WorldWideScience

Sample records for southwestern massif central

  1. The geology of uranium in the Saint-Sylvestre granite district (Limousin, Massif Central, France); La geologie de l'uranium dans le massif granitique de Saint-Sylvestre (Limousin - Massif Central Francais)

    Energy Technology Data Exchange (ETDEWEB)

    Marquaire, C; Moreau, M; Barbier, J; Ranchin, G; Carrat, H G; Coppens, R; Senecal, J; Koszotolanyi, C; Dottin, H

    1969-07-01

    This report concerns the geology of uranium in Limousin, more particularly in the St-Sylvestre massif, and the related phenomena: regional geology, petrographic and geochemical zonal distribution observed in various granite massifs, uranium movement in connection with surface alteration, geochronology of uranium ore. The work is made up of six articles covering the various scientific aspects listed above. Each article is headed with an abstract. The paper comprises the following chapters: Foreword by Marcel ROUBAULT. 1. Ch. MARQUAIRE, M. MOREAU Outline of geological conditions in Northern Limousin and distribution of uraniferous occurrences. 2. J. BARBIER, G. RANCHIN, H. G. CARRAT and R. COPPENS Geology of the St-Sylvestre Massif and uranium geochemistry - Introduction to laboratory studies - Problems of methodology. 3. J. BARBIER and G. RANCHIN Petrographical and geochemical zones in the St-Sylvestre granite massif (Limousin - French 'Massif Central'). 4. J. BARBIER and G. RANCHIN Uranium geochemistry in the St-Sylvestre Massif (Limousin - French 'Massif Central') - Occurrences of primary geochemical uranium and replacement processes. 5. J. SENEGAL Monograph of the Brugeaud orebody. 6. R. COPPENS, Ch. KOSZTOLANYI and H. DOTTIN Geochronological study of the Brugeaud mine. 1969. (authors) [French] Ce memoire est consacre a la geologie de l'uranium dans le Limousin, plus specialement dans le massif de St-Sylvestre, et aux phenomenes qui s'y rattachent: geologie regionale, phenomenes de zonalite petrographique et geochimique dans certains massifs granitiques, mouvements de l'uranium lies a l'alteration superficielle, geochronologie du minerai d'uranium. L'ouvrage comprend six articles qui recouvrent les differents aspects scientifiques enumeres. Chacun de ces six articles est precede d'un resume. La composition du memoire st la suivante: Marcel ROUBAULT, Preface. 1. Ch. MARQUAIRE, M. MOREAU Esquisse geologique du Nord Limousin et repartition des mineralisations

  2. The geology of uranium in the Saint-Sylvestre granite district (Limousin, Massif Central, France); La geologie de l'uranium dans le massif granitique de Saint-Sylvestre (Limousin - Massif Central Francais)

    Energy Technology Data Exchange (ETDEWEB)

    Marquaire, C.; Moreau, M.; Barbier, J.; Ranchin, G.; Carrat, H.G.; Coppens, R.; Senecal, J.; Koszotolanyi, C.; Dottin, H

    1969-07-01

    This report concerns the geology of uranium in Limousin, more particularly in the St-Sylvestre massif, and the related phenomena: regional geology, petrographic and geochemical zonal distribution observed in various granite massifs, uranium movement in connection with surface alteration, geochronology of uranium ore. The work is made up of six articles covering the various scientific aspects listed above. Each article is headed with an abstract. The paper comprises the following chapters: Foreword by Marcel ROUBAULT. 1. Ch. MARQUAIRE, M. MOREAU Outline of geological conditions in Northern Limousin and distribution of uraniferous occurrences. 2. J. BARBIER, G. RANCHIN, H. G. CARRAT and R. COPPENS Geology of the St-Sylvestre Massif and uranium geochemistry - Introduction to laboratory studies - Problems of methodology. 3. J. BARBIER and G. RANCHIN Petrographical and geochemical zones in the St-Sylvestre granite massif (Limousin - French 'Massif Central'). 4. J. BARBIER and G. RANCHIN Uranium geochemistry in the St-Sylvestre Massif (Limousin - French 'Massif Central') - Occurrences of primary geochemical uranium and replacement processes. 5. J. SENEGAL Monograph of the Brugeaud orebody. 6. R. COPPENS, Ch. KOSZTOLANYI and H. DOTTIN Geochronological study of the Brugeaud mine. 1969. (authors) [French] Ce memoire est consacre a la geologie de l'uranium dans le Limousin, plus specialement dans le massif de St-Sylvestre, et aux phenomenes qui s'y rattachent: geologie regionale, phenomenes de zonalite petrographique et geochimique dans certains massifs granitiques, mouvements de l'uranium lies a l'alteration superficielle, geochronologie du minerai d'uranium. L'ouvrage comprend six articles qui recouvrent les differents aspects scientifiques enumeres. Chacun de ces six articles est precede d'un resume. La composition du memoire st la suivante: Marcel ROUBAULT, Preface. 1. Ch. MARQUAIRE, M. MOREAU Esquisse geologique du

  3. The geology of uranium in the Saint-Sylvestre granite district (Limousin, Massif Central, France)

    International Nuclear Information System (INIS)

    Marquaire, C.; Moreau, M.; Barbier, J.; Ranchin, G.; Carrat, H.G.; Coppens, R.; Senecal, J.; Koszotolanyi, C.; Dottin, H.

    1969-01-01

    This report concerns the geology of uranium in Limousin, more particularly in the St-Sylvestre massif, and the related phenomena: regional geology, petrographic and geochemical zonal distribution observed in various granite massifs, uranium movement in connection with surface alteration, geochronology of uranium ore. The work is made up of six articles covering the various scientific aspects listed above. Each article is headed with an abstract. The paper comprises the following chapters: Foreword by Marcel ROUBAULT. 1. Ch. MARQUAIRE, M. MOREAU Outline of geological conditions in Northern Limousin and distribution of uraniferous occurrences. 2. J. BARBIER, G. RANCHIN, H. G. CARRAT and R. COPPENS Geology of the St-Sylvestre Massif and uranium geochemistry - Introduction to laboratory studies - Problems of methodology. 3. J. BARBIER and G. RANCHIN Petrographical and geochemical zones in the St-Sylvestre granite massif (Limousin - French 'Massif Central'). 4. J. BARBIER and G. RANCHIN Uranium geochemistry in the St-Sylvestre Massif (Limousin - French 'Massif Central') - Occurrences of primary geochemical uranium and replacement processes. 5. J. SENEGAL Monograph of the Brugeaud orebody. 6. R. COPPENS, Ch. KOSZTOLANYI and H. DOTTIN Geochronological study of the Brugeaud mine. 1969. (authors) [fr

  4. Les Gammaridae (Crustaces, Amphipodes) du Massif Central

    NARCIS (Netherlands)

    Goedmakers, Annemarie

    1974-01-01

    Une prospection systématique des eaux courantes du Massif Central a permis de reconnaître le nombre d’espèces des Gammaridés présentes dans cette région. On a trouvé les espèces suivantes: Gammarus pulex (Linnaeus, 1758), G. fossarum Koch, 1835, et G. ibericus Margalef, 1951. G. ibericus, espèce

  5. Defining conditions of garnet growth across the central and southern Menderes Massif, western Turkey

    Science.gov (United States)

    Etzel, T. M.; Catlos, E. J.; Kelly, E. D.; Cemen, I.; Ozerdem, C.; Atakturk, K. R.

    2017-12-01

    Here we apply thermodynamic modeling using Theriak-Domino to garnet-bearing rocks from the central and southern portions of the Menderes Massif to gain insight into the dynamics of western Turkey as the region experienced a transition from collisional to extensional tectonics. To this end, we report new pressure-temperature (P-T) paths from garnet-bearing rocks collected along the Alasehir detachment fault, a prominent exhumation structure in the central portion of the Menderes Massif in western Turkey, constituting the southern margin of the Alasehir Graben. These paths are compared to those from the Selimiye shear zone in the Southern (Cine) Massif. Two Alasehir garnets collected from the same outcrop record two P-T paths: 1) a prograde path beginning at 565oC and 6.4 kbar increasing to 592 oC and 7.5 kbar; and 2) near isobaric growth initiating at 531oC and 7.1 kbar and terminating at 571oC and 7.3 kbar. High-resolution P-T paths could not be modeled for the majority of Alasehir samples due to diffusional modification of garnet. However, conditions were estimated by garnet isopleth thermobarometry at the point of highest spessartine content for each crystal. Calculated P-T values for this subset of samples range between 566-651oC and 6.2-6.8 kbar. Despite this broad range, these P-T conditions are consistent with what is observed in the modeled paths. Th-Pb ages of matrix monazite range from 35.8±3.0 to 20.6±2.4 Ma, suggesting metamorphism in the central Menderes Massif occurred over a 15 m.y. period. Selimiye shear zone rocks show distinct N-shaped P-T paths, suggesting garnets in the central and southern portion of the Menderes Massif record distinctly different tectonic histories.

  6. Grass survey of the Itremo Massif records endemic central highland ...

    African Journals Online (AJOL)

    Twenty species are endemic to the central highlands, and a further 1 4 species are restricted to Madagascar. Five ecological groups of grasses were identified in the Itremo Massif: shade species in gallery forests, open wet area species, fire grasses, anthropogenic disturbance associated grasses and rock-dwelling grasses.

  7. Continental basinal origin of ore fluids from southwestern Massif central fluorite veins (Albigeois, France): evidence from fluid inclusion and stable isotope analyses

    International Nuclear Information System (INIS)

    Munoz, M.; Boyce, A.J.; Courjault-Rade, P.; Fallick, A.E.; Tollon, F.

    1999-01-01

    The most important fluorspar mining district in France is located in the Palaeozoic basement of the Albigeois in southwestern French Massif Central. The massive fluorite is hosted within large E-W striking fractures, crosscutting Cambro-Ordovician clastics, associated with large zones of hypersilicified tectonic breccia which form the wall of the mined deposits. Fluid inclusion data for pre-fluorite and fluorite stage fluids have salinities between 20-26 wt% NaCl equiv., with homogenisation temperatures between 85-170C. Furthermore, low first ice melting temperatures (around -50C) indicates the presence of significant CaCl 2 and possibly MgCl 2 together with NaCl. Calculated fluid δ 18 O for pre-fluorite quartz ranges from -9.1per thousand to -5.2per thousand, with δD between -55per thousand to -64per thousand, placing the data directly on the present day meteoric water line. Fluorite stage fluids have δ 18 O between +0.1per thousand to +3.2per thousand, and δD ranging from -53per thousand to -75per thousand, indicating an interacted meteoric fluid origin. Combining the fluid inclusion and stable isotope data illustrates that the main fluorite depositing fluid has characteristics typical of a basinal brine. The authors have no evidence that a magmatic system was involved in the deposit genesis. The proposed model highlights that mineralisation was related to major Mesozoic extensional events coinciding with the gradual opening of the Atlantic and Tethys oceans. In order to account for the chemistry of the fluids, and the siting of the deposits, the authors postulate a genetic relationship with local, continental, evaporite-bearing basins coincident with, and controlled by the E-W fractures. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  8. Extensional ductile tectonics of the Sioule metamorphic series (Variscan French Massif Central)

    Science.gov (United States)

    Faure, M.; Grolier, J.; Pons, J.

    1993-09-01

    In the Northern part of the Variscan French Massif Central, the Sioule series, from top to bottom, consists of a pre-Viséan granite, migmatite, gneiss and mica schist. Two ductile deformations have been recognized. The earlier phase is characterized by a north-east-south-west trending stretching lineation; the second phase, characterized by a north-west-south-east trending mineral, stretching and crenulation lineation, is better marked in the lower mica schist part than in the upper granito-gneissic part. This second phase occurred during retrogression of the metamorphic rocks; related shear criteria indicate a top to the south-west shear. The Namurian-Westphalian magmatic bodies such as the Echassières leucogranite, Pouzol-Servant microgranite and numerous north-east -south-west trending microgranite dykes are emplaced in extensional fractures related to the same north-west-south-east maximum stretching direction. The asymmetrical shapes of the two granitic massifs indicate that they intruded towards the south-east. The synkinematic retrogression of the metamorphic rocks, the shape of the magmatic bodies and a re-examination of the numerous available data support the interpretation that the deformation is due to the extensional tectonic regime related to the Variscan crustal re-quilibration. This interpretation is in agreement with the correlation of the Sioule series with the Chavanon series. The two series belong to a unique tectono-metamorphic unit left-laterally offset by the Stephanian motion of the Sillon Houiller fault. This study also shows that the Sillon Houiller did not play a significant part during the Namurian-Westphalian extensional tectonics of the Massif Central.

  9. A-type granites from the Guéra Massif, Central Chad: Petrology, geochemistry, geochronology, and petrogenesis.

    Science.gov (United States)

    Pham, Ngoc Ha T.; Shellnutt, J. Gregory; Yeh, Meng-Wan; Lee, Tung-Yi

    2017-04-01

    The poorly studied Saharan Metacraton of North-Central Africa is located between the Arabian-Nubian Shield in the east, the Tuareg Shield in the west and the Central African Orogenic Belt in the south. The Saharan Metacraton is composed of Neoproterozoic juvenile crust and the relics of pre-Neoproterozoic components reactivated during the Pan-African Orogeny. The Republic of Chad, constrained within the Saharan Metacraton, comprises a Phanerozoic cover overlying Precambrian basement outcroppings in four distinct massifs: the Mayo Kebbi, Tibesti, Ouaddaï, and the Guéra. The Guéra massif is the least studied of the four massifs but it likely preserves structures that were formed during the collision between Congo Craton and Saharan Metacraton. The Guéra Massif is composed of mostly granitic rocks. The granitoids have petrologic features that are consistent with A-type granite, such as micrographic intergrowth of sodic and potassic feldspar, the presence of sodic- and iron-rich amphibole, and iron-rich biotite. Compositionally, the granitic rocks of the Guéra Massif have high silica (SiO2 ≥ 68.9 wt.%) content and are metaluminous to marginally peraluminous. The rocks are classified as ferroan calc-alkalic to alkali-calcic with moderately high to very high Fe* ratios. The first zircon U/Pb geochronology of the silicic rocks from the Guéra Massif yielded three main age groups: 590 Ma, 570 Ma, 560 Ma, while a single gabbro yielded an intermediate age ( 580 Ma). A weakly foliated biotite granite yielded two populations, in which the emplacement age is interpreted to be 590 ± 10 Ma, whereas the younger age (550 ± 11 Ma) is considered to be a deformation age. Furthermore, inherited Meso- to Paleoproterozoic zircons are found in this sample. The geochemical and geochronology data indicate that there is a temporal evolution in the composition of rocks with the old, high Mg# granitoids shifting to young, low Mg# granitoids. This reveals that the A-type granites in

  10. Geology and uranium occurrences in the Forez tertiary plain (in the French 'Massif Central'); Geologie et mineralisations uraniferes de la plaine tertiaire du Forez (Massif Central francais)

    Energy Technology Data Exchange (ETDEWEB)

    Duclos, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses - 92 (France). Centre d' Etudes Nucleaires

    1967-01-01

    In the first part, the observations made during the geological survey of the Forez Tertiary plain (in the French 'Massif Central') are recalled. Then, using various methods, the author lists the formations according to chronology. Finally, a reconstitution of the geological history of this subsidence basin is attempted. In the second part, the occurrence of 17 uranium bearing geochemical anomalies is commented upon. Each of these various anomalies is given a place on the stratigraphic scale. This enables the author to put the successive phases of uranium deposition into their proper perspective in the history of the plain. In conclusion, the author points out the usefulness of these uraniferous geochemical anomalies. (author) [French] Dans la premiere partie, l'auteur rappelle les observations faites au cours de l'etude geologique de la plaine tertiaire du Forez (Massif Central francais). Puis se servant de differentes methodes, il etablit une chronologie des formations. Enfin, il termine par un essai de reconstitution de l'histoire geologique de ce bassin de subsidence. Dans la deuxieme partie, il commente la decouverte de 17 anomalies geochimiques uraniferes. Il situe ces differentes anomalies dans la serie stratigraphique. Ceci lui permet de replacer les depots successifs de l'uranium dans l'histoire de la plaine. Enfin, il indique l'interet de ces anomalies geochimiques uraniferes. (auteur)

  11. Geology and uranium occurrences in the Forez tertiary plain (in the French 'Massif Central'); Geologie et mineralisations uraniferes de la plaine tertiaire du Forez (Massif Central francais)

    Energy Technology Data Exchange (ETDEWEB)

    Duclos, P. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses - 92 (France). Centre d' Etudes Nucleaires

    1967-01-01

    In the first part, the observations made during the geological survey of the Forez Tertiary plain (in the French 'Massif Central') are recalled. Then, using various methods, the author lists the formations according to chronology. Finally, a reconstitution of the geological history of this subsidence basin is attempted. In the second part, the occurrence of 17 uranium bearing geochemical anomalies is commented upon. Each of these various anomalies is given a place on the stratigraphic scale. This enables the author to put the successive phases of uranium deposition into their proper perspective in the history of the plain. In conclusion, the author points out the usefulness of these uraniferous geochemical anomalies. (author) [French] Dans la premiere partie, l'auteur rappelle les observations faites au cours de l'etude geologique de la plaine tertiaire du Forez (Massif Central francais). Puis se servant de differentes methodes, il etablit une chronologie des formations. Enfin, il termine par un essai de reconstitution de l'histoire geologique de ce bassin de subsidence. Dans la deuxieme partie, il commente la decouverte de 17 anomalies geochimiques uraniferes. Il situe ces differentes anomalies dans la serie stratigraphique. Ceci lui permet de replacer les depots successifs de l'uranium dans l'histoire de la plaine. Enfin, il indique l'interet de ces anomalies geochimiques uraniferes. (auteur)

  12. New Paleomagnetic Data From Upper Gabbros Supports Limited Rotation of Central Semail Massif in Oman Ophiolite

    Science.gov (United States)

    Horst, A. J.; Sarah, T.; Hartley, E.; Martin, J.

    2017-12-01

    Paleomagnetic data from northern massifs of the Oman ophiolite demonstrate substantial clockwise rotations prior to or during obduction, yet data from southern massifs are recently suggested to be remagnetized during obduction and show subsequent smaller counterclockwise rotations. To better understand paleomagnetic data from the southern massifs, we conducted a detailed paleomagnetic and rock magnetic study of 21 sites in upper gabbros and 5 sites in lower crustal gabbros within the central Semail massif. Samples treated with progressive thermal demagnetization yield interpretable magnetizations with dominant unblocking between 500-580°C that implies characteristic remanent magnetization (ChRM) components carried by low-titanium magnetite and nearly pure magnetite. Rock magnetic and scanning electron microscopy data provide additional support of the carriers of magnetization. ChRMs from sites with samples containing partially-serpentinized olivine are similar to sites with samples lacking olivine, where the carriers appear to be fine magnetite intergrowths in pyroxene. The overall in situ and tilt-corrected mean directions from upper gabbros are distinct from the lower gabbros, from previous data within the massif, and also directions from similar crustal units in adjacent Rustaq and Wadi Tayin massifs. After tilt correction for 10-15° SE dip of the crust-mantle boundary, the mean direction from upper gabbros is nearly coincident with in situ lower gabbros. The tilt-corrected direction from upper gabbros is also consistent with an expected direction from the Late Cretaceous apparent polar wander path for Arabia at the age of crustal accretion ( 95Ma). These results suggest the upper crustal section in Semail has likely only experienced minor tilting since formation and acquisition of magnetization. Due to slow cooling of middle to lower gabbros in fast-spread crust, the lower gabbro sites likely cooled later or after obduction, and thus yield a distinct

  13. A contribution of airborne magnetic, gamma ray spectrometric data in understanding the structure of the Central Jebilet Hercynian massif and implications for mining

    Science.gov (United States)

    Maacha, Lhou; Jaffal, Mohammed; Jarni, Abdelmajid; Kchikach, Azzouz; Mouguina, El Mostafa; Zouhair, Mohamed; Ennaciri, Aomar; Saddiqi, Omar

    2017-10-01

    The Central Jebilet massif, well-known for its mining potential, has been explored for several years by the Managem Group, in collaboration with the National Office of Hydrocarbons and Mines (ONHYM), Morocco. This massif was surveyed by high-resolution magnetic and gamma-ray spectrometric methods in 1997 as part of a broader exploration program. In order to better exploit the results of this survey in understanding the structure of the Central Jebilet massif, we performed a series of processing of the collected data. The qualitative interpretation of this data highlighted the various magnetic domains, structures (e.g., lineaments and faults), and mafic intrusions. Euler deconvolution calculations provided estimates of the spatial location and depth of the magnetic sources, and spectral analysis of the magnetic data allowed further refinement of these depth estimates. Quantitative interpretation of some anomalies associated with exposed gossans allowed the characterization of their causative bodies, inferred to be sulfide deposits. The magnetic character of both the potential massive-sulfide bodies and the basic magmatic rocks (gabbro) were determined by the aeromagnetic data. Gamma ray spectrometric data has helped facilitate lithological discrimination and alteration zones, based on the radio-elemental distribution in the area. For example, the Thorium to Potassium ratio (Th/K) was used to highlight potassic alteration zones associated with massive-sulfide deposits in the Central Jebilet. The combined magnetic and radiometric study reveals the magnetic character of the Central Jebilet gossans, due to the content of pyrrhotite, which along with potassic alterations, has been recognized in all the known deposits of the Marrakech region. The results of this geophysical campaign supplement the existing geological and structural maps of Central Jebilet massif.

  14. Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians

    Science.gov (United States)

    Bąk, Krzysztof; Bąk, Marta

    2013-06-01

    Bąk, K. and Bąk M. 2013. Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians. Acta Geologica Polonica, 63 (2), 223-237. Warszawa. The foraminiferal and radiolarian biostratigraphy of selected sections of the Zabijak Formation, the youngest sediments of the Tatra massif (Central Western Carpathians), have been studied. Benthic foraminifers, mainly agglutinated species, occur abundantly and continuously throughout the studied succession, while planktic foraminifers are generally sparse. Five planktic and two benthic foraminiferal zones have been recognized. The marly part of the Zabijak Formation comprises the Pseudothalmanninella ticinensis (Upper Albian) through the Rotalipora cushmani (Upper Cenomanian) planktic foraminiferal zones, and the Haplophragmoides nonioninoides and Bulbobaculites problematicus benthic foraminiferal zones. The radiolarians were recognized exclusively in the Lower Cenomanian part of the formation.

  15. Occurrence of an unknown Atlantic eruption in the Chaîne des Puys volcanic field (Massif Central, France)

    Science.gov (United States)

    Jouannic, G.; Walter-Simonnet, A. V.; Bossuet, G.; Cubizolle, H.; Boivin, P.; Devidal, J. L.; Oberlin, C.

    2014-08-01

    A volcanic ash layer, called MF1, was recently identified in Holocene sediments from the Gourgon and Molhiac peat bogs (Monts du Forez, French Massif Central). This ash layer consists of colorless shards with a heterogeneous trachytic to rhyolitic composition. The trace elements analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) attest to a local origin. Radiocarbon dating of peat samples taken within and below the ash layer indicates the best age at 6339 ± 61 cal yr BP, i.e. an age contemporaneous with the volcanic activity of Montchal, Montcineyre and Pavin volcanoes from the Chaîne des Puys volcanic field. These volcanoes are characterized by basaltic and trachytic products, thus the rhyolitic composition of MF1 tephra suggests that it is likely originated from an unknown eruption. These results again confirm the interest of studying the distal volcanic ash fallouts in order to establish or specify records of past eruptions of volcanic fields. Identification of this new tephra layer also provides an additional tephrochronological marker for Eastern French Massif Central.

  16. Late Cenozoic cooling history of the central Menderes Massif and the contribution of erosion to rock exhumation during active continental extension

    Science.gov (United States)

    Nilius, Nils-Peter; Wölfler, Andreas; Heineke, Caroline; Glotzbach, Christoph; Hetzel, Ralf; Hampel, Andrea; Akal, Cüneyt; Dunkl, István

    2017-04-01

    The Menderes Massif constitutes the western part of the Anatolide belt in western Turkey and experienced a prolonged history of post-orogenic extension. A large amount of the extension was accommodated by the two oppositely dipping Gediz and Büyük Menderes detachment faults, which led to the exhumation of the central Menderes Massif (Gessner et al., 2013). Previous studies proposed a synchronous, bivergent exhumation of the central Menderes Massif since the Miocene (Gessner et al., 2001), although only the evolution of the north-dipping Gediz detachment is well constrained (Buscher et al., 2013). Detailed structural and thermochronological investigations from the south-dipping Büyük Menderes detachment have still been missing. Here we present results from different thermochronometers, which constrain the cooling and exhumation history of footwall and hanging wall rocks of the Büyük Menderes detachment. Our new zircon and apatite (U-Th)/He and fission track ages of footwall rocks from the Büyük Menderes detachment document two phases of increased cooling and exhumation (Wölfler et al., in revision). The first episode of increased footwall exhumation ( 0.9 km/Myr) occurred during the middle Miocene, followed by a second phase during latest Miocene and Pliocene ( 1.0 km/Myr). Apatite fission track ages yield a slip rate for the Pliocene movement along the Büyük Menderes detachment of 3.0 (+1.1/-0.6) km/Myr. Thermochronological data of hanging wall units reflect a slow phase of exhumation ( 0.2 km/Myr) in the late Oligocene and an increased exhumation rate of 1.0 km/Myr during the early to middle Miocene, when hanging wall units cooled below 80 °C. In comparison with the Gediz detachment, our thermochronological data from the Büyük Menderes detachment confirms the concurrent activity of both detachments during the late Miocene and Pliocene. With respect to the relative importance of normal faulting and erosion to rock exhumation, a comparison with 10Be

  17. Gammarus orinos n. sp. from the Massif Central (France): its genetic and morphological distinction from Gammarus ibericus Margalef, 1951 (Crustacea, Amphipoda)

    NARCIS (Netherlands)

    Pinkster, Sjouk; Scholl, Adolf

    1984-01-01

    Until 1974 Gammarus ibericus was known only from the type-locality in Spain. In that year, Goedmakers recorded the species from many localities in the Massif Central, France. Indeed, these populations show a great morphological resemblance to the Spanish ones. These French populations were used in

  18. Late Hercynian volcanic and hypovolcanic phenomena in South of the French Massif Central. Associated mineralization: U, F, Ba, Pb, Zn, Sn, W

    International Nuclear Information System (INIS)

    Badia; Fuchs

    1983-01-01

    Volcanism of the Stephanian period produced lava rich in potassium and fluorine with mineralization of U, F, Sn, W without Mo in the French Massif Central. Permian volcanism and associated magmatism are reviewed. Studied elements allow the characterization of their thermalism. These mineralizations are important for prospection [fr

  19. Geology and uranium occurrences in the Forez tertiary plain (in the French 'Massif Central')

    International Nuclear Information System (INIS)

    Duclos, P.

    1967-01-01

    In the first part, the observations made during the geological survey of the Forez Tertiary plain (in the French 'Massif Central') are recalled. Then, using various methods, the author lists the formations according to chronology. Finally, a reconstitution of the geological history of this subsidence basin is attempted. In the second part, the occurrence of 17 uranium bearing geochemical anomalies is commented upon. Each of these various anomalies is given a place on the stratigraphic scale. This enables the author to put the successive phases of uranium deposition into their proper perspective in the history of the plain. In conclusion, the author points out the usefulness of these uraniferous geochemical anomalies. (author) [fr

  20. Timing and duration of Variscan high-pressure metamorphism in the French Massif Central: A multimethod geochronological study from the Najac Massif

    Science.gov (United States)

    Lotout, Caroline; Pitra, Pavel; Poujol, Marc; Anczkiewicz, Robert; Van Den Driessche, Jean

    2018-05-01

    Accurate dating of eclogite-facies metamorphism is of paramount importance in order to understand the tectonic evolution of an orogen. An eclogite sample from the Najac Massif (French Massif Central, Variscan belt) displays a zircon-bearing garnet-omphacite-amphibole-rutile-quartz peak assemblage. Pseudosection modeling suggests peak pressure conditions of 15-20 kbar, 560-630 °C. Eclogite-facies garnet displays Lu-enriched cores and Sm-rich rims and yields a Lu-Hf age of 382.8 ± 1.0 Ma and a Sm-Nd age of 376.7 ± 3.3 Ma. The ages are interpreted as marking the beginning of the prograde garnet growth during the initial stages of the eclogite-facies metamorphism, and the high-pressure (and temperature) peak reached by the rock, respectively. Zircon grains display chondrite-normalized REE spectra with variably negative, positive or no Eu anomalies and are characterized by either enriched or flat HREE patterns. However, they yield a well constrained in situ LA-ICP-MS U-Pb age of 385.5 ± 2.3 Ma, despite this REE pattern variability. Zr zonation in garnet, Y content in zircon and the diversity of zircon HREE spectra may suggest that zircon crystallized prior to and during incipient garnet growth on the prograde P-T path, recording the initial stages of the eclogite-facies conditions. Consequently, the zircon age of 385.5 ± 2.3 Ma, comparable within error with the Lu-Hf age obtained on garnet, is interpreted as dating the beginning of the eclogite-facies metamorphism. Accordingly, the duration of the prograde part of the eclogite-facies event is estimated at 6.1 ± 4.3 Myr. Subsequent exhumation is constrained by an apatite U-Pb age at 369 ± 13 Ma.

  1. Heat flow map of the Bohemian massif

    Energy Technology Data Exchange (ETDEWEB)

    Cermak, V [Geophys. Inst., CS Acad. of Sci.

    1977-01-01

    Forty seven heat flow values for the Bohemian massif were used to determine the heat flow pattern of the area. By including data from neighboring countries it was possible to draw an isothermal map outlining the geothermal activity. As a result, it is possible to closely correlate the heat flow and the tectonic structure. It is obvious that the areas of high geothermal activity correspond to zones of crustal weakness associated with two major faults bordering the rigid central section of the massif. The highest heat flow values coincide with the axis of the sedimentary basin. The development of these heat flow patterns should assist in the recognition of probable areas of geothermal resources and several promising sites are readily discernible.

  2. Seismic anisotropy of the French Massif Central and predisposition of Cenozoic rifting and volcanism by Variscan suture hidden in the mantle lithosphere

    Czech Academy of Sciences Publication Activity Database

    Babuška, Vladislav; Plomerová, Jaroslava; Vecsey, Luděk; Granet, M.; Achauer, U.

    2002-01-01

    Roč. 21, č. 4 (2002), s. U407-U429 ISSN 0278-7407 R&D Projects: GA ČR GV205/98/K004; GA ČR GA205/01/1154; GA AV ČR IAA3012908 Institutional research plan: CEZ:AV0Z3012916 Keywords : seismic anisotropy * Massif Central * mantle lithosphere Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.697, year: 2002

  3. A NEW INTERPRETATION FOR THE GARNET ZONING IN METAPELITIC ROCKS OF THE SILGARÁ FORMATION, SOUTHWESTERN SANTANDER MASSIF, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Ríos Reyes Carlos Alberto

    2008-06-01

    Full Text Available A Barrovian sequence of the Silgará Formation at the southwestern Santander Massif, Colombian Andes, contains zoned garnets in which major and trace element zoning correlates with distribution of mineral inclusions, which may indicate that garnet growth rate varied through time and affected both composition and texture ofgarnets, although different garnet producing reactions have also played an important role in the chemical zoning of garent. However, a local metasomatism process associated to the action of late magmatic fluids associated to the emplacement of the Pescadero Pluton (external forcing mechanism would be also considered. In particular, Ca, Mn and Y zoning patterns in some garnets correspond with inclusion-rich vs. inclusion-free zones, althoughthe distribution of inclusions does not correlate with chemical zoning (i.e., the same inclusions are found in Ca-rich and Ca-poor zones of the garnet. There is a similar lack of correlation with accessory phases (apatite, monazite, xenotime, ilmenite or rutile. In a garnet from the garnet-staurolite zone, a high Mn core containsabundant and randomly oriented apatite, monazite and ilmenite inclusions, while a euhedral low Ca mantle zone is inclusion-free and the high Ca / low Mn rim zone contains apatite, monazite and ilmenite aligned parallel to the margins of the garnet. Inclusions in garnet can also represent mineral phases were not completely consumed during garnet growth. Association of garnet zoning trends and patterns with inclusion distribution may help differentiatebetween processes that identically affect major-element zoning but that produced variable textures in the garnet.

  4. Petrology and geochemistry of primary magmas trapped in melt inclusions in scoria of Beaunit Maar (Chaîne des Puys, Massif Central, France)

    Science.gov (United States)

    Jannot, S.; Schiano, P.; Boivin, P.; Clocchiatti, R.; Chazot, G.

    2003-04-01

    The Massif Central area, characterized by a typical intraplate alkaline serie, is the largest magmatic province of the West-European Rift system. Although it has been the subject of several studies, the nature of Massif Central sources is still a matter of debate and many hypotheses are proposed, including deep-rooted continental hotspot, metasomatised spinel lherzolites and an asthenospheric flow linked to the lithospheric root of the Alpine chain. The Chaîne des Puys is the last magmatic province of the French Massif Central and is composed of hundred young well-preserved volcanoes. The present work aims to supply information on the nature and the origin of the source chemistry of alkaline serie from the Chaîne des Puys, by characterizing the trace and major element composition of minute melts preserved as quenched glass inclusions inside olivines phenocrysts in scoria from the Beaunit Maar. Heating stage experiments performed at ambient pressure on partially crystallised primary melt inclusions suggest CO_2 oversaturation of the trapped melt, and an entrapment temperature around 1200^oC±10^oC. Daughter minerals analyses point to a Ti-and Ca-rich basaltic paragenesis, in good agreement with that of erupted basalts from the Chaîne des Puys. Major element compositions show that melts trapped in inclusions evolve by limited fractional crystallization. Inclusions trapped in the more primitive olivine phenocrysts (Fo85) have alkali-basalt compositions that fall on the primitive end of the compositional trend define by the lavas of the Chaîne des Puys. Their major element chemistry rules out the hypothesis of a mantle source in the spinel stability field and requires a garnet-bearing mantle source. Analyzed for trace-element composition by LA-ICP-MS, they display homogeneous, enriched patterns, similar to those characterizing oceanic island and continental basalts. They have high concentration of LILE and LREE/HREE ratios. Such trace-element feature are typical of

  5. 222Rn activity concentration differences in groundwaters of three Variscan granitoid massifs in the Sudetes (NE Bohemian Massif, SW Poland)

    International Nuclear Information System (INIS)

    Przylibski, Tadeusz A.; Gorecka, Joanna

    2014-01-01

    Based on research conducted in three Variscan granitoid massifs located within the crystalline Bohemian Massif, the authors confirmed that the higher the degree of their erosional dissection, the smaller the concentration of 222 Rn in groundwaters circulating in these massifs. This notion implies that radon waters and high-radon waters, from which at least some of the dissolved radon should be removed before feeding them as drinking water to the water-supply system, could be expected in granitoid massifs which have been poorly exposed by erosion. At the same time, such massifs must be taken into account as the areas of possible occurrence of radon medicinal waters, which in some countries can be used for balneotherapy in health resorts. Slightly eroded granitoid massifs should be also regarded as very probable radon prone areas or areas of high radon potential. - Highlights: • The concentration of 222 Rn in groundwater depends on the zone of the granitoid massif which is exposed on the ground surface. • The highest 222 Rn concentrations occur in the least eroded granitoid massifs, the lowest in massifs with exposed root parts. • The stronger the erosional dissection of a granitoid massif, the lower 222 Rn concentration in groundwaters in this massif. • Not all granitoid massifs are areas with groundwaters containing high concentrations of 222 Rn. • The least eroded granitoid massifs are radon prone areas with the occurrence of high-radon and radon groundwaters

  6. Variations in Tectonic Activities of the Central and Southwestern Foothills, Taiwan, Inferred from River Hack Profiles

    Directory of Open Access Journals (Sweden)

    Yen-Chieh Chen

    2006-01-01

    Full Text Available A longitudinal profile of a river under static equilibrium shows no degradation or aggradation and can be ideally described as a straight line on a semi-logarithmic graph. This type of profile is called a “Hack profile”. If a river runs across uprising active structure systems, its Hack profile becomes convex. Accumulated tectonic strain varies positively with the intensity of the upwarping in Hack-profile convexity. In this paper, we compare curvature changes in Hack profiles of a series of rivers running through faults in the central and southwestern Foothills of Taiwan. Longitudinal profiles of these rivers were derived from two versions of topographic maps (1904 and 1985 and recent DTM data (2000. Prior to comparisons, we calibrated the 1904 topographic map, named “Taiwan Bautu”, by “offsetting” horizontal coordinates north and westward approximately 440 m and then “linear transforming” the elevation values. The Tungtzchiau fault of the central Foothills has remained inactive since 1935. Here relatively high uplift activity near the Wu River is indicated by significantly convex Hack profiles. This strain accumulation can be attributed to a lack of small magnitude earthquakes along the fault over the past 70 years. In the southwestern Foothills, relatively high uplift activity of similar intensity to the central Foothills is indicted near the Neocho River. Significant profiles with concave segments below the ideal graded profiles, at the lower reaches of rivers where continuous small magnitude strain release events have occurred, can only be found along the Sandieh, Neocho and Bazhang rivers in the southwestern Foothills. All these findings indicate that fault systems in the central Foothills tend to be locked and these faults could yield large earthquakes similar to the Chi-Chi event.

  7. Permian fauna of the Krkonoše Piedmont Basin (Bohemian Massif, Central Europe)

    Czech Academy of Sciences Publication Activity Database

    Zajíc, Jaroslav

    2014-01-01

    Roč. 70, 3/4 (2014), s. 131-142 ISSN 0036-5343 Institutional support: RVO:67985831 Keywords : faunal lists * palaeogeography * palaeoenvironment * stratigraphy * Early Permian * Krkonoše Piedmont Basin * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy

  8. Tourist Activities-Disturbance Factors of Natural Environment in Ciucaș Massif

    Directory of Open Access Journals (Sweden)

    Luminița Costina SĂFTOIU

    2014-10-01

    Full Text Available The study outlines how tourism activities can disturb the natural environment in Ciucaș Massif. Methods used are based on bibliographic research and GIS analysis of morphometric features. Results show that the Ciucaș Massif, as one of the most important mountain in central Romania, is made of conglomerates, which lend specific features to topography. Having several natural sights (The Old Ladies Council, The Sphinx of Bratocea, Zăganului Ridge this massif is declared a protected natural area. The geomorphologic processes: compactions, mudflows, the deepening of tourist paths, rills and gully erosion have a negative impact on the landscape and even on the entire environment, causing erosion and loss of soil and vegetation. Also, the increased number of tourist accommodation facilities and 21 marked tourist trails have resulted in shrinking of forest areas, hayfields and pastures.These numerous changes which occur in this mountain area, lead, in time, to radical, irreversible changes and can affect the local economic development.

  9. Unstable relationships between tree ring δ18O and climate variables over southwestern China: possible impacts from increasing central Pacific SSTs

    Science.gov (United States)

    An, Wenling; Liu, Xiaohong; Hou, Shugui; Zeng, Xiaomin; Sun, Weizhen; Wang, Wenzhi; Wang, Yu; Xu, Guobao; Ren, Jiawen

    2018-05-01

    In this study, we investigated the potential influence of central and eastern Pacific sea surface temperatures (SSTs) on the unstable relationship between earlywood δ18O and climatic factors in the southwestern China from 1902 to 2005. The results show that the strength of the climate signals recorded in the earlywood δ18O series has declined since the late 1970s. This reduction in signal strength may have been caused by the changes in the local hydroclimate, which is associated with the increasing SSTs in the central Pacific Ocean over recent decades. Alongside these increasing SSTs in the central Pacific, southwestern China has experienced more droughts, as well as more severe droughts through the late spring and early summer during the central Pacific (CP) El Niño years than during the eastern Pacific (EP) El Niño years in recent decades. This increased drought frequency may have weakened the response of earlywood δ18O to climate variables.

  10. Geodynamic movements and deformations of the Sudetic structural unit of the Bohemian Massif

    Science.gov (United States)

    Schenk, V.; Jechumtálová, Z.; Schenková, Z.; Kottnauer, P.

    2003-04-01

    The African plate pushes to European orogenic Alpine structures that transfer the compression further to Variscan structural units, including the Bohemian Massif. Central parts of the Bohemian Massif are relatively deep-seated and, therefore, some of marginal parts of the Massif and its border geological structures should be affected intensively and moved distinctly with respect to the central parts. The geodynamical GPS network EAST SUDETEN is located just over the area mentioned above, i.e. it covers both kinetically quasi-effected and quasi-non-effected structural blocks. GPS data observed already for six annual campaigns (1997-2002) were processed and movement vectors of individual network sites were assessed. Applied data processing did not allow errors in the horizontal direction 2 mm and in the vertical direction 5-6 mm to be exceeded. Since time series of coordinate changes for several network sites gave rather pronounce movement trends, preliminary deformations among individual structural blocks were evaluated and compared to other geological, geophysical and geodetic materials. The investigation has been supported by the Grant Agency of the Czech Republic, projects 205/97/0679 and 205/01/0480, and by the research programme of the Ministry of Education, Youth and Sport of the Czech Republic, project LN00A005 "Dynamics of the Earth".

  11. The hydrothermal alteration in the context of geologic evolution from Pocos de Caldas Alkaline Massif, MG-SP

    International Nuclear Information System (INIS)

    Garda, G.M.

    1990-01-01

    The Pocos de Caldas Alkaline Massif covers 800 km 2 , a quarter of which is hydrothermally altered. Such proportion is uncommon, when compared to the know alkaline massifs of the world. The hydrothermal alteration is associated with Zr, U and Mo mineralizations which are predominantly located in the central-southern portion of the massif, in the central-eastern circular structure. The colour of the altered rock (and its soil) in that area is typically whitish beige to yellowish white and is regionally called potassic rock. The Osamu Utsumi Mine, also referred to as the uranium ore of Campo do Cercado, is located 25 Km to the south of Pocos de Caldas City and was explored, from 1977 to 1989, through the open pit method. A sequence of alteration minerals adapted to lowering temperatures should be expected; however, only illite and alkaline feldspar are observed in the hydrothermally altered portions of the massif, and their formation must have been controlled mainly by kinetic, other than thermal factors. The irrestrict circulation of relatively hotter hydrothermal fluids must have happened at the beginning of the process, diminishing immediately after the cooling of the brecciated areas (and the subjacent magmatic body), leading the system to kinetics levels that made subsequent hydrothermal alteration impossible. (author)

  12. Gold and uranium metallogenesis in the framework of Neo-proterozoic crust growth and differentiation: example of the Mayo-Kebbi Massif (Chad) in the Central Africa Orogenic belt

    International Nuclear Information System (INIS)

    Mbaguedje, Diondoh

    2015-01-01

    The Mayo Kebbi massif located in southwestern Chad between the Congo craton in the South, the West African craton in the west and the Sahara meta-craton to the east exposes a segment of Neo-proterozoic juvenile crust accreted in the Central African orogenic belt during the Pan African orogeny. It consists of two greenstone belts (Zalbi and Goueygoudoum) separated by the May Kebbi calc-alkaline batholith complexes and intruded by calc-alkaline high-K granitic plutons. The whole is covered by Phanerozoic sedimentary formations. The greenstone belts contain sulphide zones hosted mainly by meta-plutonic rocks (granodiorites) and meta-basalts and meta-volcaniclastics. The mineralization comprises pyrite, pyrrhotite, arsenopyrite, chalcopyrite, pentlandite, pentlandite silver, pentlandite cobaltiferous, sphalerite, cobaltite. These sulphides are disseminated, aggregated in form of layers or are filling veins and cracks. The greenstones also contain quartz veins with calcite and chlorite comprising a mineralization made of pyrite, chalcopyrite, galena and gold. Gold is present both as native crystals and as electrum. The high-K calc-alkaline Zabili granitic pluton hosts uranium mineralization related to a superposition of: (1) ductile deformation and metasomatic alteration implying the interaction between magmatic minerals with a Na-rich fluid, of potential magmatic origin, coeval to the main deposition of uranium oxides, followed by (2) brittle deformation and deposition of secondary hydrated uranium silicates involving a Na-Ca-rich fluid. We propose that these uranium mineralizations represent the extreme expression of crustal differentiation as a result of Pan-African reworking of a Neo-proterozoic juvenile crustal segment. (author) [fr

  13. The Alleret Maar lacustrine sequence (French Massif Central): a 150 ka long early-middle Pleistocene continental paleoenvironmental record.

    Science.gov (United States)

    Nomade, S.; Pastre, J.; Guillou, H.; Gauthier, A.; Scaillet, S.

    2008-12-01

    Lacustrine maar sequences of the French Massif Central are of great interest for paleoclimatic and paleoenvironmental reconstructions of mid-latitudes Quaternary continental environments. In particular, the western Velay region yields exceptional sequences spanning the last 450 ka (Reille et al., J. Quat. Sci. 2000). However, older sequences remain largely unknown despite the presence of interbedded alkaline tephras allowing precise absolute radiochronological control of many lacustrine squences. The Alleret maar is a 1500 m wide phreatomagmatic crater that provides a long lacustrine sequence (41 m). The upper part of this sequence (AL2 core, 14.6 m) was studied between 2005 and 2006 (Pastre et al., C. R. Acad Sci, 2007). A 39Ar/40Ar date (557 ± 5ka) obtained from an interbedded tephra layer located at 7m as well as the associated pollen data attribute the beginning of this sequence to the MIS 15. Thanks to the AL3 core recovered in 2005 (40.6 m, CNRS Meudon) several new tephra layers were discovered in the bottom part of this lacustrine sequence. Three new 39Ar/40Ar ages (single crystal analyses) from trachytic tephra layers were obtained at the LSCE Argon Laboratory (France). These layers are located at -30.2, -36.2 and -39.2m. Ages obtained relative to the ACR-2 flux standard (1,201Ma, Kuiper et al., Science, 2008) range from 692 ± 6 ka (MSWD: 2.3, n=18) for the youngest (-30.2m) to 726 ± 9Ka Ka (MSWD: 2.2, n=12) for the lowest tephra located at -39.2m. These new dates indicate a relatively homogeneous deposition rate of 3.5cm/ka and that the last 10 meters cover the MIS 17-MIS18 period. According to these current radiochronological data the complete lacustrine sequence last more than 150ka. Ongoing sedimentary and pollen studies will allow to extend the paleoenvironmental and paleoclimatic records of the French Massif Central towards the beginning of the early middle Pleistocene.

  14. Uranium favorability of southwestern Oklahoma and north-central Texas

    International Nuclear Information System (INIS)

    Stanton, G.D.; Brogdon, L.D.; Quick, J.V.; Thomas, N.G.; Martin, T.S.

    1977-10-01

    Results are presented of a project to identify and delineate units and (or) facies that are favorable for uranium in the Upper Pennsylvanian and Lower Permian strata of north-central Texas and southwestern Oklahoma. To aid in this evaluation, an assessment of the probable uranium rocks (Wichita and Arbuckle Mountains) was necessary. Surface samples were collected from igneous and sedimentary rocks. Stream-sediment samples were also collected. However, the main emphasis of the investigation of the sedimentary units was on the identification of sedimentary facies trends in the subsurface and an evaluation of the uranium favorability within units studied. The area investigated centers along the Red River, the boundary between Texas and Oklahoma. The project area encompasses approximately 17,000 sq. mi. It includes all or parts of Cooke, Montague, Clay, Wichita, Wilbarger, Hardeman, Baylor, Knox, and Archer Counties in Texas and Love, Jefferson, Cotton, Tillman, Jackson, Stephens, Carter, Comanche, Harmon, and Greer Counties in Oklahoma

  15. The Gondwana Orogeny in northern North Patagonian Massif: Evidences from the Caita Có granite, La Seña and Pangaré mylonites, Argentina

    Directory of Open Access Journals (Sweden)

    Daniel A. Gregori

    2016-07-01

    Full Text Available Structural analyses in the northern part of the North Patagonia Massif, in the foliated Caita Có granite and in La Seña and Pangaré mylonites, indicate that the pluton was intruded as a sheet-like body into an opening pull-apart structure during the Gondwana Orogeny. Geochronological studies in the massif indicate a first, lower to middle Permian stage of regional deformation, related to movements during indentation tectonics, with emplacement of foliated granites in the western and central areas of the North Patagonian Massif. Between the upper Permian and lower Triassic, evidence indicates emplacement of undeformed granitic bodies in the central part of the North Patagonian Massif. A second pulse of deformation between the middle and upper Triassic is related to the emplacement of the Caita Có granite, the development of mylonitic belts, and the opening of the Los Menucos Basin. During this pulse of deformation, compression direction was from the eastern quadrant.

  16. Sr isotope stratigraphy of some Rupelian carbonated laminites from the Limagne Basin: influence of seawater in the rift of the French Massif central?

    International Nuclear Information System (INIS)

    Briot, D.; Poidevin, J.L.

    1998-01-01

    87 Sr/ 86 Sr ratios of biogenic and abiotic calcites Upper Rupelian sediments in the Limagne rift (French Massif Central) define a smooth and regular negative correlation with time interrupted by repetitive sharp peaks; the progressive drop in isotopic ratio can be explained by the geological evolution of the river basin through time. Negative peaks are explained by synsedimentary volcanism, repeated marine incursions, or leaching of ancient evaporites. Comparison with available paleontologic data does not favour the volcanic explanation, but rather the influence of Rupelian marine waters. (authors)

  17. Quelques phases granitiques intrusives dans le Massif des Trois Seigneurs

    NARCIS (Netherlands)

    Nieuwenhuys, W.H.

    1956-01-01

    Pendant les étés de 1953, 1954 et 1955 j’ai effectué des travaux de terrain dans le Massif des Trois Seigneurs, Pyrénées orientales, sous la direction du Professeur L.U. de Sitter. Ces travaux de terrain comprennent entre autres le levé d’une carte géologique de la partie centrale et Sud-Ouest de ce

  18. Short Term vs Long Term Environmental Reconstruction from Carbonated Deposits of the Limagne Area (Massif Central, France)

    Energy Technology Data Exchange (ETDEWEB)

    Barbecot, F.; Gibert, E.; Amokrane, Y.; Massault, M.; Noret, A. [Centre National de la Recherche Scientifique Interaction et Dynamique des Environnements de Surface, Universite Paris (France); Ghaleb, B. [Geotop, Universite du Quebec a Montreal, Montreal (Canada)

    2013-07-15

    A 80 cm sequence has been cored from carbonated travertine in the limagne area (French Massif Central, France) in order to document recent environmental fluctuations (0-100 a) of gaseous springs, in relation to the environmental and geochemical parameters that control the isotopic signatures of modern carbonate deposits. The chronology of these finely laminated deposits that are ideal for reconstructing hydrological conditions at very narrow time steps is determined through AMS-{sup 14}C and {sup 210}Pb/{sup 226}Ra radiometric methods. Preliminary results highlight a high enrichment in stable isotopes (eg up to +8 per mille vs VPDB for {delta}{sup 13}C), likely linked to both recharge temperature and degassing processes. Moreover, two general trends are superimposed: the first one, cyclic, may be correlated to the hydrologic annual/biannual budget while the second one, linear, implies a long term environmental trend. (author)

  19. Features of change of permanent snow patches in the Mongun-Taiga Massif, 1966–2011

    Directory of Open Access Journals (Sweden)

    D. A. Ganyushkin

    2013-01-01

    Full Text Available The article is dedicated to perennial snow patches of Mongun-Taiga mountain massif (south-western Tuva, their morphology, present state and dynamics over the last 45 years. We created a scheme of snow patch classification with regard to genesis of relief and position on the slopes. Dynamics of snow patches is analyzed for periods between several time points – 1966 (on basis of aerial photos, 2000, 2007–2008 and 2011 (on basis of field measurements and observations. From 1966 to 2008 the number of snow patches decreased by 4 times, the total area – by 15 times, the altitudinal zone of snow patches moved 250–300 m up. In 2008–2011 the altitudinal zone of snow patches partly recovered, its lower limit moved 250 m down, periglacial snow patches recovered, a new type – snow patches of buried ice and debris-covered glaciers appeared. It could be the first face of the process of small glaciers recovery in the massif. Using the changes of the altitudinal position of snow patches in comparison with data of the closest meteorological station we estimated the amount of annual precipitation, critical for the existence of local snow patches.

  20. Fission track and petrostructural analysis of carbonatic massif of Tamazert ( high central Atlas, Morocco) and neogene reactivation of the north-atlasic fault

    International Nuclear Information System (INIS)

    Ziad, N.; Khazrouni, S.; Tayebi, M.; Bouabdli, A.; Poupeau, G.

    2001-01-01

    The uranium fission-track dating method is used in geochronological survey of basic apatites extracted from the Tamazert complex. The result of this survey coupled with those of petrostructural analysis of this massif enabled as to distinguish three age groups: 32.4 Myr, 23.3 Myr and 12.6 Myr. The first age corresponds to the setting up of the massif, whereas the two other ages indicate later emissions. The setting up of the sill whose age is 12.6 Myr induced a partial rejuvenation of the emission age og the massif. This late volcanic emission is probably related to the north-atlasic fault activity. 4 figs., 1 tab., 30 refs. (au)

  1. Palaeomagnetism in the Sines massif (SW Iberia) revisited: evidences for Late Cretaceous hydrothermal alteration and associated partial remagnetization

    Science.gov (United States)

    Ribeiro, P.; Silva, P. F.; Moita, P.; Kratinová, Z.; Marques, F. O.; Henry, B.

    2013-10-01

    This study revisits the palaeomagnetism of the Sines massif (˜76 Ma) in the southwestern Iberian Margin (Portugal). The palaeomagnetic analysis was complemented by a comprehensive study of the magnetic mineralogy by means of rock magnetic measurements and petrographic observations. The overall dispersion of palaeomagnetic directions (declination ranging between ˜N0° and ˜N50°) and their migration observed during stepwise demagnetizations have revealed the superposition of remanence components. We interpret this complex palaeomagnetic behaviour as related to the regional hydrothermalism associated with the last stages of Late Cretaceous magmatic activity. This environment favoured mineralogical alteration and a partial chemical remagnetization, giving in most samples a composite magnetization, which has been erroneously interpreted as the primary one in a previous study, then leading to a questionable model for Cretaceous Iberia rotation. Nonetheless, for some samples a single component has been isolated. Interesting rock magnetic properties and microscopic observations point to a well-preserved magnetic mineralogy for these samples, with magnetite clearly of primary origin. The associated ChRM mean direction (D/I = 3.9°/46.5°, α95 = 1.7°, N = 31 samples) then represents the true primary magnetization of the Sines massif. This new palaeomagnetic direction and the corresponding palaeomagnetic pole (long = 332.0°, lat = -79.5°, A95 = 1.7°) agrees with those from the other palaeomagnetic works for the same period and region (e.g. the Sintra and Monchique massifs), yielding a lack of significant rotation of Iberia relative to stable Europe since the uppermost Late Cretaceous (Campanian-Maastrichtian).

  2. Hydrogeologic characterization of the Cachoeira Deposit Massif, Caetite, state of Bahia, Brazil

    International Nuclear Information System (INIS)

    Bottura, J.A.; Albuquerque Filho, J.L.; Ojima, L.M.

    1984-01-01

    The hydrogeologic applications for the characterization of rock massifs in future mining activity areas are presented. The study was performed in the Cachoeira uranium deposit (Anomaly no.13 - Lagoa Real Project) located in the south-central portion of the state of Bahia, Caetite municipality, belonging to the Brazilian Nuclear Enterprise - NUCLEBRAS. The massif occuring in the area is composed of a group or series of rocks classified generically as gneisses, displaying different geotechnical classes. In order to consubstantiate the hydrogeologic/ hydrogeotechnical characterization, pumping and infiltration tests were performed, as well as periodic water level measurements in piezometers and drill-holes. In this manner, a hydrogeotechnical classification was made possible and a quantitative evaluation of the volume of water that will be drained was elaborated, orviding necessary contributions for research diggings and exploration. (D.J.M.) [pt

  3. Tephras in lacustrine sediments of the Sarliève marsh (French Massif Central): age and preservation

    Science.gov (United States)

    Fourmont, Agathe; Macaire, Jean-Jacques; Bréhéret, Jean-Gabriel; Argant, Jacqueline; Prat, Béatrice; Vernet, Gérard

    2006-12-01

    The Sarliève marsh sediments (Massif Central, France) contain two tephras. The first tephra [ 13.7±0.4ka(2δ), ca. 12 000 BP], regionally well known, enables to date the beginning of lacustrine infill to the Lateglacial. The second tephra, the 'tephra de Sarliève', the emitting volcano of which is unknown, would be dated to around the Early Subboreal from pollen data. This occurrence, after the discovery of the 'tephra de Beaunit', emphasizes that volcanic eruption(s) occurred in the 'Chaîne des Puys' or in the volcanic Cézallier more than 1000 years after the last known eruption (Pavin) in the 'Chaîne des Puys' at around 6.6/6.7 ka (5800/5900 BP). In the Sarliève piles, these tephras, well preserved in thick and more silicated deposits of deltas, were not observed in carbonated basin sediments where they were altered. The abundance of authigenic zeolites formed during the Lateglacial in restricted depocentre lacustrine waters allows us to detect initial CF1 tephra occurrence. To cite this article: A. Fourmont et al., C. R. Geoscience 338 (2006).

  4. Massification to Marketization of Higher Education: Private University Education in Bangladesh

    Science.gov (United States)

    Ahmed, Jashim Uddin

    2016-01-01

    Massification of higher education is a contemporary phenomenon, and Bangladesh is an excellent example of massification in the sector. With increased alertness worldwide among nations, policy-makers and development bodies, massification of higher education is a requirement of time. Increasing number of youth also contribute to the phenomenon…

  5. Isotopic characteristic of meteoric water and groundwater in Ahaggar massif (central Sahara)

    International Nuclear Information System (INIS)

    Saighi, O.; Michelot, J.L.; Filly, A.

    2001-01-01

    The mean contents of both oxygen-18 and deuterium in precipitation from the Ahaggar massif (central Sahara) are: δ 18 O = -3 per mille and 2 H = -15 per mille. The heterogeneity in meteoric events and the great scattering of these isotopic contents can be ascribed to the origins and the histories of air masses. The main contribution comes from the inflow of the Guinean monsoon during summer months. During winter, the N/W winds, arriving in the area from the Moroccan coast, provide some rains. The deuterium excess of these precipitation are up to +10 per mille, indicating that the air masses generating these rains are supplied by the recycling of the continental air moisture. Groundwater resources are produced in some little phreatic aquifers, which are recharged by sporadic wadi floods. Aquifer zones that are the most favourable are located in the valleys and occur as three overlying levels of unequal importance: the alluvial aquifer, the weathered zone of the underlying substratum and the deep aquifer of fissured basement. The alluvial aquifer contain weakly mineralised water (0.3 g/l). Their stable isotopes contents (δ 18 O∼ -2.7 per mille) and 14 C activity of them (> 100 pmc) are comparable to present meteoric water, allowing modern meteoric waters to be identified. The weathered zone groundwater's are more mineralised (0.8 g/l) and its isotopic contents (δ 18 O∼ -4.2 per mille) and intermediate radiocarbon activity, prove their old water component. The basement's groundwater are more mineralised (> 1 g/l) and their very depleted isotopic contents (δ 18 O∼ -9 per mille) diverge clearly from the present precipitation. Furthermore, the absence of 3 H and 14 C activity of them, prove an old heritage, resulting from recharge during the last humid episode of the Holocene. (author)

  6. The "Escarot" gas seep, French Massif Central: CO2 discharge from a quiescent volcanic system - Characterization and quantification of gas emissions

    Science.gov (United States)

    Gal, F.; Leconte, S.; Gadalia, A.

    2018-03-01

    Natural CO2 emissions from the volcanic rocks of the French Massif Central are poorly constrained. It is of interest better to assess the emission of such non-anthropogenic gases that may significantly contribute to the global carbon budget. We quantified the CO2 emissions to the atmosphere in a small area (0.052 km2) located in the Massif Central close to Lake Pavin, the most recent volcanic edifice in metropolitan France. The specific character of this area, known as the Escarot mofette, was earlier studied for soil-gas concentrations only. In June 2017, we used the accumulation chamber method for measuring CO2 flux and related O2 depletion in the gases emitted at the soil/atmosphere interface, resulting in 176 data acquisitions over four days. In addition, 44 soil-gas concentration measurements were made at selected locations. CO2 emission rates are estimated at 8100 ± 1800 tons/year of deep-seated CO2 and at 660 ± 440 tons/year of biologically produced CO2. The uncertainty on these evaluations comes from the high-frequency variability of CO2 efflux in the more emissive areas and from the occurrence of heavy precipitation events. Though unexpected, these events were used for quantifying the decreases in CO2 efflux, which were as high as 500% over a few hours or even days in some locations. However, repeat acquisitions performed under more favourable weather conditions showed errors of commonly accepted amplitude (±15%). The area showed several degassing centres aligned along a NNW-SSE direction that correlates well with known geological structures, proving the ability of soil-gas methods to map hidden faults. The whole area is characterized by strong CO2 enrichment and related O2 depletion, but it is nonetheless possible to detect areas influenced by the rise of deep-seated gases and a few peripheral areas where biological processes dominate (CO2 up to 10% vol.). This study of gas emissions in a non-urban area also provides complementary information that is

  7. Sr and Nd isotope geochemistry of coexisting alkaline magma series, Cantal, Massif Central, France

    International Nuclear Information System (INIS)

    Downes, H.

    1984-01-01

    Sr and Nd isotope analyses are presented for Tertiary continental alkaline volcanics from Cantal, Massif Central, France. The volcanics belong to two main magma series, silica-saturated and silica-undersaturated (with rare nephelinites). Trace element and isotopic data indicate a common source for the basic parental magmas of both major series; the nephelinites in contrast must have been derived from a mantle source which is isotopically and chemically distinct from that which gave rise to the basalts and basanites. 87 Sr/ 86 Sr initial ratios range from 0.7034 to 0.7056 in the main magma series (excluding rhyolites) and 143 Nd/ 144 Nd ratios vary between 0.512927 and 0.512669; both are correlated with increasing SiO 2 in the lavas. The data can be explained by a model of crustal contamination linked with fractional crystallisation. This indicates that crustal magma chambers are the sites of differentiation since only rarely do evolved magmas not show a crustal isotopic signature and conversely basic magmas have primitive isotopic ratios unless they contain obviuos crustal-derived xenocrysts. Potential contaminants include lower crustal granulites or partial melts of upper crustal units. Equal amounts of contamination are required for both magma series, refuting hypotheses of selective contamination of the silica-saturated series. The isotopic characteristics of the apparently primary nephelinite lavas demonstrates widespread heterogeneity in the mantle beneath Cantal. Some rhyolites, previously thought to be extremely contaminated or to be crustally derived, are shown to have undergone post-emplacement hydrothermal alteration. (orig.)

  8. Understanding karst environments by thermo-hygrometric monitoring: preliminary results from the Cesi Mountain karst system (Central Italy

    Directory of Open Access Journals (Sweden)

    Lucio Di Matteo

    2016-06-01

    Full Text Available The understanding of karst systems is of paramount importance for the protection and valorisation of these environments. A multidisciplinary study is presented to investigate the possible interconnection between karst features of a karst area located in the south-western part of the Martani chain (Cesi Mountain, Central Italy. This hydrogeological structure contributes to recharge a deep regional aquifer. The latter feeds the high discharge and salinity Stifone springs. In the southwestern part of Martani chain, seven caves have been mapped, five of which are hosted in the Calcare Massiccio Formation. The analysis of thermo-hygrometric data collected since Autumn 2014 into the caves and those from external meteorological stations, showed the timing of the airflow inversion occurring on late winter/early spring and summer/ early autumn. Despite the complexity of the morphology of caves and of conceptual models of airflow pattern, these data seem to indicate that the monitored small caves could be interconnected to a considerably wider cave system. Data here presented coupled with the knowledge on hydrogeological and geological-structural setting of the limestone massif are useful to drive future speleological explorations, aiming to discover new large cavities and to better understand the water recharge process.

  9. Who benefits from free institutional delivery? evidence from a cross sectional survey of North Central and Southwestern Nigeria.

    Science.gov (United States)

    Ajayi, Anthony I; Akpan, Wilson

    2017-09-02

    The reasons for low utilisation of maternal health services in settings where the user-fee removal policy has been implemented continue to generate scholarly debates. Evidence of whether user-fee removal benefits the poor women in underserved settings is scanty and inconsistent. This article examines use of maternal health care services in the context of free maternal healthcare and profiles the beneficiaries of user-fee removal. The study adopted a descriptive design. A three-stage cluster sampling method was used to select a representative sample of 1227 women who gave birth between 2011 and 2015. Questionnaires were administered using a face-to-face interview approach and data generated were analysed using descriptive and inferential statistics. The analysis shows that the use of maternal healthcare services has improved considerably in North Central and Southwestern Nigeria. While socioeconomic and geographical inequality in the use of maternal healthcare services appear to be disappearing in Southwestern Nigeria, it appears to be widening in North Central Nigeria. The findings indicate that 33.6% of women reported to have benefitted from the free child-delivery programme; however, substantial variation exists across the two regions. The proportion of beneficiaries of user-fee removal policy was highest in urban areas (35.9%), among women belonging to the middle income category (38.3%), among women who gave birth in primary health centres (63.1%) and among women who resided in communities where there was availability of health facilities (37.2%). The study concludes that low coverage of the free maternal health programme, especially among women of low socioeconomic status residing in underserved settings is among the reasons for persistent poor maternal health outcomes in the context of free maternal healthcare. A model towards improving maternal health in underserved settings, especially in North Central Nigeria, would entail provisioning of health facilities

  10. Re–Os geochemistry and geochronology of the Ransko gabbro–peridotite massif, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Pašava, J.; Erban, V.

    2013-01-01

    Roč. 48, č. 7 (2013), s. 799-804 ISSN 0026-4598 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : Re–Os * geochronology * gabbro * Bohemian Massif * Ni–Cu mineralization Subject RIV: DD - Geochemistry Impact factor: 2.667, year: 2013

  11. Old inherited zircons in two synkinematic variscan granitoids: the 'granite du Pinet' and the 'Orthogneiss de Marvejols' (Southern French Massif Central)

    International Nuclear Information System (INIS)

    Pin, C.

    1981-01-01

    Two granitic bodies outcropping in the metamorphic basement of the Southern French Massif Central have been studied with the zircon U-Pb method: the Pinet granite (Rouergue area) and the Marvejols orthogneisses (Serie du Lot). It is shown that neither of them are pre-Variscan intrusions but that they were emplaced synkinematically, during the early stages of the Hercynian tectonometamorphic event. As numerous other S-type granitoids, both formations are characterized by an important inherited zircon component, whose apparent age is 1800 +- 200 m.y. Lower intersections with the Concordia curve allow to settle an emplacement age around 350-360 m.y., although the Pinet zircons display a complex pattern, owing both to heterogeneity of the inherited component and to late isotopic disturbances. Regional consequences of the synkinematic character of these S-type granitoids are outlined. It is shown that inherited zircons occurences often hinder accurate dating and the possible petrogenetic significance of the old proterozoic component is discussed. (orig.)

  12. Local Seismicity of the Rainbow Massif on the Mid-Atlantic Ridge

    Science.gov (United States)

    Horning, G.; Sohn, R. A.; Canales, J. P.; Dunn, R. A.

    2018-02-01

    The Rainbow massif, an oceanic core complex located in a nontransform discontinuity on the Mid-Atlantic Ridge (36°N), is notable for hosting high-temperature hydrothermal discharge through ultramafic rocks. Here we report results from a 9 month microearthquake survey conducted with a network of 13 ocean bottom seismometers deployed on and around the Rainbow massif as part of the MARINER experiment in 2013-2014. High rates ( 300 per day) of low-magnitude (average ML 0.5) microearthquakes were detected beneath the massif. The hypocenters do not cluster along deeply penetrating fault surfaces and do not exhibit mainshock/aftershock sequences, supporting the hypothesis that the faulting associated with the exhumation of the massif is currently inactive. Instead, the hypocenters demarcate a diffuse zone of continuous, low-magnitude deformation at relatively shallow (serpentinized ultramafic host rock, and although the seismic network we deployed was not capable of constraining the focal mechanism of most events, our analysis suggests that serpentinization may play an important role in microearthquake generation at the Rainbow massif.

  13. Clockwise rotation of the Santa Marta massif and simultaneous Paleogene to Neogene deformation of the Plato-San Jorge and Cesar-Ranchería basins

    Science.gov (United States)

    Montes, Camilo; Guzman, Georgina; Bayona, German; Cardona, Agustin; Valencia, Victor; Jaramillo, Carlos

    2010-10-01

    A moderate amount of vertical-axis clockwise rotation of the Santa Marta massif (30°) explains as much as 115 km of extension (stretching of 1.75) along its trailing edge (Plato-San Jorge basin) and up to 56 km of simultaneous shortening with an angular shear of 0.57 along its leading edge (Perijá range). Extensional deformation is recorded in the 260 km-wide, fan-shaped Plato-San Jorge basin by a 2-8 km thick, shallowing-upward and almost entirely fine-grained, upper Eocene and younger sedimentary sequence. The simultaneous initiation of shortening in the Cesar-Ranchería basin is documented by Mesozoic strata placed on to lower Eocene syntectonic strata (Tabaco Formation and equivalents) along the northwest-verging, shallow dipping (9-12° to the southeast) and discrete Cerrejón thrust. First-order subsidence analysis in the Plato-San Jorge basin is consistent with crustal stretching values between 1.5 and 2, also predicted by the rigid-body rotation of the Santa Marta massif. The model predicts about 100 km of right-lateral displacement along the Oca fault and 45 km of left-lateral displacement along the Santa Marta-Bucaramanga fault. Clockwise rotation of a rigid Santa Marta massif, and simultaneous Paleogene opening of the Plato-San Jorge basin and emplacement of the Cerrejón thrust sheet would have resulted in the fragmentation of the Cordillera Central-Santa Marta massif province. New U/Pb ages (241 ± 3 Ma) on granitoid rocks from industry boreholes in the Plato-San Jorge basin confirm the presence of fragments of a now segmented, Late Permian to Early Triassic age, two-mica, granitic province that once spanned the Santa Marta massif to the northernmost Cordillera Central.

  14. Uraninite, coffinite and brannerite from shear-zone hosted uranium deposits of the Bohemian Massif (Central European Variscan belt)

    Czech Academy of Sciences Publication Activity Database

    René, Miloš; Dolníček, Z.

