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Sample records for basin basement structures

  1. Integrated geophysical investigations of linkages between Precambrian basement and sedimentary structures in the Ucayali basin, Peru; Fort Worth basin, Texas; and Osage County, Oklahoma

    Science.gov (United States)

    Elebiju, Olubunmi Olumide

    I conducted integrated geophysical studies within the Fort Worth basin, Texas; Osage County, Oklahoma, and the Ucayali basin, Peru. My studies are directed at understanding the relationships or links between Precambrian basement structures and sedimentary structures using these three areas as case studies. Links between basement structure, hydrocarbon reservoirs, and sedimentary sequences are not a new concept. Such relationships have been documented in the Paradox, Hardeman, Anadarko, Arkoma, Ardmore and Williston basins among others. Structures such as fault zones that can influence the formation of sedimentary basins and mineral deposits are often formed by intraplate tectonism. In order to compare the relationship between the Precambrian basement structures and sedimentary structures, I analyzed series of derivative and filtered maps of aeromagnetic and gravity data, which enhance basement structures, that were integrated with seismic data and seismic attribute data that enhance structures within the sedimentary sections. Other information such as well data and geologic information etc were also integrated. This integrated workflow facilitates the comparison of the links or relationships between the two structures. The results of the Fort Worth basin are presented in Chapter 3. The results of this integrated study show that the sedimentary structures within the study area are mainly related to basement structures because these structures are aligned parallel to anomalies identified on the high-resolution aeromagnetic (HRAM) data. The northeast-southwest and northwest-southeast orientations of sedimentary features are consistently parallel with Precambrian structural fabrics that are associated with structures such as the northeast trending Ouachita orogenic belt and the northwest trending Muenster Arch, which reactivated a late Cambrian/Late Precambrian faults. The knowledge gained in this study will impact oil and gas exploration and development within the

  2. Structural control of the basement in the central portion of the Santos Basin-Brazil; Controle estrutural do embasamento na porcao central da Bacia de Santos

    Energy Technology Data Exchange (ETDEWEB)

    Izeli, Maira G.B.; Morales, Norberto; Souza, Iata A. de [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas

    2008-07-01

    New discoveries of oil in deep water and ultra-deep water in Santos Basin suggest that it needs to be studied to better understanding of basement structures and their role in the basin control and configuration. This study characterizes the main tectonic structures of a portion at the central area of this basin, looking for their relation to the geological basement framework. The study is based on the integration of the geological and geophysical data from subsurface (offshore) and surface of the adjacent continent. These analyses include the continental structures that continue in direction of this basin (Guapiara Lineament and Ponta Grossa Arc), checking their possible influence on the basin evolution and deformation. To achieve the proposed goals, the Precambrian basement lineaments were extracted from the offshore area using remote sensing, as result was obtained strong NW-SE structural trend. According to the interpretation of seismic sections, it is possible to observe that this portion of the basin presents main NE-SW structural trend, and most of the structures are typical of passive margin and halokintics process. It is possible to see that some recognized faults in the rift deposits may be coinciding with the main continental guidelines which are projected into the basin. (author)

  3. Basement configuration of KG offshore basin from magnetic anomalies

    Indian Academy of Sciences (India)

    Marine magnetic anomalies along three representative profiles falling between shelf break and continent–ocean boundary in the offshore Krishna–Godavari basin were quantitatively interpreted for understandingthe nature and structure of the magnetic basement using inversion technique. The interpretation of ...

  4. Influence of inherited structures on the growth of basement-cored ranges, basin inversion and foreland basin development in the Central Andes, from apatite fission-track and apatite Helium thermochronology.

    Science.gov (United States)

    Zapata, S.; Sobel, E. R.; Del Papa, C.; Jelinek, A. R.; Muruaga, C.

    2017-12-01

    The Central Andes in NW of Argentina is part of a long-lived subduction zone, active since the Paleozoic. This region experienced several tectonic cycles; each of which created an unique set of structures and may have reactivated preexisting structures. These inherited structures may exert a first-order control over the different foreland deformational styles observed along the strike in the Central Andes. Our study area is located between 26°S and 28°S on the transition between the broken foreland (Santa Barbara system), which expresses a combination of thin-skin and thick-skin styles, and the Sierras Pampeanas, which is deform in a thick-skin style. The Cumbres Calchaquies range and the associated Choromoro Basin are located in the northern part of the study area, and are the southern expression of the Santa Barbara system. Published thermochronology data suggest that the rocks from the basement experienced Late Cretaceous and Late Miocene exhumation; the associated sedimentary rocks within the Choromoro basin experienced Paleogene and Late Miocene deformational phases. In contrast, the Sierra Aconquija range, located immediately south on the transition to the Sierras Pampeanas (thick skin) foreland basin, exhibit larger amounts of Miocene exhumation and lack of Cretaceous exhumation; the associated sedimentary rocks from the Tucuman basin have not been deformed since the Cretaceous. Our goal is to understand the evolution of the structural blocks and the structures responsible for the along strike changes in foreland basin deformational styles and their relation with inherited structures from previous tectonic cycles. We are obtaining new apatite U-Th/He and fission track data to reconstruct the thermal history of the basement, accompanied by U-Pb geochronology and stratigraphy to constrain the evolution of the associated sedimentary basins. Preliminary results combined with published data suggest that inherited structures within the study area have evolved

  5. Basement geology of Taranaki and Wanganui basins, New Zealand

    International Nuclear Information System (INIS)

    Mortimer, N.; Tulloch, A.J.; Ireland, T.R.

    1997-01-01

    We present a revised interpretation of the basement geology beneath Late Cretaceous to Cenozoic Taranaki and Wanganui basins of central New Zealand, based on new petrographic, geochemical, and geochronological data from 30 oil exploration wells. Recently published structural and magnetic interpretations of the area assist in the interpolation and extrapolation of geological boundaries. Torlesse and Waipapa terranes have been identified in Wanganui Basin, and Murihiku Terrane in eastern Taranaki Basin, but Maitai and Brook Street terrane rocks have not been recognised. Separation Point Suite, Karamea Suite, and Median Tectonic Zone igneous rocks are all identified on the basis of characteristic petrography, geochemistry, and/or age. SHRIMP U-Pb zircon measurements on igneous samples from western Taranaki wells do not give precise ages but do provide useful constraints: Motueka-1 granite is latest Devonian - earliest Carboniferous; Tangaroa-1 and Toropuihi-1 are Carboniferous; and Surville-1 is Cretaceous (cf. Separation Point Suite). Our interpretation of sub-basin geology is compatible with previously observed onland relationships in the North and South Islands. (author). 47 refs., 6 figs

  6. A low-angle normal fault and basement structures within the Enping Sag, Pearl River Mouth Basin: Insights into late Mesozoic to early Cenozoic tectonic evolution of the South China Sea area

    Science.gov (United States)

    Ye, Qing; Mei, Lianfu; Shi, Hesheng; Shu, Yu; Camanni, Giovanni; Wu, Jing

    2018-04-01

    The basement structure of the Cenozoic Enping Sag, within the Pearl River Mouth Basin on the northern margin of South China Sea, is revealed by borehole-constrained high-quality 3D seismic reflection data. Such data suggest that the Enping Sag is bounded in the north by a low-angle normal fault. We interpret this low-angle normal fault to have developed as the result of the reactivation of a pre-existing thrust fault part of a pre-Cenozoic thrust system. This is demonstrated by the selective reactivation of the pre-existing thrust and by diffuse contractional deformation recognized from the accurate analysis of basement reflections. Another significant result of this study is the finding of some residual rift basins within the basement of the Enping Sag. Both the thrust system and the residual basins are interpreted to have developed after the emplacement of continental margin arc-related granitoids (J3-K1) that define the basement within the study area. Furthermore, seismic sections show that the pre-existing residual rift basins are offset by the main thrust fault and they are both truncated by the Tg unconformity. These structural relationships, interpreted in the frame of previous studies, help us to reconstruct a six-event structural evolution model for the Enping Sag from the late Mesozoic to the early Cenozoic. In particular, we interpret the residual rift basins to have formed as the result of back-arc extension due to the slab roll-back of the Paleo-Pacific Plate subduction in the early K2. The thrust system has recorded a compressional event in the late K2 that followed the back-arc extension in the SCS area. The mechanism of this compressional event is still to be clarified, and might be related to continuous subduction of the Paleo-Pacific Plate or to the continent-continent collision between a micro-continental block and the South China margin.

  7. Basement blocks and basin inversion structures mapped using reprocessed Gulfrex 2D seismic data, Caribbean-South American oblique collisional zone

    Science.gov (United States)

    Escalona, A.; Sena, A.; Mann, P.

    2003-12-01

    We have reprocessed and reinterpreted more than 10,000 km of "Gulfrex" multi-channel 2D seismic reflection lines collected by Gulf Oil Corporation in 1972 along the northern margin of South America (offshore Venezuela and Trinidad). These digital data were donated to the University of Texas Institute for Geophysics and represent the largest single, digital reflection survey of the region. Reprocessing of these data included: format correction, filtering, post-stack multiple suppression, and fk migration. Reprocessed data were loaded and interpreted on a workstation. The data straddle a 2,000,000 km2 zone of Paleocene-Recent, time-transgressive, oblique collision between the Caribbean arc system and the passive continental margin of northern South America. Free-air, satellite gravity data shows the remarkable 1000-km-scale continuity of four basement ridges between the uncollided part of the Caribbean arc system (NS-trending Lesser Antilles arc) and the EW-trending collisional area north of Venezuela. The basement ridges involved in the Venezuelan collisional zone include: 1) Aruba-Bonaire-Curacao ridge that can be traced as a continuous feature to the Aves ridge remnant arc of the Lesser Antilles; 2) the partially inverted Blanquilla-Bonaire basin that can be traced into the Grenada back-arc basin; 3) Margarita-Los Testigos platform that can be traced to the Lesser Antilles volcanic arc; and 4) foreland basins and fold-thrust belts of eastern Venezuela (Serrania del Interior and Maturin basin) that can be traced to the Tobago forearc basin and Barbados accretionary prism. Gulfrex data document the progressive change of basinal fault systems from NS-striking normal faults formed in extensional, Lesser Antilles intra-arc settings to rotated and inverted, NE and EW-striking normal faults deformed in the collisional area north of Venezuela. Age of initial shortening of basinal areas and inversion of normal faults setting does not follow the simple, expected pattern of

  8. Discussion on the basement topography and its relation with the uranium mineralization in Xiangshan basin

    International Nuclear Information System (INIS)

    Long Qihua; Liu Qingcheng

    2002-01-01

    The depth of the basement and the relation between the basement relief shape and uranium mineralization are discussed by forward and inverse computation for large-scale gravity data in Xiangshan basin. The difference of basement topography result in the inhomogeneous distribution of uranium mineralization. The margin of the basement upheaval section and the variation place of basement topography are the favorable place for uranium mineralization. It's helpful to prospect deep and blind uranium deposit in Xiangshan basin

  9. Fault assessment for basement reservoir compartmentalization: Case study at Northeast Betara gas field, South Sumatra Basin

    Science.gov (United States)

    Risyad, M.; Suta, I. N.; Haris, A.

    2017-07-01

    Northeast Betara field is situated on the northern part of prolific South Sumatra Basin. It has produced gas from Lower Talang Akar Formation sandstone and over 90 wells have been drilled. A 3D seismic data was acquired in 2000 and reprocessed in 2012 to enhance the subsurface image. In 2013 an exploratory well NEB Base-1 was drilled and made gas and condensate discovery from the subsequent pre-tertiary basement which is confirmed as granite. The well proved fractured basement reservoir play on paleo high of the structure. The absence of full-diameter conventional core prompts well logs and seismic data analysis by using a workstation. Main methods for fracture prediction have been seismic attributes extraction and structural geology studies of basement provided by image logs on a few exploration wells. Ant tracking attribute is widely employed to image seismic event discontinuities due to extensive faults which generated the natural fractures. Delineations well NEB Base-2 was drilled on second paleo high and unfortunately, it did not find any gas indication from pre-tertiary basement target. Seismic structural interpretation and seismic attributes are conducted to image distribution of event discontinuities related to faults or fracture. We found that compartmentalization on basement involved old faults and both paleo high have undergone different structural history and stress character which resulted in separated fractures distribution.

  10. Formation evaluation of fractured basement, Cambay Basin, India

    International Nuclear Information System (INIS)

    Gupta, Saurabh Datta; Farooqui, M Y; Chatterjee, Rima

    2012-01-01

    Unconventional reservoirs such as fractured basalts, shale gas and tight sand are currently playing an important role in producing a significant amount of hydrocarbon. The Deccan Trap basaltic rocks form the basement of the Cambay Basin, India, and hold commercially producible hydrocarbon. In this study two wells drilled through fractured basalts are chosen for evaluating the lithology, porosity and oil saturation of the reservoir sections. Well logs, such as gamma ray, high resolution resistivity, litho density, compensated neutron and elemental capture spectroscopy, have been used in cross-plotting techniques for lithology and mineral identification. Formation micro imagery log data have been analysed to quantify the fractures and porosity in the fractured reservoirs for a well in the south Ahmedabad block of the Cambay Basin. The results of the analysis of two wells are presented and discussed and they are found to be in good agreement with geological and production data. (paper)

  11. Structural and Geophysical Characterization of Oklahoma Basement

    Science.gov (United States)

    Morgan, C.; Johnston, C. S.; Carpenter, B. M.; Reches, Z.

    2017-12-01

    Oklahoma has experienced a large increase in seismicity since 2009 that has been attributed to wastewater injection. Most earthquakes, including four M5+ earthquakes, nucleated at depths > 4 km, well within the pre-Cambrian crystalline basement, even though wastewater injection occurred almost exclusively in the sedimentary sequence above. To better understand the structural characteristics of the rhyolite and granite that makeup the midcontinent basement, we analyzed a 150 m long core recovered from a basement borehole (Shads 4) in Rogers County, NE Oklahoma. The analysis of the fracture network in the rhyolite core included measurements of fracture inclination, aperture, and density, the examination fracture surface features and fill minerology, as well as x-ray diffraction analysis of secondary mineralization. We also analyzed the highly fractured and faulted segments of the core with a portable gamma-ray detector, magnetometer, and rebound hammer. The preliminary analysis of the fractures within the rhyolite core showed: (1) Fracture density increasing with depth by a factor of 10, from 4 fractures/10m in the upper core segment to 40 fracture/10m at 150 m deeper. (2) The fractures are primarily sub-vertical, inclined 10-20° from the axis of the vertical core. (3) The secondary mineralization is dominated by calcite and epidote. (4) Fracture aperture ranges from 0.35 to 2.35mm based on the thickness of secondary filling. (5) About 8% of the examined fractures display slickenside striations. (6) Increases of elasticity (by rebound hammer) and gamma-ray emissions are systematically correlated with a decrease in magnetic susceptibility in core segments of high fracture density and/or faulting; this observation suggests diagenetic fracture re-mineralization.

  12. Tectonic inheritage from adjacent basement, north of the Campos Basin; Heranca tectonica no embasamento adjacente no norte da Bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Ferroni, Felipe R. [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil); Castro, Joel C. de [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas. Dept. de Geologia Aplicada; Souza, Iata A. de; Castro, Joel C. de [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas

    2008-07-01

    The evolution of the Atlantic Brazilian basins is a target of researches since the firth discovery of oil deposits. With the advance of the geophysical methods the understanding of the structures in depth became possible. The objective of this paper is to determine if the adjacent basement in the north of Campos Basin has significant influence in the identification of areas that can contain hydrocarbons. Therefore, lineaments had been extracted with SRTM images of continental basement and the main alignment was correlated with gravimetric anomalies map and seismic data. Eight levels on seismic data had been interpreted (basement, top rift, shallow water Albian, Albian, mid-Oligocene and mid-Miocene). In all levels were identified a fault normal system, which cut sediments since basement until the Recent. The main direction of the basement is NE-SW, and the alignments formed for basin basement faults coincide with this direction, what indicates that the system is active and also genetically related. (author)

  13. Structural analysis of a fractured basement reservoir, central Yemen

    Science.gov (United States)

    Veeningen, Resi; Rice, Hugh; Schneider, Dave; Grasemann, Bernhard; Decker, Kurt

    2013-04-01

    The Pan-African Arabian-Nubian Shield (ANS), within which Yemen lies, formed as a result of Neoproterozoic collisional events between c. 870-550 Ma. Several subsequent phases of extension occurred, from the Mesozoic (due to the breakup of Gondwana) to the Recent (forming the Gulf of Aden and the Red Sea). These resulted in the formation of numerous horst- and-graben structures and the development of fractured basement reservoirs in the southeast part of the ANS. Two drill cores from the Mesozoic Marib-Shabwa Basin, central Yemen, penetrated the upper part of the Pan-African basement. The cores show both a lithological and structural inhomogeneity, with variations in extension-related deformation structures such as dilatational breccias, open fractures and closed veins. At least three deformation events have been recognized: D1) Ductile to brittle NW-SE directed faulting during cooling of a granitic pluton. U-Pb zircon ages revealed an upper age limit for granite emplacement at 627±3.5 Ma. As these structures show evidence for ductile deformation, this event must have occurred during the Ediacaran, shortly after intrusion, since Rb/Sr and (U-Th)/He analyses show that subsequent re-heating of the basement did not take place. D2) The development of shallow dipping, NNE-SSW striking extensional faults that formed during the Upper Jurassic, simultaneously with the formation of the Marib-Shabwa Basin. These fractures are regularly cross-cut by D3. D3) Steeply dipping NNE-SSW to ENE-WSW veins that are consistent with the orientation of the opening of the Gulf of Aden. These faults are the youngest structures recognized. The formation of ductile to brittle faults in the granite (D1) resulted in a hydrothermally altered zone ca. 30 cm wide replacing (mainly) plagioclase with predominantly chlorite, as well as kaolinite and heavy element minerals such as pyrite. The alteration- induced porosity has an average value of 20%, indicating that the altered zone is potentially a

  14. Basement configuration of KG offshore basin from magnetic anomalies

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, V.; Swamy, K.V.; Raj, N.

    basement is faulted along the NW-SE direction with the upthrown side lying to the north of the anomaly trend of this region. The coincidence of magnetizations observed through the present interpretation with that of charnockites of neighbouring EGMB...

  15. Characteristics of the crystalline basement beneath the Ordos Basin: Constraint from aeromagnetic data

    Directory of Open Access Journals (Sweden)

    Zhentao Wang

    2015-05-01

    Full Text Available Aeromagnetic anomaly zonation of the Ordos Basin and adjacent areas was obtained by processing high-precision and large-scale aeromagnetic anomalies with an approach of reduction to the pole upward continuation. Comparative study on aeromagnetic and seismic tomography suggests that aeromagnetic anomalies in this area are influenced by both the magnetic property of the rock and the burial depth of the Precambrian crystalline basement. Basement depth might be the fundamental control factor for aeromagnetic anomalies because the positive and negative anomalies on the reduction to the pole-upward-continuation anomaly maps roughly coincide with the uplifts and depressions of the crystalline basement in the basin. The results, together with the latest understanding of basement faults, SHRIMP U-Pb zircon dating of metamorphic rock and granite, drilling data, detrital zircon ages, and gravity data interpretation, suggest that the Ordos block is not an entirety of Archean.

  16. Rift architecture and evolution: The Sirt Basin, Libya: The influence of basement fabrics and oblique tectonics

    Science.gov (United States)

    Abdunaser, K. M.; McCaffrey, K. J. W.

    2014-12-01

    The Cretaceous-Tertiary northwest-trending Sirt Basin system, Libya, is a rift/sag basin formed on Pan-African to Paleozoic-aged basement of North Africa. In this study, we investigate the rift-basin architecture and tectonic framework of the western Sirt Basin. Using remote sensed data, supported by borehole data from about 300 deep wells and surface geologic maps, we constructed geological cross sections and surface geology maps. Indication of the relative timing of structures and movement along faults has been determined where possible. Direction statistics for all the interpreted linear features acquired in the study area were calculated and given as a total distribution and then the totals are broken down by the major basin elements of the area. Hundreds of lineaments were recognized. Their lengths, range between a hundred meters up to hundreds of kilometers and the longest of the dominant trends are between N35W-N55W and between N55E-N65E which coincides with Sirt Basin structures. The produced rose diagrams reveal that the majority of the surface linear features in the region have four preferred orientations: N40-50W in the Zallah Trough, N45-55W in the Dur al Abd Trough, N35-55W in the Az Zahrah-Al Hufrah Platform, and in contrast in the Waddan Uplift a N55-65E trend. We recognize six lithostratigraphic sequences (phases) in the area's stratigraphic framework. A Pre-graben (Pre-rift) initiation stage involved the Pre-Cretaceous sediments formed before the main Sirt Basin subsidence. Then followed a Cretaceous to Eocene graben-fill stage that can divided into four structurally-active and structurally-inactive periods, and finally a terminal continental siliciclastics-rich package representing the post-rift stage of the development in post-Eocene time. In general five major fault systems dissect and divide the study area into geomorphological elevated blocks and depressions. Most of the oil fields present in the study area are associated with structural hinge

  17. Basement configuration of KG offshore basin from magnetic anomalies

    Indian Academy of Sciences (India)

    extends up to COB in the offshore K–G basin. 1. Introduction. The Eastern Continental Margin of India (ECMI) has been a seat of vigorous geophysical exploration ..... Precambrian Gondwanaland; J. Geol. 97 646–648. Kumar S P 1983 Geology and hydrocarbon prospects of. Krishna–Godavari and Cauvery basins; Petrol.

  18. Two-stage formation model of the Junggar basin basement: Constraints to the growth style of Central Asian Orogenic Belt

    Science.gov (United States)

    He, Dengfa

    2016-04-01

    Junggar Basin is located in the central part of the Central Asian Orogenic Belt (CAOB). Its basement nature is a highly controversial scientific topic, involving the basic style and processes of crustal growth. Some researchers considered the basement of the Junggar Basin as a Precambrian continental crust, which is not consistent with the petrological compositions of the adjacent orogenic belts and the crust isotopic compositions revealed by the volcanic rocks in the basin. Others, on the contrary, proposed an oceanic crust basement model that does not match with the crustal thickness and geophysical characteristics of the Junggar area. Additionally, there are several viewponits, such as the duplex basement with the underlying Precambrian crystalline rocks and the overlying pre-Carboniferous folded basement, and the collaged basement by the Precambrian micro-continent block in the central part and the Hercynian accretionary folded belts circling it. Anyway, it is necessary to explain the property of basement rock, its strong inhomogeneous compositions as well as the geophysical features. In this paper, based on the borehole data from more than 300 industry wells drilled into the Carboniferous System, together with the high-resolution gravity and magnetic data (in a scale of 1:50,000), we made a detailed analysis of the basement structure, formation timing and processes and its later evolution on a basis of core geochemical and isotopic analysis. Firstly, we defined the Mahu Pre-Cambrian micro-continental block in the juvenile crust of Junggar Basin according to the Hf isotopic analysis of the Carboniferous volcanic rocks. Secondly, the results of the tectonic setting and basin analysis suggest that the Junggar area incorporates three approximately E-W trending island arc belts (from north to south: Yemaquan- Wulungu-Chingiz, Jiangjunmiao-Luliang-Darbut and Zhongguai-Mosuowan- Baijiahai-Qitai island arcs respectively) and intervened three approximately E-W trending

  19. Basement structures over Rio Grande Rise from gravity inversion

    Science.gov (United States)

    Constantino, Renata; Hackspacker, Peter Christian; Anderson de Souza, Iata; Sousa Lima Costa, Iago

    2017-04-01

    In this study, we show that from satellite-derived gravity field, bathymetry and sediment thicknesses, it is possible to give a 3-D model of the basement over oceanic areas, and for this purpose, we have chosen the Rio Grande Rise, in South Atlantic Ocean, to build a gravity-equivalent basement topography. The advantages of the method applied in this study are manifold: does not depend directly on reflection seismic data; can be applied quickly and with fewer costs for acquiring and interpreting the data; and as the main result, presents the physical surface below the sedimentary layer, which may be different from the acoustic basement. We evaluated the gravity effect of the sediments using the global sediment thickness model of NOAA, fitting a sediment compaction model to observed density values from Deep Sea Drilling Program (DSDP) reports. The Global Relief Model ETOPO1 and constraining data from seismic interpretation on crustal thickness are integrated in the gravity inversion procedure. The modeled Moho depth values vary between 6 to 27 km over the area, being thicker under the Rio Grande Rise and also in the direction of São Paulo Plateau. The inversion for the gravity-equivalent basement topography is applied for a gravity residual data, which is free from the gravity effect of sediments and from the gravity effect of the estimated Moho interface. A description of the basement depth over Rio Grande Rise area is unprecedented in the literature, however, our results could be compared to in situ data, provided by DSDP, and a small difference of only 9 m between our basement depth and leg 516 F was found. Our model shows a rift crossing the entire Rio Grande Rise deeper than previously presented in literature, with depths up to 5 km in the East Rio Grande Rise (ERGR) and deeper in the West Rio Grande Rise (WRGR), reaching 6.4 km. We find several short-wavelengths structures not present in the bathymetry data. Seamounts, guyots and fracture zones are much more

  20. A fall-out shelter or basement structure

    International Nuclear Information System (INIS)

    Blatchford, J.M.A.

    1982-01-01

    A strong structure of precast concrete for use as a fallout shelter, tank, basement structure, blast-proof garage is described. It consists of several upright, concrete wall elements, including L-shaped sections, and at least one concrete roof element. The concrete elements are preferably encased in, and may also be supported on, a concrete surround which is formed in situ and which may be secured to the elements by projecting links. The structure may be assembled as an underground or above-ground building. This invention provides a strong structure of quite large span which is relatively simple in construction and can be rapidly assembled. (U.K.)

