcanic zones, New Zealand, as well as with modern examples from Yellowstone National Park, U.S.A. These comparisons aid in the definition of facies assemblages for Deseado Massif deposits - proximal, middle apron and distal siliceous sinter and travertine terraces and mounds, with preservation of many types of stromatolitic fabrics - that likely were controlled by formation temperature, pH, hydrodynamics and fluid compositions. Locally the mapped hot spring deposits largely occur in association with reworked volcaniclastic lacustrine and/or fluvial sediments, silicic to intermediate lava domes, and hydrothermal mineralization, all of which are related to local and regional structural lineaments. Moreover, the numerous geothermal and significant epithermal (those with published minable resources) deposits of the Deseado Massif geological province mostly occur in four regional NNW and WNW hydrothermal-structural belts (Northwestern, Northern, Central, and Southern), defined here by alignment of five or more hot

  17. Petrogenesis and tectonic implications of Early Jurassic volcanic rocks of the Raohe accretionary complex, NE China

    Science.gov (United States)

    Wang, Zhi-Hui; Ge, Wen-Chun; Yang, Hao; Bi, Jun-Hui; Ji, Zheng; Dong, Yu; Xu, Wen-Liang

    2017-02-01

    The Raohe accretionary complex, located at the border between the Russian Far East and Northeastern China, is a significant part of the western Pacific Oceanic tectonic regime. Due to lack of precise age and geochemical constraints, the tectonic setting and petrogenesis of the magmatic rocks in this area remain undefined, resulting in debate about crustal growth mechanisms and subduction-related accretionary processes in Northeastern China. Here, we report whole-rock major and trace element and Sr-Nd isotope data, together with zircon U-Pb ages and in situ zircon Hf isotope data for calc-alkaline andesites, dacites, rhyolites, rhyolitic crystal tuffs, Nb-enriched andesites and basaltic andesites, and high-Mg andesites of the Raohe accretionary complex in NE China. Samples were collected from Late Triassic to Early Jurassic strata. However, geochronological results in this study indicated that the studied magmatism occurred in the Early Jurassic (187-174 Ma). The calc-alkaline volcanic rocks possess geochemical characteristics typical of arc magmas that form at active continental margins, such as moderate enrichments in large ion lithophile elements (LILEs) and light rare earth elements (LREEs), and depletions in high field strength elements (HFSEs). They have positive εHf(t) values of +3.4 to +10.6 and relatively high (87Sr/86Sr)i values of 0.7047-0.7102. While the Nb-enriched andesites and basaltic andesites have higher TiO2, Hf, Nb, and Zr contents and higher Nb/Ta (24.0-87.6), Nb/U (11.9-75.9), (Nb/Th)PM (0.67-2.70), and (Nb/La)PM (1.95-5.00) ratios than typical arc basalts. They have negative εNd(t) values (-5.5 to -6.0) and relatively variable (87Sr/86Sr)i values of 0.7047-0.7114, suggesting an origin via the partial melting of mantle wedge peridotite that had been metasomatized by slab-derived melt. The high-Mg volcanic rocks, characterized by high MgO and Mg#, TiO2, Al2O3, Cr, Ni, (La/Yb)N and (La/Sm)N, but low Ba/Th ratios, are geochemically similar to

  18. TECHNOLOGY VS NATURE: HUMAN ERROR IN DEALING WITH NATURE IN CRICHTON'S JURASSIC PARK

    Directory of Open Access Journals (Sweden)

    Sarah Prasasti

    2000-01-01

    Full Text Available Witnessing the euphoria of the era of biotechnology in the late twentieth century, Crichton exposes the theme of biotechnology in his works. In Jurassic Park, he voices his concern about the impact of the use of biotechnology to preserve nature and its living creatures. He further describes how the purpose of preserving nature and the creatures has turned out to be destructive. This article discusses Crichton's main character, Hammond, who attempts to control nature by genetically recreating the extinct fossil animals. It seems that the attempt ignores his human limitations. Although he is confident that has been equipped with the technology, he forgets to get along with nature. His way of using technology to accomplish his purpose proves not to be in harmony with nature. As a consequence, nature fights back. And he is conquered.

  19. A new sauropod dinosaur from the Middle Jurassic of the United Kingdom.

    Science.gov (United States)

    Manning, Phillip L; Egerton, Victoria M; Romano, Mike

    2015-01-01

    A new record of a sauropodomorph dinosaur is here described from the Middle Jurassic (Aalenian) Saltwick Formation of Whitby (Yorkshire), UK. A single caudal vertebra represents an early sauropodomorph and signifies the earliest recognised eusauropod dinosaur from the United Kingdom. The absence of pleurocoels and a narrow, dorsoventrally deep, but craniocaudally short centrum, suggests a primitive sauropodomorph. Distinct spinopostzygopophyseal laminae rise from the lateral margins of the postzygapophyses and pass caudally along what remains of the neural spine, a character unique to a subgroup of sauropods that includes Barapasaurus, Omeisaurus and other neosauropods and eusauropods. The lack of phylogenetically robust characters in sauropod caudal vertebrae usually makes it difficult to establish affinities, but the absence of mild procoely excludes this specimen from both Diplodocoidea and Lithostrotia. The vertebra cannot be further distinguished from those of a wide range of basal sauropods, cetiosaurids and basal macronarians. However, this plesiomorphic vertebra still signifies the earliest stratigraphic occurrence for a British sauropod dinosaur.

  20. Ascent of dinosaurs linked to an iridium anomaly at the Triassic-Jurassic boundary.

    Science.gov (United States)

    Olsen, P E; Kent, D V; Sues, H-D; Koeberl, C; Huber, H; Montanari, A; Rainforth, E C; Fowell, S J; Szajna, M J; Hartline, B W

    2002-05-17

    Analysis of tetrapod footprints and skeletal material from more than 70 localities in eastern North America shows that large theropod dinosaurs appeared less than 10,000 years after the Triassic-Jurassic boundary and less than 30,000 years after the last Triassic taxa, synchronous with a terrestrial mass extinction. This extraordinary turnover is associated with an iridium anomaly (up to 285 parts per trillion, with an average maximum of 141 parts per trillion) and a fern spore spike, suggesting that a bolide impact was the cause. Eastern North American dinosaurian diversity reached a stable maximum less than 100,000 years after the boundary, marking the establishment of dinosaur-dominated communities that prevailed for the next 135 million years.

  1. A new sauropod dinosaur from the Middle Jurassic of the United Kingdom.

    Directory of Open Access Journals (Sweden)

    Phillip L Manning

    Full Text Available A new record of a sauropodomorph dinosaur is here described from the Middle Jurassic (Aalenian Saltwick Formation of Whitby (Yorkshire, UK. A single caudal vertebra represents an early sauropodomorph and signifies the earliest recognised eusauropod dinosaur from the United Kingdom. The absence of pleurocoels and a narrow, dorsoventrally deep, but craniocaudally short centrum, suggests a primitive sauropodomorph. Distinct spinopostzygopophyseal laminae rise from the lateral margins of the postzygapophyses and pass caudally along what remains of the neural spine, a character unique to a subgroup of sauropods that includes Barapasaurus, Omeisaurus and other neosauropods and eusauropods. The lack of phylogenetically robust characters in sauropod caudal vertebrae usually makes it difficult to establish affinities, but the absence of mild procoely excludes this specimen from both Diplodocoidea and Lithostrotia. The vertebra cannot be further distinguished from those of a wide range of basal sauropods, cetiosaurids and basal macronarians. However, this plesiomorphic vertebra still signifies the earliest stratigraphic occurrence for a British sauropod dinosaur.

  2. A New Mamenchisaurid Dinosaur from the Middle Jurassic of Yuanmou, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    L(U) Junchang; LI Tianguang; ZHONG Shimin; JI Qiang; LI Shaoxue

    2008-01-01

    A new mamenchisaurid dinosaur, Eomamenchisaurus yuanmouensis gen et sp. nov. Is erected based on an incomplete skeleton from the Zhanghe Formation, the Middle Jurassic of Yuanmou, Yunnan Province. The new taxon is characterized by absence of pleurocoels in dorsal vertebrae and the dorsal verterbrae with slightly convex anterior articular surfaces, moderately concave posterior articular surfaces; the fourth trochanter is developed posteromedially on the femur; length ratio of the tibia to the femur is approximately 0.64; and the shaft of the ischium is rod-like. Two fused centra of the posterior dorsal vertebrae (the presumed 9th and the 10th dorsal vertebrae) are similar to those in other mamenchisaurid dinosaurs, including Mamenchisaurus hochuanesis, M. youngi and Chuanjiesaurus anaensis. Therefore, fusion of centra of the ninth and the tenth dorsal vertebrae can be recognized as a synapomorphic character of the Mamenchisauridae.

  3. Petrographic and geochemical characterization of the Triassic and Jurassic magmatic and volcanic rocks of southeastern Ecuador

    Science.gov (United States)

    Villares, Fabián; Eguez, Arturo; Yanez, Ernesto

    2014-05-01

    Formely, the subandean zone in the southeastern Ecuador involved large volcanic and magmatic rocks included in the Misahualli Formation and Zamora batholith, both as expression of the Jurassic cal-alcaline volcanic arc. The aim of the project carried out by the INIGEMM (Instituto Nacional de Investigación Geológico Minero Metalúrgico) was discriminate the volcanic products including a continuous set going from basalts to ryolithes and volcanoclastic rocks. Geochemical characterization was done using representative 16 whole - rock chemical analysis. The oldest rocks of the investigated area called Pachicutza Unit, include greenish to black, massive basalts and basaltic andesites, locally showing pillows structures. The texture is aphanitic to microporphyritic with slight crystal growth of plagioclase and pyroxenes. The Unit include also local pyroclastic breccias and tuffs showing variable skarnification related to the intrusion of the jurassic Zamora Batholith. Two samples of basalts show tholeiitic affinity, corresponding to an N- MORB, probably representing an early stage in opening of a regional Triassic rift reported since Colombia to Peru in the Andes. These geochemical characteristics are similar to the amphibolites of Monte Olivo Unit in the Real Cordillera. The Jurassic large volcanic assembly of the Misahualli Formation was also differenciated. Basal volcanics include green, subporphyritic andesites and volcanic breccias possibly generated at an early stage of the volcanic arc, caused by a change of extensive to compressive regime. Continental volcano sedimentary and sedimentary rock were discriminate as Nueva Esperanza and Suarez Units, respectively. The volcanosedimentary sequence include massive to laminate tuffs and tuffites of intermediate composition. The sediments of the Suarez Unit include dominant conglomerats and sandstones of fluvial domain. The regional volcanic sequence is completed by the Las Peñas Unit that includes aphanitic to

  4. Upper Triassic and Lower Jurassic beds in the Podutik area near Ljubljana (Slovenia

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    Matevž Novak

    2003-06-01

    Full Text Available In the Podutik area near Ljubljana in a very shallow lagoon environment of the restricted shelf on the Dinaric carbonate platform the Main dolomite formation originated in Norian and Rhaetian. In the northern part of the carbonate platform on the opened shelfarea the Dachstein limestone has been deposited. In the studied area both above-mentioned lithologic units occur in the typical Lofer development. Due to lack of fossils the Rhaetian stage is not separated from the Norian one. The boundary between the Triassicand the Jurassic period is marked chiefly by the gradual lithologic transition. It is focused into the zone, where the Lofer limestone with large megalodontids passes into the limestone with characteristically dark red calcite veinlets, intercalations of oolitic and onkolitic limestone and algae Palaeodasycladus mediterraneus Pia.