    2017-01-01

    Roč. 7, č. 4 (2017), č. článku 50. ISSN 2075-163X Institutional support: RVO:67985891 Keywords : uranium deposits * mineralogy * uraninite * coffinite * brannerite * Moldanubian Zone * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.088, year: 2016 http://www.mdpi.com/2075-163X/7/4/50

  15. Evidence of Variscan and Alpine tectonics in the structural and thermochronological record of the central Serbo-Macedonian Massif (south-eastern Serbia)

    Science.gov (United States)

    Antić, Milorad D.; Kounov, Alexandre; Trivić, Branislav; Spikings, Richard; Wetzel, Andreas

    2017-07-01

    The Serbo-Macedonian Massif (SMM) represents a composite crystalline belt within the Eastern European Alpine orogen, outcropping from the Pannonian basin in the north to the Aegean Sea in the south. The central parts of this massif (south-eastern Serbia) consist of the medium- to high-grade Lower Complex and the low-grade Vlasina Unit. Outcrop- and micro-scale ductile structures in this area document three major stages of ductile deformation. The earliest stage D1 is related to isoclinal folding, commonly preserved as up to decimetre-scale quartz-feldspar rootless fold hinges. D2 is associated with general south-eastward tectonic transport and refolding of earlier structures into recumbent metre- to kilometre-scale tight to isoclinal folds. Stages D1 and D2 could not be temporally separated and probably took place in close sequence. The age of these two ductile deformation stages was constrained to the Variscan orogeny based on indirect geological evidence (i.e. ca. 408-ca. 328). During this period, the SMM was involved in a transpressional amalgamation of the western and eastern parts of the Galatian super-terrane and subsequent collision with Laurussia. Outcrop-scale evidence of the final stage D3 is limited to spaced and crenulation cleavage, which are probably related to formation of large-scale open upright folds as reported previously. 40Ar/39Ar thermochronology was applied on hornblende, muscovite, and biotite samples in order to constrain the age of tectonothermal events and activity along major shear zones. These 40Ar/39Ar data reveal three major cooling episodes affecting the central SMM. Cooling below greenschist facies conditions in the western part of the Vlasina Unit took place in a post-orogenic setting (extensional or transtensional) in the early Permian (284 ± 1 Ma). The age of activity along the top-to-the-west shear zone formed within the orthogneiss in the Božica area of the Vlasina Unit was constrained to Middle Triassic (246 ± 1 Ma). This

  16. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in Mineral Deposit Models for Resource Assessment

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V).

  17. Geological and geophysical investigations at Sierra del Medio massif - Argentine

    International Nuclear Information System (INIS)

    Perucca, J.C.; Llambias, E.; Puigdomenech, H.H.; Cebrelli, E.; Castro, C.E.; Grassi, I.; Salinas, L.I.

    1987-01-01

    Geological investigations were performed at Sierra del Medio (Chubut Province), a mountainous massif of about 25 km by 8 km of migmatic origin, which emerges from a depressed tectonic trench or graben called Pampa de Gastre. The most ancient rocks belong to biotitic and anphibolic schist that passed almost entirely to tonalitoid migmatites with a second process producing granitic rocks. Boreholes were drilled on the basis of conclusions from Landsat satellites imagery and aerial photographic sets, folowed by field work on geological, petrographic, geophysical and hydrogeological features at surface, structural interpretation supported by geostatistical computations. Two sets of boreholes were drilled to investigate subsurface rock behaviour al 300 m depth and 800 m depth respectively, beginning at peripheral places and ending at the central part or selected site. Basic purposes of boreholes were to define structural and petrographic features of the rock massif by a good comprehension of master joints and faulting distribution with its belts of alteration mylonitization or brecciation, mechanical properties of samples, chemical composition and varitions, petrographic facies and mineralogy. Boreholes provided data to investigate joints, faults and dikes as general discontinuities for hydraulic research like permeability or effective hydraulic conductivity, and their geostatistical modelling. Boreholes are also being prepared for geophysical logging from which logthermal ones have already been completed. (Author) [es

  18. Volcanic avalanche fault zone with pseudotachylite and gouge in French Massif Central

    Science.gov (United States)

    Bernard, Karine; van Wyk de Vries, Benjamin

    2017-11-01

    Structures and textures with sedimentological variations at different scales of the lithofacies assemblage help us to constrain the basal kinematic transition from non-depositional to depositional conditions during volcanic avalanche emplacement. In the well-exposed impact-sheared contact along volcanic avalanche fault zone in the French Massif Central, we observe how the granular textures of the pseudotachylite and fault gouge have recorded the propagation of shock wave with granular oscillatory stress. Sequential events of basal aggradation along avalanche fault zone have been established related to fractal D-values, temperature pressure regime and oscillatory stress during slow wave velocity. A typical lithofacies assemblage with a reverse grading shows the pseudotachylite and fault gouge. A cataclastic gradient is characterised by the fractal D-values from 2.7 in jigsaw breccias with pseudotachylite partial melt, to 2.6 in the polymodal gouge. Shock, brecciation and comminution produce cataclastic shear bands in the pseudotachylite and quartz microstructures along the basal contact of the volcanic debris-avalanche deposit. Gouge microstructures show granular segregation, cataclasis with antithetic rotational Riedel shear, and an arching effect between the Riedel shear bands. X-ray microtomography provided 3D microfabrics along the clastic vein in the sandy-gouge. From the available statistical dataset, a few equations have been developed implicating the same cataclastic origin with a co-genetic evolution of lithofacies. An impact wave during primary shear propagation may contribute to produce hydroclastic matrix, pseudotachylite partial melt and proximal gouge thixotropy with v 50m/s and a T < 654 °C. The interseismic period with oscillatory stress is related to crushed clasts and basaltic melt around 800 °C, Riedel shear bands with granular segregation along the fault gouge. The secondary shock by matrix-rich avalanche (ΔP = 10GPa, T ≥ 1000-1500

  19. ECOLOGY-ECONOMICAL ASSESSMENT OF NEW RECLAMATION METHOD FOR CURRENTLY WORKING TECHNOGENIC MASSIFS

    Directory of Open Access Journals (Sweden)

    Alexey Strizhenok

    2017-01-01

    Full Text Available One of the most relevant problems of the mining industry is the need to reduce the negative impact of technogenic massifs formed by wastes of extraction and processing of mineral raw materials. This problem has a significant meaning for currently used massifs, because traditional ways of reclamation are not suitable for them. The article describes the results of a scientific study on the development of the most efficient reclamation method for currently used technogenic massifs. Described in detail the main results of the field observations, methods and equipment of laboratory experiments conducted to determine agro-chemical properties of the soil and optimal composition of binder agent. The article also provides ecological and economic assessment of the proposed method of reclamation. The study was conducted on the example of the real technogenic massif, formed by wastes of phosphorus ore processing.

  20. U-Pb La-ICP-ms geochronology and regional correlation of middle Jurassic intrusive rocks from the Garzon Massif, Upper Magdalena Valley and central cordillera, southern Colombia

    International Nuclear Information System (INIS)

    Bustamante, Camilo; Cardona, Agustin; Bayona, German; Mora, Andres; Valencia, Victor; Gehrels, George; Vervoort, Jeff

    2010-01-01

    New U-Pb zircon geochronology from four granitic units sampled along a southeast-northwest transect between the Garzon massif and the Serrania de las Minas (central cordillera), records a middle Jurassic magmatic activity with two different spatio-temporal domains at ca. 189 ma and 180-173 ma. Reconnaissance data suggest that the four granitoids are characterized by mineralogical and geochemical characteristics akin to a continental magmatic arc setting. The new results suggest that the southern Colombian continental margin includes remnants of tectonomagmatic elements formed by the subduction of the Farallon plate under the South American continental margin. This middle Jurassic arc magmatism is part of the broader Andean scale arc province, and is significant for understanding the tectonic and paleogeographic scenario that characterized the Mesozoic tectonic evolution of the northern Andes.

  1. Developing the lithotectonic framework and model for sulphide mineralization in the Jebilet Massif, Morocco: implications for regional exploration

    OpenAIRE

    Lusty, Paul A.J.; Goodenough, Kathryn M.; Essaifi, Abderrahim; Maacha, Lhou

    2015-01-01

    The central Jebilet massif, part of the North African Variscan Belt, hosts significant polymetallic sulphide mineralization. It is generally considered syngenetic and has many features of volcanogenic massive sulphide (VMS) mineralization. However, some characteristics are not compatible with a classic VMS model and two alternative scenarios for formation have been proposed. Our preliminary research favours a complex, multi-stage development of the sulphide deposits...

  2. Peculiarity of rock massif deformation under explosion impact (by the example of Zarechie area of the Semipalatinsk Test Site)

    International Nuclear Information System (INIS)

    Gorbunova, Eh.M.

    2003-01-01

    The paper systematize the results of study of man-caused situation formed outside the central zone of underground nuclear explosion (CZ UNE), at a testing area of the Semipalatinsk Test Site (STS) - Zarechie. The consequence effects of nuclear testing appeared in the rock massif and on the ground surface in the radius of 0.3-5 km from event epicenter are described. (author)

  3. Grand Sarcoui volcano (Chaîne des Puys, Massif Central, France), a case study for monogenetic trachytic lava domes

    Science.gov (United States)

    Miallier, D.; Pilleyre, T.; Boivin, P.; Labazuy, P.; Gailler, L.-S.; Rico, J.

    2017-10-01

    The Grand Sarcoui is a prominent trachytic volcano of the intraplate Quaternary volcanic field of Chaîne des Puys (Massif Central, France), which fulfills basic requirements for being qualified as monogenetic. Grand Sarcoui looks like a simple axisymmetric lava dome, but close observation reveals a complex and dissymmetric structure and composition. The construction of the dome, about 12.5 ka ago, combined both endogenous and exogenous growth which resulted in variable modes of emplacement and textures of the lava. One of its most interesting features is a large ( 0.29 106 m2) fan of deposits bearing hummocks and secondary hydro-eruption craters. Cross sections of these deposits demonstrate that they originated from a sector collapse accompanied by a blast-like event. The dome is covered by a thin layer of lapilli and ash, attributed to a delayed summit eruption which occurred about 10.6 ka ago, surprisingly late after its construction. So, this volcano has, at a reduced scale, features that are more usually observed in large composite volcanoes. However, some of these features differ slightly from those that have been documented to date, and they remain partly unexplained. This shows that monogenetic, well preserved, trachytic lava domes, are uncommon and poorly known, unlike rhyolitic, andesitic and dacitic domes.

  4. Social Class Barriers of the Massification of Higher Education in Taiwan

    Science.gov (United States)

    Ru-Jer, Wang

    2012-01-01

    In recent years, the rapid growth of higher education in Taiwan has led to an essential shift from education for the elite to the massification of higher education. Although this massification is making higher education more accessible, one of the main concerns is whether opportunities for higher education are the same among all social classes in…

  5. Transit traverse in Missouri, 1900-1937. Part 5, Southwestern Missouri, 1900-37

    Science.gov (United States)

    Staack, John G.

    1940-01-01

    This bulletin, which for convenience is to be published in eight parts, contains the results of all transit traverse* done In Missouri through 1937 by the Geological Survey, United States Department of the Interior, including those heretofore published. (See page X.) Each of the parts deals with one of eight sections into which the State has been divided for this purpose and which have been designated northeastern, northwestern, southeastern, southwestern, central, east-central, south-central, and west-central Missouri. In each part descriptions of the points for which geodetic positions have been determined are listed according to the quadrangles in which the points occur. Results of transit traverse other than that done by the Geological Survey have not been included.Southwestern Missouri, as the term is used in this bulletin and as the subject of part 5 of the bulletin, is that section of the State lying south of latitude 38°00' and west of longitude 93°00'.

  6. Geochemical Signature of Magmatic-Hydrothermal Fluids Exsolved from the Beauvoir Rare-Metal Granite (Massif Central, France: Insights from LA-ICPMS Analysis of Primary Fluid Inclusions

    Directory of Open Access Journals (Sweden)

    Matthieu Harlaux

    2017-01-01

    Full Text Available The Beauvoir granite (Massif Central, France represents an exceptional case in the European Variscan belt of a peraluminous rare-metal granite crosscutting an early W stockwork. The latter was strongly overprinted by rare-metal magmatic-hydrothermal fluids derived from the Beauvoir granite, resulting in a massive topazification of the quartz-ferberite vein system. This work presents a complete study of primary fluid inclusions hosted in quartz and topaz from the Beauvoir granite and the metasomatized stockwork, in order to characterize the geochemical composition of the magmatic fluids exsolved during the crystallization of this evolved rare-metal peraluminous granite. Microthermometric and Raman spectrometry data show that the earliest fluid (L1 is of high temperature (500 to >600°C, high salinity (17–28 wt.% NaCl eq, and Li-rich (Te100 m and interaction with external fluids.

  7. Detection of rock strength at Branisko massif

    Directory of Open Access Journals (Sweden)

    Lazarová Edita

    2000-09-01

    Full Text Available When monitoring and optimizing the driving proces of the exploratory gallery by a computer system, conditions for verification of the interaction between desintegrating head of driving machine and rock massif were created. One of the output values of this mathematical model is the model strength at a simple pressure ótlH, which is defined as a pressure at the discus and the massif contact during the desintigration (a near limit of massif strength. By geological and geological engineering exploration, the section of length 2340 m was divided into fourty-two geological sections and five quasi-homogeneous massif enviroments. In the article, results of scleroscopic strength óCI , the strength in a simple pressure determined from the point load test and the strength at simple pressure ótlH are confronted . The main advance of the electronic geomechanical monitoring is the density of gained information. The two-seconds sample period of input and output data during the driving process makes it possible to describe driving circumstances in an almost continual way for each millimeter of the built tunnel. Then the information about changes of disintegrated rock properties, have the same density (frequency. By comparing a quantity of data gained by examining the index of point strength, scleroscopic strength and the model strength in a simple pressure from the monitoring process of driving process it is obvious that during the driving of exploratory gallery of motorway tunnel Branisko, a proportion of data number from the three “type examinations” of strength was reached and it was approximately 1:7:5000. Approximately in the same proportion, there were determined values for the 42 geologic sections (I. – XLII., which were defined in detail by the geologic, engineering geologic, hydrogeologic and geotechnic research.. The presented quantity values of presented rock mass strength for each geologic section are presented by their arithmetic average

  8. Pb and O isotope systematics in granulite facies xenoliths, French Massif Central: Implications for crustal processes

    International Nuclear Information System (INIS)

    Downes, H.; Kempton, P.D.; Harmon, R.S.; Briot, D.; Leyreloup, A.F.

    1991-01-01

    Pb and O isotope data are represented for a suite of granulite facies xenoliths found within Tertiary alkaline volcanic rocks of the Massif Central, France. The suite consists of ultramafic and mafic cumulates, metagabbros which are considered to represent basic liquids, felsic meta-igneous lithologies (charnockites) and metasediments. Ranges of δ 18 O values are +6.9 to +9.8per mille for mafic xenoliths, +9.3 to +10.2per mille for felsic meta-igneous samples and +6.1 to +11.8per mille for the metasediments. By comparison, δ 18 O values for mantle peridotites from the same region range from +5.1 to +6.9per mille, whilst local Hercynian granitoids vary from +8.6 to +12.0per mille. The 206 Pb/ 204 Pb ratios of the granulite xenoliths are between 17.77 and 19.19, 207 Pb/ 204 Pb ratios vary from 15.51 to 15.69, and 208 Pb/ 204 Pb ratios range from 38.07 to 40.07. In general, metasedimentary granulites have the more radiogenic Pb isotope compositions, whereas mafic meta-igneous samples are less radiogenic. These isotopic characteristics can be explained as the result of the interaction of mafic magmas with the metasedimentary crust into which they intruded. The release of heat also provoked melting of the more fusible parts of the lower crust and led to the formation of late-orogenic Hercynian granitoids. However, an additional component which provides less radiogenic Pb is also needed in the source of the granitoids; this may be the felsic meta-igneous xenoliths or middle/upper crustal gneisses. (orig.)

  9. Characterization of the paleo-hydrothermal fluids flow in the geothermal province of Limagne. (French Massif Central).

    Science.gov (United States)

    Fréville, K.; Sizaret, S.

    2017-12-01

    Exploitation of the geothermal energy is a prime target to future energy supply. Understanding the nature and the flow of geothermal fluids is a key objective for describe the functioning of current hydrothermal systems. Located in the French Massif Central, the Limagne basin is a tertiary hemi-graben characterized by a high thermal gradient with numerous occurrences of CO2-rich thermo-mineral waters. This basin has potential for high-temperature geothermal energy, expressed by numerous natural high temperature water sources, as well as at Royat and Vichy were the surface temperature of the water can reach 33°C and 27°C, respectively. In order to better localize this potential, the geological evolution has to be deciphered. In this aim we study the flow processes of the paleo-fluids and estimate the direction and the velocity of the hydrothermal flow from the studies of the growth bands of comb quartz grain localized in vein. In a second time, the studies fluids inclusions within the quartz grain are used to characterize the nature of the fluids involved. Preliminary results show that the flow is discontinuous over the time with changes in velocities and directions during the growth of a single quartz grain. Two main flows were identified, i) a relatively fast upward flow at 10-6,-5 m.s-1; ii) a downward flow at about 10-5,-4 m.s-1. The results allow: (i) to discuss the processes controlling the fluids flow in the Limagne basin; and (ii) to suggest to delimitate the areas with high geothermal potential which integrate the flow variation in time.

  10. Massification of Higher Education and Students' Accommodation ...

    African Journals Online (AJOL)

    Massification of Higher Education and Students' Accommodation: The ... of students' accommodation at the University of Dar es salaam (UDSM) over the past 50 years. ... and the quality of learning, as well as the quality of students' life.

  11. Primary discussion on the characteristics and metallogenesis of Lingshan composite massif in northeastern Jiangxi province

    International Nuclear Information System (INIS)

    Zhang Ping; Tian Bangsheng

    2005-01-01

    A large amount of measured data has been applied to elaborate magmatic metallogenesis of Lingshan composite massif in northeastern Jiangxi Province, and to set up a metallogenetic model for polymetallic deposits, the detailed description on the characteristics of Nb-Ta, W-Sn and Pb-Zn deposits have been given. It is suggested that the Lingshan composite massif is of a ring-like multiphase batholith. Both differences and regular changes exist in following aspects such as spatial distribution, petrology, petrochemistry, microelements, REE and so on. The genetic type of the massif is regarded as A-type granite. Important mineral resources associated with the massif are Nb-Ta, W-Sn and Pb-Zn deposits. (authors)

  12. Mohorovicic discontinuity depth analysis beneath North Patagonian Massif

    Science.gov (United States)

    Gómez Dacal, M. L.; Tocho, C.; Aragón, E.

    2013-05-01

    The North Patagonian Massif is a 100000 km2, sub-rectangular plateau that stands out 500 to 700 m higher in altitude than the surrounding topography. The creation of this plateau took place during the Oligocene through a sudden uplift without noticeable internal deformation. This quite different mechanical response between the massif and the surrounding back arc, the short time in which this process took place and a regional negative Bouguer anomaly in the massif area, raise the question about the isostatic compensation state of the previously mentioned massif. In the present work, a comparison between different results about the depth of the Mohorovicic discontinuity beneath the North Patagonian Massif and a later analysis is made. It has the objective to analyze the crustal thickness in the area to contribute in the determination of the isostatic balance and the better understanding of the Cenozoic evolution of the mentioned area. The comparison is made between four models; two of these were created with seismic information (Feng et al., 2006 and Bassin et al., 2000), another model with gravity information (Barzaghi et al., 2011) and the last one with a combination of both techniques (Tassara y Etchaurren, 2011). The latter was the result of the adaptation to the work area of a three-dimensional density model made with some additional information, mainly seismic, that constrain the surfaces. The work of restriction and adaptation of this model, the later analysis and comparison with the other three models and the combination of both seismic models to cover the lack of resolution in some areas, is presented here. According the different models, the crustal thickness of the study zone would be between 36 and 45 Km. and thicker than the surrounding areas. These results talk us about a crust thicker than normal and that could behave as a rigid and independent block. Moreover, it can be observed that there are noticeable differences between gravimetric and seismic

  13. Petrogenesis of the Cenozoic alkaline volcanic rock series of the České Středohoří Complex (Bohemian Massif), Czech Republic: A case for two lineages

    Czech Academy of Sciences Publication Activity Database

    Dostal, J.; Schellnutt, J. G.; Ulrych, Jaromír

    2017-01-01

    Roč. 317, June (2017), s. 677-706 ISSN 0002-9599 Institutional support: RVO:67985831 Keywords : Bohemian Massif * Central European volcanic province * continental alcaline volcanism * fractional crystallization * magmatic fluids Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 4.099, year: 2016

  14. An overview on geochemistry of Proterozoic massif-type ...

    Indian Academy of Sciences (India)

    A critical study of 311 published WR chemical analyses, isotopic and mineral chemistry of ... Keywords. Massif anorthosite complexes; overview; geochemistry; high-Al gabbro. J. Earth ...... (123–2920 ppm) unlike the experimental results of.

  15. TOURISTIC POTENTIAL, MANAGEMENT AND DEVELOPMENT IN THE RARĂU MASSIF

    Directory of Open Access Journals (Sweden)

    Dinu OPREA-GANCEVICI

    2011-06-01

    Full Text Available As a socio-economic activity, tourism is strongly influenced by numerous factors that determine the size and direction of tourist flows. Mountain tourism is no exception; the mountainous land relief, which generates this type of tourism, possesses a large array of factors which, by definition, represent true attractions for tourists (morphometric elements, types and landforms, oxygen-rich air, specific flora and fauna, but also several factors that may inhibit tourist activity proper (development capacity, climate, natural phenomena hazards.In particular, with reference to the Rarău Massif, we shall emphasize its tourist potential, especially the geomorphologic one, but we shall also highlight the evolution and the present state of infrastructure (accommodation facilities, tourist paths. The cartographic analysis and representation were obtained using dedicated software, generically called Geographic Informatics Systems (GIS, and a social research method as well – the questionnaire. As such, our research features several maps that highlight the differentiated land relief potential as well as the potential resulted from the application of questionnaires, thus bringing into the foreground the areas with maximal morphologic attractiveness and implicitly potential for tourist activity. In order to make the most of the entire massif and to diversify tourist routes we propose new itineraries with a view to covering the entire area more effectively and offering new exploration variants for the massif. The applied questionnaire proves the connection between the tourist potential of land relief and tourists’ perceptions of the tourist sights in the Rarău Massif.

  16. Multidisciplinary characterisation of sedimentary processes in a recent maar lake (Lake Pavin, French Massif Central and implication for natural hazards

    Directory of Open Access Journals (Sweden)

    E. Chapron

    2010-09-01

    Full Text Available Sedimentation processes occurring in the most recent maar lake of the French Massif Central (Lake Pavin are documented for the first time based on high resolution seismic reflection and multibeam bathymetric surveys and by piston coring and radiocarbon dating on a sediment depocentre developed on a narrow sub aquatic plateau. This new data set confirms the mid Holocene age of maar lake Pavin formation at 6970±60 yrs cal BP and highlights a wide range of gravity reworking phenomena affecting the basin. In particular, a slump deposit dated between AD 580–640 remoulded both mid-Holocene lacustrine sediments, terrestrial plant debris and some volcanic material from the northern crater inner walls. Between AD 1200 and AD 1300, a large slide scar mapped at 50 m depth also affected the southern edge of the sub aquatic plateau, suggesting that these gas-rich biogenic sediments (laminated diatomite are poorly stable. Although several triggering mechanisms can be proposed for these prehistoric sub-aquatic mass wasting deposits in Lake Pavin, we argue that such large remobilisation of gas-rich sediments may affect the gas stability in deep waters of meromictic maar lakes. This study highlights the need to further document mass wasting processes in maar lakes and their impacts on the generation of waves, favouring the development of dangerous (and potentially deadly limnic eruptions.

  17. The influence of tectonical structures on the stability rock massif in the area of the magnesite deposit Jelšava of the Dúbrava massif

    Directory of Open Access Journals (Sweden)

    Sasvári Tibor

    2002-12-01

    Full Text Available Magnesite deposits Dúbrava and Miková are located in Carboniferous formations between Brádno and Ochtiná (Dúbrava massif. Carboniferous magnesites are, according to the lithostratigraphic division of Early Paleozoic complexes of Gemericum by Bajaník et al. (1983, situated in the Dobšiná Group, more precisely in the upper part of the Ochtiná Formation, in the environment of black schists with intercalation of metabasalts and their pyroclastics. In the lower parts of the formation are small-pebble conglomerates and polymict sandstones. Carbonatic bodies of the Dúbrava massif has the directional length, 4 500 m, course NE-SW, inclination 55-60o to SE and maximal thickness 600 m. A calculation in 1967 indicated above 500 millions kt of reserves whish after a modification of conditional parameters was reduced to its three fifths. Reserves excluded during the second calculation had a higher content of Fe2O3 causing the lowering of fireproof products quality.In the text the structural and stability conditions in the area of the Dúbrava deposit and the Miková deposit of the Dúbrava massif are analysed.

  18. Research of dynamical Characteristics of slow deformation Waves as Massif Responses on Explosions

    Science.gov (United States)

    Hachay, Olga; Khachay, Oleg; Shipeev, Oleg

    2013-04-01

    The research of massif state with use of approaches of open system theory [1-3] was developed for investigation the criterions of dissipation regimes for real rock massifs, which are under heavy man-caused influence. For realization of that research we used the data of seismic catalogue of Tashtagol mine. As a result of the analyze of that data we defined character morphology of phase trajectories of massif response, which was locally in time in a stable state: on the phase plane with coordinates released by the massif during the dynamic event energy E and lg(dE/dt) there is a local area as a ball of twisted trajectories and some not great bursts from that ball, which are not greater than 105 joules. In some time intervals that burst can be larger, than 105 joules, achieving 106 joules and yet 109 joules. [3]. Evidently there are two reciprocal depend processes: the energy accumulation in the attracted phase trajectories area and resonance fault of the accumulated energy. But after the fault the system returns again to the same attracted phase trajectories area. For analyzing of the thin structure of the chaotic area we decided to add the method of processing of the seismic monitoring data by new parameters. We shall consider each point of explosion as a source of seismic or deformation waves. Using the kinematic approach of seismic information processing we shall each point of the massif response use as a time point of the first arrival of the deformation wave for calculation of the wave velocity, because additionally we know the coordinates of the fixed response and the coordinates of explosion. The use of additional parameter-velocity of slow deformation wave propagation allowed us with use method of phase diagrams identify their hierarchic structure, which allow us to use that information for modeling and interpretation the propagation seismic and deformation waves in hierarchic structures. It is researched with use of that suggested processing method the thin

  19. Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif

    International Nuclear Information System (INIS)

    Buil gutierrez, B.; Garcia Sanz, S.; Lago San Jose, M.; Arranz Yague, E.; Auque Sanz, L.

    2002-01-01

    The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

  20. Structural and kinematic evolution of a Miocene to Recent sinistral restraining bend: the Montejunto massif, Portugal

    Science.gov (United States)

    Curtis, Michael L.

    1999-01-01

    The Montejunto massif lies in the apex of a large-scale restraining bend at the southern termination of a sinistral transpressive fault system, in the Lusitanian basin of Portugal. Cenozoic deformation within the Montejunto massif initiated with southerly directed thrusting along the southern boundary of the massif, in association with the development of the E-W oriented Montejunto anticline, probably during the Langhian. Deformation switched to the northern boundary of the massif, in association with a change to NW-directed thrusting and continued development of the Montejunto anticline. The youngest set of structures within the massif is related to the sinistral reactivation of the Arieiro fault system, and steeply inclined bedding. This late phase of deformation represents the accommodation of a component of sinistral displacement across the restraining bend along mechanical anisotropies formed during this progressive Cenozoic deformation event. Variation in the kinematic style of the Main Arieiro fault is related to the angle ( α) between the fault plane and the displacement vector. Where α≈20°, abrupt pene-contemporaneous switches in displacement direction are recorded along the fault, whereas strike-slip kinematics predominate where α<20°. The timing of deformation events in the Montejunto massif is uncertain. However, correlation with the established Cenozoic Africa/Europe plate convergence directions may provide potential temporal constraints.

  1. Hydrogeology of the Olševa massif (Slovenia

    Directory of Open Access Journals (Sweden)

    Jure Krivic

    2002-12-01

    Full Text Available Olševa consists of highly pervious carbonates, forming a relatively big fractured and karstified aquifer. Due to its high-altitude mountainous nature, the aquifer is unpolluted and therefore has to be regarded as a potential source of drinking water for the future.The Olševa aquifer is tectonically divided into three parts. Groundwater from the two smaller aquifers, covering areas of 1,9 and 0,8 km2, located in eastern part of Ol{eva massif, flows toward Northeast into Meža river basin. In spite of several transversal faults, the rest of Olševa massif forms a relatively uniform aquifer that is conveying groundwater in westerly direction towards Rjavica valley. Rjavica valley in Austria represents the discharge area of a majority of groundwater from the main Ol{eva aquifer.

  2. Uranium mineralization in the Bohemian Massif and its exploration

    International Nuclear Information System (INIS)

    Matolin, M.; Pluskal, O.; Rene, M.

    1981-01-01

    Long-term systematic and planned uranium survey including airborne, carborne, ground, logging and laboratory radiometric measurements as well as geological and geochemical investigations have shown a difference in radioactivity of two regional geological units in Czechoslovakia. The higher regional radioactivity of the Variscan granitoid rocks of the Bohemian Massif differs from that of the West Carpathians and is associated with more frequent uranium mineralization. Endogenous vein-type uranium mineralization has a spatial association with high-radioactivity granitoids in the Bohemian Massif. Airborne prospection defined rock radioactivity features on a regional scale while surface and subsurface radiometric and geological investigations using various techniques localized important uranium deposits. Complex statistical evaluation of numerous geophysical and geological data was studied in order to delineate uranium-favourable areas. (author)

  3. Petrology, geochemistry and source characteristics of the Burpala alkaline massif, North Baikal

    Directory of Open Access Journals (Sweden)

    N.V. Vladykin

    2017-07-01

    Full Text Available The Burpala alkaline massif contains rocks with more than 50 minerals rich in Zr, Nb, Ti, Th, Be and rare earth elements (REE. The rocks vary in composition from shonkinite, melanocratic syenite, nepheline and alkali syenites to alaskite and alkali granite and contain up to 10% LILE and HSFE, 3.6% of REE and varying amounts of other trace elements (4% Zr, 0.5% Y, 0.5% Nb, 0.5% Th and 0.1% U. Geological and geochemical data suggest that all the rocks in the Burpala massif were derived from alkaline magma enriched in rare earth elements. The extreme products of magma fractionation are REE rich pegmatites, apatite–fluorite bearing rocks and carbonatites. The Sr and Nd isotope data suggest that the source of primary melt is enriched mantle (EM-II. We correlate the massif to mantle plume impact on the active margin of the Siberian continent.

  4. Radon and lung cancer: protocol and procedures of the multicentre studies in the Ardennes-Eifel region, Brittany and the Massif Central region

    International Nuclear Information System (INIS)

    Poffijn, A.; Darby, S.

    1992-01-01

    As part of a European coordinated project, the Ardennes-Eifel study was set up. In this project the study area coincides more or less with a geological zone, situated partly in France, Belgium, Luxembourg and Germany. In a first phase, a common protocol was worked out, dealing with general items as the selection of cases and (hospital/community) controls, the residential criteria for inclusion in the study and the specifications of the radon measurements. Much attention was given to the disease for the hospital controls and a list of ineligible diseases, most strongly related to tobacco, was agreed upon. A common core questionnaire is used, including items such as residential history since birth, occupational history, exposure to passive smoke (for non-smokers and occasional smokers) and educational attainment of the partner. Each country is also free to include additional items of its own. In France, this case-control study is extended to the granitic region of Britanny and in a second period to the region of the Massif Central. In these studies as well as in the national German study on radon and lung cancer, a protocol in all points comparable to that of the Ardennes study is used. (author)

  5. Geochemical Study of Natural CO{sub 2} Emissions in the French Massif Central: How to Predict Origin, Processes and Evolution of CO{sub 2} Leakage; Etude geochimique des emissions naturelles de CO{sub 2} du Massif Central: origine et processus de migration du gaz

    Energy Technology Data Exchange (ETDEWEB)

    Battani, A.; Deville, E.; Faure, J.L.; Jeandel, E.; Noirez, S.; Tocque, E.; Benoit, Y.; Schmitz, J.; Parlouar, D. [Institut francais du petrole, IFP, 92 - Rueil-Malmaison (France); Sarda, P. [Paris-11 Univ., 91 - Orsay (France); Gal, F.; Le Pierres, K.; Brach, M.; Braibant, G.; Beny, C. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France); Pokryszka, Z.; Charmoille, A.; Bentivegna, G. [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique ALATA, 60 - Verneuil-en-Halatte (France); Pironon, J.; De Donato, P.; Garnier, C.; Cailteau, C.; Barres, O.; Radilla, G.; Bauer, A. [Institut National Polytechnique de Lorraine (INPL), 54 - Vandoeuvre-les-Nancy (France)

    2010-07-15

    This study presents an overview of some results obtained within the French ANR (National Agency of Research) supported Geocarbone-Monitoring research program. The measurements were performed in Sainte-Marguerite, located in the French Massif Central. This site represents a natural laboratory for CO{sub 2}/fluid/rock interactions studies, as well as CO{sub 2} migration mechanisms towards the surface. The CO{sub 2} leaking character of the studied area also allows to test and validate measurements methods and verifications for the future CO{sub 2} geological storage sites. During these surveys, we analyzed soil CO{sub 2} fluxes and concentrations. We sampled and analyzed soil gases, and gas from carbo-gaseous bubbling springs. A one-month continuous monitoring was also tested, to record the concentration of CO{sub 2} both in atmosphere and in the soil at a single point. We also developed a new methodology to collect soil gas samples for noble gas abundances and isotopic analyses, as well as carbon isotopic ratios. Our geochemical results, combined with structural geology, show that the leaking CO{sub 2} has a very deep origin, partially mantle derived. The gas rises rapidly along normal and strike-slip active faults. CO{sub 2} soil concentrations (also showing a mantle derived component) and CO{sub 2} fluxes are spatially variable, and reach high values. The recorded atmospheric CO{sub 2} is not very high, despite the important CO{sub 2} degassing throughout the whole area. (authors)

  6. The Blaník Gneiss in the southern Bohemian Massif (Czech Republic): a rare rock composition among the early palaeozoic granite of Variscan Central Europe

    Czech Academy of Sciences Publication Activity Database

    René, Miloš; Finger, F.

    2016-01-01

    Roč. 110, č. 4 (2016), 503-514 ISSN 0930-0708 R&D Projects: GA MŠk ME 555 Institutional support: RVO:67985891 Keywords : leucogranite * turmaline * petrology * geochemistry * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.236, year: 2016

  7. Lytostratigraphy of the eocene sediments in the Serbian-Macedonian Massif, Republic of Macedonia

    OpenAIRE

    Stojanova, Violeta; Petrov, Gose; Sijakova-Ivanova, Tena

    2017-01-01

    This paper presents the lithostratography of the eocene sedimentary series in the Serbian Macedonian massif on the territory of the Republic of Macedonia. Sediments of Eocene age in the Serbian Macedonian massif are represented in the Delchevo, Deve Bair and Strumi ca basin, with the orientation of NW-SE to S-J. With lithostratigraphic studies of eocene sediments in the basins in SMM, 3 superposition lithostratigraphic units (lithozones) were isolated:...

  8. Two-phase southward subduction of the Mongol-Okhotsk oceanic plate constrained by Permian-Jurassic granitoids in the Erguna and Xing'an massifs (NE China)

    Science.gov (United States)

    Liu, Huichuan; Li, Yinglei; He, Hongyun; Huangfu, Pengpeng; Liu, Yongzheng

    2018-04-01

    Geodynamics of the Mongol-Okhotsk oceanic plate southward subduction are still pending problems. This paper presents new zircon LA-ICP-MS U-Pb age and whole-rock geochemical data for the middle Permian to Middle Jurassic granitoids in the western Erguna and central Xing'an massifs. 267-264 Ma, 241 Ma and 173 Ma I-type granites, and 216 Ma A-type granites were identified in the Erguna and Xing'an massifs (NE China). The I-type granites were produced by partial melting of the lower mafic crust. The 216 Ma A-type granites were derived from partial melting of crustal materials with tonalitic to granodioritic compositions. The 267-264 Ma and 241 Ma I-type granites were generated in an Andean-type arc setting, wheras the 216 Ma A-type and 173 Ma granites were formed in supra subduction extensional setting. We summarized previous age data of the middle Permian to Middle Jurassic magmtaic rocks in the Erguna and Xing'an Massifs and identified two isolated phases of magmatic activity including the ca. 267-225 Ma and ca. 215-165 Ma periods, with a significant magmatic gap at ca. 225-215 Ma. These middle Permian to Middle Jurassic magmatic rocks are closely related to the southward subduction of the Mongol-Okhotsk ocean. A two-stage tectonic evolutionary model was proposed to account for these geological observations in the Erguna and Xing'an massifs, involving Permian to Middle Triassic continuous southward subduction of the Mongol-Okhotsk oceanic plate and Late Triassic to Jurassic slab-rollback and supra subduction extension.

  9. Microbial community diversity and physical-chemical features of the Southwestern Atlantic Ocean

    NARCIS (Netherlands)

    Alves Junior, Nelson; Meirelles, Pedro Milet; de Oliveira Santos, Eidy; Dutilh, Bas; Silva, Genivaldo G Z; Paranhos, Rodolfo; Cabral, Anderson S; Rezende, Carlos; Iida, Tetsuya; de Moura, Rodrigo L; Kruger, Ricardo Henrique; Pereira, Renato C; Valle, Rogério; Sawabe, Tomoo; Thompson, Cristiane; Thompson, Fabiano

    2014-01-01

    Microbial oceanography studies have demonstrated the central role of microbes in functioning and nutrient cycling of the global ocean. Most of these former studies including at Southwestern Atlantic Ocean (SAO) focused on surface seawater and benthic organisms (e.g., coral reefs and sponges). This

  10. Behaviour of uranium during late-Hercynian and alpine metamorphisms in the Aiguilles rouges and Belledonne (Valorcine, Lauziere) massifs. Western Alps

    International Nuclear Information System (INIS)

    Negga, H.S.

    1984-01-01

    The purpose of this research thesis is to define the origin of numerous uranium anomalies in the external crystalline Alpine massifs, more precisely the massif of the Aiguilles Rouges and the massif of Belledonne. The primary cause of uranium mineralization in the first massif appears to have been the retrograde metamorphism events of the late-Hercynian age. In the second massif, the same conditions of uranium mineralization appear to have been realised, but with a much higher calcium activity in the fluids. After having explained the choice of the selected areas, the sampling and the chemical analysis performed, the author describes the geological and structural framework of Western Alps: geological history of the paleozoic platform, regional geology of the studied massifs. The next part reports the petrographic and geochemical study, the analysis of the mineral chemistry, of the alteration and the metamorphism. Then the author describes the geochemistry of uranium and thorium within the studied structures

  11. Geochemical Study of Natural CO2 Emissions in the French Massif Central: How to Predict Origin, Processes and Evolution of CO2 Leakage Étude géochimique des émissions naturelles de CO2 du Massif Central : origine et processus de migration du gaz

    Directory of Open Access Journals (Sweden)

    Battani A.

    2010-05-01

    Full Text Available This study presents an overview of some results obtained within the French ANR (National Agency of Research supported Géocarbone-Monitoring research program. The measurements were performed in Sainte-Marguerite, located in the French Massif Central. This site represents a natural laboratory for CO2/fluid/rock interactions studies, as well as CO2 migration mechanisms towards the surface. The CO2 leaking character of the studied area also allows to test and validate measurements methods and verifications for the future CO2 geological storage sites. During these surveys, we analyzed soil CO2 fluxes and concentrations. We sampled and analyzed soil gases, and gas from carbo-gaseous bubbling springs. A one-month continuous monitoring was also tested, to record the concentration of CO2 both in atmosphere and in the soil at a single point. We also developed a new methodology to collect soil gas samples for noble gas abundances and isotopic analyses, as well as carbon isotopic ratios. Our geochemical results, combined with structural geology, show that the leaking CO2 has a very deep origin, partially mantle derived. The gas rises rapidly along normal and strike-slip active faults. CO2 soil concentrations (also showing a mantle derived component and CO2 fluxes are spatially variable, and reach high values. The recorded atmospheric CO2 is not very high, despite the important CO2 degassing throughout the whole area. Cette étude présente les principaux résultats de campagnes de monitoring géochimique menées en 2006 et 2007 dans le cadre du projet Géocarbone-Monitoring, sur le site de Sainte-Marguerite, situé dans le Massif Central. Ce site constitue un « laboratoire naturel » pour l’étude des interactions CO2/fluides/roches et des mécanismes de migration du CO2 vers la surface, à l’échelle des temps géologiques. Le caractère particulièrement émissif de cet « analogue » permet également de tester et valider des méthodes de mesure et

  12. U-Pb geochronology by La-CIP-MS and petrography of Sao Carlos massif - stanniferous province of Rondonia

    International Nuclear Information System (INIS)

    Debowski, Beatriz P.; Geraldes, Mauro Cesar; Nogueira, Camila; Almeida, Bruna Saar de

    2015-01-01

    U-Pb dating by ICP-MS-LA were performed in four samples of the Massif Sao Carlos massif, representative of the younger Granites of Rondonia belonging to the stanniferous province of the same State. Dated samples are granites of pink in colour and coarse-grained to porphyry with main mineralogy consisting of feldspar pertitic to mesopertitic, quartz, plagioclase in lower proportion, biotite and amphibole in some cases. Ages obtained were 986 ± 14 Ma, 974 ± 10 Ma, ± 8 Ma 992.7 and 996 ± 8 Ma and represent the age of crystallization of the Massif. Such ages are concordant with others reported on the bibliography ratifying the inclusion of the massif in the younger Granites of Rondonia, which are directly associated with the most significant mineralization of cassiterite in the State

  13. Massification and Quality Assurance in Tertiary Education: The ...

    African Journals Online (AJOL)

    The study sets out to examine massification and its impact on quality assurance in tertiary education and the extent to which lecturer–student ratio, adequacy of infrastructure and pedagogical resources affect quality in tertiary institutions. Two research questions and one hypothesis were posed to guide the investigation.

  14. Sm-Nd dating of the Verkhneundytkansky massif of autonomous anorthosites (Aldanian Shield)

    International Nuclear Information System (INIS)

    Sukhanov, M.K.; Lennikov, A.M.; Zhuravlev, D.Z.

    1991-01-01

    Geochronological investigation of four typical rocks of the Verkhneundyransky anorthosite massif as well as rock-forming minerals of one of the samples is carried out by the method of Sm-Nd dating. Model ayes of the investigated rocks which were calculated with respect to the depleted mantle, constitute 2.22-2.35 bullion ylars which well agrees with the isochronous age. The experimental points fall well on the regression line which attests that the crystallization of the investigated massif proceeded rather fast and the latter could not assimilate the crustal matter to a considerable extent

  15. Use of isotopes to study groundwater recharge in arid zones: Application to the crystalline Ahaggar massif (central Sahara)

    International Nuclear Information System (INIS)

    Saighi, O.

    1999-01-01

    In the crystalline and igneous Ahaggar massif, the water resources are found in some small-scale phreatic aquifers which are recharged by sporadic wadi floods. The most favourable aquifer zones are localized in the valleys, consisting of three overlying levels of varying importance: the alluvial aquifer, the weathered zone of the underlying substratum, and the deep aquifer of fissured basement, the extent of which is not limited only to wadis. In order to evaluate the recharge to the different aquifers, chemical and isotopic analyses have been carried out on a hundred samples taken at different depths. Measurements of oxygen-18, deuterium, carbon-13, carbon-14 and tritium have been carried out on these samples

  16. Uranium and thorium in rocks and minerals of Zaangarsk alkaline massif

    International Nuclear Information System (INIS)

    Zhmodin, S.M.; Gofman, A.M.; Ksenzova, V.I.; Malmova, Z.V.; Nemirovskaya, N.A.

    1981-01-01

    U and Th distribution in rocks of the massif of alkaline-granitoid formation is studied using the methods of γ-spectrometry and neutron- fragment radiography. Predominant accumulation of U and Th in final products of magmatic differentiation - foyaites - is established. U and Th concentrations increased sharply during postmagmatic stage of alkaline massif formation - in permatites and metasomatically alterated rocks (Th/U and U/K ratios can serve as criteria for identification of such formations). The increase of U part, connected with accessory minerals in pegmatites and metasomatically alterated rocks, is pointed out. For U in postmagmatically alterated rocks high concentrations due to microcracks are characteristic [ru

  17. The peculiarities of structurizing enclosing rock massif while developing a coal seam

    Science.gov (United States)

    Kozyreva, E. N.; Shinkevich, M. V.

    2017-09-01

    Different concepts of the development of geo-mechanical processes during longwall mining of a seam which are fundamentally different from the conventional ones are introduced in the article. Fundamental principles of the model for structurizing enclosing rock mass while longwall mining along the strike are described. The model was developed on the bases of non-linear geomechanical laws. According to the model, rock mass in the area of mining operation is organized as rock geomechanical layers with shifting arches. And the formation period of shifting arches in disintegrated rock mass is divisible by the length of the stope. Undulate characteristic of a massif as a peculiarity of man-made structurization of a massif is defined. It is shown that structuring the broken massif causes the formation of block-structured system and it can be detected while monitoring the ground pressure in powered support props. The results of the research allow decreasing the negative influence of a ground pressure and can be applied to specify parameters for controlling the roof, defining geometrical dimensions of a mining section and positioning of holing chute (face entry).

  18. Quaternary glaciation of the Lato Massif, Zanskar Range of the NW Himalaya

    Science.gov (United States)

    Orr, Elizabeth N.; Owen, Lewis A.; Saha, Sourav; Caffee, Marc W.; Murari, Madhav K.

    2018-03-01

    The glacial chronostratigraphy and history of the Lato Massif of Zanskar northern India is defined for the first time using geomorphic mapping and 10Be surface exposure dating. Three local glacial stages, the Lato, Shiyul and Kyambu, are dated to 244-49, 25-15 and 3.4-0.2 ka, respectively. The Lato glacial stage was the most extensive period of glaciation, characterized by expanded ice caps with glaciers advancing to ∼16 km from their present position. Large till deposits are associated with this glacial stage, which represent a time of heightened glacial erosion and localized incision, and increased rates of sediment transfer and deposition. The glacial style transitioned to entrenched valley glaciation during the Shiyul glacial stage. Hummocky moraine complexes reflecting fluctuating glacier margins characterize this glaciation. Glaciers have been confined to the cirques and headwalls of the massif during and since the Kyambu glacial stage. Equilibrium-line altitude (ELA) reconstructions help define the shifts in glaciation over time, with ELA depressions changing from 470 ± 140, 270 ± 80 to 100 ± 30 m for the Lato, Shiyul and Kyambu glacial stages, respectively. The change of glacial style during the latter part of the Quaternary is similar to other regions of the Transhimalaya and Tibet suggesting that this pattern of glaciation may reflect regional climatic forcing. The evolution of the Lato Massif from an isolated alpine plateau to a steeply incised massif over the last several glacial-interglacial cycles may have also influenced the shifts from ice cap to valley glaciation.

  19. Genetic Isolation among the Northwestern, Southwestern and Central-Eastern Indian Ocean Populations of the Pronghorn Spiny Lobster Panulirus penicillatus

    Directory of Open Access Journals (Sweden)

    Muhamad Fadry Abdullah

    2014-05-01

    Full Text Available The pronghorn spiny lobster Panulirus penicillatus is a highly valuable species which is widely distributed in Indo-West Pacific and Eastern Pacific regions. Mitochondrial DNA control region sequences (566–571 bp were determined to investigate the population genetic structure of this species in the Indian Ocean. In total, 236 adult individuals of Panulirus penicillatus were collected from five locations in the Indian Ocean region. Almost all individuals had a unique haplotype. Intrapopulation haplotype (h and nucleotide (π diversities were high for each locality, ranging from h = 0.9986–1.0000 and π = 0.031593–0.043441. We observed distinct genetic isolation of population located at the northwestern and southwestern edge of the species range. Gene flow was found within localities in the central and eastern region of the Indian Ocean, probably resulting from an extended planktonic larval stage and prevailing ocean currents.

  20. Deep groundwater quantity and quality in the southwestern US

    Science.gov (United States)

    Kang, M.; Ayars, J. E.; Jackson, R. B.

    2017-12-01

    Groundwater demands are growing in many arid regions and adaptation through the use of non-traditional resources during extreme droughts is increasingly common. One such resource is deep groundwater, which we define as deeper than 300 m and up to several kilometer-depths. Although deep groundwater has been studied in the context of oil and gas, geothermal, waste disposal, and other uses, it remains poorly characterized, especially for the purposes of human consumption and irrigation uses. Therefore, we evaluate deep groundwater quantity and quality within these contexts. We compile and analyze data from water management agencies and oil and gas-based sources for the southwestern US, with a detailed look at California's Central Valley. We also use crop tolerance thresholds to evaluate deep groundwater quality for irrigation purposes. We find fresh and usable groundwater volume estimates in California's Central Valley to increase by three- and four-fold respectively when depths of up to 3 km are considered. Of the ten basins in the southwestern US with the most data, we find that the Great Basin has the greatest proportions of fresh and usable deep groundwater. Given the potentially large deep groundwater volumes, it is important to characterize the resource, guard against subsidence where extracted, and protect it for use in decades and centuries to come.

  1. Three steps of serpentinization in an eclogitized oceanic serpentinization front (Lanzo Massif - Western Alps)

    OpenAIRE

    DEBRET, Baptiste; NICOLLET, christian; ANDREANI, Muriel; SCHWARTZ, Stéphane; GODARD, Marguerite

    2013-01-01

    The Lanzo peridotite massif is a fragment of oceanic lithosphere generated in an ocean-continent transition context and eclogitized during alpine collision. Despite the subduction history, the massif has preserved its sedimentary oceanic cover, suggesting that it may have preserved its oceanic structure. It is an exceptional case for studying the evolution of a fragment of the lithosphere from its oceanization to its subduction and then exhumation. We present a field and petrological study re...

  2. Biodiversity impact of the aeolian periglacial geomorphologic evolution of the Fontainebleau Massif (France)

    Science.gov (United States)

    Thiry, M.; Liron, M. N.

    2009-04-01

    Landscape features The geomorphology of the Fontainebleau Massif is noteworthy for its spectacular narrow ridges, up to 10 km long and 0.5 km wide, armored by tightly cemented sandstone lenses and which overhang sandy depressions of about 50m. Denudation of the sandstone pans lead to a highly contrasted landscape, with sandstone ridges ("platières") towering sandy depressions ("vallées") and limestone plateaus ("monts"). This forms the geological frame of the spectacular sceneries of the Fontainebleau Massif (Thiry & Liron, 2007). Nevertheless, there is little know about the erosive processes that have built-up these landscapes. Periglacial processes, and among them aeolian ones, appear significant in the development of the Fontainebleau Massif physiography. The periglacial aeolian geomorphology Dunes and dune fields are known since long and cover about 15% to 25% of the Fontainebleau Massif. The aeolian dunes developed as well on the higher parts of the landscape, as well as in the lower parts of the landscape. The dunes are especially well developed in the whole eastern part of the massif, whereas the western part of the massif is almost devoid of dunes. Nevertheless, detailed mapping shows that dunes can locally be found in the western district, they are of limited extension, restricted to the east facing backslope of outliers. Loamy-sand covers the limestone plateaus of the "monts". The loam cover is of variable thickness: schematically thicker in the central part of the plateaus, where it my reach 3 m; elsewhere it may thin down to 0,20-0,30 m, especially at the plateau edges. Blowout hollows are "negative" morphologies from where the sand has been withdrawed. Often these blowouts are decametric sized and well-delimited structures. Others, more complex structures, are made up of several elongated hectometric hollows relaying each other from and which outline deflation corridor more than 1 km long. A characteristic feature of these blowout hollows is the

  3. VARIATION OF MACROMYCETES SPECIES COMPOSITION IN TWO FOREST HABITATS FROM GIUMALĂU MASSIF (EASTERN CARPATHIANS, ROMANIA

    Directory of Open Access Journals (Sweden)

    BÎRSAN Ciprian

    2013-12-01

    Full Text Available Norway spruce (Picea abies is the most common species with a large spreading in forests from Giumalău Massif. In this study the authors investigated the macromycetes species composition in two forest communities from Giumalău Massif: Hieracio transsilvanico-Piceetum and Leucanthemo waldsteinii-Fagetum. A total of 243 macromycetes species in 30 sampling areas have been identified. Changes in macromycetes species composition have been related to environmental factors (altitude and vegetation (canopy cover, plant species diversity. The results suggest that variation in macromycetes species composition in the two forests types from Giumalău Massif is directly related to abiotic factors (altitude, woody species composition and plants communities’ structure.

  4. Geophysical research results of buried relief and distribution groundwater runoff of the Aragats massif

    OpenAIRE

    V.P. Vardanyan; A.H. Hovhannisyan

    2017-01-01

    Based on the synthesis and reinterpretation of long-term data of geophysical studies together with the hydrology - hydrological materials it has been received new data about the buried topography and spatial distribution of groundwater runoff of the Aragats massif. First of all, it requires to determine the structure of its buried relief, which is basically a regional relief aquitard. The underground water sources are considered to be precipitation on the massif (approximately 83% of the tota...

  5. Preandean geological configuration of the eastern North Patagonian Massif, Argentina

    Directory of Open Access Journals (Sweden)

    Daniel A. Gregori

    2013-11-01

    Full Text Available The Preandean geological configuration of the eastern North Patagonian Massif is established through the use of geological and geophysical analysis. The positive gravity anomalies located near the Atlantic coast are due to 535 and 540 Ma old rocks belonging to the Pampean Orogeny (Precambrian–middle Cambrian, which are widely recognized in central and northern Argentina. The Famatinian Cycle (Ordovician–Devonian is represented by a Silurian–Devonian marine basin equivalent to those of eastern-central Argentina and South Africa, and which was deformed at the end of the Devonian by an ∼E–W to WNW–ESE compressional event, part of the Famatinian Orogeny. Containing strong gravity gradients, the NW–SE belt is coincident with fault zones which were originated during the Gondwanide Orogeny. This event also produced NW–SE overthrusting of the Silurian–Devonian sequences and strike-slip faults that displaced blocks in the same direction. This deformation event belongs to the Gondwanide Orogeny that includes movements related to a counterclockwise rotation of blocks in northern Patagonia. The strong negative anomalies located in the western part of the area stem from the presence of rocks of the Jurassic Cañadón Asfalto basin interbedded in the Marifil Complex. These volcaniclastic sequences show mild deformation of accommodation zones in a pre-Jurassic paleorelief.

  6. Environmental Management Audit: Southwestern Power Administration (Southwestern)

    International Nuclear Information System (INIS)

    1993-03-01

    This report documents the results of the Environmental Management Audit completed for the Southwestern Power Administration. During this Audit, activities and records were reviewed and personnel interviewed. The onsite portion of the Southwestern Audit was conducted from November 30 through December 11, 1992, by the US Department of Energy's Office of Environmental Audit (EH-24). EH-24 carries out independent assessments of Department of Energy (DOE) facilities and activities as part of the Assistant Secretary's Environmental Audit Program. This program is designed to evaluate the status of DOE facilities/activities regarding compliance with laws, regulations, DOE Orders, formal written procedures, compliance agreements, and Best Management Practices (BMPs). This internal oversight function plays an important role in improving the compliance status of DOE operations. The Environmental Management Audit stresses DOE's policy that it is the responsibility of line management to conduct operations in an environmentally sound and safe manner. The Environmental Management Audit focuses on management systems and programs, whereas the Environmental Baseline Audit conducted in March 1991 focused on specific compliance issues. The scope of the Southwestern Environmental Management Audit included a review of all systems and functions necessary for effective environmental management. Specific areas of review included: Organizational Structure; Environmental Commitment; Environmental Protection Programs; Formality of Environmental Programs; Internal and External Communication; Staff Resources, Training, and Development; and Program Evaluation, Reporting, and Corrective Action

  7. Tectonic evolution of part of the Southern Metamorphic Belt of the Armorican Massif including the Ile de Groix

    Science.gov (United States)

    Richards, Lawrence Edward

    The Southern Metamorphic Belt (SMB) of the Armorican Massifextends 400km along the south coast of Brittany and into Vendee. It is separated from the Central Armorican Domain by a major, late-Hercynian shear belt, known as the South Armorican Shear Zone. In the area studied, belts of metasedimentary and metavolcanic schist of uncertain age are separated by belts of granitic gneiss; areas of migmatite and Hercynian granite plutons cross-cut these belts. Three distinctive lithologic assemblages have been identified in the schist belts, characteristic of different depositional environments: the Le Pouldu Group, Kerleven and Gouesnach formations probably originated as abyssal black shales deposited on oceanic crust; the St. Laurent Formation and Melgven Schists probably formed as distal greywacke deposits on a deep continental shelf; the Nerly and Beg-Meil formations probably formed in a proximal marine or fluviatile environment. These disparate assemblages were tectonically juxtaposed by overthrusting (obduction) before an amphibolite facies metamorphism and deformation during the Cadomian Orogeny. The Moelan Gneiss, a Lower Ordovician alkali-granite intrusion, postdates M1/D1 and probably formed in a rifting environment at the onset of ocean-floor spreading along an axis south of the present Armorican Massif. The famous blueschists of the Ile de Groix probably formed in a subduction zone on the south side of the ocean and were obducted onto the passive southern margin of the Armorican Massif following closure of the ocean and continental collision. A second phase of regional deformation, producing a cataclastic foliation in the Moelan Gneiss, probably resulted from the collision. Large-scale overthrusting of the southern continent onto the Armorican Massif took place, causing metamorphism with partial melting at depth generating migmatites. A third phase of pervasive deformation may correlate with oroclinal bending of the Ibero-Armorican Arc during the Hercynian

  8. Geology of the Menderes Massif and the Lycian Nappes South of Denizli, Western Taurides

    Directory of Open Access Journals (Sweden)

    Aral İ. OKAY

    1989-06-01

    Full Text Available Mount Honaz region in the Western Taurides is made up of superimposed several tectonic units. In the west, monotonous green metashales called the Honaz shale occur at the base of the tectonic stack. Honaz shale is tectonically overlain by weakly metamorphosed, massif white limestone, thinly bedded cherty limestone and shale which covers the Mendercs massif. Menderes massif is in turn tectonically overlain by the Sandak complex of the Lycian nappes made up of Mesozoic dolomites and limestones and ophiolite mainly of harzburgite lies oven the Sandak complex. All these tectonic units form an eastward overturned major anticline called the Honaz anticline; a pelagic sedimentary sequence of Late Cretaceous—Middle/Late Eocene age, called the Göbecik Tepe complex, occurs tectonically beneath the overturned limb of the Honaz anticline. The Göbecik Tepe complex constitutes the relative autochthonous in the region of the Mount Honaz. Different tectonic units in the Mount Honaz region show effects of Late Cretaceous, Middle Eocene and Late Eocene/Oligocene tectonics. Obduction of the ophiolite over the Sandak complex probably occurred during the Late Cretaceous, while the age of thrusting of the Sandak complex over the Menderes massif is probably Middle Eocene. Emplacement of these tectonic units over the Göbecik Tepe complex and the formation of the Honaz anticline is of Late Eocene/Oligocene age.

  9. The Atlantis Bank Gabbro Massif, SW Indian Ridge: the Largest Know Exposure of the Lower Crust in the Oceans

    Science.gov (United States)

    Dick, H. J.; Kvassnes, A. J.; Kinoshita, H.; MacLeod, C. J.; Robinson, P. T.

    2017-12-01

    thickness exist at Atlantis Bank, we can extend the conclusions derived from drilling at Hole U1473 that there is a continuum of accretionary magmatic and tectonic processes for 2.7 Myr, and a centrally located deep hole through the lower crust and mantle there will likely be representative of the 660-km2 Atlantis Bank gabbro massif as a whole.

  10. Early fracturing in argillaceous massifs and related carbonate transfer

    International Nuclear Information System (INIS)

    Beaudoin, B.; Dennebouy, S.; Parize, O.; Brulhet, J.; Trouiller, A.

    2004-01-01

    To be sure of the stability in the future of underground storage in argillaceous massifs needs to understand the present-day properties of the sediment in the light of its history. It is why early fracturing and associated carbonate transfer in shaly-marly massifs is one of the major themes of the MINANDRA Partnership (Ecole des Mines de Paris + ANDRA + some collaborators). That joint program involves tens of geo-scientists, and we would like to present here the main objects we study and the methods we apply. The base of the project is made of selected large reference-outcrops where an early fracturing is undoubtedly visible in the field. Two sets of such outcrops are presently worked in south-eastern France: - Aptian-albian marls (Marnes Bleues), at Bevons (near 04-Sisteron) and Saint-Andre de Rosans (W. of 05-Serres). - Domerian marls, at Clue du Vancon (E. of 04-Sisteron). Both are made of thick marls and intercalated limestone beds and nodules. (authors)

  11. Southwestern Power Administration Annual Report 2012

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-09-01

    Dear Secretary Moniz: I am pleased to present the financial statements and operating data for Southwestern Power Administration (Southwestern) for Fiscal Year (FY) 2012. In FY 2012, Southwestern delivered over 4.1 billion kilowatt-hours of energy to its wholesale customers in Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas, generating $195 million in revenue. In fulfilling its mission to market and reliably deliver renewable Federal hydroelectric power, Southwestern maintains 1,380 miles of high-voltage transmission lines, substations, and communications sites, contributing to the reliability of the regional and National electric grid. Southwestern also actively partners with the Department of Energy, the U.S. Army Corps of Engineers, Southwestern’s customers, and other Federal power stakeholders to most effectively balance their diverse interests with Southwestern’s mission while continuing to maximize Federal assets to repay the Federal investment in the 24 hydropower facilities within Southwestern’s marketing region. Southwestern is proud of its past successes, and we look forward to continuing to serve the Nation’s energy needs in the future. Sincerely, Christopher M. Turner Administrator

  12. Southwestern Power Administration Annual Report 2010

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-09-01

    Dear Secretary Chu: I am pleased to present the financial statements and operating data for Southwestern Power Administration (Southwestern) for Fiscal Year (FY) 2010. In FY 2010, Southwestern delivered nearly 7.6 billion kilowatt-hours of energy to its wholesale customers in Arkansas, Kansas, Louisiana, Missouri, Texas, and Oklahoma, generating $189 million in revenue. In fulfilling its mission to market and reliably deliver renewable Federal hydroelectric power, Southwestern maintains 1,380 miles of high-voltage transmission lines, substations, and communications sites, contributing to the reliability of the regional and National electric grid. Southwestern also actively partners with the Department of Energy, the U.S. Army Corps of Engineers, Southwestern’s customers, and other Federal power stakeholders to most effectively balance their diverse interests with Southwestern’s mission while continuing to maximize Federal assets to repay the Federal investment in the 24 hydropower facilities within Southwestern’s marketing region. Southwestern is proud of its past successes, and we look forward to continuing to serve the Nation’s energy needs in the future. Sincerely, Christopher M. Turner Administrator

  13. Southwestern Power Administration Annual Report 2011

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-04-01

    Dear Secretary Chu: I am pleased to present the financial statements and operating data for Southwestern Power Administration (Southwestern) for Fiscal Year (FY) 2011. In FY 2011, Southwestern delivered over 4.1 billion kilowatt-hours of energy to its wholesale customers in Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas, generating $167 million in revenue. In fulfilling its mission to market and reliably deliver renewable Federal hydroelectric power, Southwestern maintains 1,380 miles of high-voltage transmission lines, substations, and communications sites, contributing to the reliability of the regional and National electric grid. Southwestern also actively partners with the Department of Energy, the U.S. Army Corps of Engineers, Southwestern’s customers, and other Federal power stakeholders to most effectively balance their diverse interests with Southwestern’s mission while continuing to maximize Federal assets to repay the Federal investment in the 24 hydropower facilities within Southwestern’s marketing region. Southwestern is proud of its past successes, and we look forward to continuing to serve the Nation’s energy needs in the future. Sincerely, Christopher M. Turner Administrator

  14. The Alto Moxoto Terrain in Eastern Paraiba ('Caldas Brandao Massif')

    International Nuclear Information System (INIS)

    Neves, Benjamim Bley de Brito; Campos Neto, Mario da Costa; Souza, Solange Lucena de; Schmus, William Randall Van; Fernandes, Tania Maria Gomes

    2001-01-01

    The Alto Moxoto Terrane (TAM), at the east of Paraiba State is mostly composed of sheared ortho gneisses, porphyritic granodioritic gneisses and it bears an imbricated sheet of Al-rich (garnet-biotite-sillimanite) gneisses, deeply affected by migmatization phenomena. This litho-structural assemblage is drawing a regional asymmetric anti formal structure, with its axial zone running parallel to the B R-230 highway (E-W trending). It is limited in both, north (Alto Pajeu terrane) and south (Rio Capibaribe terrane) sides by important shear zones, which are feather faults connected with the development of the Pernambuco lineament, to the southwest. The adopted designation of 'terrane' is based upon its singular geological features, in terms of lithological and structural characteristics, Paleoproterozoic in age and sharp limits with the different confining terranes. TAM is here considered as a mega-fragment of the Atlantica Super continent, that was built up by the Paleoproterozoic Collage ('Transamazonian') and that was preserved in the framework of West Gondwana (Brasiliano/Pan African Collage) as a 'terrane'. This terrane shows conspicuous continuity to the far interior of the province, to the southwestern part of Pernambuco State, and so doing, it demonstrates that the former designation of 'Caldas Brandao Massif must be ruled out, as obsolete for many reasons. Geochronological determinations using Rb-Sr, Sm-Nd and U-Pb methods confirm the Paleoproterozoic age of this terrane, with the presence of some Archean protoliths as well as the various degrees of structural reworking and isotopic reseting promoted by the Brasiliano Cycle. This cycle was responsible for some intrusive granites, for most of the general geological features, like usual informal limits and even the present shape of the TAM, a typical reworked 'basement inlier'. (author)

  15. An Andean type Palaeozoic convergence in the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Schulmann, K.; Konopásek, J.; Janoušek, V.; Lexa, O.; Lardeaux, J.-M.; Edel, J.-B.; Štípská, P.; Ulrich, Stanislav

    2009-01-01

    Roč. 341, č. 2-3 (2009), s. 266-286 ISSN 1631-0713 Institutional research plan: CEZ:AV0Z30120515 Keywords : Bohemian Massif * Saxothuringian oceanic subduction * building of Variscan orogenic root system * channel flow Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.931, year: 2009

  16. New evidence of effusive and explosive volcanism in the Lower Carboniferous formations of the Moroccan Central Hercynian Massif: Geochemical data and geodynamic significance

    Science.gov (United States)

    Ntarmouchant, A.; Smaili, H.; Bento dos Santos, T.; Dahire, M.; Sabri, K.; Ribeiro, M. L.; Driouch, Y.; Santos, R.; Calvo, R.

    2016-03-01

    The Azrou-Khénifra basin, located in the SE sector of the Moroccan Central Hercynian Massif of the Western Meseta of Morocco comprises volcanic and volcanoclastic rocks where two magmatic sequences can be distinguished: i) the Dhar Lahmar Sequence, composed of Upper Visean basaltic lava flows and pyroclastic deposits; and ii) the Kef Al Asri Sequence, composed of Visean - Serpukhovian intermediate to acid rocks. A continuous spatial and temporal evolution between the two volcano-sedimentary sequences was observed during the detailed geological work performed in the studied area. Petrography and geochemical studies additionally suggest a continuous compositional evolution from the more basic magmatic rocks to the intermediate/acid rocks, which implies a cogenetic magmatic differentiation controlled by crystal fractionation (with minor crustal assimilation) of a calc-alkaline trend magmatic suite. The inferred magmatic evolution is consistent with a geodynamic environment of an orogenic zone within an active continental margin setting. This partly explosive Visean - Serpukhovian volcanism, identified for the first time in the Western Meseta of Morocco, displays very similar petrographic and geochemical characteristics to its Eastern Meseta analogues, which implies that the emplacement of these magmatic rocks must have occurred in similar collisional geodynamic settings for both major geological domains, further constraining the evolution of this major crustal segment within the Carboniferous events that shaped the Hercynian Orogeny.

  17. First data on Sm-Nd systematization of Khanka Massif metamorphic rocks, Primor'e

    International Nuclear Information System (INIS)

    Mishkin, M.A.; Khanchuk, A.I.; Zhuravlev, D.Z.; Lavrik, S.N.

    2000-01-01

    The age of the metamorphic rocks of the Khanka massif, Primor'e, is determined through the method of the Sm-Nd isotopic dating. The results of the isotopic studies on the amphibolites of the Nakhimov suite of the Khanka massif indicated that the rocks of this suite are not older than 1.7 billion years. The obtained age corresponds to the time of the amphibolite protolith formation, the source whereof is the moderately depleted mantle. The isotopic age of the amphibole and plagioclase mineral fractions constitutes 733 ± 25 mln years, which reflects the time of the Nakhimov suite rocks metamorphism [ru

  18. Palaeomagnetic constraints on the evolution of the Atlantis Massif oceanic core complex (Mid-Atlantic Ridge, 30°N)

    Science.gov (United States)

    Morris, A.; Pressling, N.; Gee, J. S.

    2012-04-01

    Oceanic core complexes expose lower crustal and upper mantle rocks on the seafloor by tectonic unroofing in the footwalls of large-slip detachment faults. They represent a fundamental component of the seafloor spreading system at slow and ultraslow axes. One of the most extensively studied oceanic core complexes is Atlantis Massif, located at 30°N at the intersection of the Atlantis Transform Fault and the Mid Atlantic Ridge (MAR). The central dome of the massif exposes the corrugated detachment fault surface and was drilled during IODP Expedition 304/305 (Hole U1309D). This sampled a 1.4 km faulted and complexly layered footwall section dominated by gabbroic lithologies with minor ultramafic rocks. Palaeomagnetic analyses demonstrate that the gabbroic sequences at Atlantis Massif carry highly stable remanent magnetizations that provide valuable information on the evolution of the section. Thermal demagnetization experiments recover high unblocking temperature components of reversed polarity (R1) throughout the gabbroic sequences. Correlation of structures observed on oriented borehole (FMS) images and those recorded on unoriented core pieces allows reorientation of R1 remanences. The mean remanence direction in true geographic coordinates constrains the tectonic rotation experienced by the Atlantis Massif footwall, indicating a 46°±6° counterclockwise around a MAR-parallel horizontal axis trending 011°±6°. The detachment fault therefore initiated at a steep dip of >50° and then rotated flexurally to its present day low angle geometry (consistent with a 'rolling-hinge' model for detachment evolution). In a number of intervals, the gabbros exhibit a complex remanence structure with the presence of additional intermediate temperature normal (N1) and lower temperature reversed (R2) polarity components, suggesting an extended period of remanence acquisition during different polarity intervals. Sharp break-points between different polarity components suggest

  19. The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

    Science.gov (United States)

    Lopez-Gamundi, O. R.; Conaghan, P. J.; Rossello, E. A.; Cobbold, P. R.