  1. Heat flow in Indian Gondwana basins and heat production of their basement rocks

    Energy Technology Data Exchange (ETDEWEB)

    Rao, G.V.; Rao, R.U.M.

    1983-01-01

    Temperatures have been measured in eight boreholes (ranging from 260 to 800 m in depth) in five Gondwana basins of the Damodar and Son valleys. With the aid of about 250 thermal conductivity determinations on core samples from these holes, heat flow has been evaluated. Measurements of radioactive heat generation have been made on samples of Precambrian gneisses constituting the basement for the Sonhat (Son valley) and Chintalapudi (Godavari valley) basins. Heat-flow values from all of the Damodar valley basins are within the narrow range of 69-79 mW/m exp(2). The value from the Sonhat basin (107 mW/m exp(2)) is significantly higher. The generally high heat flows observed in Gondwana basins of India cannot be attributed to the known tectonism or igneous activity associated with these basins. The plots of heat flow vs. heat generation for three Gondwana basins (Jharia, Sonhat and Chintalapudi) are on the same line as those of three regions in the exposed Precambrian crystalline terrains in the northern part of the Indian shield. This indicates that the crust under exposed regions of the Precambrian crystalline rocks as well as the Gondwana basins, form an integral unit as far as the present-day geothermal character is concerned. (5 figs., 14 refs., 4 tables).

  2. Heat flow in Indian Gondwana basins and heat production of their basement rocks

    Science.gov (United States)

    Rao, G. V.; Rao, R. U. M.

    1983-01-01

    Temperatures have been measured in eight boreholes (ranging from 260 to 800 m in depth) in five Gondwana basins of the Damodar and Son valleys. With the aid of about 250 thermal conductivity determinations on core samples from these holes, heat flow has been evaluated. Measurements of radioactive heat generation have been made on samples of Precambrian gneisses constituting the basement for the Sonhat (Son valley) and Chintalapudi (Godavari valley) basins. Heat-flow values from all of the Damodar valley basins are within the narrow range of 69-79 mW/m 2. The value from the Sonhat basin (107 mW/m 2) is significantly higher. The generally high heat flows observed in Gondwana basins of India cannot be attributed to the known tectonism or igneous activity associated with these basins. The plots of heat flow vs. heat generation for three Gondwana basins (Jharia, Sonhat and Chintalapudi) are on the same line as those of three regions in the exposed Precambrian crystalline terrains in the northern part of the Indian shield. This indicates that the crust under exposed regions of the Precambrian crystalline rocks as well as the Gondwana basins, form an integral unit as far as the present-day geothermal character is concerned.

  3. Basement Structure and Styles of Active Tectonic Deformation in Central Interior Alaska

    Science.gov (United States)

    Dixit, N.; Hanks, C.

    2017-12-01

    Central Interior Alaska is one of the most seismically active regions in North America, exhibiting a high concentration of intraplate earthquakes approximately 700 km away from the southern Alaska subduction zone. Based on increasing seismological evidence, intraplate seismicity in the region does not appear to be uniformly distributed, but concentrated in several discrete seismic zones, including the Nenana basin and the adjacent Tanana basin. Recent seismological and neotectonics data further suggests that these seismic zones operate within a field of predominantly pure shear driven primarily by north-south crustal shortening. Although the location and magnitude of the seismic activity in both basins are well defined by a network of seismic stations in the region, the tectonic controls on intraplate earthquakes and the heterogeneous nature of Alaska's continental interior remain poorly understood. We investigated the current crustal architecture and styles of tectonic deformation of the Nenana and Tanana basins using existing geological, geophysical and geochronological datasets. The results of our study demonstrate that the basements of the basins show strong crustal heterogeneity. The Tanana basin is a relatively shallow (up to 2 km) asymmetrical foreland basin with its southern, deeper side controlled by the northern foothills of the central Alaska Range. Northeast-trending strike-slip faults within the Tanana basin are interpreted as a zone of clockwise crustal block rotation. The Nenana basin has a fundamentally different geometry; it is a deep (up to 8 km), narrow transtensional pull-apart basin that is deforming along the left-lateral Minto Fault. This study identifies two distinct modes of tectonic deformation in central Interior Alaska at present, and provides a basis for modeling the interplay between intraplate stress fields and major structural features that potentially influence the generation of intraplate earthquakes in the region.

  4. Thermochronology and geochemistry of the Pan-African basement below the Sab'atayn Basin, Yemen

    Science.gov (United States)

    Veeningen, Resi; Rice, A. Hugh N.; Schneider, David A.; Grasemann, Bernhard

    2015-02-01

    Three important lithologies occur in two drill wells from the Pan-African basement underlying the Mesozoic Sab'atayn Basin, in a previously undocumented area of the Pan-African, 83 and 90 km NE of known exposures in Yemen. Cores from well 1 include amphibolite, with basaltic to andesitic compositions, affected by crustal contamination during emplacement into a thickened crust. Deeper in the well, an unfoliated dark red monzogranite has a U-Pb zircon age of 628.8 ± 3.1 Ma and a Rb-Sr biotite cooling age of 591.6 ± 5.8 Ma (∼300 °C). Regional constraints suggest emplacement in a transitional tectonic setting with compressional terrane amalgamation followed by extensional collapse. Sm-Nd isotope analysis yields a TDM model age of 1.24 Ga with negative εNd values, suggesting the monzogranite is part of the Al Bayda island arc terrane. Cores from well 2 contains a weakly deformed, massive (unbedded) medium grey meta-arkose exhibiting essentially no geochemical signature of weathering and with an almost pure dacitic composition. This rock may have been directly derived from an (extrusive) granitoid that was emplaced prior to, or during terrane amalgamation. A (U-Th-Sm)/He zircon age of 156 ± 14 Ma constrains the time of basement cooling to ∼180 °C, synchronous with basin formation. These lithologies provide new insights in the development of the Pan-African basement of Yemen, extending our knowledge of the nearby surface geology to the subsurface.

  5. Basement structure of the United Arab Emirates derived from an analysis of regional gravity and aeromagnetic database

    Science.gov (United States)

    Ali, M. Y.; Fairhead, J. D.; Green, C. M.; Noufal, A.

    2017-08-01

    Gravity and aeromagnetic data covering the whole territory of the United Arab Emirates (UAE) have been used to evaluate both shallow and deep geological structures, in particular the depth to basement since it is not imaged by seismic data anywhere within the UAE. Thus, the aim has been to map the basement so that its structure can help to assess its control on the distribution of hydrocarbons within the UAE. Power spectrum analysis reveals gravity and magnetic signatures to have some similarities, in having two main density/susceptibility interfaces widely separated in depth such that regional-residual anomaly separation could effectively be undertaken. The upper density/susceptibility interface occurs at a depth of about 1.0 km while the deeper interface varies in depth throughout the UAE. For gravity, this deeper interface is assumed to be due to the combined effect of lateral changes in density structures within the sediments and in depth of basement while for magnetics it is assumed the sediments have negligible susceptibility and the anomalies unrelated to the volcanic/magmatic bodies result from only changes in depth to basement. The power spectrum analysis over the suspect volcanic/magmatic bodies indicates they occur at 5 km depth. The finite tilt-depth and finite local wavenumber methods were used to estimate depth to source and only depths that agree to within 10% of each other were used to generate the depth to basement map. This depth to basement map, to the west of the UAE-Oman Mountains, varies in depth from 5 km to in excess of 15 km depth and is able to structurally account for the location of the shear structures, seen in the residual magnetic data, and the location of the volcanic/magmatic centres relative to a set of elongate N-S to NE-SW trending basement highs. The majority of oilfields in the UAE are located within these basement highs. Therefore, the hydrocarbon distribution in the UAE basin appears to be controlled by the location of the

  6. Relationship of present saline fluid with paleomigration of basinal brines at the basement/sediment interface (Southeast basin – France)

    International Nuclear Information System (INIS)

    Aquilina, Luc; Dreuzy, Jean-Raynald De

    2011-01-01

    This paper investigates the isotopic composition (O, D, Sr, O SO 4 , S SO 4 , Cl, He) of a present saline fluid sample collected at the sediment/basement interface in the Permian continental formation at 634 m depth in the SE margin of the Massif Central shield (Ardèche margin of the Southeast basin of France). The fluid sample shows clear water–rock interaction processes, such as feldspar dissolution and kaolinite precipitation, which have led to high Na concentrations and water stable isotopes above the local meteoric water line. The geological formations of the SE margin of the Massif Central shield show that intensive fluid circulation phases occurred across the margin from the late Triassic to the middle Jurassic. The fluids most probably originated from fluid expulsion during burial of the thick Permo-Carboniferous sedimentary succession. These circulation phases were responsible for cementation of the margin and for the solutes in the matrix microporosity which were extracted by leaching core samples. The chemical and isotopic composition of the saline fluid sample at 634 m in the Permian rock is very similar to that of fluids in the microporosity of the rock matrix. Their S SO 4 , O SO 4 and Sr isotopic compositions are close to those of cements investigated in fracture fillings in the same geological formations. Simple diffusion computations and comparison of the chemical composition of the present free fluid sample with matrix porosity fluids indicate that the solutes in the present free fluid sample are related to solutes originating from fluid circulation events which occurred 160–200 Ma ago through their diffusion from the matrix microporosity. A two-stage fluid flow regime is proposed to interpret the chemistry of present and paleo-fluids. (1) During the extensional context (Permian to Cretaceous), basinal brines migrated along the basement/sediment interface after expulsion from the subsiding basin. This fluid migration would be responsible for

  7. The influence of the crystalline basement structures on the petroleum context of the Reconcavo, Brazil; A influencia de estruturas do embasamento cristalino no contexto petrolifero da Bacia sedimentar do Reconcavo

    Energy Technology Data Exchange (ETDEWEB)

    Sapucaia, Najara Santos; Pereira, Cicero da Paixao; Sousa, Daiana Leite de; Silva, Michelangelo Gomes da [Bahia Univ., Salvador, BA (Brazil). Curso de Pos-graduacao em Geofisica]. E-mail: nss@cpgg.ufba.br; cicerocpgg.ufba.br; dls@cpgg.ufba.br; mgs@cpgg.ufba.br

    2003-07-01

    The Reconcavo Basin, a typical example of sedimentary rift basin, is one important Brazilian petroliferous basin. Its structure has been aligned following the pre-Brazilian lithostratigraphic and geotectonic unconformities of the Sao Francisco Craton. This actual work defines some geological context areas of the Reconcavo basin and its crystalline basement, which are registers of great importance for petroleum exploration. The Itanagra target, located at the basin/basement contact, includes the Itanagra-Aracas Fault which has important rift characteristics known as longitudinal accommodation zones (relay zones) responsible for the entrance of sediments in the basin. The Acu da Torre - Rio Pojuca target, located at the basement, suggests the basement control during the rift opening. One on them is the existence of NW-SE oriented lineations in the basement parallel with Mata-Catu and Itanagra-Aracas faults, of sinistral and dextral movements. Another remarkable structure in this target is the parallelism between the basement foliations and gneiss banding, oriented NE-SW, similar to Salvador, Mata-Aracas and Lamarao faults, among others. At last, the Mata de Sao Joao target, located inside the basin, has relevant structures in the configuration of the Reconcavo Basin, as Mata-Catu fault, which controls sin-sedimentary folds. (author)

  8. Effect of basement structure and salt tectonics on deformation styles along strike: An example from the Kuqa fold-thrust belt, West China

    Science.gov (United States)

    Neng, Yuan; Xie, Huiwen; Yin, Hongwei; Li, Yong; Wang, Wei

    2018-04-01

    The Kuqa fold-thrust belt (KFTB) has a complex thrust-system geometry and comprises basement-involved thrusts, décollement thrusts, triangle zones, strike-slip faults, transpressional faults, and pop-up structures. These structures, combined with the effects of Paleogene salt tectonics and Paleozoic basement uplift form a complex structural zone trending E-W. Interpretation and comprehensive analysis of recent high-quality seismic data, field observations, boreholes, and gravity data covering the KFTB has been performed to understand the characteristics and mechanisms of the deformation styles along strike. Regional sections, fold-thrust system maps of the surface and the sub-salt layer, salt and basement structure distribution maps have been created, and a comprehensive analysis of thrust systems performed. The results indicate that the thrust-fold system in Paleogene salt range can be divided into five segments from east to west: the Kela-3, Keshen, Dabei, Bozi, and Awate segments. In the easternmost and westernmost parts of the Paleogene salt range, strike-slip faulting and basement-involved thrusting are the dominant deformation styles, as basement uplift and the limits of the Cenozoic evaporite deposit are the main controls on deformation. Salt-core detachment fold-thrust systems coincide with areas of salt tectonics, and pop-up, imbricate, and duplex structures are associated with the main thrust faults in the sub-salt layer. Distribution maps of thrust systems, basement structures, and salt tectonics show that Paleozoic basement uplift controlled the Paleozoic foreland basin morphology and the distribution of Cenozoic salt in the KFTB, and thus had a strong influence on the segmented structural deformation and evolution of the fold-thrust belt. Three types of transfer zone are identified, based on the characteristics of the salt layer and basement uplift, and the effects of these zones on the fault systems are evaluated. Basement uplift and the boundary of

  9. Nanggulan Formation and Its Problem As a Basement in Kulonprogo Basin, Yogyakarta

    Directory of Open Access Journals (Sweden)

    Hill Gendoet Hartono

    2017-03-01

    Full Text Available DOI: 10.17014/ijog.4.2.71-80Nanggulan Formation consists of the oldest clastic rock sequence exposed in Kulonprogo area, Yogyakarta. This paper discusses the position of Nanggulan Formation as a basement. The method used in this research is surface and subsurface investigations based on gravity surveys. The rock assemblage is exposed and distributed partly in the east flank of Kulonprogo Mountains with weak undulated morphology. The rock sequence is composed of sand to clay grain sizes such as sandstone, quartz sandstone, calcareous sandstone, claystone, fossiliferous claystone, calcareous claystone, siltstone, and coal seam intercalations. The total thickness of the sequence is less than 200 m. Based on the fossil and palynology investigations, previous investigators concluded the age of the rock was Eocene to Middle Miocene. The geological structures developed in the rocks are the lithological stratification, fractures, folding, and faulting. The subsurface interpretation based on gravity data revealed the rock was located under the andesite breccias with 2.44 g/cc density. The density of the rock sequence was 2.63 g/cc. The gravity interpretation shows a strong indication that Nanggulan Formation underlies the andesitic breccias presumably associated with Old Andesite Formation exposed in Kulonprogo Mountains. The limited distribution, the thickness, and the closed environmental deposition of Nanggulan Formation found in the present investigation raised problems on the position of the formation as the basement of Old Andesite Formation occurring in the Kulonprogo Mountain.

  10. Thermal history of the Pan-African basement under the Jurassic Marib-Shabwa Basin, Yemen

    Science.gov (United States)

    Rice, A. Hugh N.; Schneider, David; Veeningen, Resi; Grasemann, Bernhard; Decker, Kurt

    2013-04-01

    Pan-African tectonism within the Arabian Nubian Shield in Yemen is very poorly known. New drill-cores from the Marib-Shabwa Basin (Habban oil field) from central Yemen penetrated 600 m into the pre-Jurassic crystalline basement, providing a unique opportunity to extend our understanding of Pan-African events in Yemen. The cores were obtained some 80 km NE of the exposure limit of the Al Bayda Terrane, which lies SE of Sana'a. This terrane, which has no direct correlative in the ANS further north in Saudi Arabia, comprises deformed greenschist facies acid to basic volcanic rocks later witnessing acid to basic magmatism and has been previously interpreted as a Pan-African island arc complex with a basement component. Ophiolite fragments are common, both within the terrane and at its margins (sutures). To the north lies the Abas Gneiss Terrane and to the south the Al Mahfid Gneiss Terrane; both consist of older pre-Pan-African crystalline basement rocks. Geochemistry of a red, undeformed granite from the drill core indicates an A-type composition. LA-ICPMS U-Pb analysis of granite zircons gave two concordant age populations: 628.3 ± 3.1 Ma (large & small zircons) and 604.9 ± 2.0 Ma (intermediate sized zircons). The former age is interpreted as the time of crystallization, within the range of other A-type Younger Granites in the ANS, and the latter age as constraining lower temperature dissolution-reprecipitation of zircon, due to hydrothermal fluids or melt remobilization. Nd Tdm model ages for two granite samples from the drill core both gave ages of 1.24 Ga, within the range of the Al Bayda Terrane (1.2-2.5 Ga) and outside the range of the adjacent Palaeoproterozoic gneissic terranes (1.7-2.3 Ga, Abas Gneiss Terrane; 1.8-3.0 Ga, Al Mahfid Gneiss Terrane). Thus it seems certain that the Al Bayda Terrane extends at least 80 km to the NE of its present surface exposure. Rb-Sr biotite ages from the granite indicate closure through ~300°C at 593 Ma, indicating fast

  11. Basement and cover-rock deformation during Laramide contraction in the Northern Madison Range (Montana) and its influence on Cenozoic basin formation

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, K.S. [Geological Survey, Denver, CO (United States); Schmidt, C.J. [Western Michigan Univ., Kalamazoo, MI (United States); Young, S.W. [Conoco, Inc., Midland, TX (United States)

    1995-08-01

    Two major Laramide fault systems converge in the northwestern Madison Range: the northwest-striking, southwest-vergent Spanish Peaks reverse fault and the north-striking, east-vergent Hilgard thrust system. Analysis of foliation attitudes in basement gneiss north and south of the Spanish Peaks fault indicates that the basement in thrusted blocks of the Hilgard thrust system has been rotated by an amount similar to that of the basement-cover contact. In most places along the Hilgard thrust system, a large basement overhang, produced by thrusting of Archean blocks above rocks as young as Late Cretaceous, overlies a tight footwall syncline. This tight folding is largely concentric and was accommodated by flexural slip, resulting in severe crowding in synclinal hinges that resulted in observed or inferred features such as bedding-plane slip, imbricate and out-of-syncline thrusting, and hinge collapse. This paired fault system (the Madison normal fault system and the Hilgard thrust system) of the northern Madison Range is strikingly similar to other paired systems in southwestern Montana along and adjacent to the western margins of the Ruby Range, Snowcrest Range, Greenhorn Range, Tobacco Root Mountains, and Bridger Range. No hydrocarbon discoveries have been made in this unique structural province. However, petroleum exploration here has focused on basement-cored anticlines, both surface and subthrust, related to the two major Laramide fault systems and on the fault-bounded blocks of Tertiary rocks within the post-Laramide extensional basins. The interplay of the two Laramide fault systems during both Laramide shortening and Tertiary extension has produced a variety of possible structural traps in the Madison Range that have not yet been thoroughly investigated.

  12. Peroxynitrous acid induces structural and functional modifications to basement membranes and its key component, laminin

    DEFF Research Database (Denmark)

    Degendorfer, Georg; Chuang, Christine Y.; Hammer, Astrid

    2015-01-01

    Basement membranes (BM) are specialized extracellular matrices underlying endothelial cells in the artery wall. Laminin, the most abundant BM glycoprotein, is a structural and biologically active component. Peroxynitrous acid (ONOOH), a potent oxidizing and nitrating agent, is formed in vivo...

  13. Fertility of late Archaean basement granite in the vicinity of U-mineralized Neoproterozoic Bhima basin, peninsular India

    International Nuclear Information System (INIS)

    Senthil Kumar, P.; Srinivasan, R.

    2002-01-01

    Late Archaean granitoids constituting the basement for the Neoproterozoic Bhima Group are exposed along the southern margin of the Bhima basin in southern India. These are rich in accessory minerals such as sphene, allanite, apatite and zircon, which are the main carriers of uranium and thorium. In situ gamma-ray spectrometric analysis reveals that these granitoids have higher abundances of Th, U and K (Th range 10-43 ppm, mean 26 ppm; U range 3-21 ppm, mean 8 ppm; K range 1.2-5.2%, mean 4.0%) relative to granitoids occurring farther away from the basin. Thus, they belong to the class of fertile granitoids from the point of view of uranium mineralization. The granitoids have been mylnotized and hydrothermally altered in the Gugi-Ukkinal fault zone, which constitutes the zone of uranium mineralization discovered recently along the southern margin of the Bhima basin. Uranium apparently derived from hydrothermal leaching of basement granitoid rocks may have got deposited in the fault zone at the contact of carbonate rocks, which provided favourable geochemical environment (Eh-pH conditions) for uranium precipitation. (author)

  14. field occurrence and structural characteristics of basement rocks ...

    African Journals Online (AJOL)

    Global Journal

    NNW/NW- (65.68%). • E - W (8.28%). • NE - SW (26.04%). The brittle structures trend predominantly in the. NNW/NW direction while the ductile structures trend in the. NNE/NE direction. Table 3: Summary of strike azimuth frequency data of structures (foliations, joints/fractures and veins) in the study area. Structural Elements.

  15. One Basin, One Stress Regime, One Orientation of Seismogenic Basement Faults, Variable Spatio-Temporal Slip Histories: Lessons from Fort Worth Basin Induced Earthquake Sequences

    Science.gov (United States)

    DeShon, H. R.; Brudzinski, M.; Frohlich, C.; Hayward, C.; Jeong, S.; Hornbach, M. J.; Magnani, M. B.; Ogwari, P.; Quinones, L.; Scales, M. M.; Stump, B. W.; Sufri, O.; Walter, J. I.

    2017-12-01

    Since October 2008, the Fort Worth basin in north Texas has experienced over 30 magnitude (M) 3.0+ earthquakes, including one M4.0. Five named earthquake sequences have been recorded by local seismic networks: DFW Airport, Cleburne-Johnson County, Azle, Irving-Dallas, and Venus-Johnson County. Earthquakes have occurred on northeast (NE)-southwest (SW) trending Precambrian basement faults and within the overlying Ellenburger limestone unit used for wastewater disposal. Focal mechanisms indicate primarily normal faulting, and stress inversions indicate maximum regional horizontal stress strikes 20-30° NE. The seismogenic sections of the faults in either the basement or within the Ellenburger appear optimally oriented for failure within the modern stress regime. Stress drop estimates range from 10 to 75 bars, with little variability between and within the named sequences, and the values are consistent with intraplate earthquake stress drops in natural tectonic settings. However, the spatio-temporal history of each sequence relative to wastewater injection data varies. The May 2015 M4.0 Venus earthquake, for example, is only the largest of what is nearly 10 years of earthquake activity on a single fault structure. Here, maximum earthquake size has increased with time and exhibits a log-linear relationship to cumulative injected volume from 5 nearby wells. At the DFW airport, where the causative well was shut-in within a few months of the initial earthquakes and soon after the well began operation, we document migration away from the injector on the same fault for nearly 6 km sporadically over 5 years. The Irving-Dallas and Azle sequences, like DFW airport, appear to have started rather abruptly with just a few small magnitude earthquakes in the weeks or months preceding the significant set of magnitude 3.5+ earthquakes associated with each sequence. There are no nearby (<10 km) injection operations to the Irving-Dallas sequence and the Azle linked wells operated for

  16. Field occurrence and structural characteristics of basement rocks ...

    African Journals Online (AJOL)

    Bunu Area in part of Kabba-Lokoja-Igarra Schist Belt, southwestern Nigeria. ... structures in the NW-SE to N-S directions are filled by quartz veins, dolerites and pegmatite dykes and serve as conduits and pathway of the gold bearing ore fluids.

  17. The role of E-W basement faults in the Mesozoic geodynamic evolution of the Gafsa and Chotts basins, south-central Tunisia

    Science.gov (United States)

    Amri, Dorra Tanfous; Dhahri, Ferid; Soussi, Mohamed; Gabtni, Hakim; Bédir, Mourad

    2017-10-01

    The Gafsa and Chotts intracratonic basins in south-central Tunisia are transitional zones between the Atlasic domain to the north and the Saharan platform to the south. The principal aim of this paper is to unravel the geodynamic evolution of these basins following an integrated approach including seismic, well log and gravity data. These data are used to highlight the tectonic control on the deposition of Jurassic and Lower Cretaceous series and to discuss the role of the main faults that controlled the basin architecture and Cretaceous-Tertiary inversion. The horizontal gravity gradient map of the study area highlights the pattern of discontinuities within the two basins and reveals the presence of deep E-W basement faults. Primary attention is given to the role played by the E-W faults system and that of the NW-SE Gafsa fault which was previously considered active since the Jurassic. Facies and thickness analyses based on new seismic interpretation and well data suggest that the E-W-oriented faults controlled the subsidence distribution especially during the Jurassic. The NW-SE faults seem to be key structures that controlled the basins paleogeography during Late Cretaceous-Cenozoic time. The upper Triassic evaporite bodies, which locally outline the main NW-SE Gafsa fault, are regarded as intrusive salt bodies rather than early diapiric extrusions as previously interpreted since they are rare and occurred only along main strike-slip faults. In addition, seismic lines show that Triassic rocks are deep and do not exhibit true diapiric features.

  18. Structural Evolution of the Eastern Sierra Madre Oriental: The Role of Basement Structures in Fold-Thrust Development

    Science.gov (United States)

    Hamade, A.; Murphy, M. A.; Hall, S.

    2006-12-01

    Investigations worldwide show that basement plays an important role in the evolution of fold-thrust belts and recognizing their structural development leads to better understanding of zones of intercontinental deformation. Two explanations have been proposed to explain uplift of basement rocks in the Sierra Madre Oriental (SMO) fold-thrust belt, 1) basement rocks are uplifted along high-angle reverse faults (Laramide-style) which postdate a thin-skinned phase of deformation; and 2) basement rocks are carried in deeper-rooted thrust sheets during the thin-skinned phase of deformation. A structural study in the SMO fold-thrust belt that integrates field mapping, structural analysis, and gravity modeling was conducted to distinguish between the two explanations. The study area lies in the southern section of the state of Nuevo Leon near the town of Aramberri. In this area the fold-thrust belt involves upper Cretaceous shale, Mesozoic carbonate rocks and crystalline basement. Thrusting is directed approximately due east. The structural style is characterized by fault bend folds. Mapping shows that evaporite rocks, at least locally, are not exploited as a regional slip surface and the thrust fault roots into the basement. Cross-sections across the study area indicate approximately 6.5 km east-west shortening (19%). Three forward 2-D structural models aid in constraining the fault geometry at depth and show the reactivation of half graben faults as a means for the main thrust to step up to shallower levels. These data are consistent with a single phase of deformation which involves movement along a thrust system that creates the structure in the study area implying magnitude of depth to detachment to be greater for this area of the SMO.