  5. Biological liquefaction characteristics of Jurassic weak & non-stick coal in Hengshan, North Shaanxi Province

    Institute of Scientific and Technical Information of China (English)

    DU Mei-li; CHEN Hong-gui; JIANG Su-rong

    2008-01-01

    Jurassic weak & non-stick coal in Hengshan of North Shaanxi Province waspretreated by the nitric acid. Then, it was biodegraded by Phanerochaete chrysosporium.The biodegradation role of the white-rot fungus for coal is extremely significant. Orthogo-nal test demonstrate that liquefied time, liquefaction temperature and the amount of fun-gus liquids etc. are the main factors affecting the coal biodegradation rate. The best tech-nical condition of the coal biological liquefaction was got. Comparing the coal sample be-fore biodegradation with that after biodegradation, it is found that the ash of the coal resi-due after biodegradation reduces significantly, H and O contents increase, C and N con-tents decrease. The biodegradation change the coal macromolecular structure.

  6. The first fossil wedge-shaped beetle (Coleoptera, Ripiphoridae from the middle Jurassic of China

    Directory of Open Access Journals (Sweden)

    Yun Hsiao

    2017-02-01

    Full Text Available A new species of Ripiphoridae Gemminger & Harold, 1870, Archaeoripiphorus nuwa gen. et sp. nov., is described and illustrated from a well-preserved impression fossil from the Middle Jurassic Jiulongshan Formation collected at Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China, representing the oldest documented occurrence of the Ripiphoridae described from the Mesozoic era. It shares several characters belonging to two basal ripiphorid subfamilies (Pelecotominae and Ptilophorinae, but it cannot be attributed to either of them and is herein placed as Subfamily incertae sedis. An overall similarity between Archaeoripiphorus gen. nov. and Recent Pelecotominae and the occurrence of wood-boring beetles in the same Formation implies a similar parasitoid host preference in xylophagous beetles for A. nuwa gen. et sp. nov., putting a spotlight on a potential host-parasitoid relationship in the Mesozoic.

  7. Some of Alpheus Hyatt's unfigured types from the Jurassic of California

    Science.gov (United States)

    Crickmay, C.H.

    1933-01-01

    Alpheus Hyatt named a considerable number of Jurassic fossils from California. Only a few of these were described, arid none were illustrated. In this paper 16 of these species are evaluated in terms of present-day nomenclature, figures of the type specimens are shown, and their probable age significance is given. Included are Monotis semiplicata (=Entolium semiplicata),Monotis symmetrica (=Entolium symmetrica), Daonella?subjecta ( = '' Daonella" subjecta), Daonella bOchiformts (=" Daonella" bOchiformis), Daonella cardinoides (="Duonella"cardinoides), A ucella erringtoni var. arcuata ( = Buchia arcuata), Aucella elongata ( = Buchia elongata), AuceUa var.elongata orbicularis ( = Buchia sinzovi), Aucella aviculaeformis ( = Buchia erringtoni var. aviculaeformis), Aucella aviculaeformis var. acuta ( = Buchia erringtoni var. orbicularis), Aucella orb·.icularis( = Buchia erringtoni var. orbicularis), Cardioceras dub\\~um ( = Amoeboceras dubium), Perisphinctes virgulatiformis ( = Viigatosphinctes virgulatiformis), Perisphinctes miihlbachi ( = Dichotomoceras miihlbachi), iJlcostephanus lindgreni ( =" Galilaeiceras"

  8. The geology and hydrocarbon possibilities of the Triassic-Jurassic Fundy Basin, eastern Canada

    Energy Technology Data Exchange (ETDEWEB)

    Wade, J.A.; Fensome, R.A. [Geological Survey of Canada, Dartmouth, NS (Canada). Atlantic Geoscience Centre; Brown, D.E. [Canada-Nova Scotia Offshore Petroleum Board, Halifax, NS (Canada)

    1997-09-01

    The development of the Mesozoic sedimentary basins beneath the waters of the eastern coast of North America was discussed. These basins have been linked to the rifting of the central part of Pangaea during Mid and Late Triassic time that ended in the formation of a series of grabens extending from Florida to The Grand Banks of Newfoundland, one of them being the Bay of Fundy Basin which is about 16,500 square kilometres in size. Onshore and offshore geologic mapping and seismic interpretations have shown their age range to be from the Mid Triassic Anisian or Ladinian to Mid Jurassic. Up to 12 km of Mesozoic rocks were deposited in the basin with up to 9 km still present. The depositional history of the area was described. The two areas with greatest hydrocarbon potential are the Bay of Fundy and the Chignecto subbasins.

  9. A New Family of Moths from the Middle Jurassic(Insecta:Lepidoptera)

    Institute of Scientific and Technical Information of China (English)

    HUANG Diying; André NEL; Jo(e)l MINET

    2010-01-01

    Three lepidopteran species,from the Middle Jurassic Daohugou beds(inner Mongolia,China),are described in a new family,Mesokristeuseniidae,and new genus,Mesokristensenia,which could represent the sister group of the Micropterigidae.Mesokristensenia differs from all extant Lepidoptera,but one genus(Agathiphaga,Agathiphagidae),in retaining four median veins in the forewing,a plesiomorphy also present in many Trichoptera.Evidence for placing Mesokristensenia in the Lepidoptera includes four traits,notably a previously unrecorded autapomorphy of this insect order:beyond stem M1+2,vein M1 is bent and connected to cross-vein r-m(in both wing pairs).Among 24 characters taken into account to assess the systematic position of Mesokristensenia,12 are considered informative for a cladistic analysis involving this fossil taxon and the four suborders recognized in present-day Lepidoptera(Zeugloptera,Aglossata,Heterobathmiina,and Glossata).

  10. Macromycetes of oak forests in the Jurassic Landscape Park (Częstochowa Upland - monitoring studies

    Directory of Open Access Journals (Sweden)

    Maria Ławrynowicz

    2014-08-01

    Full Text Available Mycological observations were carried out between 1994-1996 in two representative plots (1000 m2 each in 80-year-old oak plantation (Quercus robur and Qu. petraea on calcareous hill in the Mstów village in the Jurassic Landscape Park. The project was carried out in the frame of international network of the „Mycological monitoring in European oak forests". During 24 visits in the plots a total of 190 species of macromycetes was recorded: 80 mycorrhizal and 110 saprobic fungi. Among them 2 species are new to Poland and 16 are inscribed in the Red List of threatened macromycetes in Poland (Wojewoda and Ławrynowicz 1992.

  11. The vertebrate fauna from the stipite layers of the Grands Causses (Middle Jurassic, France

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    Fabien eKnoll

    2014-09-01

    Full Text Available The stipites are Bathonian (Middle Jurassic coals that formed in an everglades-like environment and are now exposed in the Grands Causses (southern France. The vertebrate assemblage of the stipites and of the transitional layers to the carbonates in which they are interspersed are reviewed. To date, only small-sized and isolated vertebrate bones, teeth, and scales have been recovered. These record the presence of sharks (Hybodus, Asteracanthus, bony fishes (Lepidotes, Pycnodontiformes, Caturus, Aspidorhynchus, amphibians (Anura, Albanerpetontidae, and reptiles (Crocodylomorpha, Ornithischia, Theropoda. Despite its relatively limited taxonomic diversity, the vertebrate assemblage from the stipites and from their associated layers is notable for being one of the few of this age with both terrestrial and marine influences. Compared to other approximately coeval formations in Western Europe, the stipites vertebrate assemblage is surpassed in diversity only by those from the British Isles.

  12. New discovery of Palaeontinid fossils from the Middle Jurassic in Daohugou, Inner Mongolia (Homoptera, Palaeontinidae)

    Institute of Scientific and Technical Information of China (English)

    SHIH; ChungKun

    2007-01-01

    Three new species of fossil Palaeontinidae are described from Daohugou Village, Inner Mongolia, China: Daohugoucossus shii sp. nov., D. parallelivenius sp. nov., D. lii sp. nov. The diagnosis of Dao- hugoucossus Wang, Zhang and Fang, 2006 is revised. These materials are the first complete fossil palaeontinids in the Middle Jurassic of the world. Based on observation of these new specimens, Sc of this new genus has the following combined characters: joined with R at base, diverged near M separa- tion, coalesced with R before the nodal line, extended beyond the nodal line and fused with R1 before distal end. Due to the Sc characteristics mentioned above, the genus Liaocossus Ren, Yin and Dou, 1998 can be well distinguished from “Ilerdocossus-complex”.

  13. A Jurassic stem pleurodire sheds light on the functional origin of neck retraction in turtles

    Science.gov (United States)

    Anquetin, Jérémy; Tong, Haiyan; Claude, Julien

    2017-01-01

    Modern turtles are composed of two monophyletic groups, notably diagnosed by divergent neck retraction mechanisms. Pleurodires (side-necked turtles) bend their neck sideways and protect their head under the anterior margin of the carapace. Cryptodires (hidden-necked turtles) withdraw their neck and head in the vertical plane between the shoulder girdles. These two mechanisms of neck retraction appeared independently in the two lineages and are usually assumed to have evolved for protective reasons. Here we describe the neck of Platychelys oberndorferi, a Late Jurassic early stem pleurodire, and find remarkable convergent morphological and functional similarities with modern cryptodires. Partial vertical neck retraction in this taxon is interpreted to have enabled fast forward projection of the head during underwater prey capture and offers a likely explanation to the functional origin of neck retraction in modern cryptodires. Complete head withdrawal for protection may therefore have resulted from an exaptation in that group. PMID:28206991

  14. The Jurassic of East Greenland: a sedimentary record of thermal subsidence, onset and culmination of rifting

    Energy Technology Data Exchange (ETDEWEB)

    Surlyk, F. [Univ. of Copenhagen, Copenhagen (Denmark)]. Geological Inst.

    2003-07-01

    The Late Palaeozoic - Mesozoic extensional basin complex of East Greenland contains a record of deposition during a period of Rhaetian - Early Bajocian thermal subsidence, the onset of rifting in the Late Bajocian, its growth during the Bathonian-Kimmeridgian, culmination of rifting in the Volgian - Early Ryazanian, and waning in the Late Ryazanian - Hauterivian.,The area was centred over a palaeolatitude of about 45 deg C N in the Rhaetian and drifted northwards to about 50 deg C N in the Hauterivian. A major climate change from arid to humid subtropical conditions took place at the Norian-Rhaetian transition. Deposition was in addition governed by a long-term sea-level rise with highstands in the Toarcian-Aalenian, latest Callovian and Kimmeridgian, and lowstands in the latest Bajocian - earliest Bathonian, Middle Oxfordian and Volgian. The Rhaetian - Lower Bajocian succession is considered the upper part of a megasequence, termed Jl, with its base in the upper Lower Triassic, whereas the Upper Bajocian - Hauterivian succession forms a complete, syn-rift megasequence, termed J2. The southem part of the basin complex in Jameson Land contains a relatively complete Rhaetian-Ryazanian succession and underwent only minor tilting during Middle Jurassic - earliest Cretaceous rifting. Rhaetian - Lower Jurassic deposits are absent north of Jameson Land and this region was fragmented into strongly tilted fault blocks during the protracted rift event. The syn-rift successions of the two areas accordingly show different long-term trends in sedimentary facies. In the southern area, the J2 syn-rift megasequence forms a symmetrical regressive-transgressive-regressive cycle, whereas the J2 megasequence in the northem area shows an asymmetrical, stepwise deepening trend. A total of eight tectonostratigraphic sequences are recognised in the Rhaetian-Hauterivian interval. They reflect major changes in basin configuration, drainage systems, sediment transport and distribution

  15. Middle Jurassic spinicaudatan Shizhuestheria from the Sichuan Basin and its ontogenetic implication

    Institute of Scientific and Technical Information of China (English)

    HIRANO; Hiromichi; KOZAI; Takeshi; SAKAI; Takashi

    2009-01-01

    The diagnosis of the Middle Jurassic spinicaudatan genus Shizhuestheria is revised following the re-examination under a scanning electron microscope of a type specimen from Yanxi of Shizhu, and the newly collected specimens from Xintiangou of Chengjiang Town, Beibei, Chongqing. Small-sized reticulations occur not only in the middle-sized reticulations on growth bands on the dorsal side of the carapace, but also on growth bands on the ventral side of the carapace, which have been overlooked in the original description. The shift from wide dorsal growth bands to narrow ventral ones might indicate an onset of sexual maturity, and the transition in biological priorities from rapid juvenile growth to reproductive activities.