    1995-04-01

    The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m — thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early — early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana.

  20. Man-induced transformation of mountain meadow soils of Aragats mountain massif (Armenia)

    Science.gov (United States)

    Avetisyan, M. H.

    2018-01-01

    The article considers issues of degradation of mountain meadow soils of the Aragats mountain massif of the Republic of Armenia and provides the averaged research results obtained for 2013 and 2014. The present research was initiated in the frames of long-term complex investigations of agroecosystems of Armenia’s mountain massifs and covered sod soils of high mountain meadow pasturelands and meadow steppe grasslands lying on southern slope of Mt. Aragats. With a purpose of studying the peculiarities of migration and transformation of flows of major nutrients namely carbon, nitrogen, phosphorus in study mountain meadow and meadow steppe belts of the Aragats massif we investigated water migration of chemical elements and regularities of their leaching depending on different belts. Field measurement data have indicated that organic carbon and humus in a heavily grazed plot are almost twice as low as on a control site. Lysimetric data analysis has demonstrated that heavy grazing and illegal deforestation have brought to an increase in intrasoil water acidity. The results generated from this research support a conclusion that a man’s intervention has brought to disturbance of structure and nutrient and water regimes of soils and loss of significant amounts of soil nutrients throughout the studied region.

  1. Southwestern Power Administration Update, October- December 2004

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-12-01

    On October 29, 2004, Southwestern and Southwest Power Pool, Inc. (SPP) reached agreement on interim arrangements to be implemented after the October 31, 2004, expiration of the membership agreement between the two parties. According to Jim McDonald, Director of Southwestern’s Division of Customer Service, the interim agreement forged between Southwestern and SPP seeks to minimize impacts to SPP as well as to Southwestern and its customers while Southwestern and SPP work on a seams/coordination agreement to succeed the expired membership agreement.

  2. Gold in Accessory Zircon (the Kozhim Massif, Subpolar Urals)

    Science.gov (United States)

    Denisova, Yuliya; Pystin, Aleksandr

    2017-12-01

    The crystals of zircon due to their resistance to external impact of various processes can reveal information about the environment of their formation and the inclusions observed of them. Zircon contains different mineral inclusions: biotite, plagioclase, quartz, apatite, etc. However, there is no information about gold inclusions in the zircons from granites of the Sudpolar Urals. The study results of the inclusions of gold in accessory zircon of the Kozhim granitic massif are presented in this paper. The studied mineral is a dark-brown translucent short-prismatic crystal containing the inclusion of gold and the allocations of quartz. According to studies, the inclusion of gold formed during the growth of zircon and it is the gold covered with a thin film of oxide gold. It was confirmed that the crystallization of the studied zircon occurred at a temperature of 800°C and above on the stage of formation of granites of Kozhim massif. The assumption is made about the additional temperature in the course of which was caused by decreasing of temperature up to 700° C and below during postmagmatic stage.

  3. Rainwater chemistry at the summit and southern flank of the Itatiaia massif, Southeastern Brazil

    International Nuclear Information System (INIS)

    Mello, William Z. de; Almeida, Marcelo D. de

    2004-01-01

    Wet deposition and related rainwater chemistry were studied at the Itatiaia massif, on which is settled the Itatiaia National Park (INP). Samples were simultaneously collected on a weekly basis over 12 months, using automated wet and dry samplers, at the INP-Headquarters (INP-Hq; altitude=820 m) and the Itatiaia Plateau (It-Pt; altitude=2460 m). Conductivity, pH, Na + , K + , Mg 2+ , Ca 2+ , NH 4 + , Cl - , NO 3 - and SO 4 2- were determined in 36 rainwater samples. Volume-weighted mean (VWM) pH was lower at the INP-Hq (4.9) than at the It-Pt (5.3). Very strong correlation between Cl - and Na + was found for the INP-Hq (r=0.99). At the Itatiaia massif, SO 4 2- , NO 3 - , and NH 4 + comprised together about 60% of the total inorganic ions and appear to exert the major control on rainwater pH. - Rainwater chemistry at the Itatiaia massif in SE Brazil is strongly dominated by S and N inorganic species, and influenced by human activities

  4. Geochronology and geochemistry of early Paleozoic intrusive rocks from the Khanka Massif in the Russian Far East: Petrogenesis and tectonic implications

    Science.gov (United States)

    Xu, Ting; Xu, Wen-Liang; Wang, Feng; Ge, Wen-Chun; Sorokin, A. A.

    2018-02-01

    This paper presents new geochronological and geochemical data for early Paleozoic intrusive rocks from the Khanka Massif in the Russian Far East, with the aim of elucidating the Paleozoic evolution and tectonic attributes of the Khanka Massif. New U-Pb zircon data indicate that early Paleozoic magmatism within the Khanka Massif can be subdivided into at least four stages: 502, 492, 462-445, and 430 Ma. The 502 Ma pyroxene diorites contain 58.28-59.64 wt% SiO2, 2.84-3.69 wt% MgO, and relatively high Cr and Ni contents. Negative εHf(t) values (- 1.8 to - 0.4), along with other geochemical data, indicate that the primary magma was derived from partial melting of mafic lower crust with the addition of mantle material. The 492 Ma syenogranites have high SiO2 and K2O contents, and show positive Eu anomalies, indicating the primary magma was generated by partial melting of lower crust at relatively low pressure. The 445 Ma Na-rich trondhjemites display high Sr/Y ratios and positive εHf(t) values (+ 1.8 to + 3.9), indicating the primary magma was generated by partial melting of thickened hydrous mafic crust. The 430 Ma granitoids have high SiO2 and K2O contents, zircon εHf(t) values of - 5.4 to + 5.8, and two-stage model ages of 1757-1045 Ma, suggesting the primary magma was produced by partial melting of heterogeneous Proterozoic lower crustal material. The geochemistry of these early Paleozoic intrusive assemblages indicates their formation in an active continental margin setting associated with the subduction of a paleo-oceanic plate beneath the Khanka Massif. The εHf(t) values show an increasingly negative trend with increasing latitude, revealing a lateral heterogeneity of the lower crust beneath the Khanka Massif. Regional comparisons of the magmatic events indicate that the Khanka Massif in the Russian Far East has a tectonic affinity to the Songnen-Zhangguangcai Range Massif rather than the adjacent Jiamusi Massif.

  5. Southwestern Power Administration annual site environmental report CY 1997

    International Nuclear Information System (INIS)

    1998-01-01

    This report provides a synopsis of Southwestern Power Administration's (Southwestern's) effectiveness in managing its operations in an environmentally responsible manner. In CY 1997, the Office of Environmental, Safety, and Health was reorganized and incorporated into the Division of Acquisition and Property. The Division of Acquisition, Property, and Environmental Management maintains responsibility for development, oversight, and implementation of environmental programs. Senior Management at Southwestern has taken actions to increase environmental awareness throughout the organization. During CY 1997, (Southwestern) was not involved in any known programs or activities that had adverse impacts on the environment. The 1997 Environmental Appraisal, a portion of Southwestern's Self-Assessment and Appraisal Program, indicated approximately 90% compliance with Southwestern's written environmental programs. Southwestern continued to function throughout CY 1997 in an operations and maintenance posture with minor substation projects

  6. Nematocarcinus Milne Edwards, 1881 (Crustacea, Decapoda) from Southwestern Atlantic, including the Southern Mid-Atlantic Ridge area.

    Science.gov (United States)

    Cardoso, Irene A; Burukovsky, Rudolf N

    2014-11-26

    The deep sea shrimp genus Nematocarcinus Milne Edwards, 1881 includes 47 species, ten of them have been recorded from the Atlantic Ocean. Herein, material sampled during three scientific projects (REVIZEE Central Fishery project; Campos Basin Deep Sea Environmental Project; Evaluation of Environmental Heterogeneity in the Campos Basin) made in the Southwestern Atlantic, off Brazil, is examined. In addition, material sampled from the South Mid Atlantic Ridge (MAR-ECO Project) was also examined. Four species are recorded for the first time to the southwestern Atlantic Ocean including Mid Atlantic Ridge area: Nematocarcinus faxoni Burukovsky, 2001; N. gracilipes Filhol, 1884; N. rotundus Crosnier & Forest, 1973 and N. tenuipes Spence-Bate, 1888.

  7. Influence of geotechnical properties of the rocks of massif Vajarska on the technology of used blasting operations

    Directory of Open Access Journals (Sweden)

    Oreská ¼udmila

    1997-12-01

    Full Text Available Geotechnical properties of a rock massif have a decisive influence on the technology of blasting operations and on the resulting fragmentation of the blast. Parameters of the blasting operations were given for the limestone deposit Vajarska on the base of knowledge about fractures of the massif Vajarska. The computer programm is used to choice new para-meters for the blasting operations in HIROCEM, a.s., Rohožník.

  8. From ocean depths to mountain tops: uplift of the Troodos Massif (Cyprus) constrained by (U-Th)/He thermochronology and geomorphic analysis

    Science.gov (United States)

    Morag, N.; Haviv, I.; Katzir, Y.

    2013-12-01

    The Troodos Massif of Cyprus, rising to nearly 2000 meters above sea level, encompasses one of the world's classic ophiolites. Following its formation at a seafloor spreading center in Late Cretaceous times, this slice of the NeoTethyan oceanic lithosphere was uplifted and eventually exposed on mountain tops during the Neogene. The final uplift and exhumation of the Troodos was previously assigned to Pleistocene age by observations in the circum-Troodos sedimentary strata. However, quantitative thermochronological and geomorphological data from the Massif itself were not available. Here we use apatite (U-Th)/He low-temperature thermochronology complemented by zircon (U-Th)/He and apatite fission track data, and combined with geomorphic analysis to constrain the exhumation and uplift history of the Troodos ophiolite. Apatite (U-Th)/He ages vary with depth from ~ 22 Ma at the top of the Gabbro sequence to ~ 6 Ma at the bottom of the sequence. The deepest sample from a Gabbro pegmatitic dyke intruding the ultramafic sequence yielded an age of ~ 3 Ma. Thermal modeling of apatite (U-Th)/He and fission track data delineates Plio - Pleistocene initiation of rapid uplift and exhumation of the Troodos ophiolite. The estimated cumulative exhumation since its initiation is 2-3 km. No evidence was found for significant uplift of the central Troodos area prior to that time. The geomorphic analysis delineates a bull's-eye zone at the center of the Troodos Massif, where local relief and channel steepness index are highest. The boundaries of this zone roughly correspond with the Mt. Olympus mantle outcrop and suggest recent, differential uplift of this zone relative to its surroundings. The most likely mechanism, which could drive such a focused bull's-eye uplift pattern is hydration of ultramafic rocks (serpentinization) leading to a decrease in rock density and subsequent diapiric uplift of the serpentinized lithospheric mantle.

  9. N-S crustal shear system in the Bundelkhand massif: a unique ...

    Indian Academy of Sciences (India)

    56

    In the light of our detailed geological studies of the massif (Singh and Bhattacharya,. 2010 .... relations with, and displace, the earlier shear systems, i.e. BS1, BS2 and BS3 (Fig. 3D), (3) ..... and shear zone patterns: The South Indian case. Jour.

  10. Neogene Uplift and Exhumation of Plutonic Bodies in the Beni Bou Ifrour Massif (Nador, northeastern Morocco)

    Science.gov (United States)

    Lebret, Noëmie; Jolivet, Laurent; Branquet, Yannick; Bourdier, Jean-Louis; Jolivet, Marc; Marcoux, Eric

    2013-04-01

    In Neogene times, the whole Mediterranean Sea was the center of an intense magmatic activity. This post-collisional magmatism produced a large amount of volcanic edifices through the Alpine belts, together with some intrusives. These plutonic bodies can be associated with skarn-type mineralization, well-known in Elba Island or Serifos Island (Cyclades), where they are generally exhumed by detachment faults. In Morocco, the plutons hosted by the Beni Bou Ifrour massif are connected to the biggest skarn-type iron concentrations of the country (production > 60 Mt, reserves ≈ 25 Mt). The purpose of this work is to explain the late uplift of this massif and subsequent exhumation of the intrusives. As a final product of the Africa-Eurasia plate convergence since ca. 70 Ma, the Rif Mountains constitute the westernmost segment of the Mediterranean Alpine belts. In the oriental part of this range, volcanic summits and Paleozoic to Mesozoic massifs outcrop in the surrounding Mio-Pliocene plains. The Beni Bou Ifrour massif, in the Nador province, consists in a dome-shaped folded Mesozoic series (Domerian to Barremian) affected by a slight epizonal regional metamorphism (ca. 14-12 Ma), dislocated by Neogene NE-SW faults and eventually sealed by upper Miocene transgressive sediments. The hosted intrusives (7.58 ± 0.03 Ma; Duggen et al., 2005) are the plutonic equivalents to the potassic calc-alkaline lavas (andesites mainly) from the surrounding "satellite" volcanic massifs. They turn out to stand in higher topographic position than the younger shoshonitic lavas of the neighboring Gourougou stratovolcano (6.12 ± 0.01 Ma; Duggen et al., 2005). Previous studies have attributed this uplift to the action of normal faults (pull-apart basins; Guillemin & Houzay, 1982), thrusting (Kerchaoui, 1985; 1995) or even of a caldeira resurgence (El Bakkali, 1995). To discriminate against those exhumation mechanisms, field work has been performed, coming along with new cross-sections to

  11. New data for paleoprotherozoic PGE-bearing anorthosite of Kandalaksha massif (Baltic shield): U-Pb and Sm-Nd ages

    Science.gov (United States)

    Steshenko, Ekaterina; Bayanova, Tamara; Serov, Pavel

    2015-04-01

    The aims of this researches were to study the isotope U-Pb age of zircon and rutile and Sm-Nd (rock forming and sulphide minerals) on Kandalaksha anorthosite massif due to study of polimetamorphic history. In marginal zone firstly have been obtained the presence of sulphide mineralization with PGE (Chashchin, Petrov , 2013). Kandalaksha massif is located in the N-E part of Baltic shield and consists of three parts. Marginal zone (mesocratic metanorite) lies at the base of the massif. Main zone is composed of leucocratic metagabbro. The upper zone is alteration of mataanorthosite and leucocratic metagabbro. All rocks were subjected to granulate polymetamorphism. Two fractions of single grains from anorthosite of the massif gave precise U-Pb age, which is equal to 2450± 3 Ma. Leucocratic gabbro-norite were dated by U-Pb method, with age up to 2230 ± 10 Ma. This age reflects the time of granulite metamorphism according to data of (Mitrofanov, Nirovich, 2003). Two fractions of rutile have been analyzed by U-Pb method and reflect age of 1700 ± 10 Ma. It is known that the closure temperature of U-Pb system rutile is 400-450 ° C (Mezger et.al., 1989), thus cooling processes of massif rocks to these temperatures was about 1.7 Ga. These data reflect one of the stages of metamorphic alteration of the massif. Three stages of metamorphism are distinguished by Sm-Nd method. Isotope Sm-Nd dating on Cpx-WR line gives the age of 2311 Ma which suggested of high pressure granulite metamorphism. Moreover Cpx-Pl line reflect the age 1908 Ma of low pressure granulite metamorphism. Also two-points (Grt-Rt) Sm-Nd isochrone yield the age 1687 Ma of the last metamorphic alterations in Kandalaksha anorthosite massif. Model Sm-Nd age of the leucocratic gabbro-norite is 2796 Ma with positive ɛNd (+0.32). It means that the source of gabbro-norite was mantle reservoir. All investigations are devoted to memory of academician PAS F. MItrofanov which was a leader of scientific school for

  12. N-S crustal shear system in the Bundelkhand massif: A unique crustal evolution signature in the northern Indian peninsula

    Science.gov (United States)

    Singh, S. P.; Bhattacharya, A. R.

    2017-12-01

    The Bundelkhand massif, located in the northern part of the Indian shield, is a poly-deformed and poly-metamorphic terrain. This paper reports a new shear system developed throughout the massif in the form of N-S trending quartz veins that are sometimes quartzo-feldspathic and rarely granitic in composition. The veins are vertical and commonly occur in conjugate sets. This tectono-magmatic event appears to represent the youngest shear system of the massif as it cross-cuts all the earlier shear systems (E-W, NE-SE and NW-SE). Emplacement of this N-S vein system may have taken place due to extensional processes that developed some cracks along which siliceous magma was vertically emplaced. The complete absence of signature of the N-S event from the surrounding sedimentary cover of Vindhyan Supergroup, Bijawar and Gwalior Groups suggests that this shear system is pre-tectonic to the nearly E-W trending passive basins developed at the margins of the Bundelkhand craton. Further, several workers have considered the Bundelkhand massif as a part of the Aravalli craton. However, due to the absence of N-S, as well as the other (i.e., E-W, NW-SE and NW-SE), tectonic fabrics of the Bundelkhand massif in other cratons of the Peninsular India, and vice versa, makes the Bundelkhand block a separate and unique craton of its own and is not part of the Aravalli craton.

  13. Geologic-geochemical characteristics of Guidong granitic massif and recognition of geo-tectonic environment at the time of its emplacement

    Energy Technology Data Exchange (ETDEWEB)

    Jianhong, Li; Shanyuan, Wei; Mingyue, Feng [Beijing Research Inst. of Uranium Geology, Beijing (China); Liang, Liang [East China Inst. of Technology, Fuzhou (China)

    2004-11-01

    Based on the study of geologic characteristics, such as mineralogic assemblage, structural and textural features of granite of Guidong granitic massif, and by using petrochemical, trace-element and isotopic data, and some petrochemical, trace-element and isotopic diagrams widely applied to the identification of geo-tectonic environments, authors recognize that Guidong granitic massif was emplaced in post-orogenic collision environment. (authors)

  14. Felsic granulite with layers of eclogite facies rocks in the Bohemian Massif; did they share a common metamorphic history?

    Science.gov (United States)

    Jedlicka, Radim; Faryad, Shah Wali

    2017-08-01

    High pressure granulite and granulite gneiss from the Rychleby Mountains in the East Sudetes form an approximately 7 km long and 0.8 km wide body, which is enclosed by amphibolite facies orthogneiss with a steep foliation. Well preserved felsic granulite is located in the central part of the body, where several small bodies of mafic granulite are also present. In comparison to other high pressure granulites in the Bohemian Massif, which show strong mineral and textural re-equilibration under granulite facies conditions, the mafic granulite samples preserve eclogite facies minerals (garnet, omphacite, kyanite, rutile and phengite) and their field and textural relations indicate that both mafic and felsic granulites shared common metamorphic history during prograde eclogite facies and subsequent granulite facies events. Garnet from both granulite varieties shows prograde compositional zoning and contains inclusions of phengite. Yttrium and REEs in garnet show typical bell-shaped distributions with no annular peaks near the grain rims. Investigation of major and trace elements zoning, including REEs distribution in garnet, was combined with thermodynamic modelling to constrain the early eclogite facies metamorphism and to estimate pressure-temperature conditions of the subsequent granulite facies overprint. The first (U)HP metamorphism occurred along a low geothermal gradient in a subduction-related environment from its initial stage at 0.8 GPa/460 °C and reached pressures up to 2.5 GPa at 550 °C. The subsequent granulite facies overprint (1.6-1.8 GPa/800-880 °C) affected the rocks only partially; by replacement of omphacite into diopside + plagioclase symplectite and by compositional modification of garnet rims. The mineral textures and the preservation of the eclogite facies prograde compositional zoning in garnet cores confirm that the granulite facies overprint was either too short or too faint to cause recrystallisation and homogenisation of the eclogite

  15. Massification and Diversity of Higher Education Systems: Interplay of Complex Dimensions

    Science.gov (United States)

    Guri-Rosenblit, Sarah; Sebkova, Helena; Teichler, Ulrich

    2007-01-01

    This paper provides a synthetic overview of the complex dimensions that shape the interrelations between the massification of higher education systems and their structure and composition. Many higher education systems worldwide expanded extensively in the last decades, and have undergone wide and deep structural changes. Most notably, the…

  16. Datation U_Pb : âge de mise en place du magmatisme bimodal des Jebilet centrales (chaîne Varisque, Maroc). Implications géodynamiquesU_Pb dating: emplacement age of the bimodal magmatism of central Jebilet (Variscan Belt, Morocco). Geodynamic implications

    Science.gov (United States)

    Essaifi, Abderrahim; Potrel, Alain; Capdevila, Ramon; Lagarde, Jean-Louis

    2003-01-01

    The bimodal magmatism of central Jebilet is dated to 330.5 +0.68-0.83 Ma by UPb dating on zircons. This age, similar to that of the syntectonic Jebilet cordierite-bearing granitoids, corresponds to the age of the local major tectonometamorphic event. The syntectonic plutonism of the Jebilet massif, composed of tholeiitic, alkaline, and peraluminous calc-alkaline series, is variegated. Magmas emplacement was favoured by the local extension induced by the motion along the western boundary of the Carboniferous basins of the Moroccan Meseta. The Jebilet massif exemplifies the activation of various magmas sources during an episode of continental convergence and crustal wrenching.

  17. Crystal structure of modular sodium-rich and low-iron eudialyte from Lovozero alkaline massif

    Energy Technology Data Exchange (ETDEWEB)

    Rozenberg, K. A.; Rastsvetaeva, R. K., E-mail: rast@ns.crys.ras.ru; Aksenov, S. M. [Federal Scientific Research Center “Crystallography and Photonics”, Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2016-09-15

    The structure of the sodium-rich representative of the eudialyte group found by A.P. Khomyakov at the Lovozero massif (Kola Peninsula) is studied by X-ray diffraction. The trigonal cell parameters are: a = 14.2032(1) and c = 60.612(1) Å, V = 10589.13 Å3, space group R3m. The structure is refined to the final R = 5.0% in the anisotropic approximation of atomic displacement parameters using 3742|F| > 3σ(F). The idealized formula (Z = 3) is Na{sub 37}Ca{sub 10}Mn{sub 2}FeZr{sub 6}Si{sub 50}(Ti, Nb){sub 2}O{sub 144}(OH){sub 5}Cl{sub 3} · H{sub 2}O. Like other 24-layer minerals of the eudialyte group, this mineral has a modular structure. Its structure contains two modules, namely, “alluaivite” (with an admixture of “eudialyte”) and “kentbrooksite,” called according to the main structural fragments of alluaivite, eudialyte, and kentbrooksite. The mineral found at the Lovozero alkaline massif shows some chemical and symmetry-structural distinctions from the close-in-composition labyrinthite modular mineral from the Khibiny massif. The difference between the minerals stems from different geochemical conditions of mineral formation in the two regions.

  18. Cancer mortality and radioactive fallout in southwestern Utah

    International Nuclear Information System (INIS)

    Machado, S.G.; Land, C.E.; McKay, F.W.

    1987-01-01

    Cancer mortality was compared between a three-county region in southwestern Utah and the remainder of Utah in an investigation of reported excess cancer risks associated with residence in southwestern Utah during the period of above-ground nuclear tests at the Nevada Test Site. Because most of the fallout in southwestern Utah was deposited during 1953-1957, comparisons were limited to persons born before 1958, and deaths from leukemia and bone cancer during 1955-1980 and from other cancers during 1964-1980. There was no excess risk of cancer mortality in southwestern Utah, for single or grouped sites, with the single exception of leukemia which showed statistically significant odds ratios of 1.45 based on 62 deaths at all ages, and 2.84 based on nine deaths at ages 0-14. The finding for childhood leukemia was based on different time periods and geographic comparisons from those of two earlier studies in which no such excess was found. Mortality from all cancer sites combined was significantly lower in southwestern Utah than in the remainder of the state, even after adjustment for the higher proportion of (lower risk) Mormons in southwestern Utah. The present results, including the positive association for leukemia, are inconsistent with the high excess risks reported by Johnson (JAMA 1984;251:230-6) based on an interview survey of cancer incidence among long-term Mormon residents of southwestern Utah

  19. HT-LP thermometamorphism modelling : Agly massif, French Pyrenees.

    Science.gov (United States)

    Tournaire Guille, Baptiste; Pascal, Marie-Lola; Lejeune, Anne-Marie; Annen, Catherine

    2017-04-01

    Owing to the strongly anomalous thermal gradients implied, HT-LP metamorphism is a worldwide type of processes in which magma emplacement and solidification at relatively high levels in the crust must be considered as a potentially major heat source. Thermal modelling (e.g. Annen et al. 2005) is an appropriate tool for constraining the part played by such processes in practical cases of thermometamorphism. We study the Agly massif, an exhumed part of middle crust from the Variscan belt in the French Pyrenees. This massif is a classical example of HT-LP metamorphism (Vielzeuf 1996), composed of a metasedimentary cover, mainly micaschists aged from upper Cambrian to Devonian, unconformably overlying an older basement of para- and orthogneisses. The Variscan metamorphic facies extend from greenschists, in the upper part of the cover, to granulites in the basement (Fonteilles 1976). The apparent geotherm of about 110°/km in the metasedimentary cover (amphibolite and greenschist facies) has given way to contrasting interpretations. Magmatic activity partly synchronous with and probably related to the Variscan thermometamorphism is observed at the outcropping level as at least 4 magmatic bodies of mantle origin (Touil 1994), of Stephanian age, including granodiorites and subordinate diorites and gabbros. Recent U/Pb datations on zircons (Tournaire-Guille et al., in prep) also reveal the presence of lower Cambrian magmatism in the gneisses, therefore confirming their interpretation as a pre-Variscan basement. The location (depth), volume (thickness), temperature (composition) and timing of magma emplacement are the parameters controlling the thermal effect to be modelled with a Matlab® code (Annen et al. 2005). In order to constrain these parameters, we have updated the lithostratigraphy and the PT conditions of the Variscan metamorphism in the Agly area. Mineralogic and petrologic data exploited in thermobarometric analyses compared with thermodynamic PerpleX modelling

  20. Interaction between central volcanoes and regional tectonics along divergent plate boundaries: Askja, Iceland

    Science.gov (United States)

    Trippanera, Daniele; Ruch, Joël; Acocella, Valerio; Thordarson, Thor; Urbani, Stefano

    2018-01-01

    Activity within magmatic divergent plate boundaries (MDPB) focuses along both regional fissure swarms and central volcanoes. An ideal place to investigate their mutual relationship is the Askja central volcano in Iceland. Askja consists of three nested calderas (namely Kollur, Askja and Öskjuvatn) located within a hyaloclastite massif along the NNE-SSW trending Icelandic MDPB. We performed an extensive field-based structural analysis supported by a remote sensing study of tectonic and volcanic features of Askja's calderas and of the eastern flank of the hyaloclastite massif. In the massif, volcano-tectonic structures trend N 10° E to N 40° E, but they vary around the Askja caldera being both parallel to the caldera rim and cross-cutting on the Western side. Structural trends around the Öskjuvatn caldera are typically rim parallel. Volcanic vents and dikes are preferentially distributed along the caldera ring faults; however, they follow the NNE-SSW regional structures when located outside the calderas. Our results highlight that the Askja volcano displays a balanced amount of regional (fissure-swarm related) and local (shallow-magma-chamber related) tectonic structures along with a mutual interaction among these. This is different from Krafla volcano (to the north of Askja) dominated by regional structures and Grímsvötn (to the South) dominated by local structures. Therefore, Askja represents an intermediate tectono-magmatic setting for volcanoes located in a slow divergent plate boundary. This is also likely in accordance with a northward increase in the spreading rate along the Icelandic MDPB.

  1. Interaction between central volcanoes and regional tectonics along divergent plate boundaries: Askja, Iceland

    KAUST Repository

    Trippanera, Daniele

    2017-12-04

    Activity within magmatic divergent plate boundaries (MDPB) focuses along both regional fissure swarms and central volcanoes. An ideal place to investigate their mutual relationship is the Askja central volcano in Iceland. Askja consists of three nested calderas (namely Kollur, Askja and Öskjuvatn) located within a hyaloclastite massif along the NNE-SSW trending Icelandic MDPB. We performed an extensive field-based structural analysis supported by a remote sensing study of tectonic and volcanic features of Askja’s calderas and of the eastern flank of the hyaloclastite massif. In the massif, volcano-tectonic structures trend N 10° E to N 40° E, but they vary around the Askja caldera being both parallel to the caldera rim and cross-cutting on the Western side. Structural trends around the Öskjuvatn caldera are typically rim parallel. Volcanic vents and dikes are preferentially distributed along the caldera ring faults; however, they follow the NNE-SSW regional structures when located outside the calderas. Our results highlight that the Askja volcano displays a balanced amount of regional (fissure-swarm related) and local (shallow-magma-chamber related) tectonic structures along with a mutual interaction among these. This is different from Krafla volcano (to the north of Askja) dominated by regional structures and Grímsvötn (to the South) dominated by local structures. Therefore, Askja represents an intermediate tectono-magmatic setting for volcanoes located in a slow divergent plate boundary. This is also likely in accordance with a northward increase in the spreading rate along the Icelandic MDPB.

  2. Musa massif: mapping, petrology and petrochemical, Rio Maria, SE from Para State

    International Nuclear Information System (INIS)

    Gastal, M.C.P.

    1987-01-01

    The petrological, geochemical and geochronological studies allow some insight on the genesis and evolution of the Musa Massif. The different facies of the granitic body are cogenetic, although each of these facies presents some peculiarities in its genesis and evolution. These data suggests that the granite magma evolution was complex or, alternatively, that the facies were generated by liquids derived from different sources. A model of magmatic emplacement, genesis and differentiation is proposed and discussed. The granitic facies show a calc-alkaline compositions, exhibiting strong analogies with cordilleran granites or magnetite granites. An age of 1692 +- 11 Ma (Rb/Sr) with IR of 0,70777 +- 0,00023 was obtained for different facies of Massif. A preliminary attempt to individualize geochronology the principal facies was done and showed that there is a coincidence between the ages and the emplacement sequence of these facies of the pluton. (author)

  3. Au-As (lead) vein mineralizations of the Cevennes and Chataigneraie regions (French Massif Central). Isotopic characterization (Pb). Mineralizing role of granites in the setting up of these mineralizations

    International Nuclear Information System (INIS)

    Havard, M.L.

    1997-06-01

    This work has been carried out in the Frame of the national program 'Geofrance 3D' jointly organized by the French office for geologic and mining researches (BRGM), and the CNRS-INSU/DSPT3. Its aim is the study of the formation of gold-bearing mineralizations of the Variscan chain in the Cevennes and Chataigneraie regions (French Massif Central). In the Cevennes region, the gold-bearing veins are linked with the intrusion of the late-tectonic granodioritic plutons. The aim of this study is to determine the chronology of the mineralizing episodes and to analyze the relationship between the metal concentrates and the setting up of the granites. In the Chataigneraie region, the granites are intrusive in ortho- and para-gneiss series. The hydrothermal activity associated with the contact metamorphism should be responsible for the deposition of gold-bearing wolfram mineralization. The geochemistry of lead isotopes is used to determine the origin of metals in the sulfide mineralizations. The scanning electron microscopy (SEM) is used for the visualization of the microstructure heterogeneities of the minerals and for the quantitative chemical analysis of their successive para-geneses. The comparison between the results obtained in both regions allows to make a difference between their relative degree of erosion and their gold potentialities. (J.S.)

  4. Status, ecology, and conservation of the southwestern willow flycatcher

    Science.gov (United States)

    Deborah M. Finch; Scott H. Stoleson

    2000-01-01

    This publication was prepared in response to a need expressed by southwestern agencies and organizations for a comprehensive assessment of the population status, history, biology, ecology, habitats, threats, and conservation of the southwestern willow flycatcher (Empidonax traillii extimus). The southwestern willow flycatcher was federally listed as...

  5. Assessment of flora condition and transformation extent at the Degelen mountain massif

    International Nuclear Information System (INIS)

    Tuleubaev, B.A.; Sejsebaev, A.T.; Sultanova, B.M.; Dzhanin, B.T.

    2000-01-01

    The article describes current condition of vegetation at the Degelen mountain massif and assessment of vegetation disturbance in areas of underground nuclear testing. It also presents results of studying flora transformation, species and cinotic composition, structural and spatial distribution within the Degelen technical site. (author)

  6. Petrology of Ortsog-Uul peridotite-gabbro massif in Western Mongolia

    Science.gov (United States)

    Shapovalova, M.; Tolstykh, N.; Shelepaev, R.; Cherdantseva, M.

    2017-12-01

    The Ortsog-Uul mafic-ultramafic massif of Western Mongolia is located in a tectonic block with overturned bedding. The massif hosts two intrusions: a rhythmically-layered peridotite-gabbro association (Intrusion 1) and massive Bt-bearing amphibole-olivine gabbro (Intrusion 2). Intrusions 1 and 2 have different petrology features. Early Intrusion 1 (278±2.5Ma) is characterized by lower concentrations of alkalis, titanium and phosphorus than late Intrusion 2 (272±2Ma). The chondrite-normalized REE and primitive mantle-normalized rare elements patterns of Ortsog-Uul intrusions have similar curves of elements distribution. However, Intrusion 2 is characterized higher contents of REE and rare elements. High concentrations of incompatible elements are indicative of strong fractionation process. It has been suggested that Intrusions 1 and 2 derived from compositionally different parental melts. Model calculations (COMAGMAT-3.57) show that parental melts of two intrusions were close to high-Mg picrobasaltic magmas. The concentration of MgO in melt is 16.21 (Intrusion 1) and 16.17 (Intrusion 2). Isotopic data of Ortsog-Uul magmatic rocks exhibit different values of εNd (positive and negative) for Intrusion 1 and 2, respectively.

  7. Southwestern Power Administration site environmental report for calendar year 1993

    International Nuclear Information System (INIS)

    1994-01-01

    During CY 93, Southwestern was not involved in any programs that had a direct effect on the environment, involving endangered species, protection of wetlands, or increased electromagnetic radiation. Southwestern continued to function throughout the year in an operations and maintenance posture with minor substation projects. Southwestern received an environmental management audit by the Department of Energy's Office of Environmental Audit (EH-24), during CY 1992. The purpose of the audit was to give Southwestern, DOE headquarters, and the Secretary an indication of the status of Southwestern management's effectiveness in discharging its duties in an environmentally responsible manner. The audit identified 17 findings. An action plan was developed and remediation of the findings has been accomplished. Several strengths were identified during the audit with regard to the environmental programs at Southwestern. Most importantly, senior management at Southwestern has taken actions to increase environmental awareness throughout the organization which is evidenced by the creation of the Environmental, Safety, Health, and Security Office

  8. Paleocene-Eocene Sediments Interbedded With Volcanics Within the Lycian Nappes: Faralya Formation

    Directory of Open Access Journals (Sweden)

    Mustafa Şenel

    1991-06-01

    Full Text Available The presumably allochthonous structural units in the Southwestern Turkey between the Menderes massif and Beydağları autochthon are known as the Lycian nappes. Some of these units particularly beneath the ophiolite nappe end up with the Faralya formation of Paleocene-Lutetian age. The striking feature of this formation which includes micrite, clayey micrite, claystone, sandstone and conglomerate, is the presence of basic volcanite interbeds of Eocene age, This volcanite bearing formation exhibits a strong similarity to those of the other formations in Southwestern Turkey most of which include similar basic volcanites. Eocene basic volcanites are also known in the Akseki autochthon to the south of Seydişehir (Geyikdağ unit in broad sense. Similar extensive lateral movements (Eocene mountain building processes developed over the Faralya formation are seen over the volcanite bearing formations to the south of Menderes massif as well as to the north of Isparta angle and the Akseki autochthon. These features indicate that the area between the Menderes massif and Akseki autochthon (Geyikdağ unit reflects common basinal characters in terms of depositional conditions, volcanism and the traces of Eocene mountain building process.

  9. Post-wildfire recovery of riparian vegetation during a period of water scarcity in the southwestern USA

    Science.gov (United States)

    D. Max Smith; Deborah M. Finch; Christian Gunning; Roy Jemison; Jeffrey F. Kelly

    2009-01-01

    Wildland fires occur with increasing frequency in southwestern riparian forests, yet little is known about the effects of fire on populations of native and exotic vegetation. From 2003 to 2006, we monitored recovering woody vegetation in wildfire sites in the bosque (riparian forest) along the Middle Rio Grande of central New Mexico, USA. To examine recovery potential...

  10. Epidemiology of hepatitis B virus infection in first-time blood donors in the southwestern region of Goiás, central Brazil

    Directory of Open Access Journals (Sweden)

    Giulena Rosa Leite Cardoso dos Anjos

    2011-02-01

    Full Text Available INTRODUCTION: Little is known about the epidemiology of hepatitis B virus (HBV infection in populations from inner cities, especially in Central Brazil. Thus the objective of this study was to estimate the prevalence of HBV infection, and to analyze the factors associated with HBV infection, in a population of first-time blood donors in the southwestern region of Goiás, Central Brazil. METHODS: A total of 984 individuals were interviewed and gave blood samples to detect serological markers of HBV (HBsAg, anti-HBs, and anti-HBc by enzyme linked immunosorbent assays. RESULTS: An overall prevalence of 6.9% was found for HBV, with constituent prevalence rates of 3.6% and 11.6%, in subjects classified as fit and unfit to donate blood according the epidemiological screening, respectively. Only three individuals were positive for anti-HBs alone, suggesting previous vaccination against HBV. The variables of prior blood transfusion (OR = 2.3, tattoo/piercing (OR = 2.1, illicit drug use (OR = 2.3, sex with a partner with hepatitis (OR = 14.7, and history of sexually transmitted diseases (OR = 2.9 were independently associated with HBV-positivity. These data suggested a low endemicity of hepatitis B in the studied population. CONCLUSION: The findings of low hepatitis B immunization coverage and the association of hepatitis B with risky behavior highlight that there is a need to intensify hepatitis B prevention programs in the southwest region of Goiás.

  11. Expedition 357 Preliminary Report: Atlantis Massif Serpentinization and Life

    OpenAIRE

    Früh-Green, GL; Orcutt, BN; Green, S; Cotterill, C; McCaig, AM; Expedition 357 Scientists,

    2016-01-01

    International Ocean Discovery Program (IODP) Expedition 357 successfully cored an east–west transect across the southern wall of Atlantis Massif on the western flank of the Mid-Atlantic Ridge to study the links between serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. The primary goals of this expedition were to (1) examine the role of serpent...

  12. The Massification of Higher Education in the UK: Aspects of Service Quality

    Science.gov (United States)

    Giannakis, Mihalis; Bullivant, Nicola

    2016-01-01

    This article explores several aspects of service quality for the provision of higher education. Alongside the trend of the massification of higher education over the past two decades, higher education institutions are required to review quality across a range of outputs, besides teaching and learning. The study was undertaken within the…

  13. Middle and Late Pleistocene glaciations in the southwestern Pamir and their effects on topography [Topography of the SW Pamir shaped by middle-late Pleistocene glaciation

    International Nuclear Information System (INIS)

    Stübner, Konstanze; Grin, Elena; Hidy, Alan J.; Schaller, Mirjam; Gold, Ryan D.

    2017-01-01

    Glacial chronologies provide insight into the evolution of paleo-landscapes, paleoclimate, topography, and the erosion processes that shape mountain ranges. In the Pamir of Central Asia, glacial morphologies and deposits indicate extensive past glaciations, whose timing and extent remain poorly constrained. Geomorphic data and 15 new "1"0Be exposure ages from moraine boulders and roches moutonnées in the southwestern Pamir document multiple Pleistocene glacial stages. The oldest exposure ages, View the MathML source113 ± 10ka, underestimate the age of the earliest preserved glacial advance and imply that the modern relief of the southwestern Pamir (peaks at ~5000–6000 m a.s.l.; valleys at ~2000–3000 m a.s.l.) already existed in the late Middle Pleistocene. Younger exposure ages (~40–80 ka, ~30 ka) complement the existing Central Asian glacial chronology and reflect successively less extensive Late Pleistocene glaciations. The topography of the Pamir and the glacial chronologies suggest that, in the Middle Pleistocene, an ice cap or ice field occupied the eastern Pamir high-altitude plateau, whereas westward flowing valley glaciers incised the southwestern Pamir. Since the Late Pleistocene deglaciation, the rivers of the southwestern Pamir adjusted to the glacially shaped landscape. As a result, localized rapid fluvial incision and drainage network reorganization reflect the transient nature of the deglaciated landscape.

  14. Environmental characterization of lake ecosystems located in Serbo Macedonian massif (FYRM)

    OpenAIRE

    Dolenec, Tadej; Serafimovski, Todor; Lojen, Sonja; Dolenec, Matej; Tasev, Goran; Kramar, Sabina; Rogan Šmuc, Nastja; Vrhovnik, Petra

    2015-01-01

    This mineralogical, geochemical and isotopic characteristics of recent lacustrine sediments, of Anodonta cygnea shells and of fish species Rutilus rutilus dojranensis from the Lake Dojran (FY Republic of Macedonia, southern part of the Serbo-Macedonian Massif (SMM)), which provide indirect evidence regarding biomineralization and calcification processes as well as various geological problems. Environmental pollution can seriously impair physiological functions such as the secre...

  15. Post-Hercynian subvolcanic magmatism in the Serre Massif (Central-Southern Calabria, Italy)

    Science.gov (United States)

    Romano, V.; Cirrincione, R.; Fiannacca, P.; Mazzoleni, P.; Tranchina, A.

    2009-04-01

    In the Serre Massif (Central-Southern Calabria, Italy) dykes and subvolcanic bodies intrude diffusively both Hercynian metamorphic rocks and late-Hercynian granitoids. They range in composition from basaltic andesites to dacite-rhyodacites and can be ascribed to the extensive magmatic activity that affects the entire Hercynian orogenic belt in late Paleozoic - early Mesozoic time. The geodinamic framework of the magmatic activity is still matter of debate, nevertheless most authors agree in correlating magmatism both to the late-orogenic collapse of the Hercynian belt and to the lithosphere thinning responsible for the subsequent continental rifting. In this work, we propose a petrogenetic model for acidic to basic hypabissal bodies from southern Calabria in order to define the nature of sources, discriminate magmatic processes and supply a contribution in the geodynamic reconstruction of the Late Palaeozoic in the Calabria-Peloritani Orogen. In relation to their geochemical affinity, studied dykes have been divided in two groups: a medium- to high-K calc-alkaline and a tholeiitic one. Dykes belonging to the former group, andesitic and dacitic-rhyodacitic in composition, show typical features of subduction-related magmatism, such as LILE and LREE enrichments, depletions in HFSE, peaks in Rb, Th and Ce, accentuated troughs in Ba, Nb-Ta, P and Ti (White and Dupré, 1986; McCulloch and Gamble, 1991), contrasting with the late Hercynian collisional context. On the other side, features typical of intra-plate magmatic activity, such as a moderate enrichment in Ta, Nb, Ce, P, Zr, Hf and Sm relative to MORB composition are also present in studied rocks (Shimizu & Arculus, 1975; Pearce, 1982). REE-patterns are strongly to weakly fractionated for the andesitic rocks (Lan/Ybn = 10.03-13.98) and the dacitic-rhyodacitic ones (Lan/Ybn = 6.00 to 2.82), respectively. The latter rocks exhibit a very slight negative Eu anomaly, whereas no Eu anomaly is recognizable in the andesite

  16. Pb-Pb zircon ages of the Porto Nacional high-grade metamorphic terrain, northern portion of the Goias Massif, central Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Gorayeb, Paulo Sergio de Sousa; Moura, Candido Augusto Veloso [Para Univ., Belem, PA (Brazil). Centro de Geociencias]. E-mail: gorayebp@ufpa.br; c_moura@ufpa.br; Barros, Gisele Ribeiro de [Para Univ., Belem, PA (Brazil). Programa Institucional de Bolsas de Iniciacao Cientifica (PIBIC)]. E-mail: agbarros@amazon.com.br

    2000-03-01

    Single zircon Pb-evaporation ages were determined for a mafic granulite, two enderbites and a kinzigite of the Porto Nacional High-Grade Metamorphic Terrain (PNHGT) in the Goias massif. Zircons from mafic granulites and one of the enderbites of yielded average {sup 207} Pb/{sup 206} Pb ages of 2125{+-}3 Ma and 2153{+-}1 Ma, respectively, being interpreted as minimum ages of the igneous protoliths. The other enderbite, whose zircons presented round terminations, yielded an average {sup 207} Pb/{sup 206} Pb age of 2097 {+-} 2 Ma. Zircons from the kinzigite, displaying cores and rims overgrowth, presented {sup 207} Pb/{sup 206} Pb ages ranging between 2027 and 2115 Ma. However, a very homogeneous zircon crystal without overgrowth yielded age of 2100 {+-} 2 Ma, with a distinctive low Th/U value (0.02). This zircon is interpreted as a metamorphic crystal and its age probably sets the age of the granulite facies metamorphism, indicating that the PNHGT is a result of the Transamazonian thermotectonic event. (author)

  17. The cooling history and the depth of detachment faulting at the Atlantis Massif oceanic core complex

    Science.gov (United States)

    Schoolmeesters, Nicole; Cheadle, Michael J.; John, Barbara E.; Reiners, Peter W.; Gee, Jeffrey; Grimes, Craig B.

    2012-10-01

    Oceanic core complexes (OCCs) are domal exposures of oceanic crust and mantle interpreted to be denuded to the seafloor by large slip oceanic detachment faults. We combine previously reported U-Pb zircon crystallization ages with (U-Th)/He zircon thermochronometry and multicomponent magnetic remanence data to determine the cooling history of the footwall to the Atlantis Massif OCC (30°N, MAR) and help establish cooling rates, as well as depths of detachment faulting and gabbro emplacement. We present nine new (U-Th)/He zircon ages for samples from IODP Hole U1309D ranging from 40 to 1415 m below seafloor. These data paired with U-Pb zircon ages and magnetic remanence data constrain cooling rates of gabbroic rocks from the upper 800 m of the central dome at Atlantis Massif as 2895 (+1276/-1162) °C Myr-1 (from ˜780°C to ˜250°C); the lower 600 m of the borehole cooled more slowly at mean rates of ˜500 (+125/-102) °C Myr-1(from ˜780°C to present-day temperatures). Rocks from the uppermost part of the hole also reveal a brief period of slow cooling at rates of ˜300°C Myr-1, possibly due to hydrothermal circulation to ˜4 km depth through the detachment fault zone. Assuming a fault slip rate of 20 mm/yr (from U-Pb zircon ages of surface samples) and a rolling hinge model for the sub-surface fault geometry, we predict that the 780°C isotherm lies at ˜7 km below the axial valley floor, likely corresponding both to the depth at which the semi-brittle detachment fault roots and the probable upper limit of significant gabbro emplacement.

  18. Rapakivi texture in porphyritic dikes within the Karavanke Granitic Massif (Slovenia

    Directory of Open Access Journals (Sweden)

    Giuliano Bellieni

    2002-01-01

    Full Text Available The northern Karavanke Granitic Massif straddles the Slovenian–Austrian border. The investigated area lies in northern Slovenia, and extends from the western Slovenian–Austrian border to the east for about 30 km, with a maximum width of 2 km. The massif exhibits a bimodal magmatic association comprising mainly syenogranite and syenite with contemporaneous gabbroic rocks. Rocks of intermediate composition are less abundant and show field, textural and chemical features suggesting that they have formed as a result of the interaction (mixing and mingling between felsic and mafic magmas. Plagioclasemantled alkali feldspars occur in dikes of porphyritic syenite, which cut larger bodies of gabbroic rocks. Field, mineralogical, petrographic and geochemical evidences suggest that the porphyritic syenite is a hybrid rock, formed by the interaction of mafic and felsic magmas. The formation of plagioclase-mantled alkali feldspar can be explained by the introduction of alkali feldspar from felsic, syenogranitic magma into more mafic magma, causing local undercooling in the portion of mafic magma surrounding the crystals. This resulted in the growth of cellular plagioclase, with quartz infilling, in a thermally and compositionally equilibrating system.

  19. Constraining the deformation and exhumation history of the Ronda Massif, Southern Spain

    Science.gov (United States)

    Myall, Jack; Donaldson, Colin

    2016-04-01

    The Ronda peridotite, southern Spain is comprised of four peridotite units hosted within metasedimentary units of the Betic Cordillera, Western Alps. These four areas of differing mineral facies are termed: the Garnet Mylonite , the Foliated Spinel Peridotite, the Granular Spinel Peridotite and the Foliated Plagioclase Peridotite. Whilst two of these units show a strong NE-SW foliation, the granular unit has no foliation and the Plagioclase facies shows a NW-SE foliation. The massif is separated from the metasedimentary host through a mylonite shear zone to the NW and thrust faults to the SE. The Garnets contain rims of Kelyphite which when combined with the rims of Spinel on the Plagioclase crystals illustrate the complicated exhumation of this massif. The Kelyphite shows the breakdown of garnet back to spinel and pyroxene showing the deeper high pressure high temperature mineral is under shallowing conditions whereas in contrast to this the low pressure low temperature plagioclase crystals have spinel rims showing that they have been moved into deeper conditions. The P-T-t pathway of the massif suggests slow exhumation to allow for partial recrystallisation of not only the garnets and plagioclases but of a 100m band of peridotite between the Foliated Spinel Peridotite and the Granular Spinel Peridotite facies. The tectonic model for the Ronda Peridotite that best describes the field data and subsequent lab work of this study is Mantle Core complex and slab roll back models. These models support mantle uprising during an extensional event that whereby slab roll back of the subducting lithosphere provides uplift into a void and emplacement into the crust. Further extension and final exhumation causes rotation of a mantle wedge into its present day position.

  20. K-Ar ages of some metamorphic rocks of Oban massif and their implications for the tectonothermal evolution of Southeastern Nigeria

    International Nuclear Information System (INIS)

    Ekwueme, B.N.; Itaya, Tetsumaru; Yabe, Hisatomo

    2000-01-01

    The following K-Ar ages have been obtained on mineral separates from some metamorphic rocks in the Oban massif: amphibolites (592-930 Ma), banded gneisses (492-538 Ma), granodioritic gneiss (502 Ma), schists (514-519 Ma) and charnockite (481 Ma). Comparison of these ages with previous dates obtained by the Rb-Sr whole rock method and the Pb-Pb evaporation technique on single zircon throws light on the cooling history and orogenic events in the Oban massif. The banded gneiss in the Oban massif yields a zircon age of 1932±5 Ma, indicating that it was emplaced during the early Proterozoic (Eburnean orogeny). The K-Ar age of 492-538 Ma suggests that these rocks were metamorphosed during the Pan-African orogeny. This age is similar to the Rb-Sr isochron age of 510±10 Ma earlier suggested to be the age of migmatization in the Oban massif. The amphibolite yielded Rb-Sr isochron ages of 784±31 Ma and 1313±37 Ma. The age of 1313±37 Ma fits into the Kibaran event. The K-Ar hornblende age of 930±37 Ma on the same amphibolite strongly suggests that this amphibolite belongs to an event older than Pan-African (600±150 Ma) and has not been reset perfectly by the Pan-African event. The migmatitic schists in the Oban massif yielded a Rb-Sr isochron age of 527±16 Ma which has been interpreted as the age of its migmatization. One sample of this schist, however, gave a model age of 676±24 Ma. The K-Ar ages for the Oban massif schists (514-519 Ma) are close to the Rb-Sr isochron age of ca. 527 Ma and confirm that a metamorphic event occurred in the area at this time. This was followed by final cooling at 515±10 Ma. Charnockite in the Oban area has yielded a zircon age of 584±20 Ma, which is Pan-African. The age possibly dates the time of formation of the charnockites. The K-Ar age (481 Ma) obtained in this study is approximately 100 Ma younger than the zircon age and possibly dates the subsequent cooling of the charnockite through hornblende blocking temperature. (author)

  1. Cenozoic extensional tectonics of the Western Anatolia Extended Terrane, Turkey

    International Nuclear Information System (INIS)

    Cemen, I; Catlos, E J; Gogus, O; Diniz, E; Hancer, M

    2008-01-01

    The Western Anatolia Extended Terrane in Turkey is located on the eastern side of the Aegean Extended Terrane and contains one of the largest metamorphic core complexes in the world, the Menderes massif. It has experienced a series of continental collisions from the Late Cretaceous to the Eocene during the formation of the Izmir-Ankara-Erzincan suture zone. Based our field work and monazite ages, we suggest that the north-directed postcollisional Cenozoic extension in the region is the product of three consecutive stages, triggered by three different mechanisms. The first stage was initiated about 30 Ma ago, in the Oligocene by the Orogenic Collapse the thermally weakened continental crust along the north-dipping Southwest Anatolian shear zone. The shear zone was formed as an extensional simple-shear zone with listric geometry at depth and exhibits predominantly normal-slip along its southwestern end. But, it becomes a high-angle oblique-slip shear zone along its northeastern termination. Evidence for the presence of the shear zone includes (1) the dominant top to the north-northeast shear sense indicators throughout the Menderes massif, such as stretching lineations trending N10E to N30E; and (2) a series of Oligocene extensional basins located adjacent to the shear zone that contain only carbonate and ophiolitic rock fragments, but no high grade metamorphic rock fragments. During this stage, erosion and extensional unroofing brought high-grade metamorphic rocks of the Central Menderes massif to the surface by the early Miocene. The second stage of the extension was triggered by subduction roll-back and associated back-arc extension in the early Miocene and produced the north-dipping Alasehir and the south-dipping Bueyuek Menderes detachments of the central Menderes massif and the north-dipping Simav detachment of the northern Menderes massif. The detachments control the Miocene sedimentation in the Alasehir, Bueyuek Menderes, and Simav grabens, containing high

  2. STRUCTURAL FEATURES OF THE NİĞDE MASSIF IN THE ÇAMARDI (NİĞDE DISTRICT

    Directory of Open Access Journals (Sweden)

    Ramazan DEMİRCİOĞLU

    2017-04-01

    Full Text Available In the Çamardı (Niğde district, the Niğde Massif is composed of marbles, gneisses, quartzites and amphibolites. These rocks of the Massif have been cut by Cretaceous aged granodiorites. The Paleocene-Eocene aged low-grade metamorphic rocks constitute the autochthonous cover of the Massif. These units are tectonically overlain by the Upper Cretaceous-Paleocene aged flyschoid and island arc type rocks. The Oligocene-Quaternary aged terrestrial and volcanic rocks constitute the youngest units in the district. The metamorphics of the Niğde Massif have been subjected to at least four phase ductile deformation (D1, D2, D3, and D4 and folding. Through the D1 phase deformation, the rocks of the Massif have been folded as recumbent-isoclinal folds (F1-F2 phase folding and have gained a structure with a foliation (S1 which is parallel to the axial planes. Owing to the isoclinal and intense folding of the bedding planes (S0 of the rocks, bedding transposition have developed and transposed folding structures have formed. Through the D2 phase deformation, northeast-southwest trending and both northeast and southwest dipping map scale folds (F3 phase folding have developed. As a result of the interference of F1-F2 and F3 phase folds, in the district, folds, generated by Type-2 folding, have formed (mushroom folds. Second phase mesoscopic folds are of tight-isoclinal geometry and display asymmetrical and inclined fold feature. In the study area, as a result of   D3 phase folding a large dome structure has developed in the district. And D4 phase folds have formed map scale synformal and antiformal structures that are trending approximately perpendicular to D2 phase, plunging south-east and trending northwest-southeast. Through D4 phase deformation, the cover rocks have been deformed together with the basement rocks (F5 phase that they overlie. The microscopic observations show that Cretaceous-Eocene aged rocks have been subjected to low

  3. How are the emplacement of rare-element pegmatites, regional metamorphism and magmatism interrelated in the Moldanubian domain of the Variscan Bohemian Massif, Czech Republic?

    Czech Academy of Sciences Publication Activity Database

    Melleton, J.; Gloaguen, E.; Frei, D.; Novák, M.; Breiter, Karel

    2012-01-01

    Roč. 50, č. 6 (2012), s. 1751-1773 ISSN 0008-4476 Institutional support: RVO:67985831 Keywords : LCT pegmatite * rare-element-enriched magma * columbite-tantalite * LA-SF-ICP-MS dating * Variscan orogeny * Bohemian Massif * Moldanubian domain * Bohemian Massif (Czech Republic) Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.180, year: 2012

  4. Modeling the uplift in the Ardennes-Rhenish Massif: Mechanical weakening under the Eifel?

    NARCIS (Netherlands)

    Garcia-Castellanos, D.; Cloetingh, S.A.P.L.; van Balen, R.T.

    2000-01-01

    Middle Pleistocene uplift in the Eifel has been interpreted as the isostatic response of the lithosphere to a deep buoyant hot body. The spatial and temporal distribution of the uplift in the Ardennes-Rhenish Massif Region has recently been constrained by new data of river incision that have been

  5. Massification and Diversification as Complementary Strategies for Economic Growth in Developed and Developing Countries

    Science.gov (United States)

    Tyndorf, Darryl; Glass, Chris R.

    2016-01-01

    Numerous microeconomic studies demonstrate the significant individual returns to tertiary education; however, little empirical evidence exists regarding the effects of higher education massification and diversification agendas on long-term macroeconomic growth. The researchers used the Uzawa-Lucas endogenous growth model to tertiary education…

  6. Geophysical monitoring as an information source of rock massif behaviour

    Directory of Open Access Journals (Sweden)

    Pavel Bláha

    2008-06-01

    Full Text Available Geophysical measurements are an integral part of engineering-geological investigation where theypresent a wide range of useful information about the tested geological medium and about its geotechnicalqualities. Lately, repeated geophysical measurements in different time intervals have been used to judgethe changes occurring in the rock massif. These measurements bear the characteristics of total monitoring.This total monitoring contains series of repeated measurements and further an integrated spectrum of linkedactivities including evaluation, comparison with the warning state and making a decision about takingprecautions. From the range of geophysical methods and methodologies used for monitoring in full sensewe may mention, for example, continuous seismoacoustic measurements in mining constructions; (whichmay result even in recalling of the personnel, and further, also seismic measurements in the surroundingsof atomic power stations and measurements considering the protection against radioactive elements and their decay components.As a full monitoring we may also classify measurements in dumping sites with the aid of repeated geoelectrical measurements in the system of fixed electrodes under impermeable foils.These measurements are mostly carried out from time to time followed by taking immediate action when the foil is found damaged. In practice the term monitoring is used, although not very correctly, for all periodically repeated measurements, which do not result in taking action or interference, but supply a wide range of information about the rock massif behavior in time.

  7. K-Ar cooling age profile from Joinville massif (PR and SC, Brazil) and Dom Feliciano belt (SC, Brazil) - Tectonics entanglement

    International Nuclear Information System (INIS)

    Siga Junior, O.; Basei, M.A.S.; Kawashita, K.

    1990-01-01

    A K-Ar cooling age profile using different minerals from metamorphic rocks of the Joinville Massif and Dom Feliciano Belt is presented. Three main geochronological domains are distinguishable, from NW to SE: 1) Northern part of the Joinville Massif (NJM); 2) Southern part of the Joinville Massif (SJM) and 3) Dom Feliciano Belt (DBF). Geochronological domains 1 and 3 yielded K-Ar values in the range 800-500 Ma and 700-500 Ma, respectively, which show a clear influence of the Brasiliano Cycle. The granulite terrain comprising the SMJ exhibits ages older than 1700 Ma, indicating that this area was cool during the Late Proterozoic Brasiliano Cycle. The SJM and NJM limit is marked by a rapid Transition from Early Proterozoic ages in the SJM to Late Proterozoic ages in the NJM. On the other hand the contact between the SJM and DFB is interpreted as a thrust at a high, relatively cool crustal level. (author)

  8. Geophysical research results of buried relief and distribution groundwater runoff of the Aragats massif

    Directory of Open Access Journals (Sweden)

    V.P. Vardanyan

    2017-03-01

    Overall, the new data concerning the structure of the buried relief of Aragats massif and the distribution of its underground runoff allow to develop effective measures for the selection of underground waters and their rational usage for the purpose of water supply and irrigation.

  9. Some lessons in artificial regeneration from southwestern Oregon.

    Science.gov (United States)

    William I. Stein

    1955-01-01

    Natural reproduction has often proved undependable for restocking cutovers and burns in the mixed-conifer forest types of southwestern Oregon. These types, covering 6,000 square miles of productive forest land in the five southwestern Oregon counties, are composed of many species--principally Douglas fir, Pseudotsuga menziesii (Mirb.) Franco;...

  10. Temporal evolution of mineralization events in the Bohemian Massif inferred from the Re-Os geochronology of molybdenite

    Science.gov (United States)

    Ackerman, Lukáš; Haluzová, Eva; Creaser, Robert A.; Pašava, Jan; Veselovský, František; Breiter, Karel; Erban, Vojtěch; Drábek, Milan

    2017-06-01

    Molybdenite is a common mineral accompanying Sn-W, Au, and base metal mineralizations located in different geotectonic units of the Bohemian Massif, but it is also widespread in granitoids and/or related quartz veins/pegmatites forming disseminated Mo mineralization. Thirty Re-Os ages were obtained for molybdenite samples from the Bohemian Massif to provide constraints on the timing and duration of mineralization event(s) within the framework of previously published geochronological data for the host and/or associated rocks. The obtained data for Sn-W-(Li) deposits in the Erzgebirge metallogenetic province indicate the predominance of one and/or multiple short-time mineralization events taking place between ˜319 and 323 Ma, with the exception of the Krupka deposit associated with the Altenberg-Teplice caldera where the data may suggest prolonged activity until ˜315 Ma. The ages of the Pb-Zn-(Au-Mo) Hůrky u Rakovníka and Fe-Cu-As Obří důl mineralizations from the exocontacts of the Čistá pluton and Krkonoše-Jizera Plutonic Complex, respectively, provide evidence for synchronous emplacement of the ore and the associated granitic rocks. In contrast, the Padrť Fe-As-Mo mineralization postdates the age of the associated Padrť granite. Disseminated Mo mineralization in Cadomian and Variscan granitoids and/or related to quartz veins/pegmatites provides Re-Os ages that overlap with the previously published geochronological data for the host rocks, suggesting coeval evolution. Molybdenite samples from the Sázava suite granites of the Central Bohemian Plutonic Complex (CBPC) have resolvable younger ages than their host granites, but similar to the age of spatially related Au mineralization which is associated with the latest evolution of the CBPC.

  11. Upper Cretaceous to Pleistocene melilitic volcanic rocks of the Bohemian Massif: Petrology and mineral chemistry

    Czech Academy of Sciences Publication Activity Database

    Skála, Roman; Ulrych, Jaromír; Krmíček, Lukáš; Fediuk, F.; Balogh, K.; Hegner, E.

    2015-01-01

    Roč. 66, č. 3 (2015), s. 197-216 ISSN 1335-0552 Institutional support: RVO:67985831 Keywords : Bohemian Massif * Cenozoic volcanism * isotope geochemistry * melilitic rock * mineralogy * petrology Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.523, year: 2015

  12. Carboniferous high-pressure metamorphism of Ordovician protoliths in the Argentera Massif (Italy), Southern European Variscan belt

    Science.gov (United States)

    Rubatto, Daniela; Ferrando, Simona; Compagnoni, Roberto; Lombardo, Bruno

    2010-04-01

    The age of high-pressure metamorphism is crucial to identify a suitable tectonic model for the vast Variscan orogeny. Banded H P granulites from the Gesso-Stura Terrain in the Argentera Massif, Italy, have been recently described (Ferrando et al., 2008) relicts of high-pressure metamorphism in the western part of the Variscan orogen. Bulk rock chemistry of representative lithologies reveals intermediate silica contents and calc-alkaline affinity of the various cumulate layers. Enrichment in incompatible elements denotes a significant crustal component in line with intrusion during Ordovician rifting. Magmatic zircon cores from a Pl-rich layer yield scattered ages indicating a minimum protolith age of 486 ± 7 Ma. Carboniferous zircons (340.7 ± 4.2 and 336.3 ± 4.1 Ma) are found in a Pl-rich and a Pl-poor layer, respectively. Their zoning, chemical composition (low Th/U, flat HREE pattern and Ti-in-zircon temperature) and deformation indicate that they formed during the high-pressure event before decompression and mylonitisation. The proposed age for high-pressure metamorphism in the Argentera Massif proves that subduction preceded anatexis by less than 20 Ma. The new data allow a first-order comparison with the Bohemian Massif, which is located at the eastern termination of the Variscan orogen. Similarities in evolution at either end of the orogen support a Himalayan-type tectonic model for the entire European Variscides.

  13. Late Paleozoic volcanic rocks of the Intra-Sudetic Basin, Bohemian Massif: Petrological and geochemical characteristics

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Fediuk, F.; Lang, Miloš; Martinec, Petr

    2004-01-01

    Roč. 64, č. 2 (2004), s. 127-153 ISSN 0009-2819 R&D Projects: GA AV ČR(CZ) IAA3013903 Keywords : Late Paleozoic * volcanic rocks * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.643, year: 2004

  14. The Tonalá fault in southeastern Mexico: Evidence that the Central America forearc sliver is not being detached?

    Science.gov (United States)

    Guzman-Speziale, M.; Molina-Garza, R. S.

    2012-12-01

    The Tonalá fault is a NW-SE oriented feature that flanks the Chiapas Massif on its southwestern side. Several authors coincide that the fault originally developed as a right-lateral structure in the Jurassic, but was reactivated as a left-lateral fault in the Miocene. Seismicity along the fault is low: Only one earthquake with magnitude 5.0 or larger is reported along the Tonalá fault in the years 1964 to present. Fault-plane solutions determined by the Mexican Seismological Survey for earthquakes along the fault show left-lateral, strike-slip faulting. The Tonalá fault lies on the northwestern continuation of the Central America volcanic arc. The volcanic arc is the site of medium-sized (magnitudes up to 6.5) shallow, right-lateral, strike-slip earthquakes. This has led several workers to propose that the forearc sliver is being detached from the Caribbean plate along the arc, moving northward. GPS studies have confirmed relative motion between the Chortis block and the forearc sliver. Recent and current motion along the Tonalá fault is in contradiction with motion and detachment of the forearc sliver along the Central America volcanic arc. Left-lateral motion along it cannot accomodate northwest displacement of the forearc sliver. Motion of the Central America forearc would require NW directed compression between the continental shelf of Chiapas and the forearc itself, which is not observed. Therefore, either another fault (or faults) accomodates right-lateral motion and detachment of the forearc sliver, or the sliver is not being detached and relative motion between the forearc sliver and the Chortis block corresponds to displacement of the latter. We suggest that, as proposed by previous authors, the Tonalá fault is instead part of a fault system that runs from the state of Oaxaca (the Valle Nacional fault), forming an arc concave to the northeast, and running perpendicular to the maximum slope of subduction in the area.

  15. Casuses of deforestation in southwestern Madagascar

    DEFF Research Database (Denmark)

    Casse, Thorkil; Milhøj, Anders; Ranaivoson, Socrate

    2004-01-01

    Causes of deforestation are discussed in the case of southwestern Madagascar. Distinction is made between direct and indirect causes. The article ends up with an estimation of the value of agricultural land vs. an estimation of benefits from utilisation of non-timber forest products......Causes of deforestation are discussed in the case of southwestern Madagascar. Distinction is made between direct and indirect causes. The article ends up with an estimation of the value of agricultural land vs. an estimation of benefits from utilisation of non-timber forest products...

  16. 2014 annual site environmental report, Southwestern Power Administration

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-12-31

    Southwestern Power Administration’s Annual Site Environmental Report (ASER) serves as the chief reporting mechanism for site environmental performance information within the Department of Energy and as a valuable resource for shared and collaborative environmental protection and performance information to Agency stakeholders and members of the public living near Southwestern Power Administration’s (Southwestern) facilities and transmission line rights-of-ways. This ASER meets the requirements of Department of Energy (DOE) Order 231.B. Southwestern’s key environmental involvement includes an emphasis on the protection of ecological resources which is effectively accomplished through environmental program elements such as protecting water resources, generation of clean hydropower energy, oil spill prevention practices, elimination of green-house gas emissions, and comprehensive project reviews to ensure the protection of living organisms, migratory birds, Federally threatened or endangered species, and historic or cultural resources. Southwestern continues to actively minimize effects to natural resources and strive for continual improvement in the area of environmental compliance and sustainability while achieving the agency mission to market and deliver Federal hydroelectric power.

  17. The energy behind the power. Southwestern Power Administration 1994 annual report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    This is the Southwestern Power Administration 1994 annual report. The topics of the report include a letter to the secretary; an overview including the mission statement, a description of the Southwestern Federal Power System, financial statement, performance measurements, national performance review; year in review, summary of results, financial and statistical data and the Southwestern Power Administration Organization.

  18. Instrument-Aided Assessment of the Effect of Natural and Technogenic Factors on the Geomechanical State of a Massif Enclosing an HPP Turbine Room

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, N. N., E-mail: Abramov@goi.kolasc.net.ru; Epimakhov, Yu. A. [Russian Academy of Sciences, Mining Institute, Kola Scientific Center (Russian Federation)

    2016-05-15

    A package of geophysical criteria has been developed using seismic spatiotemporal tomography (SST) of a rock massif to perform an instrument-aided assessment of the effect of natural and technogenic factors on the geomechanical state of a rock massif enclosing an underground turbine room at an HPP. Results are presented for a detailed assessment for the underground turbine room at the Verkhnyaya Tuloma HPP on the Kola peninsula.

  19. Petrogenesis, detrital zircon SHRIMP U-Pb geochronology, and tectonic implications of the Upper Paleoproterozoic Seosan iron formation, western Gyeonggi Massif, Korea

    Science.gov (United States)

    Kim, Chang Seong; Jang, Yirang; Samuel, Vinod O.; Kwon, Sanghoon; Park, Jung-Woo; Yi, Keewook; Choi, Seon-Gyu

    2018-05-01

    This study involves investigations on the Upper Paleoproterozoic iron formation (viz., Seosan iron formation) from the Seosan Group, Gyeonggi Massif of the southwestern Korean Peninsula. It occurs as thin banded layers within meta-arkosic sandstone, formed by alternating processes of chemical (hydrothermal) and detrital depositions under a shallow marine environment. It mainly consists of alternating layers of iron oxides, mostly hematite, and quartz. Minor amounts of magnetite surrounded by muscovite, clinopyroxene and amphibole indicate hydrothermal alteration since its formation. Meta-arkosic sandstone is composed of recrystallized or porphyroclastic quartz and microcline, with small amounts of hematite and pyrite clusters. The Seosan iron formation has high contents of total Fe2O3 and SiO2 with positive Eu anomalies similar to those of other Precambrian banded iron formations, and its formation is clearly related to hydrothermal alteration since its deposition. Detrital zircon SHRIMP U-Pb geochronology data from a meta-arkosic sandstone (SN-1) and an iron formation (SN-2) show mainly two age groups of ca. 2.5 Ga and ca. 1.9-1.75 Ga. This together with intrusion age of the granite gneiss (ca. 1.70-1.65 Ga) clearly indicate that the iron formations were deposited during the Upper Paleoproterozoic. The dominant Paleoproterozoic detrital zircon bimodal age peaks preserved in the Seosan iron formation compare well with those from the South China Craton sedimentary basins, reflecting global tectonic events related to the Columbia supercontinent in East Asia.