  19. Structural evolution of Lake Superior I: Western basin

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, B.J.; Wang, H.F. (Univ. of Wisconsin, Madison, WI (United States)); Reynolds, D.J. (Lamont Doherty Geological Observatory, Palisades, NY (United States))

    1992-01-01

    The authors have utilized reflector terminations, reflection character and truncation to interpret a grid of multi-channel seismic reflection profiles collected in the American waters of Lake Superior by Grant-Norpac in 1985. The authors have defined 13 separate reflectors that can be mapped across most of the basin, representing Keweenawan volcanics and sediments of the Jacobsville-Bayfield and Oronto Groups and possibly the early to mid Proterozoic Animikie Group. Structure and isopach maps reveal that the basin is segmented into a series of sub-basins divided by basement highs oblique to the trend of the Lake Superior basin. Unusual is the apparent rarity of extensional structures, which are confined entirely to the extreme western portion of the lake. Reactivation of basin bounding faults as thrusts has been invoked to explain uplift on the Isle Royale and Keweenaw faults. Gravity anomaly data has been interpreted to suggest that the Isle Royal fault is continuous with the Douglas fault in northeastern Wisconsin. The Isle Royale fault terminates west of Isle Royale on the flank of a large basement high. To the west of the termination, deformation is taken up on a blind or intra-stratal thrust which wraps around the basement high. The high is coincident with a distinctive gravity low. It is covered by the sag phase sediments of the Oronto and Jacobsville-Bayfield Groups. The intra-stratal thrust may root below the Keweenawan basalts, suggesting that the basalt section acted as a load bearing member, analogous to carbonate sequences in thrust slices, during the compressional reactivation of the rift structures.

  20. Intrabasement structures as structural templates for rifts: Insights from the Taranaki Basin, offshore New Zealand

    Science.gov (United States)

    Collanega, L.; Jackson, C. A. L.; Bell, R. E.; Lenhart, A.; Coleman, A. J.; Breda, A.; Massironi, M.

    2017-12-01

    Intrabasement structures are often envisaged to have acted as structural templates for normal fault growth in the overlying sedimentary cover during rifting (e.g. East African Rift; NE Brazilian Margin; Norwegian North Sea). However, in some settings, the geometry of rift-related faults is apparently unaffected by pre-existing basement fabric (Måløy Slope and Lofoten Ridge, offshore Norway). Understanding the nucleation and propagation of normal faults in the presence of basement structures may elucidate how and under what conditions basement fabric can exert an influence on rifting. Here, we investigate the 3D geometry of a series of normal faults and intrabasement structures from the Taranaki Basin, offshore New Zealand to understand how normal faults grow in the presence of basement heterogeneities. The Taranaki Basin is an ideal setting because the basement structures, related to the Mesozoic compressional tectonics, are shallow and well-imaged on 3D seismic reflection data, and the relatively thin and stratigraphically simple sedimentary cover is only affected by mild Pliocene extension. Our kinematic analysis highlights two classes of normal faults affecting different vertical intervals of the sedimentary cover. Deep faults, just above the basement, strike NW-SE to NE-SW, reflecting the trend of underlying intrabasement structures. In contrast, shallow faults strike according to the NE-SW to NNE-SSW Pliocene trend and are not generally affected by intrabasement structures at distances >500 m above the basement. Deep and shallow faults are only linked when they strike similarly, and are located above strong intrabasement reflections. We infer that cover deformation is significantly influenced by intrabasement structures within the 500 m interval above the crystalline basement, whereas shallower faults are optimally aligned to the Pliocene regional stress field. Since we do not observe an extensional reactivation of intrabasement structures during Pliocene

  1. Diferentiation of Basements Types Using Seismic Reflection Data and 40Ar-39Ar Dating in the Western Half of the Farallon Basin (gulf of California, Mexico)

    Science.gov (United States)

    Piñero Lajas, D.; González Fernández, A.; López-Martínez, M.; Lonsdale, P.; Kluesner, J.

    2009-04-01

    The Gulf of California is an active continental rift with an oblique right lateral displacement. Defining a clear boundary between continental and oceanic crust is difficult due to the high sedimentation rate. The new crust is a mixture of sills and sediments that do not produce aligned magnetic anomalies. The main objective of this work is to identify this boundary in the western part of the Farallon Basin. In order to accomplish this goal we used multichannel 2D high-resolution seismic reflection data taken during a cruise aboard oceanographic vessel Francisco de Ulloa in 2006. We also used petrological characterization and 40Ar-39Ar dating of continental samples collected in nearby Santa Catalina, Santa Cruz and San Diego islands, Punta Botella in the Baja California Peninsula, and marine samples of the continental margin next to Las Animas island (ROCA 2008 cruise). Oceanic crust created in the Farallòn spreading axis is identified primarily by saucer-shaped structures in the seismic profiles, which are interpreted as sills. The plutonic continental basement is located on the westernmost part of the margin and is recognized by a continuous high amplitude reflector. There are also volcanic patches in this area, like the South Farallon Massif, which are evident as discontinuities in the high amplitude reflector and with a different seismic character. The Farallon Basin is affected by two different tectonic regimes, the first (compressive) is related to the subduction of the Farallon Plate under the North American Plate, when the plutonic basement was originated. It consists of granodiorites and tonalites belonging to two phases of subduction during the Upper Cretaceous and Early Miocene. Outcrops of the latter phase are exposed in the peninsula of Baja California (Conception Bay); Mexico mainland (middle Sinaloa); and dredged samples of Pescadero Basin. These are similar to the plutonic Santa Catalina Island outcrop described and dated in this study. These

  2. Metal-rich fluid inclusions provide new insights into unconformity-related U deposits (Athabasca Basin and Basement, Canada)

    Science.gov (United States)

    Richard, Antonin; Cathelineau, Michel; Boiron, Marie-Christine; Mercadier, Julien; Banks, David A.; Cuney, Michel

    2016-02-01

    The Paleoproterozoic Athabasca Basin (Canada) hosts numerous giant unconformity-related uranium deposits. The scope of this study is to establish the pressure, temperature, and composition (P-T-X conditions) of the brines that circulated at the base of the Athabasca Basin and in its crystalline basement before, during and after UO2 deposition. These brines are commonly sampled as fluid inclusions in quartz- and dolomite-cementing veins and breccias associated with alteration and U mineralization. Microthermometry and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) data from five deposits (Rabbit Lake, P-Patch, Eagle Point, Millennium, and Shea Creek) complement previously published data for the McArthur River deposit. In all of the deposits investigated, fluid inclusion salinity is between 25 and 40 wt.% NaCl equiv., with compositions displaying a continuum between a "NaCl-rich brine" end-member (Cl > Na > Ca > Mg > K) and a "CaCl2-rich brine" end-member (Cl > Ca ≈ Mg > Na > K). The CaCl2-rich brine has the highest salinity and shows evidence for halite saturation at the time of trapping. The continuum of compositions between the NaCl-rich brine and the CaCl2-rich brine end-members combined with P-T reconstructions suggest anisothermal mixing of the two brines (NaCl-rich brine, 180 ± 30 °C and 800 ± 400 bars; CaCl2-rich brine, 120 ± 30 °C and 600 ± 300 bars) that occurred under fluctuating pressure conditions (hydrostatic to supra-hydrostatic). However, because the two brines were U bearing and therefore oxidized, brine mixing was probably not the driving force for UO2 deposition. Several scenarios are put forward to account for the Cl-Na-Ca-Mg-K composition of the brines, involving combinations of seawater evaporation, halite dissolution, mixing with a halite-dissolution brine, Mg/Ca exchange by dolomitization, Na/Ca exchange by albitization of plagioclase, Na/K exchange by albitization of K-feldspar, and Mg loss by Mg

  3. Rb-Sr and K-Ar isotopic evidence for neoproterozoic (Pan-African) granulite metamorphism from the basement of Mumbai offshore basin, India

    International Nuclear Information System (INIS)

    Rathore, S.S.; Vijan, A.R.; Singh, M.P.; Misra, K.N.; Prabhu, B.N.

    2000-01-01

    Precambrian basement from well HBM-1 in the Heera oil field of Mumbai offshore basin has been dated by Rb-Sr and K-Ar methods. Five granulitic basement samples from three conventional drill cores have yielded Rb-Sr isochron age of 502±25 Ma with an initial Sr ratio of 0.70855±0.00013. This age has been interpreted as the time of granulite facies metamorphism of the basement rocks in the region. Two whole rock samples from the basement of this well have yielded mutually concordant K-Ar ages of 505±16 Ma and 507±17 Ma. The K-Ar ages are significantly similar to Rb-Sr age obtained from this well, suggesting complete isotopic reequilibration around 500 Ma ago. The time of secondary thermal heating around 500 Ma ago in the basement of Heera field coincides with the widespread neoproterozoic (Pan-African) thermo-tectonic event extending from the Arabian Peninsula and eastern Africa covering Madagascar, southern India. Sri Lanka and East Antarctica. This study widens the limit of the Pan-African zone, which hitherto was thought to be confined to the western part (presently southern part) of the Indian subcontinent, towards further east. (author)

  4. Crustal structure beneath the Paleozoic Parnaíba Basin revealed by airborne gravity and magnetic data, Brazil

    Science.gov (United States)

    de Castroa, David L.; Fuck, Reinhardt A.; Phillips, Jeffrey D.; Vidotti, Roberta M.; Bezerra, Francisco H. R.; Dantas, Elton L.

    2014-01-01

    The Parnaíba Basin is a large Paleozoic syneclise in northeastern Brazil underlain by Precambrian crystalline basement, which comprises a complex lithostructural and tectonic framework formed during the Neoproterozoic–Eopaleozoic Brasiliano–Pan African orogenic collage. A sag basin up to 3.5 km thick and 1000 km long formed after the collage. The lithologic composition, structure, and role in the basin evolution of the underlying basement are the focus of this study. Airborne gravity and magnetic data were modeled to reveal the general crustal structure underneath the Parnaíba Basin. Results indicate that gravity and magnetic signatures delineate the main boundaries and structural trends of three cratonic areas and surrounding Neoproterozoic fold belts in the basement. Triangular-shaped basement inliers are geophysically defined in the central region of this continental-scale Neoproterozoic convergence zone. A 3-D gravity inversion constrained by seismological data reveals that basement inliers exhibit a 36–40.5 km deep crustal root, with borders defined by a high-density and thinner crust. Forward modeling of gravity and magnetic data indicates that lateral boundaries between crustal units are limited by Brasiliano shear zones, representing lithospheric sutures of the Amazonian and São Francisco Cratons, Tocantins Province and Parnaíba Block. In addition, coincident residual gravity, residual magnetic, and pseudo-gravity lows indicate two complex systems of Eopaleozoic rifts related to the initial phase of the sag deposition, which follow basement trends in several directions.

  5. Structural evolution of Lake Superior II: Eastern basin

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, D.J. (Lamont Doherty Geological Observatory, Palisades, NY (United States)); Coakley, B.J.; Wang, H.F. (Univ. of Wisconsin, Madison, WI (United States). Dept. of Geology and Geophysics)

    1992-01-01

    The authors have interpreted 1,400 km of industry and government multichannel seismic reflection data from eastern Lake Superior. Seismic sequences have been identified by using reflection character and reflector terminations and truncations. This framework, coupled with outcrop information, has allowed them to assign lithologic units to some of these reflectors and reconstruct the timing and geometry of structures within the basin. The authors have mapped the Base Jacobsville-Bayfield Group/Top oronto Group, Base oronto Group/Top Keweenawan volcanics, and Basement as well as several reflectors internal to these groups. Integration of gravity and magnetic data with the seismic grid permits regional mapping of faults and folds between seismic lines. In the eastern part of the basin, high-angle basement-involved reverse faults, such as the southeastern combination of the Keweenaw fault, trend NNW-SSE, while broad folds trend E-W. The Keweenaw fault is a complex structural zone and, in the Manitou Island region, steeply-dipping reflectors with abrupt dip reversals indicate a transpressive flower structure. Reactivation of the Keweenaw fault along the southern margin of the basin has rotated and uplifted the basin fill. This region is where the unconformity on top of the Oronto Group is best developed and shows that much of the compressive motion on this fault system occurred post-Oronto and syn-Jacobsville as the top of Jacobsville Group reflector is only slightly deformed. The stratal relationships seen in the seismic data suggest that compressive deformation was synchronous with Oronto and early Jacobsville deposition.

  6. Structural Controls on Groundwater Flow in Basement Terrains: Geophysical, Remote Sensing, and Field Investigations in Sinai

    KAUST Repository

    Mohamed, Lamees

    2015-07-09

    An integrated [very low frequency (VLF) electromagnetic, magnetic, remote sensing, field, and geographic information system (GIS)] study was conducted over the basement complex in southern Sinai (Feiran watershed) for a better understanding of the structural controls on the groundwater flow. The increase in satellite-based radar backscattering values following a large precipitation event (34 mm on 17–18 January 2010) was used to identify water-bearing features, here interpreted as preferred pathways for surface water infiltration. Findings include: (1) spatial analysis in a GIS environment revealed that the distribution of the water-bearing features (conductive features) corresponds to that of fractures, faults, shear zones, dike swarms, and wadi networks; (2) using VLF (43 profiles), magnetic (7 profiles) techniques, and field observations, the majority (85 %) of the investigated conductive features were determined to be preferred pathways for groundwater flow; (3) northwest–southeast- to north–south-trending conductive features that intersect the groundwater flow (southeast to northwest) at low angles capture groundwater flow, whereas northeast–southwest to east–west features that intersect the flow at high angles impound groundwater upstream and could provide potential productive well locations; and (4) similar findings are observed in central Sinai: east–west-trending dextral shear zones (Themed and Sinai Hinge Belt) impede south to north groundwater flow as evidenced by the significant drop in hydraulic head (from 467 to 248 m above mean sea level) across shear zones and by reorientation of regional flow (south–north to southwest–northeast). The adopted integrated methodologies could be readily applied to similar highly fractured basement arid terrains elsewhere. © 2015 Springer Science+Business Media Dordrecht

  7. Synchronous egress and ingress fluid flow related to compressional reactivation of basement faults: the Phoenix and Gryphon uranium deposits, southeastern Athabasca Basin, Saskatchewan, Canada

    Science.gov (United States)

    Li, Zenghua; Chi, Guoxiang; Bethune, Kathryn M.; Eldursi, Khalifa; Thomas, David; Quirt, David; Ledru, Patrick

    2018-02-01

    Previous studies on unconformity-related uranium deposits in the Athabasca Basin (Canada) suggest that egress flow and ingress flow can develop along single fault systems at different stages of compressional deformation. This research aims to examine whether or not both ingress and egress flow can develop at the same time within an area under a common compressional stress field, as suggested by the reverse displacement of the unconformity surface by the basement faults. The study considers the Phoenix and Gryphon uranium deposits in the Wheeler River area in the southeastern part of the Athabasca Basin. Two-dimensional numerical modeling of fluid flow, coupled with compressional deformation and thermal effects, was carried out to examine the fluid flow pattern. The results show that local variations in the basement geology under a common compressional stress field can result in both egress and ingress flow at the same time. The fault zone at Phoenix underwent a relatively low degree of deformation, as reflected by minor reverse displacement of the unconformity, and egress flow developed, whereas the fault zone at Gryphon experienced a relatively high degree of deformation, as demonstrated by significant reverse displacement of the unconformity, and ingress flow was dominant. The correlation between strain development and location of uranium mineralization, as exemplified by Gryphon and Phoenix uranium deposits, suggests that the localization of dilation predicted by numerical modeling may represent favourable sites for uranium mineralization in the Athabasca Basin.

  8. Chitosan facilitates structure formation of the salivary gland by regulating the basement membrane components.

    Science.gov (United States)

    Yang, Tsung-Lin; Hsiao, Ya-Chuan

    2015-10-01

    Tissue structure is important for inherent physiological function and should be recapitulated during tissue engineering for regenerative purposes. The salivary gland is a branched organ that is responsible for saliva secretion and regulation. The salivary glands develop from epithelial-mesenchymal interactions, and depend on the support of the basement membrane (BM). Chitosan-based biomaterials have been demonstrated to be competent in facilitating the formation of salivary gland tissue structure. However, the underlying mechanisms have remained elusive. In the developing submandibular gland (SMG), the chitosan effect was found to diminish when collagen and laminin were removed from cultured SMG explants. Chitosan increased the expression of BM components including collagen, laminin, and heparan sulfate proteoglycan, and also facilitated BM components and the corresponding receptors to be expressed in tissue-specific patterns beneficial for SMG branching. The chitosan effect decreased when either laminin components or receptors were inhibited, as well when the downstream signaling was blocked. Our results revealed that chitosan promotes salivary glands branching through the BM. By regulating BM components and receptors, chitosan efficiently stimulated downstream signaling to facilitate salivary gland branching. The present study revealed the underlying mechanism of the chitosan effect in engineering SMG structure formation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. The morphology and nature of the East Arctic ocean acoustic basement

    Science.gov (United States)

    Rekant, Pavel

    2017-04-01

    As the result of the thorough interpretation and cross-correlation of the large seismic dataset (>150000 km and >600 seismic lines), the depth structure map of the acoustic basement was constrained. Tectonic framework, basement surface morphology and linkage of the deep basin structures with shelves ones, was significantly clarified based on the map. It becomes clear that most morphostructures presently located within deep-water basin are tectonically connected with shelf structures. Acoustic basement contains a number of pre-Cambrian, Caledonian and Mesozoic consolidated blocks. The basement heterogeneity is highlighted by faults framework and basement surface morphology differences, as well thickness and stratigraphy of the sediment cover. The deepest basins of the East Arctic - Hanna Trough, North Chukchi and Podvodnikov Basins form a united mega-depression, wedged between pre-Cambrian continental blocks (Chukchi Borderland - Mendeleev Rise - Toll Saddle) from the north and the Caledonian deformation front from the south. The basement age/origin speculations are consistent with paleontological and U-Pb zircon ages from dredged rock samples. Most of morphological boundaries in the modern Arctic differ considerably from the tectonic framework. Only part of the Arctic morphostructures is constrained by tectonic boundaries. They are: eastern slope of the Lomonosov Ridge, continental slope in the Laptev Sea, upper continental slope in the Podvodnikov Basin, southern slope of the North Chukchi Basin and borders of the Chukchi Borderland. The rest significant part of modern morphological boundaries are caused by sedimentation processes.

  10. TECTONIC ZONING OF THE SEDIMENTARY COVER IN THE DERYUGIN BASIN OF THE SEA OF OKHOTSK BASED ON STRUCTURAL-MATERIAL (LITHOPHYSICAL) INDICATORS

    OpenAIRE

    V. P. Semakin; A. V. Kochergin

    2013-01-01

    In terms of tectonics, the Deryugin basin (Fig. 1) is a part of the epi-Mesozoic Okhotsk plate comprising the heterogeneous basement that is mainly pre-Cenozoic (the lower structural stage) and the sedimentary cover that is mainly represented by the Paleogenic-Neogenic-Quaternary deposits with the Upper Cretaceous sedimentary rocks observed locally without a visible hiatus (the upper structural stage).The acoustic basement (AB) is composed of the metamorphosed Upper Cretaceous-Paleogenic silt...

  11. Structural interpretation of the Konkan basin, southwestern continental margin of India, based on magnetic and bathymetric data

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, V.; Krishna, K.S.; Murty, G.P.S.; Rao, D.G.; Ramana, M.V.; Rao, M.G.

    Magnetic and bathymetric studies on the Konkan basin of the southwestern continental margin of India reveal prominent NNW-SSE, NW-SE, ENE-WSW, and WNE-ESE structural trends. The crystalline basement occurs at about 5-6 km below the mean sea level. A...

  12. Heparan sulfate proteoglycans made by different basement-membrane-producing tumors have immunological and structural similarities

    DEFF Research Database (Denmark)

    Wewer, U M; Albrechtsen, R; Hassell, J R

    1985-01-01

    Using immunological assays, we determined the relationship between the heparan sulfate proteoglycans produced by two different murine basement-membrane-producing tumors, i.e., the mouse Engelbreth-Holm-Swarm (EHS) tumor and the L2 rat yolk-sac tumor. Antibodies prepared against the heparan sulfate...... mainly heparan sulfate (75%) along with smaller amounts of chondroitin sulfate (19%), whereas the L2 rat yolk-sac tumor produced mainly chondroitin sulfate (76%) with smaller amounts of heparan sulfate (21%). We conclude that these two murine basement-membrane-producing tumors elaborate...

  13. S-wave velocity structures of the Taipei Basin, Taiwan, using microtremor array measurements

    Science.gov (United States)

    Huang, Huey-Chu; Wu, Cheng-Feng; Lee, Feng-Mei; Hwang, Ruey-Der

    2015-04-01

    The S-wave velocity structures of the Taipei Basin in Taiwan are investigated using the array records of microtremors at 15 sites. Dispersion curves at these sites are calculated using the frequency-wavenumber (F-K) spectrum method. The S-wave velocity structures in the Taipei Basin are then estimated by employing surface wave inversion technique. Harder strata sites have higher phase velocities than softer sites. If the S-wave velocity of the Tertiary Basement is assumed to be 1000 m/s, then the Quaternary alluvial thicknesses in the Taipei Basin are between about 100 m and 650 m. The thickness of the alluvium gradually increases from the southeast to the northwest. The inversion results are also in good agreement with well-logging data and seismic reflection studies of the Taipei Basin. The study concludes that microtremor array measurement is a useful tool for estimating S-wave velocity structure.

  14. Anomalous uranium concentration in Archaean basement Shear at Dhani Basri and its significance on Southern Margin of Alwar sub-basin, Rajasthan

    International Nuclear Information System (INIS)

    Panigrahi, B.; Shaji, T.S.; Sharma, G.S.; Yadav, O.P.; Nanda, L.K.

    2008-01-01

    Prominent shear zones cutting through the basement and cover rocks of Delhi Supergroup have been recognized in Dhani Basri - Ramewala sector of Dausa district, Rajasthan. One such shear zone traversing the granite gneiss (Archaean basement) has been observed at Dhani Basri. The sheared rock is exposed in the form of a small hump and gives appearance of quartzite due to intense silicification. Grab samples collected from the shear zone rock analysed upto 93 ppm U 3 O 8 and <10 ppm ThO 2 , which is anomalous in comparison to unsheared rock which analysed 51 ppm eU 3 O 8 , upto 5 ppm U 3 O 8 and 80 ppm ThO 2 . Gamma-ray logging of boreholes drilled by GSI across this shear zone indicated uranium mineralization of the order of 0.030% eU 3 O 8 x 5.40 m and the primary radioactive mineral has been identified as uraninite. The extension of Dhani Basri shear zone inside the cover rocks of Meso-Proterozoic Delhi Supergroup of rocks of Alwar sub-basin is of paramount importance in locating unconformity related as well as hydrothermal vein type uranium mineralization. (author)

  15. Laramide structure of the central Sangre de Cristo Mountains and adjacent Raton Basin, southern Colorado

    Science.gov (United States)

    Lindsey, D.A.

    1998-01-01

    Laramide structure of the central Sangre de Cristo Mountains (Culebra Range) is interpreted as a system of west-dipping, basement-involved thrusts and reverse faults. The Culebra thrust is the dominant structure in the central part of the range; it dips 30 -55?? west and brings Precambrian metamorphic base-ment rocks over unmetamorphosed Paleozoic rocks. East of the Culebra thrust, thrusts and reverse faults break the basement and overlying cover rocks into north-trending fault blocks; these boundary faults probably dip 40-60?? westward. The orientation of fault slickensides indicates oblique (northeast) slip on the Culebra thrust and dip-slip (ranging from eastward to northward) movement on adjacent faults. In sedimentary cover rocks, east-vergent anticlines overlie and merge with thrusts and reverse faults; these anticlines are interpreted as fault-propagation folds. Minor east-dipping thrusts and reverse faults (backthrusts) occur in both the hanging walls and footwalls of thrusts. The easternmost faults and folds of the Culebra Range form a continuous structural boundary between the Laramide Sangre de Cristo highland and the Raton Basin. Boundary structures consist of west-dipping frontal thrusts flanked on the basinward side by poorly exposed, east-dipping backthrusts. The backthrusts are interpreted to overlie structural wedges that have been emplaced above blind thrusts in the basin margin. West-dipping frontal thrusts and blind thrusts are interpreted to involve basement, but backthrusts are rooted in basin-margin cover rocks. At shallow structural levels where erosion has not exposed a frontal thrust, the structural boundary of the basin is represented by an anticline or monocline. Based on both regional and local stratigraphic evidence, Laramide deformation in the Culebra Range and accompanying synorogenic sedimentation in the western Raton Basin probably took place from latest Cretaceous through early Eocene time. The earliest evidence of uplift and

  16. Geological Structure of the Basement of Western and Eastern Parts of the West-Siberian Plain

    Science.gov (United States)

    Ivanov, Kirill S.; Erokhin, Yuriy V.; Ponomarev, Vladimir S.; Pogromskaya, Olga E.; Berzin, Stepan V.