  16. Sense-making—A case study using the movie Jurassic park

    Science.gov (United States)

    Murphy, Tony P.

    1996-03-01

    In this ecological age, communicating information on environmental issues is extremely important. Yet, problems exist in communication models where knowledge is seen as absolute and the individual envisioned as an empty receptacle. What happens when a person assimilates knowledge? How does this knowledge relate to a person's view of the world (reality)? This paper is a brief introduction to Sense-Making, an alternative methodology which allows an insight into a person's perception of reality. Interviews were conducted with science teachers following a viewing of Jurassic Park to investigate the relationship of the movie to their ontological view of science, society and self. The Sense-Making methodology may be very beneficial in helping educators and communicators to understand the assimilation of knowledge by people and consequently the development of future communication models on scientific and environmental issues.

  17. A new primitive Neornithischian dinosaur from the Jurassic of Patagonia with gut contents

    Science.gov (United States)

    Salgado, Leonardo; Canudo, José I.; Garrido, Alberto C.; Moreno-Azanza, Miguel; Martínez, Leandro C. A.; Coria, Rodolfo A.; Gasca, José M.

    2017-02-01

    We describe a new species of an ornithischian dinosaur, Isaberrysaura mollensis gen. et sp. nov. The specimen, consisting in an almost complete skull and incomplete postcranium was collected from the marine-deltaic deposits of the Los Molles Formation (Toarcian-Bajocian), being the first reported dinosaur for this unit, one of the oldest from Neuquén Basin, and the first neornithischian dinosaur known from the Jurassic of South America. Despite showing a general stegosaurian appearance, the extensive phylogenetic analysis carried out depicts Isaberrysaura mollensis gen. et sp. nov. as a basal ornithopod, suggesting that both Thyreophora and neornithischians could have achieved significant convergent features. The specimen was preserved articulated and with some of its gut content place in the middle-posterior part of the thoracic cavity. Such stomach content was identified as seeds, most of them belonging to the Cycadales group. This finding reveals a possible and unexpected role of this ornithischian species as seed-dispersal agent.

  18. A possible tsunami deposit around the Jurassic Cretaceous boundary in the Boulonnais area (northern France)

    Science.gov (United States)

    Schnyder, Johann; Baudin, François; Deconinck, Jean-François

    2005-06-01

    An unusual succession of facies locally deposited around the Jurassic-Cretaceous boundary in the Boulonnais (northern France) is attributed to a tsunami event by comparison with recent tsunami deposits. This sedimentary succession includes basal erosion with reworked lithified blocks, soft-sediment deformations, an erosional conglomerate overlain by wood fragments and clays containing continental and marine fossils in one setting and conglomerate with mixed fauna in an other setting. The tsunami probably affected the coast of the Boulonnais area of the London-Brabant Massif. The origin of the event is unknown. It was most probably triggered by an earthquake, but other origins such as volcanic eruptions, a giant landslide, or even the impact of an extraterrestrial bolide into the ocean may also be considered.

  19. Body size and body volume distribution in two sauropods from the Upper Jurassic of Tendaguru (Tanzania

    Directory of Open Access Journals (Sweden)

    H.-C. Gunga

    1999-01-01

    Full Text Available Allometric equations are often based on the body mass of an animal because body mass determines many physiological functions. This should also hold for Brachiosaurus brancai and Dicraeosaurus hansemanni, two sauropods from the Upper Jurassic of Tendaguru/Tanzania (East Africa. Widely divergent estimates of body mass for the same specimen can be found in the literature for these two sauropods. Therefore, in order to determine the exact body mass and volume distribution in these sauropods, classical three-dimensional stereophotogrammetry as well as a newly developed laser scanner technique were applied to the mounted skeletons of Brachiosaurus brancai and Dicraeosaurus hansemanni in the Museum für Naturkunde (Berlin, Germany. Thereafter, scaling equations were used to estimate the size of organ systems. In a second step it was tested whether the given data from photogrammetry could be brought in line with the results derived from the allometric equations. These findings are applied to possible ecological problems in the Upper Jurassic of Tendaguru/Tanzania. Der Körpermasse eines Organismus werden oft allometrische Funktionen zugrunde gelegt, da von ihr viele physiologische Funktionen entscheidend abhängen. Dies sollte auch für ausgestorbene Organismen wie Brachiosaurus brancai und Dicraeosaurus hansemanni, zwei Sauropoden aus dem oberen Jura von Tendaguru/Tanzania in Ostafrika gelten. Da zu beiden Sauropoden nur sehr unterschiedliche Massenabschätzungen vorliegen, wurden die Körpermassen und Volumina von Brachiosaurus brancai und Dicraeosaurus hansemanni mit Hilfe der klassischen Photogrammetrie sowie einem neuentwickelten Laserscannerverfahren neu bestimmt. Basierend auf den so gemessenen Körpermassendaten wurden anschließend einige wichtige funktionell-morphologische Größen für eine paläophysiologische Rekonstruktion dieser Sauropoden mit Hilfe der Allometrie berechnet. Die gewonnenen Ergebnisse sind u. a. wichtig für die

  20. The cranial osteology of Tyrannoneustes lythrodectikos (Crocodylomorpha: Metriorhynchidae) from the Middle Jurassic of Europe.

    Science.gov (United States)

    Foffa, Davide; Young, Mark T

    2014-01-01

    Tyrannoneustes lythrodectikos is one of numerous metriorhynchid crocodylomorph species known from the Oxford Clay Formation of England (Callovian-Oxfordian; Middle-Late Jurassic). This taxon is of evolutionary importance, as it is the oldest and most basal known macrophagous metriorhynchid. It has a mosaic of plesiomorphic and derived feeding related characteristics, including: teeth with microscopic, poorly formed and non-contiguous denticles; increased tooth apicobasal length; ventrally displaced dentary tooth row (increased gape); reduced dentary tooth count; and a proportionally long mandibular symphysis. However the type specimen, and current referred specimens, all lack a preserved cranium. As such, the craniofacial morphology of this taxon, and its potential feeding ecology, remains poorly understood. Here we describe two skulls and two lower jaws which we refer to T. lythrodectikos. Previously these specimens were referred to 'Metriorhynchus' brachyrhynchus. They share with the T. lythrodectikos holotype: the in-line reception pits on the dentary, dorsal margin of the surangular is strongly concave in lateral view, and the most of the angular ventral margin is strongly convex. Based on our description of these specimens, the skull of T. lythrodectikos has three autapomorphies: very long posterior processes of the premaxilla terminating in line with the 4th or 5th maxillary alveoli, deep lateral notches on the lateral surface of the maxillary with reception pits for dentary teeth, and the premaxilla forms the anterior margin of the first maxillary alveoli. Our description of the cranial anatomy of Tyrannoneustes lythrodectikos confirms that some macrophagous characteristics evolved during the Middle Jurassic, and were not exclusive to the clade Geosaurini. Moreover, the skulls further highlight the mosaic nature of Tyrannoneustes lythrodectikos and wide-gape macrophagous evolution in Geosaurinae.

  1. Synchronous wildfire activity rise and mire deforestation at the triassic-jurassic boundary.

    Directory of Open Access Journals (Sweden)

    Henrik I Petersen

    Full Text Available The end-Triassic mass extinction event (∼201.4 million years ago caused major faunal and floral turnovers in both the marine and terrestrial realms. The biotic changes have been attributed to extreme greenhouse warming across the Triassic-Jurassic (T-J boundary caused by massive release of carbon dioxide and/or methane related to extensive volcanism in the Central Atlantic Magmatic Province (CAMP, resulting in a more humid climate with increased storminess and lightning activity. Lightning strikes are considered the primary source of wildfires, producing charcoal, microscopically recognized as inertinite macerals. The presence of polycyclic aromatic hydrocarbons (PAHs of pyrolytic origin and allochthonous charcoal in siliciclastic T-J boundary strata has suggested widespread wildfire activity at the time. We have investigated largely autochthonous coal and coaly beds across the T-J boundary in Sweden and Denmark. These beds consist of predominantly organic material from the in situ vegetation in the mires, and as the coaly beds represent a substantial period of time they are excellent environmental archives. We document a remarkable increase in inertinite content in the coal and coaly beds across the T-J boundary. We show estimated burning temperatures derived from inertinite reflectance measurements coupled with palynological data and conclude that pre-boundary late Rhaetian mire wildfires included high-temperature crown fires, whereas latest Rhaetian-Sinemurian mire wildfires were more frequent but dominated by lower temperature surface fires. Our results suggest a major change in the mire ecosystems across the T-J boundary from forested, conifer dominated mires to mires with a predominantly herbaceous and shrubby vegetation. Contrary to the overall regional vegetation for which onset of recovery commenced in the early Hettangian, the sensitive mire ecosystem remained affected during the Hettangian and did not start to recover until around

  2. UPPER JURASSIC OUTCROPS ALONG THE CALDAS DA RAINHA DIAPIR, WEST CENTRAL PORTUGAL: A REGIONAL GEOHERITAGE OVERVIEW

    Directory of Open Access Journals (Sweden)

    JORGE DINIS

    2004-03-01

    Full Text Available The Mesozoic Portuguese geological heritage is very rich and varied, a legacy of the position in the western margin of Iberia and its relationship with the evolution of the North Atlantic, with an interesting tectonic history since the Late Triassic. Regarding the Upper Jurassic several connections can be established between the tectonics and the stratigraphic record in the area surrounding the Caldas da Rainha structure: the basement and salt pillow control on deposition; the beginning of a diapiric and magmatic cycle associated to the on-set of sea-floor and the exhumation of both Jurassic deposits and the core of their controlling diapirs. The nature of the outcrops and richness in sedimentary environments, related with the different phases of rifting, is a remarkable case for extensional basin studies. Geological sites can be of regional, national or international importance due to scientific, educational, economical, social or historical reasons. The present proposal can be considered as a model for the establishment of tourist/educational routes with a strong component in communication on Earth Sciences, integrating social and historical aspects at a regional level. The recognition of those sites as geoheritage may contribute to a more sustainable management, in particular because it allows the achievement of a critical dimension for the investment in human resources and marketing. In Portugal, recent legal evolution might be considered promising. Nevertheless, since implementation of the concept of protected site depends on the approval of detailed management programs, there are frequent delays, misinterpretations and disrespect of legislation. The strategy to be adopted must integrate conservation, scientific studies and science communication in projects with economic and social interest.

  3. Equatorial origin for Lower Jurassic radiolarian chert in the Franciscan Complex, San Rafael Mountains, southern California

    Science.gov (United States)

    Hagstrum, J.T.; Murchey, B.L.; Bogar, R.S.