  20. Large plates and small blocks: The Variscan orogeny in the Bohemian Massif

    Science.gov (United States)

    Kroner, Uwe; Romer, Rolf L.

    2017-04-01

    The Bohemian Massif of the Central European Variscides consists of several late Proterozoic / early Paleozoic low-strain crustal units, namely the Bruno-Vistulian continental block of the Laurussian plate that is juxtaposed with the Tepla-Barrandian Unit and the Lausitz block of the Gondwana plate. These pre-Variscan low-strain units are separated by high-strain zones that contain the mid- and lower crustal record of the Variscan orogeny (400-300 Ma), with nappes reflecting successive subduction exhumation events, voluminous migmatites and a wide range of geochemically contrasting granites. Although the principal constraints are undisputed, there is no consensus regarding the general tectonics of this area. Here we present a plate tectonic model explaining the Bohemian Massif as an orogenic wedge with a Gondwana pro-wedge and a Laurussia retro-wedge area. The principal formation steps are as follows. Subduction of the oceanic crust of the Gondwana plate, i.e. the southern part of the Rheic Ocean eventually followed by continental subduction of the distal Peri-Gondwana shelf produced the early Devonian (U)HP complexes now exposed in the uppermost allochthonous units. The arrival of the Tepla-Barrandian Cadomian block initiates a flip of subduction polarity, leading to the complete closure of the Rheic Ocean in the late Devonian coeval with the exhumation of the early Variscan (U)HP units. Caused by the Lausitz block entering the plate boundary zone in the early Carboniferous, this early subduction accretion stage was followed by continent continent collision. The resulting orogenic wedge is characterized by an intra-continental subduction zone in the pro-wedge area superimposed by the crustal stack of early and mid-Variscan accreted units. Due to heating of the subducted slab in the mantle, the isothermal exhumation of this deeply buried continental crust caused HT-LP metamorphism during the final transpressional stage. Lateral extrusion tectonics coeval with the

  1. Chromophoric Dissolved Organic Matter in Southwestern Greenland Lakes

    Science.gov (United States)

    Osburn, C. L.; Giles, M. E.; Underwood, G. J. C.

    2014-12-01

    Dissolved organic matter (DOM) is an important property of Arctic lake ecosystems, originating from allochthonous inputs from catchments and autochthonous production by plankton in the water column. Little is known about the quality of DOM in Arctic lakes that lack substantial inputs from catchments and such lakes are abundant in southwestern Greenland. Colored dissolved organic matter (CDOM), the fraction that absorbs ultraviolet (UV) and visible light, is the controlling factor for the optical properties of many surface waters and as well informs on the quality of DOM. We examined the quality of CDOM in 21 lakes in southwestern Greenland, from the ice sheet to the coast, as part of a larger study examining the role of DOM in regulating microbial communities in these lakes. DOM was size fractioned and absorbance and fluorescence was measured on each size fraction, as well as on bulk DOM. The specific ultraviolet absorbance (SUVA) at 254 nm (SUVA254), computed by normalizing absorption (a254) to dissolved organic carbon (DOC) concentration, provided an estimate of the aromatic carbon content of DOM. SUVA values were generally CDOM fluorescence was used to determine the relative abundance of allochthonous and autochthonous DOM in all size fractions. Younger lakes near the ice sheet and lakes near the coast had lower amounts of CDOM and appeared more microbial in quality. However, lakes centrally located between the ice sheet and the coast had the highest CDOM concentrations and exhibited strong humic fluorescence. Overall distinct differences in CDOM quality were observed between lake locations and among DOM size fractions.

  2. Uraninite, Coffinite and Brannerite from Shear-Zone Hosted Uranium Deposits of the Bohemian Massif (Central European Variscan Belt

    Directory of Open Access Journals (Sweden)

    Miloš René

    2017-03-01

    Full Text Available New mineralogical data are presented for shear-zone hosted uranium mineralisation from selected uranium deposits that occur in the Bohemian Massif. The uranium mineralisation is in high-grade metamorphic rocks of the Moldanubian Zone and/or in granitic rocks of the Moldanubian batholith and Bor pluton as complex uraninite–coffinite and uraninite–coffinite–brannerite assemblages. For analysed coffinites and brannerites, anomalous enrichment of Y (up to 3.4 wt % Y2O3 and Zr (up to 13.8 wt % ZrO2 is significant. The microprobe data indicate that coffinites from the Rožná and Okrouhlá Radouň uranium deposits contain variable PbO (0–4.3 wt %, FeO (0–2.5 wt %, Al2O3 (0–3.5 wt %, P2O5 (0–1.8 wt %, and CaO (0.7–3.5 wt %. Brannerite is present in unaltered and altered grains with variable concentrations of U4+ (0–0.5 apfu, U6+ (0.06–0.49 apfu, Ti (0.90–2.63 apfu, Ca (0.09–0.41 apfu, and low concentrations of Al (0–0.19 apfu, Th (0–0.04 apfu, Y (0–0.08 apfu, Zr (0–0.13 apfu and REE (0–0.14 apfu.

  3. Southwestern Avian Community Organization in Exotic Tamarix: Current Patterns and Future Needs

    Science.gov (United States)

    H. A. Walker

    2006-01-01

    Tamarisk (saltcedar: Tamarix), an invasive exotic tree native to the Eastern Hemisphere, is currently the dominant plant species in most southwestern riparian ecosystems at elevations below 1500 m. Tamarisk alters abiotic conditions and the floral composition of native southwestern riparian ecosystems and, in turn, affects native southwestern animal communities....

  4. Metagenomic identification of active methanogens and methanotrophs in serpentinite springs of the Voltri Massif, Italy

    Directory of Open Access Journals (Sweden)

    William J. Brazelton

    2017-01-01

    Full Text Available The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and bacteria in continental serpentinite springs has been limited. This report provides metagenomic and experimental evidence for active methanogenesis and methanotrophy by microbial communities in serpentinite springs of the Voltri Massif, Italy. Methanogens belonging to family Methanobacteriaceae and methanotrophic bacteria belonging to family Methylococcaceae were heavily enriched in three ultrabasic springs (pH 12. Metagenomic data also suggest the potential for hydrogen oxidation, hydrogen production, carbon fixation, fermentation, and organic acid metabolism in the ultrabasic springs. The predicted metabolic capabilities are consistent with an active subsurface ecosystem supported by energy and carbon liberated by geochemical reactions within the serpentinite rocks of the Voltri Massif.

  5. Mineral Deposit Data for Epigenetic Base- and Precious-metal and Uranium-thorium Deposits in South-central and Southwestern Montana and Southern and Central Idaho

    Science.gov (United States)

    Klein, T.L.

    2004-01-01

    Metal deposits spatially associated with the Cretaceous Boulder and Idaho batholiths of southwestern Montana and southern and central Idaho have been exploited since the early 1860s. Au was first discovered in placer deposits; exploitation of vein deposits in bedrock soon followed. In 1865, high-grade Ag vein deposits were discovered and remained economically important until the 1890s. Early high-grade deposits of Au, Ag and Pb were found in the weathered portions of the veins systems. As mining progressed to deeper levels, Ag and Pb grades diminished. Exploration for and development of these vein deposits in this area have continued until the present. A majority of these base- and precious-metal vein deposits are classified as polymetallic veins (PMV) and polymetallic carbonate-replacement (PMR) deposits in this compilation. Porphyry Cu and Mo, epithermal (Au, Ag, Hg and Sb), base- and precious-metal and W skarn, W vein, and U and Th vein deposits are also common in this area. The world-class Butte Cu porphyry and the Butte high-sulfidation Cu vein deposits are in this study area. PMV and PMR deposits are the most numerous in the region and constitute about 85% of the deposit records compiled. Several types of syngenetic/diagenetic sulfide mineral deposits in rocks of the Belt Supergroup or their equivalents are common in the region and they have been the source of a substantial metal production over the last century. These syngenetic deposits and their metamorphosed/structurally remobilized equivalents were not included in this database; therefore, deposits in the Idaho portion of the Coeur d'Alene district and the Idaho Cobalt belt, for example, have not been included because many of them are believed to be of this type.

  6. Paleomagnetism of Jurassic and Cretaceous rocks in central Patagonia: a key to constrain the timing of rotations during the breakup of southwestern Gondwana?

    Science.gov (United States)

    Geuna, Silvana E.; Somoza, Rubén; Vizán, Haroldo; Figari, Eduardo G.; Rinaldi, Carlos A.

    2000-08-01

    A paleomagnetic study in Jurassic and Cretaceous rocks from the Cañadón Asfalto basin, central Patagonia, indicates the occurrence of about 25-30° clockwise rotation in Upper Jurassic-lowermost Cretaceous rocks, whereas the overlying mid-Cretaceous rocks do not show evidence of rotation. This constrains the tectonic rotation to be related to a major regional unconformity in Patagonia, which in turn seems to be close in time with the early opening of the South Atlantic Ocean. The sense and probably the timing of this rotation are similar to those of other paleomagnetically detected rotations in different areas of southwestern Gondwana, suggesting a possible relationship between these and major tectonic processes related with fragmentation of the supercontinent. On the other hand, the mid-Cretaceous rocks in the region yield a paleopole located at Lat. 87° South, Long. 159° East, A95=3.8°. This pole position is consistent with coeval high-quality paleopoles of other plates when transferred to South American coordinates, implying it is an accurate determination of the Aptian (circa 116 Ma) geomagnetic field in South America.

  7. Effect of Aspect on Climate Variation in Mountain Ranges of Shen-nongjia Massif, Central China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi

    2018-01-01

    The aim of this study was to better understand the mechanisms of regional climate variation in mountain ranges with con-trasting aspects as mediated by changes in global climate. It may help predict trends of vegetation variations in native ecosystems in natural reserves. As measures of climate response, temperature and precipitation data from the north, east, and south-facing mountain ranges of Shennongjia Massif in the coldest and hottest months (January and July), different seasons (spring, summer, autumn, and win-ter) and each year were analyzed from a long-term dataset (1960 to 2003) to tested variations characteristics, temporal and spatial quan-titative relationships of climates. The results showed that the average seasonal temperatures and precipitation in the north, east, and south aspects of the mountain ranges changed at different rates. The average seasonal temperatures change rate ranges in the north, east, and south-facing mountain ranges were from –0.0210℃ /yr to 0.0143℃ /yr,–0.0166℃ /yr to 0.0311℃ /yr, and –0.0290℃ /yr to 0.0084℃ /yr, respectively,and seasonal precipitation variation magnitude were from –1.4940 mm/yr to 0.6217 mm/yr, –1.6833 mm/yr to 2.6182 mm/yr, and –0.8567 mm/yr to 1.4077 mm/yr, respectively. The climates variation trend among the three mountain ranges were different in magnitude and direction, showing a complicated change of the climates in mountain ranges and some inconsistency with general trends in global climate change. The climate variations were significantly different and positively correlated cross mountain ranges, revealing that aspects significantly affected on climate variations and these variations resulted from a larger air circulation sys-tem, which were sensitive to global climate change. We conclude that location and terrain of aspect are the main factors affecting dif-ferences in climate variation among the mountain ranges with contrasting aspects.

  8. Southwestern Power Administration Annual Report 2007

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-01-01

    “Renewable energy” isn’t just a catchphrase at Southwestern Power Administration (Southwestern). It describes the hydroelectric energy we market, and the energy that Southwestern’s employees bring to work every day, constantly challenging themselves to become more eff ective and effi cient in providing aff ordable, environmentally clean power to the American people. As Southwestern’s new Administrator, I have had the opportunity to view our operations from a fresh perspective, and I’m proud to share with you how a focus on continual improvement has been evident in accomplishments throughout the agency during fi scal year (FY) 2007. When the North American Electric Reliability Corporation (NERC) implemented new reliability standards, we met applicable implementation dates and exceeded NERC’s control performance standards throughout the year. When tasked with reducing the agency’s carbon footprint, we found ways to achieve an 8.7% reduction in energy intensity from last year without impacting our operational capabilities. And when faced with record-breaking infl ows into the reservoir projects from which we market power, we capitalized on the opportunity to provide customers with signifi cant quantities of supplemental energy. Our supplemental sales this year not only saved customers over $122 million, but increased Southwestern’s revenues -- a huge win-win for Southwestern’s ratepayers and the Nation’s taxpayers alike. Southwestern is proud of its role in protecting National and economic security by contributing to the diverse supply of domestically produced energy, operating and maintaining a safe and reliable transmission system, and ensuring good stewardship of our Nation’s water resources and environment. In FY 2007, Southwestern continued to repay all power costs to the American taxpayers by marketing and delivering approximately 5.6 billion kilowatthours of hydropower at cost-based rates to customers in our six-state region. This energy

  9. Canthyporus reebae sp. nov. from the Itremo and Andringitra mountains of central eastern Madagascar (Coleoptera: Dytiscidae: Hydroporinae).

    Science.gov (United States)

    Manuel, Michaël; Ramahandrison, Andriamirado T

    2017-06-01

    Canthyporus reebae sp. nov. is described from the south-eastern part of the Itremo mountain range and from the Andringitra massif in central eastern Madagascar. The new species is the second one of the genus Canthyporus Zimmermann, 1919 to be recorded from Madagascar, the other being C. pauliani Guignot, 1951, so far endemic to the northern massif of Tsaratanana. The habitus and male and female reproductive structures of the new species are illustrated. Canthyporus reebae sp. nov. differs from C. pauliani notably by larger size, less parallel-sided and more evenly convex habitus, paler pronotum, more weakly impressed body surface reticulation, and a different shape of the median lobe of aedeagus. Differences with similar C. hottentottus-group species from mainland Africa are also discussed. Data on habitat preferences of C. reebae sp. nov. and a distribution map of Malagasy Canthyporus are presented and discussed.

  10. Automated data collection based on RoboDiff at the ESRF beamline MASSIF-1

    Energy Technology Data Exchange (ETDEWEB)

    Nurizzo, Didier, E-mail: Didier.nurizzo@esrf.fr; Guichard, Nicolas; McSweeney, Sean; Theveneau, Pascal; Guijarro, Matias; Svensson, Olof; Mueller-Dieckmann, Christoph; Leonard, Gordon [ESRF, The European Synchrotron, 71, Avenue des Martyrs,CS 40220, 38043 Grenoble (France); Bowler, Matthew W. [EMBL Grenoble Outstation, 71 Avenue des Martyrs, CS90181, 38042 Grenoble Cedex 9 (France)

    2016-07-27

    The European Synchrotron Radiation Facility has a long standing history in the automation of experiments in Macromolecular Crystallography. MASSIF-1 (Massively Automated Sample Screening and evaluation Integrated Facility), a beamline constructed as part of the ESRF Upgrade Phase I program, has been open to the external user community since July 2014 and offers a unique completely automated data collection service to both academic and industrial structural biologists.

  11. The Vascular Flora of Rarău Massif (Eastern Carpathians, Romania. Note I

    Directory of Open Access Journals (Sweden)

    Adrian Oprea

    2012-10-01

    Full Text Available The present study is concerned with the flora of the Rarău Massif, an area lying in the northeastern part of Romania, nearby the town of Câmpulung Moldovenesc. This study attempt to list all the vascular plants (i.e. ferns, conifers, and flowering plants from the whole area of Rarău Massif. Till now, there are published several papers on this area, but no paper deals with the whole surface of Rarău Massif. The research was carried out between 2000 to 2011. During the study period, 1377 taxa (1089 species and 288 subspecies, belonging to 95 families and 411 genera; 43 of the species belong to Pteridophytes, 8 belongs to Gymnosperms, and 1038 belongs to Angiosperms (835 Dicotyledons, 203 Monocotyledons subdivisions. The largest families (in terms of the number of species and subspecies included are: Asteraceae (167, Poaceae (78, Brassicaceae (53, Rosaceae and Lamiaceae (50, Scrophulariaceae and Cyperaceae (47, Caryophyllaceae and Ranunculaceae (42. The highest number of species, of a certain genus, is like the next: Carex L. (39, Centaurea L. (25, Hieracium L. (21, Festuca L. (19, Senecio L. (12, Cirsium, Pilosella, and Poa (11, etc. Since the flora of the area is analysed according to Raunkiaer’s life forms, the results are as follows: Hemicryptophytes 605 species (H=55.6%, Cryptophytes (also called Geophytes 137 species (G=12.6%, Therophytes 120 species (11.0%, Phanerophytes 84 species (Ph=7.7%, Chamaephytes 57 species (Ch=5.2%, Hemitherophytes 77 species (Ht=7.1%, Helo-hydatophytes 8 species (HH=0.7%, and Epiphytes 1 species (Ep=0.1%. The phytogeographic elements are the next ones: European=375 species (36.6%, Eurasian=349 species (34.0%, Circumboreal=148 species (14.8%, Cosmopolite=37 species (3.6%, Carpathians=31 species (3.0%, Pontics=19 species (1.9%, Mediterranean-submediterrannean=11 species (1.1%, and Adventitious=2 species (0.2%. The number of endemic and near-endemic taxa (species and subspecies within the study area is 53 (5.2%.

  12. On the edge of Bantu expansions: mtDNA, Y chromosome and lactase persistence genetic variation in southwestern Angola

    Directory of Open Access Journals (Sweden)

    Beleza Sandra

    2009-04-01

    Full Text Available Abstract Background Current information about the expansion of Bantu-speaking peoples is hampered by the scarcity of genetic data from well identified populations from southern Africa. Here, we fill an important gap in the analysis of the western edge of the Bantu migrations by studying for the first time the patterns of Y-chromosome, mtDNA and lactase persistence genetic variation in four representative groups living around the Namib Desert in southwestern Angola (Ovimbundu, Ganguela, Nyaneka-Nkumbi and Kuvale. We assessed the differentiation between these populations and their levels of admixture with Khoe-San groups, and examined their relationship with other sub-Saharan populations. We further combined our dataset with previously published data on Y-chromosome and mtDNA variation to explore a general isolation with migration model and infer the demographic parameters underlying current genetic diversity in Bantu populations. Results Correspondence analysis, lineage sharing patterns and admixture estimates indicate that the gene pool from southwestern Angola is predominantly derived from West-Central Africa. The pastoralist Herero-speaking Kuvale people were additionally characterized by relatively high frequencies of Y-chromosome (12% and mtDNA (22% Khoe-San lineages, as well as by the presence of the -14010C lactase persistence mutation (6%, which likely originated in non-Bantu pastoralists from East Africa. Inferred demographic parameters show that both male and female populations underwent significant size growth after the split between the western and eastern branches of Bantu expansions occurring 4000 years ago. However, males had lower population sizes and migration rates than females throughout the Bantu dispersals. Conclusion Genetic variation in southwestern Angola essentially results from the encounter of an offshoot of West-Central Africa with autochthonous Khoisan-speaking peoples from the south. Interactions between the Bantus

  13. Hydration of the Atlantis Massif: Halogen, Noble Gas and In-Situ δ18O Constraints

    Science.gov (United States)

    Williams, M. J.; Kendrick, M. A.; Rubatto, D.

    2017-12-01

    A combination of halogen (Cl, Br, I), noble gases (He, Ne, Ar, Kr and Xe) and in situ oxygen isotope analysis have been utilized to investigate the fluid-mobile element record of hydration and alteration processes at the Atlantis Massif (30°N on the Mid-Atlantic Ridge). The sample suite investigated includes serpentinite, talc-amphibole ± chlorite schist and hydrated gabbro recovered by seafloor drilling undertaken at sites on a transect across the Atlantis Massif during IODP Expedition 357. Serpentine mesh and veins analysed in-situ by SHRIMP SI exhibit δ18O from 6‰ down to ≈0‰, suggesting serpentinization temperatures of 150 to >280°C and water/rock ratios >5. Differences of 1.5-2.5‰ are observed between adjacent generations of serpentine, but the δ18O range is similar at each investigated drilling site. Halogen and noble gas abundances in serpentinites, talc-amphibole schist and hydrated gabbro have been measured by noble gas mass spectrometry of both irradiated and non-irradiated samples. Serpentinites contain low abundances of halogens and noble gases (e.g. 70-430 ppm Cl, 4.7-12.2 x 10-14 mol/g 36Ar) relative to other seafloor serpentinites. The samples have systematically different Br/Cl and I/Cl ratios related to their mineralogy. Serpentinites retain mantle-like Br/Cl with a wide variation in I/Cl that stretches toward seawater values. Talc-amphibole schists exhibit depletion of Br and I relative to Cl with increasing Cl abundances, suggesting tremolite exerts strong control on halogen abundance ratios. Serpentinites show no evidence of interaction with halogen-rich sedimentary pore fluids. Iodine abundances are variable across serpentinites, and are decoupled from Br and Cl; iodine enrichment (up to 530 ppb) is observed within relatively oxidised and clay-bearing samples. Serpentinized harzburgites exhibit distinct depletion of Kr and Xe relative to atmospheric 36Ar in seawater. Oxygen isotope compositions and low abundances of both halogens

  14. Using remote sensing imagery and GIS to identify land cover and land use within Ceahlau Massif (Romania

    Directory of Open Access Journals (Sweden)

    GEORGE CRACU

    2014-11-01

    Full Text Available Using remote sensing imagery and GIS to identify land cover and land use within Ceahlău Massif (Romania. In this study we considerer land cover and land use asessment within Ceahlău Massif (Romania using satellite imagery and GIS . To achieve this goal, we used a Landsat 7 ETM + satellite image, which was processed using specialized software in analyzing satellite images and GIS software in several stages:  Downloading, importing and layer stack of all spectral bands composing satellite image;  Establishment of areas of interest for each category of land cover and land use, which were digitized on - screen and for which spectral signatures characteristics were established;  Supervised image classification using Maximum Likelihood Method;  Importing the resulting m ap (raster in GIS environment and creating the final land cover/land use map for Ceahlău Massif. In the study area we identified nine land cover/land use classes: deciduous forests, mixed forests, coniferous forests, secondary grasslands, subalpine vegeta tion, alpine meadows, agricultural land, lakes and built area. By analizing the spatial distribution of these classes, it was found that forests are the best represented class, occupying an area of 188.4 km² (56.4% of total, followed by secondary grassl and, which occupies an area of 68.2 km² (20.4% of total, lakes (26.6 km² or 7.98% of total and agricultural land (16.1 km² or 4.86%

  15. Cenozoic alkaline volcanic rocks with carbonatite affinity in the Bohemian Massif: Their sources and magma generation

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Štěpánková-Svobodová, Jana

    2014-01-01

    Roč. 46, 1/2 (2014), s. 45-58 ISSN 0369-2086 R&D Projects: GA AV ČR(CZ) IAA300130902 Institutional support: RVO:67985831 Keywords : alkaline volcanic rocks * melilitic rocks * carbonatites * magma generation * metasomatism * Cenozoic * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy

  16. Southwestern Power Administration Annual Report 2004-2006

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-01-01

    Confidence Commitment Cooperation These are words that spring to mind regarding Southwestern Power Administration’s performance during fiscal years (FY) 2004-2006 By offering innovative, customer-oriented service, working to improve system reliability and efficiency, and partnering with customers and other Federal power stakeholders, Southwestern has certainly exhibited all three of these qualities during these challenging yet productive years In fact, our cooperative working relationships were critical to our success during the severe and widespread drought conditions which prevailed throughout Southwestern’s marketing area for much of 2005-2006 When we proposed a temporary energy deferral program, our customers came on board by voluntarily taking less Federal hydropower than they were entitled to, enabling us to preserve system storage and fulfill our contract obligations during the crucial summer months of 2006 The U S Army Corps of Engineers (Corps) also helped improve our drought situation by allowing Southwestern more operational flexibility on a regional level Despite the challenges this critical drought period presented, Southwestern remained committed to fulfilling our mission and strategic goals From FY 2004 through FY 2006, we marketed and delivered all available Federal hydropower while meeting and even exceeding the reliability standards of the North American Electric Reliability Corporation (NERC) Our Power Operations Training Center in Springfield, Missouri, was cited as an “Example of Excellence” during a NERC readiness audit in October 2006; and as we have every year since NERC began measuring, Southwestern far exceeded the accepted NERC compliance ratings for power system operations reliability Our commitment to excellence and accountability has kept our repayment goals on target as well Revenues were sufficient to repay all annual expenses and the required principal investment in the Federal hydropower facilities Furthermore, the original

  17. Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif; Estudio geoquimico de los procesos de interaccion agua-roca sobre sistemas goetermales de aguas alcalinas en granitoides

    Energy Technology Data Exchange (ETDEWEB)

    Buil gutierrez, B; Garcia Sanz, S; Lago San Jose, M; Arranz Uague, E; Auque Sanz, L [Universidad de Zaragoza (Spain)

    2002-07-01

    The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

  18. Southwestern Power Administration Annual Report 2008

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-12-01

    Dear Secretary Chu, I am pleased to present the financial statements and operating data for Southwestern Power Administration (Southwestern) for Fiscal Year (FY) 2008. In FY 2008, Southwestern delivered over 7.3 billion kilowatt-hours of energy to its wholesale customers – nearly 31% more than average due to numerous record rainfall amounts in the southwest region. These record amounts produced revenues which exceeded the average annual revenue requirement by nearly $20 million and resulted in over $200 million in economic benefits to the region. Yet even as Southwestern exceeded its goals of marketing and delivering Federal hydroelectric power to our customers, we stayed focused on safety, security, and reliability. For example, we maintained our nearly 1,400 miles of high-voltage transmission lines, substations, and communications sites while achieving a Recordable Accident Frequency Rate of 0.0, a record that reflects Southwestern’s safety achievement of no recordable injuries for every 200,000 hours worked. We kept our rights-of-way secure from vegetation and other obstacles, work that not only supports our mission but also promotes reliability of the regional and National grid. We exceeded all North American Electric Reliability Corporation (NERC) Control Performance Standards (CPS- 1 and CPS-2), and maintained regulation and reserve obligations and reactive reserve margins to ensure the reliability of the bulk electric system, even during extended periods of restricted hydro operations due to unusually high project inflows. Finally, we continued our partnerships with the Department of Energy, the U.S. Army Corps of Engineers, our customers, and other Federal power stakeholders, partnerships that are vital to our continued success in marketing and delivering carbon-free, renewable, and domestically produced energy to our customers and to the Nation. Sincerely, Jon Worthington Administrator

  19. Late Cenozoic cooling history of the central Menderes Massif: Timing of the Büyük Menderes detachment and the relative contribution of normal faulting and erosion to rock exhumation

    Science.gov (United States)

    Wölfler, Andreas; Glotzbach, Christoph; Heineke, Caroline; Nilius, Nils-Peter; Hetzel, Ralf; Hampel, Andrea; Akal, Cüneyt; Dunkl, István; Christl, Marcus

    2017-10-01

    Based on new thermochronological data and 10Be-derived erosion rates from the southern part of the central Menderes Massif (Aydın block) in western Turkey, we provide new insights into the tectonic evolution and landscape development of an area that undergoes active continental extension. Fission-track and (U-Th)/He data reveal that the footwall of the Büyük Menderes detachment experienced two episodes of enhanced cooling and exhumation. Assuming an elevated geothermal gradient of 50 °C/km, the first phase occurred with an average rate of 0.90 km/Myr in the middle Miocene and the second one in the latest Miocene and Pliocene with a rate of 0.43 km/Myr. The exhumation rates between these two phases were lower and range from 0.14 to 0.24 km/Myr, depending on the distance to the detachment. Cosmogenic nuclide-based erosion rates for catchments in the Aydın block range from 0.1 to 0.4 km/Myr. The similarity of the erosion rates on both sides of the Aydın block (northern and southern flank) indicate that a rather symmetric erosion pattern has prevailed during the Holocene. If these millennial erosion rates are representative on a million-year timescale they indicate that, apart from normal faulting, erosion in the hanging wall of the Büyük Menderes detachment fault did also contribute to the exhumation of the metamorphic rocks.

  20. The ophiolite massif of Kahnuj (western Makran, Southern Iran): new geological and geochronological data; Le massif ophiolitique de Kahnuj (Makran occidental, Iran meridional): nouvelles donnees geologiques et geochronologiques

    Energy Technology Data Exchange (ETDEWEB)

    Kananian, A. [University of Tarbiat Modarress, Geological Dept., Faculty of Science, Teheran (Iran, Islamic Republic of); Juteau, Th.; Bellon, H. [Universite de Bretagne Occidentale, IUEM, 29 - Brest (France); Darvishzadeh, A. [University of Teheran, Geological Dept., Faculty of Science, Teheran (Iran, Islamic Republic of); Sabzehi, M. [Geological Survey of Iran, Teheran (Iran, Islamic Republic of); Whitechurch, H. [Universite Louis Pasteur, EOST, Institut de Physique du Globe, 67 - Strasbourg (France); Ricou, L.E. [Institut de Physique du Globe, 75 - Paris (France)

    2001-05-01

    The ophiolite massif of Kahnuj (600 km{sup 2}) consists, from bottom to top, of layered gabbros, isotropic gabbros and ouralite gabbros, agmatites of dioritic to plagio-granitic composition, a sheeted dyke complex and lastly a basaltic pillow lava unit. Amphiboles from gabbros were dated ({sup 40}K-{sup 40}Ar ages) between 156 and 139 Ma and the agmatites are nearly contemporaneous. Potassic granitic veins dated at 93-88 Ma are related to the development of the Ganj arc complex. (authors)

  1. Chromitites of the Akkarginskiy massif (the Southern Urals

    Directory of Open Access Journals (Sweden)

    D. E. Saveliev

    2018-03-01

    Full Text Available We consider the geological features of ultramafic rock and chrome ore deposits. It is shown that all studied deposits are podiform in morphology that is typical for the ophiolite ultramafic rocks. Morphological and chemical features of the accessory and oreforming spinels are described. Accessory chrome spinels from ultramafic rocks are middle-Cr and high-Cr in chemistry (>42% Cr2O3. All studied ore-forming chrome spinels from deposits in the Main Ore Zone are high-Cr (54–63% Cr2O3. Some middle-Cr oreforming spinels were found in deposit of the East Ore Zone (48% Cr2O3. We adduce a proof of the tectonic origin of present-day structure of the Akkarginskiy massif and its chrome ore deposits.

  2. Geochronology and geochemistry of Mesozoic intrusive rocks in the Xing'an Massif of NE China: Implications for the evolution and spatial extent of the Mongol-Okhotsk tectonic regime

    Science.gov (United States)

    Li, Yu; Xu, Wen-Liang; Tang, Jie; Pei, Fu-Ping; Wang, Feng; Sun, Chen-Yang

    2018-04-01

    This study presents new zircon U-Pb-Hf and whole-rock geochemical data for intrusive rocks in the Xing'an Massif of NE China, with the aim of furthering our understanding of the evolution and spatial influence of the Mongol-Okhotsk tectonic regime. Zircon U-Pb dating indicates that five stages of Mesozoic magmatism are recorded in the Xing'an Massif, namely during the Middle Triassic ( 237 Ma), the Late Triassic ( 225 Ma), the Early Jurassic ( 178 Ma), the Middle Jurassic ( 168 Ma), and the late Early Cretaceous ( 130 Ma). The Middle Triassic-Early Jurassic intrusive rocks in the Xing'an Massif are dominantly granodiorites, monzogranites, and syenogranites that formed from magma generated by partial melting of newly accreted continental crust. Geochemistry of the Middle Triassic-Early Jurassic granitoid suites of the Xing'an Massif indicates their formation at an active continental margin setting, related to the southwards subduction of the Mongol-Okhotsk oceanic plate. The Middle Jurassic monzogranites in the Xing'an Massif are geochemically similar to adakites and have εHf(t) values (+3.8 to +5.8) and Hf two-stage model ages (TDM2; 979-850 Ma) that are indicative of derivation from magma generated by partial melting of thickened juvenile lower crust. The Middle Jurassic monzogranites formed in a compressional setting related to the closure of the Mongol-Okhotsk Ocean. The late Early Cretaceous intrusive rocks in the Xing'an Massif are dominated by A-type granitoids that are associated with bimodal volcanic rocks, suggesting their formation in an extensional environment related to either (i) delamination of a previously thickened region of the crust, associated with the Mongol-Okhotsk tectonic regime; (ii) the subduction of the Paleo-Pacific Plate; or (iii) the combined influence of these two tectonic regimes.

  3. Uranium mineralization possibilities in metamorphic Massif of Isla de Juventud, Cuba

    International Nuclear Information System (INIS)

    Gongora Dominguez, L.E.; Llanes Castro, A.I.; Pena Fortes, B.; Capote Rodriguez, G.

    1996-01-01

    The geologic and metallogenic characteristic of the metamorphic Massif shows the presence of possible uranium vein type mineralization as a result of a hidrotermal genetic process. Metalliferous fluids rising along the fault system were responsible for the deposition of the uranium in the reduction zones, i.e. presence of pyrite, organic matter and others. This type of uranium minerization is proposed for the Bibijagua area and for the Revolucion and Lela area the same type is expected. The gamma spectrometric analysis was used to evaluate the geological samples

  4. Granitic magma emplacement and deformation during early-orogenic syn-convergent transtension: The Stare Sedlo complex, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Tomek, Filip; Žák, J.; Chadima, Martin

    2015-01-01

    Roč. 87, JUL (2015), s. 50-66 ISSN 0264-3707 Institutional support: RVO:67985831 Keywords : anisotropy of magnetic susceptibility (AMS) * Bohemian Massif * pluton emplacement * granite * transtension * Variscan orogeny Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.926, year: 2015

  5. Late Cenozoic thrusting of major faults along the central segment of Longmen Shan, eastern Tibet: Evidence from low-temperature thermochronology

    Science.gov (United States)

    Tan, Xi-Bin; Xu, Xi-Wei; Lee, Yuan-Hsi; Lu, Ren-Qi; Liu, Yiduo; Xu, Chong; Li, Kang; Yu, Gui-Hua; Kang, Wen-Jun

    2017-08-01

    The Cenozoic orogenic process of the Longmen Shan (LMS) and the kinematics of major faults along the LMS are crucial for understanding the growth history and mechanism of the eastern Tibetan Plateau. Three major faults, from west to east, are present in the central segment of the LMS: the Wenchuan-Maoxian Fault (WMF), the Beichuan-Yingxiu Fault (BYF), and the Jiangyou-Guanxian Fault (JGF). Previous researchers have placed great impetus on the Pengguan Massif, between the WMF and BYF. However, limited low-temperature thermochronology data coverage in other areas prevents us from fully delineating the tectonic history of the LMS. In this study, we collect 22 samples from vertical profiles in the Xuelongbao Massif and the range frontal area located at the hanging walls of the WMF and JGF respectively, and conduct apatite and zircon fission track analyses. New fission track data reveal that the Xuelongbao Massif has been undergoing rapid exhumation with an average rate of 0.7-0.9 mm/yr since 11 Ma, and the range frontal area began rapid exhumation at 7.5 Ma with total exhumation of 2.5-4.5 km. The exhumation histories indicate that the three major faults (WMF, BYF and JGF) in the central LMS are all reverse faults, and show a basinward in-sequence propagation from middle Miocene to present-day. Such a pattern further implies that upper crustal shortening is the primary driver for the LMS' uplift during the Late Cenozoic. Nevertheless, middle-lower crustal deformation is difficult to be constrained by the exhumation histories, and its contribution to LMS' uplift cannot be ruled out.

  6. Population dynamics of caribou herds in southwestern Alaska

    Directory of Open Access Journals (Sweden)

    Patrick Valkenburg

    2003-04-01

    Full Text Available The five naturally occurring and one transplanted caribou (Rangifer tarandus granti herd in southwestern Alaska composed about 20% of Alaska's caribou population in 2001. All five of the naturally occurring herds fluctuated considerably in size between the late 1800s and 2001 and for some herds the data provide an indication of long-term periodic (40-50 year fluctuations. At the present time, the Unimak (UCH and Southern Alaska Peninsula (SAP are recovering from population declines, the Northern Alaska Peninsula Herd (NAP appears to be nearing the end of a protracted decline, and the Mulchatna Herd (MCH appears to now be declining after 20 years of rapid growth. The remaining naturally occurring herd (Kilbuck has virtually disappeared. Nutrition had a significant effect on the size of 4-month-old and 10-month-old calves in the NAP and the Nushagak Peninsula Herd (NPCH and probably also on population growth in at least 4 (SAP, NAP, NPCH, and MCH of the six caribou herds in southwestern Alaska. Predation does not appear to be sufficient to keep caribou herds in southwestern Alaska from expanding, probably because rabies is endemic in red foxes (Vulpes vulpes and is periodically transferred to wolves (Canis lupus and other canids. However, we found evidence that pneumonia and hoof rot may result in significant mortality of caribou in southwestern Alaska, whereas there is no evidence that disease is important in the dynamics of Interior herds. Cooperative conservation programs, such as the Kilbuck Caribou Management Plan, can be successful in restraining traditional harvest and promoting growth in caribou herds. In southwestern Alaska we also found evidence that small caribou herds can be swamped and assimilated by large herds, and fidelity to traditional calving areas can be lost.

  7. Contribution of U-Pb geochronology to characterizing the Cadomian magmatism of the southeastern French Massif Central and of the related uranium-ore at Bertholene

    International Nuclear Information System (INIS)

    Leveque, Marie-Helene

    1990-01-01

    U-Pb geochronology and whole-rock geochemistry (major, trace and rare earth elements) were applied to various ortho- and paragneiss formations of the southeastern part of the French Massif Central. The Mendic granite and the Les Palanges granite were dated at 603 ± 9 Ma and 540 ± 18 Ma, respectively. Their micaschist host-rocks show a multi-episodic evolution that matches the U-Pb data obtained on metasediments and leucogranites of the Variscan Orogen. An old zircon source was detected at 1.87 Ga in the Les Palanges micaschist, while, seemingly, this heritage was wiped out of the Mendic micaschist during the Cadomian events. In the Decazeville gneiss, where a crustal component of unknown age has been detected, the major event is the Variscan migmatization. At Bertholene, the geochronology of uranium ores associated to the Les Palanges orthogneiss evidenced two periods of emplacement: -the relicts of the first phase, of Liassic age at 173 ± 9 Ma, are restricted to an uranium oxide; -the second phase, related to coffinites, represents the economical ore emplaced from Oligocene until Recent times, generated through remobilization of the Liassic stock. A comparison between the geochronological data from the ore, and of those from its granite host, suggests a genetic relationship between the Cadomian magmatism and the U-concentrations, spatially linked to the unconformity between the Les Palanges basement and its Permo-Carboniferous cover series. Metamictization of the source minerals combined with tectonic processes would be responsible for the release of uranium. Uranium-rich minerals from Bertholene, from Lodeve and from Les Pierres-Plantees have been subjected to trial dating by the isotopic Xe-Xe method, which confirms the evolution admitted for those occurrences. This technique is demonstrably expeditious and faithful. Various phenomena were investigated, at the scale of the crystalline structure, related to the xenon energy states and to the problem of rare

  8. Transformational Leadership and Teacher Motivation in Southwestern Arizona High Schools

    Science.gov (United States)

    Reynolds, Catherine L.

    2009-01-01

    The purpose of this study was to explore the relationship between transformational leadership and teacher motivation in Southwestern Arizona high schools. Teachers in a school district in Southwestern Arizona comprised of high schools were surveyed using two instruments, Leithwood and Jantzi's (1998) The Leadership and Management of Schools in…

  9. Distribution of uranium, thorium and potassium in the alkaline rocks of Pocos de Caldas massif

    International Nuclear Information System (INIS)

    Rocha, E.B.

    1985-01-01

    The Pocos de Caldas massif, with area about 800 Km 2 , represents the greatest complex of alkaline rocks existent in the American continent. Although values of U and Th are well Known in the mineralized areas, few has been registered with respect to the distribution of those elements outside the ore deposits. The rocks of the massif, in general, present high contents of U and Th when confronted with the surrouding country rocks. The distribution of the U and Th appoint a relevant additional data in the discussion on the hypothesis of nepheline syenites bodies formation in Pocos de Caldas by crystal fractionation processes. In this work are provided results of the U, Th and K distribution in the main petrographic facies occurring in the several studies places of the massif, yielded by gamma-ray spectrometric analysis of the samples. Those analysis disclose that khibinites present average values about 38 ppm U and 120 ppm Th; lujavrites, about 14 ppm U and more than 70 ppm Th; U-Th depleted nepheline synites, about 12 ppm U and 38 ppm Th, Th/U ratios are close to 3,0 in the nepheline syenites, about 3,7 in the phonolites, reaching values close to 4,0 in the khibinites. These values are comparable with others Th/U ratios of selected series of alkaline rocks reported in the international literature. Uranium and Th comparative data, attained by delayed neutron counting activation analysis also are given. The results obtained for the fluorimetric analysis show loss of U leaching is greater in the fine-grained rocks (phonolites) than coarse-grained ones (lujavrites, Khibinites). The autoradiographic studies reveal that radioactive elements are found concentrated in mineral phases. A new assessment of the radiogenic heat production it is also available. (Author) [pt

  10. Research on Structure Innovation of Agricultural Organization in China's Southwestern Mountainous Regions

    OpenAIRE

    Du, Qiang; Luo, Min; Wang, Ping

    2012-01-01

    Taking agricultural organization in China's southwestern mountainous regions as research object, on the basis of analysis of the status quo of agricultural organization development in China's southwestern mountainous regions, we use related theoretical knowledge on economics and organization science, we probe into the process of innovation and mechanism of action concerning the structure of agricultural organization in China's southwestern mountainous regions over the past 30 years. Finally w...

  11. U-Pb zircon geochronology and Sm-Nd-Pb isotopic constraint for precambrian plutonic rocks in the northeastern part of Ryeongnam massif, Korea

    International Nuclear Information System (INIS)

    Chang, Ho-Wan

    2003-01-01

    The Ryeongnam massif is composed of Precambrian gneisses, Paleozoic and Mesozoic sedimentary rocks and extensive Triassic-Jurassic plutonic rocks of felsic to mafic composition. In the northeast Ryeongnam massif, the oldest rocks belong to the Sobaegsan gneiss complex, which is composed of orthogneisses, paragneisses and mafic plutonic rocks. U-Pb zircon ages for the felsic and mafic intrusive bodies within the Sobaegsan gneiss complex are: the Icheon granite gneiss, 2357±43 and 2342±47 Ma; the Buncheon granite gneiss, 1963±5 Ma; the Pyeonghae granite gneiss, 1936±21 Ma; the Ogbang amphibolite, 1918±10 Ma; the Imwon leucogranite gneiss, 1826±20 Ma. The Hyeondong biotite schist, which is intruded by the Buncheon granite gneiss and the Ogbang amphibolite, yielded an age of 2271±44 Ma. The Nd-Sm-Pb isotopic data indicate that the felsic plutonic rocks are derived from an older Archean crust. The Nd T DM ages are Archean, and the εNd values are negative for the felsic rocks and positive for the amphibolite. Common Pb isotope compositions also indicate a crustal source for the felsic intrusives. The U-Pb ages of Precambrian rocks of the Ryeongnam massifs are similar to those in the Gyeonggi massif, and may have a similar crustal evolutionary history. The Precambrian rocks of South Korea could be related either to the North China block or to the South China block, as the isotope ages and patterns are not unique to either block. Similarly, a geologic correlation with Japan, although possible, is tenuous at present. (author)

  12. Environmental Assessment for power marketing policy for Southwestern Power Administration

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-01

    Southwestern Power Administration (Southwestern) needs to renew expiring power sales contracts with new term (10 year) sales contracts. The existing contracts have been in place for several years and many will expire over the next ten years. Southwestern completed an Environmental Assessment on the existing power allocation in June, 1979 (a copy of the EA is attached), and there are no proposed additions of any major new generation resources, service to discrete major new loads, or major changes in operating parameters, beyond those included in the existing power allocation. Impacts from a no action plan, proposed alternative, and market power for less than 10 years are described.

  13. Environmental Assessment for power marketing policy for Southwestern Power Administration

    International Nuclear Information System (INIS)

    1993-01-01

    Southwestern Power Administration (Southwestern) needs to renew expiring power sales contracts with new term (10 year) sales contracts. The existing contracts have been in place for several years and many will expire over the next ten years. Southwestern completed an Environmental Assessment on the existing power allocation in June, 1979 (a copy of the EA is attached), and there are no proposed additions of any major new generation resources, service to discrete major new loads, or major changes in operating parameters, beyond those included in the existing power allocation. Impacts from a no action plan, proposed alternative, and market power for less than 10 years are described

  14. Modelling the Middle Pleistocene uplift in the Ardennes-Rhenish Massif: Thermo-mechanical weakening under the Eifel?

    NARCIS (Netherlands)

    Garcia-Castellanos, D.; Cloetingh, S.A.P.L.; van Balen, R.T.

    2000-01-01

    Middle Pleistocene uplift in the Eifel has been interpreted as the isostatic response of the lithosphere to a deep buoyant hot body. The spatial and temporal distribution of the uplift in the Ardennes-Rhenish Massif Region has recently been constrained by new data of river incision that have been

  15. Coral assemblages are structured along a turbidity gradient on the Southwestern Gulf of Mexico, Veracruz

    Science.gov (United States)

    Jordán-Garza, A. G.; González-Gándara, C.; Salas-Pérez, J. J.; Morales-Barragan, A. M.

    2017-04-01

    Corals on the reef corridor of the southwestern Gulf of Mexico have evolved on a terrigenous shallow continental shelf under the influence of several natural river systems. As a result, water turbidity on these reefs can be high, with visibility as low as turbidity and chlorophyll-a, the coral species composition and environmental variables were analyzed for the three main reef systems of the reef corridor of the southwestern Gulf of Mexico. Completeness of the data set was assessed using species accumulation curves and non-parametric estimators of species richness. Differences in coral assemblages' composition between the reef systems were investigated using univariate (ANOVA) and multivariate (nMDS, ANOSIM, SIMPER) analyses and the relationship between the assemblages and environmental data was assessed using a forward selection process in canonical correspondence analysis (CCA) to eliminate non-significant environmental variables. The northern and central Veracruz reef systems share a similar number of coral species (p=0.78 mult. comp.) and both showed higher species richness than the southern system (pturbidity and productivity were significant on the final CCA configuration, which showed a gradient of increasing turbidity from north to south. Reef geomorphology and the effect of turbidity help explain differences in coral assemblages' composition. More studies are necessary to establish if turbidity could function as a refuge for future environmental stress. Each Veracruz reef system is at the same time unique and shares a pool of coral species. To protect these ecosystems it is necessary to effectively manage water quality and consider coral diversity on the reef corridor of the southwestern Gulf of Mexico.

  16. Petrographic, geochemical and isotopic evidence of crustal assimilation processes in the Ponte Nova alkaline mafic-ultramafic massif, SE Brazil

    Science.gov (United States)

    Azzone, Rogério Guitarrari; Montecinos Munoz, Patricio; Enrich, Gaston Eduardo Rojas; Alves, Adriana; Ruberti, Excelso; Gomes, Celsode Barros

    2016-09-01

    Crustal assimilation plus crystal fractionation processes of different basanite magma batches control the evolution of the Ponte Nova cretaceous alkaline mafic-ultramafic massif in SE Brazil. This massif is composed of several intrusions, the main ones with a cumulate character. Disequilibrium features in the early-crystallized phases (e.g., corrosion and sieve textures in cores of clinopyroxene crystals, spongy-cellular-textured plagioclase crystals, gulf corrosion texture in olivine crystals) and classical hybridization textures (e.g., blade biotite and acicular apatite crystals) provide strong evidence of open-system behavior. All samples are olivine- and nepheline-normative rocks with basic-ultrabasic and potassic characters and variable incompatible element enrichments. The wide ranges of whole-rock 87Sr/86Sri and 143Nd/144Ndi ratios (0.70432-0.70641 and 0.512216-0.512555, respectively) are indicative of crustal contribution from the Precambrian basement host rocks. Plagioclase and apatite 87Sr/86Sr ratios (0.70422-0.70927) obtained for the most primitive samples of each intrusion indicate disequilibrium conditions from early- to principal-crystallization stages. Isotope mixing-model curves between the least contaminated alkaline basic magma and heterogeneous local crustal components indicate that each intrusion of the massif is differentiated from the others by varied degrees of crustal contribution. The primary mechanisms of crustal contribution to the Ponte Nova massif involve the assimilation of host rock xenoliths during the development of the chamber environment and the assimilation of partial melts from the surrounding host rocks. Thermodynamic models using the melts algorithm indicate that parental alkaline basic magmas can be strongly affected by contamination processes subsequently to their initial stages of crystallization when there is sufficient energy to assimilate partial melts of crustal host rocks. The assimilation processes are considered to

  17. Significance of geological units of the Bohemian Massif, Czech Republic, as seen by ambient noise interferometry

    Czech Academy of Sciences Publication Activity Database

    Růžek, Bohuslav; Valentová, L.; Gallovič, F.

    2016-01-01

    Roč. 173, č. 5 (2016), s. 1663-1682 ISSN 0033-4553 R&D Projects: GA ČR GAP210/12/2336; GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : ambient noise * geological units * Bohemian Massif * velocity model Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.591, year: 2016

  18. Influence of the Istranca-Rhodope Massifs and strands of the North Anatolian Fault on oil potential of Thrace Basin, NW Turkey

    International Nuclear Information System (INIS)

    Coskun, B.

    2000-01-01

    The Thrace Basin (NW Turkey) is an intermontane trough bounded to the north and west by the granitic and metamorphic rocks of the Istranca and Rhodope Massifs. Recent subsurface studies of the NW portion of the Thrace Basin have led to the identification of two trends in geothermal gradient, both of which are oriented approximately NW-SE (i.e. parallel to the depositional axis of the basin). Geological and geophysical data indicate that, due to the thrust of the Istranca Massif upon the Rhodope Massif, the subsurface temperature may have increased in the northern part of the basin. Other controls were wrench-fault activity of the Splays of the North Anatolian Fault (SNAF) and continuing basinal subsidences. The thermal history of the southern part of the basin was affected by Miocene ophiolitic emplacement to the west in Greece. The presence of a belt of intrabasinal palaeotopography (mainly Palaeozoic rocks) also contributed to increased geothermal gradients in the southern part of the study area. The basin is divisible into northern and southern zones of subsidence, which are separated by the Kuleli-Babaeski High. During the Oligocene, subsidence rates were highest in the northern zone and in the western sector of the southern zone. Later, during the Miocene, basin subsidence was associated with intense tectonic activity of the SNAF and with the emplacement of ophiolites to the west. A map of the top of the oil generation zone, based on TTI values calculated by the Lopatin method, indicates the presence of two maturation zones in the basin ; these were separated by the Late Oligocene Kuleli-Babaeski High. Oil generation in these zones was influenced by rapid subsidence, by a NW-SE oriented wrench fault system associated with the NAF and also by tectonic activity of the Istranca and Rhodope Massifs in the study area

  19. Internal structure of the Aar Massif: What can we learn in terms of exploration for deep geothermal energy?

    Science.gov (United States)

    Herwegh, Marco; Baumberger, Roland; Wehrens, Philip; Schubert, Raphael; Berger, Alfons; Maeder, Urs; Spillmann, Thomas

    2014-05-01

    The successful use of deep geothermal energy requires 3D flow paths, which allow an efficient heat exchange between the surrounding host rocks and the circulating fluids. Recent attempts to exploit this energy resource clearly demonstrate that the new technology is facing sever problems. Some major problems are related to the prediction of permeability, the 3D structure of the flow paths and the mechanical responses during elevated fluid pressures at depths of several kilometers. Although seemingly new in a technical perspective, nature is facing and solving similar problems since the beginning of the Alpine orogeny. Based on detailed studies in the Hasli Valley (Aar Massif) we can demonstrate that deformation and fluid flow are strongly localized along mechanical anisotropies (e.g. lithological variations, brittle and ductile faults). Some of them already evolved during Variscan and post-Variscan times. Interestingly, these inherited structures are reactivated over and over again during the Alpine orogeny. Their reactivation occurred at depths of ~13-15 km with elevated temperatures (400-475°C) and involved both ductile and brittle deformation processes. Brittle deformation in form of hydrofracking was always present due to the circulating fluids. It is this process, which was and still is responsible for seismic activity. With progressive uplift and exhumation of the Aar Massif, ductile deformation structures became replaced by brittle cataclasites and fault gouges during fault activity at shallower crustal levels. Existing hydrotest data from the Grimsel Test Site (Nagra's underground research laboratory) indicate that these brittle successors of the ductile shear zones are domains of enhanced recent fluid percolation. Note that although being exposed today, the continuation of these fault structures are still active at depth in both brittle and ductile deformation modes, a fact that can be inferred from recent uplift rates and the active seismicity. On the

  20. Problems of geologic survey of high level radioactive waste repositories illustrated on the testing site in the Melechov Massif

    International Nuclear Information System (INIS)

    Mlcoch, B.

    1997-01-01

    Major attention is paid to problems associated with the geologic maps of the prospective repository site, which lies within the Bohemian Massif. Structural geology, survey through boreholes, and primary database are also discussed briefly. (P.A.)

  1. Permo-Carboniferous volcanism in late Variscan continental basins of the Bohemian Massif (Czech Republic): geochemical characteristic

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Pešek, J.; Štěpánková-Svobodová, Jana; Bosák, Pavel; Lloyd, F. E.; Seckendorff, von, V.; Lang, Miloš; Novák, Jiří Karel

    2006-01-01

    Roč. 66, č. 1 (2006), s. 37-56 ISSN 0009-2819 R&D Projects: GA AV ČR(CZ) IAA3013903 Institutional research plan: CEZ:AV0Z30130516 Keywords : Permo-Carboniferous * volcanics * continental basin * Bohemian Massif * underplating * crustal anatexis * Sr-Nd isotopes Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.824, year: 2006

  2. AQUIFER IN AJAOKUTA, SOUTHWESTERN NIGERIA

    African Journals Online (AJOL)

    2005-03-08

    Mar 8, 2005 ... To establish the feasibility of water supply in a basement complex area ofAjaokuta, Southwestern Nigeria, pumping test results were used to investigate the storage properties and groundwater potential of the aquifer. The aquifer system consists of weathered and weathered/fractured zone of decomposed ...

  3. Temporal evolution of mineralization events in the Bohemian Massif inferred from the Re-Os geochronology of molybdenite

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Haluzová, Eva; Creaser, R. A.; Pašava, J.; Veselovský, F.; Breiter, Karel; Erban, V.; Drábek, M.

    2017-01-01

    Roč. 52, č. 5 (2017), s. 651-662 ISSN 0026-4598 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : Re-Os * geochronology * molybdenite * Bohemian Massif * granite Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 3.396, year: 2016

  4. Miocene metamorphism of pan-African granites in the Edough Massif (NE Algeria)

    International Nuclear Information System (INIS)

    Hammor, D.; Lancelot, J.

    1998-01-01

    The Edough Massif is the eastern most crystalline core of the Maghrebides that represents the African segment of the west Mediterranean Alpine belt. U-Pb zircon dating provides upper intercept ages of 595± My and 606±55 My and orthogneiss of the lower unit and a deformed leucogranite of the upper pelitic unit, respectively. These ages suggest emplacement of the two granitoids during the Pan-African orogeny. Monazites from a paragneiss sample gave a 18± My U-Pb age that points to a Miocene age of the high-temperature metamorphism. (authors)

  5. THE GLACIER COMPLEXES OF THE MOUNTAIN MASSIFS OF THE NORTH-WEST OF INNER ASIA AND THEIR DYNAMICS

    Directory of Open Access Journals (Sweden)

    Kirill Chistyakov

    2011-01-01

    Full Text Available The subject of this paper is the glaciation of the mountain massifs Mongun-Taiga, Tavan-Boghd-Ola, Turgeni-Nuru, and Harhira-Nuru. The glaciation is represented mostly by small forms that sometimes form a single complex of dome-shaped peaks. According to the authors, the modern glaciated area of the mountain massifs is 21.2 km2(Tavan-Boghd-Ola, 20.3 km2 (Mongun-Taiga, 42 km2 (Turgeni-Nuru, and 33.1 km2 (Harhira-Nuru. The area of the glaciers has been shrinking since the mid 1960’s. In 1995–2008, the rate of reduction of the glaciers’ area has grown considerably: valley glaciers were rapidly degrading and splitting; accumulation of morainic material in the lower parts of the glaciers accelerated. Small glaciers transformed into snowfields and rock glaciers. There has been also a degradation of the highest parts of the glaciers and the collapse of the glacial complexes with a single zone of accumulation into isolated from each other glaciers. Reduced snow cover area has led to a rise in the firn line and the disintegration of a common accumulation area of the glacial complex. In the of the Mongun-Taiga massif, in 1995–2008, the firn line rose by 200–300 m. The reduction of the glaciers significantly lagged behind the change in the position of the accumulation area boundary. In the past two years, there has been a significant recovery of the glaciers that could eventually lead to their slower degradation or stabilization of the glaciers in the study area.

  6. Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian Basin from Medina County, Ohio, through southwestern and south-central Pennsylvania to Hampshire County, West Virginia

    Science.gov (United States)

    Ryder, Robert T.; Harris, Anita G.; Repetski, John E.; revised and digitized by Crangle, Robert D.

    2003-01-01

    A 275-mi-long restored stratigraphic cross section from Medina County, Ohio, through southwestern and south-central Pennsylvania to Hampshire County, W. Va., provides new details on Cambrian and Ordovician stratigraphy in the central Appalachian basin and the structure of underlying Precambrian basement rocks. From west to east, the major structural elements of the block-faulted basement in this section are (1) the relatively stable, slightly extended craton, which includes the Wooster arch, (2) the fault-controlled Ohio-West Virginia hinge zone, which separates the craton from the adjoining Rome trough, (3) the Rome trough, which consists of an east-facing asymmetric graben and an overlying sag basin, and (4) a positive fault block, named here the South-central Pennsylvania arch, which borders the eastern margin of the graben part of the Rome trough. Pre-Middle Ordovician structural relief on Precambrian basement rocks across the down-to-the-west normal fault that separates the Rome trough and the adjoining South-central Pennsylvania arch amounted to between 6,000 and 7,000 ft. The restored cross section shows eastward thickening of the Cambrian and Ordovician sequence from about 3,000 ft near the crest of the Wooster arch at the western end of the section to about 5,150 ft at the Ohio-West Virginia hinge zone adjoining the western margin of the Rome trough to about 19,800 ft near the depositional axis of the Rome trough. East of the Rome trough, at the adjoining western edge of the South-central Pennsylvania arch, the Cambrian and Ordovician sequence thins abruptly to about 13,500 ft and then thins gradually eastward across the arch to about 12,700 ft near the Allegheny structural front and to about 10,150 ft at the eastern end of the restored section. In general, the Cambrian and Ordovician sequence along this section consists of four major lithofacies that are predominantly shallow marine to peritidal in origin. In ascending stratigraphic order, the lithofacies

  7. Why is the central area of the Alburni Mts in southern Italy so full of caves?

    Science.gov (United States)

    Cafaro, Simona; Gueguen, Erwan; Parise, Mario; Schiattarella, Marcello

    2016-04-01

    The Alburni Mts represent one of the most important karst area of southern Italy, with about 250 registered caves. Located in the southern Apennines, they constitute an impressive carbonate massif within the Mesozoic-Cenozoic Campania-Lucania platform. The study area is located inside the National Park of Cilento, Vallo di Diano and Alburni, and is bounded by two major rivers: the Calore and Tanagro rivers. This area has been repeatedly affected during Pleistocene by the activity of a regional, partly blind, NW-SE-striking fault system responsible for several huge earthquakes. The massif is limited to the north by an important normal fault zone (Alburni Line), whereas towards the E-SE it is bounded by a complex fault system linking the Alburni Mts to the Maddalena Mts across the Auletta basin and the Vallo di Diano valley. The entire massif is structured by NW-SE trending transtensional faults delimiting half-graben basins, and offset also by NE-SW trending faults. In particular, structural and geomorphological data have shown that the central area of the calcareous ridge is characterized by a relative structural low rhombic-shaped in planimetric view. Approximately 180 karst caves of the known 250, including some of the most significant from a speleological viewpoint, are located in this area. Is this simply due to repeated exploration activity in the last 25 years in this specific sector or might it be related to geological matter? New morphometric and structural data suggest that a relevant transversal structure, consisting of a complex NE-SW fault system, responsible for the genesis of the downthrown area in the central sector of the flat-topped ridge, was able to create the tectonic framework for the development of a great number of karst caves which present peculiar features and hydrological behaviour due to such structural controls. In this contribution we present and discuss these data, aimed at contributing to increase the knowledge on an area of sure

  8. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V). The origin of these typically discordant ore deposits remains as enigmatic as the magmatic evolution of their host rocks. The deposits clearly have a magmatic origin, hosted by an age-constrained unique suite of rocks that likely are the consequence of a particular combination of tectonic circumstances, rather than any a priori temporal control. Principal ore minerals are ilmenite and hemo-ilmenite (ilmenite with extensive hematite exsolution lamellae); occurrences of titanomagnetite, magnetite, and apatite that are related to this deposit type are currently of less economic importance. Ore-mineral paragenesis is somewhat obscured by complicated solid solution and oxidation behavior within the Fe-Ti-oxide system. Anorthosite suites hosting these deposits require an extensive history of voluminous plagioclase crystallization to develop plagioclase-melt diapirs with entrained Fe-Ti-rich melt rising from the base of the lithosphere to mid- and upper-crustal levels. Timing and style of oxide mineralization are related to magmatic and dynamic evolution of these diapiric systems and to development and movement of oxide cumulates and related melts. Active mines have developed large open pits with extensive waste-rock piles, but

  9. Subduction metamorphism in the Himalayan ultrahigh-pressure Tso Morari massif: An integrated geodynamic and petrological modelling approach

    Science.gov (United States)

    Palin, Richard M.; Reuber, Georg S.; White, Richard W.; Kaus, Boris J. P.; Weller, Owen M.

    2017-06-01

    The Tso Morari massif is one of only two regions where ultrahigh-pressure (UHP) metamorphism of subducted crust has been documented in the Himalayan Range. The tectonic evolution of the massif is enigmatic, as reported pressure estimates for peak metamorphism vary from ∼2.4 GPa to ∼4.8 GPa. This uncertainty is problematic for constructing large-scale numerical models of the early stages of India-Asia collision. To address this, we provide new constraints on the tectonothermal evolution of the massif via a combined geodynamic and petrological forward-modelling approach. A prograde-to-peak pressure-temperature-time (P-T-t) path has been derived from thermomechanical simulations tailored for Eocene subduction in the northwestern Himalaya. Phase equilibrium modelling performed along this P-T path has described the petrological evolution of felsic and mafic components of the massif crust, and shows that differences in their fluid contents would have controlled the degree of metamorphic phase transformation in each during subduction. Our model predicts that peak P-T conditions of ∼2.6-2.8 GPa and ∼600-620 ∘C, representative of 90-100 km depth (assuming lithostatic pressure), could have been reached just ∼3 Myr after the onset of subduction of continental crust. This P-T path and subduction duration correlate well with constraints reported for similar UHP eclogite in the Kaghan Valley, Pakistan Himalaya, suggesting that the northwest Himalaya contains dismembered remnants of what may have been a ∼400-km-long UHP terrane comparable in size to the Western Gneiss Region, Norway, and the Dabie-Sulu belt, China. A maximum overpressure of ∼0.5 GPa was calculated in our simulations for a homogeneous crust, although small-scale mechanical heterogeneities may produce overpressures that are larger in magnitude. Nonetheless, the extremely high pressures for peak metamorphism reported by some workers (up to 4.8 GPa) are unreliable owing to conventional thermobarometry

  10. Sm-Nd age of ultrabasite-basite massifs of east part of Baikal-Mujya ophiolite belt

    International Nuclear Information System (INIS)

    Izokh, A.Eh.; Gibsher, A.S.; Zhuravlev, D.Z.; Balykin, P.A.

    1998-01-01

    Two stratified ultrabasite-basite massifs of the Urals mountains were selected for isotope-geochemical studies. The intrusives, related to plutonic members of the island-arc associations, were used for dating. The Sm-Nd method indicated that one more belt, namely the Vend belt, is taking shape in the Baikal-Mujya tectonic collage alongside with the later Riphean (pre-Baikal) episubconduction belt of stratified intrusives [ru

  11. Seismic fabric and 3-D structure of the southwestern intracontinental Palmyride fold belt, Syria

    Energy Technology Data Exchange (ETDEWEB)

    Chaimov, T.A.; Barazangi, M. (Cornell Univ., Ithaca, NY (United States)); Al-Saad, D.; Sawaf, T.; Khaddour, M. (Ministry of Petroleum and Mineral Resources, Damascus (Syrian Arab Republic))

    1993-12-01

    The Palmyride fold belt, a 400 x 100 km transpressive belt in central Syria that is the northeastern arm of the Syrian arc, is the result of late Mesozoic and Cenozoic inversion of a late Paleozoic and Mesozoic, northeast-trending, linear intracontinental basin located within the northern Arabian platform. The southwestern Palmyrides, near the Dead Sea transform fault system and the Anti-Lebanon mountains, are characterized by short wavelength (5--10 km) en echelon folds separated by small intermontane basins that developed mainly in the Neogene to Holocene. A new three-dimensional data cube, 60 x 70 x 10 km, generated on a Landmark Graphics workstation and based on approximately 700 km of two-dimensional seismic reflection profiles, elucidates the structure of the upper 10 km of the crust in the southwestern Palmyrides. Visualization of the subsurface structure, which is represented by a prominent Upper Cretaceous reflection surface in the data cube, is augmented by topographical and Bouguer gravity data of the same region. Preexisting discontinuities, probable normal fault relicts of the Mesozoic Palmyride rift, likely controlled the development of individual Neogene thrusts. The new subsurface image shows important structural features not identified in outcrop. Short, west-northwest-trending transcurrent (or transfer) faults like the short, en echelon northeast-trending thrust faults and blind thrusts of the Palmyrides. A pervasive regional decollment is not observed, even though Triassic evaporites host local detachments. Unlike topographic relief, which only roughly resembles subsurface structures, the Bouguer gravity signature of the southwestern Palmyrides closely mimics underlying shallow geologic structures both on a large ([approximately]50 km wavelength) and a small ([approximately]5--10 km wavelength) scale. The structural analysis and many other recent studies of the region indicate minor right-lateral shear coupled with compression in the Palmyrides.

  12. Southwestern Power Administration Combined Financial Statements, 2006-2009

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-09-01

    We have audited the accompanying combined balance sheets of the Southwestern Federal Power System (SWFPS), as of September 30, 2009, 2008, 2007, and 2006, and the related combined statements of revenues and expenses, changes in capitalization, and cash flows for the years then ended. As described in note 1(a), the combined financial statement presentation includes the hydroelectric generation functions of another Federal agency (hereinafter referred to as the generating agency), for which Southwestern Power Administration (Southwestern) markets and transmits power. These combined financial statements are the responsibility of the management of Southwestern and the generating agency. Our responsibility is to express an opinion on these combined financial statements based on our audits. We conducted our audits in accordance with auditing standards generally accepted in the United States of America. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the combined financial statements are free of material misstatement. An audit includes consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of Southwestern and the generating agency’s internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the combined financial statements, assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall combined financial statement presentation. We believe that our audits provide a reasonable basis for our opinion. In our opinion, the combined financial statements referred to above present fairly, in all material respects, the respective financial position of the Southwestern Federal Power

  13. Upper crustal structure of the northern part of the Bohemian ­Massif in ­rel­ation­ t­o geological, potential field data and new deep seismic data (Eger/Ohře Rift, Central Europe)

    Czech Academy of Sciences Publication Activity Database

    Skácelová, Z.; Mlčoch, B.; Novotný, Miroslav; Mrlina, Jan

    2011-01-01

    Roč. 39, č. 1 (2011), s. 1-18 ISSN 0303-4534 R&D Projects: GA AV ČR IAA300460602; GA MŽP SB/630/3/02 Institutional research plan: CEZ:AV0Z30120515 Keywords : upper crustal structure * Bohemian Massif * Eger/Ohře Rift * Saxothuringian Zone * Teplá-Barrandian Unit * Moldanubian Zone Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  14. Southwestern Federal Power System 1995 Financial Statement audit under the Chief Financial Officers Act (WR-FC-96-02)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-22

    The Southwestern Federal Power System encompasses the operation of 24 hydroelectric power plants by the U.S. Army Corps of Engineers and the marketing of power and energy from those plants by the Southwestern Power Administration of the U.S. Department of Energy. To integrate the operation of these hydroelectric generating plants and to transmit power from the dams to its customers, Southwestern Power Administration (Southwestern) maintains 2,220 kilometers (1,380 miles) of high-voltage transmission lines, 24 substations, and 46 microwave and VHF radio sites. Southwestern`s headquarters are in Tulsa, Oklahoma; its dispatch center is in Springfield, Missouri; and its maintenance crews are based in Jonesboro, Arkansas, in Gore and Tupelo, Oklahoma, and in Springfield, Missouri. Three offices - Power Marketing and Delivery, Maintenance, and Administration and Rates - are responsible for meeting Southwestern`s mission. Twelve of the 24 generating plants are scheduled directly by Southwestern, and a total of 19 contribute to the interconnected system operations. Generation at the five remaining projects (Denison, Narrows, Sam Rayburn, Whitney, and Willis) is used to serve specific customer loads. At the end of fiscal year 1995, Southwestern marketed power and energy to 10 generation and transmission cooperatives, one distribution cooperative, three military installations, 44 municipal utilities, and three municipal utility joint-action agencies. One of the joint-action agencies has its own allocation of power from Southwestern; the other two serve 33 municipal utilities to whom Southwestern has allocated power. The total number of power allocation customers is 92. Additionally, excess energy is occasionally sold to non-allocation utilities.

  15. Feasibility study of wind-generated electricity for rural applications in southwestern Ohio

    Science.gov (United States)

    Kohring, G. W.