    2016-01-01

    The U-Pb dating (SHRIMP-II on zircon) was obtained for the first time from the basement of the West Siberian Plain in the Western half of the region. It is established that a large part of the protolith of the metamorphic depth in the Shaim-Kuznetsov meganticlinorium contained sedimentary late- and middle-Devonian rocks (395-358 million years).…

  17. Structural analysis of an outcropping granite (Proterozoic basement of Yémen): faults and fractures distributions and scaling properties.

    Science.gov (United States)

    Le Garzic, Edouard; de L'Hamaide, Thibaut; Diraison, Marc; Géraud, Yves; de Urreiztieta, Marc; Hauville, Benoit; Champanhet, Jean-Michel

    2010-05-01

    Numerous deep fractured reservoirs in basement have risen in recent years for oil or geothermal production. Such reservoirs are often badly-known because of a lack of direct information. Indeed, structural models proposed are mostly based on 1D borehole data, and conventional geophysical methods like seismic profiles are not so good techniques to image basement structures. Therefore, understanding the effects of scale in the organization of fracture system is a key problem in modelling geometry of deep fractured reservoir. The aim of this study is to present a detailed structural analysis of an outcropping granite at different scales and to contribute to comprehension of scaling properties of faults systems. Multi-scale structural maps were produced by remote sensing techniques and field approaches in the granitic Proterozoic basement of Al-Mukalla (Yémen). This region, located at the Southern boundary of the Arabian Plate, has a Pan-African tectonic signature and then has undergone two phases of continental extension since Mesozoic times: Jurassic-Cretaceous and Oligo-Miocene rifting (i.e. Gulf of Aden opening). In a first time, very high resolution satellite imagery (QUICKBIRD) was used to construct map of structural lineaments from regional scale to micro-block scale (~1 km x 1 km). In a second time, field observations and fractures measurements performed at outcrop scale allow us to confirm suitability of satellite picking. Finally, description of the various structures existing in Burum's granite and characterization of geometrical and morphological features of faults, fractured corridors and joints enable us to interpret structural lineaments with better accuracy. Major faults strike N090°E and N120°E, whereas secondary structures strike N000°E and N040°E and are interpreted as minor faults, fractured corridors or joints. Consequently, brittle deformation is mainly characterised by structural blocks with parallelogram shaped with fault segments

  18. Detailed petrographic-structural study of an outcrop of Crystalline Basement of Montevideo

    International Nuclear Information System (INIS)

    Pascale, A.; Oyhantçabal, P.

    2010-01-01

    Preliminary data analysis of detailed outcrop Punta Virgilo, located on the S E coast of the department of Montevideo are presented. The investigated outcrop includes gneisses, amphibolite s and several generations of pegmatite and aplite dikes of Paleoproterozoic metamorphic basement, plus a set of dikes emplaced lamprófido exhumed once the area. Petrographic and microstructural studies of metamorphic units allowed to determine the conditions of metamorphism and deformation temperature between 520-720 ° C and pressure between 2 and 6 kbar (depth of 10 to 23 km)

  19. Investigation of the deep structure of the Sivas Basin (innereast Anatolia, Turkey) with geophysical methods

    Science.gov (United States)

    Onal, K. Mert; Buyuksarac, Aydin; Aydemir, Attila; Ates, Abdullah

    2008-11-01

    Sivas Basin is the easternmost and third largest basin of the Central Anatolian Basins. In this study, gravity, aeromagnetic and seismic data are used to investigate the deep structure of the Sivas Basin, together with the well seismic velocity data, geological observations from the surface and the borehole data of the Celalli-1 well. Basement depth is modeled three-dimensionally (3D) using the gravity anomalies, and 2D gravity and magnetic models were constructed along with a N-S trending profile. Densities of the rock samples were obtained from the distinct parts of the basin surface and in-situ susceptibilities were also measured and evaluated in comparison with the other geophysical and geological data. Additionally, seismic sections, in spite of their low resolution, were used to define the velocity variation in the basin in order to compare depth values and geological cross-section obtained from the modeling studies. Deepest parts of the basin (12-13 km), determined from the 3D model, are located below the settlement of Hafik and to the south of Zara towns. Geometry, extension and wideness of the basin, together with the thickness and lithologies of the sedimentary units are reasonably appropriate for further hydrocarbon exploration in the Sivas Basin that is still an unexplored area with the limited number of seismic lines and only one borehole.

  20. Seismic Structural Setting of Western Farallon Basin, Southern Gulf of California, Mexico.

    Science.gov (United States)

    Pinero-Lajas, D.; Gonzalez-Fernandez, A.; Lopez-Martinez, M.; Lonsdale, P.

    2007-05-01

    Data from a number of high resolution 2D multichannel seismic (MCS) lines were used to investigate the structure and stratigraphy of the western Farallon basin in the southern Gulf of California. A Generator-Injector air gun provided a clean seismic source shooting each 12 s at a velocity of 6 kts. Each signal was recorded during 6- 8 s, at a sampling interval of 1 ms, by a 600 m long digital streamer with 48 channels and a spacing of 12.5 m. The MCS system was installed aboard CICESE's (Centro de Investigacion Cientifica y de Educacion Superior de Ensenada) 28 m research vessel Francisco de Ulloa. MCS data were conventionally processed, to obtain post- stack time-migrated seismic sections. The MCS seismic sections show a very detailed image of the sub-bottom structure up to 2-3 s two-way travel time (aprox. 2 km). We present detailed images of faulting based on the high resolution and quality of these data. Our results show distributed faulting with many active and inactive faults. Our study also constrains the depth to basement near the southern Baja California eastern coast. The acoustic basement appears as a continuous feature in the western part of the study area and can be correlated with some granite outcrops located in the southern Gulf of California islands. To the East, near the center of the Farallon basin, the acoustic basement changes, it is more discontinuous, and the seismic sections show a number of diffracted waves.

  1. Magnetic constraints of basement structure offshore of western Kyushu, Japan; Kyushu seiho kaiiki ni okeru jiki ijo no kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Okuma, S.; Nakatsuka, T. [Geological Survey of Japan, Tsukuba (Japan); Ishihara, T. [Japan National Oil Corp., Tokyo (Japan)

    1996-05-01

    This paper describes the results from the qualitative analysis of magnetic anomalies offshore of western Kyushu and from an analysis by a three-dimensional two-layer model inversion. The analysis ranged from Kyushu on the east to Jeju Island on the west and from the southern part of the Korean Peninsula on the north to Tanegashima and Yakushima Islands on the south, namely, the area of 580km from east to west and 580km from south to north. The analytical data used was Magnetic Anomaly Map of Asia (GSJ and CCOP, 1994). In the qualitative analysis, a pseudogravity anomaly map and a pole gravity anomaly map were prepared from the total magnetic force anomaly map by means of a frequency filter operation. As a result, it was noted that two distinctive magnetic high belts existed in the margin of the Tunghai Shelf, extending from the sea area to the west of the Nansei Islands continuously to NNE, and being distributed transversely through the Goto sedimentary basin. Additionally, in the inversion analysis, it was demonstrated that the magnetic basement became shallow at the margin of the Tunghai Shelf north of latitude 31 degrees north, extending nearly in the NNE direction through west of the Goto Islands, west of Tsushima Island, and continuing to the southern coast of the Korean Peninsula. 6 refs., 4 figs.

  2. Protein structure prediction using basin-hopping

    Science.gov (United States)

    Prentiss, Michael C.; Wales, David J.; Wolynes, Peter G.

    2008-06-01

    Associative memory Hamiltonian structure prediction potentials are not overly rugged, thereby suggesting their landscapes are like those of actual proteins. In the present contribution we show how basin-hopping global optimization can identify low-lying minima for the corresponding mildly frustrated energy landscapes. For small systems the basin-hopping algorithm succeeds in locating both lower minima and conformations closer to the experimental structure than does molecular dynamics with simulated annealing. For large systems the efficiency of basin-hopping decreases for our initial implementation, where the steps consist of random perturbations to the Cartesian coordinates. We implemented umbrella sampling using basin-hopping to further confirm when the global minima are reached. We have also improved the energy surface by employing bioinformatic techniques for reducing the roughness or variance of the energy surface. Finally, the basin-hopping calculations have guided improvements in the excluded volume of the Hamiltonian, producing better structures. These results suggest a novel and transferable optimization scheme for future energy function development.

  3. Geological structure of Osaka basin and characteristic distributions of structural damage caused by earthquake; Osaka bonchi kozo to shingai tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, K.; Shiono, K.; Inoue, N.; Senda, S. [Osaka City University, Osaka (JP. Faculty of Science); Ryoki, K. [Osaka Polytechnic Collage, Osaka (Japan); Shichi, R. [Nagoya University, Nagoya (Japan). Faculty of Science

    1996-05-01

    The paper investigates relations between the damage caused by the Hyogo-ken Nanbu earthquake and the deep underground structures. A characteristic of the earthquake damage distribution is that the damage concentrated near faults. Most of the damages were seen on the side of faults` relatively falling rather than right above the faults and of their slightly slanting to the seaside. Distribution like this seems to be closely related to underground structures. Therefore, a distribution map of the depth of basement granite in Osaka sedimentary basin was drawn, referring to the data on basement rock depth obtained from the distribution map of gravity anomaly and the result of the survey using the air gun reflection method. Moreover, cubic underground structures were determined by 3-D gravity analysis. The result was concluded as follows: when observing the M7 zone of the low land, in particular, where the damage was great from an aspect of gravity anomaly, the basement rock below the zone declined near the cliff toward the sea, which indicates a great possibility of its being a fault. There is a high possibility that the zone suffered mostly from the damage caused by focusing by refraction and total reflection of seismic wave rays. 3 refs., 8 figs.

  4. Site-effect estimations for Taipei Basin based on shallow S-wave velocity structures

    Science.gov (United States)

    Chen, Ying-Chi; Huang, Huey-Chu; Wu, Cheng-Feng

    2016-03-01

    Shallow S-wave velocities have been widely used for earthquake ground-motion site characterization. Thus, the S-wave velocity structures of Taipei Basin, Taiwan were investigated using array records of microtremors at 15 sites (Huang et al., 2015). In this study, seven velocity structures are added to the database describing Taipei Basin. Validity of S-wave velocity structures are first examined using the 1D Haskell method and well-logging data at the Wuku Sewage Disposal Plant (WK) borehole site. Basically, the synthetic results match well with the observed data at different depths. Based on S-wave velocity structures at 22 sites, theoretical transfer functions at five different formations of the sedimentary basin are calculated. According to these results, predominant frequencies for these formations are estimated. If the S-wave velocity of the Tertiary basement is assumed to be 1000 m/s, the predominant frequencies of the Quaternary sediments are between 0.3 Hz (WUK) and 1.4 Hz (LEL) in Taipei Basin while the depths of sediments between 0 m (i.e. at the edge of the basin) and 616 m (i.e. site WUK) gradually increase from southeast to northwest. Our results show good agreement with available geological and geophysical information.

  5. Structure and tectonic evolution of the Southern Eurasia Basin, Arctic Ocean

    Science.gov (United States)

    Sekretov, Sergey B.

    2002-07-01

    Multichannel seismic reflection data acquired by Marine Arctic Geological Expedition (MAGE) of Murmansk, Russia in 1990 provide the first view of the geological structure of the Arctic region between 77-80°N and 115-133°E, where the Eurasia Basin of the Arctic Ocean adjoins the passive-transform continental margin of the Laptev Sea. South of 80°N, the oceanic basement of the Eurasia Basin and continental basement of the Laptev Sea outer margin are covered by 1.5 to 8 km of sediments. Two structural sequences are distinguished in the sedimentary cover within the Laptev Sea outer margin and at the continent/ocean crust transition: the lower rift sequence, including mostly Upper Cretaceous to Lower Paleocene deposits, and the upper post-rift sequence, consisting of Cenozoic sediments. In the adjoining Eurasia Basin of the Arctic Ocean, the Cenozoic post-rift sequence consists of a few sedimentary successions deposited by several submarine fans. Based on the multichannel seismic reflection data, the structural pattern was determined and an isopach map of the sedimentary cover and tectonic zoning map were constructed. A location of the continent/ocean crust transition is tentatively defined. A buried continuation of the mid-ocean Gakkel Ridge is also detected. This study suggests that south of 78.5°N there was the cessation in the tectonic activity of the Gakkel Ridge Rift from 33-30 until 3-1 Ma and there was no sea-floor spreading in the southernmost part of the Eurasia Basin during the last 30-33 m.y. South of 78.5°N all oceanic crust of the Eurasia Basin near the continental margin of the Laptev Sea was formed from 56 to 33-30 Ma.

  6. Basement characterization and crustal structure beneath the Arabia-Eurasia collision (Iran): A combined gravity and magnetic study

    Science.gov (United States)

    Mousavi, Naeim; Ebbing, Jörg

    2018-04-01

    We present a study on the depth to basement and magnetic crustal domains beneath the Iranian Plateau by modeling aeromagnetic and gravity data. First, field processing of the aeromagnetic data was undertaken to estimate the general characteristics of the magnetic basement. Afterwards, inverse modeling of aeromagnetic data was carried out to estimate the depth to basement. The obtained model of basement was refined using combined gravity and magnetic forward modeling. Hereby, we were able to distinguish different magnetic domains in the uppermost crust (10-20 km depths) influencing the medium to long wavelength trends of the magnetic anomalies. Magnetic basement mapping shows that prominent shallow magnetic features are furthermore located in the volcanic areas, e.g. the Urumieh Dokhtar Magmatic Assemblage. The presence of ophiolite outcrops in SE Iran implies that shallow oceanic crust (with high magnetization) is the main source of one of the biggest magnetic anomalies in entire Iran area located north of the Makran.

  7. Deep Structure and Subsidence of Parnaíba Cratonic Basin, NE Brazil

    Science.gov (United States)

    Rodríguez Tribaldos, V.; White, N. J.; Coelho, D. L. O.; Julià, J.

    2016-12-01

    Cratonic basins are typically underlain by thick lithosphere and slowly subside over hundreds of millions of years. Their stratigraphy consist of unconformity-bounded sequences of continental and shallow marine sedimentary rocks. The origin and evolution of these basins remain enigmatic. Here, we address this problem by carrying out an integrative study of the Parnaíba cratonic basin in NE Brazil. We analyse a 1400 km long deep seismic reflection profile crossing the basin, teleseismic earthquakes recorded by 9 broadband and 10 short-period, 3 component seismometers, 25 ancillary seismic reflection profiles, and 46 wells distributed throughout the basin. Our aim is to constrain subsidence histories in the context of crustal structure and basin architecture. Combined interpretation of the deep seismic profile and 1D velocity models calculated by joint inversion of receiver functions and surface wave dispersion curves locates the Moho at 39 km beneath the city of Teresina on the basin's eastern region. At the eastern edge of the basin, the Moho lies at 37 km beneath Precambrian basement. In the centre of the basin, the Moho lies at 37 km. Beneath Teresina, an increase in S wave velocity at 30 km coincides with mid-crustal reflections on the deep seismic profile. This feature is interpreted as the top of a high-velocity body within the crust. Ancillary seismic profiles show that the stratigraphy is divisible into packages of undisturbed reflections separated by bright, rugged reflections that resemble buried paleolandscapes. Correlation of seismic profiles with well logs shows that these surfaces are basin-wide erosional unconformities that are observable in outcrop. Backstripped and water-loaded subsidence curves show exponential decrease in subsidence over the last 400 Ma. This background subsidence is punctuated by departures from the long-term trend at times when unconformities occur, which we interpret as mild regional uplift events.

  8. Determination of Cenozoic sedimentary structures using integrated geophysical surveys: A case study in the Barkol Basin, Xinjiang, China

    Science.gov (United States)

    Sun, Kai; Chen, Chao; Du, Jinsong; Wang, Limin; Lei, Binhua

    2018-01-01

    Thickness estimation of sedimentary basin is a complex geological problem, especially in an orogenic environment. Intense and multiple tectonic movements and climate changes result in inhomogeneity of sedimentary layers and basement configurations, which making sedimentary structure modelling difficult. In this study, integrated geophysical methods, including gravity, magnetotelluric (MT) sounding and electrical resistivity tomography (ERT), were used to estimate basement relief to understand the geological structure and evolution of the eastern Barkol Basin in China. This basin formed with the uplift of the eastern Tianshan during the Cenozoic. Gravity anomaly map revealed the framework of the entire area, and ERT as well as MT sections reflected the geoelectric features of the Cenozoic two-layer distribution. Therefore, gravity data, constrained by MT, ERT and boreholes, were utilized to estimate the spatial distribution of the Quaternary layer. The gravity effect of the Quaternary layer related to the Tertiary layer was later subtracted to obtain the residual anomaly for inversion. For the Tertiary layer, the study area was divided into several parts because of lateral difference of density contrasts. Gravity data were interpreted to determine the density contrast constrained by the MT results. The basement relief can be verified by geological investigation, including the uplift process and regional tectonic setting. The agreement between geophysical survey and prior information from geology emphasizes the importance of integrated geophysical survey as a complementary means of geological studies in this region.

  9. Structural imaging of the East Beni Sueif Basin, north eastern Desert, Egypt

    Science.gov (United States)

    Salem, E.; Sehim, A.

    2017-12-01

    The East Beni Sueif Basin is the only tested hydrocarbon-bearing basin on the eastern side of the Nile in Egypt. The basin is located around 150 km to the south of Cairo. This work introduces the first attempt of seismic interpretation and structural patterns of this basin, for which subsurface published works are lacking. Structural imaging of the area is achieved through interpretation of pre-stack time migration (PSTM) seismic cube and data sets of seven wells. The penetrated sedimentary section is represented by Albian-Middle Eocene sediments. The East Beni Sueif Basin is a type of the whole graben-system and is bounded by two NW-SE bounding faults. These faults had continued activity in an extensional regime associated with fault-propagating folds. The basin is traversed by a N75°E-trending fault system at basement level. This fault system separates the basin into two structural provinces. The Northwestern Province is deeper and shows more subsidence with a predominance of NW-trending longitudinal faults and N60·W oblique faults to the basin trend. The Southeastern Province is shallow and crossed by N14·W-trending faults which are slightly oblique to the basin axis. Albian time had witnessed the main extensional tectonic phase and resulted in major subsidence along basin-bounding faults associated with growth thickening of basal deposits. During Senonian time, the basin experienced a mild phase of transtensional tectonics, which formed negative-flower structures entrapping different folds along the N75°E and N60·W faults. The timing and style of these structures are similar to the Syrian-Arc structures in several Western Desert oil fields. The basin emerged during the Paleocene with scoured and eroded top Cretaceous sediments. Subsidence was resumed during the Early Eocene and resulted in 1500 m-thick carbonate sediments. Lastly, a mild extensional activity possibly occurred during the Oligocene-Miocene time. Despite the possible restricted potentiality

  10. Inferring the subsurface basement depth and the structural trends as deduced from aeromagnetic data at West Beni Suef area, Western Desert, Egypt

    Science.gov (United States)

    Khalil, Ahmed; Abdel Hafeez, Tharwat H.; Saleh, Hassan S.; Mohamed, Waheed H.

    2016-12-01

    The present work aimed to delineate the subsurface structures and to estimate the magnetic source depth at the selected area lying in West Beni Suef area, Western Desert, Egypt, following different geomagnetic techniques. The analysis of aeromagnetic data demonstrates five significant tectonic faults trending to NW-SE, ENE-WSW, NE-SW, E-W and NNW-SSE directions constructed using Euler deconvolution techniques. The execution of this study is initiated by transformation of the total intensity aeromagnetic data to the reduced to pole (RTP) magnetic intensity. This is followed by applying several transformation techniques and various filtering processes through qualitative and quantitative analyses on magnetic data. The reduced to the northern magnetic pole (RTP) data are separated spectrally into regional and residual magnetic components using the computed power spectrum of the magnetic data. The estimated mean depths of both regional and residual sources are found to be 5.27 km and 2.78 km respectively. Also, depth estimations have been conducted by application of the Euler deconvolution and 2-D modeling techniques. The results indicate that the eastern and northern parts of the study area discriminate deeper basement relief and the depth of basement surface reaches to 5095 m. While the southern and western parts of the study area discriminate shallower basement relief and the depth of basement surface reaches to 227 m. This study has given a clear picture of the geologic structures beneath the study area.

  11. The Central European Permian Basins; Rheological and structural controls on basin history and on inter-basin connectivity

    NARCIS (Netherlands)

    Smit, Jeroen; van Wees, Jan-Diederik; Cloetingh, Sierd

    2014-01-01

    We analyse the relative importance of the major crustal-scale fault zones and crustal architecture in controlling basin formation, deformation and the structural connections between basins. The North and South Permian Basins of Central Europe are usually defined by the extend of Rotliegend

  12. Cell invasion through basement membrane

    Science.gov (United States)

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recently discovered that invadopodia breach basement membrane during anchor cell invasion in C. elegans, a genetically and visually tractable in vivo invasion event. Further, we found that the netrin receptor DCC localizes to the initial site of basement membrane breach and directs invasion through a single gap in the matrix. In this commentary, we examine how the dynamics and structure of AC-invadopodia compare with in vitro invadopodia and how the netrin receptor guides invasion through a single basement membrane breach. We end with a discussion of our surprising result that the anchor cell pushes the basement membrane aside, instead of completely dissolving it through proteolysis, and provide some ideas for how proteases and physical displacement may work together to ensure efficient and robust invasion. PMID:24778942

  13. Structural analysis of the Hasan-Robat marbles as traces of folded basement in the Sanandaj-Sirjan Zone, Iran

    Science.gov (United States)

    Nadimi, Alireza

    2015-11-01

    Cherty marbles of Hasan-Robat area, northwest of Isfahan, in the Sanandaj-Sirjan Zone of Iran preserves evidences of multiple deformational events. The Sanandaj-Sirjan Zone is the inner crystalline zone of the Zagros Orogen, which has been highly deformed and exhumed during continental collision between the Arabian Plate and Central Iran. The Hasan-Robat area is an example of the exposed Precambrian-Paleozoic basement rocks that stretched along two NW-SE-trending faults and located in the inner part of the HasanRobat positive flower strcuture. The Hasan-Robat marbles record a complex shortening and shearing history. This lead to the development of disharmonic ptygmatic folds with vertical to sub-vertical axes and some interference patterns of folding that may have been created from deformations during the Pan-African Orogeny and later phases. Based on this research, tectonic evolution of the Hasan-Robat area is interpreted as the product of three major geotectonic events that have been started after Precambrian to Quaternary: (1) old deformation phases (2) contractional movements and (3) strike-slip movements. Different sets and distributions of joints, faults and folds are confirmed with effect of several deformational stages of the area and formation of the flower structure.

  14. Geophysical prospecting for the deep geothermal structure of the Zhangzhou basin, Southeast China

    Science.gov (United States)

    Wu, Chaofeng; Liu, Shuang; Hu, Xiangyun; Wang, Guiling; Lin, Wenjing

    2017-04-01

    Zhangzhou basin located at the Southeast margins of Asian plate is one of the largest geothermal fields in Fujian province, Southeast China. High-temperature natural springs and granite rocks are widely distributed in this region and the causes of geothermal are speculated to be involved the large number of magmatic activities from Jurassic to Cretaceous periods. To investigate the deep structure of Zhangzhou basin, magnetotelluric and gravity measurements were carried out and the joint inversion of magnetotelluric and gravity data delineated the faults and the granites distributions. The inversion results also indicated the backgrounds of heat reservoirs, heat fluid paths and whole geothermal system of the Zhangzhou basin. Combining with the surface geological investigation, the geophysical inversion results revealed that the faults activities and magma intrusions are the main reasons for the formation of geothermal resources of the Zhangzhou basin. Upwelling mantle provides enormous heats to the lower crust leading to metamorphic rocks to be partially melt generating voluminous magmas. Then the magmas migration and thermal convection along the faults warm up the upper crust. So finally, the cap rocks, basements and major faults are the three favorable conditions for the formation of geothermal fields of the Zhangzhou basin.

  15. The role of basement tectonics in the control of sedimentary facies, structural patterns and salt plug emplacements in the Zagros fold belt of southwest Iran

    Science.gov (United States)

    McQuillan, Harry

    Extensive field observations over a large tract of continuous rock outcrops in the Zagros Mountain Range of southwest Iran have yielded a wealth of stratigraphic and structural detail. In the region structural anomalies are frequently associated with similar facies distribution patterns. In the eastern portion of the region emergent salt plugs of infra-Cambrian age exhibit the same alignment patterns. Such trends bear no apparent genetic relationship to the Tertiary folding responsible for the present fold belt grain of the Zagros Range but rather indicate affinity with linear basement features which are readily observable on Landsat imagery and air photographs. Superimposed on the eastern region's mode of facies trends and structure are localized variations which are directly attributed to pulses of salt diapiric activity. Thus stratigraphic data acquired from deep sections associated with salt domes can lead to erroneous overviews of regional facies distributions while anomalous dome-shaped structural features associated with elongate fold, so common to the fold belt, can only be attributed to near surface diapiric structures. The recognition of features related to basement tectonics and the realization of their implication in the control and modification of geological processes is an important adjunct to the search for hydrocarbon accumulations in the region. Indeed it can be shown that renewed movements on basement trends directly affect ooil production patterns as a consequence of the enhancement of fracture porosity and permeability in Tertiary carbonate reservoir structures. These constitute some of the world's largest oil-producing fields.

  16. Geo-electrical investigation of near surface conductive structures suitable for groundwater accumulation in a resistive crystalline basement environment: A case study of Isuada, southwestern Nigeria

    Science.gov (United States)

    Kayode, J. S.; Adelusi, A. O.; Nawawi, M. N. M.; Bawallah, M.; Olowolafe, T. S.