    1996-01-01

    Lower Jurassic radiolarian chert sampled at two localities in the San Rafael Mountains of southern California (???20 km north of Santa Barbara) contains four components of remanent magnetization. Components A, B???, and B are inferred to represent uplift, Miocene volcanism, and subduction/accretion overprint magnetizations, respectively. The fourth component (C), isolated between 580?? and 680??C, shows a magnetic polarity stratigraphy and is interpreted as a primary magnetization acquired by the chert during, or soon after, deposition. Both sequences are late Pliensbachian to middle Toarcian in age, and an average paleolatitude calculated from all tilt-corrected C components is 1?? ?? 3?? north or south. This result is consistent with deposition of the cherts beneath the equatorial zone of high biologic productivity and is similar to initial paleolatitudes determined for chert blocks in northern California and Mexico. This result supports our model in which deep-water Franciscan-type cherts were deposited on the Farallon plate as it moved eastward beneath the equatorial productivity high, were accreted to the continental margin at low paleolatitudes, and were subsequently distributed northward by strike-slip faulting associated with movements of the Kula, Farallon, and Pacific plates. Upper Cretaceous turbidites of the Cachuma Formation were sampled at Agua Caliente Canyon to determine a constraining paleolatitude for accretion of the Jurassic chert sequences. These apparently unaltered rocks, however, were found to be completely overprinted by the A component of magnetization. Similar in situ directions and demagnetization behaviors observed in samples of other Upper Cretaceous turbidite sequences in southern and Baja California imply that these rocks might also give unreliable results.

  4. CALCAREOUS NANNOFOSSILS AT THE TRIASSIC/JURASSIC BOUNDARY: STRATIGRAPHIC AND PALEOCEANOGRAPHIC CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    CINZIA BOTTINI

    2016-10-01

    Full Text Available In this work, calcareous nannofossils are identified for the first time in the uppermost Triassic sequence of the Lombardy Basin (Southern Calcareous Alps, Italy. Two zones are recognized, namely the NT2b (latest Triassic and the NJT1 (earliest Jurassic. Two species resulted to be good markers to constrain the TJB interval: Prinsiosphaera triassica and Schizosphaerella punctulata. Nannofossil data are calibrated with C isotopic chemostratigraphy obtained for carbonate and organic matter. Size reduction of P. triassica and a decline in the abundance of Triassic nannofossils are detected soon after the “precursor Carbon Isotope Excursion (CIE and culminated during the “initial negative CIE” characterized by lowest nannofossil abundances and small-sized P. triassica. The extinction of Triassic nannofossils occurred in distinctive steps within the “initial negative CIE”, while the Jurassic S. punctulata is first observed at the base of the “main negative CIE”. The latest Triassic nannofossil decline in abundance, size reduction and extinctions, represent a progressive deterioration associated to the Central Atlantic Magmatic Province (CAMP volcanism. Our findings are consistent with nannofossil changes at supraregional scale and indicate that the massive CAMP flood basalts were preceded by initial volcanic pulses. We speculate that a combination of climate change, fertilization and ocean acidification started to influence the calcification process prior to the “initial negative CIE”. Nannoplankton extinctions were not simultaneous and might imply limited capacity for adaptation in the early stages of evolutionary history. However, originations of new taxa soon after the disappearance of Triassic forms suggest the ability to rapidly overcame extreme stressing conditions.

  5. Sequence stratigraphy of the Kingak Shale (Jurassic-Lower Cretaceous), National Petroleum Reserve in Alaska

    Science.gov (United States)

    Houseknecht, D.W.; Bird, K.J.

    2004-01-01

    Beaufortian strata (Jurassic-Lower Cretaceous) in the National Petroleum Reserve in Alaska (NPRA) are a focus of exploration since the 1994 discovery of the nearby Alpine oil field (>400 MMBO). These strata include the Kingak Shale, a succession of depositional sequences influenced by rift opening of the Arctic Ocean Basin. Interpretation of sequence stratigraphy and depositional facies from a regional two-dimensional seismic grid and well data allows the definition of four sequence sets that each displays unique stratal geometries and thickness trends across NPRA. A Lower to Middle Jurassic sequence set includes numerous transgressive-regressive sequences that collectively built a clastic shelf in north-central NPRA. Along the south-facing, lobate shelf margin, condensed shales in transgressive systems tracts downlap and coalesce into a basinal condensed section that is likely an important hydrocarbon source rock. An Oxfordian-Kimmeridgian sequence set, deposited during pulses of uplift on the Barrow arch, includes multiple transgressive-regressive sequences that locally contain well-winnowed, shoreface sandstones at the base of transgressive systems tracts. These shoreface sandstones and overlying shales, deposited during maximum flooding, form stratigraphic traps that are the main objective of exploration in the Alpine play in NPRA. A Valanginian sequence set includes at least two transgressive-regressive sequences that display relatively distal characteristics, suggesting high relative sea level. An important exception is the presence of a basal transgressive systems tract that locally contains shoreface sandstones of reservoir quality. A Hauterivian sequence set includes two transgressive-regressive sequences that constitute a shelf-margin wedge developed as the result of tectonic uplift along the Barrow arch during rift opening of the Arctic Ocean Basin. This sequence set displays stratal geometries suggesting incision and synsedimentary collapse of the shelf

  6. Tectonic evolution of the Malay Peninsula inferred from Jurassic to Cretaceous paleomagnetic results

    Science.gov (United States)

    Otofuji, Yo-ichiro; Moriyama, Yuji T.; Arita, Maiko P.; Miyazaki, Masanari; Tsumura, Kosuke; Yoshimura, Yutaka; Shuib, Mustaffa Kamal; Sone, Masatoshi; Miki, Masako; Uno, Koji; Wada, Yutaka; Zaman, Haider

    2017-02-01

    A primary remanent magnetization is identified in the Jurassic-Cretaceous red bed sandstones of the Tembeling Group in Peninsular Malaysia. This high-temperature magnetic component is unblocked at 680-690 °C, revealing a clockwise deflected direction of Ds = 56.8°, Is = 31.6° (where ks = 8.5, α95 = 11.3° and N = 22) in stratigraphic coordinates. The primary origin of this component is ascertained by a positive fold test and a geomagnetic polarity reversal in the Kuala Wau section. Secondary remanent magnetizations are identified in the rocks of the Tembeling and Bertangga basins, which indicate a counter-clockwise deflection in the geographic coordinates (Dg = 349.1°, Ig = 15.3° where kg = 11.8, α95 = 5.1°, N = 72). The comparison with the expected paleomagnetic directions from the 130 Ma and 40 Ma Eurasian poles indicates two-stages of tectonic movement in the southern Malay Peninsula: (1) a clockwise rotation of 61.1° ± 11.9° accompanied by a 13.3° ± 8.1° southward displacement after the Cretaceous; and (2) a subsequent counter-clockwise rotation of 18.5° ± 5.0° to the present day position. The first stage of rotation is ascribed to tectonic deformation caused by the indentation of India into Asia after 55 Ma, while the second stage is attributed to the collision of the Australian Plate with SE Asia after 30-20 Ma. The present paleomagnetic results from the Jurassic-Cretaceous Tembeling Group thus reveal impacts of both of these collisions on SE Asia in general and on Peninsular Malaysia in particular.

  7. Virtual reconstruction of the endocranial anatomy of the early Jurassic marine crocodylomorph Pelagosaurus typus (Thalattosuchia

    Directory of Open Access Journals (Sweden)

    Stephanie E. Pierce

    2017-04-01

    Full Text Available Thalattosuchians were highly specialised aquatic archosaurs of the Jurassic and Early Cretaceous, and represent a peak of aquatic adaptation among crocodylomorphs. Relatively little is known of their endocranial anatomy or its relevance for the evolution of sensory systems, physiology, and other aspects of biology. Nevertheless, such data have significance for two reasons: (1 thalattosuchians represent an important data point regarding adaptation to marine life in tetrapods; and (2 as early-diverging members of the crocodylian stem-lineage, thalattosuchians provide information on the evolutionary assembly of the brain and other endocranial structures in crocodylomorphs. Here we use µCT data to virtually reconstruct the endocranial anatomy of Pelagosaurus typus, an early thalattosuchian with plesiomorphic traits of relevance to the split between the two major subgroups: Teleosauroidea and Metriorhynchoidea. Interpretation of these data in a broad comparative context indicate that several key endocranial features may be unique to thalattosuchians, including: a pyramidal morphology of the semicircular canals, the presence of an elongate endosseous cochlear duct that may indicate enhanced hearing ability, the presence of large, paired canals extending anteriorly from an enlarged pituitary fossa, a relatively straight brain (possibly due to the presence of large, laterally placed orbits, and an enlarged venous sinus projecting dorsally from the endocast that is confluent with the paratympanic sinus system. Notably, we document a large expansion of the nasal cavity anterior to the orbits in Pelagosaurus as an osteological correlate of an enlarged salt gland previously only documented in Late Jurassic metriorhynchoids. This is the first anatomical evidence of this structure in early thalattosuchians. Pelagosaurus also shares the presence of paired olfactory bulbs with metriorhynchoids, and shows an enlarged cerebrum, which may also be present in

  8. Cold seep-related occurrence of the Early Jurassic rhynchonellid brachiopod Anarhynchia from the Canadian Cordillera

    Science.gov (United States)

    Pálfy, József; Price, Gregory D.; Vörös, Attila; Kovács, Zsófia; Johannson, Gary G.

    2017-04-01

    Cold seeps, where seepage of methane and/or other hydrocarbon-rich fluids and hydrogen-sulfide occurs in the sea floor, are sites which harbor highly specialized ecosystems associated with distinctive carbonate sediments. Although their Mesozoic record is scarce and patchy, it commonly includes rhynchonellid brachiopods, often of large size. Each new occurrence is valuable in filling gaps and providing additional insight into these peculiar ecosystems. Here we report a monospecific assemblage of Anarhynchia from a boulder-sized limestone clast of Early Pliensbachian (Early Jurassic) age in the Inklin Formation of the Whitehorse Trough in Stikine terrane, recovered from a locality at Copper Island in Atlin Lake, northern British Columbia, Canada. Specimens are of unusually large size, up to 9 cm in length, and their external and internal morphology allows assignment to Anarhynchia but warrants introduction of a new species. Although d13C and d18O values of the shells are close to equilibrium with ancient seawater, early precipitated carbonate cement phases of the enclosing limestone are characterised by highly depleted carbon isotopic composition, indicative of the influence of microbial oxidation of methane derived from a cold seep. Carbonate petrography of the isopachous, banded-fibrous cement supports its origin in a cold seep environment. Volcanogenic detrital grains in the micritic matrix of the limestone clast are indistinguishable from those in the sandstone layers in the siliciclastic sequence, suggesting that the seep carbonate is broadly coeval with the enclosing conglomerate. Previously, Anarhynchia has been known from the Lower Jurassic of California and Oregon, from both cold seep and hydrothermal vent deposits. Our new record extends the geographic range and species-level diversity of the genus, but supports its endemism to the East Pacific and membership in chemosynthesis-based ecosystems.