    The parameters associated with domestic production of wind generated electricity for direct use by small farms and rural homes in the southwestern Ohio region are discussed. The project involves direct utility interfaced electricity generation from a horizontal axis, down-wind, fixed pitch, wind powered induction generator system. Goals of the project are to determine: the ability to produce useful amounts of domestic wind generated electricity in the southwestern Ohio region; economic justification for domestic wind generated electrical production; and the potential of domestic wind generated electricity for reducing dependence on non-renewable energy resources in the southwestern Ohio region.

  16. The Oldest Granites of Russia: Paleoarchean (3343 Ma) Subalkali Granites of the Okhotsk Massif

    Science.gov (United States)

    Kuzmin, V. K.; Bogomolov, E. S.; Glebovitskii, V. A.; Rodionov, N. V.

    2018-02-01

    The Paleoarchean age (3.34 Ga) of subalkali granite magmatism first established for the Kukhtui uplift of the Okhotsk Massif suggests a formation time of the mature continental K-rich crust in this region as early as the Paleoarchean. According to the geological structural, mineralogical-geochemical, geochronological, and isotopic-geochemical data, the Kukhtui uplift can be considered as the most ancient Paleoarchean province in Russia: the ancient consolidation core of the sialic protocrust of the Okhotsk-Omolon Craton.

  17. The ophiolite massif of Kahnuj (western Makran, Southern Iran): new geological and geochronological data

    International Nuclear Information System (INIS)

    Kananian, A.; Juteau, Th.; Bellon, H.; Darvishzadeh, A.; Sabzehi, M.; Whitechurch, H.; Ricou, L.E.

    2001-01-01

    The ophiolite massif of Kahnuj (600 km 2 ) consists, from bottom to top, of layered gabbros, isotropic gabbros and ouralite gabbros, agmatites of dioritic to plagio-granitic composition, a sheeted dyke complex and lastly a basaltic pillow lava unit. Amphiboles from gabbros were dated ( 40 K- 40 Ar ages) between 156 and 139 Ma and the agmatites are nearly contemporaneous. Potassic granitic veins dated at 93-88 Ma are related to the development of the Ganj arc complex. (authors)

  18. The topographic signature of Quaternary tectonic uplift in the Ardennes massif (Western Europe)

    Science.gov (United States)

    Sougnez, N.; Vanacker, V.

    2011-04-01

    Geomorphic processes that produce and transport sediment, and incise river valleys are complex; and often difficult to quantify over longer timescales of 103 to 105 y. Morphometric indices that describe the topography of hill slopes, valleys and river channels have commonly been used to compare morphological characteristics between catchments and to relate them to hydrological and erosion processes. This study aims to analyze the link between tectonic uplift rates and landscape morphology based on slope and channel morphometric indexes. To achieve this objective, we selected 10 catchments of about 150 to 250 km2 across the Ardennes Massif (a Palaeozoic massif of NW Europe, principally located in Belgium) that cover various tectonic domains with uplift rates ranging from about 0.06 to 0.20 mm yr-1 since mid-Pleistocene times. The morphometric analysis indicates that the slope and channel morphology of third-order catchments is not yet in topographic steady-state, and exhibits clear convexities in slope and river profiles. Our analysis indicates that the fluvial system is the main driver of topographic evolution and that the spatial pattern of uplift rates is reflected in the distribution of channel steepness and convexity. The spatial variation that we observe in slope and channel morphology between the 10 third-order catchments suggests that the response of the fluvial system was strongly diachronic, and that a transient signal of adjustment is migrating from the Meuse valley towards the Ardennian headwaters.

  19. Current state of uranium exploration in central Colombia: Regional perspective and selected case studies

    International Nuclear Information System (INIS)

    Moreno, G.; Perez, A.

    2014-01-01

    The Colombian Geological Survey has been working in a regional exploration program focus on the ancients massifs of the Eastern Cordillera. The general geology distribution in these massifs (Santander and Quetame) includes a core of meta sedimentary to medium grade metamorphic rocks of pellitic origin presumed to be of Cambro – Ordovician age, intruded by Ordovician age plutons that grade from granodiorite to quartz diorite. This igneous – metamorphic core is unconformable overlain by a Devonian age sedimentary cover that includes conglomerates of continental origin, black mudstone of marine origin and red sandstones of deltaic environments with some calcareous intervals. In the Santander Massif a sequence of continental red beds of Jurasic age is present and in the Zapatoca (Santander) area contains uranium. In the Santander Massif, mineral exploration in an area on 1300 km"2 with 1235 sample locations, gives average uranium values of 5.44 ppm, an a maximum of 20 ppm, located in Ordovician plutonic rocks. In the Quetame Massif, mineral exploration in an area on 1000 km"2 with 1274 samples locations, gives average uranium values of 6.13 ppm, and a maximum of 2763 ppm, located in Devonian to Carboniferous sedimentary rocks. In the Paipa area, 140 kilometers from Bogota, the Colombian Geological Survey has undertaken exploratory drilling. As a result there is an anomalous area of 500 m"2 with values of 2000 ppm uranium and rare earth associations has been identified. The volcanic system has been studied by several authors and is important for its location and extention. In recent years, exploration by private companies was reactivated. In early 2000 several junior companies such as KPS/Energentia Resources Inc., Mega Uranium, U3O8 Corp, Energentia Resources Inc., Blue Sky Uranium Corp, Sprott Resource Corp. and UrAmericaLtd and began exploratory work in Colombia. The Berlin project, located in the central mountain range, is perhaps the most developed in the

  20. Monazite and zircon as major carriers of Th, U, and Y in peraluminous granites: examples from the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Breiter, Karel

    2016-01-01

    Roč. 110, č. 6 (2016), s. 767-785 ISSN 0930-0708 R&D Projects: GA ČR GA14-13600S Institutional support: RVO:67985831 Keywords : zircon * monazite * granites * trace elements * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.236, year: 2016

  1. Condition and Organization of Everyday Life in the Military Units of the Southwestern, Stalingrad and Don fronts (1942–1943

    Directory of Open Access Journals (Sweden)

    Tatiana P. Khlynina

    2015-03-01

    Full Text Available The article is devoted to various aspects of the condition and organization of the everyday life of military units of the Southwestern, Stalingrad and Don fronts in 1942–1943 years. The looks of the questions of food and clothing supplies, ensure domestic needs and recreation. At the base of the article are documents of the Central Archive of the Ministry of Defense of the Russian Federation, recorded memories participants in the events of that time, published sources.

  2. Migration patterns and movements of sandhill cranes wintering in central and southwestern Louisiana

    Science.gov (United States)

    King, Sammy L.; Pierce, Aaron R.; Hersey, Kent R.; Winstead, Nicholas; Hartup, Barry K.

    2010-01-01

    In this study we trapped wintering sandhill cranes (Grus canadensis) in Louisiana and fitted them with satellite transmitters to determine their migration routes. Four of the 6 sandhill cranes with validated locations and a terminus point used the Central Flyway for spring migration; 2 of these 4 (the only 2 for which we have data) also used the Central Flyway for fall migration. Two of the 6 birds used the Mississippi Flyway for spring migration. The results of this study suggest that reintroduced whooping cranes (G. americana) that intermix and migrate with sandhill cranes that winter in Louisiana may enter the Central Flyway. In addition, the Mississippi Flyway is a viable option to use as a migration route for whooping cranes if they are reintroduced in Louisiana.

  3. Lateral displacement of crustal units relative to underlying mantle lithosphere: Example from the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Babuška, Vladislav; Plomerová, Jaroslava

    2017-01-01

    Roč. 48, December (2017), s. 125-138 ISSN 1342-937X R&D Projects: GA ČR GAP210/12/2381; GA MŠk(CZ) LD15029; GA MŠk LM2010008; GA MŠk(CZ) LM2015079 Institutional support: RVO:67985530 Keywords : Bohemian Massif * Teplá-Barrandian mantle lithosphere * Zone Erbendorf-Vohenstrauss * Jáchymov Fault Zone Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 6.959, year: 2016

  4. Tourist Traffic In The Aconcagua Massif Area

    Directory of Open Access Journals (Sweden)

    Marek Aneta

    2015-09-01

    Full Text Available The aim of the article is an analysis of tourist traffic in the Aconcagua massif, one of the most popular peaks of the Seven Summits. On the basis of statistical data, the tourist traffic was analysed in a temporal and spatial perspective. The applied data made it possible to capture the dynamics of visits in the period 2000/2001 – 2012/2013 and with a breakdown into months, which helped analyse the tourist traffic in this area. In each of the analysed periods, January dominates. Data concerning the origin of tourists according to countries and continents, their age, gender and type of mountaineering activity were also taken into account. Most tourists came from Argentina, the USA and Germany. These are people of age groups 21–30 (33% and 31–40 (31%. Men account for over 75% of visitors. The favourite mountaineering activity is climbing (about 60%. Aconcagua has invariably been a very popular peak among tourists and climbers. It is a place for training and acclimatisation for alpinists, participating in Himalayan expeditions and climbers collecting peaks of the Seven Summits.

  5. Deciphering the Variscan tectonothermal overprint and deformation partitioning in the Cadomian basement of the Teplá-Barrandian unit, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Hajná, J.; Žák, J.; Kachlík, V.; Chadima, Martin

    2012-01-01

    Roč. 101, č. 7 (2012), s. 1855-1873 ISSN 1437-3254 Institutional support: RVO:67985831 Keywords : Avalonian-Cadomian belt * Bohemian Massif * Shear zone * Teplá-Barrandian unit * transpression * Variscan orogeny Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.261, year: 2012

  6. SHOCK-CLOUD INTERACTION AND PARTICLE ACCELERATION IN THE SOUTHWESTERN LIMB OF SN 1006

    Energy Technology Data Exchange (ETDEWEB)

    Miceli, M.; Orlando, S.; Bocchino, F. [INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy); Acero, F. [ORAU/NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States); Dubner, G. [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Decourchelle, A., E-mail: miceli@astropa.unipa.it [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, F-91191 Gif-sur-Yvette (France)

    2014-02-20

    The supernova remnant SN 1006 is a powerful source of high-energy particles and evolves in a relatively tenuous and uniform environment despite interacting with an atomic cloud in its northwestern limb. The X-ray image of SN 1006 reveals an indentation in the southwestern part of the shock front and the H I maps show an isolated (southwestern) cloud, having the same velocity as the northwestern cloud, whose morphology fits perfectly in the indentation. We performed spatially resolved spectral analysis of a set of small regions in the southwestern nonthermal limb and studied the deep X-ray spectra obtained within the XMM-Newton SN 1006 Large Program. We also analyzed archive H I data, obtained by combining single-dish and interferometric observations. We found that the best-fit value of N {sub H} derived from the X-ray spectra significantly increases in regions corresponding to the southwestern cloud, while the cutoff energy of the synchrotron emission decreases. The N {sub H} variation corresponds perfectly with the H I column density of the southwestern cloud, as measured from the radio data. The decrease in the cutoff energy at the indentation clearly reveals that the back side of the cloud is actually interacting with the remnant. The southwestern limb therefore presents a unique combination of efficient particle acceleration and high ambient density, thus being the most promising region for γ-ray hadronic emission in SN 1006. We estimate that such emission will be detectable with the Fermi telescope within a few years.

  7. SHOCK-CLOUD INTERACTION AND PARTICLE ACCELERATION IN THE SOUTHWESTERN LIMB OF SN 1006

    International Nuclear Information System (INIS)

    Miceli, M.; Orlando, S.; Bocchino, F.; Acero, F.; Dubner, G.; Decourchelle, A.

    2014-01-01

    The supernova remnant SN 1006 is a powerful source of high-energy particles and evolves in a relatively tenuous and uniform environment despite interacting with an atomic cloud in its northwestern limb. The X-ray image of SN 1006 reveals an indentation in the southwestern part of the shock front and the H I maps show an isolated (southwestern) cloud, having the same velocity as the northwestern cloud, whose morphology fits perfectly in the indentation. We performed spatially resolved spectral analysis of a set of small regions in the southwestern nonthermal limb and studied the deep X-ray spectra obtained within the XMM-Newton SN 1006 Large Program. We also analyzed archive H I data, obtained by combining single-dish and interferometric observations. We found that the best-fit value of N H derived from the X-ray spectra significantly increases in regions corresponding to the southwestern cloud, while the cutoff energy of the synchrotron emission decreases. The N H variation corresponds perfectly with the H I column density of the southwestern cloud, as measured from the radio data. The decrease in the cutoff energy at the indentation clearly reveals that the back side of the cloud is actually interacting with the remnant. The southwestern limb therefore presents a unique combination of efficient particle acceleration and high ambient density, thus being the most promising region for γ-ray hadronic emission in SN 1006. We estimate that such emission will be detectable with the Fermi telescope within a few years

  8. Genetic variation in the endangered Southwestern Willow Flycatcher

    Science.gov (United States)

    Busch, Joseph; Miller, Mark P.; Paxton, E.H.; Sogge, M.K.; Keim, Paul

    2000-01-01

    The Southwestern Willow Flycatcher (Empidonax traillii extimus) is an endangered Neotropical migrant that breeds in isolated remnants of dense riparian habitat in the southwestern United States. We estimated genetic variation at 20 breeding sites of the Southwestern Willow Flycatcher (290 individuals) using 38 amplified fragment length polymorphisms (AFLPs). Our results suggest that considerable genetic diversity exists within the subspecies and within local breeding sites. Statistical analyses of genetic variation revealed only slight, although significant, differentiation among breeding sites (Mantel's r = 0.0705, P UPGMA cluster analysis of the AFLP markers indicates that extensive gene flow has occurred among breeding sites. No one site stood out as being genetically unique or isolated. Therefore, the small level of genetic structure that we detected may not be biologically significant. Ongoing field studies are consistent with this conclusion. Of the banded birds that were resighted or recaptured in Arizona during the 1996 to 1998 breeding seasons, one-third moved between breeding sites and two-thirds were philopatric. Low differentiation may be the result of historically high rangewide diversity followed by recent geographic isolation of breeding sites, although observational data indicate that gene flow is a current phenomenon. Our data suggest that breeding groups of E. t. extimus act as a metapopulation.

  9. Perceptions of social and environmental changes in a Mediterranean forest during the last 100 years: the Gavarres Massif.

    Science.gov (United States)

    Rodríguez-Carreras, Roser; Ubeda, Xavier; Outeiro, Luís; Asperó, Francesc

    2014-06-01

    During the last century the landscape of the mid-Mediterranean mountains has undergone major transformations. The precipitous decline in the economic viability of forest products has engendered ever-thickening forests and agricultural lands have reverted to forest land cover. The related exodus of existing inhabitants since 1960 has led to new styles of occupancy: residential and touristic land uses have emerged while the primary and secondary sectors have largely disappeared. The object of the present study is to review how these transformations have developed in a specific area of north-eastern of Catalonia, known as the Gavarres Massif. The study applies a qualitative approach, based on interviews with stakeholders including active members of the local community and others who utilize or visit the area, all of whom are representatives of different social groups with a wide range of interests and points of view with regard to the massif. The information collected from the perspectives and opinions of the participants is coupled with objective data about the area. The result of this investigation is a rich variety of perceptions on landscape and social transformation and its current functional dynamics. Analyzing the information obtained allows us to understand the fact that the disappearance of the rural world is directly related to the collapse of an entire economic system that relied on the environment. In this study, two divergent points of view arise, one which supports recovering past landscapes and another which favours managing changes, conserving the existing landscape. Proposals for the current and future territorial management of Les Gavarres are presented. The diversity of opinions which emerges with regard to managing necessary changes in the massif emphasizes the importance of increased social dialogue. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. 44/40Ca and 87Sr/86Sr isotopes as tracers of silicate weathering in small catchments of the Massif Central, France

    Science.gov (United States)

    Négrel, Philippe; Guerrot, Catherine; Millot, Romain; Petelet-Giraud, Emmanuelle; Bullen, Thomas

    2013-04-01

    We present calcium stable isotope and strontium radiogenic isotope data for soils and sediments developed on volcanic and igneous rocks forming small catchments in the Massif Central (France). Measurements of 44/40Ca isotope ratios (44/40Ca measured by the double spike method on TIMS and normalized to the value for seawater Ca in delta units) in rocks, sediments and soils from silicate catchments (e.g. granite and basalts) together with 87Sr/86Sr isotope ratios permit an examination of the relationships of these isotope systematics during weathering of silicate rocks. We have analysed the granite, weathered granite (arene) and saprolite, sediment and soil overlying the granite on one hand and the basanite, sediment and soil overlying the basanite on the other. The main bedrock in the volcanic zone (e.g. Allanche catchment) is 11 to 2.5 Ma basanite (nephelinitic to leucitic basalts) having SiO2 between 41-45 wt. %, Na2O + K2O bank have 87Sr/86Sr ratios greater than that of the arene with values increasing in the sediment from the surface down to soil. The 87Sr/86Sr vs. Rb/Sr variation observed in the volcanic area likewise confirms the weathering of low 87Sr/86Sr, low Rb/Sr phases in the bedrock, and there is a linear increase in 87Sr/86Sr and Rb/Sr ratios from those in the sediment up to the values observed in the soils. In the volcanic area, the basanite bedrock has 44/40Ca = -0.94 ± 0.05‰ (n = 7), while the soils and sediments have 44/40Ca of -0.75 to -1.13‰ and -0.79 to -1.01‰, respectively. These results suggest that Ca isotopes are not strongly fractionated during weathering of the basalt. The granite whole-rock has 44/40Ca of -1.29‰, while the soil and sediments have 44/40Ca of -1.93 to -2.07‰ and -1.98 to -2.81‰, respectively, with values decreasing as the Ca content decreases. The 44/40Ca ratios of arene, soil and sediment are similar to or less than that of K- feldspar, reflecting complete loss of the relatively heavy Ca from plagioclase and

  11. The topographic signature of Quaternary tectonic uplift in the Ardennes massif (Western Europe

    Directory of Open Access Journals (Sweden)

    N. Sougnez

    2011-04-01

    Full Text Available Geomorphic processes that produce and transport sediment, and incise river valleys are complex; and often difficult to quantify over longer timescales of 103 to 105 y. Morphometric indices that describe the topography of hill slopes, valleys and river channels have commonly been used to compare morphological characteristics between catchments and to relate them to hydrological and erosion processes. This study aims to analyze the link between tectonic uplift rates and landscape morphology based on slope and channel morphometric indexes. To achieve this objective, we selected 10 catchments of about 150 to 250 km2 across the Ardennes Massif (a Palaeozoic massif of NW Europe, principally located in Belgium that cover various tectonic domains with uplift rates ranging from about 0.06 to 0.20 mm yr−1 since mid-Pleistocene times. The morphometric analysis indicates that the slope and channel morphology of third-order catchments is not yet in topographic steady-state, and exhibits clear convexities in slope and river profiles. Our analysis indicates that the fluvial system is the main driver of topographic evolution and that the spatial pattern of uplift rates is reflected in the distribution of channel steepness and convexity. The spatial variation that we observe in slope and channel morphology between the 10 third-order catchments suggests that the response of the fluvial system was strongly diachronic, and that a transient signal of adjustment is migrating from the Meuse valley towards the Ardennian headwaters.

  12. Water-level trends and potentiometric surfaces in the Nacatoch Aquifer in northeastern and southwestern Arkansas and in the Tokio Aquifer in southwestern Arkansas, 2014–15

    Science.gov (United States)

    Rodgers, Kirk D.

    2017-09-20

    The Nacatoch Sand in northeastern and southwestern Arkansas and the Tokio Formation in southwestern Arkansas are sources of groundwater for agricultural, domestic, industrial, and public use. Water-level altitudes measured in 51 wells completed in the Nacatoch Sand and 42 wells completed in the Tokio Formation during 2014 and 2015 were used to create potentiometric-surface maps of the two areas. Aquifers in the Nacatoch Sand and Tokio Formation are hereafter referred to as the Nacatoch aquifer and the Tokio aquifer, respectively.Potentiometric surfaces show that groundwater in the Nacatoch aquifer flows southeast toward the Mississippi River in northeastern Arkansas. Groundwater flow direction is towards the south and southeast in Hempstead, Little River, and Nevada Counties in southwestern Arkansas. An apparent cone of depression exists in southern Clark County and likely alters groundwater flow from a regional direction toward the depression.In southwestern Arkansas, potentiometric surfaces indicate that groundwater flow in the Tokio aquifer is towards the city of Hope. Northwest of Hope, an apparent cone of depression exists. In southwestern Pike, northwestern Nevada, and northeastern Hempstead Counties, an area of artesian flow (water levels are at or above land surface) exists.Water-level changes in wells were identified using two methods: (1) linear regression analysis of hydrographs from select wells with a minimum of 20 years of water-level data, and (2) a direct comparison between water-level measurements from 2008 and 2014–15 at each well. Of the six hydrographs analyzed in the Nacatoch aquifer, four indicated a decline in water levels. Compared to 2008 measurements, the largest rise in water levels was 35.14 feet (ft) in a well in Clark County, whereas the largest decline was 14.76 ft in a well in Nevada County, both located in southwestern Arkansas.Of the four hydrographs analyzed in the Tokio aquifer, one indicated a decline in water levels, while

  13. The Dilemma and Solutions for the Conflicts between Equality and Excellence in the Massification of Higher Education in Taiwan

    Science.gov (United States)

    Hsiou-Huai, Wang

    2012-01-01

    Equality and excellence are two core values underlying many educational endeavors; however, they are often in conflict and controversy. This article intends to examine the dilemma created by such controversies in the context of massification of higher education in Taiwan and attempt to provide solutions from both the theoretical and policy…

  14. Plio-Pleistocene basanitic and melilititic series of the Bohemian Massif: K-Ar ages, major/trace element and Sr–Nd isotopic data

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Ackerman, Lukáš; Balogh, K.; Hegner, E.; Jelínek, E.; Pécskay, Z.; Přichystal, A.; Upton, B. G. J.; Zimák, J.; Foltýnová, R.

    2013-01-01

    Roč. 73, č. 4 (2013), s. 429-450 ISSN 0009-2819 Institutional support: RVO:67985831 Keywords : Bohemian Massif * Plio-Pleistocene * Basanite * Melilitite * K-Ar age * Magmatism * Sr–Nd isotopes Subject RIV: DD - Geochemistry Impact factor: 1.397, year: 2013

  15. A new species of Pristimantis (Anura, Craugastoridae) from the Cajas Massif, southern Ecuador

    Science.gov (United States)

    Sánchez-Nivicela, Juan C.; Celi-Piedra, Elvis; Posse-Sarmiento, Valentina; Urgiles, Verónica L.; Yánez-Muñoz, Mario; Cisneros-Heredia, Diego F.

    2018-01-01

    Abstract A new species of Pristimantis is described from the highland paramos on the eastern slopes of the Cajas Massif, southern Andes of Ecuador, at 3400 m. This new species is characterized by having a distinctive reddish color, cutaneous macroglands in suprascapular region and surfaces of arm and legs, and by lacking dentigerous processes of vomers. The cutaneous macroglands are similar to those exhibited by several species of the Pristimantis orcesi group, and may suggest a close phylogenetic relationship. The new species could be a latitudinal substitution of Pristimantis orcesi in the southern Andes of Ecuador. PMID:29713233

  16. Development of a Comprehensive Plan for Scientific Research, Exploration, and Design: Creation of an Underground Radioactive Waste Isolation Facility at the Nizhnekansky Rock Massif

    International Nuclear Information System (INIS)

    Jardine, L J

    2005-01-01

    ISTC Partner Project No.2377, ''Development of a General Research and Survey Plan to Create an Underground RW Isolation Facility in Nizhnekansky Massif'', funded a group of key Russian experts in geologic disposal, primarily at Federal State Unitary Enterprise All-Russian Design and Research Institute of Engineering Production (VNIPIPT) and Mining Chemical Combine Krasnoyarsk-26 (MCC K-26) (Reference 1). The activities under the ISTC Partner Project were targeted to the creation of an underground research laboratory which was to justify the acceptability of the geologic conditions for ultimate isolation of high-level waste in Russia. In parallel to this project work was also under way with Minatom's financial support to characterize alternative sections of the Nizhnekansky granitoid rock massif near the MCC K-26 site to justify the possibility of creating an underground facility for long-term or ultimate isolation of radioactive waste (RW) and spent nuclear fuel (SNF). (Reference 2) The result was a synergistic, integrated set of activities several years that advanced the geologic repository site characterization and development of a proposed underground research laboratory better than could have been expected with only the limited funds from ISTC Partner Project No.2377 funded by the U.S. DOE-RW. There were four objectives of this ISTC Partner Project 2377 geologic disposal work: (1) Generalize and analyze all research work done previously at the Nizhnekansky granitoid massif by various organizations; (2) Prepare and issue a declaration of intent (DOI) for proceeding with an underground research laboratory in a granite massif near the MCC K-26 site. (The DOI is similar to a Record of Decision in U.S. terminology). (3) Proceeding from the data obtained as a result of scientific research and exploration and design activities, prepare a justification of investment (JOI) for an underground research laboratory in as much detail as the available site characterization

  17. Le Massif du Taburno-Camposauro, une montagne calcaire en position de charnière à l'échelle de l'Apennin méridional (Italie du Sud

    Directory of Open Access Journals (Sweden)

    Bruno Comentale

    2010-03-01

    Full Text Available Le massif du Taburno-Camposauro, bloc calcaire tectoniquement soulevé, occupe une position de charnière dans l'Apennin méridional, du fait du morcellement orographique qui permet l'établissement d'une communication entre les deux versants, tyrrhénien et adriatique, de la péninsule italienne. En complément de ce morcellement redevable à la néotectonique plio-pléistocène en extension, le massif juxtapose de vigoureux escarpements de faille et des topographies sommitales à aplanissements partiels, ultérieurement karstifiées. En replaçant ce massif dans le contexte géomorphologique régional, et en en soulignant les nombreuses analogies avec le massif voisin du Matese, ce travail conduit une analyse microtectonique des escarpements de faille associés à des déformations de brèches, alors que le lien génétique entre ces dernières et les topographies sommitales fait l'objet d'une discussion.The Taburno-Camposauro limestone faulted block has a key location between tyrrhenian and adriatic sides of the Southern Apennines, because of the relief disruption due to extensional Plio-Pleistocene neotectonics. From this, results a contrasted landscape, with prior gentle erosional landsurfaces (Upper Miocene-Early Pliocene? subsequently disrupted by huge fault scarps. After a microtectonic analysis along these fault scarps, also considering the deformation of breccia – which are regarded as genetically linked with the erosional landsurfaces shaping –, the discussion deals with the regional geomorphic pattern, mainly the nearest Matese mountain.

  18. Cambrian trilobites with Siberian affinities, southwestern Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, A.R.; Egbert, R.M.; Sullivan, R.; Knoth, J.S.

    1985-02-01

    Cambrian trilobites occur in two levels (about 7 m apart) in the core of a large, complex anticlinal structure in the area between the Taylor Mountains and the Hoholitna River in southwestern Alaska. The lower collection contains Erbia, Macannaia (a species close to Soviet forms described as Pagetia ferox Lermontova), two species of Kootenia (including one perhaps cospecific with forms from the central Brooks range), and several species of ptychoparioid trilobites. It is clear that biogeographic affinities are with the transitional facies of the eastern Siberian platform and the south Siberian foldbelt. In Soviet terms, the age of the collection falls in a disputed interval called latest Early Cambrian (Tojonian) by some authors, and earliest Middle Cambrian (Amgan) by others. In North American terms, Macannaia is known only from early Middle Cambrian beds. The younger collection contains abundant agnostids, a variety of conocoryphids, Paradoxides, and several species of ptychoparioid trilobites. This is an assemblage of undoubted late Middle Cambrian age, comparable to faunas described from the Maya State of the Siberian platform and the Paradoxides paradoxissimus Stage of the Baltic region. Both faunas are from ocean-facing or outer shelf environments. None of the key non-agnostid or non-pagetiid elements have been seen previously in deposits of Cambrian North America.

  19. Contrasting evidence of Holocene ice margin retreat, south-western Greenland

    DEFF Research Database (Denmark)

    Levy, L. B.; Larsen, N. K.; Davidson, T. A.

    2017-01-01

    Constraining the Greenland Ice Sheet's (GrIS) response to Holocene climate change provides calibrations for ice sheet models that hindcast past ice margin fluctuations. Ice sheet models predict enhanced ice retreat in south-western Greenland during the middle Holocene; however, few geological...... observations corroborating the extensive retreat are available. We present new data from lake sediment cores from the Isua region, south-western Greenland, which provide constraints on Holocene fluctuations of the GrIS margins. Our data indicate that the main GrIS margin was 30 km west of its present...

  20. Seven Global Goals. 2013 annual report, Southwestern Power Administration

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-09-01

    For over 70 years, Southwestern has marketed and delivered reliable, renewable, and affordable hydropower, partnering with Federal power stakeholders and others in the industry to make sure the lights stay on. This kind of effective, efficient, and cost conscious operation is made possible only by hard work and dedication. Southwestern employees work individually and as a team to meet seven comprehensive agency goals that touch on all aspects of the agency’s operations. Dubbed the “Seven Global Goals” by Administrator Chris Turner, these objectives identify specific, measurable targets that support Southwestern’s mission and reinforce its responsibilities toward its customers and the Nation.

  1. Factors influencing woodlands of southwestern North Dakota

    Science.gov (United States)

    Michele M. Girard; Harold Goetz; Ardell J. Bjugstad

    1987-01-01

    Literature pertaining to woodlands of southwestern North Dakota is reviewed. Woodland species composition and distribution, and factors influencing woodland ecosystems such as climate, logging, fire, and grazing are described. Potential management and improvement techniques using vegetation and livestock manipulation have been suggested.

  2. Late Cretaceous and Cenozoic dynamics of the Bohemian Massif inferred from the paleostress history of the Lusatian Fault Belt

    Czech Academy of Sciences Publication Activity Database

    Coubal, Miroslav; Málek, Jiří; Adamovič, Jiří; Štěpančíková, Petra

    2015-01-01

    Roč. 87, July 1 (2015), s. 26-49 ISSN 0264-3707 R&D Projects: GA ČR GAP210/12/0573 Institutional support: RVO:67985831 ; RVO:67985891 Keywords : paleostress * fault kinematics * Lusatian Fault Belt * Elbe fault system * Bohemian Massif * Alpine foreland Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.926, year: 2015

  3. Behavior of trace elements in quartz from plutons of different geochemical signature: A case study from the Bohemian Massif, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Breiter, Karel; Ackerman, Lukáš; Svojtka, Martin; Müller, A.

    175/176, 15 August (2013), s. 54-67 ISSN 0024-4937 R&D Projects: GA ČR GAP210/10/1105 Institutional support: RVO:67985831 Keywords : Quartz * trace elements * granites * fractionation * Bohemian Massif Subject RIV: DD - Geochemistry Impact factor: 3.654, year: 2013

  4. Origin of the Okrouhlá Radouň episyenite-hosted uranium deposit, Bohemian Massif, Czech Republic: fluid inclusion and stable isotope constraints

    Czech Academy of Sciences Publication Activity Database

    Dolníček, Z.; René, Miloš; Hermannová, S.; Prochaska, W.

    2014-01-01

    Roč. 49, č. 4 (2014), s. 409-425 ISSN 0026-4598 R&D Projects: GA MŠk ME10083 Institutional support: RVO:67985891 Keywords : Bohemian Massif * Uranium mineralization * Episyenite * Fluid inclusions Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.561, year: 2014

  5. Forest responses to increasing aridity and warmth in the southwestern United States

    Science.gov (United States)

    Williams, A.P.; Allen, Craig D.; Millar, C.I.; Swetnam, T.W.; Michaelsen, J.; Still, C.J.; Leavitt, Steven W.

    2010-01-01

    In recent decades, intense droughts, insect outbreaks, and wildfires have led to decreasing tree growth and increasing mortality in many temperate forests. We compared annual tree-ring width data from 1,097 populations in the coterminous United States to climate data and evaluated site-specific tree responses to climate variations throughout the 20th century. For each population, we developed a climate-driven growth equation by using climate records to predict annual ring widths. Forests within the southwestern United States appear particularly sensitive to drought and warmth. We input 21st century climate projections to the equations to predict growth responses. Our results suggest that if temperature and aridity rise as they are projected to, southwestern trees will experience substantially reduced growth during this century. As tree growth declines, mortality rates may increase at many sites. Increases in wildfires and bark-beetle outbreaks in the most recent decade are likely related to extreme drought and high temperatures during this period. Using satellite imagery and aerial survey data, we conservatively calculate that ≈2.7% of southwestern forest and woodland area experienced substantial mortality due to wildfires from 1984 to 2006, and ≈7.6% experienced mortality associated with bark beetles from 1997 to 2008. We estimate that up to ≈18% of southwestern forest area (excluding woodlands) experienced mortality due to bark beetles or wildfire during this period. Expected climatic changes will alter future forest productivity, disturbance regimes, and species ranges throughout the Southwest. Emerging knowledge of these impending transitions informs efforts to adaptively manage southwestern forests.

  6. Characteristics of Intracrater Thermal Anomalies in Southwestern Margaritifer Terra

    Science.gov (United States)

    McDowell, M. L.; Hamilton, V. E.

    2005-03-01

    We use thermophysical properties, albedo, short wavelength emissivity, composition, and geomorphology to understand the formation of anomalously warm intracrater deposits in southwestern Margaritifer Terra.

  7. U/Pb dating: brioverian age of the Erquy series (Armorican massif, France)

    International Nuclear Information System (INIS)

    Cocherie, A.; Chantraine, J.; Egal, E.; Fanning, C.M.; Dabard, M.P.; Paris, F.; Le Herisse, A.

    2001-01-01

    New U/Pb analyses obtained with a high-resolution ion microprobe (SHRIMP) fix an age of 608 ± 7 Ma for spilites of the Erquy series, in Cadomian rocks of the Armorican massif, France. This Neo-proterozoic age re-integrates this unit into the Brioverian, the age it was initially assigned to. A Rb/sr whole-rock dating in the 1970's had undermined the regional Cadomian model, by suggesting an Ordovician age for these rocks; this was apparently further supported by the discovery of organic remains, interpreted as Paleozoic micro-fossils. The reassessment of this paleontologic attribution and the new isotope dating are a final confirmation of the age of this series. (authors)

  8. Research on Structure Innovation of Agricultural Organization in China’s Southwestern Mountainous Regions

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taking agricultural organization in China’s southwestern mountainous regions as research object,on the basis of analysis of the status quo of agricultural organization development in China’s southwestern mountainous regions,we use related theoretical knowledge on economics and organization science,we probe into the process of innovation and mechanism of action concerning the structure of agricultural organization in China’s southwestern mountainous regions over the past 30 years.Finally we draw several general conclusions regarding structure innovation of agricultural organization in China’s southwestern mountainous regions as follows:first,the structure innovation of agricultural organization,a gradual process,proceeds ceaselessly along with ongoing progress and development of agriculture,and in this process,farmers always play a fundamental role;second,the structure innovation of agricultural organization is affected by many factors,and government institutional arrangement and change in market conditions is undoubtedly the most critical factor;third,the probable evolving direction of structure innovation of agricultural organization includes internal differentiation of the same form of agricultural organization,association of different forms of agricultural organization,and emergence of other forms of agricultural organization.

  9. Winter Counter-Wind Transport in the Inner Southwestern Yellow Sea

    Science.gov (United States)

    Wu, Hui; Gu, Jinghua; Zhu, Ping

    2018-01-01

    Coastal currents generally flow downshelf with land on the right side (Northern Hemisphere) under the geostrophic balance, and are often strengthened by downwelling-favorable winds. However, the recent mooring observation in the inner southwestern Yellow Sea showed that coastal transport direction can be substantially changed by tidal forcing. In the survey, the tidal-averaged transports at two out of three sites remained northward (i.e., in the upshelf direction) and opposite the downwelling-favorable northerly wind, except during a brief neap tide period. Numerical experiments showed that the incoming Poincaré wave tide from the East China Sea plays a key role in forming this counter-wind transport system. This tidal wave produces a shoreward tidal stress south of 33.5°N in the inner southwestern Yellow Sea, driving an upshelf transport under the Earth's rotation. Counterpropagating tidal waves from the East China Sea and the northern Yellow Sea collide in coastal water in 32.5-34°N, which produce a standing tidal wave and therefore a mean sea-surface setup with alongshore and cross-shelf scales of both >100 km. This sea-surface setup causes an alongshore sea surface gradient, which veers the upshelf transport to the offshore direction under geostrophic balance. The strong tidal current increases the tidal-mean bottom resistance in the SCW, thus reduces the wind-driven current to a magnitude smaller than the tide-induced residual transport velocity. Therefore, upshelf transport persists in the inner southwestern Yellow Sea, and the Changjiang River Estuary becomes a major source area for the inner southwestern Yellow Sea.

  10. 78 FR 65703 - Notice of Availability of the Idaho and Southwestern Montana Greater Sage-Grouse Draft Land Use...

    Science.gov (United States)

    2013-11-01

    ...] Notice of Availability of the Idaho and Southwestern Montana Greater Sage-Grouse Draft Land Use Plan... Environmental Impact Statement (EIS) for managing Greater Sage- Grouse (GRSG) in the Idaho and Southwestern... Southwestern Montana Greater Sage-Grouse Draft LUP Amendments/Draft EIS by any of the following methods: Email...

  11. Boundaries of mantle–lithosphere domains in the Bohemian Massif as extinct exhumation channels for high-pressure rocks

    Czech Academy of Sciences Publication Activity Database

    Babuška, Vladislav; Plomerová, Jaroslava

    2013-01-01

    Roč. 23, č. 3 (2013), s. 973-987 ISSN 1342-937X R&D Projects: GA ČR GA205/07/1088; GA ČR GAP210/12/2381; GA AV ČR IAA300120709 Institutional research plan: CEZ:AV0Z30120515 Keywords : Bohemian Massif * mantle lithosphere domains * fossil olivine fabric * high pressure Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 8.122, year: 2013

  12. Long Wavelenth Subsidence of Western Europe during Late Eocene-Oligocene (38-23 Ma): Mantle Dynamic Effect?

    Science.gov (United States)

    Guillocheau, Francois; Robin, Cécile; Bessin, Paul

    2015-04-01

    Western Europe (France, southern Britain, southern Belgium, western Germany) is subsiding during Late Eocene to Oligocene (38-23 Ma) as suggested by the growth of numerous small sedimentary basins mainly filled by lacustrine deposits with some brackish to marine deposits. This large-scale subsidence is coeval with the early stage of the so-called Oligocene rifts (in fact Late Bartonian to Rupelian): Lower Rhinegraben, Bresse, Limagnes. The subsiding domain extends from Cornwall to the Rhine Graben including the Armorican Massif, the southern Paris Basin, the northern Aquitaine Basin, the French Central Massif, the Ardennes-Eifel… This subsidence occurred at a period of global sea level fall and then an eustatic component cannot explain (1) the accommodation space creation and (2) the marine floding with a paroxysm during Early Oligocene times (Armorican Massif, ?Ardennes, French Massif central). This marine flooding also indicate that the relief of the Hercynian basement was less elevated and smoother than today. Some of those small "basins" were interpreted as little rifts, but new mapping (e.g. Puy-en-Velay or Forez Plain in the French Massif central) or new geophysical data (e.g. Rennes Basin in the Armorican massif) suggest that no faults control those basins or that they result from post-depositional collapses. This long wavelength subsidence is at the scale of the mantle dynamic. Possible mantle mechanisms and the relationships with the "Oligocene" rifts and the North Sea inversion will be discussed.

  13. Evidence for partial melting of eclogite from the Moldanubian Zone of the Bohemian Massif, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Miyazaki, T.; Nakamura, D.; Tamura, A.; Svojtka, Martin; Arai, S.; Hirajima, T.

    2016-01-01

    Roč. 111, č. 6 (2016), s. 405-419 ISSN 1345-6296 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100131203 Program:Program interní podpory projektů mezinárodní spolupráce AV ČR Institutional support: RVO:67985831 Keywords : partial melting * eclogite * leucocratic pockets * Bohemian Massif * Moldanubian Zone Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.409, year: 2016

  14. Comprenhensive Program of Engineering and Geologic Surveys for Designing and Constructing Radioactive Waste Storage Facilities in Hard Rock Massifs

    International Nuclear Information System (INIS)

    Gupalo, T.; Milovidov, V.; Prokopoca, O.; Jardine, L.

    2002-01-01

    Geological, geophysical, and engineering-geological research conducted at the 'Yeniseisky' site obtained data on climatic, geomorphologic, geological conditions, structure and properties of composing rock, and conditions of underground water recharge and discharge. These results provide suficient information to make an estimate of the suitability of locating a radioactive waste (RW) underground isolation facility at the Nizhnekansky granitoid massif.

  15. Structure, emplacement, and tectonic setting of Late Devonian granitoid plutons in the Teplá–Barrandian unit, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Žák, J.; Kratinová, Zuzana; Trubač, J.; Janoušek, V.; Sláma, Jiří; Mrlina, Jan

    2011-01-01

    Roč. 100, č. 7 (2011), s. 1477-1495 ISSN 1437-3254 R&D Projects: GA AV ČR KJB300120702 Institutional research plan: CEZ:AV0Z30120515; CEZ:AV0Z30130516 Keywords : Bohemian Massif * Teplá-Barrandian unit * Variscan orogeny * granite * pluton * subduction Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.342, year: 2011

  16. Field and geochemical constraints on the relationship between the Apoteri basalts (northern Brazil, southwestern Guyana) and the Central Atlantic Magmatic Province

    Science.gov (United States)

    Pinto, Viter M.; Santos, João Orestes S.; Ronchi, Luiz H.; Hartmann, Léo A.; Bicudo, Carlos Alberto; de Souza, Vladimir

    2017-11-01

    In northern Brazil, Roraima state and southwestern Guyana, basalt flows characterized by inflated pahoehoe structure occur along the margins of the Tacutu Rift Valley, dykes intrude the Paleoproterozoic basement close to the boundary of the rift system with concordant, NE-trend. The dykes and flows belong to Apoteri magmatism. New field, geochemical data (major, trace and rare-earth elements) and chemical stratigraphy of the Apoteri magmatism indicate petrographic and chemical homogeneity characteristic of continental tholeiitic basalts. The basalt flows of Morro Redondo and Nova Olinda sites show two distinct chemical groups: a) the lower flows with intermediate TiO2 content (ITi group) ranging from 1.09 to 1.41 wt%, MgO (5.64-6.46 wt%) and Ni (43-53 ppm) contents; and b) the upper flows with lower TiO2 content (LTi group) = 0.75 to 0.78 wt%, higher MgO = 7.95-8.85 wt% and Ni = 105-115 ppm. The two magma types share many characteristics in high field strength elements (HFSE) and rare earth elements (REE), but in detail significant differences exist in REE ratios, e.g. (La/Yb)N of ∼4.0 for ITi and 3.2 for LTi and this may be explained by fractional crystallization. The chemical compositions of the Apoteri dykes are similar the ITi group analyses, suggesting that they have the same origin. The La/Ba versus La/Nb diagram is indicative of large ion lithophile elements (LILE) enrichment and LILE/HFSE fractionation in the mantle source, and the data favor a dominant subcontinental lithospheric mantle (SCLM) component in the origin of the Apoteri flows and dykes. These data show consistent similar chemical characteristics and correspond to other tholeiitic flows from the large Central Atlantic Magmatic Province (CAMP), especially eastern USA.

  17. Rhenium-osmium isotopes in pervasively metasomatized mantle xenoliths from the Bohemian Massif and implications for the reliability of Os model ages

    Czech Academy of Sciences Publication Activity Database

    Kochergina, Y. V.; Ackerman, Lukáš; Erban, V.; Matusiak-Malek, M.; Puziewicz, J.; Halodová, P.; Špaček, P.; Trubač, J.; Magna, T.

    2016-01-01

    Roč. 430, July 15 (2016), s. 90-107 ISSN 0009-2541 Institutional support: RVO:67985831 Keywords : Bohemian Massif * depletion age * Ohře/Eger rift * Os isotopes * peridotite xenolith * Re-Os * sub-continental lithospheric mantle Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.347, year: 2016

  18. Nannofossils in upper quaternary bottom sediments of back-arc basins in the southwestern Pacific

    Science.gov (United States)

    Dmitrenko, O. B.

    2015-05-01

    The analysis of calcareous nannoplankton assemblages in bottom sediments sampled during Cruise 21 of the R/V Akademik Mstislav Keldysh in three areas located in back-arc basins of the southwestern Pacific (western Woodlark in the Solomon Sea, Manus in the Bismarck Sea, Central Lau) reveal that they belong to the Emiliania huxleyi Acme Zone, the most detailed one in the Gartner's scale of 1977. The content of coccoliths and their taxonomic composition indicate warm subtropical-tropical conditions. Long cores demonstrate a decrease in species diversity reflecting the transition from the cold late Pleistocene to the Holocene. The changes in species diversity and presence/absence of thermophilic representatives indicate transformation of depositional environments with unstable conditions in the water column and bottom layer, seismic activity, and widely developed processes of sediment redistribution and reworking.

  19. Coeval interaction between magmas of contrasting composition (Late Carboniferous-Early Permian Santa Eulália-Monforte massif, Ossa-Morena Zone): field relations and geochronological constraints

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, M.F.; Gama, C.; Rodríguez, C.

    2017-07-01

    The Santa Eulália-Monforte massif is a post-kinematic Late Carboniferous-Early Permian calc-alkaline composite massif (LC-EP) located in the Ossa-Morena Zone (OMZ, Portugal). This paper examines the field relationships between pinkish granites and mafic-intermediate rocks from the external ring of this massif and presents new U-Pb zircon age determinations. The estimated 206Pb/238U ages, 297±4Ma for the pinkish granite and 303±3Ma for a gabbro-diorite point to a short time interval between the crystallization of both magmas. At outcrop scale, contacts of the mafic-intermediate rocks with the host pinkish granite are sharp and corroborate this age relationship, but do not justify why the host-enclave contacts often has curved and irregular shapes, indicating liquid-liquid interaction. A full analysis of the distribution of U-Pb zircon ages and respective Th/U ratios suggests that the compositionally distinct magmas were roughly contemporaneous. The obtained ages also fit the LC-EP Iberian calc-alkaline suite that was formed contemporaneously to the development of the Iberian-Armorican Arc and when the Paleotethyan oceanic Plate subducted under the Eurasian active margin. Taking this geodynamic setting as a reference, the LC-EP Iberian calc-alkaline magmatism can be interpreted as most probably related to the Cimmerian cycle instead of the traditionally accepted model that ascribe a closer connection of this magmatism with the Variscan cycle. The Santa Eulália-Monforte massif is a post-kinematic Late Carboniferous-Early Permian calc-alkaline composite massif (LC-EP) located in the Ossa-Morena Zone (OMZ, Portugal). This paper examines the field relationships between pinkish granites and mafic-intermediate rocks from the external ring of this massif and presents new U-Pb zircon age determinations. The estimated 206Pb/238U ages, 297±4Ma for the pinkish granite and 303±3Ma for a gabbro-diorite point to a short time interval between the crystallization of both

  20. Coeval interaction between magmas of contrasting composition (Late Carboniferous-Early Permian Santa Eulália-Monforte massif, Ossa-Morena Zone): field relations and geochronological constraints

    International Nuclear Information System (INIS)

    Pereira, M.F.; Gama, C.; Rodríguez, C.

    2017-01-01

    The Santa Eulália-Monforte massif is a post-kinematic Late Carboniferous-Early Permian calc-alkaline composite massif (LC-EP) located in the Ossa-Morena Zone (OMZ, Portugal). This paper examines the field relationships between pinkish granites and mafic-intermediate rocks from the external ring of this massif and presents new U-Pb zircon age determinations. The estimated 206Pb/238U ages, 297±4Ma for the pinkish granite and 303±3Ma for a gabbro-diorite point to a short time interval between the crystallization of both magmas. At outcrop scale, contacts of the mafic-intermediate rocks with the host pinkish granite are sharp and corroborate this age relationship, but do not justify why the host-enclave contacts often has curved and irregular shapes, indicating liquid-liquid interaction. A full analysis of the distribution of U-Pb zircon ages and respective Th/U ratios suggests that the compositionally distinct magmas were roughly contemporaneous. The obtained ages also fit the LC-EP Iberian calc-alkaline suite that was formed contemporaneously to the development of the Iberian-Armorican Arc and when the Paleotethyan oceanic Plate subducted under the Eurasian active margin. Taking this geodynamic setting as a reference, the LC-EP Iberian calc-alkaline magmatism can be interpreted as most probably related to the Cimmerian cycle instead of the traditionally accepted model that ascribe a closer connection of this magmatism with the Variscan cycle. The Santa Eulália-Monforte massif is a post-kinematic Late Carboniferous-Early Permian calc-alkaline composite massif (LC-EP) located in the Ossa-Morena Zone (OMZ, Portugal). This paper examines the field relationships between pinkish granites and mafic-intermediate rocks from the external ring of this massif and presents new U-Pb zircon age determinations. The estimated 206Pb/238U ages, 297±4Ma for the pinkish granite and 303±3Ma for a gabbro-diorite point to a short time interval between the crystallization of both

  1. Pattern of corrosive ingestion in southwestern Saudi Arabia

    International Nuclear Information System (INIS)

    AlBinali Ali M; AlShehri, Mohammed A; AlFifi, Suliman H; Abdelmoneim, Ismail; Shomrani, Ali S

    2009-01-01

    Ingested corrosive material is a major pediatric emergency all over the world. The corrosive material can cause damage to the digestive tract, ranging from minor injury to strictures, and sometimes even death. We aimed to review the pattern of corrosive ingestion in children who had been admitted to Aseer Central Hospital in the Southwestern region of Saudi Arabia. This is a retrospective study of all children who had been admitted with a history of corrosive ingestion to Aseer Central Hospital over a period of five years period from 1990 to 1995. The records of 72 patients (38 males and 34 females) were reviewed. The data included age, sex, time lapse till admission, action taken by parents, presenting symptoms, general management given to the child, barium study, endoscopy, and the postcorrosive ingestion outcome of the child. The mean age of the pediatric patients was 28 + - 20 months. Different types of corrosives were encountered. The most common type was 5.25% hypochlorite in 36 patients (50%), kerosene in 12 patients (16.7%), caustic soda in nine patients (12.5%), hydrogen chloride and N-alkyl dimethyl benzyl ammonium chloride (HC and ADB) in eight patients (11.1%), and other material in seven patients (9.7%). Endoscopy was done in 30 patients (31.7%), 14 of whom were abnormal. Barium swallow was performed in 11 patients; five of them showed strictures that required frequent dilatation whereas one needed interposition surgery. Corrosive injury is still a major pediatric emergency among young children. It carries a major risk of complications (mainly stricture) and requires standardized management based on evidence-based medicine. (author)

  2. Hydrothermal alterations and O, H, C isotopic characterization of fluids and minerals in uraniferous massif of Saint Sylvestre (France). Extension to other French intragranitic uranium deposits

    International Nuclear Information System (INIS)

    Turpin, L.

    1984-05-01

    Petrographical, mineralogical, geochemical and stable isotope ( 18 O/ 16 O, D/H, 13 C/ 12 C) studies have been performed on the leucogranitic massif of St Sylvestre (Limousin, Massif Central francais), particularly on the different hydrothermal alterations. The oxygen isotope geochemistry of granites confirms the unicity of the different facies and their sialic origin (delta 18 O whole rocks = +11.0 +- 0.5 per mill), with a major contribution of detritic sediments rich in organic matter and poor in carbonate (delta 13 C magm. CO 2 = -10.6 per mill). Late lamprophyres have a deep-seated origin (delta 18 O = + 6 per mill). The pervasive chloritization of granitic biotites occurs during the convective circulation of a fluid of meteoric origin, at temperatures around 350-450 0 C. The chemical composition of chlorite which is buffered by that of biotite and the large 18 O-shift of fluid towards high delta values indicate that water-rock ratio was not very high. Chloritization takes place in high permeability zones. In regions where porosity is generally low, fluids are ''canalised'' in localised micro-fissured zones. Very high water/rock ratios lead to the dissolution of quartz, and the formation of the ''feldspathic episyenite'' alteration facies. The isotopic features of this fluid (delta 18 O approximately - 8 per mill, deltaD approximately - 50 per mill) indicate an elevated altitude. An isotopically similar fluid is responsible for the later ''micaceous episyenite'' alteration facies, found in fractured zones. Mixing of this fluid with a sedimentary fluid (delta 18 O approximately + 10 per mill, deltaD approximately - 30 per mill, delta 13 C approximately - 18 per mill) yielded the conditions necessary for the deposit of primary economic ore. Such fluids, sedimentary or metamorphic in origin, have been recognized in most hercynian intragranitic U and Sn-W deposits [fr

  3. Upland hardwood habitat types in southwestern North Dakota

    Science.gov (United States)

    Michele M. Girard; Harold Goetz; Ardell J. Bjugstad

    1985-01-01

    The Daubenmire habitat type method was used to classify the upland hardwood draws of southwestern North Dakota. Preliminary data analysis indicates there are four upland habitat types: Fraxinus pennsylvanica/Prunus virginiana; F. pnnseanica-Ulmus americana/P. virginiana; Populus...

  4. The timberline as result of the interactions among forest, abiotic environment and human activity in the Babia Gora massif, Western Carpathians

    Science.gov (United States)

    Lajczak, Adam

    2016-04-01

    The timberline is one of the clearest and most easily discernible boundaries in nature (Troll 1973). Among the existing conceptual models clarifying the complex nature of the relationship between the timberline and the environment and human impact, the fullest seems to be the one presented by K. Holtmeier (2009). The quoted author comprehensively characterizes the timberline, taking into account its course, appearance and ecological characteristics. The aim of the work is to quantitatively assess the factors influencing the course of timberline and its changes over the last ca. 400 years in the Babia Góra massif (1725 m a.s.l.), the highest flysch ridge in the Western Carpathians, which is formed as an asymmetric ridge of kuesta type. Forests mainly in the upper montane zone have preserved their natural character in many areas. Old spruce tree growths are a particular advantage of the Babia Góra Mt., being there on the predominant section of the altitude zone of the timberline. In the rest of this zone, spruce forests have been under a direct or indirect influence of changes resulting from grazing with its 400-year history and forestry taking place about 100 years ago. The 60 m difference between the average altitude of the timberline on the northern (1335 m a.s.l.) and the southern slope (1395 m a.s.l.) on the Babia Góra Mt. can be explained with climatic conditions of these areas. The average gradient of the slope within the timberline ecotone on the southern slope of the massif is by 100 smaller, and the amount of solar energy delivered during the growing season is 40% higher (960 kWh/m2) than on the northern slope. The higher position of the timberline on the windward southern slope is favored by the dominant winds from S-W sector, thinner snow cover and earlier melting due to the lower precipitation on the slope and also due to the winnowing of snow onto the steep northern slope of the ridge. On the southern slope of the ridge there are no larger snow

  5. Some geophysical constraints to dynamic processes in the Southwestern Mediterranean

    Directory of Open Access Journals (Sweden)

    P. Chiozzi

    1996-06-01

    Full Text Available The total tectonic subsidence, thermal state and seismotectonic regime have been analysed to better constrain the dynamic processes which originated the basins of the Southwestern Mediterranean. It is argued that backarc extension and oceanic spreading are the possible and main processes which took place within a compressional framework, driven by the interaction between the African and European plates. As inferred by both subsidence and heat-flux data, in the central part of the Algerian-Balearic basin the crust is oceanic, 20 Ma old on average, originated by a spreading phase, which also affected the Ligurian-Provençal basin. The Alboran basin, which is underlain by stretched continental crust, shows an intermediate seismic activity and a few deep events, explainable by a gravitational collapse of cold lithosphere. After a review of the most recent geodynamical hypotheses, an evolutionary scheme is attempted envisaging the lateral continental escape of the Gibraltar arc. Within a convergent tectonic framework, some lithospheric material could translate almost perpendicular to the convergence direction, and undergo a lateral subduction process, secondary to the main boundary between plates.

  6. The Krásná Hora, Milešov, and Příčovy Sb-Au ore deposits, Bohemian Massif: mineralogy, fluid inclusions, and stable isotope constraints on the deposit formation

    Science.gov (United States)

    Němec, Matěj; Zachariáš, Jiří

    2018-02-01

    The Krásná Hora-Milešov and Příčovy districts (Czech Republic) are the unique examples of Sb-Au subtype orogenic gold deposits in the Bohemian Massif. They are represented by quartz-stibnite veins and massive stibnite lenses grading into low-grade, disseminated ores in altered host rocks. Gold postdates the stibnite and is often replaced by aurostibite. The ore zones are hosted by hydrothermally altered dikes of lamprophyres (Krásná Hora-Milešov) or are associated with local strike-slip faults (Příčovy). Formation of Sb-Au deposits probably occurred shortly after the main gold-bearing event (348-338 Ma; Au-only deposits) in the central part of the Bohemian Massif. Fluid inclusion analyses suggest that stibnite precipitated at 250 to 130 °C and gold at 200 to 130 °C from low-salinity aqueous fluids. The main quartz gangue hosting the ore precipitated from the same type of fluid at about 300 °C. Early quartz-arsenopyrite veins are not associated with the Sb-Au deposition and formed from low-salinity, aqueous-carbonic fluid at higher pressure and temperature ( 250 MPa, 400 °C). The estimated oxygen isotope composition of the ore-bearing fluid (4 ± 1‰ SMOW; based on post-ore calcite) suggests its metamorphic or mixed magmatic-metamorphic origin and excludes the involvement of meteoric water. Rapid cooling of warm hydrothermal fluids reacting with "cold" host rock was probably the most important factor in the formation of both stibnite and gold.

  7. Using Telepresence to Connect and Engage Classes and the Public in the Exploration of Tamu Massif, the World's Largest Single Volcano

    Science.gov (United States)

    Nanez-James, S. E.; Sager, W.

    2016-02-01

    Research published in 2013 showed that TAMU Massif, the largest mountain in the Shatsky Rise oceanic plateau, located approximately 1500 kilometers east of Japan, is the "World's Largest Single Volcano." This claim garnered widespread public interest and wonder concerning how something so big could remain so mysterious in the 21st century. This disconnect highlights the fact that oceans are still widely unexplored, especially the middle of the deep ocean. Because there is so much interest in TAMU Massif, a diverse outreach team lead by chief scientist Dr. William Sager from the University of Houston in partnership with the Texas State Aquarium and the Schmidt Ocean Institute (SOI) conducted a multifaceted ship-to-shore outreach project that included secondary school students, formal and informal educators, university students and professors, the aquarium and museum audience, and the general public. The objective was to work in conjunction with SOI and various other partners, including the Texas Regional Collaborative, the Aquarium of the Pacific, and the Houston Museum of Natural Science, to promote science and ocean literacy while inspiring future scientists - especially those from underserved and underrepresented groups - through ocean connections. Participants were connected through live ship-to-shore distance learning broadcasts of ongoing marine research and discovery of TAMU Massif aboard the R/V Falkor, allowing audiences to participate in real-time research and apply real world science to curriculum in the classrooms. These ship-to-shore presentations connected to existing curriculums and standards, lessons, and career interests of the students and educators with special teacher events and professional development workshops conducted from aboard the R/V Falkor.

  8. Transit traverse in Missouri, 1900-1937. Part 7, Central Missouri, 1902-37

    Science.gov (United States)

    Staack, John George

    1940-01-01

    This bulletin, which for convenience is to be published in eight parts, contains the results of all transit traverse* done In Missouri through 1937 by the Geological Survey, United States Department of the Interior, including those heretofore published. (See page X.) Each of the parts deals with one of eight sections into which the State has been divided for this purpose and which have been designated northeastern, northwestern, southeastern, southwestern, central, east-central, south-central, and west-central Missouri. In each part descriptions of the points for which geodetic positions have been determined are listed according to the quadrangles in which the points occur. Results of transit traverse other than that done by the Geological Survey have not been included.Central Missouri, as the term is used in this bulletin and as the subject of part 7 of the bulletin, is that section of the State lying between latitudes 36°00' and 39°30' and between longitudes 92°00' and 93°30'.

  9. Constraints on the origin of gabbroic rocks from the Moldanubian-Moravian units boundary (Bohemian Massif, Czech Republic and Austria)

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Ackerman, Lukáš; Kachlík, V.; Hegner, E.; Balogh, K.; Langrová, Anna; Luna, J.; Fediuk, F.; Lang, M.; Filip, Jiří

    2010-01-01

    Roč. 61, č. 3 (2010), s. 175-191 ISSN 1335-0552 R&D Projects: GA AV ČR IAA3013403; GA AV ČR IAA300130902 Institutional research plan: CEZ:AV0Z30130516 Keywords : gabbroic rocks * geochemistry * Sr-Nd isotopes * K-Ar ages * Moravian Unit * Moldanubian Unit * Bohemian Massif Subject RIV: DD - Geochemistry Impact factor: 0.909, year: 2010

  10. Oster pluton (Central Karelia) - the ancient massif of two-feldspar granites of Baltic Shield

    International Nuclear Information System (INIS)

    Kovalenko, A.V.; Rizvanova, N.G.

    2000-01-01

    Geochronological study of two-feldspar granites forming the Oster pluton in the Central Karelia was performed using the methods of U-Pb- and Sm-Nd-dating. U-Pb isotope data for zircons from granite of the Oster pluton correspond to the age of 2876±21 mln. years, whereas Sm-Nd isotope data obtained for three samples of the garnet correspond to the age varying from 3.0 to 3.5 bln. years. The ancient age of granites of the Oster pluton is explained by the presence of a sufficiently powerful crust in the region by that moment [ru

  11. Seismic refraction technique aplications in the geotechnical characterization of the Cachoeira deposit massif, Caetite, State of Bahia, Brazil

    International Nuclear Information System (INIS)

    Malagutti Filho, W.; Oliveira Braga, T. de.

    1984-01-01

    Geophysical surveys throught the Cachoeira Uranium deposit massif were carried out with the purpose of assisting in the geotechnical characterization for the implantation of the Mining-Industrial Complex projects on the Lagoa Real uranium deposits, Caetite municipality, state of Bahia, Brazil. This study discusses the methodology utilized in the geophysical surveys and their results as well as their applications to the geotechnical characterization as a whole. (D.J.M.) [pt

  12. Multiple fluid sources/pathways and severe thermal gradients during formation of the Jílové orogenic gold deposit, Bohemian Massif, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Zachariáš, J.; Žák, Karel; Pudilová, M.; Snee, L. W.

    2013-01-01

    Roč. 54, October (2013), s. 81-109 ISSN 0169-1368 Institutional research plan: CEZ:AV0Z30130516 Institutional support: RVO:67985831 Keywords : Orogenic gold deposits * Carbon isotopes * Oxygen isotopes * Bismuth * Age * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.383, year: 2013

  13. Use of Digital Elevation Models to understand map landforms and history of the magmatism Khibiny Massif (Kola Peninsula, Russia)

    Science.gov (United States)

    Chesalova, Elena; Asavin, Alex

    2016-04-01

    This work presents an improved geomorphological methodology that uses 3D model of relief, remotely-sensed data, geological, geophysical maps and tools of Geographical Information Systems. On the basis of maps of 1: 50,000 and 1: 200,000 the Digital Elevation model (DEM) of Khibiny massif was developed. We used software ARC / INFO v10.2 ESRI. A DEM was used for analyzing landform by extracting the slope gradient, curvature, valley pro?les, slope, aspect and so on. The results were gradually re?ned from the interpretation of satellite imagery and geological map Geomorphological analysis will allow us to determine spatial regularities in inner massive construction. We try to found areas where gas emissions (CH4/H2) enrich, according to morphometry, geology, tectonic and other environments. The main regional blocks were de?ned by different morphological evidences: impression zone, similar to subsidence caldera; uplift zone, domed area (located in the highest part of massif and zone of intersection of main faults) and others. It says that there are the few stages in the development of the Khibiny massif. There is no common concept of the consequence of intrudes magmatic phases now. And we hope that our geomorphical analysis take a new evidences about this problems. Locations of the blocks' borders (tectonic zones) were recognized by lineament analysis of valleys and tectonic faults presented in relief. Erosion system is represented by valleys of 4 ranks. It inherits the zone of tectonic disturbances 3 groups of faults were recognized: 1) Global lineament system cross whole peninsula - existing before Khibiny massif intrusion; 2) Faults associated with the formation of the intrusive phases sequence and magma differentiation and with later collision history during magma cooling; 3) Crack system related to neotectonic process. We believed that if different magmatic phases intrude in similar tectonic environment, the common spatial system of faults will be formed. Really we

  14. Forecast of promising areas for uranium prospection at the metamorphic Massif of Isla de la Juventud

    International Nuclear Information System (INIS)

    Gongora, L.E.; Macola, E.; Sanchez, J.; Torres, J.C.; Alaminos, C.; LLanes, A.; Morales, M.

    1995-01-01

    A mineralization conceptual model for uranium of the metamorphic Massif of Isla de la Juventud was established taking into account the study of the geological and metallogenic characteristic of the territory. The determined indications of mineralization were plotted on the geological map in order to conform a forecasting map and the selection of 22 hypothetical promising areas was carried out. As result of the field words three really promising areas were selected. A group of exploration techniques needed to evaluate the targets areas is presented

  15. The Then and Now of Reference Conditions in Streams of the Central Plains

    Science.gov (United States)

    Huggins, D.; Angelo, R.; Baker, D. S.; Welker, G.

    2005-05-01

    Models of contemporary and pre-settlement reference conditions were constructed for streams that once drained the tallgrass prairies of Iowa, Nebraska, Kansas and Missouri (e.g. Western Corn Belt Plains ecoregion), and for streams within the heart of the mixed grass prairie (e.g. Southwestern Tablelands ecoregion). Data on watershed, habitat, chemistry and biology compiled for existing reference streams (least or minimally impacted systems) were used to characterize contemporary reference conditions. Contemporary reference conditions within these two prairie regions are contrasted against hypothetical pre-settlement conditions using information from the best streams (upper 25%) of the current reference population, historical accounts, museum records, natural heritage programs, Public Land Survey and current remote sensing data. Similar comparisons were made between historical and current reference conditions for the Southwestern Tablelands located in central Kansas and Oklahoma. Much of this region remains in mixed grass prairie; has limited hydrological alterations (e.g. impoundments, dewatering) and low human and livestock densities. Within the tablelands these factors have preserved reference conditions that resemble historic conditions. Qualitative and quantitative comparisons indicate that many regions within the Central Plains require caution when using "least disturbed" reference streams and conditions to identify regional biological integrity goals relative to the Clean Water Act.

  16. The Nysa-Morava Zone: an active tectonic domain with Late Cenozoic sedimentary grabens in the Western Carpathians' foreland (NE Bohemian Massif)

    Czech Academy of Sciences Publication Activity Database

    Špaček, P.; Bábek, O.; Štěpančíková, Petra; Švancara, J.; Pazdírková, J.; Sedláček, J.

    2015-01-01

    Roč. 104, č. 4 (2015), s. 963-990 ISSN 1437-3254 R&D Projects: GA ČR GAP210/12/0573; GA MŠk LM2010008 Institutional support: RVO:67985891 Keywords : Bohemian Massif * Upper Morava Basin * tectonic evolution * seismicity * sedimentary grabens Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.133, year: 2015

  17. A habitat overlap analysis derived from Maxent for Tamarisk and the South-western Willow Flycatcher

    Science.gov (United States)

    Patricia York; Paul Evangelista; Sunil Kumar; James Graham; Curtis Flather; Thomas Stohlgren

    2011-01-01

    Biologic control of the introduced and invasive, woody plant tamarisk (Tamarix spp, saltcedar) in south-western states is controversial because it affects habitat of the federally endangered South-western Willow Flycatcher (Empidonax traillii extimus). These songbirds sometimes nest in tamarisk where floodplain-level invasion replaces native habitats. Biologic control...

  18. Greetings and Politeness in Doctor-Client Encounters in Southwestern

    Directory of Open Access Journals (Sweden)

    Akin Odebunmi

    2013-05-01

    Full Text Available Doctors and clients sometimes experience interactiveclashes during hospital meetings in South-western Nigerianhospitals because of their divergent culture-constrainedorientation to politeness cues. The goal of this paper is tounpack the discursive elements that characterize interactiveconfluence and divergence in selected consultativeencounters in the hospitals. The findings indicate thatinstitutional and cultural (disalignments occur in respect ofadjacency and non-adjacency pair greetings. In bothgreeting types, face support, threat and stasis are conjointlyco-constituted by doctors and Yoruba clients within theaffordances of the cultural, institutional and situationalcontext of the Southwestern Nigerian hospital setting.Adjacency pair greetings attract mutual interpretingsbetween the parties; interactive disalignments aredifferentially pragmatically accommodated by doctors andclients. In non-adjacency pair greeting, doctors’ threats areco-constituted as appropriate by both parties, theinstitutional power of doctor and shared Western culturalorientation playing significant roles.

  19. La couverture tertiaire du flanc nord du massif du Troodos et de la partie méridionale de la Mésaoria : étude stratigraphique et micropaléontologique The Terciary Sediments of the Northern Flank of the Stroodos Massif and the Southern Part of Mesaoria : Stratigraphic and Micropaleonlogical Study

    Directory of Open Access Journals (Sweden)

    Baroz F.