    2016-07-01

    This paper presents a geophysical surveying for groundwater identification in a resistive crystalline basement hard rock in Isuada area, Southwestern Nigeria. Very low frequency (VLF) electromagnetic and electrical resistivity geophysical techniques combined with well log were used to characterize the concealed near surface conductive structures suitable for groundwater accumulation. Prior to this work; little was known about the groundwater potential of this area. Qualitative and semi-quantitative interpretations of the data collected along eight traverses at 20 m spacing discovered conductive zones suspected to be fractures, faults, and cracks which were further mapped using Vertical Electrical Sounding (VES) technique. Forty VES stations were utilized using Schlumberger configurations with AB/2 varying from 1 to 100 m. Four layers i.e. the top soil, the weathered layer, the partially weathered/fractured basement and the fresh basement were delineated from the interpreted resistivity curves. The weathered layers constitute the major aquifer unit in the area and are characterized by moderately low resistivity values which ranged between about 52 Ωm and 270 Ωm while the thickness varied from 1 to 35 m. The depth to the basement and the permeable nature of the weathered layer obtained from both the borehole and the hand-dug wells was used to categorize the groundwater potential of the study area into high, medium and low ratings. The groundwater potential map revealed that about 45% of the study area falls within the low groundwater potential rating while about 10% constitutes the medium groundwater potential and the remaining 45% constitutes high groundwater potential. The low resistivity, thick overburden, and fractured bedrock constitute the aquifer units and the series of basement depressions identified from the geoelectric sections as potential conductive zones appropriate for groundwater development.

  17. A public domain model for 1D temperature and rheology construction in basement-sedimentary geothermal exploration: an application to the Spanish Central System and adjacent basins

    NARCIS (Netherlands)

    Limberger, J.; Bonte, D.; Vicente, G. de; Beekman, F.; Cloetingh, S.; Wees, J.D. van

    2017-01-01

    Brittle basement and sedimentary rocks, in particular if these are underlain by radiogenic crust, are considered a prime target for enhanced geothermal systems (EGS). They are marked by high geothermal gradients, caused by radiogenic heat production, and are well suited to be used for geothermal

  18. Seismic crustal structure between the Transylvanian Basin and the Black Sea, Romania

    Science.gov (United States)

    Hauser, F.; Raileanu, V.; Fielitz, W.; Dinu, C.; Landes, M.; Bala, A.; Prodehl, C.

    2007-02-01

    In order to study the lithospheric structure in Romania a 450 km long WNW-ESE trending seismic refraction project was carried out in August/September 2001. It runs from the Transylvanian Basin across the East Carpathian Orogen and the Vrancea seismic region to the foreland areas with the very deep Neogene Focsani Basin and the North Dobrogea Orogen on the Black Sea. A total of ten shots with charge sizes 300-1500 kg were recorded by over 700 geophones. The data quality of the experiment was variable, depending primarily on charge size but also on local geological conditions. The data interpretation indicates a multi-layered structure with variable thicknesses and velocities. The sedimentary stack comprises up to 7 layers with seismic velocities of 2.0-5.9 km/s. It reaches a maximum thickness of about 22 km within the Focsani Basin area. The sedimentary succession is composed of (1) the Carpathian nappe pile, (2) the post-collisional Neogene Transylvanian Basin, which covers the local Late Cretaceous to Paleogene Tarnava Basin, (3) the Neogene Focsani Basin in the foredeep area, which covers autochthonous Mesozoic and Palaeozoic sedimentary rocks as well as a probably Permo-Triassic graben structure of the Moesian Platform, and (4) the Palaeozoic and Mesozoic rocks of the North Dobrogea Orogen. The underlying crystalline crust shows considerable thickness variations in total as well as in its individual subdivisions, which correlate well with the Tisza-Dacia, Moesian and North Dobrogea crustal blocks. The lateral velocity structure of these blocks along the seismic line remains constant with about 6.0 km/s along the basement top and 7.0 km/s above the Moho. The Tisza-Dacia block is about 33 to 37 km thick and shows low velocity zones in its uppermost 15 km, which are presumably due to basement thrusts imbricated with sedimentary successions related to the Carpathian Orogen. The crystalline crust of Moesia does not exceed 25 km and is covered by up to 22 km of

  19. Basement of Structure, Main Power and Design Parameters of Mechanism of Removing Sections of Mechanized Sets of Knife Plane Installation

    Science.gov (United States)

    Sysoev, N. I.; Turuk, Yu V.; Kolesnichenko, I. Y.; Lugantsev, B. B.

    2017-10-01

    The reasons for the failure of the pitch stability of the knife-plane installation due to the action of extreme effort in the plane of the seam from the conveyor side on the mechanism of removing sections of mechanized sets are shown. The technique for determining this effort is presented. The constructions of the adaptive mechanisms of the removing sections of mechanized sets with the basements of catamaran type, in the constrictions of which elastic elements (rods) are used, are considered. The constructions of the mechanism of removing a section of the mechanized set with the basement of catamaran type in which the stock of the hydraulic jack is connected with the band loop through the movable rods intermediate basement with a link are worked out. The intermediate basement unloads the stock of the hydraulic jack of the moving installation from the side curving efforts, caused by the action of lateral forces in the plane of the seam on the conveyor side. It increases the reliability and efficiency of work of the knife plane mechanized complex.

  20. Mixed basin boundary structures of chaotic systems

    International Nuclear Information System (INIS)

    Rosa, E. Jr.; Ott, E.

    1999-01-01

    Motivated by recent numerical observations on a four-dimensional continuous-time dynamical system, we consider different types of basin boundary structures for chaotic systems. These general structures are essentially mixtures of the previously known types of basin boundaries where the character of the boundary assumes features of the previously known boundary types at different points arbitrarily finely interspersed in the boundary. For example, we discuss situations where an everywhere continuous boundary that is otherwise smooth and differentiable at almost every point has an embedded uncountable, zero Lebesgue measure set of points at which the boundary curve is nondifferentiable. Although the nondifferentiable set is only of zero Lebesgue measure, the curve close-quote s fractal dimension may (depending on parameters) still be greater than one. In addition, we discuss bifurcations from such a mixed boundary to a 'pure' boundary that is a fractal nowhere differentiable curve or surface and to a pure nonfractal boundary that is everywhere smooth. copyright 1999 The American Physical Society

  1. The metamorphic basement of the southern Sierra de Aconquija, Eastern Sierras Pampeanas: Provenance and tectonic setting of a Neoproterozoic back-arc basin

    Science.gov (United States)

    Cisterna, Clara Eugenia; Altenberger, Uwe; Mon, Ricardo; Günter, Christina; Gutiérrez, Antonio

    2018-03-01

    (wackes, shales, Fe-shales and minor litharenites) are characteristic for turbidity currents deposits along tectonically active region. They are also commonly associated with calcareous clays (marbles), commonly observed in the evolution of basins with slope and shelf derived carbonate turbidites. The amphibolites members are probably derived from lava-flows synchronous with the sedimentation during the basin evolution. The basin was controlled by a continental island arc possible evolving to a back-arc setting, as indicated for the mixed nature of the inferred source. The metasedimentary sequence from the Cuesta de La Chilca have petrographic, structural and strong chemical similarities, building a north-south striking belt from the north of the Sierra de Aconquija and to the south along the Sierra de Ancasti (La Majada area). The observed similarities allow to present this portion of the Eastern Sierras Pampeanas as a crustal block that records the sedimentary sequences developed along the geodynamic context of the southwestern margin of Gondwana during the Neoproterozoic and Early Palaeozoic.

  2. 3D structural model of the North Alpine Foreland Basin, Bavarian Part

    Science.gov (United States)

    Przybycin, Anna M.; Scheck-Wenderoth, Magdalena; Schneider, Michael

    2013-04-01

    The continental collision of Europe and Africa leads to the rise of the European Alps, which gave way to the formation of the North Alpine Foreland Basin, also referred to as the Molasse Basin, since the Tertiary. This typically wedge formed "foredeep" basin is filled with predominantly clastic sediments originating from erosional processes of the Alps which overly a southward dipping Mesozoic and Paleozoic succession. With our project we want to contribute to the understanding of the structure and subsequently of the thermal configuration of the Molasse Basin and its underlying deposits on a basin wide scale. We constructed a 3D structural model of the basin down to the crust-mantle-boundary, beginning with the Bavarian part. Therefore we used an approach of already existing local to midscale 2D and 3D structural models (e.g. Lüschen et al. 2006) as well as surface maps, seismic, well and gravity data. This 3D structural model resolves 5 sedimentary layers of the Mesozoic, including the geothermally utilized carbonate Malm aquifer (e.g. Birner et al. 2011), as well as the combined Paleozoic basement. Assuming isostatic equilibrium of the system a lithosphere-asthenosphere-boundary (LAB) has been calculated and compared to other published LABs of the region. Subsequently the model has been further constrained by 3D gravity modeling. The outcomes show that Cretaceous sediments are restricted to a small region in the central to eastern model area and are mostly overlain by the Tertiary Molasse sediments. The Triassic sediments occur in the northern and western part of the model area and do not continue far under the Molasse basin proper, while the Jurassic can be tracked as far south as beneath the Alps. The evaluation of the gravity indicates that the crystalline crust consists of a lighter upper crust and a denser lower crust. Our final LAB is shallowest under the Triassic subbasin, descending below the Bohemian Massif and the Molasse Basin proper and rising again

  3. Evidence for an Early Cretaceous mineralizing event above the basement/sediment unconformity in the intracratonic Paris Basin: paragenetic sequence and Sm-Nd dating of the world-class Pierre-Perthuis stratabound fluorite deposit

    Science.gov (United States)

    Gigoux, Morgane; Delpech, Guillaume; Guerrot, Catherine; Pagel, Maurice; Augé, Thierry; Négrel, Philippe; Brigaud, Benjamin

    2015-04-01

    World-class stratabound fluorite deposits are spatially associated with the basement/sediment unconformity of the intracratonic Paris Basin and the Morvan Massif in Burgundy (France). The reserves are estimated to be about 5.5 Mt of fluorite within six fluorite deposits. In this study, we aim to determine the age of the major fluorite mineralization event of the Pierre-Perthuis deposit (1.4 Mt fluorite) by a combined study of the paragenetic mineral sequence and Sm-Nd dating on fluorite crystals. Fluorite occurs as isolated cubes or filling geodes in a Triassic, silicified, dolomitic formation. Three fluorite stages associated with sphalerite, pyrite, galena, barite, and quartz have been distinguished using optical, cathodoluminescence, and scanning electron microscopes. Seven crystals of the geodic fluorite stage were analyzed for their rare earth element (REE) contents and their 147Sm/144Nd and 143Nd/144Nd isotopic compositions. The normalized REE distribution displays homogeneous bell-shaped patterns for all the geodic fluorite samples with a Mid-REE enrichment over the Light-REE and Heavy-REE. The 147Sm/144Nd varies from 0.3108 to 0.5504 and the 143Nd/144Nd from 0.512313 to 0.512518. A six-point Sm-Nd isochron defines an age of 130 ± 15 Ma (initial 143Nd/144Nd = 0.512054, MSWD = 0.21). This Sm-Nd isochron provides the first age for the stratabound fluorite sediment-hosted deposit, related to an unconformity in the Paris Basin, and highlights a major Early Cretaceous fluid circulation event mainly above the basement/sediment unconformity during a flexural deformation of the Paris Basin, which relates to the rifting of the Bay of Biscay and the formation of the Ligurian Sea in the Western Europe domain.

  4. Role of low angle normal faulting and basement thrusting on the structural architecture of the Northern Apennines (Italy)

    Science.gov (United States)

    Molli, Giancarlo; Carlini, Mirko; Vescovi, Paolo; Artoni, Andrea; Balsamo, Fabrizio; Camurri, Francesca; Clemenzi, Luca; Storti, Fabrizio; Torelli, Luigi

    2017-04-01

    The Northern Apennines of Italy are a classical site for studying fundamental issues in thrust wedges, such as ophiolite formation and emplacement, interplay between tectonics and sedimentation, role of out-of-sequence thrusting, syn-orogenic versus post-orogenic extension, along strike segmentation, etc. Accordingly, the Northern Apennines have been extensively studied since more than two centuries ago. Despite the huge amount of available data with different resolution, a 3D comprehensive regional view combining in a modern framework all available surface and subsurface information for contiguous sectors of the chain is still lacking. We performed such an attempt in the area framed between the Taro valley to the north and the northern termination of the Alpi Apuane to the south. The region includes the main morphostructural zones of the North-West Apennines from the Tyrrhenian coast West-Northwest of La Spezia, through the main topographic divide of the Apennines, to the external frontal part of the chain. The area has been investigated through a multidisciplinary approach that integrated: 1) surface geological data collected during the last two decades of structural and stratigraphic field works in the internal as well as external sectors of the chain; 2) subsurface geological data including: a) interpretation of 1200 Km of seismic reflection profiles tied to surface geology and b) analysis of 39 boreholes stratigraphies. The construction of two regional NE-SW trending cross-sections (the Levanto-Pontremoli-Parma to the North and the La Spezia-Sarzana-North Apuane-Cerreto to the South), connected by the NW-SE trending Taro River-Lunigiana Area-Alpi Apuane composite section, allowed us to illustrate (i) the role of out-of-sequence blind thrusting in the basement, (ii) the presence of low angle normal faulting and its relationships with recent to active high angle normal faulting. Both extensional and contractional systems have relevant implications for the

  5. Structure of the la VELA Offshore Basin, Western Venezuela: AN Obliquely-Opening Rift Basin Within the South America-Caribbean Strike-Slip Plate Boundary

    Science.gov (United States)

    Blanco, J. M.; Mann, P.

    2015-12-01

    Bathymetric, gravity and magnetic maps show that the east-west trend of the Cretaceous Great Arc of the Caribbean in the Leeward Antilles islands is transected by an en echelon series of obliquely-sheared rift basins that show right-lateral offsets ranging from 20 to 40 km. The basins are 75-100 km in length and 20-30 km in width and are composed of sub-parallel, oblique slip normal faults that define deep, bathymetric channels that bound the larger islands of the Leeward Antilles including Aruba, Curacao and Bonaire. A single basin of similar orientation and structure, the Urumaco basin, is present to the southwest in the Gulf of Venezuela. We mapped structures and sedimentation in the La Vela rift basin using a 3D seismic data volume recorded down to 6 seconds TWT. The basin can be mapped from the Falcon coast where it is correlative with the right-lateral Adicora fault mapped onshore, and its submarine extension. To the southeast of the 3D survey area, previous workers have mapped a 70-km-wide zone of northeast-striking, oblique, right-lateral faults, some with apparent right-lateral offsets of the coastline. On seismic data, the faults vary in dip from 45 to 60 degrees and exhibit maximum vertical offsets of 600 m. The La Vela and other obliquely-opening rifts accommodate right-lateral shear with linkages to intervening, east-west-striking right-lateral faults like the Adicora. The zone of oblique rifts is restricted to the trend of the Great Arc of the Caribbean and may reflect the susceptiblity of this granitic basement to active shearing. The age of onset for the basins known from previous studies on the Leeward Antilles is early Miocene. As most of these faults occur offshore their potential to generate damaging earthquakes in the densely populated Leeward Antilles is not known.

  6. cDNA cloning of the basement membrane chondroitin sulfate proteoglycan core protein, bamacan: a five domain structure including coiled-coil motifs

    DEFF Research Database (Denmark)

    Wu, R R; Couchman, J R

    1997-01-01

    obtained cDNA clones encoding the entire bamacan core protein of Mr = 138 kD, which reveal a five domain, head-rod-tail configuration. The head and tail are potentially globular, while the central large rod probably forms coiled-coil structures, with one large central and several very short interruptions....../translation product from a full-length bamacan cDNA. The unusual structure of this proteoglycan is indicative of specific functional roles in basement membrane physiology, commensurate with its distinct expression in development and changes in disease models....

  7. Influence of lithosphere and basement properties on the stretching factor and development of extensional faults across the Otway Basin, southeast Australia

    NARCIS (Netherlands)

    Kharazizadeh, N.; Schellart, W. P.; Duarte, J.C.; Hall, M.

    2017-01-01

    The NW-SE striking Otway Basin in southeastern Australia is part of the continental rift system that formed during the separation of Australia from Antarctica. The development of this sedimentary basin occurred in two phases of Late Jurassic-Early Cretaceous and Late Cretaceous rifting. The

  8. Effects of irregular basement structure on the geometry and emplacement of frontal thrusts and duplexes in the Quebec Appalachians: Interpretations from well and seismic reflection data

    Science.gov (United States)

    Konstantinovskaya, E.; Malo, M.; Badina, F.

    2014-12-01

    Irregular basement geometry may affect thrust propagation in foreland fold-thrust belts creating a perturbation in structural continuity of hydrocarbon fields. Here we investigate how the irregular pattern of normal faults, along with the presence of uplifts and transverse faults in the Grenvillian basement has influenced the geometry and emplacement of frontal thrusts and duplexes in the parautochthonous domain of the southern Quebec Appalachians during the middle-late Ordovician Taconian orogeny. Integration of data from surface geology, wells, and 2D and 3D seismic reflection surveys into a regional-scale structural model is used to reconstruct the 3D geometry and emplacement history of one- and two-horse duplexes in the Joly-Saint-Flavien gas storage area. The normal hinterland to foreland sequence of thrusting in this area is complicated by the differential emplacement of tectonic slices along strike of the orogenic front, starting in the SW and developing subsequently to the NE within each structural level. The shortening related to duplex emplacement decreases laterally over the distance of 20 km from - 49% in the SW (Joly area) to - 31% in the NE (Saint-Flavien area). Duplex emplacement resulted from the differential forward propagation, deflexion and vertical-axis rotation of the roof thrust (Logan's Line), which, in turn, has been induced by the presence of frontal uplift and transverse faults in the basement. The structural-lithological analysis of tectonic slices and restoration of their initial location allows us to consider the lower slice of the Joly duplex as a structural trap comparable to the fractured reservoir in lower Ordovician dolomites of the Saint-Flavien duplex.

  9. Depth-To-Basement Mapping Using Fractal Technique: Application ...

    African Journals Online (AJOL)

    ... and can thus be obtained at source level. Application to aeromagnetic data from the Chad basin north eastern Nigeria produced a basement relief which range from depths of 2.47 km to 5.40 km with an average of 3.92 +- 0.66 km. Keywords: Fractal, depth, basement, spectra, aeromagnetic. Nigerian Journal of Physics Vol ...

  10. Application of high resolution aeromagnetic data for basement topography mapping of Siluko and environs, southwestern Nigeria

    Science.gov (United States)

    Osinowo, Olawale O.; Akanji, Adesoji O.; Olayinka, Abel I.

    2014-11-01

    The discovery of hydrocarbon in commercial quantity in the Niger Delta, southern Nigeria, has since the early fifties shifted the attention of exploration/active geological studies from the Dahomey basin and the adjacent basement terrain in south-western Nigeria towards the south and this has left some gaps in information required for the discovery and exploitation of the economic potential of the region. This study mapped the Siluko transition zone in south-western Nigeria in terms of structures, geometry and basement topography with the object of providing requisite geological information that will engender interest in the exploration and exploitation of the numerous economic potentials of south-western part of Nigeria. Acquired high resolution aeromagnetic data were filtered, processed and enhanced, the resultant data were subjected to qualitative and quantitative magnetic interpretation, depth weighting analyses and modelling to generate the subsurface basement topography across the study area. The obtained results indicate regions of high and low magnetic anomalies with residual magnetic intensity values ranging from -100.8 nT to 100.9 nT. Euler Deconvolution indicates generally undulating basement topography with depth range of 125-1812 m. The basement relief is generally gentle and flat lying within the basement terrain with depth ranging from 125 to 500 m. However the sedimentary terrain is undulating and generally steeps south, down the basin with depth range of 300-1812 m. A basement topography model of the magnetic data constrained by Euler solutions correlate positively with the geology of the study area and indicates a generally increasing sedimentary deposits' thickness southward toward the western part of Dahomey basin. The revealed basement topography and structures as well as the delineated direction of continuous increase in thickness of sedimentary deposit provide insight to the controlling factor responsible for tar sand deposit and bitumen

  11. Deep Structure and Subsidence History of Parnaíba Cratonic Basin, NE Brazil

    Science.gov (United States)

    Rodríguez Tribaldos, Verónica; White, Nicky; Coelho, Diogo; Julià, Jordi

    2017-04-01

    Cratonic sedimentary basins constitute some of the largest sedimentary basins on Earth. They are typically underlain by thick (i.e. 200 km) lithosphere and are characterized by slow, punctuated subsidence that occurs over hundreds of millions of years. Their stratigraphic records mainly consist of sequences of continental and shallow marine sedimentary rocks bounded by basin-wide erosional unconformities. Despite the importance of these basins, their origin and evolution remain poorly understood, mainly due to scarcity of well-constrained geological and geophysical data. In order to address this problem, an integrative study of the Parnaíba Cratonic basin in NE Brazil has been carried out within the framework of a multidisciplinary investigation. Here, we combine the analysis of a 1400 km long deep seismic reflection profile that crosses the basin, teleseismic earthquakes recorded by 12 broadband and 10 short-period, 3 component seismometers, 25 ancillary seismic reflection profiles, and 46 wells distributed across the basin. Our main goal is to constrain the basin's subsidence history in the context of its deep crustal structure and sedimentary architecture. Joint inversion of receiver functions and Rayleigh wave group dispersion measurements has been used to calculate 1D shear wave velocity models for crust and upper mantle beneath each seismic station. Combined interpretation of these velocity profiles and the deep seismic reflection profile has been carried out. Our results suggest Moho depths of approximately 35 km and 38 km beneath Precambrian basement east and west of the Parnaíba basin, respectively. In contrast, the Moho occurs at approximately 39 km beneath the city of Teresina, located on the eastern region of the basin, and at depths between 40 km and 42 km beneath the central and western areas of the basin. These results are combined to construct a sub-surface model underneath Parnaíba, and gravity modeling is used to test its validity. Average

  12. Mesozoic Crustal Thickening of the Longmenshan Belt (NE Tibet, China) by Imbrication of Basement Slices: Insights From Structural Analysis, Petrofabric and Magnetic Fabric Studies, and Gravity Modeling

    Science.gov (United States)

    Xue, Zhenhua; Martelet, Guillaume; Lin, Wei; Faure, Michel; Chen, Yan; Wei, Wei; Li, Shuangjian; Wang, Qingchen

    2017-12-01

    This work first presents field structural analysis, anisotropy of magnetic susceptibility (AMS) measurements, and kinematic and microstructural studies on the Neoproterozoic Pengguan complex located in the middle segment of the Longmenshan thrust belt (LMTB), NE Tibet. These investigations indicate that the Pengguan complex is a heterogeneous unit with a ductilely deformed NW domain and an undeformed SE domain, rather than a single homogeneous body as previously thought. The NW part of the Pengguan complex is constrained by top-to-the-NW shearing along its NW boundary and top-to-the-SE shearing along its SE boundary, where it imbricates and overrides the SE domain. Two orogen-perpendicular gravity models not only support the imbricated shape of the Pengguan complex but also reveal an imbrication of high-density material hidden below the Paleozoic rocks on the west of the LMTB. Regionally, this suggests a basement-slice-imbricated structure that developed along the margin of the Yangtze Block, as shown by the regional gravity anomaly map, together with the published nearby seismic profile and the distribution of orogen-parallel Neoproterozoic complexes. Integrating the previously published ages of the NW normal faulting and of the SE directed thrusting, the locally fast exhumation rate, and the lithological characteristics of the sediments in the LMTB front, we interpret the basement-slice-imbricated structure as the result of southeastward thrusting of the basement slices during the Late Jurassic-Early Cretaceous. This architecture makes a significant contribution to the crustal thickening of the LMTB during the Mesozoic, and therefore, the Cenozoic thickening of the Longmenshan belt might be less important than often suggested.

  13. ROCK1-directed basement membrane positioning coordinates epithelial tissue polarity.

    Science.gov (United States)

    Daley, William P; Gervais, Elise M; Centanni, Samuel W; Gulfo, Kathryn M; Nelson, Deirdre A; Larsen, Melinda

    2012-01-01

    The basement membrane is crucial for epithelial tissue organization and function. However, the mechanisms by which basement membrane is restricted to the basal periphery of epithelial tissues and the basement membrane-mediated signals that regulate coordinated tissue organization are not well defined. Here, we report that Rho kinase (ROCK) controls coordinated tissue organization by restricting basement membrane to the epithelial basal periphery in developing mouse submandibular salivary glands, and that ROCK inhibition results in accumulation of ectopic basement membrane throughout the epithelial compartment. ROCK-regulated restriction of PAR-1b (MARK2) localization in the outer basal epithelial cell layer is required for basement membrane positioning at the tissue periphery. PAR-1b is specifically required for basement membrane deposition, as inhibition of PAR-1b kinase activity prevents basement membrane deposition and disrupts overall tissue organization, and suppression of PAR-1b together with ROCK inhibition prevents interior accumulations of basement membrane. Conversely, ectopic overexpression of wild-type PAR-1b results in ectopic interior basement membrane deposition. Significantly, culture of salivary epithelial cells on exogenous basement membrane rescues epithelial organization in the presence of ROCK1 or PAR-1b inhibition, and this basement membrane-mediated rescue requires functional integrin β1 to maintain epithelial cell-cell adhesions. Taken together, these studies indicate that ROCK1/PAR-1b-dependent regulation of basement membrane placement is required for the coordination of tissue polarity and the elaboration of tissue structure in the developing submandibular salivary gland.