  9. Magnetostratigraphy of the middle-upper Jurassic sedimentary sequences at Yanshiping, Qiangtang Basin, China

    Science.gov (United States)

    Song, Chunhui; Zeng, Yongyao; Yan, Maodu; Wu, Song; Fang, Xiaomin; Bao, Jing; Zan, Jinbo; Liu, Xifang

    2016-09-01

    A series of important geological events occurred in the Tibetan Plateau area during the Jurassic, such as the collision of the Lhasa and Qiangtang Terranes, the closure of the Meso-Tethyan Ocean, the opening of the Neo-Tethyan Ocean and the cessation of the mega-monsoon. The ˜3000 m thick Jurassic sedimentary sequence in the Qiangtang Basin on the central Tibetan Plateau, which is called the Yanshiping (YSP) Group, recorded these geological events. However, the chronology of the sequence is surprisingly poorly constrained. Here, we perform a detailed palaeomagnetic analysis on the ˜1060 m thick middle and upper portions of the YSP Group (the Xiali and Suowa Formations) in the YSP section of the eastern Qiangtang Basin. Three bivalve zones at stratigraphic intervals of ˜40-140, 640-800 and 940-1040 m are identified, which yield a Bathonian-Callovian age for the Lower Xiali Fm., a Callovian-Oxfordian age for the Lower Suowa Fm. and an Oxfordian-Kimmeridgian age for the Upper Suowa Fm. A total of 544 oriented palaeomagnetic samples were collected from the section. By combining thermal and alternating field demagnetizations, clear characteristic remanent magnetization (ChRM) directions are isolated for most of the samples. The robust ChRM directions pass fold and reversals tests, which support the primary nature of the ChRMs and yield a palaeopole at 76.8°N/297.2°E (dp = 2.2°, dm = 3.7°). A total of 27 normal and 26 reversed polarity zones were successfully recorded in the section. Combined with fossil age constraints, results suggest that the section is plausibly composed of a Callovian-Early Kimmeridgian age sedimentary sequence.

  10. Jurassic evaporite facies of the Afghan-Tajik and Amu Darya basins in northern Afghanistan and adjacent areas (evapfacafg.shp)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile contains polygons that describe the spatial extent of Jurassic age evaporite facies (Gaurdak formation) in the Afghan-Tajik and Amu Darya basins.

  11. Combined oxygen- and carbon-isotope records through the Early Jurassic: multiple global events and two modes of carbon-cycle/temperature coupling

    DEFF Research Database (Denmark)

    Hesselbo, Stephen P.; Korte, Christoph

    2010-01-01

    The Jurassic comprises some 55 million years of Earth history. However, within the Jurassic, only one major environmental change (hyperthermal) event is really well known - the Early Toarcian Oceanic Anoxic Event (OAE) at ~183 Ma - and until very recently the extent to which the accompanying...... environmental changes were global has been strongly debated. Nevertheless, partly as a result of the international effort to define Global Stratotype Sections and Points (GSSPs), much more is now being discovered about environmental changes taking place at and around the other Jurassic Age (Stage) boundaries......, to the extent that meaningful comparisons between these events can begin to be made. Here we present new carbon and oxygen isotope data from mollusks (bivalves and belemnites) and brachiopods collected through the marine Early Jurassic succession of NE England, including the Sinemurian-Plienbachian boundary...

  12. Thickness of Jurassic evaporite facies in the Afghan-Tajik and Amu Darya basins of northern Afghanistan and adjacent areas (evapisoafg.shp)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This shapefile contains polylines (isopachs) that describe the thickness of Jurassic age evaporite facies (Gaurdak formation) in the Afghan-Tajik and Amu Darya basins

  13. New occurrences of the wood Protocupressinoxylon purbeckensis Francis: implications for terrestrial biomes in southwestern Europe at the Jurassic/Cretaceous boundary

    National Research Council Canada - National Science Library

    Philippe, Marc; Billon-Bruyat, Jean-Paul; Garcia-Ramos, Jose C; Bocat, Loic; Gomez, Bernard; Pinuela, Laura

    2010-01-01

    ... (Kimmeridgian sensu anglico- Portlandian). The review of fossil wood data indicates that such a stressful environment may have constrained terrestrial biocoenoses and their evolution at the Jurassic/Cretaceous boundary...

  14. Radiometric Dating of Ignimbrite from Inner Mongolia Provides no Indication of a Post-Middle Jurassic Age for the Daohugou Beds

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being postMiddle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the postMiddle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed.

  15. Jurassic-Cretaceous Composite Total Petroleum System and Geologic Assessment of Oil and Gas Resources of the North Cuba Basin, Cuba

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) recently completed an assessment of the undiscovered oil and gas resources of the Jurassic-Cretaceous Composite Total Petroleum...

  16. When dinosaurs ruled the earth? Digital animals, simulation, and the return of ‘real nature’ in the Jurassic Park movies

    OpenAIRE

    Fuchs, Michael

    2016-01-01

    This essay argues that the digital reanimation of dinosaurs in the Jurassic Park series not only epitomizes mankind’s tortured relationship with other animal species on this planet, but also demonstrates how technology transforms animals into spectral post-animal beings. Both in its diegesis and in its production, the Jurassic Park movie franchise emblematizes humanity’s compulsive desire to control the rest of the planet. This desire has culminated in the most recent addition to the series, ...

  17. Chapter 2. Assessment of undiscovered conventional oil and gas resources--Upper Jurassic-Lower Cretaceous Cotton Valley group, Jurassic Smackover interior salt basins total petroleum system, in the East Texas basin and Louisiana-Mississippi salt basins provinces.

    Science.gov (United States)

    Dyman, T.S.; Condon, S.M.

    2006-01-01

    The Jurassic Smackover Interior Salt Basins Total Petroleum System is defined for this assessment to include (1) Upper Jurassic Smackover Formation carbonates and calcareous shales and (2) Upper Jurassic and Lower Cretaceous Cotton Valley Group organic-rich shales. The Jurassic Smackover Interior Salt Basins Total Petroleum System includes four conventional Cotton Valley assessment units: Cotton Valley Blanket Sandstone Gas (AU 50490201), Cotton Valley Massive Sandstone Gas (AU 50490202), Cotton Valley Updip Oil and Gas (AU 50490203), and Cotton Valley Hypothetical Updip Oil (AU 50490204). Together, these four assessment units are estimated to contain a mean undiscovered conventional resource of 29.81 million barrels of oil, 605.03 billion cubic feet of gas, and 19.00 million barrels of natural gas liquids. The Cotton Valley Group represents the first major influx of clastic sediment into the ancestral Gulf of Mexico. Major depocenters were located in south-central Mississippi, along the Louisiana-Mississippi border, and in northeast Texas. Reservoir properties and production characteristics were used to identify two Cotton Valley Group sandstone trends across northern Louisiana and east Texas: a high-permeability blanket-sandstone trend and a downdip, low-permeability massive-sandstone trend. Pressure gradients throughout most of both trends are normal, which is characteristic of conventional rather than continuous basin-center gas accumulations. Indications that accumulations in this trend are conventional rather than continuous include (1) gas-water contacts in at least seven fields across the blanket-sandstone trend, (2) relatively high reservoir permeabilities, and (3) high gas-production rates without fracture stimulation. Permeability is sufficiently low in the massive-sandstone trend that gas-water transition zones are vertically extensive and gas-water contacts are poorly defined. The interpreted presence of gas-water contacts within the Cotton Valley

  18. Square-wave anodic-stripping voltammetric determination of Cd, Pb, and Cu in a hydrofluoric acid solution of siliceous spicules of marine sponges (from the Ligurian Sea, Italy, and the Ross Sea, Antarctica)

    Energy Technology Data Exchange (ETDEWEB)

    Truzzi, C.; Annibaldi, A.; Illuminati, S.; Bassotti, E.; Scarponi, G. [Polytechnic University of Marche, Ancona (Italy). Department of Marine Science

    2008-09-15

    Square-wave anodic-stripping voltammetry (SWASV) was set up and optimized for simultaneous determination of cadmium, lead, and copper in siliceous spicules of marine sponges, directly in the hydrofluoric acid solution ({proportional_to}0.55 mol L{sup -1} HF, pH {proportional_to}1.9). A thin mercury-film electrode (TMFE) plated on to an HF-resistant epoxy-impregnated graphite rotating-disc support was used. The optimum experimental conditions, evaluated also in terms of the signal-to-noise ratio, were as follows: deposition potential -1100 mV vs. Ag/AgCl, KCl 3 mol L{sup -1}, deposition time 3-10 min, electrode rotation 3000 rpm, SW scan from -1100 mV to +100 mV, SW pulse amplitude 25 mV, frequency 100 Hz, {delta}E{sub step} 8 mV, t{sub step} 100 ms, t{sub wait} 60 ms, t{sub delay} 2 ms, t{sub meas} 3 ms. Under these conditions the metal peak potentials were Cd -654{+-}1 mV, Pb -458 {+-} 1 mV, Cu -198{+-}1 mV. The electrochemical behaviour was reversible for Pb, quasi-reversible for Cd, and kinetically controlled (possibly following chemical reaction) for Cu. The linearity of the response with concentration was verified up to {proportional_to}4 {mu}g L{sup -1} for Cd and Pb and {proportional_to}20 {mu}g L{sup -1} for Cu. The detection limits were 5.8 ng L{sup -1}, 3.6 ng L{sup -1}, and 4.3 ng L{sup -1} for Cd, Pb, and Cu, respectively, with t{sub d}=5 min. The method was applied for determination of the metals in spicules of two specimens of marine sponges (Demosponges) from the Portofino natural reserve (Ligurian Sea, Italy, Petrosia ficiformis) and Terra Nova Bay (Ross Sea, Antarctica, Sphaerotylus antarcticus). The metal contents varied from tens of ng g{sup -1} to {proportional_to}1 {mu}g g{sup -1}, depending on the metal considered and with significant differences between the two sponge species. (orig.)

  19. Cretaceous and Jurassic intrusions in Crimean Mountains: The first data of U-Pb (SIMS SHRIMP) dating

    Science.gov (United States)

    Morozova, E. B.; Sergeev, S. A.; Savelev, A. D.

    2017-05-01

    U-Pb geochronological studies of igneous rocks of the Crimean Mountains were carried out for the first time. The ages of magma crystallization determined for gabbro-dolerites of the Dzhidair and Pervomaiskii intrusions point to the injection of these rocks during the Middle Jurassic Aalenian-Bajocian stage of magmatism. The Berriasian-Valanginian and Aptian age of sill-like bodies within the mass of volcanogenic-sedimentary rocks presumes the necessity to reconsider the common notion of an exclusively Albian magmatic event during the Cretaceous. High-precision U-Pb dating of magma intrusions allowed us to verify the age of Middle Jurassic magmatism and to distinguish the new Early Cretaceous Berriasian-Valanginian magmatism stage of basic composition.

  20. Upper Jurassic and Lower Cretaceous of Sanjiang-Middle Amur basin: Non-marine and marine correlation

    Institute of Scientific and Technical Information of China (English)

    KIRILLOVA; Galina

    2009-01-01

    A comparative analysis of Late Jurassic-Early Cretaceous strata have been done for the Sanjiang Middle Amur basin, a coaland oil-bearing area spanning the eastern Heilongjiang of northeastern China and southeastern Far East of Russia. On the basis of various fossils occurring in the formations, particularly by means of the Tithonian-Valanginian index Buchia and the late Barremian-middle Albian indicator Aucellina assemblages, the marine and non-marine Late Jurassic-Early Cretaceous strata in the basin are correlated. The Mesozoic international chronostratigraphic chart (http://www.stratigra phy.org) is established basically based on the marine rocks. To accurately date the non-marine strata, it is necessary to correlate them with the marine deposits. This study sheds new light on the dating and correlation of non-marine Upper Mesozoic. Additionally, the results would help understand the tectonics and paleogeography and thus aid the exploration of energy resources.