    2006-11-01

    Full Text Available Le massif pluto-volcanique du Troodos est ceinturé par une importante série sédimentaire le plus souvent à dominante crayeuse dont l'âge va du Maestrichtien au Messinien, époque à laquelle le Troodos émerge. La mer revient en transgression au Pliocène. Après une recherche bibliographique réinterprétant les principaux résultats des travaux antérieurs, une étude pétrographique, micropaléontologique et stratigraphique est réalisée à partir des échantillons recueillis suivant treize profils, sur le flanc N du Troodos et dans la partie méridionale de la Mésaoria. Cette étude montre que les craies résultent de la lithification de boues à Globigérinidés redéposées dans lesquelles les figures de courant et les slumps sont nombreux. Ces dépôts, qui s'organisent en un système progradantà partir du haut fond sous-marin du Troodos, forment sur son flanc N une série condensée présentant de nombreux et souvent spectaculaires hiatus stratigraphiques. Elle caractérise un environnement qui, bathyal inférieur au Maestrichtien-Paléocène, évolue en un milieu de dépôt néritique au Messinien. The plutonic-volcanic Troodos Massif is surrounded by thick sedimentory series, often developed in a predominantly chalky facies ; their age ranges from Maastrichtian to Messinian during which period the Troodos Massif emerged. The sea transgressively returned in Pliocene times. Hoving studied the references which lead to a reinterpretation of the main findings of previous investigations, a petrogrophic, micropaleontological and stratigrophic study of rock somples hos been made, gathered along thirteen profiles on the northern flank of the Troodos Massif and in the southern part of Mesaoria. The study reveals that the chalky resulted from a lithification of redeposited glogigerina oozes, showing numerous current marks and slump structures. These progroding deposits laid down on a Troodos seamount at the time, form a condensed series

  20. Joint inversion of teleseismic P waveforms and surface-wave group velocities from ambient seismic noise in the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Růžek, Bohuslav; Plomerová, Jaroslava; Babuška, Vladislav

    2012-01-01

    Roč. 56, č. 1 (2012), s. 107-140 ISSN 0039-3169 R&D Projects: GA ČR GA205/07/1088; GA AV ČR IAA300120709; GA MŠk LM2010008 Institutional research plan: CEZ:AV0Z30120515 Keywords : receiver function * seismic noise * joint inversion * Bohemian Massif * velocity structure Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.975, year: 2012

  1. Les variations récentes (1975-2000 de l’englacement dans le Massif de l’Aconcagua (Mendoza, Argentine

    Directory of Open Access Journals (Sweden)

    Julie Le Gall

    2008-03-01

    Full Text Available La région de Mendoza est particulièrement vulnérable au réchauffement climatique. Les glaciers du massif de l’Aconcagua ont amorcé un important retrait depuis la fin du Petit Âge de Glace. Or la disparition de ces glaciers risque d’entraîner une modification des régimes hydrologiques qui, jusqu’à présent, se caractérisaient par de hautes eaux estivales. Ce pic estival pourrait à l’avenir être atténué et remettre en cause les stratégies de gestion de la ressource en eau. Nous faisons ici le point sur les variations récentes de l’englacement et tentons de dessiner un scénario prospectif.Mendoza area is highly vulnerable to the global warming. The glaciers of the Aconcagua massif are currently shrinking, this trend of retreat began at the end of the Little Ice Age. The disappearance of glaciers may modify hydrological regimes. The discharge is currently at maximum during summer (related to glacier melt, but the peak discharge may occur during spring (related to snow melt in the next future. In this paper we synthesize the recent variations of the glaciers and propose a pattern of future variations.

  2. Transit traverse in Missouri, 1900-1937. Part 3, East-central Missouri, 1903-37

    Science.gov (United States)

    Staack, John George

    1940-01-01

    This bulletin, which for convenience is to be published in eight parts, contains the results of all transit traverse* done In Missouri through 1937 by the Geological Survey, United States Department of the Interior, including those heretofore published. (See page X.) Each of the parts deals with one of eight sections into which the State has been divided for this purpose and which have been designated northeastern, northwestern, southeastern, southwestern, central, east-central, south-central, and west-central Missouri. In each part descriptions of the points for which geodetic positions have been determined are listed according to the quadrangles in which the points occur. Results of transit traverse other than that done by the Geological Survey have not been included.East-central Missouri, as the term is used in this bulletin and as the subject of part 3 of the bulletin, is that section of the State lying between latitudes 38°00' and 39°15' and east of longitude 92°00'.

  3. Transit traverse in Missouri, 1900-1937. Part 2, South-central Missouri, 1908-37

    Science.gov (United States)

    Staack, John George

    1940-01-01

    This bulletin, which for convenience is to be published in eight parts, contains the results of all transit traverse* done In Missouri through 1937 by the Geological Survey, United States Department of the Interior, including those heretofore published. (See page X.) Each of the parts deals with one of eight sections into which the State has been divided for this purpose and which have been designated northeastern, northwestern, southeastern, southwestern, central, east-central, south-central, and west-central Missouri. In each part descriptions of the points for which geodetic positions have been determined are listed according to the quadrangles in which the points occur. Results of transit traverse other than that done by the Geological Survey have not been included.South-central Missouri, as the term is used in this bulletin and as the subject of part 2 of the bulletin, is that section of the State lying south of latittude, 38°00' and between longitudes 91°15' and 93°00'.

  4. Transit traverse in Missouri, 1900-1937. Part 8, West-central Missouri, 1906-37

    Science.gov (United States)

    Staack, John G.

    1940-01-01

    This bulletin, which for convenience is to be published in eight parts, contains the results of all transit traverse* done In Missouri through 1937 by the Geological Survey, United States Department of the Interior, including those heretofore published. (See page X.) Each of the parts deals with one of eight sections into which the State has been divided for this purpose and which have been designated northeastern, northwestern, southeastern, southwestern, central, east-central, south-central, and west-central Missouri. In each part descriptions of the points for which geodetic positions have been determined are listed according to the quadrangles in which the points occur. Results of transit traverse other than that done by the Geological Survey have not been included.West-central Missouri, as the term is used in this bulletin and as the subject of part 8 of the bulletin, is that section of the State lying between latitudes 38°00' and 39°30' and west of longitude 93°30'.

  5. On long-term evolution of seasonal precipitation in southwestern Europe

    Directory of Open Access Journals (Sweden)

    F. Valero

    1996-09-01

    Full Text Available Annual cycles in long time series of precipitation from sixteen southwest European observatories have been analysed using complex demodulation. The stations have been clustered into two distinct regions and a hybrid one. They are referred to as the southwestern Europe precipitation Atlantic regime (SEPAR and the southwestern Europe precipitation Mediterranean regime (SEPMER, with the hybrid regime referred to in terms of the mean amplitude ratios between semiannual and annual rainfall components. Some evidence of linking between seasonal cycle harmonic amplitudes and the zonal circulation has been found for SEPAR stations and a more obscured relationship for the SEPMER region. Within the SEPAR region the strength of the relationship is diminished towards the north. A trend analysis of the amplitudes against time since 1920 has also been carried out and the results reveal a divergent pattern in trends between annual and semiannual component amplitudes for the SEPAR region. In fact, both an increasing annual-amplitude trend and a decreasing semiannual-amplitude trend are observed, in each case statistically significant. The fact that the seasonal cycle variability of rainfall in southwestern Europe becomes more sensitive southwards to changes in atmospheric zonal circulation over the North Atlantic might, in our opinion, be related to the swing of the circumpolar vortex.

  6. Morphological pattern of endometrial biopsies in southwestern Nigeria

    African Journals Online (AJOL)

    Background: Endometrium remains the most sensitive indicator of ovarian function and endometrial biopsy is one of the diagnostic procedures in endometrial pathology. The current study was carried out to examine the morphological pattern of endometrial biopsies in Ibadan, South-western Nigeria and compare the results ...

  7. Les dykes basiques du massif ancien de l'Ourika (Atlas de Marrakech, Maroc): géochimie et significationThe basic dykes of the Ourika old massif (High Atlas of Marrakech): Geochemistry and significance

    Science.gov (United States)

    Barakat, Ahmed; Marignac, Christian; Bouabdelli, Mohamed

    The Precambrian massif of Ourika is crosscut by two systems of basic dykes, striking N40°E and N90-120°E. Using incompatible trace elements, the two systems form two distinct chemical groups, displaying a continental tholeiitic affinity. The composition variations between the two defined groups can be due to heterogeneities of mantle sources and to contamination, during the magma ascent, by the continental crust. The emplacement of these basic dykes, before the late-PIII formations, can be related to the Neoproterozoic distension generalised to the Anti-Atlas chain. To cite this article: A. Barakat et al., C. R. Geoscience 334 (2002) 827-833.

  8. Tectonic strain changes affecting the development of deep seated gravitational slope deformations in the Bohemian Massif and Outer Western Carpathians

    Czech Academy of Sciences Publication Activity Database

    Stemberk, Josef; Hartvich, Filip; Blahůt, Jan; Rybář, Jan; Krejčí, O.

    2017-01-01

    Roč. 289, SI (2017), s. 3-17 ISSN 0169-555X R&D Projects: GA MŠk(CZ) LG15007; GA MŠk(CZ) LM2015079 Institutional support: RVO:67985891 Keywords : Deep seated gravitational slope deformations * Displacement monitoring * Tectonic strain changes * Bohemian Massif * Outer Western Carpathians Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.958, year: 2016

  9. Insecticide resistance in Anopheles gambiae from south-western Chad, Central Africa

    Directory of Open Access Journals (Sweden)

    Etang Josiane

    2008-09-01

    Full Text Available Abstract Background Indoor residual spraying and insecticide-treated nets (ITN are essential components of malaria vector control in Africa. Pyrethroids are the only recommended compounds for nets treatment because they are fast-acting insecticides with low mammalian toxicity. However, there is growing concern that pyrethroid resistance may threaten the sustainability of ITN scaling-up programmes. Here, insecticide susceptibility was investigated in Anopheles gambiae sensu lato from an area of large scale ITN distribution programme in south-western Chad. Methods Susceptibility to 4% DDT, 0.05% deltamethrin, 0.75% permethrin, 0.1% bendiocarb and 5% malathion was assessed using the WHO standard procedures for adult mosquitoes. Tests were carried out with two to four days-old, non-engorged female mosquitoes. The An. gambiae Kisumu strain was used as a reference. Knockdown effect was recorded every 5 min and mortality scored 24 h after exposure. Mosquitoes were identified to species and molecular form by PCR-RFLP and genotypes at the kdr locus were determined in surviving specimens by Hot Oligonucleotide Ligation Assay (HOLA. Results During this survey, full susceptibility to malathion was recorded in all samples. Reduced susceptibility to bendiocarb (mortality rate of 96.1% was found in one sample out of nine assayed. Increased tolerance to pyrethroids was detected in most samples (8/9 with mortality rates ranging from 70.2 to 96.6% for deltamethrin and from 26.7 to 96.3% for permethrin. Pyrethroid tolerance was not associated with a significant increase of knock-down times. Anopheles arabiensis was the predominant species of the An. gambiae complex in the study area, representing 75 to 100% of the samples. Screening for kdr mutations detected the L1014F mutation in 88.6% (N = 35 of surviving An. gambiae sensu stricto S form mosquitoes. All surviving An. arabiensis (N = 49 and M form An. gambiae s.s. (N = 1 carried the susceptible allele

  10. Effects of interaction between ultramafic tectonite and mafic magma on Nd-Pb-Sr isotopic systems in the Neoproterozoic Chaya Massif, Baikal-Muya ophiolite belt

    Science.gov (United States)

    Amelin, Yuri V.; Ritsk, Eugeni Yu.; Neymark, Leonid A.

    1997-04-01

    Sm-Nd, Rb-Sr and U-Pb isotopic systems have been studied in minerals and whole rocks of harzburgites and mafic cumulates from the Chaya Massif, Baikal-Muya ophiolite belt, eastern Siberia, in order to determine the relationship between mantle ultramafic and crustal mafic sections. Geological relations in the Chaya Massif indicate that the mafic magmas were emplaced into, and interacted with older solid peridotite. Hand picked, acid-leached, primary rock-forming and accessory minerals (olivine, orthopyroxene, clinopyroxene and plagioclase) from the two harzburgite samples show coherent behavior and yield 147Sm/ 144Nd- 143Nd/ 144Nd and 238U/ 204Pb- 206Pb/ 204Pb mineral isochrons, corresponding to ages of 640 ± 58 Ma (95% confidence level) and 620 ± 71 Ma, respectively. These values are indistinguishable from the crystallization age of the Chaya mafic units of 627 ± 25 Ma (a weighted average of internal isochron Sm-Nd ages of four mafic cumulates). The Rb-Sr and Sm-Nd isotopic systems in the harzburgite whole-rock samples were disturbed by hydrothermal alteration. These alteration-related isotopic shifts mimic the trend of variations in primary isotopic compositions in the mafic sequence, thus emphasizing that isotopic data for ultramafic rocks should be interpreted with great caution. On the basis of initial Sr and Nd values, ultramafic and mafic rocks of the Chaya Massif can be divided into two groups: (1) harzburgites and the lower mafic unit gabbronorites withɛ Nd = +6.6 to +7.1 andɛ Sr = -11 to -16; and (2) websterite of the lower unit and gabbronorites of the upper mafic unit:ɛ Nd = +4.6 to +6.1 andɛ Sr = -8 to -9. Initial Pb isotopic ratios are identical in all rocks studied, with mean values of 206Pb/ 204Pb= 16.994 ± 0.023 and 207Pb/ 204Pb= 15.363 ± 0.015. The similarity of ages and initial isotopic ratios within the first group indicates that the isotopic systems in the pre-existing depleted peridotite were reset by extensive interaction with

  11. Pleistocene speleothem fracturing in the foreland of the Western Carpathians: a case study from the seismically active eastern margin of the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Bábek, O.; Briestenský, Miloš; Přecechtělová, G.; Štěpančíková, Petra; Hellstrom, J.C.; Drysdale, R.N.

    2015-01-01

    Roč. 59, č. 3 (2015), s. 491-506 ISSN 1641-7291 R&D Projects: GA ČR GAP210/12/0573 Institutional support: RVO:67985891 Keywords : speleothems * U/Th series dating * palaeoseismicity * Pleistocene * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.858, year: 2015

  12. Southwestern Institute of Physics annual report (2000)

    International Nuclear Information System (INIS)

    2001-01-01

    The research results and engineering progress of SWIP (Southwestern Institute of Physics) during the year of 2000 was summarized in this annual report. The contents divided into five parts: 1. tokamak experimental diagnoses and tokamak engineering; 2. fusion reactor and fusion reactor materials; 3. plasma theory and calculation; 4. technique development and application; 5. appendix 31 theses and presented in this report

  13. Three-dimensional velocity model of the crust of the Bohemian Massif and its effects on seismic tomography of the upper mantle

    Czech Academy of Sciences Publication Activity Database

    Karousová, Hana; Plomerová, Jaroslava; Babuška, Vladislav

    2012-01-01

    Roč. 56, č. 1 (2012), s. 249-267 ISSN 0039-3169 R&D Projects: GA ČR GA205/07/1088; GA AV ČR IAA300120709 Institutional research plan: CEZ:AV0Z30120515 Keywords : crustal structure * seismic methods * Bohemian Massif * teleseismic tomography Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.975, year: 2012

  14. Fire and birds in the southwestern United States

    Science.gov (United States)

    Carl E. Bock; William M. Block

    2005-01-01

    Fire is an important ecological force in many southwestern ecosystems, but frequencies, sizes, and intensities of fire have been altered historically by grazing, logging, exotic vegetation, and suppression. Prescribed burning should be applied widely, but under experimental conditions that facilitate studying its impacts on birds and other components of biodiversity....

  15. Cl-rich hydrous mafic mineral assemblages in the Highiș massif, Apuseni Mountains, Romania

    Science.gov (United States)

    Bonin, Bernard; Tatu, Mihai

    2016-08-01

    The Guadalupian (Mid-Permian) Highiș massif (Apuseni Mountains, Romania) displays a bimodal igneous suite of mafic (gabbro, diorite) and A-type felsic (alkali feldspar granite, albite granite, and hybrid granodiorite) rocks. Amphibole is widespread throughout the suite, and yields markedly high chlorine contents. Three groups are identified: Cl-rich potassic hastingsite (2.60-3.40 wt% Cl) within A-type felsic rocks and diorite, mildly Cl-rich pargasite to hornblende (0.80-1.90 wt% Cl) within gabbro, and low F-Cl hornblende within gabbro and hybrid granodiorite. Coexisting biotite is either Cl-rich within diorite, or F-Cl-poor to F-rich within A-type felsic rocks. Chlorine and fluorine are distributed in both mafic phases, according to the F-Fe and Cl-Mg avoidance rules. The low-Ti contents suggest subsolidus compositions. Cl-rich amphibole within diorite and A-type felsic rocks yields a restricted temperature range - from 575 °C down to 400 °C, whereas mildly Cl-rich amphibole within gabbro displays the highest range - from 675 to 360 °C. Temperatures recorded by Cl-rich biotite within diorite range from 590 to 410 °C. Biotite within A-type felsic rocks yields higher temperatures than amphibole: the highest values- from 640 to 540 °C - are recorded in low-F-Cl varieties, whereas the lowest values- from 535 to 500 °C - are displayed by F-rich varieties. All data point to halogen-rich hydrothermal fluids at upper greenschist facies conditions percolating through fractures and shear zones and pervasively permeating the whole Highiș massif, with F precipitating as interstitial fluorite and Cl incorporating into amphibole, during one, or possibly several, hydrothermal episodes that would have occurred during a ~ 150 My-long period of time extending from the Guadalupian (Mid-Permian) to the Albian (Mid-Cretaceous).

  16. Mineral compositions of plutonic rocks from the Lewis Hills massif, Bay of Islands ophiolite

    Science.gov (United States)

    Smith, Susan E.; Elthon, Don

    1988-01-01

    Mineral compositions of residual and cumulate rocks from the Lewis Hills massif of the Bay of Islands ophiolite complex are reported and interpreted in the context of magnetic processes involved in the geochemical evolution of spatially associated diabase dikes. The mineral compositions reflect greater degrees of partial melting than most abyssal peridotites do and appear to represent the most depleted end of abyssal peridotite compositions. Subsolidus equilibration between Cr-Al spinal and olivine generally has occurred at temperatures of 700 to 900 C. The spinel variations agree with the overall fractionation of basaltic magmas producing spinels with progressively lower Cr numbers. The compositions of clinopyroxenes suggest that the fractionation of two different magma series produced the various cumulate rocks.

  17. Strategic nutrient management of field pea in southwestern Uganda ...

    African Journals Online (AJOL)

    Strategic nutrient management of field pea in southwestern Uganda. ... African Journal of Food, Agriculture, Nutrition and Development ... Strategic nutrient management requires that the most limiting nutrient is known in order to provide a foundation for designing effective and sustainable soil fertility management ...

  18. Geomorphological response of a landscape to long-term tectonic and glacial processes: the upper Rhône basin, Central Swiss Alps

    Science.gov (United States)

    Stutenbecker, Laura; Schlunegger, Fritz

    2015-04-01

    The Rhône River in the Central Swiss Alps drains a 5380 km2 large basin that shows a high spatial variability of bedrock lithology, exhumation rate, glacial conditioning and climate. All of these factors were recently discussed to control erosion rates in orogenic settings in general, and particularly in the Alps (e.g. Wittmann et al. 2007, Vernon et al. 2008, Norton et al. 2010a). Thanks to various and densely distributed data, the upper Rhône basin located between the Aar massif and Lake Geneva is a suitable natural laboratory to analyze the landscape's geomorphological state and controlling factors at a basin-scale. In this study, we extract geomorphological parameters along the channels of ca. 50 tributary basins of various sizes that contribute to the sediment budget of the Rhône River either through sediment supply by torrents or debris flows. Their catchments are located in either granitic basement rocks (External Massifs), oceanic meta-sedimentary and ophiolitic rocks (Penninic nappes) or fine-grained continental-margin sediments (Helvetic nappes). The analysis of longitudinal river profiles from DEMs and slope/area relationships show that all tributary rivers within the Rhône basin are in topographic transient state that is expressed by mainly convex or concave-convex channel shapes with several knickpoints of either tectonic-lithological or glacial origin. Furthermore, the frequency distribution of elevations (hypsometry) along the river channel allows identifying glacially inherited morphologies and the recent erosional front. The combination of those different geomorphological data yields to a categorization of the tributary rivers into three endmember groups: (1) streams with highly convex profiles, testifying to a strong glacial inheritance, (2) concave-convex channels with several knickzones and inherited morphologies of past glaciations, (3) predominantly concave, relatively steep rivers with minor knickpoints and inner gorges. Assuming that

  19. Statistical Analysis of Terrestrial Water Storage Change Over Southwestern United States

    Science.gov (United States)

    Eibedingil, I. G.; Mubako, S. T.; Hargrove, W. L.; Espino, A. C.

    2017-12-01

    A warming trend over recent decades has aggravated water resource challenges in the arid southwestern region of the United States (U.S.). An increase in temperature, coupled with decreasing snowpack and rainfall have impacted the region's cities, ecosystems, and agriculture. The region is the largest contributor of agricultural products to the U.S. market resulting from irrigation. Water use through irrigation is stressing already limited terrestrial water resources. Population growth in recent decades has also led to increased water demand. This study utilizes products of the Gravity Recovery and Climate Experiment (GRACE) twin satellites experiment in MATLAB and ArcGIS to examine terrestrial water storage changes in the southwestern region of the U.S., comprised of the eight states of Texas, California, Nevada, Utah, Arizona, Colorado, New Mexico, and Oklahoma. Linear trend analysis was applied to the equivalent water-height data of terrestrial water storage changes (TWSC), precipitation, and air temperature. Correlation analysis was performed on couplings of TWSC - precipitation and TWSC - air temperature to examine the impact of temperature and precipitation on the region's water resources. Our preliminary results show a decreasing trend of TWSC from April 2002 to July 2016 in almost all parts of the region. Precipitation shows a decreasing trend from March 2000 to March 2017 for most of the region, except for sparse areas of increased precipitation near the northwestern coast of California, and a belt running from Oklahoma through the middle of Texas to the El Paso/New Mexico border. From April 2002 to December 2014, air temperature exhibited a negative trend for most of the region, except a larger part of California and a small location in central Texas. Correlation between TWSC and precipitation was mostly positive, but a negative trend was observed when TWSC and air temperature were correlated. The study contributes to the understanding of terrestrial water

  20. Re-Os and Lu-Hf isotopic constraints on the formation and age of mantle pyroxenites from the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Bizimis, M.; Haluzová, Eva; Sláma, Jiří; Svojtka, Martin; Hirajima, T.; Erban, V.

    256/257, July (2016), s. 197-210 ISSN 0024-4937 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100131203 Program:Program interní podpory projektů mezinárodní spolupráce AV ČR Institutional support: RVO:67985831 Keywords : Bohemian Massif * Lu-Hf * mantle * pyroxenite * Re-Os Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.677, year: 2016

  1. Types of soft-sediment deformation structures in a lacustrine Ploužnice member (Stephanian, Gzhelian, Pennsylvanian, Bohemian Massif), their timing, and possible trigger mechanism

    Czech Academy of Sciences Publication Activity Database

    Stárková, M.; Martínek, K.; Mikuláš, Radek; Rosenau, N.

    2015-01-01

    Roč. 104, č. 5 (2015), s. 1277-1298 ISSN 1437-3254 Institutional support: RVO:67985831 Keywords : soft-sediment deformation structures * bioturbation * early diagenetic carbonate * lacustrine facies * Bohemian Massif * Stephanian C * Krkonoše Piedmont Basin Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.133, year: 2015

  2. A middle Pleistocene through middle Miocene moraine sequence in the central Transantarctic Mountains, Antarctica

    Science.gov (United States)

    Balter, A.; Bromley, G. R.; Balco, G.; Thomas, H.; Jackson, M. S.

    2017-12-01

    Ice-free areas at high elevation in the central Transantarctic Mountains preserve extensive moraine sequences and drift deposits that comprise a geologic record of former East Antarctic Ice Sheet thickness and extent. We are applying cosmogenic-nuclide exposure dating to determine the ages of these moraine sequences at Roberts Massif and Otway Massif, at the heads of the Shackleton and Beardmore Glaciers, respectively. Moraines at these sites are for the most part openwork boulder belts characteristic of deposition by cold-based ice, which is consistent with present climate and glaciological conditions. To develop our chronology, we collected samples from 30 distinct ice-marginal landforms and have so far measured >100 3He, 10Be, and 21Ne exposure ages. Apparent exposure ages range from 1-14 Ma, which shows that these landforms record glacial events between the middle Pleistocene and middle Miocene. These data show that the thickness of the East Antarctic Ice Sheet in this region was similar to or thicker than present for long periods between the middle Miocene and today. The time range represented by these moraine sequences indicates that they may also provide direct geologic evidence for East Antarctic Ice Sheet behavior during past periods of warmer-than-present climate, specifically the Miocene and Pliocene. As the East Antarctic Ice Sheet is the largest ice sheet on earth, understanding its sensitivity to warm-climate conditions is critical for projections of ice sheet behavior and sea-level rise in future warm climates.

  3. Implementing northern goshawk habitat management in Southwestern forests: a template for restoring fire-adapted forest ecosystems.

    Science.gov (United States)

    James A. Youtz; Russell T. Graham; Richard T. Reynolds; Jerry. Simon

    2008-01-01

    Developing and displaying forest structural targets are crucial for sustaining the habitats of the northern goshawk, a sensitive species in Southwestern forests. These structural targets were described in Management Recommendations for the Northern Goshawk in the Southwestern United States (MRNG) (Reynolds, et al., 1992). The MRNG were developed in a unique food-web...

  4. Age and geochemistry of Neoproterozoic granitoids in the Songnen-Zhangguangcai Range Massif, NE China: Petrogenesis and tectonic implications

    Science.gov (United States)

    Luan, Jin-Peng; Xu, Wen-Liang; Wang, Feng; Wang, Zhi-Wei; Guo, Peng

    2017-10-01

    continental rifting. It is proposed that the microcontinental massifs within the eastern central Asian orogenic belt of NE China formed during or following the final stage of assembly of Rodinia before rifting away from the Tarim Craton in response to the Rodinia breakup.

  5. Gravimetric structure for the abyssal mantle massif of Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean, and its relation to active uplift

    Directory of Open Access Journals (Sweden)

    KENJI F. MOTOKI

    2014-06-01

    Full Text Available This paper presents gravimetric and morphologic analyses based on the satellite-derived data set of EGM2008 and TOPEX for the area of the oceanic mantle massif of the Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean. The free-air anomaly indicates that the present plate boundary is not situated along the longitudinal graben which cuts peridotite ridge, but about 20 km to the north of it. The high Bouguer anomaly of the peridotite ridge suggests that it is constituted mainly by unserpentinised ultramafic rocks. The absence of isostatic compensation and low-degree serpentinisation of the ultramafic rocks indicate that the peridotite ridge is sustained mainly by active tectonic uplift. The unparallel relation between the transform fault and the relative plate motion generates near north-south compression and the consequent tectonic uplift. In this sense, the peridotite massif is a pressure ridge due to the strike-slip displacement of the Saint Paul Transform Fault.

  6. K-Ar and Rb-Sr dating results of the Malyshevsky leucogranite massif (eastern slope of the Middle Urals)

    International Nuclear Information System (INIS)

    Smirnov, V.N.; Ivanov, K.S.; Ronkin, Yu.L.; Levin, V.Ya.; Bushlyakov, I.N.; Lepikhina, O.P.; Popova, O.Yu.

    2005-01-01

    The age of leucogranites and minerals forming the Malyshevsky massif was identified by the methods of K-Ar- and Rb-Sr dating for refining the sequence of magmatic complexes formation on the eastern slope of the Middle Urals. The obtained isotope age values, i.e. 229-277 mln. years (K-Ar) and 277.1±1.1 mln. years (Rb-Sr), permit considering the age of 277 mln. years as the period of the leucogranites formation and of the associated molybdenum mineralization [ru

  7. Estimation of surface runoff for calculating recharge in the karstic massif of Ports of Beseit (Tarragona, Spain) combining water balance in the soil and analysis of flow hydrographs

    International Nuclear Information System (INIS)

    Espinosa Martinez, S.; Custodio, E.

    2016-01-01

    For the right estimation of aquifer recharge by precipitation surface taking into account runoff is particularly relevant. Non considering it in the estimation of the groundwater resources can overestimate them. In the Baix Ebre aquifer system, in southern Catalonia, the surface and vadose zone runoff produced in the karstified carbonate formations in the Ports de Beseit massif has to be evaluated in order to achieve a better estimation of the resources transferred from this massif to the Plana de La Galera plain. Starting from the conceptual hydrogeological model, the average annual runoff is estimated. It includes the discharge from temporal perched aquifers in the Ports de Beseit massif, in the Matarraña river basin, and in the SE watershed to the Plana de La Galera plain. This is performed by analyzing the river and tributaries hydrographs, the filling and emptying hydrographs of the Ulldecona reservoir, and the soil water balance using the Visual Balan code applied to obtain the runoff in the Ulldecona reservoir watershed. The runoff has been estimated about 105±20 mm·yr−1, which represents 20–30% of average annual recharge in the Ports, estimated with soil water balance and atmospheric chloride deposition balance, about 350–500 mm·yr−1, which is mostly transferred laterally to the Plana de La Galera plain. (Author)

  8. Estimation of surface runoff for calculating recharge in the karstic massif of Ports of Beseit (Tarragona, Spain) combining water balance in the soil and analysis of flow hydrographs

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa Martinez, S.; Custodio, E.

    2016-07-01

    For the right estimation of aquifer recharge by precipitation surface taking into account runoff is particularly relevant. Non considering it in the estimation of the groundwater resources can overestimate them. In the Baix Ebre aquifer system, in southern Catalonia, the surface and vadose zone runoff produced in the karstified carbonate formations in the Ports de Beseit massif has to be evaluated in order to achieve a better estimation of the resources transferred from this massif to the Plana de La Galera plain. Starting from the conceptual hydrogeological model, the average annual runoff is estimated. It includes the discharge from temporal perched aquifers in the Ports de Beseit massif, in the Matarraña river basin, and in the SE watershed to the Plana de La Galera plain. This is performed by analyzing the river and tributaries hydrographs, the filling and emptying hydrographs of the Ulldecona reservoir, and the soil water balance using the Visual Balan code applied to obtain the runoff in the Ulldecona reservoir watershed. The runoff has been estimated about 105±20 mm·yr−1, which represents 20–30% of average annual recharge in the Ports, estimated with soil water balance and atmospheric chloride deposition balance, about 350–500 mm·yr−1, which is mostly transferred laterally to the Plana de La Galera plain. (Author)

  9. Volcanic and geochemical evolution of the Teno massif, Tenerife, Canary Islands: some repercussions of giant landslides on ocean island magmatism

    OpenAIRE

    Longpré, Marc-Antoine; Troll, Valentin R.; Walter, Thomas R.; Hansteen, Thor H.

    2009-01-01

    Large-scale, catastrophic mass wasting is a major process contributing to the dismantling of oceanic intraplate volcanoes. Recent studies, however, have highlighted a possible feedback relationship between flank collapse, or incipient instability, and subsequent episodes of structural rearrangement and/or renewed volcano growth. The Teno massif, located in northwestern Tenerife (Canary Islands), is a deeply eroded Miocene shield volcano that was built in four major eruptive phases punctuated ...

  10. Southwestern Institute of Physics annual report 2001

    International Nuclear Information System (INIS)

    2002-01-01

    In the year 2001, significant progresses in the engineering construction of the HL-2A tokamak were made at the Southwestern Institute of Physics (SWIP). At the same time, the research projects from Nuclear Energy Development Foundation, the National Defense Basic Research Foundation and the National Science Foundation of China were completely fulfilled. In addition 283 papers and reports were contributed, among them, 67 are included in the Annual Report

  11. Cancer distribution pattern in south-western Nigeria | Awodele ...

    African Journals Online (AJOL)

    The burden of cancer in Nigeria is appreciable with about 100,000 new cancer cases been reported in the country each year. This study aimed to determine the level of occurrence and pattern of distribution of different cancer types in two major functional cancer registries in south-western Nigeria. A desk review of the level ...

  12. Graptolite assemblages and stratigraphy of the lower Silurian Mrákotín Formation, Hlinsko Zone, NE interior of the Bohemian Massif (Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Štorch, Petr; Kraft, P.

    2009-01-01

    Roč. 84, č. 1 (2009), s. 51-74 ISSN 1214-1119 R&D Projects: GA AV ČR IAA3013405 Institutional research plan: CEZ:AV0Z30130516 Keywords : graptolites * stratigraphy * Llandovery * Hlinsko Zone * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.983, year: 2009

  13. A review of maternal mortality at Jimma Hospital, Southwestern ...

    African Journals Online (AJOL)

    A retrospective review of hospital maternal deaths at Jimma Hospital, Southwestern Ethiopia, covering the period from September 1990 to May 1999 was conducted with the objectives of determining the overall maternal mortality rate, observing trend of maternal mortality during the period, and identifying major causes of ...

  14. Pb-Pb age and Rb-Sr and Sm-Nd isotope signature of paleoproterozoic syenitic plutonism in the south of Salvador-Curaca mobile belt: Sao Felix Syenitic Massif, Bahia-Brazil

    International Nuclear Information System (INIS)

    Rosa, Maria de Lourdes da Silva; Conceicao, Herbet; Leal, Luiz Rogerio Bastos

    2001-01-01

    The Sao Felix Syenitic Massif (MSSF) has a tabular shape with about 32 km 2 that represents the south expression of the aligned syenitic plutonism, which occur in the middle part of Salvador-Curaca mobile belt (CMSC). Single zircon dating by stepwise Pb evaporation methodology yields an age of 2098 ± 1 Ma to SFSM. This data correlate the emplacement of the SFSM with the late stages of SCMB stabilization. This massif is isotopically characterized by negative epsilon neodymium values (-1.45 to -2.89) and low initial strontium ratio (0.701 to 0.704). SFSM isotopic signature is similar to the ones displayed by the others syenites from the belt and reflects an enriched source which should be related to a metasomatic enriched mantle. (author)

  15. Characterization of potassic materials of Pocos de Caldas alkaline massif, Southeastern Brazil

    International Nuclear Information System (INIS)

    Goncalves, P.; Navarro, F.C.; Roveri, C.D.; Bergerman, M.G.

    2016-01-01

    Potassium, which has featured in Brazil's agricultural sector and in the world's in the application of fertilizers, is present in magmatic rocks, such as nepheline syenite and phonolite, found in the Alkaline Massif of Pocos de Caldas (AMPC). The rare earth elements (REE), in turn, also occur in this region and have important uses in various industrial fields. The aim of this study was to investigate the potential of potassic rocks of AMPC in the fertilizer and rare earths industry. Five samples were collected and characterized. It was observed that there was no preferential concentration by granulometric range of potassium oxide, alumina, silica and iron oxide. Feldspathic mass, potash feldspar, and muscovite were found in all samples. The samples show REE with amounts greater than those found in the earth's crust, except for lutetium and scandium and possessed average content of potassium oxide from 8.70 to 14.40%. (author)

  16. Analysis of Culex and Aedes mosquitoes in southwestern Nigeria ...

    African Journals Online (AJOL)

    Introduction: Amplification and transmission of West Nile virus (WNV) by mosquitoes are driven by presence and number of viraemic/susceptible avian hosts. Methods: in order to predict risk of WNV infection to humans, we collected mosquitoes from horse stables in Lagos and Ibadan, southwestern Nigeria. The mosquitoes ...

  17. Deforestation Along the Maya Mountain Massif Belize-Guatemala Border

    Science.gov (United States)

    Chicas, S. D.; Omine, K.; Arevalo, B.; Ford, J. B.; Sugimura, K.

    2016-06-01

    In recent years trans-boundary incursions from Petén, Guatemala into Belize's Maya Mountain Massif (MMM) have increased. The incursions are rapidly degrading cultural and natural resources in Belize's protected areas. Given the local, regional and global importance of the MMM and the scarcity of deforestation data, our research team conducted a time series analysis 81 km by 12 km along the Belize-Guatemalan border adjacent to the protected areas of the MMM. Analysis drew on Landsat imagery from 1991 to 2014 to determine historic deforestation rates. The results indicate that the highest deforestation rates in the study area were -1.04% and -6.78% loss of forested area per year in 2012-2014 and 1995-1999 respectively. From 1991 to 2014, forested area decreased from 96.9 % to 85.72 % in Belize and 83.15 % to 31.52 % in Guatemala. During the study period, it was clear that deforestation rates fluctuated in Belize's MMM from one time-period to the next. This seems linked to either a decline in deforestation rates in Guatemala, the vertical expansion of deforestation in Guatemalan forested areas and monitoring. The results of this study urge action to reduce incursions and secure protected areas and remaining forest along the Belize-Guatemalan border.

  18. Simulating the productivity of desert woody shrubs in southwestern Texas

    Science.gov (United States)

    In the southwestern U.S., many rangelands have converted from native grasslands to woody shrublands dominated by creosotebush (Larrea tridentate) and honey mesquite (Prosopis glandulosa), threatening ecosystem health. Both creosotebush and mesquite have well-developed long root systems that allow t...

  19. Carbon and nitrogen cycling in southwestern ponderosa fine forests

    Science.gov (United States)

    Stephen C. Hart; Paul C. Selmants; Sarah I. Boyle; Steven T. Overby

    2007-01-01

    Ponderosa pine forests of the southwestern United States were historically characterized by relatively open, parklike stands with a bunchgrass-dominated understory. This forest structure was maintained by frequent, low-intensity surface fires. Heavy livestock grazing, fire suppression, and favorable weather conditions following Euro-American settlement in the late 19th...

  20. L'érosion dans les environnements glaciaires : exemple du Glacier des Bossons (Massif du Mont-Blanc, Haute-Savoie, France)

    OpenAIRE

    Godon , Cécile

    2013-01-01

    The study presented in this PhD memory aim at better define and quantify the present timeerosion processes in glacial and proglacial domain. The Glacier des Bossons, situated in theMont-Blanc massif (Haute-Savoie, France), is a good example of a natural and nonanthropizedsystem which allows us to study this topic. This glacier lies on two mainlithologies (the Mont-Blanc granite and the metamorphic bedrock) and this peculiarity is usedto determine the origin of the glacial sediments. The sedim...

  1. Quantifying the Eocene to Pleistocene topographic evolution of the southwestern Alps, France and Italy

    Science.gov (United States)

    Fauquette, Séverine; Bernet, Matthias; Suc, Jean-Pierre; Grosjean, Anne-Sabine; Guillot, Stéphane; van der Beek, Peter; Jourdan, Sébastien; Popescu, Speranta-Maria; Jiménez-Moreno, Gonzalo; Bertini, Adele; Pittet, Bernard; Tricart, Pierre; Dumont, Thierry; Schwartz, Stéphane; Zheng, Zhuo; Roche, Emile; Pavia, Giulio; Gardien, Véronique

    2015-02-01

    We evaluate the topographic evolution of the southwestern Alps using Eocene to Pleistocene pollen data combined with existing sedimentological, petrographic and detrital geo- and thermochronological data. We report 32 new pollen analyses from 10 sites completed by an existing dataset of 83 samples from 14 localities situated across the southwestern Alps, including both the pro- and the retro-foreland basins. The presence of microthermic tree pollen (mainly Abies, Picea) indicates that this part of the mountain belt attained elevations over 1900 m as early as the Oligocene. Inferred rapid surface uplift during the mid-Oligocene coincided with a previously documented brief phase of rapid erosional exhumation, when maximum erosion rates may have reached values of up to 1.5-2 km/Myr. Slower long-term average exhumation rates of ∼0.3 km/Myr since the Late Oligocene helped maintaining the high Alpine topography of the southwestern Alps until today. The relative abundances of meso-microthermic tree pollen (Cathaya, Cedrus and Tsuga) and microthermic tree pollen (Abies, Picea) in the pro- and retro-foreland basin deposits, indicate that the present-day asymmetric topography, with a relatively gentle western flank and steeper eastern flank, was established early in the southwestern Alps, at least since the Early Miocene, and possibly since the Oligocene or Late Eocene. Therefore, the high topography and asymmetric morphology of this part of the Alps has been maintained throughout the past ∼30 Ma.

  2. Phase equilibria modelling and zircon dating for Precambrian metapelites from Xinghuadukou Group in Lvlin Forest of Erguna Massif, NE China

    Science.gov (United States)

    Xu, Jiulei; Zheng, Changqing; Tajcmanova, Lucie; Zhong, Xin; Xu, Xuechun; Han, Xiaomeng; Wang, Zhaoyuan

    2017-04-01

    Xinghuadukou Group, the basement metamorphic complex of Erguna Massif in NE China, is considered to be Mesoproterozoic with Sm-Nd age of 1157±32 Ma. However, the new zircon data from these metamorphic supracrustal rocks in Lvlin Forest show that they formed in Neoproterozoic with the age of 800 Ma. Old zircon age with 2.5 Ga, 2.0 Ga and 1.8 Ga, indicate that the Erguna Massif had an affinity to both Columbia and Rodinia continents. Furthermore, we also present 500 Ma metamorphic age in micashists and 500 Ma age of adjacent granitoids that might have thermally influenced its surrounding. No detailed studies have been undertaken on the metamorphic evolution of the Xinghuadukou Complex. The typical paragneissic mineral assemblage of garnet sillimanite mica schist is Grt+Sil+Bt+Mus+Qtz±Kfs. (Zhou et al., 2011) proposed that the Xinghuadukou Complex appears to have undergone similar granulite facies metamorphic conditions based on the similarity of mineral assemblages to the Mashan Complex in the Jiamusi Massif, NE China. However, the new phase equilibria modelling result shows that these rocks are high amphibolite facies product with 650℃. We can easily find K-feldspar formed by partial melting due to the consuming of muscovite. Also the remaining muscovite is directly connected with a fluid channel in thin sections which indicate that the remaining muscovite formed from retrograde with the existence of fluid. The zoned garnet has low MgO and high CaO content in rims and high MgO and low CaO content in core. It seems that this garnet has high pressure and low temperature (HP-LT) in rims and low pressure and high temperature (LP-HT) in core which would point to an anti-clockwise metamorphic evolution. Zhou, J.B., Wilde, S.A., Zhang, X.Z., Zhao, G.C., Liu, F.L., Qiao, D.W., Ren, S.M. and Liu, J.H., 2011b. A> 1300km late Pan-African metamorphic belt in NE China: new evidence from the Xing'an block and its tectonic implications. Tectonophysics, 509(3): 280-292.

  3. L'Arenig Llanvirn du Haut Atlas occidental et central (Maroc). Environnements sédimentaires, paléogéographie et contrôle de la sédimentation

    Science.gov (United States)

    Chacrone, Choukri; Hamoumi, Naïma

    2005-09-01

    The sedimentological study of Arenig-Llanvirn successions of Aït Lahsen (western High Atlas), Tizi-n-Tichka and Imini (central High Atlas) allow us to recognise two independent epeiric seas. In the western High Atlas, the sedimentation occurred in a wave- and storm-influenced delta, alimented by a source situated at the present-day location of the Argana corridor, under the control of sea-level fluctuations and subsidence. In the central High Atlas, the sedimentation occurred in an influenced tide and episodic storm delta, alimented by sources situated at the present-day location of the Siroua and Ouzellagh Massifs under the control of sea-level fluctuations and tectonics. To cite this article: C. Chacrone, N. Hamoumi, C. R. Geoscience 337 (2005).

  4. Energy map of southwestern Wyoming, Part B: oil and gas, oil shale, uranium, and solar

    Science.gov (United States)

    Biewick, Laura R.H.; Wilson, Anna B.

    2014-01-01

    The U.S. Geological Survey (USGS) has compiled Part B of the Energy Map of Southwestern Wyoming for the Wyoming Landscape Conservation Initiative (WLCI). Part B consists of oil and gas, oil shale, uranium, and solar energy resource information in support of the WLCI. The WLCI represents the USGS partnership with other Department of the Interior Bureaus, State and local agencies, industry, academia, and private landowners, all of whom collaborate to maintain healthy landscapes, sustain wildlife, and preserve recreational and grazing uses while developing energy resources in southwestern Wyoming. This product is the second and final part of the Energy Map of Southwestern Wyoming series (also see USGS Data Series 683, http://pubs.usgs.gov/ds/683/), and encompasses all of Carbon, Lincoln, Sublette, Sweetwater, and Uinta Counties, as well as areas in Fremont County that are in the Great Divide and Green River Basins.

  5. Thermo chronology by fission tracks of the conjugated rift margins of the Liguro-Provencal basin: Corsica and the Maures-Tanneron Massif

    International Nuclear Information System (INIS)

    Jakni, B.

    2000-01-01

    We have employed apatite fission-track (AFT) thermo-chronology on granitic and metamorphic samples taken from Corsican and Maures-Tanneron basement rocks as well as alpine 'schistes lustres' units in Corsica, in order to constrain the cooling histories and the tectonic evolution of the Liguro-Provencal basin margins. The AFT data indicate that: -) the Tanneron massif (AFT ages 145- 150 My) appears to record the earliest cooling history, reflecting thermal relaxation related to opening of the Tethys; -) the Maures basement (AFT ages 20-25 My) clearly records a thermo- tectonic evolution associated with Liguro-Provencal rifting; -) the island of Corsica, which was the main focus of this work and which shows a complex geomorphology and a poly-phased tectonic evolution. shows a remarkable zoning in the distribution of AFT ages, reflecting the signature of at least two post-Oligocene thermal events. Those events are related to the opening of Liguro-Provencal basin (20-25 My) in the west, and exhumation of the Hercynian basement related to Tyrrhenian extension (12- 16 My) in the east. In the east-Tenda shear zone, which forms the contact between the alpine units and Hercynian basement in northern Corsica, our results indicate that the Tenda Massif was being exhumed from about 21 Ma onwards. (author)

  6. Stable isotope systematics in mesozoic granites of Central and Northern California and Southwestern Oregon

    Science.gov (United States)

    Masi, U.; O'Neil, J.R.; Kistler, R.W.

    1981-01-01

    18O, D, and H2O+ contents were measured for whole-rock specimens of granitoid rocks from 131 localitics in California and southwestern Oregon. With 41 new determinations in the Klamath Mountains and Sierra Nevada, initial strontium isotope ratios are known for 104 of these samples. Large variations in ??18O (5.5 to 12.4), ??D (-130 to -31), water contents (0.14 to 2.23 weight percent) and initial strontium isotope ratios (0.7028 to 0.7095) suggest a variety of source materials and identify rocks modified by secondary processes. Regular patterns of variation in each isotopic ratio exist over large geographical regions, but correlations between the ratios are generally absent except in restricted areas. For example, the regular decrease in ??D values from west to east in the Sierra Nevada batholith is not correlative with a quite complex pattern of ??18O values, implying that different processes were responsible for the isotopic variations in these two elements. In marked contrast to a good correlation between (87Sr/86Sr)o and ??18O observed in the Peninsular Ranges batholith to the south, such correlations are lacking except in a few areas. ??D values, on the other hand, correlate well with rock types, chemistry, and (87Sr/86Sr)o except in the Coast Ranges where few of the isotopic signatures are primary. The uniformly low ??D values of samples from the Mojave Desert indicate that meteoric water contributed much of the hydrogen to the rocks in that area. Even so, the ??18O values and 18O fractionations between quartz and feldspar are normal in these same rocks. This reconnaissance study has identified regularities in geochemical parameters over enormous geographical regions. These patterns are not well understood but merit more detailed examination because they contain information critical to our understanding of the development of granitoid batholiths. ?? 1981 Springer-Verlag.

  7. Composition of soil microbiome along elevation gradients in southwestern highlands of Saudi Arabia.

    Science.gov (United States)

    Yasir, Muhammad; Azhar, Esam I; Khan, Imran; Bibi, Fehmida; Baabdullah, Rnda; Al-Zahrani, Ibrahim A; Al-Ghamdi, Ahmed K

    2015-03-14

    Saudi Arabia is mostly barren except the southwestern highlands that are susceptible to environmental changes, a hotspot for biodiversity, but poorly studied for microbial diversity and composition. In this study, 454-pyrosequencing of 16S rRNA gene hypervariable region V6 was used to analyze soil bacterial community along elevation gradients of the southwestern highlands. In general, lower percentage of total soil organic matter (SOM) and nitrogen were detected in the analyzed soil samples. Total 33 different phyla were identified across the samples, including dominant phyla Proteobacteria, Actinobacteria and Acidobacteria. Representative OTUs were grouped into 329 and 508 different taxa at family and genus level taxonomic classification, respectively. The identified OTUs unique to each sample were very low irrespective of the altitude. Jackknifed principal coordinates analysis (PCoA) revealed, overall differences in the bacterial community were more related to the quantity of specific OTUs than to their diversity among the studied samples. Bacterial diversity and soil physicochemical properties did not show consistent changes along the elevation gradients. The large number of OTUs shared between the studied samples suggest the presence of a core soil bacterial community in the southwestern highlands of Saudi Arabia.

  8. Summer rainfall over the southwestern Tibetan Plateau controlled by deep convection over the Indian subcontinent

    Science.gov (United States)

    Dong, Wenhao; Lin, Yanluan; Wright, Jonathon S.; Ming, Yi; Xie, Yuanyu; Wang, Bin; Luo, Yong; Huang, Wenyu; Huang, Jianbin; Wang, Lei; Tian, Lide; Peng, Yiran; Xu, Fanghua

    2016-01-01

    Despite the importance of precipitation and moisture transport over the Tibetan Plateau for glacier mass balance, river runoff and local ecology, changes in these quantities remain highly uncertain and poorly understood. Here we use observational data and model simulations to explore the close relationship between summer rainfall variability over the southwestern Tibetan Plateau (SWTP) and that over central-eastern India (CEI), which exists despite the separation of these two regions by the Himalayas. We show that this relationship is maintained primarily by ‘up-and-over' moisture transport, in which hydrometeors and moisture are lifted by convective storms over CEI and the Himalayan foothills and then swept over the SWTP by the mid-tropospheric circulation, rather than by upslope flow over the Himalayas. Sensitivity simulations confirm the importance of up-and-over transport at event scales, and an objective storm classification indicates that this pathway accounts for approximately half of total summer rainfall over the SWTP. PMID:26948491

  9. Origin of eclogite and garnet pyroxenite from the Moldanubian Zone of the Bohemian Massif, Czech Republic and its implication to other mafic layers embedded in orogenic peridotites

    Czech Academy of Sciences Publication Activity Database

    Obata, M.; Hirajima, T.; Svojtka, Martin

    2006-01-01

    Roč. 88, 1-2 (2006), s. 321-340 ISSN 0930-0708 R&D Projects: GA AV ČR IAA3013006 Institutional research plan: CEZ:AV0Z30130516 Keywords : eclogite * pyroxenite * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.038, year: 2006

  10. Multiphase formation of the Obří důl polymetallic skarn deposit, West Sudetes, Bohemian Massif: geochemistry and Re–Os dating of sulfide mineralization

    Czech Academy of Sciences Publication Activity Database

    Veselovský, F.; Ackerman, Lukáš; Pašava, J.; Žák, Karel; Haluzová, Eva; Creaser, R. A.; Dobeš, P.; Erban, V.; Tásler, R.

    2018-01-01

    Roč. 53, č. 5 (2018), s. 665-682 ISSN 0026-4598 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : Bohemian Massif * polymetallic skarn deposit * West Sudetes * arsenopyrite * Re–Os geochronology Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 3.396, year: 2016

  11. 36 CFR 261.73 - Regulations applicable to Region 3, Southwestern Region, as defined in § 200.2. [Reserved

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Regulations applicable to Region 3, Southwestern Region, as defined in § 200.2. [Reserved] 261.73 Section 261.73 Parks, Forests... § 261.73 Regulations applicable to Region 3, Southwestern Region, as defined in § 200.2. [Reserved] ...

  12. Silvics and silviculture in the southwestern pinyon-juniper woodlands

    Science.gov (United States)

    Gerald J. Gottfried

    2004-01-01

    Southwestern pinyon-juniper and juniper woodlands cover large areas of the western United States. The woodlands have been viewed as places of beauty and sources of valuable resource products or as weed-dominated landscapes that hinder the production of forage for livestock. They are special places because of the emotions and controversies that encircle their management...

  13. Recent emissions research in southwestern shrub and grassland fuels

    Science.gov (United States)

    David R. Weise; Wayne Miller; David R. Cocker; Heejung Jung; Seyedehsan Hosseini; Marko Princevac; Robert J. Yokelson; Ian Burling; Sheryl Akagi; Shawn Urbanski; WeiMin Hao

    2015-01-01

    While it is currently challenging to use prescribed burning in chaparral and other southwestern shrub fuel types due to many constraints, any such activities require smoke management planning. Information on fuels and emissions from chaparral were limited and based on older sampling systems. The DoD SERDP program funded a project to measure fuels and smoke emissions in...

  14. Prevalence of Infertility in Women in a Southwestern Nigerian ...

    African Journals Online (AJOL)

    The prevalence and common causes of infertility in women aged between 15 and 55 years was assessed in four hospital centers in Osun State, located in the SouthWestern part of Nigeria. A survey of a consecutive sample of 200 cases of infertility were carried out in four hospital centers with a total of 50 cases of infertility ...

  15. Warm–dry collocation of recent drought in southwestern China tied to moisture transport and climate warming

    International Nuclear Information System (INIS)

    Dai Xin-Gang; Liu Ye; Wang Ping

    2015-01-01

    This study aims to investigate the recent drought in southwestern China and its association with environmental changes in moisture transport (MT) and atmospheric circulation. Climatic Research Unit grid data, in situ observations in China, and ERA-interim reanalysis are used to study the characteristics of the drought and the associated mechanism. Recent precipitation trends show a pattern of “Northern wetting and Southern drying”, similar to the anti-phase of the climate pattern prevailing during 1980–2000 in mainland China; southwestern China incurred a severe drought during 2009–2013. Wavelet analysis reveals that the drought coincides with a warm–dry phase of temperature and precipitation on a period of about 20 years and beyond 100 years, where contributions account for 43% and 57% of the deficiency of the precipitation, averaged for 2003–2012, respectively. A further investigation reveals that the drought results chiefly from the decline of the southwestern monsoon MT toward southwestern China, in addition to mid-latitude circulation changes, which leads to more blockings near the Ural Mountains and the Sea of Okhotsk in the rainy season and negative anomalies around Lake Baikal and northeast China in the dry season. These anomalies are likely to be correlated with global sea surface temperature changes and need to be studied further. (paper)

  16. Multi-year climate variability in the Southwestern United States within a context of a dynamically downscaled twentieth century reanalysis

    Science.gov (United States)

    Carrillo, Carlos M.; Castro, Christopher L.; Chang, Hsin-I.; Luong, Thang M.

    2017-12-01

    This investigation evaluates whether there is coherency in warm and cool season precipitation at the low-frequency scale that may be responsible for multi-year droughts in the US Southwest. This low-frequency climate variability at the decadal scale and longer is studied within the context of a twentieth-century reanalysis (20CR) and its dynamically-downscaled version (DD-20CR). A spectral domain matrix methods technique (Multiple-Taper-Method Singular Value Decomposition) is applied to these datasets to identify statistically significant spatiotemporal precipitation patterns for the cool (November-April) and warm (July-August) seasons. The low-frequency variability in the 20CR is evaluated by exploring global to continental-scale spatiotemporal variability in moisture flux convergence (MFC) to the occurrence of multiyear droughts and pluvials in Central America, as this region has a demonstrated anti-phase relationship in low-frequency climate variability with northern Mexico and the southwestern US By using the MFC in lieu of precipitation, this study reveals that the 20CR is able to resolve well the low-frequency, multiyear climate variability. In the context of the DD-20CR, multiyear droughts and pluvials in the southwestern US (in the early twentieth century) are significantly related to this low-frequency climate variability. The precipitation anomalies at these low-frequency timescales are in phase between the cool and warm seasons, consistent with the concept of dual-season drought as has been suggested in tree ring studies.

  17. Late Mesoproterozoic to Early Paleozoic history of metamorphic basement from the southeastern Chiapas Massif Complex, Mexico, and implications for the evolution of NW Gondwana

    Science.gov (United States)

    Weber, Bodo; González-Guzmán, Reneé; Manjarrez-Juárez, Román; Cisneros de León, Alejandro; Martens, Uwe; Solari, Luigi; Hecht, Lutz; Valencia, Victor

    2018-02-01

    In this paper, U-Pb zircon geochronology, Lu-Hf and Sm-Nd isotope systematics, geochemistry and geothermobarometry of metaigneous basement rocks exposed in the southeastern Chiapas Massif Complex are presented. Geologic mapping of the newly defined "El Triunfo Complex" located at the southeastern edge of the Chiapas Massif reveals (1) partial melting of a metamorphic basement mainly constituted by mafic metaigneous rocks (Candelaria unit), (2) an Ediacaran metasedimentary sequence (Jocote unit), and (3) occurrence of massif-type anorthosite. All these units are intruded by undeformed Ordovician plutonic rocks of the Motozintla suite. Pressure and temperature estimates using Ca-amphiboles, plagioclase and phengite revealed prograde metamorphism that reached peak conditions at 650 °C and 6 kbar, sufficient for partial melting under water saturated conditions. Relict rutile in titanite and clinopyroxene in amphibolite further indicate a previous metamorphic event at higher P-T conditions. U-Pb zircon ages from felsic orthogneiss boudins hosted in deformed amphibolite and migmatite yield crystallization ages of 1.0 Ga, indicating that dry granitic protoliths represent remnants of Rodinia-type basement. Additionally, a mid-Tonian ( 920 Ma) metamorphic overprint is suggested by recrystallized zircon from a banded gneiss. Zircon from folded amphibolite samples yield mainly Ordovician ages ranging from 457 to 444 Ma that are indistinguishable from the age of the undeformed Motozintla plutonic suite. Similar ages between igneous- and metamorphic- zircon suggest a coeval formation during a high-grade metamorphic event, in which textural discrepancies are explained in terms of differing zircon formation mechanisms such as sub-solidus recrystallization and precipitation from anatectic melts. In addition, some amphibolite samples contain inherited zircon yielding Stenian-Tonian ages around 1.0 Ga. Lu-Hf and Sm-Nd isotopes and geochemical data indicate that the protoliths of

  18. A distinctive new frog species (Anura, Mantellidae supports the biogeographic linkage of two montane rainforest massifs in northern Madagascar

    Directory of Open Access Journals (Sweden)

    Mark D. Scherz

    2018-03-01

    Full Text Available We describe a new species of the genus Gephyromantis, subgenus GephyromantisVatomantis (Mantellidae, Mantellinae, from moderately high elevation (1164–1394 m a.s.l. on the Marojejy, Sorata, and Andravory Massifs in northern Madagascar. The new species, Gephyromantis (Vatomantis lomorina sp. n. is highly distinct from all other species, and was immediately recognisable as an undescribed taxon upon its discovery. It is characterised by a granular, mottled black and green skin, reddish eyes, paired subgular vocal sacs of partly white colour, bulbous femoral glands present only in males and consisting of three large granules, white ventral spotting, and a unique, amplitude-modulated advertisement call consisting of a series of 24–29 rapid, quiet notes at a dominant frequency of 5124–5512 Hz. Genetically the species is also strongly distinct from its congeners, with uncorrected pairwise distances ≥10 % in a fragment of the mitochondrial 16S rRNA gene to all other nominal Gephyromantis species. A molecular phylogeny based on 16S sequences places it in a clade with species of the subgenera Laurentomantis and Vatomantis, and we assign it to the latter subgenus based on its morphological resemblance to members of Vatomantis. We discuss the biogeography of reptiles and amphibians across the massifs of northern Madagascar, the evidence for a strong link between Marojejy and Sorata, and the role of elevation in determining community sharing across this landscape.

  19. Late Carboniferous remagnetisation of Palaeozoic rocks in the NE Rhenish Massif, Germany

    Science.gov (United States)

    Zwing, A.; Bachtadse, V.; Soffel, H. C.

    During stepwise thermal and alternating field demagnetisation experiments on Devonian and Lower Carboniferous carbonate and clastic rocks from the north-eastern part of the Rhenish Massif, Germany, three components of magnetisation (A, B, C) are identified. Component A is a recent viscous overprint that parallels the local present day geomagnetic field. Component B is mainly observed from 260 up to 550 °C during thermal demagnetisation and is carried by magnetite. In two localities, where red siltstones and red carbonate rocks were sampled, component B is stable up to 670 °C, indicating the presence of hematite. Three clusters of in situ B directions can be identified, which are controlled by the tectonic position of the sampling areas. These are from NW to SE: the Remscheid anticline (RA), the Lüdenscheid syncline (LS) and the Attendorn and Wittgenstein synclines (AS/WS). Standard and inclination-only fold tests, using parametric resampling, yield optimal statistical parameters at increasing amounts of untilting ranging from 0% in the South up to 57% in the North of the NE Rhenish Massif. Despite the variations in optimal untilting, the resulting site mean directions of component B do not differ significantly in inclination. These results are interpreted to reflect the acquisition of magnetisation during progressive northward migration of the deformation front in Late Carboniferous times. The resulting palaeolatitudes (RA: 1°S +2°-3°; LS: 2°S +3°-2°; AS/WS: 1°S +3°-4°) are in good agreement with the predicted position of the sampling area in the Late Carboniferous, as derived from a published Apparent Polar Wander Path for Baltica and Laurentia. The unblocking temperature spectra and the synfolding nature of B yield strong evidence that chemical processes, possibly driven by fluid migration during orogenesis, caused this remagnetisation. A third component C was observed in zones of tight folding with steeply dipping to overturned bedding planes and is

  20. Les roches basiques et ultrabasiques des Lacs Robert et le Trias de Chamrousse (Massif de Belledonne) Etude petrologique et geologique

    NARCIS (Netherlands)

    Tex, den E.

    1950-01-01

    La région que j’ai étudiée et relevée est située dans les Alpes françaises, à environ 4° longitude est et 50°15’ latitude nord, et à environ 2000 mètres d’altitude. Elle fait partie de la chaîne dite „chaîne de Belledonne” qui s’étend des massifs de Beaufort et du Grand Mont dans le N N E jusqu’à

  1. Seasonal mixed layer heat balance of the southwestern tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Foltz, G.R.; Vialard, J.; PraveenKumar, B.; McPhaden, M.J.

    from a long-term moored buoy are used in conjunction with satellite, in situ, and atmospheric reanalysis datasets to analyze the seasonal mixed layer heat balance in the thermocline ridge region of the southwestern tropical Indian Ocean. This region...

  2. DEFORESTATION ALONG THE MAYA MOUNTAIN MASSIF BELIZE-GUATEMALA BORDER

    Directory of Open Access Journals (Sweden)

    S. D. Chicas

    2016-06-01

    Full Text Available In recent years trans-boundary incursions from Petén, Guatemala into Belize’s Maya Mountain Massif (MMM have increased. The incursions are rapidly degrading cultural and natural resources in Belize’s protected areas. Given the local, regional and global importance of the MMM and the scarcity of deforestation data, our research team conducted a time series analysis 81 km by 12 km along the Belize-Guatemalan border adjacent to the protected areas of the MMM. Analysis drew on Landsat imagery from 1991 to 2014 to determine historic deforestation rates. The results indicate that the highest deforestation rates in the study area were −1.04% and −6.78% loss of forested area per year in 2012-2014 and 1995-1999 respectively. From 1991 to 2014, forested area decreased from 96.9 % to 85.72 % in Belize and 83.15 % to 31.52 % in Guatemala. During the study period, it was clear that deforestation rates fluctuated in Belize's MMM from one time-period to the next. This seems linked to either a decline in deforestation rates in Guatemala, the vertical expansion of deforestation in Guatemalan forested areas and monitoring. The results of this study urge action to reduce incursions and secure protected areas and remaining forest along the Belize-Guatemalan border.

  3. Length-weight relationships for fishes off the southwestern coast of ...

    African Journals Online (AJOL)

    Length-weight relationships are presented for 24 fish species representing 12 families captured monthly from February 2009 to March 2010, off the southwestern coast of Taiwan. 12 of these species are documented in fishbase, but no length-weight relationships were available. One record of maximum length was recorded.

  4. Consumption of seeds of southwestern white pine (Pinus strobiformis) by Black Bear (Ursus americanus)

    Science.gov (United States)

    Mattson, David J.; Arundel, Terry A.

    2013-01-01

    We report a discovery of black bears (Ursus americanus) consuming seeds of southwestern white pine (Pinus strobiformis) on north slopes of the San Francisco Peaks near Flagstaff, Arizona, in high-elevation, mixed-species conifer forest. In one instance, a bear had obtained seeds from cones excavated from a larder horde made by a red squirrel (Tamiasciurus hudsonicus). Consumption of seeds of southwestern white pine by bears had not been previously documented. This discovery adds to the number of species of pine used by bears for food as well as the geographic range within which the behavior occurs.

  5. The Forest Service, Rocky Mountain Research Station's Southwestern Borderlands Ecosystem Management Project: building on ten years of success [Abstract

    Science.gov (United States)

    Gerald J. Gottfried; Carleton B. Edminster

    2005-01-01

    The USDA Forest Service initiated the Southwestern Borderlands Ecosystem Management Project in 1994. The Project concentrates on the unique, relatively unfragmented landscape of exceptional biological diversity in southeastern Arizona and southwestern New Mexico. Its mission is to: "Contribute to the scientific basis for developing and implementing a comprehensive...

  6. What drives low-severity fire in the southwestern USA?

    Science.gov (United States)

    Sean A. Parks; Solomon Z. Dobrowski; Matthew H. Panunto

    2018-01-01

    Many dry conifer forests in the southwestern USA and elsewhere historically (prior to the late 1800’s) experienced fairly frequent surface fire at intervals ranging from roughly five to 30 years. Due to more than 100 years of successful fire exclusion, however, many of these forests are now denser and more homogenous, and therefore they have a greater probability of...

  7. Fragmentation patterns of evergreen oak woodlands in Southwestern Iberia

    DEFF Research Database (Denmark)

    Costa, A.; Madeira, M.; Lima Santos, J.

    2014-01-01

    Mediterranean evergreen oak woodlands (composed of Quercus suber L. and Quercus rotundifolia Lam.) are becoming increasingly fragmented in the human-modified landscapes of Southwestern Portugal and Spain. Previous studies have largely neglected to assess the spatial changes of oak woodlands...... patterns of oak recruitment and therefore, its study may be helpful in highlighting future baselines for the sustainable management of oak woodlands....

  8. Estimation of the lion ( Panthera leo ) population in the southwestern ...

    African Journals Online (AJOL)

    A previous estimate of the lion (Panthera leo) population in the southwestern Kgalagadi Transfrontier Park (KTP) was made over 20 years ago. This together with increased fears regarding the viability of the population as a result of recent killings of roaming animals, an observed increase in non-violent mortalities during ...

  9. Medical ethnobotany of herbal practitioners in the Turkestan Range, southwestern Kyrgyzstan

    Directory of Open Access Journals (Sweden)

    Lukas Pawera

    2016-03-01

    Full Text Available This study recorded and analyzed traditional knowledge of medicinal plants in the Turkestan Range in southwestern Kyrgyzstan, where ethnobotanical knowledge has been largely under-documented to date. Data was collected through participant observation and both semi-structured and in-depth interviews with 10 herbal specialists. A total of 50 medicinal plant taxa were documented, distributed among 46 genera and 27 botanical families. In folk medicine they are applied in 75 different formulations, which cure 63 human and three animal ailments. Quantitative ethnobotanical indices were calculated to analyze traditional knowledge of the informants and to determine the cultural importance of particular medicinal plants. Ziziphora pamiroalaica, Peganum harmala, and Inula orientalis obtained the highest use value (UV. The best-represented and culturally important families were Lamiaceae, Asteraceae, and Apiaceae. Gastro-intestinal system disorders was the most prevalent ailment category. Most medicinal plants were gathered from nearby environments, however, species with a higher cultural value occurred at distant rather than nearby collection sites. The findings of this study proved the gap in documentation of traditional knowledge in Kyrgyzstan, indicating that further studies on the traditional use of wild plant resources could bring important insights into ecosystems’ diversity with implications to human ecology and bio-cultural diversity conservation in Central Asia.

  10. Application of GIS technologies to monitor secondary radioactive contamination in the Delegen mountain massif

    Science.gov (United States)

    Alipbeki, O.; Kabzhanova, G.; Kurmanova, G.; Alipbekova, Ch.

    2016-06-01

    The territory of the Degelen mountain massif is located within territory of the former Semipalatinsk nuclear test site and it is an area of ecological disaster. Currently there is a process of secondary radioactive contamination that is caused by geodynamic processes activated at the Degelen array, violation of underground hydrological cycles and as a consequence, water seepage into the tunnels. One of the methods of monitoring of geodynamic processes is the modern technology of geographic information systems (GIS), methods of satellite radar interferometry and high accuracy satellite navigation system in conjunction with radioecological methods. This paper discusses on the creation of a GIS-project for the Degelen array, facilitated by quality geospatial analysis of the situation and simulation of the phenomena, in order to maximize an objective assessment of the radiation situation in this protected area.

  11. A Natural History Summary and Survey Protocol for the Southwestern Willow Flycatcher

    Science.gov (United States)

    Sogge, Mark K.; ,; Ahlers, Darrell; ,; Sferra, Susan J.; ,

    2010-01-01

    The Southwestern Willow Flycatcher (Empidonax traillii extimus) has been the subject of substantial research, monitoring, and management activity since it was listed as an endangered species in 1995. When proposed for listing in 1993, relatively little was known about the flycatcher's natural history, and there were only 30 known breeding sites supporting an estimated 111 territories rangewide (Sogge and others, 2003a). Since that time, thousands of presence/absences surveys have been conducted throughout the historical range of the flycatcher, and many studies of its natural history and ecology have been completed. As a result, the ecology of the flycatcher is much better understood than it was just over a decade ago. In addition, we have learned that the current status of the flycatcher is better than originally thought: as of 2007, the population was estimated at approximately 1,300 territories distributed among approximately 280 breeding sites (Durst and others, 2008a). Concern about the Southwestern Willow Flycatcher on a rangewide scale was brought to focus by Unitt (1987), who described declines in flycatcher abundance and distribution throughout the Southwest. E. t. extimus populations declined during the 20th century, primarily because of habitat loss and modification from activities, such as dam construction and operation, groundwater pumping, water diversions, and flood control. In 1991, the U.S. Fish and Wildlife Service (USFWS) designated the Southwestern Willow Flycatcher as a candidate category 1 species (U.S. Fish and Wildlife Service, 1991). In July 1993, the USFWS proposed to list E. t. extimus as an endangered species and to designate critical habitat under the Act (U.S. Fish and Wildlife Service, 1993). A final rule listing E. t. extimus as endangered was published in February 1995 (U.S. Fish and Wildlife Service, 1995); critical habitat was designated in 1997 (U.S. Fish and Wildlife Service, 1997). The USFWS Service released a Recovery Plan for

  12. Metamorphic history of garnet-rich gneiss at Ktiš in the Lhenice shear zone, Moldanubian Zone of the southern Bohemian Massif, inferred from inclusions and compositional zoning of garnet

    Czech Academy of Sciences Publication Activity Database

    Kobayashi, T.; Hirajima, T.; Kawakami, T.; Svojtka, Martin

    2011-01-01

    Roč. 124, 1/2 (2011), s. 46-65 ISSN 0024-4937 Institutional research plan: CEZ:AV0Z30130516 Keywords : Bohemian Massif * Lhenice shear zone * garnet * P-T path * partial melting Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.246, year: 2011

  13. Silviculture of southwestern ponderosa pine: The status of our knowledge

    Science.gov (United States)

    Gilbert H. Schubert

    1974-01-01

    Describes the status of our knowledge of ponderosa pine silviculture in the southwestern States of Arizona, Colorado, New Mexico, and Utah. Economic value, impact on other uses, and the timber resource are discussed first, followed by ecological background, site quality, growth and yield, and silviculture and management. Relevant literature is discussed along with...