  14. A preliminary investigation of the structure of southern Yucca Flat, Massachusetts Mountain, and CP basin, Nevada Test Site, Nevada, based on geophysical modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Geoffrey A. Phelps; Leigh Justet; Barry C. Moring, and Carter W. Roberts

    2006-03-17

    New gravity and magnetic data collected in the vicinity of Massachusetts Mountain and CP basin (Nevada Test Site, NV) provides a more complex view of the structural relationships present in the vicinity of CP basin than previous geologic models, helps define the position and extent of structures in southern Yucca Flat and CP basin, and better constrains the configuration of the basement structure separating CP basin and Frenchman Flat. The density and gravity modeling indicates that CP basin is a shallow, oval-shaped basin which trends north-northeast and contains ~800 m of basin-filling rocks and sediment at its deepest point in the northeast. CP basin is separated from the deeper Frenchman Flat basin by a subsurface ridge that may represent a Tertiary erosion surface at the top of the Paleozoic strata. The magnetic modeling indicates that the Cane Spring fault appears to merge with faults in northwest Massachusetts Mountain, rather than cut through to Yucca Flat basin and that the basin is downed-dropped relative to Massachusetts Mountain. The magnetic modeling indicates volcanic units within Yucca Flat basin are down-dropped on the west and supports the interpretations of Phelps and KcKee (1999). The magnetic data indicate that the only faults that appear to be through-going from Yucca Flat into either Frenchman Flat or CP basin are the faults that bound the CP hogback. In general, the north-trending faults present along the length of Yucca Flat bend, merge, and disappear before reaching CP hogback and Massachusetts Mountain or French Peak.

  15. Magnetotelluric inversion for depth-to-basement estimation

    DEFF Research Database (Denmark)

    Cai, Hongzhu; Zhdanov, Michael

    2015-01-01

    The magnetotelluric (MT) method can be effectively applied for depth-to-basement estimation, because there exists a strong contrast in resistivity between a conductive sedimentary basin and a resistive crystalline basement. Conventional inversions of MT data are usually aimed at determining...... the volumetric distribution of the conductivity within the inversion domain. By the nature of the MT method, the recovered distribution of the subsurface conductivity is typically diffusive, which makes it difficult to select the sediment-basement interface. This paper develops a novel approach to 3D MT...... inversion for the depth-to-basement estimate. The key to this approach is selection of the model parameterization with the depth to basement being the major unknown parameter. In order to estimate the depth to the basement, the inversion algorithm recovers both the thickness and the conductivities...

  16. Field experiment for investigation of very shallow basement structure by micro-gravity survey; Microgravity tansa no gokusenbu kiban chosa eno tekiyo jikken

    Energy Technology Data Exchange (ETDEWEB)

    Oshita, K.; Nozaki, K. [OYO Corp., Tokyo (Japan)

    1997-10-22

    This paper illustrates the field experiment results in which micro-gravity survey was applied to investigation of very shallow basement structure between a few m and 10 m. Its applicability was discussed. In principle, the micro-gravity survey was conducted at the measuring points in a grid with 20 m pitch. Measuring points of 174 were used. The gravity system used for the measurements is an automatic gravimeter CG-3M made by the Scintrex. Survey results of P-wave reflection method conducted at the site using a vibrator focus were used as control data of micro-gravity survey. Consequently, change in the thickness of surface layer (earth filling) shallower than the depth of -10 m could be grasped as a plane. It was found that the micro-gravity survey is a useful method for the investigation of very shallow basement structure. Survey results by the reflection method could contribute to the determination of trend face at filtration and construction of density model as well as the geologic interpretation of gravity anomaly. As a result, reliability of micro-gravity survey and reflection method could be enhanced, mutually. 3 refs., 8 figs.

  17. Structure of the crust and upper mantle beneath the Western Canada Sedimentary Basin: An integrated geophysical approach

    Science.gov (United States)

    Hope, Jacqueline A.

    A vast area of the Precambrian craton of Laurentia lies buried beneath Phanerozoic rocks of the Western Canada Sedimentary Basin (WCSB). The lithospheric evolution of this crystalline basement and the stratigraphic architecture of the overlying sedimentary rocks have been investigated using geophysical techniques. A 1400-km reflection-seismic profile constructed from LITHOPROBE lines was used for regional investigation of basin structure and the nature of the basement-cover contact. Instantaneous attribute analysis of the top-of-basement reflection reveals domain-dependent properties. The seismic data also show that normal faulting in the basin, widely separated in both space and time, displays previously undocumented characteristics of extensional forced-folding. Previous workers have used gravity and magnetic data as the basis for qualitative subdivision of the crystalline basement into tectonic domains. Here, crustal structure in the vicinity of 6 prominent gravity and magnetic anomalies were investigated in a quantitative fashion by numerical simulation. Independent constraints from seismic and magnetotelluric data were used to mitigate the inherent non-uniqueness of the potential-field interpretations. In the case of the Vulcan Structure, a Paleoproterozoic collision zone in southern Alberta, significant remanent magnetization was invoked to simplify the interpretation of paired positive-negative magnetic anomalies that had been interpreted previously as separate domains. If correct, this interpretation challenges the almost universally held assumption that remanent magnetization is negligible in Precambrian terranes. Elsewhere, numerical modelling shows that previous seismic interpretations of a 10-km offset in the Moho across a splay of the Snowbird tectonic zone is consistent with, but not required by, the gravity signature of this feature. The Great Slave Lake shear zone is a conspicuous 1300-km linear potential-field anomaly that has been interpreted as

  18. Stratigraphic and structural revision of the Upper Mesozoic succession of the Dadès valley, eastern Ouarzazate Basin (Morocco)

    Science.gov (United States)

    Benvenuti, Marco; Moratti, Giovanna; Algouti, Ahmed

    2017-11-01

    The paper presents a stratigraphic and structural revision of the Late Mesozoic succession exposed in the Dadès River valley (eastern Ouarzazate Basin), at the southern front of the Central High Atlas. Facies analysis, recognition of different rank erosional, angular and progressive unconformities and new paleontological data, allowed a subdivision into five units of four formations formerly ascribed to the Late Cretaceous. The local stratigraphy is tentatively correlated with the Middle Jurassic-Upper Cretaceous successions exposed in different sectors of the Central High Atlas. Integrated structural and stratigraphic data led to infer a predominant tectonically-driven development of these units. The local tectono-depositional scenario suggests since the Middle-Late Jurassic the occurrence of southward-directed fluvial systems sourced from an uplifting basement high in the axial portion of the Central High Atlas and paired to an incipient foreland basin confined by the Anti-Atlasic ranges. Crustal shortening may have caused an early tectonic inversion of the basement high progressively propagated to the south with subsequent deformation of the sedimentary cover.

  19. Ophiolitic basement to the Great Valley forearc basin, California, from seismic and gravity data: Implications for crustal growth at the North American continental margin

    Science.gov (United States)

    Godfrey, N.J.; Beaudoin, B.C.; Klemperer, S.L.; Levander, A.; Luetgert, J.; Meltzer, A.; Mooney, W.; Tréhu, A.

    1997-01-01

    The nature of the Great Valley basement, whether oceanic or continental, has long been a source of controversy. A velocity model (derived from a 200-km-long east-west reflection-refraction profile collected south of the Mendocino triple junction, northern California, in 1993), further constrained by density and magnetic models, reveals an ophiolite underlying the Great Valley (Great Valley ophiolite), which in turn is underlain by a westward extension of lower-density continental crust (Sierran affinity material). We used an integrated modeling philosophy, first modeling the seismic-refraction data to obtain a final velocity model, and then modeling the long-wavelength features of the gravity data to obtain a final density model that is constrained in the upper crust by our velocity model. The crustal section of Great Valley ophiolite is 7-8 km thick, and the Great Valley ophiolite relict oceanic Moho is at 11-16 km depth. The Great Valley ophiolite does not extend west beneath the Coast Ranges, but only as far as the western margin of the Great Valley, where the 5-7-km-thick Great Valley ophiolite mantle section dips west into the present-day mantle. There are 16-18 km of lower-density Sierran affinity material beneath the Great Valley ophiolite mantle section, such that a second, deeper, "present-day" continental Moho is at about 34 km depth. At mid-crustal depths, the boundary between the eastern extent of the Great Valley ophiolite and the western extent of Sierran affinity material is a near-vertical velocity and density discontinuity about 80 km east of the western margin of the Great Valley. Our model has important implications for crustal growth at the North American continental margin. We suggest that a thick ophiolite sequence was obducted onto continental material, probably during the Jurassic Nevadan orogeny, so that the Great Valley basement is oceanic crust above oceanic mantle vertically stacked above continental crust and continental mantle.

  20. The structural elements and tectonics of the Lake Van basin (Eastern Anatolia) from multi-channel seismic reflection profiles

    Science.gov (United States)

    Toker, Mustafa; Sengor, A. M. Celal; Demirel Schluter, Filiz; Demirbag, Emin; Cukur, Deniz; Imren, Caner; Niessen, Frank; PaleoVan-Working Group

    2017-05-01

    This study analyzed multi-channel seismic reflection data from Lake Van, Eastern Anatolia, to provide key information on the structural elements, deformational patterns and overall tectonic structure of the Lake Van basin. The seismic data reveal three subbasins (the Tatvan, northern and Ahlat subbasins) separated by structural ridges (the northern and Ahlat ridges). The Tatvan basin is a tilted wedge-block in the west, it is a relatively undeformed and flat-lying deep basin, forming a typical example of strike-slip sedimentation. Seismic sections reveal that the deeper sedimentary sections of the Tatvan basin are locally folded, gently in the south and more intensely further north, suggesting a probable gravitational "wedge-block" instability, oblique to the northern margin. The northern subbasin, bounded by normal oblique faults, forms a basin-margin graben structure that is elongated in a northeast-southwest direction. The east-west trending Ahlat ridge forms a fault-wedged sedimentary ridge and appears to offset by reverse oblique faults forming as a push-up rhomb horst structure. The Ahlat subbasin is a fault-wedged trough fill that is elongated in the west-east direction and appears as a horst-foot graben formed by the normal oblique faults. The northeast-southwest directed northern ridge is a faulted crestal terrace of a sublacustrine basement block. Its step-like morphology, in response to the downfaulting of the Tatvan basin, as well as its backthrusted appearance, indicates the normal oblique nature of the bounding faults. The lacustrine shelf and slope show distinctive stratigraphic features; progradational deltas, submerged fluvial channels, distorted and collapsed beddings and soft sediment deformation structures, characterizing a highly unstable nature of shelf caused by strong oblique faulting and related earthquakes. The faulting caused uplift of the Çarpanak spur zone, together with the northeastern Erek delta, deformation of deltaic structures

  1. Internal structure of the Supragetic Unit basement in the Serbian Carpathians and its significance for the late Early Cretaceous nappe-stacking

    Directory of Open Access Journals (Sweden)

    Krstekanić Nemanja

    2017-01-01

    Full Text Available Fault-related folds and hanging-wall structures reflect the geometry of the main thrusts in foldthrust belts. The results of the structural analysis of the Supragetic Unit metamorphic basement in eastern Serbia at map-, outcrop- and thin-section scale, and its importance for the late Early Cretaceous nappe-stacking are presented in this paper. The Supragetic Unit metamorphic basement includes various volcano-sedimentary rocks of Ordovician-Silurian protolith age. They were metamorphosed to the low greenschist facies with temperatures reaching 300-350°C and pressure reaching 0.3-0.5 GPa. The microscale studies show that quartz and albite demonstrate dominantly bulging and locally subgrain rotation recrystallisation, while chlorite, sericite and muscovite define spaced to continuous foliation recognised both at the outcrop- and the thin-section-scale. The statistical analysis based on the available map data shows low- to high-angle west-dipping foliation which is interpreted as an indicator of flat-ramp geometry of the Supragetic thrust, rather than east-vergent tight to isoclinal folding. At the thin-section scale ductile to semi-ductile C’-S structures indicate top to ESE thrusting. Subsequent kinking, recognised both at the outcrop- and the thin-section-scale, deform the older foliation. Those kink bands are the result of WNW-ESE to NW-SE compression and could represent the later stage of a continuous deformation event during which C’-S structures were formed. The youngest, brittle deformation is represented by subvertical joints with no offset recognised in thin-sections. The structural characteristics of the Supragetic Unit low-grade metamorphic basement in the studied areas, combined with tectonothermal events recognised elsewhere in Dacia mega-unit, could imply a possible initiation of the late Early Cretaceous nappe-stacking in the ductile to semi-ductile/semi-brittle domain. [Project of the Serbian Ministry of Education, Science and

  2. Tectonic constraints on the development and individualization of the intermontane Ronda basin (external Betics, southern Spain): a structural and geomorphologic approach.

    Science.gov (United States)

    Jiménez-Bonilla, Alejandro; Balanyá, Juan Carlos; Expósito, Inmaculada; Díaz-Azpiroz, Manuel; Barcos, Leticia

    2014-05-01

    As a result of progressive shortening and orogenic wedge thickening, marine foreland basins tend to emerge and divide. We have analyzed possible recent tectonic activity within the late evolution stage of the Ronda basin, an intermontane basin located in the external wedge of the Gibraltar Arc, formerly connected with the Betic foreland basin and infilled by marine Upper-Miocene sediments. We analyze (1) the structures responsible for the basinward relief drop along the arc strike and the different topography of their boundaries; (2) qualitative and quantitative geomorphologic indices to asses which structures could present recent activity; and 3) the structures causing the division of the former Betic foreland basin and the isolation of the Ronda basin. Within the deformational history of the Ronda basin, late structures that control high topographic gradients and generate remarkable fault scarps group into three main types: (a) Extensional structures represented by NW-SE striking normal faults, clustered close to the current SW and NE boundaries of the basin. They usually dip towards the basin and their vertical displacement is maximum up to 1,5 km. These structures partially affect the basal unconformity of the Upper Miocene basin infill and are scarcely developed inside the basin infill. (b) Shortening structures developed both in the basin infill and in the outcropping basement near the Northeastern and Southwestern basin boundaries. They are represented by NE-SW directed plurikilometric box-folds and reverse faults, responsible for the alternation of sierras (altitudes 1000-1500 m) and valleys. (c) Strike-slip dominated structural associations where WSW-ENE lateral faults combined with folds and normal and reverse faults defined a NE-SW directed deformation band constituting the NW basin boundary. This band includes some sierras up to 1.100 m. Regarding the relief of the Ronda basin area, the abrupt slopes of the outcropping basement (heights between 500

  3. A model of basement structure from magnetic anomalies of the Bombay High oil-field west of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, D.G.

    "--"~'~ - "~" FAULT u NO0 7qO0- C LOS U RE i ( After Sahay. 1978) + DRY HOLE DES AREA N kilometers ' OIL WELL • DES IA 1 •, 7~:oo'E , 71-3o' I , 9"~O'E (a) Fig.2. a. Seismic contour map of the Bombay offshore basin and the Bombay High. Contour interval 200 m...

  4. Basement inheritance and salt tectonics in the SE Barents Sea: Insights from new potential field data

    Science.gov (United States)

    Gernigon, L.; Broenner, M.; Dumais, M. A.; Gradmann, S.; Grønlie, A.; Nasuti, A.; Roberts, D.

    2017-12-01

    The tectonic evolution of the former `grey zone' between Russia and Norway has so far remained poorly constrained due to a lack of geophysical data. In 2014, we carried out a new aeromagnetic survey (BASAR-14) in the southern part of the new Norwegian offshore territory. Caledonian and Timanian structures, highlighted by the new potential field data, dominate the basement patterns and have exerted a strong influence on the structure and development of the overlying basins and basement highs. Clearly associated with NW-SE-oriented Timanian trends, the Tiddlybanken Basin represents an atypical sag basin that developed at the southern edge of the Fedynsky High. Regional extension and rapid sedimentation initiated the salt tectonics in the Barents Sea in the Early Triassic. Some of the pillows became diapiric during the Early Triassic and rejuvenated during subsequent Jurassic-Tertiary episodes of regional extension and/or compression. At present, quite a few large diapiric salt domes along the Nordkapp and Tiddlybanken basins are relatively shallow, locally reaching the seabed and thus show a clear bathymetric and magnetic signature. Quantitative modelling along 2D seismic transects was also carried out to constrain the structural and basement composition of the study area. The predominant NE-SW Mesozoic trend of the Nordkapp Basin represents a major crustal hinge zone between the Finnmark Platform, poorly affected by major crustal deformation, and the Bjarmeland Platform where Late Palaeozoic rifting controlled the widespread accumulation of salt deposits in Late Carboniferous-Early Permian time. The entire structure and segmentation of the Nordkapp Basin have been influenced by the inherited basement configuration highlighted by the new aeromagnetic data. Both the Nordkapp and the Tiddlybanken basins appear to lie at the edge of a peculiar thick and rigid crustal feature that coincides with a highly magnetic region. The abrupt termination of the eastern Nordkapp

  5. Origins of streamflow in a crystalline basement catchment in a sub-humid Sudanian zone: The Donga basin (Benin, West Africa): Inter-annual variability of water budget

    Science.gov (United States)

    Séguis, L.; Kamagaté, B.; Favreau, G.; Descloitres, M.; Seidel, J.-L.; Galle, S.; Peugeot, C.; Gosset, M.; Le Barbé, L.; Malinur, F.; Van Exter, S.; Arjounin, M.; Boubkraoui, S.; Wubda, M.

    2011-05-01

    basement, for example, the upper courses of several major West African rivers (Senegal, Niger, Bani, and Volta).

  6. Gravity-driven structures and rift basin evolution: Rio Muni Basin, offshore equatorial West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.P. [Univ. of Birmingham (United Kingdom)

    1995-08-01

    Offshore Equatorial Guinea, west Africa, gravity-driven nappes, more than 1 km thick and 15 km from head to toe, provide key evidence in reconstructing the late synrift: evolution of this part of the South Atlantic margin basin system. Furthermore, Aptian-Cenomanian carbonate and clastic rocks in the nappes` allochthonous hanging walls are attracting interest as a new exploration play in west Africa. The nappes exhibit a range of geometries that suggest they share many of the same deformation processes as thin-skin thrust and linked extensional fault systems. Not only are these structures significant in their own right, representing a rare example of gravity tectonics in the virtual absence of major halokinesis, but their presence may record an other-wise undetectable process active during the transition from a rift basin to a passive continental margin. A review of Equatorial Guinea in its pre-Atlantic configuration, alongside neighboring basins in Brazil (the Sergipe-Alagoas basin) and Gabon, suggests that gravity gliding was sustained by a relatively steep, westward paleoslope promoted by east-ward offset of the locus of thermal uplift from the rift basin (i.e., a simple shear model of basin formation). In contrast to gravity-driven structures in most postrift settings, the Equatorial Guinea nappes developed at the close of the Aptian-Albian synrift episode in response to a growing bathymetric deep caused by rapid subsidence outpacing restricted sedimentation.

  7. Relationship between deep structure and oil-gas in the eastern Tarim Basin

    Science.gov (United States)

    Yu, Changqing; Qu, Chen; Han, Jianguang

    2017-04-01

    The Tarim Basin is a large composite superimposed basin which developed in the Presinian continental basement. It is an important area for oil and gas replacement in China. In the eastern part of Tarim Basin, the exploration and research degree is very low and less system, especially in the study of tectonic evolution and physical property change. Basing on the study of geophysics, drilling and regional geological data in this area, analysis of comprehensive geophysical, geological and geophysical analysis comparison are lunched by new methods and new technology of geophysical exploration. Fault, tectonic evolution and change of deep character in the eastern Tarim Basin are analyzed in system. Through in-depth study and understanding of the deep structure and physical changes of the eastern region, we obtain the fault characteristics in the study area and the deep structure and physical change maps to better guide the oil and gas exploration in this area. The east area is located in the eastern Tarim Basin, west from the Garr Man depression, Well Kunan 1 - Well Gucheng 4 line to the East, north to Kuruketage uplift group near Qunke 1 wells, south to Cherchen fault zone, east to Lop Nor depression, an area of about 9 * 104 square kilometres, Including the East of Garr Man sag, Yingjisu depression, Kongquehe slope, Tadong low uplift and the Lop Nor uplift, five two grade tectonic units. The east area of Tarim is belonging to Tarim plate. It changes with the evolution of the Tarim plate. The Tarim plate is closely related to the collision between the Yining - the Junggar plate, the Siberia plate and the southern Qiangtang - the central Kunlun plate. Therefore, it creates a complex tectonic pattern in the eastern Tarim basin. Earth electromagnetic, gravity, deep seismic and other geophysical data are processed by a new generation of geophysical information theory and method, including multi-scale inversion of potential field inversion (Hou and Yang, 2011), 3D

  8. Orphan Basin crustal structure from a dense wide-angle seismic profile - Tomographic inversion

    Science.gov (United States)

    Watremez, Louise; Lau, K. W. Helen; Nedimović, Mladen R.; Louden, Keith E.; Karner, Garry D.

    2014-05-01

    across the basin. In particular, we observe (1) a zone of extreme thinning, where the crust is thinner than 7 km; (2) basement highs and lows highlighting the blocks that accommodate the crustal thinning; (3) a central block that is thicker compared to the rest of the basin; (4) lower crustal thinning that is highly variable, which suggests a ductile deformation in the lower crust and an extensional discrepancy between the upper and lower crust (DDS); and (5) no evidence for upper-mantle serpentinization under the ultra-thinned crust. Furthermore, we show the importance of structural inheritance in rifting of the Avalon crust. Thus, we suggest that Orphan Basin is the result of rifting of a non-homogeneous Avalon terrane where the lower crust is primarily ductile.

  9. Colorado Basin Structure and Rifting, Argentine passive margin

    Science.gov (United States)

    Autin, Julia; Scheck-Wenderoth, Magdalena; Loegering, Markus; Anka, Zahie; Vallejo, Eduardo; Rodriguez, Jorge; Marchal, Denis; Reichert, Christian; di Primio, Rolando

    2010-05-01

    The Argentine margin presents a strong segmentation with considerable strike-slip movements along the fracture zones. We focus on the volcanic segment (between the Salado and Colorado transfer zones), which is characterized by seaward dipping reflectors (SDR) all along the ocean-continent transition [e.g. Franke et al., 2006; Gladczenko et al., 1997; Hinz et al., 1999]. The segment is structured by E-W trending basins, which differs from the South African margin basins and cannot be explained by classical models of rifting. Thus the study of the relationship between the basins and the Argentine margin itself will allow the understanding of their contemporary development. Moreover the comparison of the conjugate margins suggests a particular evolution of rifting and break-up. We firstly focus on the Colorado Basin, which is thought to be the conjugate of the well studied Orange Basin [Hirsch et al., 2009] at the South African margin [e.g. Franke et al., 2006]. This work presents results of a combined approach using seismic interpretation and structural, isostatic and thermal modelling highlighting the structure of the crust. The seismic interpretation shows two rift-related discordances: one intra syn-rift and the break-up unconformity. The overlying sediments of the sag phase are less deformed (no sedimentary wedges) and accumulated before the generation of oceanic crust. The axis of the Colorado Basin trends E-W in the western part, where the deepest pre-rift series are preserved. In contrast, the basin axis turns to a NW-SE direction in its eastern part, where mainly post-rift sediments accumulated. The most distal part reaches the margin slope and opens into the oceanic basin. The general basin direction is almost orthogonal to the present-day margin trend. The most frequent hypothesis explaining this geometry is that the Colorado Basin is an aborted rift resulting from a previous RRR triple junction [e.g. Franke et al., 2002]. The structural interpretation

  10. Structure and dynamics of basin forested wetlands in North America

    International Nuclear Information System (INIS)

    Brown, S.

    1990-01-01

    Freshwater basin wetlands are found in depressions of various depths, generally in areas where precipitation exceeds evapotranspiration or where the depression intersects the water table creating groundwater seeps or springs. Forested basins are those that contain woody vegetation with the potential for reaching tree stature; they do not include woody shrub wetlands. In North America these areas are mainly in the central and eastern region. Pertinent information and reviews on the distribution, floristic composition, structure and dynamics of basin forested wetlands are summarized. The major emphasis is on freshwater wetlands, but data for saltwater wetlands mainly from Florida and tropical America are included. The external factors affecting basin wetlands or the important components of a wetlands energy signature are described as well as the distribution and floristic composition of representative basin wetlands. Sections on structural characteristics, organic matter dynamics, and nutrient cycling comprise the bulk of quantitative information. The effects of disturbances, both natural and human induced, with varying degrees of impact depending upon the intensity and on the part of the ecosystem to which the stressor is applied are evaluated. Examples of stressors in basin wetlands include water impoundment, water diversion, thermal stress from hot water, sedimentation, addition of toxic substances, addition of wastewater, oil spills, and harvesting. 86 refs., 5 figs., 11 tabs

  11. The Baltic Basin: structure, properties of reservoir rocks, and capacity for geological storage of CO2

    Directory of Open Access Journals (Sweden)

    Vaher, Rein

    2009-12-01

    Full Text Available Baltic countries are located in the limits of the Baltic sedimentary basin, a 700 km long and 500 km wide synclinal structure. The axis of the syneclise plunges to the southwest. In Poland the Precambrian basement occurs at a depth of 5 km. The Baltic Basin includes the Neoproterozoic Ediacaran (Vendian at the base and all Phanerozoic systems. Two aquifers, the lower Devonian and Cambrian reservoirs, meet the basic requirements for CO2 storage. The porosity and permeability of sandstone decrease with depth. The average porosity of Cambrian sandstone at depths of 80–800, 800–1800, and 1800–2300 m is 18.6, 14.2, and 5.5%, respectively. The average permeability is, respectively, 311, 251, and 12 mD. Devonian sandstone has an average porosity of 26% and permeability in the range of 0.5–2 D. Prospective Cambrian structural traps occur only in Latvia. The 16 largest ones have CO2 storage capacity in the range of 2–74 Mt, with total capacity exceeding 400 Mt. The structural trapping is not an option for Lithuania as the uplifts there are too small. Another option is utilization of CO2 for enhanced oil recovery (EOR. The estimated total EOR net volume of CO2 (part of CO2 remaining in the formation in Lithuania is 5.6 Mt. Solubility and mineral trapping are a long-term option. The calculated total solubility trapping capacity of the Cambrian reservoir is as high as 11 Gt of CO2 within the area of the supercritical state of carbon dioxide.

  12. Seismic stratigraphy and structure of the Chukchi Borderland: implications for the opening of the Canada Basin

    Science.gov (United States)

    Ilhan, I.; Coakley, B.