  1. A Quantitative Study on Paleo—River Environment During Late Jurassic on yaojie Region,Minhe Basin

    Institute of Scientific and Technical Information of China (English)

    邵树勋; 燕永峰; 等

    2000-01-01

    Fluvial Sedimentation of alluvial facies prevailed during the Late Jrassic in the Minhe Basin.On the basis of the study of sedimentary facies of the Upper Jurassic series.this paper focuses on the river types suing the "Architecture Element" analysis method proposed by Miall,and calculated all the quantitative parameters to reflect the characteristics of the stream channel geometry and hydrodynamic conditions of paleo-rivers with the equations of ethrideg,schumm et al.Finally,we discussed the characteristics of environmental evolution of palsorivers on the quantitative basis.Our conclusion indicates that the evolution of paleo-rivers during the Late Jurassic,from early to late,shows such a tendency as alluvial fan river→ braid river→alluvial fan river→mid-sinuoisty river→ high-sinuosity river.

  2. Thermal and maturation history of Jurassic source rocks in the Kuqa foreland depression of Tarim Basin, NW China

    Science.gov (United States)

    Tang, Xiaoyin; Yang, Shuchun; Hu, Shengbiao

    2014-08-01

    Kuqa foreland depression of the Tarim Basin is one of the largest gas production provinces in China. Thermal history reconstruction using vitrinite reflectance data indicates that the palaeo-heat flow in Kuqa depression was relatively high (50-55 mW/m2) during the Mesozoic, but gradually decreased during the Cenozoic to reach the present value of 40-50 mW/m2. The cooling of the Kuqa depression is probably attributed to the crust thickening and the rapid sedimentary rate. The Jurassic source rocks entered conventional oil window at 100 Ma, and began to generate gas at approximately 75 Ma in the Kelasu area. Thermal maturation of the Jurassic source rocks accelerated significantly since 23.3 Ma, especially in the recent 5.2 Ma. In this foreland depression, source rock maturation, which is likely controlled mainly by burial history, also influenced by the presence of fault thrusting and salt-bearing formations.

  3. Jurassic onychites (arm hooks) from squid-like cephalopods from the Wessex Basin, southern England

    Science.gov (United States)

    Hart, Malcolm; Hughes, Zoe; Page, Kevin; Price, Gregory; Smart, Christopher

    2017-04-01

    of hook that are often arranged in pairs. Using the abundance of material available to us from the Wessex Basin, we are attempting to identify the host animals wherever this is possible. If this can be established then it may be possible, using micropalaeontological samples, to determine the stratigraphical and palaeoecological ranges of some of the host macro-fossils, many of which are otherwise rarely preserved outside known lagerstätte. A recently described specimen (Bristol Museum and Art Gallery, BRMSG Ce12385) of only the hooks associated with 4 arms can, therefore, be attributed to the Clarkeiteuthis lineage. Coming from the Lower Pliensbachian of the Dorset Coast this occurrence falls in the stratigraphical 'gap' between the known taxa of the Sinemurian (Clarkeiteuthis montefiore) and the Toarcian (Clarkeiteuthis conocauda). This specimen does, however, show paired hooks of different types, similar to another specimen in Manchester University Museum: this is not seen in C. conocauda and places the specimen in C. montefiore or a yet undescribed species of Clarkeiteuthis. Engeser, T.S. & Clarke, M.R. 1988. Cephalopod hooks, both recent and fossil. In: Clarke, M.R. & Trueman, E.R. (eds), Palaeontology and Neontology of Cephalopods, vol. 12,; Wilbur, K.M. (Ed.), The Mollusca, Academic press Inc., London, 133-151. Hart, M.B. & Hutchinson, D. in press. A newly described 'clarkeiteuthid' from the Lias Group of Dorset. Geoscience in South-West England. Hart, M.B., De Jonghe, A., Page, K.N., Price, G.D. & Smart, C.W. 2016. Exceptional accumulations of statoliths in association with the Christian Malford lagerstätte (Callovian, Jurassic) in Wiltshire, United Kingdom. Palaios, 31, 203-220. Kulicki, C. & Szaniawski, H. 1972. Cephalopod arm hooks from the Jurassic of Poland. Acta Palaeontologica Polonica, 17, 379-419. Wilby, P.R., Hudson, J.D., Clements, R.G. & Hollingworth, N.T.J. 2004. Taphonomy and origin of an accumulate of soft-bodied cephalopods in the Oxford Clay

  4. Reconstruction of the Upper Jurassic Morrison Formation extinct ecosystem—a synthesis

    Science.gov (United States)

    Turner, Christine E.; Peterson, Fred

    2004-05-01

    A synthesis of recent and previous studies of the Morrison Formation and related beds, in the context of a conceptual climatic/hydrologic framework, permits reconstruction of the Late Jurassic dinosaurian ecosystem throughout the Western Interior of the United States and Canada. Climate models and geologic evidence indicate that a dry climate persisted in the Western Interior during the Late Jurassic. Early and Middle Kimmeridgian eolian deposits and Late Kimmeridgian alkaline, saline wetland/lacustrine deposits demonstrate that dryness persisted throughout the Kimmeridgian. Tithonian-age coal reflects lower evaporation rates associated with a slight cooling trend, but not a significant climate change. With a subtropical high over the Paleo-Pacific Ocean and atmospheric circulation generally toward the east, moisture carried by prevailing winds "rained out" progressively eastward, leaving the continental interior—and the Morrison depositional basin—dry. Within the basin, high evaporation rates associated with the southerly paleolatitude and greenhouse effects added to the dryness. Consequently, the two main sources of water—groundwater and surface water—originated outside the basin, through recharge of regional aquifers and streams that originated in the western uplands. Precipitation that fell west of the basin recharged aquifers that underlay the basin and discharged in wetlands and lakes in the distal, low-lying part of the basin. Precipitation west of the basin also fed intermittent and scarce perennial streams that flowed eastward. The streams were probably "losing" streams in their upstream reaches, and contributed to a locally raised water table. Elsewhere in the basin, where the floodplain intersected the water table, small lakes dotted the landscape. Seasonal storms, perhaps in part from the Paleo-Gulf of Mexico, brought some precipitation directly to the basin, although it was also subjected to "rain out" en route. Thus, meteoric input to the

  5. Reconstruction of the Upper Jurassic Morrison Formation extinct ecosystem - A synthesis

    Science.gov (United States)

    Turner, C.E.; Peterson, F.

    2004-01-01

    A synthesis of recent and previous studies of the Morrison Formation and related beds, in the context of a conceptual climatic/hydrologic framework, permits reconstruction of the Late Jurassic dinosaurian ecosystem throughout the Western Interior of the United States and Canada. Climate models and geologic evidence indicate that a dry climate persisted in the Western Interior during the Late Jurassic. Early and Middle Kimmeridgian eolian deposits and Late Kimmeridgian alkaline, saline wetland/lacustrine deposits demonstrate that dryness persisted throughout the Kimmeridgian. Tithonian-age coal reflects lower evaporation rates associated with a slight cooling trend, but not a significant climate change. With a subtropical high over the Paleo-Pacific Ocean and atmospheric circulation generally toward the east, moisture carried by prevailing winds "rained out" progressively eastward, leaving the continental interior-and the Morrison depositional basin-dry. Within the basin, high evaporation rates associated with the southerly paleolatitude and greenhouse effects added to the dryness. Consequently, the two main sources of water-groundwater and surface water-originated outside the basin, through recharge of regional aquifers and streams that originated in the western uplands. Precipitation that fell west of the basin recharged aquifers that underlay the basin and discharged in wetlands and lakes in the distal, low-lying part of the basin. Precipitation west of the basin also fed intermittent and scarce perennial streams that flowed eastward. The streams were probably "losing" streams in their upstream reaches, and contributed to a locally raised water table. Elsewhere in the basin, where the floodplain intersected the water table, small lakes dotted the landscape. Seasonal storms, perhaps in part from the Paleo-Gulf of Mexico, brought some precipitation directly to the basin, although it was also subjected to "rain out" en route. Thus, meteoric input to the basin was

  6. Coal petrology and genesis of Jurassic coal in the Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Weihua Ao

    2012-01-01

    Full Text Available Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin, northwestern China. The huge reserves of this high quality coal have a high commercial value. We studied the coal’s petrologic characteristics and its maceral distribution to determine the maceral’s contribution to generation of oil and gas. The results show that the Jurassic coals in the Ordos Basin have special petrological features because of the Basin’s unique depositional environment which was mainly a series of high-stand swamps in the upper fluvial system. These petrographic features are a result of the development of typical inland lakes where some sand bodies were formed by migrating rivers. After burial, the peat continued to undergo oxidizing conditions, this process generated extensive higher inertinite contents in the coals and the vitrinite components were altered to semi-vitrinite. The macroscopic petrographic types of these Jurassic coals are mainly semi-dull coal, dull coal, semilustrous and lustrous coal. The proportions of semi-dull coal and dull coal are higher in the basin margins, especially in the area near the northern margin. The numbers of semilustrous and lustrous coals increase southwards and towards the central basin. This situation indicates that different coal-forming swamp environments have major controlling effects on the coal components. Another observation is that in the Ordos’ coal sequences, especially in the lower part, some sandstone beds are thick, up to 20 m with a coarse grain size. The higher fusinite content in the macerals accompanies a higher semi-vitrinite content with more complete and regular plant cell structure. The fusinite structure is clear and well preserved. After burial, the lithology of the roof and floor rocks can continue to affect the evolution of coal petrology. The sand bodies in the roof and floor exhibit good

  7. Conchostracans as evidence of Jurassic levels in the Caturrita Formation, Faxinal do Soturno, Rio Grande do Sul, Brazi

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    Rosemarie Rohn

    2014-03-01

    Full Text Available This paper focus on the first conchostracans (Crustacea, Spinicaudata found at the São Luís outcrop (Caturrita Formation, Rosário do Sul Group, in Faxinal do Soturno, Rio Grande do Sul State, Brazil (29º33’ 29.09”S, 53º 26’ 54”W. Fossil vertebrates and plants identified at this outcrop suggest conflicting ages, respectively Late Triassic and Early Jurassic. Dinosaur tracks recently found at the upper part of the outcrop enhance these age problems. In this way, the conchostracans constitute important additional elements in this discussion. Some specimens share many characteristics with Carapacestheria disgregaris (Tasch Shen (Eosestheriidae of the Ferrar Group, Lower-Mid Jurassic of the Transantartic Mountains. But differences in the ornamentation details led to the proposal of a new genus and a new species, Nothocarapacestheria soturnensis , and to the interpretation of a close phylogenetic relationship with the Antarctic species. Other samples in this assemblage are similar to Australestheria corneti (Marliére Chen (Fushunograptidae of the Middle Jurassic from Zaire. Together, these conchostracans substantiate a Jurassic age and corroborate the data of the Bennettitales flora found at the same levels in the outcrop. However, the Late Triassic age indicated by the tetrapods cannot be discarded according to their lower stratigraphic position in São Luís outcrop. In the same way, the present chronostratigraphic discussion does not apply to the other occurrences of the Caturrita Formation, especially because the correlations between outcrops are extremely difficult, both by the lack of paleontological support and by the numerous faultings during the Mesozoic sedimentation in the southern part of the Paraná Basin.