  14. HIV/AIDS: Knowledge and attitudes of dentists in South-Western ...

    African Journals Online (AJOL)

    Objective: The purpose of this study was to assess the knowledge and attitudes of dentists in South-Western Nigeria in relation to HIV/AIDS. Materials and methods: A questionnaire survey of 164 dentists in Lagos, Ibadan and Benin The data was analyzed using Epi-info statistical software. Results: The modes of ...

  15. [Spatial and temporal clustering characteristics of typhoid and paratyphoid fever and its change pattern in 3 provinces in southwestern China, 2001-2012].

    Science.gov (United States)

    Wang, L X; Yang, B; Yan, M Y; Tang, Y Q; Liu, Z C; Wang, R Q; Li, S; Ma, L; Kan, B

    2017-11-10

    Objective: To analyze the spatial and temporal clustering characteristics of typhoid and paratyphoid fever and its change pattern in Yunnan, Guizhou and Guangxi provinces in southwestern China in recent years. Methods: The incidence data of typhoid and paratyphoid fever cases at county level in 3 provinces during 2001-2012 were collected from China Information System for Diseases Control and Prevention and analyzed by the methods of descriptive epidemiology and geographic informatics. And the map showing the spatial and temporal clustering characters of typhoid and paratyphoid fever cases in three provinces was drawn. SaTScan statistics was used to identify the typhoid and paratyphoid fever clustering areas of three provinces in each year from 2001 to 2012. Results: During the study period, the reported cases of typhoid and paratyphoid fever declined with year. The reported incidence decreased from 30.15 per 100 000 in 2001 to 10.83 per 100 000 in 2006(annual incidence 21.12 per 100 000); while during 2007-2012, the incidence became stable, ranging from 4.75 per 100 000 to 6.83 per 100 000 (annual incidence 5.73 per 100 000). The seasonal variation of the incidence was consistent in three provinces, with majority of cases occurred in summer and autumn. The spatial and temporal clustering of typhoid and paratyphoid fever was demonstrated by the incidence map. Most high-incidence counties were located in a zonal area extending from Yuxi of Yunnan to Guiyang of Guizhou, but were concentrated in Guilin in Guangxi. Temporal and spatial scan statistics identified the positional shifting of class Ⅰ clustering area from Guizhou to Yunnan. Class Ⅰ clustering area was located around the central and western areas (Zunyi and Anshun) of Guizhou during 2001-2003, and moved to the central area of Yunnan during 2004-2012. Conclusion: Spatial and temporal clustering of typhoid and paratyphoid fever existed in the endemic areas of southwestern China, and the clustering area

  16. Large teleseismic P-wave residuals observed at the Alban Hills volcano, Central Italy

    Directory of Open Access Journals (Sweden)

    H. Mahadeva Iyer

    1994-06-01

    Full Text Available We collected teleseismic waveforms from a digital microseismic network deployed by the Istituto Nazionale di Geofisica (ING in collaboration with the U.S. Geological Survey (USGS, on the Alban Hills Quaternary volcano during the 1989-1990 seismic swann. About 50 events were recorded by the network, 30 of them by at least 4 stations. We analysed the data in order to image crustal heterogeneities beneath the volcano. The results show large delay time residuals up to - 1 second for stations located on the volcano with respect to station CP9 of the National Seismic Network located about 20 km to the east, on the Apennines. This suggests that the whole area overlies a broad low-velocity region. Although the ray coverage is not very dense, we model the gross seismic structure beneath the volcano by inverting the teleseismic relative residuals with the ACH technique. The main features detected by tbc inversion are a low-velocity zone beneath the southwestern fiank of tbc volcano, and a high-velocity region beneath the center. The depth extension of these anomalous zones ranges between 5 and 16 km. The correspondence between the low-velocity region and the most recent activity of the volcano (- 0.027 Ma leads us to infer the presence of a still hot magmatic body in the crust beneath the southwestern side of the volcano, whereas the central part overlies the older and colder high-velocity volcanic roots related to the previous central activity (0.7 to 0.3 Ma.

  17. Ultramafites in the Gogolow-Jordanow massif and their predicted raw material evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Ciemniewska, M.; Czemier-Kowalska, M.; Lindner, M.; Salacinski, R.

    1981-01-01

    Based on mineralogical-petrographic analysis, it was established that the primary rocks of ultramafites were dunites and verlites which were exposed to intensive serpentinization, talcing, amphibolization, chloritization and carbonization. The constant components of rocks are ore minerals of paragenesis: chromite-ferrospinel-magnetite. Geochemical studies indicated the content (g/T): Cr 100-4800, Ni 100-3500, Co 30-160, Cu 1-100, while the computed values of the correlation coefficient revealed the existence of a link between Cr Ni, Co and Cr, Co and Ni. The mineralogical-petrographic composition, as well as the geological position of the studied massif indicate its affiliation to the ultramafites of the Alpine type and formation at the early stage of development of the geosyncline in the boundary zone between the consolidated gneiss block of the Archean and the mobile zone in relation to the deep faults. Although industrial concentrations of the expected were not found, the conducted observations make it possible to approach development of new prospecting concepts. Manifestation of the chromite mineralization and the ore accumulation in the region should be considered hydrothermal-metasomatic.

  18. Geochemistry of Spodosols formed in holocene till, Norra Storfjaellet Massif, northern Sweden

    International Nuclear Information System (INIS)

    Earl-goulet, J.R.; Mahaney, W.C.; Milner, M.W.; Hancock, R.G.V.

    1997-01-01

    Silt and clay size fractions of soils, from a transect of six Spodosols formed in the Norra Storfjaellet Massif, were analyzed by neutron activation to determine the degree to which pedogenic processes have influenced the distribution of macro, micro and trace elements. The distributions of Mg, Ca and Fe, together with Co, Cr and other trace elements in the profiles, suggest the presence of different parent materials, with A and E horizons arising from an influx of aeolian sediment. Translocation processes, both physical and chemical, occurred in the soil concentrating Fe and Br in the spodic(Bs) horizons of the profiles. The rare earth elements (REEs) are predominantly associated with the heavy mineral fraction of the soil material. The distributions of chondrite normalized REEs patterns of the profiles indicate that light rare earth element (LREE) concentrations increase with horizon depth. The depletion of LREEs in the upper soil horizons confirms the presence of material that is chemically different from that in the lower horizons, thus indicating a distinct chemical difference from the local glacial deposits. (author)

  19. Bedrock geologic map of the northern Alaska Peninsula area, southwestern Alaska

    Science.gov (United States)

    Wilson, Frederic H.; Blodgett, Robert B.; Blome, Charles D.; Mohadjer, Solmaz; Preller, Cindi C.; Klimasauskas, Edward P.; Gamble, Bruce M.; Coonrad, Warren L.

    2017-03-03

    The northern Alaska Peninsula is a region of transition from the classic magmatic arc geology of the Alaska Peninsula to a Proterozoic and early Paleozoic carbonate platform and then to the poorly understood, tectonically complex sedimentary basins of southwestern Alaska. Physiographically, the region ranges from the high glaciated mountains of the Alaska-Aleutian Range to the coastal lowlands of Cook Inlet on the east and Bristol Bay on the southwest. The lower Ahklun Mountains and finger lakes on the west side of the map area show strong effects from glaciation. Structurally, a number of major faults cut the map area. Most important of these are the Bruin Bay Fault that parallels the coast of Cook Inlet, the Lake Clark Fault that cuts diagonally northeast to southwest across the eastern part of the map area, and the presently active Holitna Fault to the northwest that cuts surficial deposits.Distinctive rock packages assigned to three provinces are overlain by younger sedimentary rocks and intruded by widely dispersed latest Cretaceous and (or) early Tertiary granitic rocks. Much of the east half of the map area lies in the Alaska-Aleutian Range province; the Jurassic to Tertiary Alaska-Aleutian Range batholith and derivative Jurassic sedimentary rocks form the core of this province, which is intruded and overlain by the Aleutian magmatic arc. The Lime Hills province, the carbonate platform, occurs in the north-central part of the map area. The Paleozoic and Mesozoic Ahklun Mountains province in the western part of the map area includes abundant chert, argillite, and graywacke and lesser limestone, basalt, and tectonic mélange. The Kuskokwim Group, an Upper Cretaceous turbidite sequence, is extensively exposed and bounds all three provinces in the west-central part of the map area.

  20. Tectono-metamorphic evolution of the Jomolhari massif: Variations in timing of syn-collisional metamorphism across western Bhutan

    Science.gov (United States)

    Regis, Daniele; Warren, Clare J.; Young, David; Roberts, Nick M. W.

    2014-03-01

    Our current understanding of the rates and timescales of mountain-building processes is largely based on information recorded in U-bearing accessory minerals such as monazite, which is found in low abundance but which hosts the majority of the trace element budget. Monazite petrochronology was used to investigate the timing of crustal melting in migmatitic metasedimentary rocks from the Jomolhari massif (NW Bhutan). The samples were metamorphosed at upper amphibolite to granulite facies conditions (~ 0.85 GPa, ~ 800 °C), after an earlier High-Pressure stage (P > 1.4 GPa), and underwent partial melting through dehydration melting reactions involving muscovite and biotite. In order to link the timing of monazite growth/dissolution to the pressure-temperature (P-T) evolution of the samples, we identified 'chemical fingerprints' in major and accessory phases that were used to back-trace specific metamorphic reactions. Variations in Eu anomaly and Ti in garnet were linked to the growth and dissolution of major phases (e.g. growth of K-feldspar and dehydration melting of muscovite/biotite). Differences in M/HREE and Y from garnet core to rim were instead related to apatite breakdown and monazite-forming reactions. Chemically zoned monazite crystals reacted multiple times during the metamorphic evolution suggesting that the Jomolhari massif experienced a prolonged high-temperature metamorphic evolution from 36 Ma to 18 Ma, significantly different from the P-T-time path recorded in other portions of the Greater Himalayan Sequence (GHS) in Bhutan. Our data demonstrate unequivocally that the GHS in Bhutan consists of units that experienced independent high-grade histories and that were juxtaposed across different tectonic structures during exhumation. The GHS may have been exhumed in response to (pulsed) mid-crustal flow but cannot be considered a coherent block.

  1. Endolithic microbial communities in carbonate precipitates from serpentinite-hosted hyperalkaline springs of the Voltri Massif (Ligurian Alps, Northern Italy).

    Science.gov (United States)

    Quéméneur, Marianne; Palvadeau, Alexandra; Postec, Anne; Monnin, Christophe; Chavagnac, Valérie; Ollivier, Bernard; Erauso, Gaël

    2015-09-01

    The Voltri Massif is an ophiolitic complex located in the Ligurian Alps close to the city of Genova (Northern Italy) where several springs discharge high pH (up to 11.7), low salinity waters produced by the active serpentinization of the ultramafic basement. Mixing of these hyperalkaline waters with the river waters along with the uptake of atmospheric carbon dioxide forms brownish carbonate precipitates covering the bedrock at the springs. Diverse archaeal and bacterial communities were detected in these carbonate precipitates using 454 pyrosequencing analyses of 16S ribosomal RNA (rRNA) genes. Archaeal communities were dominated by members of potential methane-producing and/or methane-oxidizing Methanobacteriales and Methanosarcinales (Euryarchaeota) together with ammonia-oxidizing Nitrososphaerales (Thaumarchaeota) similar to those found in other serpentinization-driven submarine and terrestrial ecosystems. Bacterial communities consisted of members of the Proteobacteria, Actinobacteria, Planctomycetes, Bacteroidetes, Chloroflexi, and Verrucomicrobia phyla, altogether accounting for 92.2% of total retrieved bacterial 16S rRNA gene sequences. Amongst Bacteria, potential chemolithotrophy was mainly associated with Alpha- and Betaproteobacteria classes, including nitrogen-fixing, methane-oxidizing or hydrogen-oxidizing representatives of the genera Azospirillum, Methylosinus, and Hydrogenophaga/'Serpentinomonas', respectively. Besides, potential chemoorganotrophy was attributed mainly to representatives of Actinobacteria and Planctomycetales phyla. The reported 16S rRNA gene data strongly suggested that hydrogen, methane, and nitrogen-based chemolithotrophy can sustain growth of the microbial communities inhabiting the carbonate precipitates in the hyperalkaline springs of the Voltri Massif, similarly to what was previously observed in other serpentinite-hosted ecosystems.

  2. BEHAVIOR AND PREY OF NESTING RED-SHOULDERED HAWKS IN SOUTHWESTERN OHIO

    Science.gov (United States)

    We used direct observations to quantify prey types, prey delivery rate, and adult and nestling behavior at nests of Red-shouldered Hawks (Buteo lineatus) in suburban southwestern Ohio. Twenty-one nests were observed for a total of 256 hr in 1997-2001. Small mammals made up the ...

  3. Magmatism and crustal extension: Constraining activation of the ductile shearing along the Gediz detachment, Menderes Massif (western Turkey)

    Science.gov (United States)

    Rossetti, Federico; Asti, Riccardo; Faccenna, Claudio; Gerdes, Axel; Lucci, Federico; Theye, Thomas

    2017-06-01

    The Menderes Massif of western Turkey is a key area to study feedback relationships between magma generation/emplacement and activation of extensional detachment tectonics. Here, we present new textural analysis and in situ U-(Th)-Pb titanite dating from selected samples collected in the transition from the undeformed to the mylonitized zones of the Salihli granodiorite at the footwall of the Neogene, ductile-to-brittle, top-to-the-NNE Gediz-Alaşheir (GDF) detachment fault. Ductile shearing was accompanied by the fluid-mediated sub-solidus transformation of the granodiorite to orthogneiss, which occurred at shallower crustal levels and temperatures compatible with the upper greenschist-to-amphibolite facies metamorphic conditions (530-580 °C and P system ages during fluid-assisted syn-tectonic re-crystallisation in the transition from magma crystallization and emplacement (at 16-17 Ma) to the syn-tectonic, solid-state shearing (at 14-15 Ma). A minimum time lapse of ca. 1-2 Ma is then inferred between the crustal emplacement of the Salihli granodiorite and nucleation of the ductile extensional shearing along the Gediz detachment. The reconstruction of the cooling history of the Salihli granodiorite documents a punctuated evolution dominated by two episodes of rapid cooling, between 14 Ma and 12 Ma ( 100 °C/Ma) and between 3 and 2 Ma ( 105 °C/Ma). We relate the first episode to nucleation and development of post-emplacement of ductile shearing along the GDF and the second to brittle high-angle faulting, respectively. Our dataset suggests that in the Menderes Massif the activation of ductile extension was a consequence, rather than the cause, of magma emplacement in the extending crust.

  4. Long-lasting Cadomian magmatic activity along an active northern Gondwana margin: U-Pb zircon and Sr-Nd isotopic evidence from the Brunovistulian Domain, eastern Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Soejono, I.; Janoušek, V.; Žáčková, E.; Sláma, Jiří; Konopásek, J.; Machek, Matěj; Hanžl, P.

    2017-01-01

    Roč. 106, č. 6 (2017), s. 2109-2129 ISSN 1437-3254 Institutional support: RVO:67985530 ; RVO:67985831 Keywords : Cadomian magmatic arc * Brunovistulian Domain * Bohemian Massif * Gondwana margin * U–Pb geochronology * geochemistry Subject RIV: DB - Geology ; Mineralogy; DC - Siesmology, Volcanology, Earth Structure (GFU-E) OBOR OECD: Geology; Volcanology (GFU-E) Impact factor: 2.283, year: 2016

  5. X-ray color maps of the zoned garnets from Silgará Formation metamorphic rocks,SantanderMassif, Eastern Cordillera (Colombia

    Directory of Open Access Journals (Sweden)

    Takasu Akira

    2010-12-01

    Full Text Available

    The metamorphic rocks of the Lower Paleozoic Silgará Formation of the Santander Massif, Eastern Cordillera (Colombia, were affected by a Barrovian-type metamorphism under low to high temperature and medium pressure conditions. These rocks contain garnet porphyroblasts, which show several kinds of chemical zoning patterns. The garnet grains behave as closed systems with respect to the rock matrix. Most of the observed zoning patterns are due to gradual changes in physicochemical conditions during growth. However, some garnet grains show complex zoning patterns during multiple deformation and metamorphic events.

  6. Interpretation of the chemical compositions of the cumulates of the gabro-anorthositic massif of Piau River - Bahia State

    International Nuclear Information System (INIS)

    Cruz, M.J.M.; Demange, M.; Fonteilles, M.

    1989-01-01

    The Rio Piau gabbroic and anorthositic complex is an Archean layered body; intrusive in the charnokitic and enderbitic terrains of the Jequie nucleous (Sao Francisco Craton, Bahia State, Brazil). The geochemical data of the Rio Piau massif consists of two magmatic series, better identified by REE, titanium, phosphorous, niobium and gallium contents. These two magmatic series show an evolution following the typical tholeiitic and several types of cumulatic rocks. The evolution of each magmatic series is made up by differentiation and accumulation, from basic terms (MgO = 10%) up to intermediate terms (MgO = 2%) and shows an evolution similar to the Skaergaard trends. (author) [pt

  7. Study on climate change in Southwestern China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zongxing

    2015-03-01

    Nominated by Chinese Academy of Sciences as an outstanding Ph.D. thesis. Offers a needed exploration of the temporal and spatial pattern of climate change in southwestern China. Explores the action mechanism among the large-scale atmospheric circulation system, the complicated topography, human activities and regional climate changes. Analyzes the response of glaciers to climate change from the aspects of morphology of the glacier, glacial mass balance and the process of hydrology. This thesis confirms many changes, including sharp temperature rise, interannual variability of precipitation, extreme climate events and significant decreases of sunshine duration and wind speed in southwestern China, and systemically explores the action mechanism between large-scale atmospheric circulation systems, the complicated topography, human activities and regional climate changes. This study also analyzes the response of glaciers to climate change so that on the one hand it clearly reflects the relationship between glacier morphologic changes and climate change; on the other, it reveals the mechanism of action of climate warming as a balance between energy and matter. The achievements of this study reflect a significant contribution to the body of research on the response of climate in cold regions, glaciers and human activities to a global change against the background of the typical monsoon climate, and have provided scientific basis for predictions, countermeasures against disasters from extreme weather, utilization of water and the establishment of counterplans to slow and adapt to climate change. Zongxing Li works at the Cold and Arid Region Environmental and Engineering Research Institute, Chinese Academy of Sciences, China.

  8. Study on climate change in Southwestern China

    International Nuclear Information System (INIS)

    Li, Zongxing

    2015-01-01

    Nominated by Chinese Academy of Sciences as an outstanding Ph.D. thesis. Offers a needed exploration of the temporal and spatial pattern of climate change in southwestern China. Explores the action mechanism among the large-scale atmospheric circulation system, the complicated topography, human activities and regional climate changes. Analyzes the response of glaciers to climate change from the aspects of morphology of the glacier, glacial mass balance and the process of hydrology. This thesis confirms many changes, including sharp temperature rise, interannual variability of precipitation, extreme climate events and significant decreases of sunshine duration and wind speed in southwestern China, and systemically explores the action mechanism between large-scale atmospheric circulation systems, the complicated topography, human activities and regional climate changes. This study also analyzes the response of glaciers to climate change so that on the one hand it clearly reflects the relationship between glacier morphologic changes and climate change; on the other, it reveals the mechanism of action of climate warming as a balance between energy and matter. The achievements of this study reflect a significant contribution to the body of research on the response of climate in cold regions, glaciers and human activities to a global change against the background of the typical monsoon climate, and have provided scientific basis for predictions, countermeasures against disasters from extreme weather, utilization of water and the establishment of counterplans to slow and adapt to climate change. Zongxing Li works at the Cold and Arid Region Environmental and Engineering Research Institute, Chinese Academy of Sciences, China.

  9. Entomologic Inoculation Rates of Anopheles arabiensis in Southwestern Ethiopia

    OpenAIRE

    Ulesido, Fekadu Massebo; Balkew, Meshesha; Gebre-Michael, Teshome; Lindtjørn, Bernt

    2013-01-01

    We collected anophelines every second week for one year from randomly selected houses in southwestern Ethiopia by using Centers for Disease Control (CDC) light traps, pyrethrum spray catches, and artificial pit shelter constructions to detect circumsporozoite proteins and estimate entomologic inoculation rates (EIRs). Of 3,678 Anopheles arabiensis tested for circumsporozoite proteins, 11 were positive for Plasmodium falciparum and three for P. vivax. The estimated annual P. falciparum EIR of ...

  10. Fire effects on Gambel oak in southwestern ponderosa pine-oak forests

    Science.gov (United States)

    Scott R. Abella; Peter Z. Fulé

    2008-01-01

    Gambel oak (Quercus gambelii) is ecologically and aesthetically valuable in southwestern ponderosa pine (Pinus ponderosa) forests. Fire effects on Gambel oak are important because fire may be used in pine-oak forests to manage oak directly or to accomplish other management objectives. We used published literature to: (1) ascertain...

  11. Phytophthora Species in Rivers and Streams of the Southwestern United States.

    Science.gov (United States)

    Stamler, Rio A; Sanogo, Soumalia; Goldberg, Natalie P; Randall, Jennifer J

    2016-08-01

    Phytophthora species were isolated from rivers and streams in the southwestern United States by leaf baiting and identified by sequence analysis of internal transcribed spacer (ITS) ribosomal DNA (rDNA). The major waterways examined included the Rio Grande River, Gila River, Colorado River, and San Juan River. The most prevalent species identified in rivers and streams were Phytophthora lacustris and P. riparia, both members of Phytophthora ITS clade 6. P. gonapodyides, P. cinnamomi, and an uncharacterized Phytophthora species in clade 9 were also recovered. In addition, six isolates recovered from the Rio Grande River were shown to be hybrids of P. lacustris × P. riparia Pathogenicity assays using P. riparia and P. lacustris failed to produce any disease symptoms on commonly grown crops in the southwestern United States. Inoculation of Capsicum annuum with P. riparia was shown to inhibit disease symptom development when subsequently challenged with P. capsici, a pathogenic Phytophthora species. Many Phytophthora species are significant plant pathogens causing disease on a large variety of crops worldwide. Closer examinations of streams, rivers, and forest soils have also identified numerous Phytophthora species that do not appear to be phytopathogens and likely act as early saprophytes in aquatic and saturated environments. To date, the Phytophthora species composition in rivers and streams of the southwestern United States has not been evaluated. This article details a study to determine the identity and prevalence of Phytophthora species in rivers and streams located in New Mexico, Arizona, Colorado, Utah, and Texas. Isolated species were evaluated for pathogenicity on crop plants and for their potential to act as biological control agents. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  12. Multilocus genotyping of Giardia duodenalis in captive non-human primates in Sichuan and Guizhou provinces, Southwestern China.

    Directory of Open Access Journals (Sweden)

    Zhijun Zhong

    Full Text Available Giardia duodenalis is a common human and animal pathogen. It has been increasingly reported in wild and captive non-human primates (NHPs in recent years. However, multilocus genotyping information for G. duodenalis infecting NHPs in southwestern China is limited. In the present study, the prevalence and multilocus genotypes (MLGs of G. duodenalis in captive NHPs in southwestern China were determined. We examined 207 fecal samples from NHPs in Sichuan and Guizhou provinces, and 16 specimens were positive for G. duodenalis. The overall infection rate was 7.7%, and only assemblage B was identified. G. duodenalis was detect positive in northern white-cheeked gibbon (14/36, 38.9%, crab-eating macaque (1/60, 1.7% and rhesus macaques (1/101, 0.9%. Multilocus sequence typing based on beta-giardin (bg, triose phosphate isomerase (tpi and glutamate dehydrogenase (gdh revealed nine different assemblage B MLGs (five known genotypes and four novel genotypes. Based on a phylogenetic analysis, one potentially zoonotic genotype of MLG SW7 was identified in a northern white-cheeked gibbon. A high degree of genetic diversity within assemblage B was observed in captive northern white-cheeked gibbons in Southwestern China, including a potentially zoonotic genotype, MLG SW7. To the best of our knowledge, this is the first report using a MLGs approach to identify G. duodenalis in captive NHPs in Southwestern China.

  13. Philorhizus occitanus sp. n. from the South-Western Alps (Piedmont, Italy (Coleoptera: Carabidae, Dromiini

    Directory of Open Access Journals (Sweden)

    Gianni Allegro

    2015-12-01

    Full Text Available Philorhizus occitanus sp. n. from the South-Western Alps (Ellero Valley and Maira Valley is described. This new species is similar to P. crucifer and P. notatus as far as the external morphology is concerned, but it is distinguished by the color pattern and the shape of elytra, as well as by the features of the median lobe of aedeagus. P. liguricus, which is easily distinguished from P. occitanus sp. n. by the external morphology, was already recorded from the South-Western Alps and from the Ligurian Apennines. P. occitanus sp. n. is a likely close relative of P. notatus, although the affinities of this relict flightless new species remain uncertain.

  14. Groundwater vulnerability assessment using hydrogeologic and geoelectric layer susceptibility indexing at Igbara Oke, Southwestern Nigeria

    Science.gov (United States)

    Oni, T. E.; Omosuyi, G. O.; Akinlalu, A. A.

    2017-12-01

    Groundwater vulnerability assessment was carried out at Igbara Oke Southwestern Nigeria, with a view to classify the area into vulnerability zones, by applying the electrical resistivity method, using Schlumberger electrode arrays with maximum electrode separation (AB/2) of 65 m in (41) different locations for data acquisition. Geoelectric parameters (layer resistivity and thickness) were determined from the interpreted data. The study area comprises four geoelectric layers (topsoil, lateritic layer, weathered/fractured layer and fresh basement). The geoelectric parameters of the overlying layers across the area were used to assess the vulnerability of the underlying aquifers to near-surface contaminants with the aid of vulnerability maps generated. Three models were compared by maps using geo-electrically derived models; longitudinal conductance, GOD (groundwater occurrence, overlying lithology and depth to the aquifer) and GLSI (geoelectric layer susceptibility indexing). The total longitudinal conductance map shows the north central part of the study area as a weakly protected (0.1-0.19) area, while the northern and southern parts have poor protective capacity (septic tank, refuse dump should be cited far from groundwater development area.

  15. Status of grey seals along mainland Europe from the Southwestern Baltic to France

    Directory of Open Access Journals (Sweden)

    Tero Härkönen

    2007-01-01

    Full Text Available The grey seal was a common species along mainland Europe during the Stone Age (8,000-5,500 BC. Along the North Sea coast populations started to decline substantially during the 11th century as a result of excessive hunting. The last breeding populations disappeared in the 16th century in the Wadden Sea, and before 1900 in the Kattegat-Skagerrak and the Southwestern Baltic as a result of an extermination campaign. No regular pupping occurred along mainland Europe until the end of the 1970s, when a breeding colony was established near Amrum in the German Wadden Sea. Somewhat later, additional breeding sites were discovered near Terschelling in the Dutch Wadden Sea (1980, at Helgoland, and off Brittany in France. Tracking of movements indicate these seal groups to be linked to the larger populations in the UK. Numbers of grey seals in the recolonised areas have increased over the years, but in the Kattegat-Skagerrak stable numbersof about 25 individuals have been observed since the 1970s, whereas more than 100 grey seals are found in the Southwestern Baltic. In the southeastern North Sea, 120 grey seals occur during moult at Helgoland, 120 in the German and over 1,130 in the Dutch parts of the Wadden Sea in 2004. Along the southern Dutch and Belgian coasts small groups are regularly observed, but no colonies have yet been established. In the colonies off Brittany in France about 105 grey seals have been counted. Successful pupping has only been recorded 3 times in the Kattegat-Skagerrak over the past 30 years, and 2-4 pups are born annually in France and the Southwestern Baltic. The relative strongholds for breeding along the European continent are the Dutch Wadden Sea, where in 2003/2004 at least 150 pups were recorded, Amrum in the German Wadden Sea (23 pups and Helgoland (8 pups. Consequently, total numbers of counted grey seals from the Southwestern Baltic to France amounted to at least 1,600 in 2004, while about 190 pups were born in the area.

  16. Fault slip versus slope deformations: Experience from paleoseismic trenches in the region with low slip-rate faults and strong Pleistocene periglacial mass wasting (Bohemian Massif)

    Czech Academy of Sciences Publication Activity Database

    Špaček, P.; Valenta, Jan; Tábořík, Petr; Ambrož, V.; Urban, M.; Štěpančíková, Petra

    2017-01-01

    Roč. 451, 7 SEP (2017), s. 56-73 ISSN 1040-6182 R&D Projects: GA ČR GAP210/12/0573; GA MŠk(CZ) LM2015079; GA MŠk 7AMB13AT023 Institutional support: RVO:67985891 Keywords : Active faulting * Paleoseismology * Slope deformation * Solifluction * Colluvium * Quaternary * Bohemian massif Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.199, year: 2016

  17. A plan for landscape fire restoration in the Southwestern Borderlands

    Science.gov (United States)

    Gerald J. Gottfried; Larry S. Allen

    2009-01-01

    Fires were prevalent in the Southwestern Borderlands of Arizona and New Mexico prior to the arrival of European-American settlers in the 1880s. The almost total exclusion of fires for more than 100 years has been linked to declines in biological diversity and a loss of productivity associated with the encroachment of woody vegetation into the grasslands and open...

  18. Hydrology of southwestern encinal oak ecosystems: A review and more

    Science.gov (United States)

    Gerald J. Gottfried; Peter F. Ffolliott; Daniel G. Neary

    2007-01-01

    Information about the hydrology of oak ecosystems of the southwestern United States and northern Mexico is lacking (Lopes and Ffolliott 1992, Baker et al. 1995) even though the woodlands and savannas cover more than 31,000 square miles. These ecosystems generally are found between 4,000 and 7,300 feet in elevation. Precipitation occurs in the winter and summer and...

  19. Haplosclerida (Porifera: Demospongiae) from the coast of Maranhao State, Brazil, Southwestern Atlantic.

    NARCIS (Netherlands)

    Campos, M.; Mothes, B.; Eckert, R.; van Soest, R.W.M.

    2005-01-01

    This work deals with haplosclerid sponges off the coast of Maranhão State, northeastern coast of Brazilian shelf (southwestern Atlantic). A new species is described, Haliclona (Halichoclona) lernerae. Four species are recorded for the first time for the Brazilian coast: Amphimedon caribica

  20. Weathering profiles in granitoid rocks of the Sila Massif uplands, Calabria, southern Italy: New insights into their formation processes and rates

    Science.gov (United States)

    Scarciglia, Fabio; Critelli, Salvatore; Borrelli, Luigi; Coniglio, Sabrina; Muto, Francesco; Perri, Francesco

    2016-05-01

    In this paper we characterized several weathering profiles developed on granitoid rocks in the Sila Massif upland (Calabria, southern Italy), integrating detailed macro- and micromorphological observations with physico-mechanical field tests and petrographic, mineralogical and geochemical analyses. We focused our attention on the main weathering and pedogenetic processes, trying to understand apparent discrepancies between weathering grade classes based on field description and geomechanical properties, and two common weathering indices, such as the micropetrographic index (Ip) and the chemical index of alteration (CIA). Our results showed that sericite on plagioclase and biotite chloritization, that represent inherited features formed during late-stage hydrothermal alteration of granitoid rocks, may cause an overestimation of the real degree of weathering of primary mineral grains under meteoric conditions, especially in lower weathering grade classes. Moreover, the frequent identification of Fe-Mn oxides and clay coatings of illuvial origin (rather than or in addition to those formed in situ), both at the macro- and microscale, may also explain an overestimation of the weathering degree with respect to field-based classifications. Finally, some apparent inconsistencies between field geomechanical responses and chemical weathering were interpreted as related to physical weathering processes (cryoclastism and thermoclastism), that lead to rock breakdown even when chemical weathering is not well developed. Hence, our study showed that particular caution is needed for evaluating weathering grades, because traditional field and geochemical-petrographic tools may be biased by inherited hydrothermal alteration, physical weathering and illuvial processes. On the basis of chronological constraints to soil formation obtained from a 42 ka-old volcanic input (mixed to granite parent materials) detected in the soil cover of the Sila Massif upland, a first attempt to estimate

  1. Geochemical characteristics and petrogenesis of phonolites and trachytic rocks from the České Středohoří Volcanic Complex, the Ohře Rift, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Ulrych, Jaromír; Řanda, Zdeněk; Erban, V.; Hegner, E.; Magna, T.; Balogh, K.; Frána, Jaroslav; Lang, Miloš; Novák, Jiří Karel

    224/225, May (2015), s. 256-271 ISSN 0024-4937 R&D Projects: GA AV ČR IAA3048201 Institutional support: RVO:67985831 ; RVO:61389005 Keywords : phonolite * trachyte * Sr–Nd–Li isotopes * Cenozoic alkaline volcanism * Ohře (Eger) Rift * Bohemian Massif Subject RIV: DD - Geochemistry Impact factor: 3.723, year: 2015

  2. Migmatization and low-pressure overprinting metamorphism as record of two pre-Cretaceous tectonic episodes in the Santander Massif of the Andean basement in northern Colombia (NW South America)

    Science.gov (United States)

    Zuluaga, C. A.; Amaya, S.; Urueña, C.; Bernet, M.

    2017-03-01

    The core of the Santander Massif in the northern Andes of Colombia is dominated by migmatitic gneisses with a 7.5 kbar. Lithologies are overprinted by low-pressure metamorphism, related to extensive Jurassic intrusions and linked with growth of cordierite and equilibration of low-pressure mineral assemblages, recorded metamorphic conditions are Pangaea.

  3. Les « granites à tablettes d'orthose » du Vivarais, témoins d'un magmatisme post-épaississement d'âge Dinantien inférieur ; identification d'une unité géologique Nord-Ouest-VivaraisThe orthoclase lath-rich granites from Vivarais, products of a Dinantian post-tectonic magmatism; identification of a NW-Vivarais geological unit

    Science.gov (United States)

    Briand, Bernard; Duthou, Jean-Louis; Guerrot, Catherine; Chenevoy, Maurice

    On the southern side of the Mont Pilat (eastern French Massif Central), an orthoclase-rich granite, which intrudes orthogneisses overlying a granito-migmatitic complex, gives a Dinantian age (RbSr age: 353±21 Ma; UPb age: 341+8/-5 Ma). Such a dating confirms the reality of a 'northwestern Vivarais' geological unit, whose metamorphic and granitic evolution cannot be assigned to a Late-Carboniferous event. These results impose a re-examination of both the 'granite du Velay' problematic and the geodynamic evolution of the eastern French Massif Central. To cite this article: B. Briand et al., C. R. Geoscience 334 (2002) 741-747.

  4. Seismotectonic significance of the 2008–2010 Walloon Brabant seismic swarm in the Brabant Massif, Belgium

    Science.gov (United States)

    Van Noten, Koen; Lecocq, Thomas; Shah, Anjana K.; Camelbeeck, Thierry

    2015-01-01

    Between 12 July 2008 and 18 January 2010 a seismic swarm occurred close to the town of Court-Saint-Etienne, 20 km SE of Brussels (Belgium). The Belgian network and a temporary seismic network covering the epicentral area established a seismic catalogue in which magnitude varies between ML -0.7 and ML 3.2. Based on waveform cross-correlation of co-located earthquakes, the spatial distribution of the hypocentre locations was improved considerably and shows a dense cluster displaying a 200 m-wide, 1.5-km long, NW-SE oriented fault structure at a depth range between 5 and 7 km, located in the Cambrian basement rocks of the Lower Palaeozoic Anglo-Brabant Massif. Waveform comparison of the largest events of the 2008–2010 swarm with an ML 4.0 event that occurred during swarm activity between 1953 and 1957 in the same region shows similar P- and S-wave arrivals at the Belgian Uccle seismic station. The geometry depicted by the hypocentral distribution is consistent with a nearly vertical, left-lateral strike-slip fault taking place in a current local WNW–ESE oriented local maximum horizontal stress field. To determine a relevant tectonic structure, a systematic matched filtering approach of aeromagnetic data, which can approximately locate isolated anomalies associated with hypocentral depths, has been applied. Matched filtering shows that the 2008–2010 seismic swarm occurred along a limited-sized fault which is situated in slaty, low-magnetic rocks of the Mousty Formation. The fault is bordered at both ends with obliquely oriented magnetic gradients. Whereas the NW end of the fault is structurally controlled, its SE end is controlled by a magnetic gradient representing an early-orogenic detachment fault separating the low-magnetic slaty Mousty Formation from the high-magnetic Tubize Formation. The seismic swarm is therefore interpreted as a sinistral reactivation of an inherited NW–SE oriented isolated fault in a weakened crust within the Cambrian core of

  5. Geologic map of the Alamosa 30’ × 60’ quadrangle, south-central Colorado

    Science.gov (United States)

    Thompson, Ren A.; Shroba, Ralph R.; Michael N. Machette,; Fridrich, Christopher J.; Brandt, Theodore R.; Cosca, Michael A.

    2015-10-15

    The Alamosa 30'× 60' quadrangle is located in the central San Luis Basin of southern Colorado and is bisected by the Rio Grande. The Rio Grande has headwaters in the San Juan Mountains of Colorado and ultimately discharges into the Gulf of Mexico 3,000 kilometers (km) downstream. Alluvial floodplains and associated deposits of the Rio Grande and east-draining tributaries, La Jara Creek and Conejos River, occupy the north-central and northwestern part of the map area. Alluvial deposits of west-draining Rio Grande tributaries, Culebra and Costilla Creeks, bound the Costilla Plain in the south-central part of the map area. The San Luis Hills, a northeast-trending series of flat-topped mesas and hills, dominate the landscape in the central and southwestern part of the map and preserve fault-bound Neogene basin surfaces and deposits. The Precambrian-cored Sangre de Cristo Mountains rise to an elevation of nearly 4,300 meters (m), almost 2,000 m above the valley floor, in the eastern part of the map area. In total, the map area contains deposits that record surficial, tectonic, sedimentary, volcanic, magmatic, and metamorphic processes over the past 1.7 billion years.

  6. Two new species of Indonemoura (Plecoptera: Nemouridae) from Yunnan Province of southwestern China.

    Science.gov (United States)

    Li, Weihai; Wu, Limin; Yang, Ding

    2017-02-09

    Two new species of the nemourid genus Indonemoura are described, Indonemoura curvispina sp. nov. and I. spirocornua sp. nov., from the Gaoligong Mountains of Yunnan Province of southwestern China. The taxonomic relationships with related species are discussed.

  7. Impact of the Gulf of California SST on simulating precipitation and crop productivity in the Southwestern United States

    Science.gov (United States)

    Kim, S.; Kim, J.; Prasad, A. K.; Stack, D. H.; El-Askary, H. M.; Kafatos, M.

    2012-12-01

    Like other ecosystems, agricultural productivity is substantially affected by climate factors. Therefore, accurate climatic data (i.e. precipitation, temperature, and radiation) is crucial to simulating crop yields. In order to understand and anticipate climate change and its impacts on agricultural productivity in the Southwestern United States, the WRF regional climate model (RCM) and the Agricultural Production Systems sIMulator (APSIM) were employed for simulating crop production. 19 years of WRF RCM output show that there is a strong dry bias during the warm season, especially in Arizona. Consequently, the APSIM crop model indicates very low crop yields in this region. We suspect that the coarse resolution of reanalysis data could not resolve the relatively warm Sea Surface Temperature (SST) in the Gulf of California (GC), causing the SST to be up to 10 degrees lower than the climatology. In the Southwestern United States, a significant amount of precipitation is associated with North American Monsoon (NAM). During the monsoon season, the low-level moisture is advected to the Southwestern United States via the GC, which is known to be the dominant moisture source. Thus, high-resolution SST data in the GC is required for RCM simulations to accurately represent a reasonable amount of precipitation in the region, allowing reliable evaluation of the impacts on regional ecosystems.and evaluate impacts on regional ecosystems. To evaluate the influence of SST on agriculture in the Southwestern U.S., two sets of numerical simulations were constructed: a control, using unresolved SST of GC, and daily updated SST data from the MODIS satellite sensor. The meteorological drivers from each of the 6 year RCM runs were provided as input to the APSIM model to determine the crop yield. Analyses of the simulated crop production, and the interannual variation of the meteorological drivers, demonstrate the influence of SST on crop yields in the Southwestern United States.

  8. Traditional ranching heritage and cultural continuity in the southwestern United States

    Science.gov (United States)

    Carol Raish; Alice M. McSweeney

    2008-01-01

    This study, conducted among ranchers on the Santa Fe and Carson National Forests in the Southwestern United States, examines the role of ranching in maintaining traditional heritage and cultural continuity. The mainly Hispanic ranching families of northern New Mexico first came into the region in 1598 with Spanish colonization. Many of the villages received community...

  9. Summer mistral at the exit of the Rhône valley

    Science.gov (United States)

    Drobinski, P.; Bastin, S.; Guenard, V.; Caccia, J. L.; Dabas, A. M.; Delville, P.; Protat, A.; Reitebuch, O.; Werner, C.

    2005-01-01

    The paper examines the three-dimensional structure and dynamics of the mistral at the Rhône valley exit on 28 June 2001. The mistral refers to a severe wind that develops along the Rhône valley in southern France. This summer mistral event was documented in the framework of the ESCOMPTE field experiment. The dynamical processes driving the circulation of the mistral in the Rhône valley and particularly wake formation and planetary boundary layer (PBL) inhomogeneity at the scale of Rhône valley delta are investigated. Several important data sources are used (airborne Doppler lidar, radiosondes and surface stations) as well as non-hydrostatic mesoscale simulations. This paper analyses experimentally, numerically and theoretically the mechanism of wake formation. It shows that the flow impinging on the Alpine range and the Massif Central becomes supercritical all along the ridge line, including the Rhône valley and continues to accelerate in the lee regions until a hydraulic jump occurs. It leads to the formation of wakes behind and close to the mountain peaks. Compared to the Massif Central wake, the origin of the western Alps wake is rather complicated. In this study, the observations and simulations suggest a combined wall separation/gravity wave breaking mechanism to explain the western Alps wake. Indeed, it is shown that in addition to the flow descending the western Alps slopes and experiencing a strong hydraulic jump, the point where the mistral flow separates from the eastern flank of the Rhône valley located at about 44°N is associated with a 'flank-shock' which is an oblique hydraulic jump (i.e.the downstream Froude number is supercritical). Wake formation in the lee of the Alps and the Massif Central causes large inhomogeneity of the PBL with differences between land and sea. In the Massif Central and western Alps wakes, the continental PBL is deeper (1.8 km) than in the mistral flow (1 km), which is consistent with a subcritical regime associated

  10. Ecological restoration of southwestern ponderosa pine ecosystems: A broad perspective

    Science.gov (United States)

    Allen, Craig D.; Savage, Melissa; Falk, Donald A.; Suckling, Kieran F.; Swetnam, Thomas W.; Schulke, Todd; Stacey, Peter B.; Morgan, Penelope; Hoffman, Martos; Klingel, Jon T.

    2002-01-01

    The purpose of this paper is to promote a broad and flexible perspective on ecological restoration of Southwestern (U.S.) ponderosa pine forests. Ponderosa pine forests in the region have been radically altered by Euro-American land uses, including livestock grazing, fire suppression, and logging. Dense thickets of young trees now abound, old-growth and biodiversity have declined, and human and ecological communities are increasingly vulnerable to destructive crown fires. A consensus has emerged that it is urgent to restore more natural conditions to these forests. Efforts to restore Southwestern forests will require extensive projects employing varying combinations of young-tree thinning and reintroduction of low-intensity fires. Treatments must be flexible enough to recognize and accommodate: high levels of natural heterogeneity; dynamic ecosystems; wildlife and other biodiversity considerations; scientific uncertainty; and the challenges of on-the-ground implementation. Ecological restoration should reset ecosystem trends toward an envelope of “natural variability,” including the reestablishment of natural processes. Reconstructed historic reference conditions are best used as general guides rather than rigid restoration prescriptions. In the long term, the best way to align forest conditions to track ongoing climate changes is to restore fire, which naturally correlates with current climate. Some stands need substantial structural manipulation (thinning) before fire can safely be reintroduced. In other areas, such as large wilderness and roadless areas, fire alone may suffice as the main tool of ecological restoration, recreating the natural interaction of structure and process. Impatience, overreaction to crown fire risks, extractive economics, or hubris could lead to widespread application of highly intrusive treatments that may further damage forest ecosystems. Investments in research and monitoring of restoration treatments are essential to refine

  11. Rapid acidification of mode and intermediate waters in the southwestern Atlantic Ocean

    NARCIS (Netherlands)

    Salt, L.A.; van Heuven, S.M.A.C.; Claus, M.E.; Jones, E.M.; de Baar, H.J.W.

    2015-01-01

    Observations along the southwestern Atlantic WOCE A17 line made during the Dutch GEOTRACESNL programme (2010-2011) were compared with historical data from 1994 to quantify the changes in the anthropogenic component of the total pool of dissolved inorganic carbon (Delta C-ant). Application of the

  12. Clusia nubium (Clusiaceae): a new species from cloud-forests of southwestern Ecuador

    DEFF Research Database (Denmark)

    Gustafsson, Mats; Borchsenius, Finn

    2016-01-01

    Clusia nubium from southwestern Ecuador is described as a species new to science. It grows as a hemiepiphyte in lower montane cloud forest. The species belongs to Clusia sect. Retinostemon, a largely Andean group characterized by male flowers with a resin-secreting synandrium of completely fused...

  13. Searching urinary tumor-associated proteins for bladder transitional cell carcinoma in southwestern Taiwan using gel-based proteomics

    Directory of Open Access Journals (Sweden)

    Chia-Cheng Su

    2016-12-01

    Conclusion: In this paper, 11 de-regulated proteins were observed in the urinary specimens of BTTC patients from the southwestern coast of Taiwan where Blackfoot disease is endemic and the unusually high incidence of BTTC in this area might attribute to high arsenic content in the drinking water. It is possible that long-term arsenic-induced alteration of these de-regulated proteins, most of which were extracellularmatrix – (ECM related proteins which may play roles in regulating the immune response, signal transduction and tumor invasions, might be involved in BTTC development in southwestern Taiwan.

  14. Morphological and interlayer geochemical studies on manganese nodules from the southwestern Carlsberg ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Rajamanickam, G.V.; Karisiddaiah, S.M.; Siddiquie, H.N.

    Mixed facies of manganese nodules from the southwestern Carlberg Ridge have been analysed for Mn, Fe, Ni, Cu, Co and Zn. Seventy one analyses including the averages presented for outer layer, inner layer and near-core material. Morphological studies...

  15. Monsoon-facilitated characteristics and transport of atmospheric mercury at a high-altitude background site in southwestern China

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2016-10-01

    Full Text Available To better understand the influence of monsoonal climate and transport of atmospheric mercury (Hg in southwestern China, measurements of total gaseous mercury (TGM, defined as the sum of gaseous elemental mercury, GEM, and gaseous oxidized mercury, GOM, particulate bound mercury (PBM and GOM were carried out at Ailaoshan Station (ALS, 2450 m a.s.l. in southwestern China from May 2011 to May 2012. The mean concentrations (± SD for TGM, GOM and PBM were 2.09 ± 0.63, 2.2 ± 2.3 and 31.3 ± 28.4 pg m−3, respectively. TGM showed a monsoonal distribution pattern with relatively higher concentrations (2.22 ± 0.58 ng m−3, p  =  0.021 during the Indian summer monsoon (ISM, from May to September and the east Asia summer monsoon (EASM, from May to September periods than that (1.99 ± 0.66 ng m−3 in the non-ISM period. Similarly, GOM and PBM concentrations were higher during the ISM period than during the non-ISM period. This study suggests that the ISM and the EASM have a strong impact on long-range and transboundary transport of Hg between southwestern China and south and southeast Asia. Several high TGM events were accompanied by the occurrence of northern wind during the ISM period, indicating anthropogenic Hg emissions from inland China could rapidly increase TGM levels at ALS due to strengthening of the EASM. Most of the TGM and PBM events occurred at ALS during the non-ISM period. Meanwhile, high CO concentrations were also observed at ALS, indicating that a strong south tributary of westerlies could have transported Hg from south and southeast Asia to southwestern China during the non-ISM period. The biomass burning in southeast Asia and anthropogenic Hg emissions from south Asia are thought to be the source of atmospheric Hg in remote areas of southwestern China during the non-ISM period.

  16. Effect of cement production on vegetation in a part of southwestern ...

    African Journals Online (AJOL)

    The impact of cement dust emissions from the factory of West African Portland Cement at Ewekoro in Southwestern Nigeria on the surrounding vegetation was investigated. Sample plots of 20 m x 20 m were established at 1 km intervals from the factory site up to a distance of 10 km intervals from the factory site up to a ...

  17. THE subfossil occurrence and paleoecological significance of small mammals at ankilitelo cave, southwestern Madagascar

    Science.gov (United States)

    Muldoon, K.M.; De Blieux, D. D.; Simons, E.L.; Chatrath, P.S.

    2009-01-01

    Small mammals are rarely reported from subfossil sites in Madagascar despite their importance for paleoenvironmental reconstruction, especially as it relates to recent ecological changes on the island. We describe the uniquely rich subfossil small mammal fauna from Ankilitelo Cave, southwestern Madagascar. The Ankilitelo fauna is dated to the late Holocene (???500 years ago), documenting the youngest appearances of the extinct giant lemur taxa Palaeopropithecus, Megaladapis, and Archaeolemur, in association with abundant remains of small vertebrates, including bats, tenrecs, carnivorans, rodents, and primates. The Ankilitelo fauna is composed of 34 mammalian species, making it one of the most diverse Holocene assemblages in Madagascar. The fauna comprises the 1 st report of the short-tailed shrew tenrec (Microgale brevicaudata) and the ring-tailed mongoose (Galidia elegans) in southwestern Madagascar. Further, Ankilitelo documents the presence of southwestern species that are rare or that have greatly restricted ranges today, such as Nasolo's shrew tenrec (M. nasoloi), Grandidier's mongoose (Galidictis grandidieri), the narrow-striped mongoose (Mungotictis decemlineata), and the giant jumping rat (Hypogeomys antimena). A simple cause for the unusual small mammal occurrences at Ankilitelo is not obvious. Synergistic interactions between climate change, recent fragmentation and human-initiated degradation of forested habitats, and community-level processes, such as predation, most likely explain the disjunct distributions of the small mammals documented at Ankilitelo. ?? 2009 American Society of Mammalogists.

  18. Trace element behavior during serpentinization/de-serpentinization of an eclogitized oceanic lithosphere: A LA-ICPMS study of the Lanzo ultramafic massif (Western Alps)

    OpenAIRE

    DEBRET, Baptiste; ANDREANI, Muriel; GODARD, Marguerite; NICOLLET, Christian; SCHWARTZ, Stéphane; LAFAY, Romain

    2013-01-01

    Serpentinites are one of the major components of the oceanic lithosphere and are stable in the slab and the mantle wedge up to 100-150 km depth in subduction zones. During oceanic mantle hydration and alteration, they trap trace and fluid mobile (FME: B, Li, As, Sb, Rb, Ba, Cs, Sr, U and Pb) elements that participate to elemental transfer occurring between the dehydrating slab and the mantle wedge in subduction context. The Lanzo massif is an eclogitized oceanic lithosphere that preserved its...

  19. Geography of spring landbird migration through riparian habitats in southwestern North America

    Science.gov (United States)

    Susan K. Skagen; Jeffrey F. Kelly; Charles van Riper III; Richard L. Hutto; Deborah M. Finch; David J. Krueper; Cynthia P. Melcher

    2005-01-01

    Migration stopover resources, particularly riparian habitats, are critically important to landbirds migrating across the arid southwestern region of North America. To explore the effects of species biogeography and habitat affinity on spring migration patterns, we synthesized existing bird abundance and capture data collected in riparian habitats of the borderlands...

  20. Assessment of grassland ecosystem conditions in the Southwestern United States. Vol. 1

    Science.gov (United States)

    Deborah M. Finch

    2004-01-01

    This report is volume 1 of a two-volume ecological assessment of grassland ecosystems in the Southwestern United States. Broadscale assessments are syntheses of current scientific knowledge, including a description of uncertainties and assumptions, to provide a characterization and comprehensive description of ecological, social, and economic components within an...

  1. Indian Monsoon Low-Pressure Systems Feed Up-and-Over Moisture Transport to the Southwestern Tibetan Plateau

    Science.gov (United States)

    Dong, Wenhao; Lin, Yanluan; Wright, Jonathon S.; Xie, Yuanyu; Xu, Fanghua; Xu, Wenqing; Wang, Yan

    2017-11-01

    As an integral part of the South Asian summer monsoon system, monsoon low-pressure systems (LPSs) bring large amounts of precipitation to agrarian north and central India during their passage across the subcontinent. In this study, we investigate the role of LPSs in supplying moisture from north and central India to the southwestern Tibetan Plateau (SWTP) and quantify the contribution of these systems to summer rainfall over the SWTP. The results show that more than 60% of total summer rainfall over the SWTP is related to LPS occurrence. LPSs are associated with a 15% rise in average daily rainfall and a 10% rise in rainy days over the SWTP. This relationship is maintained primarily through up-and-over transport, in which convectively lifted moisture over the Indian subcontinent is swept over the SWTP by southwesterly winds in the middle troposphere. LPSs play two roles in supplying up-and-over moisture transport. First, these systems elevate large amounts of water vapor and condensed water to the midtroposphere. Second, the circulations associated with LPSs interact with the background westerlies to induce southwesterly flow in the midtroposphere, transporting elevated moisture and condensate over the Himalayan Mountains. Our findings indicate that LPSs are influential in extending the northern boundary of the South Asian monsoon system across the Himalayas into the interior of the SWTP. The strength of this connection depends on both LPS characteristics and the configuration of the midtropospheric circulation, particularly the prevailing westerlies upstream of the SWTP.

  2. PRELIMINARY ANALYSIS OF THE EARTHQUAKE (MW 8.1 AND TSUNAMI OF APRIL 1, 2007, IN THE SOLOMON ISLANDS, SOUTHWESTERN PACIFIC OCEAN

    Directory of Open Access Journals (Sweden)

    Michael A. Fisher

    2007-01-01

    Full Text Available On April 1, 2007, a destructive earthquake (Mw 8.1 and tsunami struck the central Solomon Islands arc in the southwestern Pacific Ocean. The earthquake had a thrust-fault focal mechanism and occurred at shallow depth (between 15 km and 25 km beneath the island arc. The combined effects of the earthquake and tsunami caused dozens of fatalities and thousands remain without shelter. We present a preliminary analysis of the Mw-8.1 earthquake and resulting tsunami. Multichannel seismic- reflection data collected during 1984 show the geologic structure of the arc’s frontal prism within the earthquake’s rupture zone. Modeling tsunami-wave propagation indicates that some of the islands are so close to the earthquake epicenter that they were hard hit by tsunami waves as soon as 5 min. after shaking began, allowing people scant time to react.

  3. The late-Variscan peraluminous Valdepeñas pluton (southern Central Iberian Zone)

    Energy Technology Data Exchange (ETDEWEB)

    Errandonea-Martín, J.; Carracedo-sánchez, M.; Sarrionandia, F.; Santos Zalduegui, J.F.; García de Madinabeitia, S.; Gil-Ibarguchi, J.I.

    2017-07-01

    The Valdepeñas pluton is the easternmost outcrop of the Cáceres-Valdepeñas magmatic alignment (southern Central Iberian Zone). This massif is constituted by a cordierite-bearing porphyritic monzogranite and may be grouped within the so-called “Serie Mixta” granitoids. The Valdepeñas monzogranite is of magnesian [FeOt/(FeOt+MgO)~0.76], alkali-calcic [(Na2O+K2O)–CaO=7.8–8.5] and peraluminous (A/CNK=1.14–1.20). Multielemental- and REE-normalized patterns are comparable to those of similar rocks in the Nisa- Alburquerque-Los Pedroches magmatic alignment, and slightly differ from those of the Montes de Toledo batholith, both in the southern Central Iberian Zone. The U-Pb zircon age of 303±3Ma is consistent with the late-orogenic character of the intrusion and is in accordance with most of the granitic peraluminous intrusions in the southern Central Iberian Zone. 86Sr/87Sr300Ma ratios (0.707424–0.711253), εNd300Mavalues (-5.53 to -6.68) and whole-rock major and trace element compositions of the studied rocks, suggest that the parental magma of the Valdepeñas monzogranite could derive from a crustal metaigneous source. The U-Pb ages (552–650Ma) of inherited zircon cores found in Valdepeñas monzogranite samples match those often found in Lower Paleozoic metavolcanics and granitic orthogneisses of Central Iberia and, furthermore, point to Upper Neoproterozoic metaigneous basement rocks as possible protoliths at the magma source. Based on the solubility of monazite in peraluminous melts, the estimated emplacement temperature of the studied monzogranite is 742–762ºC. The results obtained in this work would contribute to a better understanding of the origin of the “Serie Mixta” granitoids.

  4. Land uplift in the Olkiluoto-Pyhaejaervi area, southwestern Finland, during the last 8000 years

    International Nuclear Information System (INIS)

    Eronen, M.; Glueckert, G.; Rantala, P.; Plassche, O. van de; Plicht, J. van der

    1995-12-01

    Land is rising in relation to sea level several millimetres per year on the coast of southwestern Finland. The aim of the study was to gather information about the land uplift process. Sediment samples were collected from 14 lakes lying at different altitudes in the area between Olkiluoto and Lake Pyhaejaervi in southwestern Finland to study the relative sea-level changes and land uplift. The present-day lakes had once been below the waters of the Baltic, but due to uplift they had been isolated from the sea one after another. The isolation points in the sediments were determined by preliminary diatom analyses. They show the change from brackish to fresh-water conditions, and these horizons were then dated by two radiocarbon assays. (37 refs., 18 figs., 1 tab.)

  5. Evolution of the Gondwanaland Archaean Shield: ion microprobe zircon dating and southwestern Australia/Wilkes Land, Antartica

    International Nuclear Information System (INIS)

    Lovering, J.F.; Comaford, D.J.

    1979-01-01

    The ion microprobe has been used to study 207 Pb/ 206 Pb ages on 20μm-sized sites on single zircon grains from coastal rocks on either side of the rift in the Gondwanaland Archaean Shield between southwestern Australia and Wilkes Land, Antarctica. The ages on individual sites on zircon grains from a variety of rock types from southwestern Australia show a range from 1600 m.y. to about 3400 m.y., with an inverse dependence on the uranium abundance at each site. Ages of zircons from rocks from the Antartic region show a range from 1600 m.y. to 3100 m.y

  6. High frequency measurement of P- and S-wave velocities on crystalline rock massif surface - methodology of measurement

    Science.gov (United States)

    Vilhelm, Jan; Slavík, Lubomír

    2014-05-01

    For the purpose of non-destructive monitoring of rock properties in the underground excavation it is possible to perform repeated high-accuracy P- and S-wave velocity measurements. This contribution deals with preliminary results gained during the preparation of micro-seismic long-term monitoring system. The field velocity measurements were made by pulse-transmission technique directly on the rock outcrop (granite) in Bedrichov gallery (northern Bohemia). The gallery at the experimental site was excavated using TBM (Tunnel Boring Machine) and it is used for drinking water supply, which is conveyed in a pipe. The stable measuring system and its automatic operation lead to the use of piezoceramic transducers both as a seismic source and as a receiver. The length of measuring base at gallery wall was from 0.5 to 3 meters. Different transducer coupling possibilities were tested namely with regard of repeatability of velocity determination. The arrangement of measuring system on the surface of the rock massif causes better sensitivity of S-transducers for P-wave measurement compared with the P-transducers. Similarly P-transducers were found more suitable for S-wave velocity determination then P-transducers. The frequency dependent attenuation of fresh rock massif results in limited frequency content of registered seismic signals. It was found that at the distance between the seismic source and receiver from 0.5 m the frequency components above 40 kHz are significantly attenuated. Therefore for the excitation of seismic wave 100 kHz transducers are most suitable. The limited frequency range should be also taken into account for the shape of electric impulse used for exciting of piezoceramic transducer. The spike pulse generates broad-band seismic signal, short in the time domain. However its energy after low-pass filtration in the rock is significantly lower than the energy of seismic signal generated by square wave pulse. Acknowledgments: This work was partially

  7. The birds of the alien Acacia thickets of the South-western Cape

    African Journals Online (AJOL)

    About 1876, the Cape Superintendent of Plantations began using the Australian Acacia cyanophylla and A. ... Strandveld; but 38 % of all nests recorded in the South-western Cape are in Acacia. S. senegalensis is .... of mixed exotic trees, often including some Acacia but also Eucalyptus, Pinus, Quercus,. Populus and other ...

  8. Description of a new moss frog from the south-western Cape (Anura ...

    African Journals Online (AJOL)

    A new species of moss frog, genus Arthroleptella, is described from the Kleinrivier mountains of the south-western Cape. It is morphologically indistinguishable from the other three species in the area. The four Cape species are allopatric, each has a unique male advertisement call, and preliminary molecular data shows ...

  9. Molybdenite-tungstenite association in the tungsten-bearing topaz greisen at Vítkov (Krkonoše-Jizera Crystalline Complex, Bohemian Massif): indication of changes in physico-chemical conditions in mineralizing system

    Czech Academy of Sciences Publication Activity Database

    Pašava, J.; Veselovský, F.; Drábek, M.; Svojtka, Martin; Pour, O.; Klomínský, J.; Škoda, R.; Ďurišová, Jana; Ackerman, Lukáš; Halodová, P.; Haluzová, Eva

    2015-01-01

    Roč. 60, č. 3 (2015), s. 149-161 ISSN 1802-6222 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : LA-ICP-MS * EMPA * molybdenite * tungstenite * transitional Mo–W and W–Mo disulfides * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.326, year: 2015

  10. Peeking out of the basins: looking for the Late Devonian Kellwasser Event in the open ocean in the Central Asian Orogenic Belt, southwestern Mongolia

    Science.gov (United States)

    Thomas, R. M., Jr.; Carmichael, S. K.; Waters, J. A.; Batchelor, C. J.

    2017-12-01

    Two of the top five most devastating mass extinctions in Earth's history occurred during the Late Devonian (419.2 Ma - 358.9 Ma), and are commonly associated with the black shale deposits of the Kellwasser and Hangenberg ocean anoxia events. Our understanding of these extinction events is incomplete partly due to sample bias, as 95% of the field sites studying the Late Devonian are limited to continental shelves and continental marine basins, and 77% of these sites are derived from the Euramerican paleocontinent. The Samnuuruul Formation at the Hoshoot Shiveetiin Gol locality (HSG), located in southwestern Mongolia, offers a unique opportunity to better understand global oceanic conditions during the Late Devonian. The HSG locality shows a continuous sequence of terrestrial to marine sediments on the East Junggar arc; an isolated, open-ocean island arc within the Central Asian Orogenic Belt (CAOB). Samples from this near shore locality consist of volcanogenic silts, sands and immature conglomerates as well as calc-alkalic basalt lava flows. Offshore sections contain numerous limestones with Late Devonian fossil assemblages. Preliminary biostratigraphy of the associated marine and terrestrial sequences can only constrain the section to a general Late Devonian age, but TIMS analysis of detrital zircons from volcanogenic sediments from the Samnuuruul Formation in localities 8-50 km from the site suggests a late Frasnian age (375, 376 Ma). To provide a more precise radiometric age of the HSG locality, zircon geochronology using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) will be performed at UNC-Chapel Hill. If the HSG section crosses the Frasnian-Famennian boundary, geochemical, mineralogical, and ichnological signatures of the Kellwasser Event are expected to be preserved, if the Kellwasser Event was indeed global in scope (as suggested by Carmichael et al. (2014) for analogous sites on the West Junggar arc in the CAOB). Black shale

  11. Aeolian deposition of Arabia and Somalia sediments on the southwestern continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Chauhan, O.S.

    Kaolinite, smectite, illite and chlorite as major clay minerals and palygorskite and gibbsite in minor quantities have been recorded from the slope of southwestern continental margin of India. Contribution of kaolinite, smectite and gibbsite is from...

  12. Transition from island-arc to passive setting on the continental margin of Gondwana: U-Pb zircon dating of Neoproterozoic metaconglomerates from the SE margin of the Teplá-Barrandian Unit, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Sláma, Jiří; Dunkley, D. J.; Kachlík, V.; Kusiak, M. A.

    2008-01-01

    Roč. 461, 1-4 (2008), s. 44-59 ISSN 0040-1951 Institutional research plan: CEZ:AV0Z30130516 Keywords : Bohemian Massif * Teplá–Barrandian Unit * Neoproterozoic * Armorican Terrane Assemblage * Gondwana * zircon dating Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.677, year: 2008

  13. Factorial's composition of Lake Abha, Southwestern Saudi Arabia

    International Nuclear Information System (INIS)

    El-Beheiry, M.A.H

    2007-01-01

    The study analyzes the vegetation along Lake Abha in Southwestern Saudi Arabia. A total of 42 plant species were recorded. The annuals decrease and the biennials and perennials increase along the moisture gradient form the terraces to the free-water zone. Six vegetation clusters were identified. The most important are clusters which were identified by the presence of the following species: Phragmites australis, Juncus punctorius, Typha domingensis, Cyperus rotundus, Datura innoxia, Cynodon dactylon, Cornulaca monacantha and Potamogeton nododsus. Each of these communities has been analyzed by classification and ordination techniques and its habitat described and discussed. (author)

  14. Cicada emergence in southwestern riparian forest: Influences of wildfire and vegetation composition

    Science.gov (United States)

    D. Max Smith; Jeffrey Kelly; Deborah M. Finch

    2006-01-01

    Annually emerging cicadas are a numerically and ecologically dominant species in Southwestern riparian forests. Humans have altered disturbance regimes that structure these forests such that floods are less common and wildfires occur more frequently than was historically the case. Impacts of these changes on primary consumers such as riparian cicadas are unknown....

  15. Summary (Songbird ecology in southwestern ponderosa pine forests: A literature review)

    Science.gov (United States)

    William M. Block; Deborah M. Finch; Joseph L. Ganey; William H. Moir

    1997-01-01

    Most ornithological studies in Southwestern ponderosa pine forests have yielded results that are applicable only to the specific location and particular conditions of the study areas (for example, Green 1979 and Hurlbert 1984). In addition, varying interpretation of similar study results by investigators has limited our ability to extend or synthesize research results...

  16. Critical Thinking Dispositions of Undergraduate Nursing Students and Nursing Faculty in Southwestern Nigeria

    Science.gov (United States)

    Ojewole, Foluso O.

    2013-01-01

    The purpose of this quantitative research study was to identify the critical thinking dispositions of undergraduate nursing students and nursing faculty in Southwestern Nigeria. Critical thinking dispositions are required for critical thinking skills. People who have critical thinking disposition exhibit seven traits: truth-seeking,…

  17. Spatial probability models of fire in the desert grasslands of the southwestern USA

    Science.gov (United States)

    Fire is an important driver of ecological processes in semiarid environments; however, the role of fire in desert grasslands of the Southwestern US is controversial and the regional fire distribution is largely unknown. We characterized the spatial distribution of fire in the desert grassland region...

  18. Postglacial recolonization in a cold climate specialist in western Europe: patterns of genetic diversity in the adder (Vipera berus) support the central-marginal hypothesis.

    Science.gov (United States)

    Ursenbacher, Sylvain; Guillon, Michaël; Cubizolle, Hervé; Dupoué, Andréaz; Blouin-Demers, Gabriel; Lourdais, Olivier

    2015-07-01

    Understanding the impact of postglacial recolonization on genetic diversity is essential in explaining current patterns of genetic variation. The central-marginal hypothesis (CMH) predicts a reduction in genetic diversity from the core of the distribution to peripheral populations, as well as reduced connectivity between peripheral populations. While the CMH has received considerable empirical support, its broad applicability is still debated and alternative hypotheses predict different spatial patterns of genetic diversity. Using microsatellite markers, we analysed the genetic diversity of the adder (Vipera berus) in western Europe to reconstruct postglacial recolonization. Approximate Bayesian Computation (ABC) analyses suggested a postglacial recolonization from two routes: a western route from the Atlantic Coast up to Belgium and a central route from the Massif Central to the Alps. This cold-adapted species likely used two isolated glacial refugia in southern France, in permafrost-free areas during the last glacial maximum. Adder populations further from putative glacial refugia had lower genetic diversity and reduced connectivity; therefore, our results support the predictions of the CMH. Our study also illustrates the utility of highly variable nuclear markers, such as microsatellites, and ABC to test competing recolonization hypotheses. © 2015 John Wiley & Sons Ltd.

  19. Geology of drill hole USW VH-2, and structure of Crater Flat, southwestern Nevada

    International Nuclear Information System (INIS)

    Carr, W.J.; Parrish, L.D.

    1985-01-01

    A 1219 meter (4000 ft) drill hole in Crater Flat shows the absence of buried Pliocene or Quaternary volcanic rocks, and penetrates a section of Timber Mountain, Paintbrush, and the upper part of the Crater Flat Tuffs, similar to that exposed adjacent to Crater Flat. A prominent negative aeromagnetic anomaly between the drill hole and Bare Mountain is attributed to a westward thickening section of a reversely magnetized Miocene basalt. The relatively shallow depth of this basalt in the west-central part of Crater Flat indicates that no large amount of tectonic movement has occurred in approximately the last 10 m.y. Massive brecciated wedges of Paleozoic rocks are penetrated in two stratigraphic intervals in the drill hole; the older one, between the Tiva Canyon Member of the Paintbrush Tuff and the Rainier Mesa Member of the Timber Mountain Tuff, correlates with the time of maximum faulting east of Crater Flat in the Yucca Mountain area. The younger slide masses are correlated with a large slide block of probable late Miocene age exposed along the southwestern rim of Crater Flat. The structural pattern and style buried beneath central and western Crater Flat is deduced to be similar to that exposed at Yucca Mountain, but less developed. The major fault system controlling the steep east face of Bare Mountain, though probably still active, is believed to have developed mainly as a result of caldera collapse between 13 and 14 m.y. ago. Relations between faulting and four episodes of basalt eruption in the Crater Flat area strongly suggest contemporaneity of the two processes. 17 refs., 2 figs., 3 tabs

  20. Micro-FTIR and EPMA Characterisation of Charoite from Murun Massif (Russia

    Directory of Open Access Journals (Sweden)

    Maria Lacalamita

    2018-01-01

    Full Text Available Combined micro-Fourier transform infrared (micro-FTIR and electron probe microanalyses (EPMA were performed on a single crystal of charoite from Murun Massif (Russia in order to get a deeper insight into the vibrational features of crystals with complex structure and chemistry. The micro-FTIR study of a single crystal of charoite was collected in the 6000–400 cm−1 at room temperature and after heating at 100°C. The structural complexity of this mineral is reflected by its infrared spectrum. The analysis revealed a prominent absorption in the OH stretching region as a consequence of band overlapping due to a combination of H2O and OH stretching vibrations. Several overtones of the O-H and Si-O stretching vibration bands were observed at about 4440 and 4080 cm−1 such as absorption possibly due to the organic matter at about 3000–2800 cm−1. No significant change due to the loss of adsorbed water was observed in the spectrum obtained after heating. The occurrence of well-resolved water bending vibration bands at about 1595 and 1667 cm−1 accounts for more than one structural water molecule as expected by charoite-90 polytype structure model from literature. The chemical composition of the studied crystal is close to the literature one.