    2015-12-01

    Interpretation of seismic reflection data from the western Chukchi Borderland has illuminated the structure and stratigraphy of the area. Basement rotated fault blocks are offset by two border fault systems (BFS1 and BFS2) and by secondary faults, striking curvilinear in the NW-SE direction, dipping to the NE. The BFS1 dissects the Chukchi Plateau into two first-order rotated blocks bounding two major sedimentary depocentres, the North Chukchi Basin and the Chukchi Plateau Central Basin. The BFS2, which has a larger offset than BFS1, forms the western boundary of the Northwind Basin. Much of the stratigraphy is controlled by sediment supply. The basins were starved early in their history, resulting in a limited syn-rift section. Substantial sediment accumulation in the Borderland appears to post-date large scale progradation of the depostional shelf edge across the Chukchi Shelf. Basin infill stratigraphies are subdivided into pre-rift, syn-rift, early-, middle-, late post-rift, and glacio-marine sequences (SB1-SB5). SB1 shows truncation of the remnants of the pre-rift strata below and onlap of the syn-rift sequence(s) above; the SB2 marks the termination of the rifting stage and is bounded by bi-directional onlap surface of the early post-rift strata above; the base of SB3 is an onlap surface marks the arrival of the prograding shelf margin sequence(s); the SB4 shows evidence of erosion at the base of the prograding late post-rift sequence(s); and the SB5 is an downloap surface marking the first arrival of the glacio-marine sediments eroded from the Chukchi Shelf. Two ages of the major sequence boundaries, the SB3 and SB4, can be directly tied to Popcorn and Crackerjack Chukchi Shelf well data, and the older ones, the end of rifting and the top of the pre-rift, are inferred based on stratigraphic observations. The stratigraphic relationship suggests that the Chukchi Borderland stratigraphy can be correlated in part to the Chukchi Shelf stratigraphy. The first and

  13. The Campanian-Maastrichtian foraminiferal biostratigraphy of the basement sediments from the southern Pannonian Basin (Vojvodina, northern Serbia): implications for the continuation of the Eastern Vardar and Sava zones

    Science.gov (United States)

    Dunčić, Milena; Dulić, Ivan; Popov, Olivera; Bogićević, Goran; Vranjković, Alan

    2017-04-01

    Micropalaeontological and biostratigraphical studies included Campanian-Maastrichtian complexes from five oil exploration wells drilled in northern Serbia (Vojvodina): the first is a carbonate-clastic complex and second is a complex containing ophiolites intercalated with hemipelagic and pelagic sediments. Within the studied complexes, rich associations of planktonic and benthic foraminifera, calcareous nannoplankton, palynomorphs, as well as shallow and deep-water fossil detritus were determined. The presence of relatively rich associations of planktonic foraminifera allowed recognition of two biozones: the Globotruncana ventricosa Zone, observed in the sediments of the carbonate-clastic complex and the Gansserina gansseri Zone, observed in both complexes. Except biozones, based on documented index species, for some units in both complexes, larger benthic foraminifera species had special biostratigraphical value, and in some of them, the calcareous nannoplankton zones were recognized. The studied complexes represent deep-water formations, generated in oceanic island arc and trough zones. The presence of limestones, which originate from destroyed rudist reefs, is explained by transfer by means of gravitational transport mechanisms of shallow-water sediments to deep-water depositional environments. In this paper, the results of more detailed biostratigraphical and palaeo-ecological studies of foraminifera associations in Campanian-Maastrichtian complexes in Vojvodina are presented. Combined with lithological studies, seven units were determined within the complexes. The obtained results are important as a part of multidisciplinary, regional exploration of both complexes, generated in specific geological conditions, that today constitute a part of the pre-Neogene basement complex in the southeastern part of the Pannonian Basin. The Campanian- Maastrichtian carbonate-clastic complex represents sedimentary cover of the Eastern Vardar Ophiolitic Unit, while the

  14. Structural mapping of Chikotra River basin in the Deccan Volcanic ...

    Indian Academy of Sciences (India)

    Ground magnetic data collected over Chikotra River in the peripheral region of Deccan Volcanic Province. (DVP) of Maharashtra located in Kolhapur district was analysed to throw light on the structural pat- tern and distribution of magnetic sources within the basin. In order to isolate the magnetic anomalies showing varying ...

  15. Structural mapping of Chikotra River basin in the Deccan Volcanic ...

    Indian Academy of Sciences (India)

    showing varying trend and amplitude, several transformation operations including wavelength filtering, and upward continuation ... the deeper NW–SE trends are interpreted as the northward extension of the Dharwars, underneath the. Deccan lava flows, that ... basin. Keeping the two objectives, i.e., structural mapping and ...

  16. Tracking the source of mineralisation in the Tampere Basin (southern Finland), insights from structure, sedimentology and geophysics studies

    DEFF Research Database (Denmark)

    Moreau, Julien; Torvela, Taija; Kalliomäki, Henrik

    2013-01-01

    acquired to confirm the position of important intrusions and faults. The field measures have also been backed up with microstructural thin-section analysis and petrography. At a larger scale, public airborne geophysics data have been compared to the geology in order to extend geological contacts when...... with steeply dipping fold axial planes. Despite the evidently large amount of shortening, the primary sedimentary and volcanic structures are generally remarkably well preserved. The Tampere Basin, therefore, offers an excellent opportunity to examine the volcano-sedimentary evolution of an ancient convergent....../or to intense intrusion of igneous material. The continued compression caused a subsequent rotation of the thrusts into their present subvertical position. Some steeply dipping, mineralised fault zones might, therefore, in fact source from relatively shallow depths rather than from deep basement sources....

  17. Combining outcrop, magnetic, and airborne LiDAR data in a course-based undergraduate research experience (CURE): interpretation of bedrock fracturing in the northeastern Deep River Basin and adjacent basement, North Carolina

    Science.gov (United States)

    Pedigo, R.; Waters-Tormey, C. L.; Styers, D.; Hurst, E.

    2017-12-01

    Course-based undergraduate research experiences (CUREs) are a way for students to learn the power of combining geological, geophysical, and geodetic datasets, while also generating new results to answer real questions. A 5-week undergraduate geophysics CURE combined newly released public domain LiDAR-derived ground models with outcrop and magnetic data. The goal was to see if this approach could improve understanding of bedrock fracture sets in the NC Piedmont, which in turn would improve decisions about groundwater resources and proposed hydraulic fracturing of "tight" shale reservoirs in the 230 Ma Deep River failed rift basin. The 10 km2 study area was selected because it straddles the fault contact between crystalline basement and basin sedimentary rocks, it contains 200 Ma NW-SE trending mafic dikes related to successful rifting of Pangea common in the Piedmont, bedrock exposure is typical of the Piedmont (poor), and its land use history is representative of much of the Piedmont. Students visited representative field sites to collect observations then manually identified lineaments in several adjacent LiDAR ground model tiles. Results suggest that (1) lineaments as short as a few m are easily identified except underneath Quaternary deposits, (2) the dominant lineament set trends NW-SE with m- to 10 m-scale spacing, (3) lineaments are better expressed in sedimentary rocks and (4) do not spatially coincide with dike traces. Using field observations, map patterns, and total magnetic intensity profiles across several dikes, the lineaments are interpreted to be edges of subvertical joint fractures recording extension parallel to the dikes' dilation direction. The CURE concluded with students in small groups proposing next steps for the larger research project. The CURE introduced geology majors to the power of using geophysical and remote sensing data with geological data to address geoscience questions. Student feedback was very positive even though the learning

  18. Improved Access To Aging Ocean Basement Biosphere For Microbial Geochemical Studies

    Science.gov (United States)

    Cowen, J. P.; Glazer, B.; Rappe, M.; Kenig, F.; Fisher, A.; Copson, D.; Harris, D.; Jolly, J.; Nuzzio, D.

    2005-12-01

    CORK observatories affixed to Integrated Ocean Drilling Program (IODP) boreholes offer an unprecedented opportunity to study biogeochemical properties and microbial diversity in circulating fluids from sediment-buried ocean basement. Preliminary 16S rRNA gene sequence data from 65 degrees C fluids escaping from the top of the over-pressured ODP borehole 1026B, on the flanks of the Juan de Fuca Ridge indicated the presence of diverse Bacteria and Archaea, including gene clones with varying degrees of relatedness to known dissimilatory nitrate reducers (with ammonia production), thermophilic sulfate reducers, and thermophilic fermentative heterotrophs, consistent with fluid chemistry measurements. However, questions remain regarding microbial community structure, key metabolic pathways and rates, and redox chemistry of the basement fluids, along with concerns for contamination issues. We describe ongoing developments intended to address key in situ analytical and sampling challenges including: 1) The new generation CORKs' dedicated microbiological/geochemical fluid delivery system specifically designed to minimize chemical contamination and surface biofouling; and 2) Development of a seafloor instrument sled for coupling to the CORK's bio-fluid delivery system for acquisition of real-time, in situ electrochemical (voltammetry) redox chemistry data on basement fluids, in addition to in situ particle filtration of basement fluids for molecular genetics, culturing and biogeochemical studies. Results of the first deployment of this instrument sled to new CORK observatory 1301A in Cascadia Basin, on the flanks of the Juan de Fuca Ridge, will be described.

  19. Tectonic structure, seismic stratigraphy and hydrocarbon potential of the North Kara Basin (Russian Arctic)

    Science.gov (United States)

    Verzhbitsky, V.; Kosenkova, N.; Murzin, R.; Vasilyev, V.; Malysheva, S.; Komissarov, D.; Ananyev, V.; Roslov, Yu.; Khudoley, A.

    2012-04-01

    North Kara shelf represents one of the remote and still poorly studied sedimentary megabasins of Russian West Arctic. North Kara area lacks any offshore wells so the understanding of its structure is based on the geology of adjacent East Barents Basin, as well as surrounding land areas (Taimyr, Severnaya and Novaya Zemlya fold belts) and stratigraphic columns of the scattered Arctic Islands. It is widely believed that North Kara shelf is mostly composed of Riphean-Paleozoic sedimentary units, underlain by Precambrian basement (North Kara massif), and represents one of the most promising areas of the Russian Arctic for hydrocarbon (mostly oil) discoveries. Our study is based on the reinterpretation of several regional seismic lines acquired by Sevmorgeo. We used the main Paleozoic and Mesozoic tectonic events known for Severnaya Zemlya Archipelago and Taimyr Peninsula for interpretation of the age of main seismic complexes/boundaries within the North Kara sedimentary cover (first of all within the Priseverozemelsky Trough). We correlated the sharp angular unconformity in the lower part of sedimentary succession with Cambrian/Ordovician unconformity described earlier on the nearby Severnaya Zemlya onshore domain. It is likely that the pre-Ordovician tectonic event corresponds to the Late Baikalian (Timanian) orogeny, which took place on Timan-Pechora and Novaya Zemlya areas. Above the unconformity we proposed the occurrence of Ordovician-Silurian shelfal sedimentary sequence of ~ 2 km thickness. This strata are overlain by thick (~3-4 km) progradational unit. It is likely that this sequence should correspond to molassic deposits of old red sandstones, related to the regional Caledonian orogeny. We believe that general structural pattern of the North Kara region was formed in Late Carboniferous-Early Permian time as a result of Kara massif/Siberian Craton collision-related Hercynian orogeny of Taimyr-Severnaya Zemlya domain. This event led to gentle folding of the

  20. Geotectonic structural interpretation of the basement complex at the eastern border of the Espinhaco ridge, in Guanhaes and Gouveia region, based on an integration of their U/Pb and K/Ar geochronology united

    International Nuclear Information System (INIS)

    Teixeira, W.; Salvador, E.D.; Siga Junior, O.; Sato, K.; Dossin, I.A.; Dossin, T.M.

    1990-01-01

    The basement complex at the eastern border of the Espinhaco ridge is composed of predominantly gneissic rocks which were subjected to migmatization and granitization. Overall the area shows complex tectonic evolution with recurrence of tectonomagmatic and metamorphic events as supported by geological, geochronological and structural studies. The Rb/Sr geochronology carried out on the basement rocks and metavolcanics from the Espinhaco interpreted together with the published U-Pb, Rb-Sr and K-Ar data defines the following scenario for the Precambrian crustal evolution. 1. Primary origin of a sialic crust at 2.97-2.84 Ga. ago as supported by U-Pb zircon ages. 2. Crustal reworking of the Archean crust and subordinate juvenile accretion from upper mantle during the 2.2-2.OGa. period, as suggested by the isochrons. 3. Recurrence of Middle Proterozoic events over the basement rocks (gneisses and charnockites) and metavolcanics of the Espinhaco as showed by isochrons. 4. Development of Late Proterozoic migmatization over the basement rocks (0.75 Ga., R.I.= 0.787) is association with Collisional tectonics and resetting of K-Ar mineral systems. (author)

  1. Evidence of basement controlled faulting of cretaceous strata in the ...

    African Journals Online (AJOL)

    Evidence of basement controlled faulting of cretaceous strata in the Middle Benue Trough, Nigeria from lineament analysis of gravity data. ... anomaly map of part of the Middle Benue Trough, Nigeria, was used to investigate the genetic relationship between the basement and intra-sedimentary structures in the study area.

  2. Possibilities of seismic exploration for crystalline basement study

    Directory of Open Access Journals (Sweden)

    А. Н. Телегин

    2017-03-01

    Full Text Available Possibilities of seismic methods of reflected and refracted waves have been examined for the purposes of detailed study on crystalline basement structure. Investigation of depth and structure of the basement plays an important role in the exploration of various deposits. Sedimentary cover is usually associated with oil and gas reserves. Ore deposits are formed in the basement rocks, basement splits and structure of its surface have a genetic relation not only to ore minerals, but also to oil resources. Reflection seismology is one of the main seismic methods of investigating structural geometry of the sedimentation mass, forecasting its material composition and possible hydrocarbon reserves. However, its possibilities for investigating crystalline basement are limited. Basing on many years’ experience of reflection seismology and physical modeling it has been identified that actual roughness of basement surface limits the obtainable amount of waves reflected from it. Possibilities of reflection seismology for basement structure study are mostly related to investigation of discontinuous faults as diffraction objects using diffracted waves. Method of refracted waves combined with modern procedures and material processing aimed at getting dynamic seismic sections holds much significance for the basement study, especially in the process of surface mapping and, to a lesser extent, in investigating discontinuous faults. Combining seismic methods of reflected and refracted waves in basement study increases reliability of forecasting its geological structure: in particular, its surface can be well defined by means of refraction seismology, and zones of discontinuous faults are identified from diffraction objects using both reflection and refraction methods. As a result of applying both reflection and refraction seismology, an opportunity arises to carry out detailed analysis of basement structure and to predict its oil and gas content.

  3. 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.

  4. Evolution and origin of brines in proterozoic basins in the vicinity of the basement / cover unconformity. Application to uranium deposits in the Kombolgie (Australia) and Athabasca (Canada) basins; Evolution et origine des saumures dans les bassins proterozoiques au voisinage de la discordance socle/couverture. L'exemple de l'environnement des gisements d'uranium associes aux bassins Kombolgie (Australie) et Athabasca (Canada)

    Energy Technology Data Exchange (ETDEWEB)

    Derome, D

    2002-11-01

    The nature, evolution and origin of the fluids circulating at the basis of two Proterozoic sandstone basins (Kombolgie, Australia and Athabasca, Canada), associated with unconformity type uranium mineralization have been characterised. The coupling of several techniques (micro-thermometry, Raman, LIBS) for analysing individual fluid inclusions trapped in different quartz generations, sampled in the vicinity of Australian and Canadian uranium deposits, has led to the quantitative determination of the composition of the paleo-fluids which may have had a role in the genesis of these deposits. The P-T,x evolution of these fluids, in the vicinity of the interface between the basement and the sedimentary cover, has been reconstructed. The proposed fluid circulation model for the two basins is the following: - A sodium dominated chloride-rich brine (15-20 wt% NaCl + 4-12 wt% CaCl{sub 2}), highly oxidising (equilibrated with hematite) is responsible for the early diagenetic silicification. - The circulation of a calcium chloride-rich brine (25-30 wt.% CaCl{sub 2}+0-10 wt.% NaCl) was responsible for the deposition of a second quartz generation and dravite (magnesium-rich tourmaline) in the sandstone at the nose of the reverse basement-rooted faults. The highly calcic nature of this brine probably results from the evolution of the sodic brine through Na{r_reversible}Ca exchange in the basement. A low salinity fluid with traces of methane was heated heated in the basement rocks. It was mixed with the brines at the basis of the Kombolgie basin, during tectonic movements and hydraulic brecciation. This fluid has been rarely observed in the Canadian deposits. This study has shown many similarities between the fluid regimes of the Kombolgie and Athabasca basins. In both districts, a mixing between two Na-Ca-(Mg) chloride brines has been evidenced. Estimated temperatures and depths (about 5 km) are similar for both basins. However the brines observed at the basis of the Athabasca

  5. Magnetic basement in the central Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, K.V.L.N.S.; Ramana, M.V.; Ramprasad, T.; Desa, M.; Subrahmanyam, V.; Krishna, K.S.; Rao, M.M.M.

    . The N10-12 degrees W trending subsurface 85 degrees E Ridge buried under 2 to 3 km thick sediments is a prominent tectonic feature. Offshore basins characterised by deeper magnetic basement (approx. 9 km) and 100-200 km wide are present on either sides...

  6. Sedimentary structure and tectonic setting of the abyssal basins adjoining the southeast part of the Ontong Java Plateau, western Pacific Ocean

    Science.gov (United States)

    Shimizu, S.; Masato, N.; Miura, S.; Suetsugu, D.

    2017-12-01

    Ontong Java Plateau(OJP) in the western Pacific Ocean is one of the largest oceanic plateau in the world. Radioactive ages of drilling samples indicate that the most part of the OJP was emplaced about 122 Ma (Mahoney et al., 1993). Taylor (2006) proposed that the OJP formed as a single large volcanic province together with the Manihiki and Hikurangi plateaus. OJP is surrounding by East Mariana, Pigafetta, Nauru, Ellice, Stewart, and Lyra basins. The East Mariana and Pigafetta basins were formed at the Pacific-Izanagi ridge and the Nauru basin was formed at Pacific-Phoenix ridges (Nakanishi et al., 1992). The tectonic history of the Ellice, Stewart, and Lyra basins is still unknown because of lack of magnetic anomaly lineations. Tectonic setting during the OJP formation is thus a matter of controversy. To expose the tectonic setting of the Ellice, Stewart, and Lyra basins, we conducted the Multi-Channel Seismic (MCS) survey in the basins during the research cruise by R/V Mirai of JAMSTEC in 2014. We present our preliminary results of the MCS survey in the Stewart basin(SB) and Ellice Basin(EB). After the regular data processing, we compared the seismic facies of MCS profile with DSDP Site 288 and ODP Site 1184 to assign ages to seismic reflectors. Our processing exposed several remarkable structures in the basins. The graben structures deformed only the igneous basement in the northwestern and northeastern and southwestern margins of the SB. This suggests the graben structures were formed before sedimentary layer deposited. Taylor (2006) proposed that the basin was formed by the NW-SE rifting during the separation of OJP and Manihiki Plateau around 120 Ma. Neal (1997) proposed that the NE-SW rifting formed the basin around 80 Ma. Our study supports the rifting model proposed by Neal et al. (1997) because the displacement of graben in northeastern and southwestern margins of the SB is larger than that in northwestern of the SB. We found several igneous diapirs in the

  7. Seismic reflection-based evidence of a transfer zone between the Wagner and Consag basins: implications for defining the structural geometry of the northern Gulf of California

    Science.gov (United States)

    González-Escobar, Mario; Suárez-Vidal, Francisco; Hernández-Pérez, José Antonio; Martín-Barajas, Arturo

    2010-12-01

    This study examines the structural characteristics of the northern Gulf of California by processing and interpreting ca. 415 km of two-dimensional multi-channel seismic reflection lines (data property of Petróleos Mexicanos PEMEX) collected in the vicinity of the border between the Wagner and Consag basins. The two basins appear to be a link between the Delfín Superior Basin to the south, and the Cerro Prieto Basin to the north in the Mexicali-Imperial Valley along the Pacific-North America plate boundary. The seismic data are consistent with existing knowledge of four main structures (master faults) in the region, i.e., the Percebo, Santa María, Consag Sur, and Wagner Sur faults. The Wagner and Consag basins are delimited to the east by the Wagner Sur Fault, and to the west by the Consag Sur Fault. The Percebo Fault borders the western margin of the modern Wagner Basin depocenter, and is oriented N10°W, dipping (on average) ˜40° to the northeast. The trace of the Santa María Fault located in the Wagner Basin strikes N19°W, dipping ˜40° to the west. The Consag Sur Fault is oriented N14°W, and dips ˜42° to the east over a distance of 21 km. To the east of the study area, the Wagner Sur Fault almost parallels the Consag Sur Fault over a distance of ˜86 km, and is oriented N10°W with an average dip of 59° to the east. Moreover, the data provide new evidence that the Wagner Fault is discontinuous between the two basins, and that its structure is more complex than previously reported. A structural high separates the northern Consag Basin from the southern Wagner Basin, comprising several secondary faults oriented NE oblique to the main faults of N-S direction. These could represent a zone of accommodation, or transfer zone, where extension could be transferred from the Wagner to the Consag Basin, or vice versa. This area shows no acoustic basement and/or intrusive body, which is consistent with existing gravimetric and magnetic data for the region.

  8. Structural and geological analysis of the northern Pescadero basin: preliminary results based on the analysis of 2D multichannel seismic reflection profiles

    Science.gov (United States)

    Spelz, R. M.; Ramirez-Zerpa, N. A.; Gonzalez-Fernandez, A.; Yarbuh, I.; Contreras, J.

    2017-12-01

    The Pacific-North America plate boundary along the Gulf of California is characterized by an array of right-stepping, right-lateral, transform faults connecting a series of pull-apart basins distributed along the gulf axis. Altogether, these structures accommodate an oblique-divergent component of deformation characterizing the modern tectonic regime along the gulf. The northern Pescadero complex, in the southern Gulf of California, is one of the deepest and probably least studied transtensional fault-termination basins in the gulf. The complex is bounded to the north and south by Atl and Farallon transform faults, respectively, and consists of two asymmetric, rhomboidal-shaped, basins with a series of intrabasinal high-angle normal faults and ramps connecting their depocenters. In this study we present preliminary results derived from the processing and analysis of 400 km of seismic reflection profiles, collected in 2006 onboard the R/V Francisco de Ulloa in northern Pescadero, providing new insights into the geology and internal structure of the basin. Northern Pescadero is a deep and narrow basin characterized by a maximum sedimentary infill of 1 km, and depths to the basin floor exceeding 3500 m. Deformation is chiefly accommodated by an array of self-parallel half-graben structures that appear to grow towards the northern flank of the basin. Faults-scarps located farther from the deformation axis appear to be more degraded, suggesting a progressively younger age of the half-grabens near the basin's depocenter. Another important feature revealed in the seismic images is the lack of sediments on top of the crystalline basement that floors the narrow central portion of the basin. In this area the reflectors at the basin's floor show a pronounced increase in amplitude and coherence, indicating the emplacement of magmatic extrusions. Likewise, in those areas with the greater sediment infill, the occurrence of high-amplitude reflectors, located 150 m below the

  9. Cracked and full of sand: microstructural insights into how oil gets into a crystalline basement reservoir

    Science.gov (United States)

    Holdsworth, Bob; McCaffrey, Ken; Dempsey, Eddie

    2017-04-01

    The fractured Neoarchaean orthogneisses forming the 200km long, NE-SW trending Rona Ridge lie offshore along the southeast margin of the Faroe-Shetland Basin (FSB). The basement ridge was uplifted during Cretaceous-age normal faulting and is flanked and immediately overlain by Devonian to Cretaceous cover sequences. Basement-hosted oil is known to occur in significant volumes in at least two fields (Clair, Lancaster). Re-Os dating of bitumen samples from the Clair Field suggests that oil was generated in the period 64-72Ma. A new microstructural study of basement cores was carried out to assess the mechanisms and timing of oil charge and other fracture-hosted mineralization. Oil charge is everywhere associated with quartz-adularia-calcite-pyrite mineralization and is hosted in a complex mesh of interconnected shear and tensile fractures that formed during a single protracted episode of brittle deformation. This association is recognized in all basement cores containing oil and also in locally overlying well-cemented Devonian (Lower Clair Group) and Jurassic (Rona Sandstone) sequences. Mineralization and oil charge is everywhere associated with clastic sedimentary infillings which occur either as vein-hosted injected slurries, or as little deformed laminated infills in mm to dm-scale open fractures. The latter preserve delicate way-up criteria and geopetal structures. The largest accumulations of oil are found either in these poorly-cemented sedimentary infills, or in fracture-hosted vuggy cavities up to several cm across. All these features, together with the widespread development of zoned mineral cements and cockade textures suggest a low-temperature hydrothermal system that likely formed in a near surface (Jurassic source rocks located to the west in the FSB, through the basement ridge and up into the overlying Clair Group and other cover sequences during the 64-72Ma time period. Our findings have major implications for the development of fractured basement

  10. Microbialitic structures in the Sarmatian carbonate deposits from Simleu Basin

    Directory of Open Access Journals (Sweden)

    Hyam Daoud

    2006-04-01

    Full Text Available The Sarmatian deposits from the Şimleu basin are developed in two facies: terrigenous and calcareous. An attempt to distinguish the main types of Sarmatian limestone microfacies was made by Bucur et al. (1992. The present study provides more detail of the sedimentary facies and fabrics of these limestones, emphasizing the essential contribution of microbialites to their formation. The following types of microbialite and microbial structure were found: (1 thrombolites with clotted fabric and fenestral structures; (2 microbial crusts on bioclasts; (3 peloidal microbialites (4 agglutinated microbialites; (5 stromatolites and laminoid-fenestral structures. All these structures played an important role in the accretion of the Sarmatian carbonate deposits in the area studied.