  8. Possible trace fossils of putative termite origin in the Lower Jurassic (Karoo Supergroup of South Africa and Lesotho

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    O. Catuneanu

    2010-01-01

    Full Text Available Complex structures in the sandstones of the Lower Jurassic aeolian Clarens Formation (Karoo Supergroup are found at numerous localities throughout southern Africa, and can be assigned to five distinct architectural groups: (1 up to 3.3-m high, free-standing, slab-shaped forms of bioturbated sandstones with elliptical bases, orientated buttresses and an interconnecting large burrow system; (2 up to 1.2-m high, free-standing, irregular forms of bioturbated sandstones with 2-cm to 4-cm thick, massive walls, empty chambers and vertical shafts; (3 about 0.15-m to 0.25-m high, mainly bulbous, multiple forms with thin walls (larger than 2 cm, hollow chambers with internal pillars and bridges; (4 about 0.15-m to 0.2-m (maximum 1-m high, free-standing forms of aggregated solitary spheres associated with massive horizontal, orientated capsules or tubes, and meniscate tubes; and (5 about 5 cmin diameter, ovoid forms with weak internal shelving in a close-fitting cavity. Based on size, wall thickness, orientation and the presence of internal chambers, these complex structures are tentatively interpreted as ichnofossils of an Early Jurassic social organism; the different architectures are reflective of the different behaviours of more than one species, the history of structural change in architectural forms (ontogenetic series or an architectural adaptation to local palaeoclimatic variability. While exact modern equivalents are unknown, some of these ichnofossils are comparable to nests (or parts of nests constructed by extant termites, and thus these Jurassic structures are very tentatively interpreted here as having been made by a soil-dwelling social organism, probably of termite origin. This southern African discovery, along with reported Triassic and Jurassic termite ichnofossils from North America, supports previous hypotheses that sociality in insects, particularity in termites, likely evolved prior to the Pangea breakup in the Early Mesozoic.

  9. The first metriorhynchid crocodylomorph from the Middle Jurassic of Spain, with implications for evolution of the subclade Rhacheosaurini.

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    Jara Parrilla-Bel

    Full Text Available BACKGROUND: Marine deposits from the Callovian of Europe have yielded numerous species of metriorhynchid crocodylomorphs. While common in English and French Formations, metriorhynchids are poorly known from the Iberian Peninsula. Twenty years ago an incomplete, but beautifully preserved, skull was discovered from the Middle Callovian of Spain. It is currently the oldest and best preserved metriorhynchid specimen from the Iberian Peninsula. Until now it has never been properly described and its taxonomic affinities remained obscure. METHODOLOGY/PRINCIPAL FINDINGS: Here we present a comprehensive description for this specimen and in doing so we refer it to a new genus and species: Maledictosuchus riclaensis. This species is diagnosed by numerous autapomorphies, including: heterodont dentition; tightly interlocking occlusion; lachrymal anterior process excludes the jugal from the preorbital fenestra; orbits longer than supratemporal fenestrae; palatine has two non-midline and one midline anterior processes. Our phylogenetic analysis finds Maledictosuchus riclaensis to be the basal-most known member of Rhacheosaurini (the subclade of increasingly mesopelagic piscivores that includes Cricosaurus and Rhacheosaurus. CONCLUSIONS/SIGNIFICANCE: Our description of Maledictosuchus riclaensis shows that the craniodental morphologies that underpinned the success of Rhacheosaurini in the Late Jurassic and Early Cretaceous, as a result of increasing marine specialization to adaptations for feeding on fast small-bodied prey (i.e. divided and retracted external nares; reorientation of the lateral processes of the frontal; elongate, tubular rostrum; procumbent and non-carinated dentition; high overall tooth count; and dorsolaterally inclined paroccipital processes, first appeared during the Middle Jurassic. Rhacheosaurins were curiously rare in the Middle Jurassic, as only one specimen of Maledictosuchus riclaensis is known (with no representatives discovered from

  10. New ophthalmosaurid ichthyosaurs from the European Lower Cretaceous demonstrate extensive ichthyosaur survival across the Jurassic-Cretaceous boundary.

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    Valentin Fischer

    Full Text Available BACKGROUND: Ichthyosauria is a diverse clade of marine amniotes that spanned most of the Mesozoic. Until recently, most authors interpreted the fossil record as showing that three major extinction events affected this group during its history: one during the latest Triassic, one at the Jurassic-Cretaceous boundary (JCB, and one (resulting in total extinction at the Cenomanian-Turonian boundary. The JCB was believed to eradicate most of the peculiar morphotypes found in the Late Jurassic, in favor of apparently less specialized forms in the Cretaceous. However, the record of ichthyosaurs from the Berriasian-Barremian interval is extremely limited, and the effects of the end-Jurassic extinction event on ichthyosaurs remains poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Based on new material from the Hauterivian of England and Germany and on abundant material from the Cambridge Greensand Formation, we name a new ophthalmosaurid, Acamptonectes densus gen. et sp. nov. This taxon shares numerous features with Ophthalmosaurus, a genus now restricted to the Callovian-Berriasian interval. Our phylogenetic analysis indicates that Ophthalmosauridae diverged early in its history into two markedly distinct clades, Ophthalmosaurinae and Platypterygiinae, both of which cross the JCB and persist to the late Albian at least. To evaluate the effect of the JCB extinction event on ichthyosaurs, we calculated cladogenesis, extinction, and survival rates for each stage of the Oxfordian-Barremian interval, under different scenarios. The extinction rate during the JCB never surpasses the background extinction rate for the Oxfordian-Barremian interval and the JCB records one of the highest survival rates of the interval. CONCLUSIONS/SIGNIFICANCE: There is currently no evidence that ichthyosaurs were affected by the JCB extinction event, in contrast to many other marine groups. Ophthalmosaurid ichthyosaurs remained diverse from their rapid radiation in the Middle

  11. Discontinuities Characteristics of the Upper Jurassic Arab-D Reservoir Equivalent Tight Carbonates Outcrops, Central Saudi Arabia

    Science.gov (United States)

    Abdlmutalib, Ammar; Abdullatif, Osman

    2017-04-01

    Jurassic carbonates represent an important part of the Mesozoic petroleum system in the Arabian Peninsula in terms of source rocks, reservoirs, and seals. Jurassic Outcrop equivalents are well exposed in central Saudi Arabia and which allow examining and measuring different scales of geological heterogeneities that are difficult to collect from the subsurface due to limitations of data and techniques. Identifying carbonates Discontinuities characteristics at outcrops might help to understand and predict their properties and behavior in the subsurface. The main objective of this study is to identify the lithofacies and the discontinuities properties of the upper Jurassic carbonates of the Arab D member and the Jubaila Formation (Arab-D reservoir) based on their outcrop equivalent strata in central Saudi Arabia. The sedimentologic analysis revealed several lithofacies types that vary in their thickness, abundances, cyclicity and vertical and lateral stacking patterns. The carbonates lithofacies included mudstone, wackestone, packstone, and grainstone. These lithofacies indicate deposition within tidal flat, skeletal banks and shallow to deep lagoonal paleoenvironmental settings. Field investigations of the outcrops revealed two types of discontinuities within Arab D Member and Upper Jubaila. These are depositional discontinuities and tectonic fractures and which all vary in their orientation, intensity, spacing, aperture and displacements. It seems that both regional and local controls have affected the fracture development within these carbonate rocks. On the regional scale, the fractures seem to be structurally controlled by the Central Arabian Graben System, which affected central Saudi Arabia. While, locally, at the outcrop scale, stratigraphic, depositional and diagenetic controls appear to have influenced the fracture development and intensity. The fracture sets and orientations identified on outcrops show similarity to those fracture sets revealed in the upper

  12. New dinosaur (Theropoda, stem-Averostra) from the earliest Jurassic of the La Quinta formation, Venezuelan Andes.

    Science.gov (United States)

    Langer, Max C; Rincón, Ascanio D; Ramezani, Jahandar; Solórzano, Andrés; Rauhut, Oliver W M

    2014-10-01

    Dinosaur skeletal remains are almost unknown from northern South America. One of the few exceptions comes from a small outcrop in the northernmost extension of the Andes, along the western border of Venezuela, where strata of the La Quinta Formation have yielded the ornithischian Laquintasaura venezuelae and other dinosaur remains. Here, we report isolated bones (ischium and tibia) of a small new theropod, Tachiraptor admirabilis gen. et sp. nov., which differs from all previously known members of the group by an unique suite of features of its tibial articulations. Comparative/phylogenetic studies place the new form as the sister taxon to Averostra, a theropod group that is known primarily from the Middle Jurassic onwards. A new U-Pb zircon date (isotope dilution thermal-ionization mass spectrometry; ID-TIMS method) from the bone bed matrix suggests an earliest Jurassic maximum age for the La Quinta Formation. A dispersal-vicariance analysis suggests that such a stratigraphic gap is more likely to be filled by new records from north and central Pangaea than from southern areas. Indeed, our data show that the sampled summer-wet equatorial belt, which yielded the new taxon, played a pivotal role in theropod evolution across the Triassic-Jurassic boundary.

  13. Presence of the dinosaur Scelidosaurus indicates Jurassic age for the Kayenta Formation (Glen Canyon Group, northern Arizona)

    Science.gov (United States)

    Padian, Kevin

    1989-05-01

    The Glen Canyon Group (Moenave, Wingate, Kayenta and Navajo Formations) of northern Arizona represents an extensive outcrop of early Mesozoic age terrestrial sediments. The age of these formations has long been disputed because independent stratigraphic data from marine tie-ins, paleobotanical and palynological evidence, and radiometric calibrations have been scanty or absent. The fauna of the Kayenta Formation in particular has been problematic because it has appeared to contain both typical Late Triassic and Early Jurassic taxa Here I report that the principal evidence for Late Triassic taxa, dermal scutes previously assigned to an aetosaur, in fact belongs to the thyreophoran ornithischian dinosaur Scelidosaurus, previously known only as a washed-in form found in marine sediments in the Early Jurassic of England. The presence of this dinosaur represents the first vertebrate biostratigraphic tie-in of the Glen Canyon Group horizons with reliably dated marine deposits in Europe. Together with revised systematic assessments of other vertebrates and independent evidence from fossil pollen, it supports an Early Jurassic age for the Kayenta Formation and most or all of the Glen Canyon Group.

  14. Permian, Jurassic and Early Cretaceous palynofloral assemblages from subsurface sedimentary rocks in Chuperbhita Coalfield, Rajmahal Basin, India.

    Science.gov (United States)

    Tripathi, A

    2001-04-01

    The results of a palynological analysis of the sedimentary sequence of Borehole RCH-151, Chuperbhita Coalfield, Rajmahal Basin, Bihar are presented here. The borehole penetrated the Rajmahal Formation (comprising two traps sandwiching an intertrappean bed), the thinly represented Dubrajpur Formation and in its lower part, the Coal Measures. The coal-bearing interval is associated with Scheuringipollenites barakarensis, Faunipollenites varius, Densipollenites indicus, Gondisporites raniganjensis and Densipollenites magnicorpus Assemblage Zones. The presence of these biostratigraphic units indicates correlation with the Barakar Formation (Early Permian) and the Barren Measures and Raniganj Formations (both Late Permian). This is the first record, in the Chuperbhita Coalfield, of Late Permian strata, which appear to represent a condensed sequence. Prior to the present study, the Permian succession was thought to have been associated entirely with the Barakar Formation. The overlying Dubrajpur Formation yielded a distinct spore-pollen assemblage (in association with the first report of dinoflagellate, Phallocysta), which is assigned to the newly identified Callialasporites turbatus palynozone of latest Early to early Middle Jurassic age. The diverse spore-pollen flora of the intertrappean bed (Rajmahal Formation) incorporates several age marker taxa, viz. Undulatisporites, Leptolepidites, Klukisporites, Ruffordiaspora, and Coptospora. The assemblages from intertrappean beds are correlated with the Ruffordiaspora australiensis palynozone of Australia. Thus the palynodating indicates Permian, latest Early to early Mid-Jurassic and Early Cretaceous age for the strata studied. This is the first record of definite Jurassic microfossils from the non-marine sequence of Rajmahal Basin, India.