  1. Unraveling the Quaternary river incision in the Moselle valley (Rhenish Massif, Germany): new insights from cosmogenic nuclide dating (10Be/26Al) of the Main Terrace complex

    Science.gov (United States)

    Rixhon, Gilles; Cordier, Stéphane; Harmand, Dominique; May, Simon Matthias; Kelterbaum, Daniel; Dunai, Tibor; Binnie, Steven; Brückner, Helmut

    2014-05-01

    Throughout the whole river network of the Rhenish Massif, the terrace complex of the so-called Main Terrace forms the morphological transition between a wide upper palaeovalley (plateau valley) and a deeply incised lower valley. The youngest level of this Main Terrace complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature in the terrace flight; it is often used as a reference level to identify the start of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). The latter probably reflects the major tectonic pulse that affected the whole Massif and was related to an acceleration of the uplift rates (Demoulin & Hallot, 2009). The Main terraces are particularly well preserved in the lower Moselle valley and are characterized by a constant absolute elevation of their base along a 150 km-long reach. Despite that various hypotheses have been proposed to explain this horizontality (updoming, faulting...), all studies assumed an age of ca. 800 ka for the YMT, mainly based on the questionable extrapolation of palaeomagnetic data obtained in the Rhine valley. Therefore, a reliable chronological framework is still required to unravel the spatio-temporal characteristics of the Pleistocene evolution of the Moselle valley. In this study, we apply cosmogenic nuclide dating (10Be/26Al) to fluvial sediments pertaining to the Main Terrace complex or to the upper Middle Terraces. Several sites along the lower Moselle were sampled following two distinct sampling strategies: (i) depth profiles where the original terrace (palaeo-)surface is well preserved and did not experience much postdepositional burial (e.g., loess cover); and (ii) the isochron technique where the sediment thickness exceeds 3 m. Cosmogenic nuclide ages recently obtained for three rivers in the Meuse catchment in the western Rhenish Massif demonstrated that the Main Terraces were younger than expected and their abandonment was diachronic along the

  2. Petrological, Geochemical and Sr–Nd–O Isotopic Constraints on the Origin of Garnet and Spinel Pyroxenites from the Moldanubian Zone of the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Svojtka, Martin; Ackerman, Lukáš; Medaris Jr., G.; Hegner, E.; Valley, J. W.; Hirajima, T.; Jelínek, E.; Hrstka, Tomáš

    2016-01-01

    Roč. 57, č. 5 (2016), s. 897-920 ISSN 0022-3530 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100131203 Program:Program interní podpory projektů mezinárodní spolupráce AV ČR Institutional support: RVO:67985831 Keywords : garnet and spinel pyroxenites * Bohemian Massif * Sr, Nd, and oxygen isotopes * trace elements * subduction Subject RIV: DD - Geochemistry Impact factor: 3.280, year: 2016

  3. Buruli Ulcer Disease and Its Association with Land Cover in Southwestern Ghana.

    Directory of Open Access Journals (Sweden)

    Jianyong Wu

    2015-06-01

    Full Text Available Buruli ulcer (BU, one of 17 neglected tropical diseases, is a debilitating skin and soft tissue infection caused by Mycobacterium ulcerans. In tropical Africa, changes in land use and proximity to water have been associated with the disease. This study presents the first analysis of BU at the village level in southwestern Ghana, where prevalence rates are among the highest globally, and explores fine and medium-scale associations with land cover by comparing patterns both within BU clusters and surrounding landscapes.We obtained 339 hospital-confirmed BU cases in southwestern Ghana between 2007 and 2010. The clusters of BU were identified using spatial scan statistics and the percentages of six land cover classes were calculated based on Landsat and Rapid Eye imagery for each of 154 villages/towns. The association between BU prevalence and each land cover class was calculated using negative binomial regression models. We found that older people had a significantly higher risk for BU after considering population age structure. BU cases were positively associated with the higher percentage of water and grassland surrounding each village, but negatively associated with the percent of urban. The results also showed that BU was clustered in areas with high percentage of mining activity, suggesting that water and mining play an important and potentially interactive role in BU occurrence.Our study highlights the importance of multiple land use changes along the Offin River, particularly mining and agriculture, which might be associated with BU disease in southwestern Ghana. Our study is the first to use both medium- and high-resolution imagery to assess these changes. We also show that older populations (≥ 60 y appear to be at higher risk of BU disease than children, once BU data were weighted by population age structures.

  4. Abundance of birds in the oak savannas of the southwestern United States

    Science.gov (United States)

    Wendy D. Jones; Carlton M. Jones; Peter F. Ffolliott; Gerald J. Gottfried

    2005-01-01

    Oak ecosystems of the Southwestern United States are important habitats for a variety of wildlife species. Information is available on the abundance and habitat preferences of some species inhabiting the more densely structured oak woodlands, but little information is available on these topics for the comparatively open oak savannas. Studies are underway to alleviate...

  5. IODP Expedition 340T: Borehole Logging at Atlantis Massif Oceanic Core Complex

    Directory of Open Access Journals (Sweden)

    Donna Blackman

    2013-03-01

    Full Text Available Integrated Ocean Drilling Program (IODP Expedition 340T returned to the 1.4-km-deep Hole U1309D at Atlantis Massif to carry out borehole logging including vertical seismic profiling (VSP. Seismic, resistivity, and temperature logs were obtained throughout the geologic section in the footwall of this oceanic core complex. Reliable downhole temperature measurements throughout and the first seismic coverage of the 800–1400 meters below seafloor (mbsf portionof the section were obtained. Distinct changes in velocity, resistivity, and magnetic susceptibility characterize the boundaries of altered, olivine-rich troctolite intervals within the otherwise dominantly gabbroic se-quence. Some narrow fault zones also are associated with downhole resistivity or velocity excursions. Small deviations in temperature were measured in borehole fluid adjacent to known faults at 750 mbsf and 1100 mbsf. This suggests that flow of seawater remains active along these zones of faulting and rock alteration. Vertical seismic profile station coverage at zero offsetnow extends the full length of the hole, including the uppermost 150 mbsf, where detachment processes are expected to have left their strongest imprint. Analysis of wallrock properties, together with alteration and structural characteristics of the cores from Site U1309, highlights the likely interplay between lithology, structure, lithospheric hydration, and core complex evolution.

  6. The Taavinunnanen gabbro massif. A compilation of results from geological, geophysical and hydrogeological investigations

    International Nuclear Information System (INIS)

    Gentzschein, B.; Tullborg, E.L.

    1985-01-01

    The gabbro massif at Taavinunnanen, northern Sweden, is one of the study sites which has been investigated by the Swedish Nuclear Fuel and Waste Management Co (SKB) in order to study different geological environments within the scope of the long-range program for final disposal of spent nuclear fuel. A 700 metres long borehole was drilled within the gabbro. Regional geophysics, geological mapping, petrographical studies, mineralogical studies of rock-forming materials and of fracture fillings as well as hydrogeological tests were carried out. The gabbro shows primary differentiation. Thus, the composition varies from gabbroic to ultrabasic. The gabbro body is intersected by severeal granite dikes. These dikes exhibit a higher hydraulic conductivity and a higher fracture frequency than the gabbro. Comparison of hydraulic conductivity and fracture frequency in the gabbro itself indicates a high degree of sealing of the fractures mainly caused by smectites. Calcite is almost lacking down to a depth of 75 metres, indicating a relatively rapid transport of surface waters down to this depth. With 27 refs. (author)

  7. K-Ar ages of the low-grade metamorphic rocks in the Altar massif, Northwest Sonora, Mexico

    International Nuclear Information System (INIS)

    Hayama, Yoshikazu; Shibata, Ken; Takeda, Hideo.

    1984-01-01

    The K-Ar ages of low-grade regional metamorphism, granodiorite intrusion and its contact metamorphism were studied in the Altar massif of Northwest Sonora, Mexico. The results gave the ages of 55 Ma for metamorphic hornblende and 15 to 17 Ma for mica of metamorphic rocks and granodiorite. About the meaning of these discordant ages and the too young ages of 15 to 17 Ma against the previously presented data, we pointed out the following two possibilities; 1) the contact effect of the Miocene granodiorite on the regional metamorphic rocks of the Laramide phase, 2) both regional metamorphism and granodiorite intrusion took place during the Laramide phase, whereas the young ages, 15 to 17 Ma, show the time of temperature release after the low-angle thrust movement, which is well known in the hinterland of the Sevier orogenic belt in Nevada and Utah. (author)

  8. Southwestern willow flycatchers (Empidonax traillii extimus) in a grazed landscape: factors influencing brood parasitism

    Science.gov (United States)

    Katherine M. Brodhead; Scott H. Stoleson; Deborah M. Finch

    2007-01-01

    Brood parasitism by Brown-headed Cowbirds (Molothrus ater; hereafter "cowbirds") is an important factor contributing to the endangered status of the Southwestern Willow Flycatcher (Empidonax traillii extimus, hereafter "flycatcher"). We report on factors that influence brood parasitism on the flycatcher using...

  9. The rockfall observatory in the Reintal, Wetterstein Massif, German Alps

    Science.gov (United States)

    Schöpa, Anne; Turowski, Jens M.; Hovius, Niels

    2017-04-01

    The Reintal is an Alpine valley in the Wetterstein Massif close to the Zugspitze, Germany's highest mountain. Due to the variety of active geomorphic processes, including rockfalls off the steep limestone cliffs, debris flows, and snow avalanches, and the river Partnach, the Reintal has been the field area of many geomorphological and hydrological research campaigns over the last few decades. In 2014, the Geomorphology Section of the GFZ Potsdam started to install a monitoring network to detect and classify rockfalls in the Reintal. The network includes six seismic stations, optical and infrared cameras, and two weather stations measuring air and rock temperature, air pressure and relative humidity, precipitation, wind speed and direction, and solar radiation. The continuous observations of the network are supplemented by repeated field campaigns including terrestrial laser scans of a prominent rockfall niche at the Hochwanner mountain. The about 1,500 m high north face of the Hochwanner experienced the detachment of a 2.8 Mio m3 rockfall about 500 years ago that created the so-called Steingerümpel (German for rock debris deposit) and dammed the river Partnach. The cliff still shows high rockfall activity, and an 80,000 m3 block can be expected to fall in the near future. In this contribution, the layout of the observatory and details of the seismic network centered around the Hochwanner north face are described. Furthermore, the network data of a severe thunderstorm event in June 2016, that triggered many rockfalls and debris flows in the Reintal, is presented.

  10. Southwestern Institute of Physics: Annual Report 1998

    International Nuclear Information System (INIS)

    1999-10-01

    The main achievements of controlled nuclear fusion research are presented for Southwestern Institute of Physics in 1998 year. With the establishment and operation of two auxiliary heating systems (NBI, ICRH), the HL-1M Tokamak is equipped with main auxiliary heating and current driving systems such as NBI, ECRH, ICRH and LHCD etc. . In addition, a variety of advanced fueling system, i.e. , multi-shot pellet and supersonic molecular beam injection, the first wall processing technologies of boronization, siliconization and lithiumization as well as more than 20 diagnostic facilities with partial space-time resolution capability have been established on the device. The construction of a larger Tokamak with divertors, the HL-2A, and its complementary systems are being carried out

  11. Lower Brioverian formations (Upper Proterozoic) of the Armorican Massif (France): geodynamic evolution of source areas revealed by sandstone petrography and geochemistry

    Science.gov (United States)

    Dabard, Marie Pierre

    1990-11-01

    Formations with interbedded cherts constitute an important part of the Lower Brioverian succession (Upper Proterozoic age) in the Armorican Massif (northwest France). These formations are composed of shale-sandstone alternations with interbedded siliceous carbonaceous members. Petrographic and geochemical study of the detrital facies shows that these rocks are compositionally immature. The wackes are rich in lithic fragments (volcanic fragments: 3-20% modal; sedimentary and metamorphic fragments: 0-7% modal) and in feldspar (5-16%). From the geochemical point of view, they are relatively enriched in Fe 2+MgO (about 5.5%) and in alkalis with {Na 2O }/{K 2O } ratios greater than 1. The CaO contents are low (about 0.3%). Slightly negative Eu anomalies are observed ( {Eu}/{Eu ∗} = 0.8 ). Their chemical compositions are in agreement with a dominantly acidic source area with deposition in a continental active margin setting. Compared with other Upper Proterozoic deposits of the Armorican Massif, the interbedded-chert formations appear rather similar to other deposits in North Brittany which accumulated in an intra-arc or back-arc basin environment. The formations with interbedded cherts are interpreted as having been deposited during an early stage of magmatic arc activity (around 640-630 Ma ago) in an immature marginal basin. The clastic supply to these formations is derived in part from early volcanic products (acidic to intermediate) which are linked to subduction beneath the North Armorican Domain. Another component is inherited from the reworking of 2000 Ma old basement relics. The opening of the back-arc domain, with associated basaltic volcanism, would bring about a progressive displacement of the interbedded-chert depositional basin towards the continental margin.

  12. Migration of 137Cs artificial radionuclide in the valley of the Takhtakushuk river of the Degelen massif

    International Nuclear Information System (INIS)

    Panitskij, A.V.

    2005-01-01

    Study of horizontal and vertical radionuclide distribution in the valley of the Takhtakushuk River of the 'Degelen' Massif is carried out in the framework of ecological and biological investigations of soil and plant cover within radioactive contaminated areas, and radionuclide migration in biological chain 'soil - plant - animal'. For the first time, the pool-type method was used in the studies of soil of the valley that allows tracing solid and liquid substances migrating by means of surface and soil drainage from its head to final part. This paper presents some physical and chemical properties of the study landscape's soils, radionuclide content in soil genetic horizons of the valley. The study results showed that major mass of 137 Cs radionuclide is sorbed by soil humus and fine-dispersed clay particles of grass soils within the valley. (author)

  13. Geochemical and petrological constraints on mantle composition of the Ohře(Eger) rift, Bohemian Massif: peridotite xenoliths from the České Středohoří Volcanic complex and northern Bohemia

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Medaris Jr., G.; Špaček, P.; Ulrych, Jaromír

    2015-01-01

    Roč. 104, č. 8 (2015), s. 1957-1979 ISSN 1437-3254 R&D Projects: GA ČR GA205/09/1170 Institutional support: RVO:67985831 Keywords : Bohemian Massif * mantle * metasomatism * Ohře(Eger) rift * xenolith Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.133, year: 2015

  14. Long-lived large-scale deformation under Central and Western Europe

    Science.gov (United States)

    Qorbani, Ehsan; Bokelmann, Götz

    2016-04-01

    We investigate the past and present-day deformation pattern under Central and Western Europe through seismic anisotropy. We use all SK(K)S splitting results that have been so far presented for this region and compile an image of upper mantle deformation. A large-scale deformation pattern emerges where NE-SW fast orientations under the Aegean are smoothly changing to NW-SE beneath the Hellenides-Dinarides conjunction. NW-SE is the dominant pattern under the whole Carpathian-Pannonian region. Towards Bohemia, the pattern rotates to E-W. The rotation continues until the Rhine valley, and it continues further within the Alps, all the way to Southern France. Outside the Alpine-deformation-influenced region, we observe a jump in fast orientation, between the Ardennes and the Massif Central in France, where the fast axis orientation is back to NW-SE. That anisotropy pattern may correlate with the arcuate shape of Variscan orogeny. It agrees with the Rheic suture line, and the boarders of two main tectonic units of European Variscides, Saxothuringian and Muldanubian. Previous studies on upper mantle anisotropy have interpreted and related such pattern mainly to frozen-in deformation from the past tectonic episodes. This has so far remained ambiguous though. Here we assess the relation between deformation at depth and shallower structure, as evidenced by stress field and topography. We discuss the presence of a long-lived large-scale upper mantle deformation, which has been acting ever since the Cambrian in different orogenic phases (Caledonian, Variscan, Alpine).

  15. Geochemical aspects of alkaline massif of Banhadao, PR, Brazil

    International Nuclear Information System (INIS)

    Ruberti, E.; Gomes, C.B.; Dutra, C.V.

    1987-01-01

    The alkaline massif of Banhadao, located near Cerro Azul, State of Parana, southern Brazil, occupies an area of about 8 Km 2 and is constituted by three magnetic associations: a group of mesocratic to leucocratic coarse nepheline syenites (NeS) (melanite NeS, NeS I, and light reddish and grey varieties of NeS II); a second group of medium to fine-grained ultrabasic to basic rocks (phlogopite melteigites and petrologically related malignites and feldspar-melanite ijolites); and a group of fine-grained to aphanitic phonolotic dikes, cutting NeS. The rocks of the complex are miaskitic, showing low concentrations of trace elements (V, Th and mainly REE), lack of rare metal silicates, and relative abundance of apatite and sphene. NeS are distinguished by a differentiation trend in which highly differentiated end members are enriched in alkalis and Al 2 O 3 , with decrease in MgO, FeO (total), CaO and TiO 2 . The less differentiated melanite-rich rocks show higher concentrations in Zr, Nb, Y and V. Phlogopite melteigites and associated rocks show the highest contents of MgO, FeO (total), CaO and TiO 2 , and the lowest concentration of alkalis and Al 2 O 3 ; they are significantly enriched in Ba and are the only rocks with detectable amounts of Ni, Cu and Cr. The phonolites are chemically similar to NeS. The Banhadao rocks were probably formed during successive intrusions of two different magmas types. The source of NeS and phonolites was probably a nephelinitic magma, while phlogopite melteigites and related rocks were probably derived from an alkali-enriched ferromagnesian magna. Both parent magmas probably derived by melting of rocks of the lower crust or upper mantle. (author) [pt

  16. A Climatology of Tropospheric CO over the Central and Southeastern United States and the Southwestern Pacific Ocean Derived from Space, Air, and Ground-based Infrared Interferometer Spectra

    Science.gov (United States)

    McMillian, W. Wallace; Strow, L. Larrabee; Revercomb, H.; Knuteson, R.; Thompson, A.

    2003-01-01

    This final report summarizes all research activities and publications undertaken as part of NASA Atmospheric Chemistry and Modeling Analysis Program (ACMAP) Grant NAG-1-2022, 'A Climatology of Tropospheric CO over the Central and Southeastern United States and the Southwestern Pacific Ocean Derived from Space, Air, and Ground-based Infrared Interferometer Spectra'. Major project accomplishments include: (1) analysis of more than 300,000 AERI spectra from the ARM SGP site yielding a 5-year (1998-2002) timeseries of CO retrievals from the Lamont, OK AERI; (2) development of a prototype CO profile retrieval algorithm for AERI spectra; (3) validation and publication of the first CO retrievals from the Scanning High-resolution Interferometer Sounder (SHIS); and (4) development of a prototype AERI tropospheric O3 retrieval algorithm. Compilation and publication of the 5-year Lamont, OK timeseries is underway including a new collaboration with scientists at the Lawrence Berkeley National Laboratory. Public access to this data will be provided upon article submission. A comprehensive CO analysis of the archive of HIS spectra of remains as the only originally proposed activity with little progress. The greatest challenge faced in this project was motivating the University of Wisconsin Co-Investigators to deliver their archived HIS and AERIOO data along with the requisite temperature and water vapor profiles in a timely manner. Part of the supplied HIS dataset from ASHOE may be analyzed as part of a Master s Thesis under a separate project. Our success with the SAFARI 2000 SHIS CO analysis demonstrates the utility of such aircraft remote sensing data given the proper support from the instrument investigators. In addition to the PI and Co-I s, personnel involved in this CO climatology project include one Post Doctoral Fellow, one Research Scientist, two graduate students, and two undergraduate students. A total of fifteen presentations regarding research related to this

  17. Long-term trends in restoration and associated land treatments in the southwestern United States

    Science.gov (United States)

    Copeland, Stella M.; Munson, Seth M.; Pilliod, David S.; Welty, Justin L.; Bradford, John B.; Butterfield, Bradley J.

    2018-01-01

    Restoration treatments, such as revegetation with seeding or invasive species removal, have been applied on U.S. public lands for decades. Temporal trends in these management actions have not been extensively summarized previously, particularly in the southwestern United States where invasive plant species, drought, and fire have altered dryland ecosystems. We assessed long-term (1940–2010) trends in restoration using approximately 4,000 vegetation treatments conducted on Bureau of Land Management lands across the southwestern United States. We found that since 1940, the proportions of seeding and vegetation/soil manipulation (e.g. vegetation removal or plowing) treatments have declined, while the proportions of prescribed burn and invasive species treatments have increased. Treatments in pinyon-juniper and big sagebrush communities declined in comparison to treatments in desert scrub, creosote bush, and riparian woodland communities. Restoration-focused treatment objectives increased relative to resource extraction objectives. Species richness and proportion of native species used in seeding treatments also increased. Inflation-adjusted costs per area rose 750% for vegetation/soil manipulation, 600% for seeding, and 400% for prescribed burn treatments in the decades from 1981 to 2010. Seeding treatments were implemented in warmer and drier years when compared to the climate conditions of the entire study period and warmer and wetter years relative to several years before and after the treatment. These results suggest that treatments over a 70-year period on public lands in the southwestern United States are shifting toward restoration practices that are increasingly large, expensive, and related to fire and invasive species control.

  18. Bedrock instability of underground storage systems in the Czech Republic, Central Europe

    Czech Academy of Sciences Publication Activity Database

    Nováková, Lucie; Brož, Milan; Záruba, J.; Sosna, K.; Najser, J.; Rukavičková, L.; Franěk, J.; Rudajev, V.

    2016-01-01

    Roč. 13, č. 2 (2016), s. 315-325 ISSN 1672-7975 R&D Projects: GA MPO(CZ) FR-TI1/367 Institutional support: RVO:67985891 ; RVO:67985530 Keywords : underground storage * instability * seismicity * Bohemian Massif Subject RIV: DD - Geochemistry Impact factor: 0.796, year: 2016

  19. New knowledge and research methodologies of tectonics of the Small Carpathians

    International Nuclear Information System (INIS)

    Hoffman, M.

    2009-01-01

    The aim of this study was to reveal deformation processes in the Bratislava Massif and compare them to other areas. Specifically, data were compared with the locations and Bystricka and Dubna Skala in the northern part of Lucanska Mala Fatra and Central Krivanska Small mountain. Also cracks were the aim of this study because they can contribute to the knowledge of the dynamics of geological processes in the history of the massif, but they do not have much explanatory value of their own accord.

  20. Stelletta hajdui, a new species from the southwestern Atlantic (Porifera, Choristida, Ancorinidae)

    NARCIS (Netherlands)

    Lerner, Cléa; Mothes, Beatriz

    1999-01-01

    A new species of Stelletta from the southwestern Atlantic, Stelletta hajdui sp.n. is described from the slope off Rio Grande do Sul State coast, Brazil (32°24'S, 50°15'W) (Fig.1). The material studied was dredged up at the depth of 200m by the R/V Atlântico Sul, during “Projeto Talude” run by

  1. Variability and trends in dry day frequency and dry event length in the southwestern United States

    Science.gov (United States)

    McCabe, Gregory J.; Legates, David R.; Lins, Harry F.

    2010-01-01

    Daily precipitation from 22 National Weather Service first-order weather stations in the southwestern United States for water years 1951 through 2006 are used to examine variability and trends in the frequency of dry days and dry event length. Dry events with minimum thresholds of 10 and 20 consecutive days of precipitation with less than 2.54 mm are analyzed. For water years and cool seasons (October through March), most sites indicate negative trends in dry event length (i.e., dry event durations are becoming shorter). For the warm season (April through September), most sites also indicate negative trends; however, more sites indicate positive trends in dry event length for the warm season than for water years or cool seasons. The larger number of sites indicating positive trends in dry event length during the warm season is due to a series of dry warm seasons near the end of the 20th century and the beginning of the 21st century. Overall, a large portion of the variability in dry event length is attributable to variability of the El Niño–Southern Oscillation, especially for water years and cool seasons. Our results are consistent with analyses of trends in discharge for sites in the southwestern United States, an increased frequency in El Niño events, and positive trends in precipitation in the southwestern United States.

  2. Oil and Gas Development in Southwestern Wyoming - Energy Data and Services for the Wyoming Landscape Conservation Initiative (WLCI)

    Science.gov (United States)

    Biewick, Laura

    2009-01-01

    The purpose of this report is to explore current oil and gas energy development in the area encompassing the Wyoming Landscape Conservation Initiative. The Wyoming Landscape Conservation Initiative is a long-term science-based effort to ensure southwestern Wyoming's wildlife and habitat remain viable in areas facing development pressure. Wyoming encompasses some of the highest quality wildlife habitats in the Intermountain West. At the same time, this region is an important source of natural gas. Using Geographic Information System technology, energy data pertinent to the conservation decision-making process have been assembled to show historical oil and gas exploration and production in southwestern Wyoming. In addition to historical data, estimates of undiscovered oil and gas are included from the 2002 U.S. Geological Survey National Assessment of Oil and Gas in the Southwestern Wyoming Province. This report is meant to facilitate the integration of existing data with new knowledge and technologies to analyze energy resources development and to assist in habitat conservation planning. The well and assessment data can be accessed and shared among many different clients including, but not limited to, an online web-service for scientists and resource managers engaged in the Initiative.

  3. How do we know how much groundwater is stored in south-western Cape mountains?

    CSIR Research Space (South Africa)

    Midgley, JJ

    2001-07-01

    Full Text Available Isotopes of water (D, O-18) in rain and streams were used to obtain an estimate of the amount of ground water in the south-western Cape Mountains. It was assumed that the groundwater reservoir is well-mixed and that the water isotope signals...

  4. Stone heat treatment in the Early Mesolithic of southwestern Germany: Interpretation and identification.

    Directory of Open Access Journals (Sweden)

    Patrick Schmidt

    Full Text Available The Early Mesolithic of southwestern Germany, the so-called Beuronian (9600-7100 BC, is a period of important transformations in the way people lived, in their subsistence and in the stone tools they produced. One of the perhaps most spectacular re-inventions of that time is heat treatment of stones prior to their manufacture into tools. Although heat treatment has been understood as one of the defining characteristics of the Beuronian of southwestern Germany, and although its existence has been known for almost 30 years now, relatively few systematic studies on it are available. In this paper, we present such a study, aiming to shed light on two questions: (1 what technique and heating parameters were used in the Beuronian and (2 how reliable are the macroscopic proxies traditionally used to identify heat treatment in this context? We investigate these questions using a non-destructive archaeometric technique for measuring past heating temperatures of heat-treated stones and a quantitative surface roughness analysis aiming to understand the relations between surface aspect and heat treatment. These methods are applied to 46 Jurassic chert artefacts from the site Helga-Abri located in the Swabian Alb region of southwestern Germany. Our results document that an opportunistic low-investment procedure was used to heat stone, probably relying on the use of the above-ground part of regular camp-fires. We also found that the traditionally used macroscopic criteria, such as colour and surface gloss, cannot be unambiguously used to identify heat treatment in assemblages made from Jurassic chert. These findings have important implications for our understanding of the Beuronian lithic chaîne opératoire in terms of the investment in time and resources necessary, and for the refinement of archaeological techniques used to identify heat treatment in the Mesolithic of the Swabian Alb.

  5. Stone heat treatment in the Early Mesolithic of southwestern Germany: Interpretation and identification.

    Science.gov (United States)

    Schmidt, Patrick; Spinelli Sanchez, Océane; Kind, Claus-Joachim

    2017-01-01

    The Early Mesolithic of southwestern Germany, the so-called Beuronian (9600-7100 BC), is a period of important transformations in the way people lived, in their subsistence and in the stone tools they produced. One of the perhaps most spectacular re-inventions of that time is heat treatment of stones prior to their manufacture into tools. Although heat treatment has been understood as one of the defining characteristics of the Beuronian of southwestern Germany, and although its existence has been known for almost 30 years now, relatively few systematic studies on it are available. In this paper, we present such a study, aiming to shed light on two questions: (1) what technique and heating parameters were used in the Beuronian and (2) how reliable are the macroscopic proxies traditionally used to identify heat treatment in this context? We investigate these questions using a non-destructive archaeometric technique for measuring past heating temperatures of heat-treated stones and a quantitative surface roughness analysis aiming to understand the relations between surface aspect and heat treatment. These methods are applied to 46 Jurassic chert artefacts from the site Helga-Abri located in the Swabian Alb region of southwestern Germany. Our results document that an opportunistic low-investment procedure was used to heat stone, probably relying on the use of the above-ground part of regular camp-fires. We also found that the traditionally used macroscopic criteria, such as colour and surface gloss, cannot be unambiguously used to identify heat treatment in assemblages made from Jurassic chert. These findings have important implications for our understanding of the Beuronian lithic chaîne opératoire in terms of the investment in time and resources necessary, and for the refinement of archaeological techniques used to identify heat treatment in the Mesolithic of the Swabian Alb.

  6. Palaeozoic amalgamation of Central Europe: new results from recent geological and geophysical investigations

    Czech Academy of Sciences Publication Activity Database

    Winchester, J. A.; Floyd, P. A.; Crowley, Q. G.; Piasecki, M. A. J.; Lee, M. K.; Pharaoh, T. C.; Williamson, P.; Banka, D.; Verniers, J.; Samuelsson, J.; Bayer, U.; Marotta, A. M.; Lamarche, J.; Franke, W.; Dörr, W.; Valverde-Vaquero, P.; Giese, U.; Vecoli, M.; Thybo, H.; Laigle, M.; Scheck, M.; Maluski, H.; Marheine, D.; Noble, S. R.; Parrish, R. R.; Evans, J.; Timmerman, H.; Gerdes, A.; Guterch, A.; Grad, M.; Cwojdzinski, S.; Cymerman, Z.; Kozdroj, W.; Kryza, R.; Alexandrowski, P.; Mazur, S.; Štědrá, V.; Kotková, J.; Belka, Z.; Patočka, František; Kachlík, V.

    2002-01-01

    Roč. 360, 1-4 (2002), s. 5-21 ISSN 0040-1951 R&D Projects: GA AV ČR IAA3111102 Keywords : Palaeozoic Gondwana margin * Trans-European Suture Zone * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.409, year: 2002

  7. The Cambrian-Ordovician rocks of Sonora, Mexico, and southern Arizona, southwestern margin of North America (Laurentia): chapter 35

    Science.gov (United States)

    Page, William R.; Harris, Alta C.; Repetski, John E.; Derby, James R.; Fritz, R.D.; Longacre, S.A.; Morgan, W.A.; Sternbach, C.A.

    2013-01-01

    Cambrian and Ordovician shelf, platform, and basin rocks are present in Sonora, Mexico, and southern Arizona and were deposited on the southwestern continental margin of North America (Laurentia). Cambrian and Ordovician rocks in Sonora, Mexico, are mostly exposed in scattered outcrops in the northern half of the state. Their discontinuous nature results from extensive Quaternary and Tertiary surficial cover, from Tertiary and Mesozoic granitic batholiths in western Sonora, and from widespread Tertiary volcanic deposits in the Sierra Madre Occidental in eastern Sonora. Cambrian and Ordovician shelf rocks were deposited as part of the the southern miogeocline on the southwestern continental margin of North America.

  8. Disrupted bone metabolism in contaminant-exposed white storks (Ciconia ciconia) in southwestern Spain

    International Nuclear Information System (INIS)

    Smits, Judit E.; Bortolotti, Gary R.; Baos, Raquel; Jovani, Roger; Tella, Jose L.; Hoffmann, Walter E.

    2007-01-01

    In 1998, the Aznalcollar mine tailings dyke in southwestern Spain broke, flooding the Agrio-Guadiamar river system with acid tailings up to the borders of one of the largest breeding colonies of white storks in the western Palearctic, Dehesa de Abajo. Over the following years, a high proportion of nestlings developed leg defects not seen before the spill, prompting this study. Nestlings with deformed legs had significantly lower plasma phosphorous (P) and higher Ca:P ratios than non-deformed cohorts in the first two years, but in the third year, when more, younger birds were studied, plasma P ranged from much higher to much lower in the affected colony compared with reference birds. Coefficients of variation for phosphorous were 19% and 60%, in reference and contaminated colonies, respectively. Storks from the contaminated colony were unable to control P levels and Ca:P ratios within the narrow limits necessary for normal bone development. - Since a large mine tailings spill near a stork colony in southwestern Spain, nestlings had leg deformities and could not control serum phosphorous levels and Ca:P ratios

  9. Disrupted bone metabolism in contaminant-exposed white storks (Ciconia ciconia) in southwestern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Smits, Judit E. [Department of Veterinary Pathology, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK S7N 5B4 (Canada)]. E-mail: judit.smits@usask.ca; Bortolotti, Gary R. [Department of Biology, University of Saskatchewan, Saskatoon, 52 Campus Drive, SK S7N 5B4 (Canada)]. E-mail: gary.bortolotti@usask.ca; Baos, Raquel [Estacion Biologica de Donana, C.S.I.C., 41013 Sevilla (Spain)]. E-mail: raquel@ebd.csic.es; Jovani, Roger [Estacion Biologica de Donana, C.S.I.C., 41013 Sevilla (Spain); Tella, Jose L. [Estacion Biologica de Donana, C.S.I.C., 41013 Sevilla (Spain); Hoffmann, Walter E. [University of Illinois, College of Veterinary Medicine, Champagne-Urbana, IL (United States)]. E-mail: wally@uiuc.edu

    2007-01-15

    In 1998, the Aznalcollar mine tailings dyke in southwestern Spain broke, flooding the Agrio-Guadiamar river system with acid tailings up to the borders of one of the largest breeding colonies of white storks in the western Palearctic, Dehesa de Abajo. Over the following years, a high proportion of nestlings developed leg defects not seen before the spill, prompting this study. Nestlings with deformed legs had significantly lower plasma phosphorous (P) and higher Ca:P ratios than non-deformed cohorts in the first two years, but in the third year, when more, younger birds were studied, plasma P ranged from much higher to much lower in the affected colony compared with reference birds. Coefficients of variation for phosphorous were 19% and 60%, in reference and contaminated colonies, respectively. Storks from the contaminated colony were unable to control P levels and Ca:P ratios within the narrow limits necessary for normal bone development. - Since a large mine tailings spill near a stork colony in southwestern Spain, nestlings had leg deformities and could not control serum phosphorous levels and Ca:P ratios.

  10. Microfossils in the Ordovician erratic boulders from South-western Finland

    Directory of Open Access Journals (Sweden)

    Nõlvak, J.

    1995-12-01

    Full Text Available Chitinozoans, ostracods and acritarchs found in four glacially transported limestone boulders from the south-western coast of Finland have been studied in order to test the usefulness of these microfossil groups in age determinations. Also rare specimens of conodonts, inarticulated brachiopods and foraminifers were found. Baltic limestone (or Östersjö limestone was the most problematic, because only fossils with calcitic or phosphatic shells are preserved. It is concluded that the boulders identified correlate with the Uhaku and Rakvere stages of the Middle Ordovician.

  11. Scale Dependence of Land Atmosphere Interactions in Wet and Dry Regions as Simulated with NU-WRF over the Southwestern and Southeast US

    Science.gov (United States)

    Zhou, Yaping; Wu, Di; Lau, K.- M.; Tao, Wei-Kuo

    2016-01-01

    Large-scale forcing and land-atmosphere interactions on precipitation are investigated with NASA-Unified WRF (NU-WRF) simulations during fast transitions of ENSO phases from spring to early summer of 2010 and 2011. The model is found to capture major precipitation episodes in the 3-month simulations without resorting to nudging. However, the mean intensity of the simulated precipitation is underestimated by 46% and 57% compared with the observations in dry and wet regions in the southwestern and south-central United States, respectively. Sensitivity studies show that large-scale atmospheric forcing plays a major role in producing regional precipitation. A methodology to account for moisture contributions to individual precipitation events, as well as total precipitation, is presented under the same moisture budget framework. The analysis shows that the relative contributions of local evaporation and large-scale moisture convergence depend on the dry/wet regions and are a function of temporal and spatial scales. While the ratio of local and large-scale moisture contributions vary with domain size and weather system, evaporation provides a major moisture source in the dry region and during light rain events, which leads to greater sensitivity to soil moisture in the dry region and during light rain events. The feedback of land surface processes to large-scale forcing is well simulated, as indicated by changes in atmospheric circulation and moisture convergence. Overall, the results reveal an asymmetrical response of precipitation events to soil moisture, with higher sensitivity under dry than wet conditions. Drier soil moisture tends to suppress further existing below-normal precipitation conditions via a positive soil moisture-land surface flux feedback that could worsen drought conditions in the southwestern United States.

  12. Lu-Hf geochronology on cm-sized garnets using microsampling: New constraints on garnet growth rates and duration of metamorphism during continental collision (Menderes Massif, Turkey)

    Science.gov (United States)

    Schmidt, Alexander; Pourteau, Amaury; Candan, Osman; Oberhänsli, Roland

    2015-12-01

    This study shows Lu-Hf geochronology of zoned garnet crystals contained in mica schists from the southern Menderes Massif, Turkey. Selected samples are four 3-5 cm large garnet megacrysts of which several consecutive garnet shells have been sampled with a micro-saw and analyzed for dating. The results are used to extract growth rates of garnet, and also to improve the time constraint for Alpine-aged overprint of the Pan-African basement in the Menderes Massif. Lu-Hf ages of the sampled garnet shells are determined by two-point garnet-only isochrons using the garnets' Lu-depleted rim compositions. This yields a consistent decrease of age information from core to rim segments of individual garnet crystals and the calculated isochron ages propose a time frame of growth between 42.6 ± 1.9 and 34.8 ± 3.1 Ma. Major element profiles in the investigated garnets characterize zoning patterns indicative of prograde conditions: Rayleigh fractionated bell-shaped Mn and decreasing Fe/(Fe + Mg) are recorded by the garnets' core to rim compositions. Therefore the obtained Lu-Hf ages record timing of early prograde growth for the cores of the garnets. Two of the large garnet crystals also yield isochron ages of 58.83 ± 0.69 and 50.16 ± 0.84 Ma in their innermost cores, which appear to record an early nucleation event. This view, however, is not in concordance with the observed major element profiles of these garnets, and therefore is interpreted with caution. Termination of the garnet growth period is determined through the calculation of radial growth rates based on the size of the garnets and the Lu-Hf ages obtained for consecutive shells. Extrapolation of these rates potentially constrains the total duration for garnet growth terminating at 31 ± 6 Ma. Comparison of the growth rates calculated for individual crystals shows a variety of slow and fast growing garnets, and similar results have been previously obtained with the Rb-Sr and Sm-Nd isotope systems. The new data

  13. Interpretation of magnetic data of the Laachach gossan (central Jebilets, Morocco): mining implications; Interpretation des donnees magnetiques du chapeau de fer de Laachach (Jebilets centrales, Maroc): Implications minieres

    Energy Technology Data Exchange (ETDEWEB)

    Jaffal, M.; El Goumi, N; Hibti, M.; Adama Dairou, A.; Kchikach, A.; Manar, A.

    2010-07-01

    In the hercynian massif of Central Jebilets (Morocco), outcrop a large number of gossans which sometimes top economical orebodies (Kettara, Draa Sfar, etc.). The present study is devoted to the interpretation of magnetic data covering one of these iron hats, located near of the Laachach village, at about thirty kilometres north-westward of Marrakech. The magnetic map of Laachach highlights several anomalies which coincide with the outcrop of the gossan. Detailed analysis of reduced to the pole data allow us to conclude that these anomalies may be due to submeridian magnetic structures cut by a set of dextral transverse faults. These structures are generally dipping westward but they can be locally subvertical. The Euler deconvolution of the magnetic data gives moderately deeping solutions (22 to 254 m). The quantitative interpretation of the two principal magnetic anomalies highlighted in the study area lead to better characterising of the deep structure of the Laachach magnetic bodies, that may correspond to massive sulphide occurrences, according to the geological and mining context of the study area. The two modelled bodies constitute priority recognition targets for any mining exploration program to be carried out on the Laachach site. (Author).

  14. Multiple glacial culminations from the Lateglacial to the late Holocene in central and southern Peru (Invited)

    Science.gov (United States)

    Licciardi, J. M.; Schaefer, J. M.; Rodbell, D. T.; Stansell, N.; Schweinsberg, A.; Finkel, R. C.; Zimmerman, S. R.

    2013-12-01

    Fluctuations in small tropical mountain glaciers serve as sensitive indicators of variations in past and present-day climate. Most of the world's modern tropical glaciers reside in the Peruvian Andes, where a growing number of well-dated glacial records have recently been developed. As additional records are documented, regional patterns of late Pleistocene to Holocene glacial activity have begun to emerge. Here we present a compilation of new and previously obtained 10Be surface exposure ages from boulders on well-preserved moraine successions in two glaciated Andean ranges: the Cordillera Vilcabamba of southern Peru (13°20'S, 72°32'W) and the Huaguruncho massif (10°32'S, 75°56'W), located in central Peru ~450 km northwest of the Vilcabamba. A high-resolution composite chronology that merges >100 10Be measurements on moraine sequences in five glaciated drainages of the Cordillera Vilcabamba reveals the occurrence of at least five discrete glacial culminations from the Lateglacial to the late Holocene. At the Huaguruncho massif, >20 10Be exposure ages obtained from moraine sequences in a south-facing cirque indicate at least three major glacial stages spanning the Lateglacial to the Little Ice Age. The moraine ages at Huaguruncho are broadly correlative with the Vilcabamba moraine chronologies, with some dated moraine belts exhibiting geomorphic expressions that closely resemble those of their coeval counterparts in the Vilcabamba. A recurring finding in both field areas is a mismatch between basal radiocarbon ages from bog and lake sediments and 10Be exposure ages on outboard moraines, which enclose the depositional basins. These age discrepancies suggest that cosmogenic 10Be production rates scaled to high altitudes in the tropics are substantially lower than previous estimates. While we anticipate that future refinements to scaled isotope production rates may significantly affect correlation of 10Be exposure ages in the high Andes with ages derived from

  15. Vulnerability of field crops to midcentury temperature changes and yield effects in the Southwestern USA

    Science.gov (United States)

    Increased temperatures in the Southwestern United States will impact future crop production via multiple pathways. We used four methods to provide an illustrative analysis of midcentury temperature impacts to eight field crops. By midcentury, cropland area thermally suitable for maize cultivation is...

  16. Microbial inputs in coffee (Coffea arabica L.) production systems, southwestern Ethiopia

    OpenAIRE

    Muleta, Diriba

    2007-01-01

    Arabica coffee is the key cash crop and top mainstay of the Ethiopian economy and requires sustainable production methods. Southwestern natural forests, the site of this study, are believed to be the centre of origin and diversity for Coffea arabica and still harbour wild Arabica coffee that may serve as an important gene pool for future breeding. Cost reductions, sustainability and quality improvement are now the major priorities in coffee production systems and require organic growing of co...

  17. Changes in Gambel oak densities in southwestern ponderosa pine forests since Euro-American settlement

    Science.gov (United States)

    Scott R. Abella; Peter Z. Fulé

    2008-01-01

    Densities of small-diameter ponderosa pine (Pinus ponderosa) trees have increased in southwestern ponderosa pine forests during a period of fire exclusion since Euro-American settlement in the late 1800s. However, less well known are potential changes in Gambel oak (Quercus gambelii) densities during this period in these forests....

  18. Gamma ray spectrometry and radon emissions in soils from the Piquiri Syenite Massif region (Encruzilhada do Sul e Cachoeira do Sul, RS); Espectrometria de raios gama e emissao de radonio em solos da regiao do Macico Sienitico Piquiri (Cachoeira do Sul e Encruzilhada do Sul, RS)

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Mujalli, Gibran, E-mail: gibran.romero.mujalli@uni-hamburg.de [Institute for Geology, University of Hamburg (Germany); Roisenberg, Ari, E-mail: ari.roisenberg@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Geociencias. Departamento de Mineralogia e Petrologia

    2016-05-15

    This study was focused in performing a gamma radiation survey and measurements of radon concentration in soils from the Piquiri Syenite Massif, an intrusion located at central area of the Rio Grande do Sul State. This intrusion has alkaline affiliation with high concentrations of uranium in accessory minerals as zircon, sphene, apatite, and others. The gamma radiation measurements were made considering a grid with squares about 2 km side each, using the gamma spectrometer RS-125, obtaining counts per second (cps), dose rate (DR) and concentrations of K, eU and eTh. Moreover, measurements of {sup 220}Rn and {sup 222}Rn in soil were made using the AlphaGUARD equipment. The counts per second values obtained in this study range from 130 to 1045, the dose rate from 28.9 nSv/h to 424.6 nSv/h, the K concentration from 0.5 % to 8.3 %, the eU concentration from 0.8 ppm to 25.8 ppm, and the eTh concentration from 3.0 ppm to 99.2 ppm. The distribution of K defines with relatively precision the lithological contacts of the Piquiri Syenite Massif and between the two main facies of the intrusion (Main and Marginal Facies). The Main Facies of the syenite contains the highest concentrations of eTh, while the highest concentrations of eU were measured in the north area of this facies. The {sup 220}Rn and {sup 222}Rn concentrations range from 10 kBq/m{sup 3} to 550 kBq/m{sup 3} and from 5 kBq/m{sup 3} to 400 kBq/m{sup 3}, respectively, in the Main and Marginal Facies. The high values of radon measured in Main Facies of the Piquiri Syenite Intrusion may indicate high potential risk to the health of inhabitants in the area. (author)

  19. Genetic diversity of Ascaris in southwestern Uganda

    DEFF Research Database (Denmark)

    Betson, Martha; Nejsum, Peter; Llewellyn-Hughes, Julia

    2012-01-01

    . Microsatellite analysis using eight loci provided evidence for high gene flow between worm populations from the two villages but comparing these worms with others obtained in a prior study on Unguja, Zanzibar, confirmed little genetic exchange and mixing of worm populations between the two areas. By adding......Despite the common occurrence of ascariasis in southwestern Uganda, helminth control in the region has been limited. To gain further insights into the genetic diversity of Ascaris in this area, a parasitological survey in mothers (n=41) and children (n=74) living in two villages, Habutobere...... and Musezero, was carried out. Adult Ascaris worms were collected from infected individuals by chemo-expulsion using pyrantel pamoate treatment. Genetic diversity within these worms was assessed by inspection of DNA sequence variation in a mitochondrial marker and length polymorphism at microsatellite loci...

  20. Significance of Zr-in-Rutile Thermometry for Deducing the Decompression P–T Path of a Garnet–Clinopyroxene Granulite in the Moldanubian Zone of the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Usuki, T.; Iizuka, Y.; Hirajima, T.; Svojtka, Martin; Lee, H.-Y.

    2017-01-01

    Roč. 58, č. 6 (2017), s. 1173-1198 ISSN 0022-3530 Grant - others:Program interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100131203 Program:Program interní podpory projektů mezinárodní spolupráce AV ČR Institutional support: RVO:67985831 Keywords : Bohemian Massif * P–T path * Zr-in-rutile thermometry * high-pressure granulite * continental collision * garnet–clinopyroxene barometry Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 3.280, year: 2016

  1. A new perspective on the generation of the 2016 M6.4 Meilung earthquake, southwestern Taiwan

    Science.gov (United States)

    Wang, Z.

    2017-12-01

    In order to investigate the likely generation mechanism of the 2016 M6.4 Meilung earthquake, a large number of high-quality travel times from P- and S-wave source-receiver pairs are used jointly in this study to invert three-dimensional (3-D) seismic velocity (Vp, Vs) and Poisson's ratio structures at high resolution. We also calculated crack density, saturate fracture, and bulk-sound velocity from our inverted Vp, Vs, and s models. In this way, multi-geophysical parameter imaging revealed that the 2016 Meilung earthquake occurred along a distinctive edge portion exhibiting high-to-low variations in these parameters in both horizontal and vertical directions across the hypocenter. We consider that a slow velocity and high-Poisson ratio body that has high-crack density and somewhat high-saturate fracture anomalies above the hypocenter under the coastal plain represents fluids contained in the young fold-and-thrust belt relative to the passive Asian continental margin in southwestern Taiwan. Intriguing, a continuous low Vp and Vs zone with high Poisson ratio, crack density and saturate fracture anomalies across the Laonung and Chishan faults is also clearly imaged in the northwestern upper crust beneath the coastal plain and western foothills as far as the southeastern lower crust under the central range. We therefore propose that this southeastern extending weakened zone was mainly the result of a fluid intrusion either from the young fold-and-thrust belt associated with the passive Asian continental margin in the shallow crust or the subducted Eurasian continental (EC) plate in the lower crust and uppermost mantle. We suggest that fluid intrusion into the upper Oligocene to Pleistocene shallow marine and clastic shelf units of the Eurasian continental crust and/or the relatively thin uppermost part of the transitional Pleistocene-Holocene foreland due to the subduction of the EC plate along the deformation front played a key role in earthquake generation in

  2. A new perspective on the generation of the 2016 M6.7 Kaohsiung earthquake, southwestern Taiwan

    Science.gov (United States)

    Wang, Zhi

    2017-04-01

    In order to investigate the likely generation mechanism of the 2016 M6.7 Kaohsiung earthquake, a large number of high-quality travel times from P- and S-wave source-receiver pairs are used jointly in this study to invert three-dimensional (3-D) seismic velocity (Vp, Vs) and Poisson's ratio structures at high resolution. We also calculated crack density, saturate fracture, and bulk-sound velocity from our inverted Vp, Vs, and σgodels. In this way, multi-geophysical parameter imaging revealed that the 2016 Kaohsiung earthquake occurred along a distinctive edge portion exhibiting high-to-low variations in these parameters in both horizontal and vertical directions across the hypocenter. We consider that a slow velocity and high-σ body that has high ɛ and somewhat high ζ anomalies above the hypocenter under the Coastal Plain represents fluids contained in the young fold-and-thrust belt associated with the passive Asian continental margin in southwestern Taiwan. Intriguing, a continuous low Vp and Vs zone with high Poisson's ratio, crack density and saturate fracturegnomalies across the Laonung and Chishan faults is also clearly imaged in the northwestern upper crust beneath the Coastal Plain and Western Foothills as far as the southeastern lower crust under the Central Range. We therefore propose that this southeastern extending weakened zone was mainly the result of a fluid intrusion either from the young fold-and-thrust belt the shallow crust or the subducted Eurasian continental (EC) plate in the lower crust and uppermost mantle. We suggest that fluid intrusion into the upper Oligocene to Pleistocene shallow marine and clastic shelf units of the Eurasian continental crust and/or the relatively thin uppermost part of the transitional Pleistocene-Holocene foreland due to the subduction of the EC plate along the deformation front played a key role in earthquake generation in southwestern Taiwan. Such fluid penetration would reduce Vp, and Vs while increasing

  3. Ecology and management of oak woodlands and savannas in the southwestern Borderlands Region

    Science.gov (United States)

    Gerald J. Gottfried; Peter F. Ffolliott

    2013-01-01

    Management of the Madrean oak woodlands and the less dense and ecologically different oak savannas must be based on sound ecological information. However, relatively little is known about the Madrean oak ecosystems in spite of the fact that they cover about 80,000 km2 in the southwestern United States and northern Mexico. Emory oak (Quercus emoryi), the dominant tree...

  4. Stream channel designs for riparian and wet meadow rangelands in the southwestern United States

    Science.gov (United States)

    Roy Jemison; Daniel G. Neary

    2000-01-01

    Inappropriate land uses have degraded wetland and riparian ecosystems throughout the Southwestern United States. In 1996, the Cibola National Forest in New Mexico implemented a channel relocation project, as part of a road improvement project, to determine the feasibility of restoring wet meadow and riparian ecosystems degraded by inappropriately located roads and...

  5. Avian nest box selection and nest success in burned and unburned southwestern riparian forests

    Science.gov (United States)

    D. Max Smith; Jeffrey F. Kelly; Deborah M. Finch

    2007-01-01

    Riparian forest communities in the southwestern United States were historically structured by a disturbance regime of annual flooding. In recent decades, however, frequency of flooding has decreased and frequency of wildfires has increased. Riparian forests provide important breeding habitat for a large variety of bird species, and the effects of this altered...

  6. Radiometric ages of some igneous rocks from the southern and southwestern coalfields of New South Wales

    International Nuclear Information System (INIS)

    Carr, P.F.; Facer, R.A.

    1980-01-01

    Samples from six igneous rock units of the Southern and Southwestern Coalfields (Sydney Basin) of New South Wales have been dated using the K-Ar radiometric technique. The following ages were determined: a dolerite from Towradgi, 243 +- 10 MY; a dolerite from a diamond-drill hole at Sutton Forest, 202 +- 8 MY; the Bong Bong Basalt, 190 +- 8 MY; the Good Dog Lamprophyre, 101 +- 4 MY; a teschenite from South Bulli coal mine 74.0 +- 3.6 MY; and a dolerite from Robertson, 63.8 +- 3.2 MY. Combination of these new ages wth previously-published ages indicates that igneous activity in the Southern and Southwestern Coalfields occurred during four discrete periods of time - Middle-to-Late Permian; Late Triassic to Early Jurassic; mid-Cretaceous (only the Good Dog Lamprophyre has yielded such an age); and latest Cretaceous to Late Oligocene

  7. Disposal and reclamation of southwestern coal and uranium wastes

    International Nuclear Information System (INIS)

    Wewerka, E.M.

    1979-01-01

    The types of solid wastes and effluents produced by the southwestern coal and uranium mining and milling industries are considered, and the current methods for the disposal and reclamation of these materials discussed. The major means of disposing of the solid wastes from both industries is by land fill or in some instances ponding. Sludges or aqueous wastes are normally discharged into settling and evaporative ponds. Basic reclamation measures for nearly all coal and uranium waste disposal sites include solids stabilization, compacting, grading, soil preparation, and revegetation. Impermeable liners and caps are beginning to be applied to disposal sites for some of the more harmful coal and uranium waste materials

  8. Radon, carbon dioxide and fault displacements in central Europe related to the Tohoku earthquake

    International Nuclear Information System (INIS)

    Briestensky, M.; Stemberk, J.; Rowberry, M.D.; Thinova, L.; Knejflova, Z.; Praksova, R.

    2014-01-01

    Tectonic instability may be measured directly using extensometers installed across active faults or it may be indicated by anomalous natural gas concentrations in the vicinity of active faults. This paper presents the results of fault displacement monitoring at two sites in the Bohemian Massif and Western Carpathians. These data have been supplemented by radon monitoring in the Mladec Caves and by carbon dioxide monitoring in the Zbrasov Aragonite Caves. A significant period of tectonic instability is indicated by changes in the fault displacement trends and by anomalous radon and carbon dioxide concentrations. This was recorded around the time of the catastrophic M W = 9.0 Tohoku Earthquake, which hit eastern Japan on 11 March 2011. It is tentatively suggested that the Tohoku Earthquake in the Pacific Ocean and the unusual geodynamic activity recorded in the Bohemian Massif and Western Carpathians both reflect contemporaneous global tectonic changes. (authors)

  9. A critique of massification of higher education in Poland and the United States: Mass-media discourse analysis

    Directory of Open Access Journals (Sweden)

    Łukasz Stankiewicz

    2017-01-01

    Full Text Available The nearly universal access to higher education (HE in developed countries was once praised as a great democratic achievement, and a basis for both economic development and social mobility. After the onset of the 2008 recession, the narratives changed considerably. The most radical critics of HE propose a partial “deschooling” of society by reversing the process of massification. This paper aims to present a critical discourse analysis (CAD of the “don’t go to college” discourse that became popular in Poland and the United States. I trace the differences in the way the decision to go to college is conceptualized in Poland and the U.S to the differences in dominant political ideologies – democratic and egalitarian in the U.S., paternalistic and conservative in Poland. I also show how recent changes in the actual HE systems put those ideologies at odds with the educational realities of both countries.

  10. A preliminary spatial-temporal study of some soil characteristics in the calcareous massif of Sicó, Portugal.

    Science.gov (United States)

    Torres, Maria Odete; Neves, Maria Manuela

    2016-04-18

    The mountainous massif of Sicó, in the centre of Portugal, is an extensive area composed of calcareous Jurassic formations. Hillside calcareous soils, with high pH, present chemical restrictions to support plant growth and are subjected to important erosion processes leading to their degradation if not protected by vegetation. In a first year of study some soil physicochemical characteristics have been measured in some geo-referenced locations of a larger design experiment and an exploratory spatial analysis has been performed. The objective of this study was to present some suggestions in order to give sustainable phosphorus fertiliser recommendations aiming to establish pastures in these soils and thus support traditional livestock activity. Ten years apart, those soil characteristics have been measured again in the same locations and comparisions have been made. The objective was to understand the variability of the soil properties under study in order to better adequate the fertiliser soil management regarding the area restoration.

  11. Palaeogeographic evolution of the marine Middle Triassic marine Germanic Basin changements - With emphasis on the carbonate tidal flat and shallow marine habitats of reptiles in Central Pangaea

    Science.gov (United States)

    Diedrich, Cajus G.

    2009-01-01

    More than seventy-five vertebrate track-sites have been found in Central Europe in 243-246.5 m.y. old Triassic coastal intertidal to sabkha carbonates. In the western part of the very flat Triassic intracontinental Germanic Basin, the carbonate strata contain at least 22 laterally extensive track horizons (called megatracksites). In contrast, in the eastern part of the basin only six megatracksites extended to near the centre of the Basin during marine low stands. Marine ingression and the development of extensive coastal marine environments began during the Aegean (Anisian) stage. This incursion began in the region of the eastern Carpathian and Silesian gates and spread westward due to the development of a tectonically controlled intracratonic basin. The tectonic origin of this basin made it susceptible to tsunamis and submarine earthquakes, which constituted very dangerous hazards for coastal terrestrial and even marine reptiles. The shallow sea that spread across the Germanic Basin produced extensive tidal flats that at times formed extensive inter-peninsular bridges between the Rhenish and Bohemian Massifs. The presence of these inter-peninsular bridges explains the observed distribution and movement of reptiles along coastal Europe and the northern Tethys Seaway during the Middle Triassic epoch. Two small reptiles, probably Macrocnemus and Hescherleria, left millions of tracks and trackways known as Rhynchosauroides and Procolophonichnium in the Middle Triassic coastal intertidal zone. The great abundance of their tracks indicates that their trackmakers Macrocnemus and Hescherleria were permanent inhabitants of this environment. In sharp contrast, tracks of other large terrestrial reptiles are quite rare along the coastal margins of the Germanic Basin, for example the recently discovered archaeosaur tracks and trackways referable to Isochirotherium, which most probably were made by the carnivore Ticinosuchus. Smaller medium-sized predatory thecodont reptiles

  12. Structural, metamorphic and geochronological insights on the Variscan evolution of the Alpine basement in the Belledonne Massif (France)

    Science.gov (United States)

    Fréville, Kévin; Trap, Pierre; Faure, Michel; Melleton, Jérémie; Li, Xian-Hua; Lin, Wei; Blein, Olivier; Bruguier, Olivier; Poujol, Marc

    2018-02-01

    A structural and petrochronological study was carried out in the southern part of the Belledonne crystalline massif. A first tectonometamorphic event, Dx, corresponds to the eastward thrusting of the Chamrousse ophiolitic complex characterized by a low-temperature-moderate-pressure metamorphism reaching 0.535 ± 0.045 GPa and 427.5 ± 17.5 °C. A subsequent D1 deformation is defined by a penetrative S1 foliation that mostly dips toward the west and displays an E-W- to NE-SW-trending mineral and stretching lineation L1. D1 is associated with a top-to-the east shearing and is responsible for the crustal thickening accommodated by the eastward nappe stacking and the emplacement of the Chamrousse ophiolitic complex upon the Rioupéroux-Livet unit. This event is characterized by an amphibolite facies metamorphism (0.58 GPa ± 0.06; 608 ± 14 °C) that attains partial melting at the base of the nappe pile (0.78 ± 0.07 GPa; 680.5 ± 11.5 °C). LA-ICP-MS U-Pb dating of monazite grains from the mica schists of the Rioupéroux-Livet unit constrain the age of D1 to 337 ± 7 Ma. The D2 tectono-metamorphic event is characterized by NE-SW trending, upright to NE-verging synfolial folding. Folding associated with D2 is pervasively developed in all lithotectonic units with the development of a steeply-dipping S2 foliation. In particular, D2 involves the uppermost weakly metamorphosed Taillefer unit. LA-ICP-MS U-Pb dating performed on detrital zircon grains shows that the Taillefer conglomerates was deposited during the Visean. A zircon SIMS U-Pb age of 352 ± 1 Ma from a plagioglase-rich leucocratic sill of the Rioupéroux-Livet unit is interpreted as the age of magmatic emplacement. Our results suggest that the D2 event took place between 330 Ma and 310 Ma. We propose a new interpretation of the tectonometamorphic evolution of the southern part of the Belledonne massif, focusing on the Middle Carboniferous stages of the Variscan orogeny.

  13. Mapping the Geothermal System Using AMT and MT in the Mapamyum (QP Field, Lake Manasarovar, Southwestern Tibet

    Directory of Open Access Journals (Sweden)

    Lanfang He

    2016-10-01

    Full Text Available Southwestern Tibet plays a crucial role in the protection of the ecological environment and biodiversity of Southern Asia but lacks energy in terms of both power and fuel. The widely distributed geothermal resources in this region could be considered as potential alternative sources of power and heat. However, most of the known geothermal fields in Southwestern Tibet are poorly prospected and currently almost no geothermal energy is exploited. Here we present a case study mapping the Mapamyum (QP geothermal field of Southwestern Tibet using audio magnetotellurics (AMT and magnetotellurics (MT methods. AMT in the frequency range 11.5–11,500 Hz was used to map the upper part of this geothermal reservoir to a depth of 1000 m, and MT in the frequency range 0.001–320 Hz was used to map the heat source, thermal fluid path, and lower part of the geothermal reservoir to a depth greater than 1000 m. Data from 1300 MT and 680 AMT stations were acquired around the geothermal field. Bostick conversion with electromagnetic array profiling (EMAP filtering and nonlinear conjugate gradient inversion (NLCGI was used for data inversion. The AMT and MT results presented here elucidate the geoelectric structure of the QP geothermal field, and provide a background for understanding the reservoir, the thermal fluid path, and the heat source of the geothermal system. We identified a low resistivity anomaly characterized by resistivity in the range of 1–8 Ω∙m at a depth greater than 7 km. This feature was interpreted as a potential reflection of the partially melted magma in the upper crust, which might correlate to mantle upwelling along the Karakorum fault. It is likely that the magma is the heat source of the QP geothermal system, and potentially provides new geophysical evidence to understand the occurrence of the partially melted magmas in the upper crust in Southwestern Tibet.

  14. The effectiveness of water-treatment systems for arsenic used in 11 homes in Southwestern and Central Ohio, 2013

    Science.gov (United States)

    Thomas, Mary Ann; Ekberg, Mike

    2016-02-23

    In 2013, the U.S. Geological Survey and the Miami Conservancy District investigated the effectiveness of methods used to remove arsenic from drinking water at 11 homes in southwestern and central Ohio. The untreated (raw) ground-water had arsenic concentrations of 7.7–382 micrograms per liter (µg/L), and the median concentration was 30 µg/L. The pH was neutral to slightly alkaline, and redox conditions were strongly reducing, as indicated by high concentrations of iron. The predominant arsenic species was arsenite (As3+), which is difficult to treat because it exists in water as an uncharged compound (H3AsO3).The water-treatment systems included (1) seven single-tap reverse-osmosis systems, (2) two whole-house oxidation/filtration systems, and (3) two systems that included wholehouse anion exchange and single-tap reverse osmosis. All but one system included pretreatment by a water softener, and two systems included preoxidation to convert arsenite (As3+) to arsenate (As5+) before treatment by anion exchange.None of the treatment systems removed all of the arsenic from the drinking water. About one-half of the systems decreased the arsenic concentration to less than the maximum contamination level of 10 µg/L. The effectiveness of the systems varied widely; the percentage of arsenic removed ranged from 2 to 90 percent, and the median was 65 percent.At some sites, the low effectiveness of arsenic removal may have been related to system maintenance and(or) operation issues. At two sites, homeowners acknowledged that the treatment systems had not been maintained for several years. At two other sites, the treatment systems were being maintained, but the water-quality data indicated that one of the components was not working, unbeknownst to the homeowner. EPA research at a small number of sites in Ohio indicated that operation and maintenance of some arsenic-treatment systems was not always simple.Another factor that affected system effectiveness was the quality of

  15. Reproductive and population parameters of spiny dogfish Squalus acanthias in the south-western Atlantic Ocean.

    Science.gov (United States)

    Colonello, J H; Cortés, F; Belleggia, M; Massa, A M

    2016-05-01

    The objective of this study was to estimate reproductive and population parameters of the spiny dogfish Squalus acanthias for the south-western Atlantic Ocean. In total, 2714 specimens (1616 males and 1098 females) were collected from surveys carried out using research vessels. Males ranged from 225 to 861 mm total length (LT ) and females from 235 to 925 mm LT . The size at maturity of females (651 mm) was significantly greater than that of males (565 mm). The maximum proportion of mature individuals (Pmax ) of the gestation ogive was 156 mm). The temporal and spatial co-occurrence of non-gravid adult females at different stages of ovarian development, as well as gravid females at all embryonic development stages would indicate that the female reproductive cycle in the south-western Atlantic Ocean is asynchronous. The results indicate that S. acanthias is susceptible to fishing pressure on account of its length at maturity, extended reproductive cycles and low fecundity. © 2016 The Fisheries Society of the British Isles.

  16. Comparative phytosociological investigation of subalpine alder thickets in southwestern Alaska and the North Pacific

    Science.gov (United States)

    Talbot, Stephen S.; Talbot, Sandra L.; Daniëls, F. J. A.

    2005-01-01

    We present the first vegetation analysis of subalpine alder (Alnus viridis) thickets in southwestern Alaska. The data are primarily from mesic, hilly and mountainous sites ranging from the westernmost tip of the Alaska Peninsula to the northern Kenai Peninsula, spanning 1,000 km on an E–W gradient and 700 km on a N–S gradient. 127 relevés from 18 sites represent the range of structural and compositional variation in the matrix of vegetation and landform diversity. Data were analyzed by multivariate and traditional Braun-Blanquet methods. One association is distinguished, Sambuco racemosi-Alnetum viridis ass. nov. with three new subassociations, oplopanacetosum horridi, typicum, and rubetosum spectabilis with the latter subdivided into four variants. These phytocoena are well-differentiated, although they form a syntaxonomical continuum. The composition and structure of these communities are described and interpreted in relation to complex environmental factors; these are analyzed using Jancey's ranking on F-values. Community composition is primarily related to elevation, longitude, soil moisture, and latitude. Phytogeographic comparison of southwestern Alaska alder communities with those elsewhere in the North Pacific suggests a close floristic relationship to those of southcentral, southeastern Alaska and coastal British Columbia, Canada. All these communities belong to the same association, while those of the eastern and southern parts of the Kamchatka Peninsula, Russia belong to a different association. Syntaxonomy of the 4 major communities is discussed. Within the Northern Hemisphere, vascular plant species of southwestern Alaska alder thickets primarily occur in East Asia and North America, 36 %; while 26 % are circumpolar, and 22 % are restricted to North America. From a latitudinal perspective, the distribution of vascular plant species within these alder thickets peaks in the high-subarctic, low-subarctic, and temperate latitudinal zones, with low

  17. Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Rodolfo Sosa, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Humberto Bravo, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico)], E-mail: hbravo@servidor.unam.mx; Violeta Mugica, A. [Universidad Autonoma Metropolitana, Azcapotzalco, D.F. (Mexico); Pablo Sanchez, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Emma Bueno, L. [Centro Nacional de Investigacion y Capacitacion Ambiental, Instituto Nacional de Ecologia (Mexico); Krupa, Sagar [Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 (United States)

    2009-03-15

    Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City.

  18. Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

    International Nuclear Information System (INIS)

    Rodolfo Sosa, E.; Humberto Bravo, A.; Violeta Mugica, A.; Pablo Sanchez, A.; Emma Bueno, L.; Krupa, Sagar

    2009-01-01

    Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City

  19. Cutaneous adornment in the Yoruba of south-western Nigeria - past and present.

    Science.gov (United States)

    George, Adekunle O; Ogunbiyi, Adebola O; Daramola, Olaniyi O M

    2006-01-01

    The traditional practice of cutaneous adornment is rich and vast amongst the Yoruba in the south-western part of Nigeria. There are varieties of traditionally made products, such as oils, soaps, fragrances, and beads, that have been employed over the years to enhance body beauty. This rich cultural heritage, however, has more or less given way to the values of Western culture, together with the disadvantages of the latter, manifesting as sequelae on the skin.

  20. Hibernacula selection by Townsend's big-eared bat in Southwestern Colorado

    Science.gov (United States)

    Hayes, Mark A.; Schorr, Robert A.; Navo, Kirk W.

    2011-01-01

    In western United States, both mine reclamations and renewed mining at previously abandoned mines have increased substantially in the last decade. This increased activity may adversely impact bats that use these mines for roosting. Townsend's big-eared bat (Corynorhinus townsendii) is a species of conservation concern that may be impacted by ongoing mine reclamation and renewed mineral extraction. To help inform wildlife management decisions related to bat use of abandoned mine sites, we used logistic regression, Akaike's information criterion, and multi-model inference to investigate hibernacula use by Townsend's big-eared bats using 9 years of data from surveys inside abandoned mines in southwestern Colorado. Townsend's big-eared bats were found in 38 of 133 mines surveyed (29%), and occupied mines averaged 2.6 individuals per mine. The model explaining the most variability in our data included number of openings and portal temperature at abandoned mines. In southwestern Colorado, we found that abandoned mine sites with more than one opening and portal temperatures near 0°C were more likely to contain hibernating Townsend's big-eared bats. However, mines with only one opening and portal temperatures of ≥10°C were occasionally occupied by Townsend's big-eared bat. Understanding mine use by Townsend's big-eared bat can help guide decisions regarding allocation of resources and placement of bat-compatible closures at mine sites scheduled for reclamation. When feasible we believe that surveys should be conducted inside all abandoned mines in a reclamation project at least once during winter prior to making closure and reclamation recommendations.