  15. New dinosaur (Theropoda, stem-Averostra) from the earliest Jurassic of the La Quinta formation, Venezuelan Andes

    Science.gov (United States)

    Langer, Max C.; Rincón, Ascanio D.; Ramezani, Jahandar; Solórzano, Andrés; Rauhut, Oliver W. M.

    2014-01-01

    Dinosaur skeletal remains are almost unknown from northern South America. One of the few exceptions comes from a small outcrop in the northernmost extension of the Andes, along the western border of Venezuela, where strata of the La Quinta Formation have yielded the ornithischian Laquintasaura venezuelae and other dinosaur remains. Here, we report isolated bones (ischium and tibia) of a small new theropod, Tachiraptor admirabilis gen. et sp. nov., which differs from all previously known members of the group by an unique suite of features of its tibial articulations. Comparative/phylogenetic studies place the new form as the sister taxon to Averostra, a theropod group that is known primarily from the Middle Jurassic onwards. A new U–Pb zircon date (isotope dilution thermal-ionization mass spectrometry; ID-TIMS method) from the bone bed matrix suggests an earliest Jurassic maximum age for the La Quinta Formation. A dispersal–vicariance analysis suggests that such a stratigraphic gap is more likely to be filled by new records from north and central Pangaea than from southern areas. Indeed, our data show that the sampled summer-wet equatorial belt, which yielded the new taxon, played a pivotal role in theropod evolution across the Triassic–Jurassic boundary. PMID:26064540

  16. Apatite Fission-Track Analysis of the Middle Jurassic Todos Santos Formation from Chiapas, Mexico.

    Science.gov (United States)

    Abdullin, Fanis; Solé, Jesús; Shchepetilnikova, Valentina; Solari, Luigi; Ortega-Obregón, Carlos

    2014-05-01

    The Sierra de Chiapas (SCH), located in the south of Mexico, is a complex geological province that can be divided on four different lithological or tectonic areas: (1) the Chiapas Massif Complex (CMC); (2) the Central Depression; (3) the Strike-slip Fault Province, and (4) the Chiapas Fold-and-thrust Belt. The CMC mostly consists of Permian granitoids and meta-granitoids, and represents the basement of the SCH. During the Jurassic period red beds and salt were deposited on this territory, related to the main pulse of rifting and opening of the Gulf of Mexico. Most of the Cretaceous stratigraphy contains limestones and dolomites deposited on a marine platform setting during the postrift stage of the Gulf of Mexico rift. During the Cenozoic Era took place the major clastic sedimentation along the SCH. According the published low-temperature geochronology data (Witt et al., 2012), SCH has three main phases of thermo-tectonic history: (1) slow exhumation between 35 and 25 Ma, that affected mainly the basement (CMC) and is probably related to the migration of the Chortís block; (2) fast exhumation during the Middle-Late Miocene caused by strike-slip deformation that affects almost all Chiapas territory; (3) period of rapid cooling from 6 to 5 Ma, that affects the Chiapas Fold-and-thrust Belt, coincident with the landward migration of the Caribbean-North America plate boundaries. The two last events were the most significant on the formation of the present-day topography of the SCH. However, the stratigraphy of the SCH shows traces of the existence of earlier tectonic events. This study presents preliminary results of apatite fission-track (AFT) dating of sandstones from the Todos Santos Formation (Middle Jurassic). The analyses are performed with in situ uranium determination using LA-ICP-MS (e.g., Hasebe et al., 2004). The AFT data indicate that this Formation has suffered high-grade diagenesis (probably over 150 ºC) and the obtained cooling ages, about 70-60 Ma

  17. Identification of Calderas Associated With The Acidic Jurassic Volcanism of Southern Patagonia, Argentina

    Science.gov (United States)

    Chernicoff, C. J.; Salani, F. M.

    During the Jurassic, the Patagonian region was subject to a predominantly acidic volcanism locally known as the Chon Aike Volcanic Province, related to the breakup of Gondwana. It comprises ignimbrites, breccias and agglomerates, and a minor component of rhyolitic and dacitic lava domes. In the study area (Río Seco region, Santa Cruz Province), the Jurassic volcanics are largely overlain by Neogene and Quaternary sediments. However, the aeromagnetic survey of this region has unravelled the magnetic pattern of the volcanics, notably two conspicuous calderas, since the young cover sediments are non-magnetic. The magnetic susceptibility of the volcanic rocks ranges 50 to 80 x 10-5 S.I., as oppossed to the nearly null values of the overlying sediments. The geological interpretation of the aeromagnetic survey is mostly based on the analytic signal of the total magnetic intensity, where two distinct sub-circular magnetic lineaments have been recognized and regarded as calderic structures. The eastern caldera, 30 km wide, is centered at 48º 52' S.L./ 68º 02' W.L., and the western caldera, 23 km wide, is centered at 48º 53' S.L. / 68º 29' W.L.. In addition, a number of smaller, high gradient magnetic anomalies have been identified and interpreted as intra- and extracaldera domes. In the eastern caldera, a number of domes follow an anular pattern of fractures regarded as the boundary of an older, outer caldera. A magnetic circular lineament located within the latter structure has been interpreted as a younger, inner caldera which presents a number of small domes in its central depression; additional domes are also located in between the two calderic structures. The western caldera is less complex since it comprises a single structure with intra-caldera domes. The total magnetic gradient (analytic signal) associated with the domes is one order of magnitude higher (0.1 to 0.2) than the mean value of the region (0.03). In addition to the anular fractures and domes, a

  18. Middle Jurassic (Bajocian and Bathonian) dinosaur megatracksites, Bighorn Basin, Wyoming, USA

    Science.gov (United States)

    Kvale, E.P.; Johnson, G.D.; Mickelson, D.L.; Keller, K.; Furer, L.; Archer, A.

    2001-01-01

    Two previously unknown rare Middle Jurassic dinosaur megatracksites are reported from the Bighorn Basin of northern Wyoming in the Western Interior of the United States. These trace fossils occur in carbonate units once thought to be totally marine in origin, and constitute the two most extensive Middle Jurassic dinosaur tracksites currently known in North America. The youngest of these occurs primarily along a single horizon at or near the top of the "basal member" of the "lower" Sundance Formation, is mid-Bathonian in age, and dates to ??? 167 ma. This discovery necessitates a major change in the paleogeographic reconstructions for Wyoming for this period. The older tracksites occur at multiple horizons within a 1 m interval in the middle part of the Gypsum Spring Formation. This interval is uppermost Bajocian in age and dates to ??? 170 ma. Terrestrial tracks found, to date, have been all bipedal tridactyl dinosaur prints. At least some of these prints can be attributed to the theropods. Possible swim tracks of bipedal dinosaurs are also present in the Gypsum Spring Formation. Digitigrade prints dominate the Sundance trackways, with both plantigrade and digitigrade prints being preserved in the Gypsum Spring trackways. The Sundance track-bearing surface locally covers 7.5 square kilometers in the vicinity of Shell, Wyoming. Other tracks occur apparently on the same horizon approximately 25 kilometers to the west, north of the town of Greybull. The Gypsum Spring megatracksite is locally preserved across the same 25 kilometer east-west expanse, with the Gypsum Spring megatracksite more extensive in a north-south direction with tracks occurring locally across a 100 kilometer extent. Conservative estimates for the trackway density based on regional mapping in the Sundance tracksite discovery area near Shell suggests that over 150, 000 in situ tracks may be preserved per square kilometer in the Sundance Formation in this area. Comparable estimates have not been made

  19. Permo-Carboniferous granitoids with Jurassic high temperature metamorphism in Central Pontides, Northern Turkey

    Science.gov (United States)

    Gücer, Mehmet Ali; Arslan, Mehmet; Sherlock, Sarah; Heaman, Larry M.

    2016-12-01

    likely that peak metamorphism took place during the Jurassic as reflected by the U-Pb zircon ages (199-158 Ma) and also 40Ar/39Ar from hornblende/biotite (163-152 Ma). The four biotite 40Ar/39Ar average ages from the rock samples are ca. 156 Ma, suggesting that the metamorphic rocks cooled to 350-400 °C at ca. 156 Ma. Conclusively, the Devrekani metamorphic rocks can be ascribed as products of Permo-Carboniferous continental arc magmatism overprinted by Jurassic metamorphism in the northern Central Pontides.

  20. The earliest fossil record of Panorpidae (Mecoptera from the Middle Jurassic of China

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    He Ding

    2014-08-01

    Full Text Available The early history of Panorpidae (Mecoptera is poorly known due to sparse fossil records. Up to date, only nine fossil species have been described, all from the Paleogene, except the Early Cretaceous Solusipanorpa gibbidorsa Lin, 1980. However, we suggest S. gibbidorsa is too incompletely preserved to permit even family classification. A new genus with two new species, Jurassipanorpa impunctata gen. et sp. n. and Jurassipanorpa sticta sp. n., are described based on four well-preserved specimens from the late Middle Jurassic Jiulongshan Formation of Daohugou, Inner Mongolia, China. These two new species are the earliest fossil records of Panorpidae. The new genus is erected based on a combination of forewing characters: both R1 and Rs1 with two branches, 1A reaching posterior margin of wing distad of the forking of Rs from R1, and no crossveins or only one crossvein between veins of 1A and 2A. In all four specimens, long and robust setae ranging from 0.09 to 0.38 mm in length and pointing anteriorly, are present on anal veins of forewings. The function of these setae is enigmatic.

  1. Tunasniyoj, a dinosaur tracksite from the Jurassic-Cretaceous boundary of Bolivia.

    Science.gov (United States)

    Apesteguía, Sebastián; Gallina, Pablo A

    2011-03-01

    Here we report a superbly preserved and profusely represented five-ichnotaxa dinosaur track assemblage near Icla village, 100 km southeast of Sucre, Bolivia. As preserved in reddish Jurassic-Cretaceous boundary aeolian sandstones, this rich and uncommon assemblage is, additionally, the oldest dinosaur tracksite for Bolivia. Four trackmakers were identified in the area: three quadrupedal and one bipedal, all of them with tracks of around 35 cm in lenght. One of the quadrupedals is represented by no less than five adult individuals (ichnotaxon A), and four purported juveniles (ichnotaxon B) walking in association. The other two quadrupedals (ichnotaxa C and D) involve four trackways, and the last, the bipedal trackmaker (ichnotaxon E), is represented by one trackway. The five ichnotaxa represented in the "Palmar de Tunasniyoj" could be tentatively assigned to the following trackmakers: Ichnotaxa A and B are assigned to basal stegosaurians; ichnotaxon C to a basal tyreophoran, perhaps related to the ankylosaur lineage; ichnotaxon D to the Ankylosauria, and ichnotaxon E to Theropoda. The Tunasniyoj assemblage, the oldest dinosaur tracksite for Bolivia, includes the oldest known evidence assigned to ankylosaurs and stegosaurs for South America.

  2. Vertebral pathology in an ornithopod dinosaur: a hemivertebra in Dysalotosaurus lettowvorbecki from the Jurassic of Tanzania.

    Science