  11. Structural investigations of Great Basin geothermal fields: Applications and implications

    Energy Technology Data Exchange (ETDEWEB)

    Faulds, James E [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Hinz, Nicholas H. [Nevada Bureau of Mines and Geology, Univ. of Nevada, Reno, NV (United States); Coolbaugh, Mark F [Great Basin Center for Geothermal Energy, Univ. of Nevada, Reno, NV (United States)

    2010-11-01

    Because fractures and faults are commonly the primary pathway for deeply circulating hydrothermal fluids, structural studies are critical to assessing geothermal systems and selecting drilling targets for geothermal wells. Important tools for structural analysis include detailed geologic mapping, kinematic analysis of faults, and estimations of stress orientations. Structural assessments are especially useful for evaluating geothermal fields in the Great Basin of the western USA, where regional extension and transtension combine with high heat flow to generate abundant geothermal activity in regions having little recent volcanic activity. The northwestern Great Basin is one of the most geothermally active areas in the USA. The prolific geothermal activity is probably due to enhanced dilation on N- to NNE-striking normal faults induced by a transfer of NW-directed dextral shear from the Walker Lane to NW-directed extension. Analysis of several geothermal fields suggests that most systems occupy discrete steps in normal fault zones or lie in belts of intersecting, overlapping, and/or terminating faults. Most fields are associated with steeply dipping faults and, in many cases, with Quaternary faults. The structural settings favoring geothermal activity are characterized by subvertical conduits of highly fractured rock along fault zones oriented approximately perpendicular to the WNW-trending least principal stress. Features indicative of these settings that may be helpful in guiding exploration for geothermal resources include major steps in normal faults, interbasinal highs, groups of relatively low discontinuous ridges, and lateral jogs or terminations of mountain ranges.

  12. Structure of the Wagner Basin in the Northern Gulf of California From Interpretation of Seismic Reflexion Data

    Science.gov (United States)

    Gonzalez, M.; Aguilar, C.; Martin, A.

    2007-05-01

    The northern Gulf of California straddles the transition in the style of deformation along the Pacific-North America plate boundary, from distributed deformation in the Upper Delfin and Wagner basins to localized dextral shear along the Cerro Prieto transform fault. Processing and interpretation of industry seismic data adquired by Petroleos Mexicanos (PEMEX) allow us to map the main fault structures and depocenters in the Wagner basin and to unravel the way strain is transferred northward into the Cerro Prieto fault system. Seismic data records from 0.5 to 5 TWTT. Data stacking and time-migration were performed using semblance coefficient method. Subsidence in the Wagner basin is controlled by two large N-S trending sub-parallel faults that intersect the NNW-trending Cerro Prieto transform fault. The Wagner fault bounds the eastern margin of the basin for more than 75 km. This fault dips ~50° to the west (up to 2 seconds) with distinctive reflectors displaced more than 1 km across the fault zone. The strata define a fanning pattern towards the Wagner fault. Northward the Wagner fault intersects the Cerro Prieto fault at 130° on map view and one depocenter of the Wagner basin bends to the NW adjacent to the Cerro Prieto fault zone. The eastern boundary of the modern depocenter is the Consag fault, which extends over 100 km in a N-S direction with an average dip of ~50° (up to 2s) to the east. The northern segment of the Consag fault bends 25° and intersects the Cerro Prieto fault zone at an angle of 110° on map view. The acoustic basement was not imaged in the northwest, but the stratigraphic succession increases its thickness towards the depocenter of the Wagner basin. Another important structure is El Chinero fault, which runs parallel to the Consag fault along 60 km and possibly intersects the Cerro Prieto fault to the north beneath the delta of the Colorado River. El Chinero fault dips at low-angle (~30°) to the east and has a vertical offset of about 0

  13. Basement membrane chondroitin sulfate proteoglycans: localization in adult rat tissues

    DEFF Research Database (Denmark)

    McCarthy, K J; Couchman, J R

    1990-01-01

    Heparan sulfate proteoglycans have been described as the major proteoglycan component of basement membranes. However, previous investigators have also provided evidence for the presence of chondroitin sulfate glycosaminoglycan in these structures. Recently we described the production and characte...

  14. Canada Basin revealed

    Science.gov (United States)

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Chian, D; Lebedeva-Ivanova, Nina; Jackson, Ruth

    2012-01-01

    More than 15,000 line-km of new regional seismic reflection and refraction data in the western Arctic Ocean provide insights into the tectonic and sedimentologic history of Canada Basin, permitting development of new geologic understanding in one of Earth's last frontiers. These new data support a rotational opening model for southern Canada Basin. There is a central basement ridge possibly representing an extinct spreading center with oceanic crustal velocities and blocky basement morphology characteristic of spreading centre crust surrounding this ridge. Basement elevation is lower in the south, mostly due to sediment loading subsidence. The sedimentary succession is thickest in the southern Beaufort Sea region, reaching more than 15 km, and generally thins to the north and west. In the north, grabens and half-grabens are indicative of extension. Alpha-Mendeleev Ridge is a large igneous province in northern Amerasia Basin, presumably emplaced synchronously with basin formation. It overprints most of northern Canada Basin structure. The seafloor and sedimentary succession of Canada Basin is remarkably flat-lying in its central region, with little bathymetric change over most of its extent. Reflections that correlate over 100s of kms comprise most of the succession and on-lap bathymetric and basement highs. They are interpreted as representing deposits from unconfined turbidity current flows. Sediment distribution patterns reflect changing source directions during the basin’s history. Initially, probably late Cretaceous to Paleocene synrift sediments sourced from the Alaska and Mackenzie-Beaufort margins. This unit shows a progressive series of onlap unconformities with a younging trend towards Alpha and Northwind ridges, likely a response to contemporaneous subsidence. Sediment source direction appeared to shift to the Canadian Arctic Archipelago margin for the Eocene and Oligocene, likely due to uplift of Arctic islands during the Eurekan Orogeny. The final

  15. Contribution of the gravimetry to the structural study of the Haouz basin (Morocco

    Directory of Open Access Journals (Sweden)

    El Goumi, N.

    2010-12-01

    Full Text Available The aim of the present study is to improve the knowledge of the Haouz basin structure using gravity data analysis. First of all, a residual anomaly map was computed from the Bouguer anomaly, greatly affected by an important regional gravity gradient. The calculated map provides information on the ground density variations mainly attributed to the top of the Paleozoic basement undulations under the sedimentary cover. However, in order to further study this map, it has been later analyzed with a method that allows evidencing different buried geological structures, combining the horizontal gradient and the upward continuations processing. The obtained results allows us to establish a structural map of the Haouz basin which confirms the existence of structures already recognized or assumed by the classic geological studies, and highlights accidents, as yet, unknown until the present time. This map shows that the fault system of the Haouz basin is organized in two families of directions NE-SW and NW-SE.

    [fr] La présente étude a pour objectif d’améliorer la connaissance de la structure du bassin du Haouz en se basant sur l’analyse des données gravimétriques. Dans un premier temps, une carte des anomalies résiduelle a été calculée à partir de la carte de l’anomalie de Bouguer, fortement affectée par un gradient régional. La carte calculée fournit des informations sur la variation de la densité du sous-sol, expliquée principalement par des ondulations du toit du socle paléozoïque sous la couverture sédimentaire. Toutefois, afin d’exploiter davantage cette carte, celle-ci a été analysée à l’aide d’une méthode qui permet de mettre en évidence les différentes structures géologiques, en combinant le calcul du gradient horizontal et du prolongement vers le haut. Les résultats obtenus ont permis d’établir une carte structurale du bassin du Haouz qui confirme l’existence de structures déjà reconnues ou

  16. Design of Gravity Survey Network using Fractal Theory to Delineate Hydrocarbon bearing Jabera Structure, Vindhyan Basin, Central India

    Science.gov (United States)

    Dimri, V. P.; Srivastava, R. P.; Vedanti, N.

    2006-12-01

    from the 2D scaling spectral analysis of the data. Results of the scaling spectral method reveals that in the study area, there are three main depth interfaces at 5 km, 1.5 km and 0.8 km respectively which corresponds to the basement and lower Vindhyan interface, lower Vindhyan and Upper Vindhyan interface and upper most is the terrain clearance. For quantitative interpretation, we selected a profile across the target structure (reported as Jabera dome) and modeling of the gravity data acquired along the profile was carried out using Marquardt inversion approach. This profile is selected in order to estimate the tentative geological cross section across the conspicuous low gravity anomaly observed in the southern part of the study area. Deep Seismic Sounding (DSS) studies carried out by earlier workers indicated presence thick sediments in this part of the Vindhyan basin. The gravity anomaly drawn along this profile shows a typical anomaly pattern of a sedimentary basin faulted on its both margins. The modeling results show that the anomaly corresponds to a deep faulted basin in the crystalline basement in which the upper layer with density value of 2.46 g/cc corresponds to the upper Vindhyan rocks. This layer is underlain by a thick layer (1.0 to 6.5 km) of lower Vindhyan sediments. This layer which has gentle slope from NW to SE direction sits over the high density rocks comprising of Bijawar/Mahakoshal group.

  17. Measure Guideline: Basement Insulation Basics

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, R.; Mantha, P.; Puttagunta, S.

    2012-10-01

    This guideline is intended to describe good practices for insulating basements in new and existing homes, and is intended to be a practical resources for building contractors, designers, and also to homeowners.

  18. Cell invasion through basement membrane

    OpenAIRE

    Morrissey, Meghan A; Hagedorn, Elliott J; Sherwood, David R

    2013-01-01

    Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recent...

  19. Thick-skinned tectonics in a Late Cretaceous-Neogene intracontinental belt (High Atlas Mountains, Morocco): The flat-ramp fault control on basement shortening and cover folding

    Science.gov (United States)

    Fekkak, A.; Ouanaimi, H.; Michard, A.; Soulaimani, A.; Ettachfini, E. M.; Berrada, I.; El Arabi, H.; Lagnaoui, A.; Saddiqi, O.

    2018-04-01

    Most of the structural studies of the intracontinental High Atlas belt of Morocco have dealt with the central part of the belt, whose basement does not crop out. Here we study the Alpine deformation of the North Subatlas Zone, which is the part of the Western High Atlas (WHA) Paleozoic Massif that involves both Paleozoic basement units and remnants of their Mesozoic-Cenozoic cover formations. Our aim is to better constrain the geometry and kinematics of the basement faults during the Alpine shortening. Based on detail mapping, satellite imagery and field observations, we describe an array of sub-equatorial, transverse and oblique faults between the WHA Axial Zone and the Haouz Neogene basin. They define a mosaic of basement blocks pushed upon one another and upon the Haouz basement along the North Atlas Fault (NAF). The Axial Zone makes up the hanging-wall of the Adassil-Medinet Fault (AMF) south of this mosaic. The faults generally presents flat-ramp-flat geometry linked to the activation of multiple décollement levels, either within the basement where its foliation is subhorizontal or within favourable cover formations (Jurassic evaporites, Lower Cretaceous silty red beds, Upper Cretaceous evaporitic marls, Neogene basal argillites). The occurrence of the North Atlas detachment (NAD) allowed folded pop-up units to develop in front of the propagating NAF. Shortening began as early as the Campanian-Maastrichtian along the AMF. The direction of the maximum horizontal stress rotated from NNE-SSW to NNW-SSE from the Maastrichtian-Paleocene to the Neogene. The amount of shortening reaches 20% in the Azegour transect. This compares with the shortening amount published for the central-eastern High Atlas, suggesting that similar structures characterize the Paleozoic basement all along the belt. The WHA thick-skinned tectonics evokes that of the frontal Sevier belt and of the external Western Alps, although with a much minor pre-inversion burial.

  20. The early-stage structural evolution of the Barmer Basin rift, Rajasthan, northwest India

    OpenAIRE

    Bladon, Andrew John

    2015-01-01

    The structural evolution of the Barmer Basin and the context of the rift within the northwest Indian region are poorly understood, despite being a prolific hydrocarbon province. In this work an integrated basin analysis is presented covering the outcrop-, seismic-, and lithosphere-scales. The early-stage structural evolution and the origin of poorly understood structural complications in the Barmer Basin subsurface are assessed. Subsequently, the findings are placed within the wider context o...

  1. Viruses in the Oceanic Basement.

    Science.gov (United States)

    Nigro, Olivia D; Jungbluth, Sean P; Lin, Huei-Ting; Hsieh, Chih-Chiang; Miranda, Jaclyn A; Schvarcz, Christopher R; Rappé, Michael S; Steward, Grieg F

    2017-03-07

    Microbial life has been detected well into the igneous crust of the seafloor (i.e., the oceanic basement), but there have been no reports confirming the presence of viruses in this habitat. To detect and characterize an ocean basement virome, geothermally heated fluid samples (ca. 60 to 65°C) were collected from 117 to 292 m deep into the ocean basement using seafloor observatories installed in two boreholes (Integrated Ocean Drilling Program [IODP] U1362A and U1362B) drilled in the eastern sediment-covered flank of the Juan de Fuca Ridge. Concentrations of virus-like particles in the fluid samples were on the order of 0.2 × 10 5 to 2 × 10 5  ml -1 ( n = 8), higher than prokaryote-like cells in the same samples by a factor of 9 on average (range, 1.5 to 27). Electron microscopy revealed diverse viral morphotypes similar to those of viruses known to infect bacteria and thermophilic archaea. An analysis of virus-like sequences in basement microbial metagenomes suggests that those from archaeon-infecting viruses were the most common (63 to 80%). Complete genomes of a putative archaeon-infecting virus and a prophage within an archaeal scaffold were identified among the assembled sequences, and sequence analysis suggests that they represent lineages divergent from known thermophilic viruses. Of the clustered regularly interspaced short palindromic repeat (CRISPR)-containing scaffolds in the metagenomes for which a taxonomy could be inferred (163 out of 737), 51 to 55% appeared to be archaeal and 45 to 49% appeared to be bacterial. These results imply that the warmed, highly altered fluids in deeply buried ocean basement harbor a distinct assemblage of novel viruses, including many that infect archaea, and that these viruses are active participants in the ecology of the basement microbiome. IMPORTANCE The hydrothermally active ocean basement is voluminous and likely provided conditions critical to the origins of life, but the microbiology of this vast habitat is not

  2. Tectonic stages in Southern Greater Caucasus and Adjara Trialeti belt in Georgia: new results on timing and structures of inverted basins

    Science.gov (United States)

    Candaux, Zoé; Sosson, Marc; Adamia, Shota; Sadradze, Nino; Alania, Victor; Enukidze, Onise; Chabukiani, Alexandre

    2017-04-01

    observed in the Greater Caucasus, forelands basins (Kura and Rioni basins) and in the Adjara-Trialeti belt are different: some are linked to thin-skinned tectonic deformations while some induces deformation at depth (thick-skinned tectonic). These observations outline the role of the inherited structures within the basement. The normal faults due to the previous extensional stages are reactivated as thrust during collision while detachment levels are observed in deposits not involved in the extensional stages. These observations bring out the importance of the chronology of the different tectonic stages to better understand the tectonic frame and geodynamic processes involved from the Early Cretaceous in this area and the role on the resulting structures.

  3. Thermal structure research on cenozoic in Songliao basin and Daxinganling Mountain

    International Nuclear Information System (INIS)

    Fang Shi; Liu Zhaojun; Guo Wei

    2005-01-01

    Thermal history simulation of Apatite Fission Track shows the thermal structure history in Cenozoic and the relationship between Songliao Basin and Daxinganling Mountain. Uplift of Daxinganling reveals its act character; its velocity shows 5 decreasing phases and 4 increasing ones. Although basin evolvement is quite complex, it behaved as three uplifts and two sedimentations. It is considered here that the relationship between Songliao Basin and Daxinganling includes three styles and 4 phases, that is, basin uplifted with mountain during 65.5-50 Ma; basin subsided while mountain uplifted slowly and basin uplifted rapidly while mountain uplifted rapidly during 50-36 Ma; basin subsided slowly while mountain uplifted slowly and basin subsided rapidly while mountain uplifted rapidly during 36-5.83 Ma; the latest phase was the same with the first one. (authors)

  4. The role of Mesozoic sedimentary basin tapers on the formation of Cenozoic crustal shortening structures and foredeep in the western Sichuan Basin, China

    Science.gov (United States)

    Wang, M.

    2017-12-01

    The foreland basin records important clues of tectonic and sedimentary process of mountain-building, thus to explore its dynamic mechanism on the formation is an important issue of the mountain-basin interaction. The Longmen Shan fold-and-thrust belt and its adjacent Sichuan basin located in the eastern margin of Tibetan Plateau, are one of the most-concerned regions of studying modern mountain-building and seismic process, and are also a natural laboratory of studying the dynamics of the formation and development of foreland basin. However, it still need further explore on the mechanics of the development of the Cenozoic foreland basin and thrust-belts in the western Sichuan Basin. The Longmen Shan thrust belt has experienced multi-stages of tectonics evolution, foreland basin formation and topography growth since Late Triassic, and whether the early formed basin architecture and large Mesozoic sedimentary basin taper can influence the formation and development of the Cenozoic foreland basin and thrust belts? To solve these issues, this project aim to focus on the Cenozoic foreland basin and internal crustal shortening structures in the western Sichuan basin, on the basis of growth critical wedge taper theory. We will reconstruct the shape of multi-phases of sedimentary basin tapers, the temporal-spatial distribution of crustal shortening and thrusting sequences, and analyze the control mechanism of Mesozoic sedimentary basin taper on the formation of Cenozoic foreland basins, and final explore the interaction between the tectonics geomorphology, stress field and dynamic propagation of foreland basin.

  5. Three-dimensional structure and evolution of an asymmetric pull-apart basin

    Science.gov (United States)

    Sagy, Amir; Hamiel, Yariv

    2017-07-01

    The structure of a 250-m-long asymmetrical pull-apart basin developed in carbonate rocks at the Galilee heights, Israel, is herein analyzed. The reconstruction of the basin geometry is based on detailed mapping and LiDAR measurements of fault scarps. The architecture of faults is then used as a boundary condition for calculating the stress pattern in the vicinity of the basin, using a dislocation model. The basin is found to be an asymmetrical V-shaped structure bordered by two longitudinal oblique right-lateral strike-slip faults. The strike of one of the faults is bent at the eastern edge of the basin, generating a transverse boundary fault which joins the second boundary fault orthogonally. The overall lateral displacement is smaller than the basin length, and no transverse or diagonal fault is observed in the western end of the basin. The deformation around the basin is mostly displayed by fractures. Yet, folds and fault branches are observed near the tips of the boundary faults and near kink points of fault segments. Stress analysis obtained by the three-dimensional model is in general agreement with the orientation of fractures and location of high deformation regions in and around the basin. Based on our observations, we present a conceptual model which demonstrates the development of asymmetric basins in releasing bends and sheds light on the structures of similar large pull-apart basins.

  6. Tectonic types of deepwater basins and structural segmentation of the North Atlantic

    Science.gov (United States)

    Pushcharovsky, Yu. M.

    2012-03-01

    Typification of tectonic structures is one of the important lines of tectonic research. Recently, I have published several articles, which are concerned with deepwater oceanic basins. This paper is focused on tectonic typification of deepwater basins of the North Atlantic. They are attributed to three types: perispreading, central thalassogenic, and pericontinental. The first type comprises the Irminger, Iceland, Greenland, and Lofoten basins. The first two basins are associated with the Reykjanes Ridge and the two others, with the Mohns Ridge. The central thalassogenic type is exemplified in the Norwegian Basin, while the pericontinental type in the Rockall Trough. Two systems of basins are distinguished by morphostructural and historical-geological features: the northern system of the Oligocene-Quaternary structures and the southern system of the Paleocene-Quaternary structures. The Greenland-Faroe tectonovolcanic zone serves as their tectonic interface. In the tectonic typology of their deepwater basins, the North Atlantic is closer to the Indian than to other oceans. The present-day configuration of the northern basins is determined by neotectonics. The tectonic movements in the northern system of basins at this stage were more contrasting than in the southern system. This explains the greater depth of the former basins. The spatial position of the deepwater basins belonging to different types determines the tectonic segmentation of the oceanic bottom. The southern, central, and northern latitudinal segments correspond to different geodynamic states of the Earth's interior.

  7. Depth of magnetic basement in Iran based on fractal spectral analysis of aeromagnetic data

    Science.gov (United States)

    Teknik, Vahid; Ghods, Abdolreza

    2017-06-01

    To estimate the shape of sedimentary basins, a critical parameter in hydrocarbon exploration, we calculated the depth of magnetic basement by applying a fractal spectral method to the aeromagnetic map of Iran. The depth of magnetic basement is a close proxy for the shape of sedimentary basins provided that igneous basement is strongly magnetized relative to the overlying sediments and there is no interbedding magnetic layer in the sediments. The shape of the power spectrum of magnetic anomalies is sensitive to the depth of magnetic basement, the thickness of the magnetic layer, the fractal parameter of magnetization and the size of the window used for the calculation of the power spectrum. Using a suite of synthetic tests, we have shown that the estimation of the depth of magnetic basement of up to 20 km is not very sensitive to the often unknown fractal parameter and thus the spectral method is a reliable tool to calculate the depth of magnetic basement. The depth of magnetic basement is in the range of 7-16 km in the Zagros, east Alborz, Tabas, Jazmurian and Makran regions, showing a close correlation with depths estimated from the maximum thickness of stratigraphic columns. We have also found new sedimentary basins in Bostan Abad, Bijar and south of Orumiyeh Lake. The significant depth of the magnetic basement in the Makran, Jazmurain depression, southeast Caspian Sea, Tabas, Great Kavir, south of Orumiyeh Lake, Bostan Abad and Bijar sedimentary basins makes them future prospects for hydrocarbon explorations. The depth of magnetic basement is strongly reduced over the Neyriz and Kermanshah Ophiolites, but it does not show any meaningful correlation with other outcrops of ophiolitic rocks in Iran.

  8. Geostatistical Interplay Between Geophysical and Geochemical Data: Mapping Litho-Structural Assemblages of Mesozoic Igneous Activities in the Parnaíba Basin (NE Brazil)

    Science.gov (United States)

    de Castro, David L.; Oliveira, Diógenes C.; Hollanda, Maria Helena B. M.

    2018-02-01

    Two widespread magmatic events are recorded in the Parnaíba basin (NE Brazil) during the Jurassic/Cretaceous opening of the Central and South Atlantic Oceans. The Early Jurassic ( 200 Ma) lava flows of the Mosquito Formation occur essentially in the western and southern basin segments, representing one of the largest expressions of the Central Atlantic Magmatic Province in the South American Plate. In contrast, sill complexes and dike swarms of the Early Cretaceous (129-124 Ma) Sardinha Formation occur in the eastern part of the basin and are chrono-correlated to the large Paraná-Etendeka igneous province and to the Rio Ceará-Mirim Dike Swarm. We gathered geophysical, well logging, outcrop analogs and geochemical data to recognize geometrical shapes and areal distribution patterns of igneous-related constructions. Seismic and well data reveal hundreds of km wide multilayered sill complexes and dikes, which are widespread across vast regions of the basin without evident structural control from either the Precambrian basement grain or the basin internal architecture. Anomaly enhancement techniques and self-organizing maps (SOM) procedure were applied on airborne magnetic data, unraveling near-surface magmatic features in four distinct magnetic domains. Using SOM analysis, the basaltic rocks were divided into six groups based on magnetic susceptibility and major elements composition. These results suggest common origin for both magmatic episodes, probably a combination of effects of edge-driven convection and large-scale mantle warming under the westward moving West Gondwana during the Central and South Atlantic opening, which caused a shifted emplacement to the east of the igneous rocks in the Parnaíba basin.

  9. Crustal Structure Within the Southeastern Carpathian Arc, Transylvanian Basin, Romania from Teleseismic Receiver Functions

    Science.gov (United States)

    Stanciu, A. C.; Russo, R. M.; Mocanu, V. I.; Munteanu, L.

    2013-05-01

    We present new measurements of receiver functions at 4 broadband stations temporarily deployed in the Transylvanian Basin within the Carpathian Arc, Romania. Receiver functions can reveal depths to sharp crustal seismic velocity boundaries, which in complex tectonic environments such as the study area provide a good diagnostic for the regional tectonics. As a result of Africa (Adria) collision with Europe and subduction of a part of Tethys Ocean, Tisza-Dacia and Alcapa blocks escaped the collision and were emplaced in an embayment of this ocean, and form today the basement of the Transylvanian Basin. The collision of these terranes with the European continent culminated in the formation, in the Romanian part, of the Eastern Carpathians at the contact between the Transylvanian Basin and the East European Platform along the Tornquist-Teisseyre Suture zone, and of Southern Carpathians at the contact with Moesian Platform. In the foreland of the Carpathian Bend Zone, connecting the two mountain chains, in a very constrained area, a high velocity seismic body was contoured by hypocenters between 70 and 200 km depth. We constructed receiver functions using teleseismic P waves generated by events located between 30 and 95 degrees epicentral angle using the method of Ligorria and Ammon (1999) for individual measurements. We used the H-K method of Zhu and Kanamori (2000) to derive boundary interfaces depths and receiver function complexity from binned stacks. Preliminary results show a relatively shallow Moho depth beneath the Transylvanian Basin.

  10. Analysis of gravity anomalies in the Ulleung Basin (East Sea/Sea of Japan) and its implications for the crustal structure of rift-dominated back-arc basin

    Science.gov (United States)

    Kim, Yoon-Mi; Lee, Sang-Mook

    2018-01-01

    The Ulleung Basin (UB), one of three major basins in the East Sea/Sea of Japan, is considered to represent a continental-rifting end-member of back-arc basin system, but is much less understood compared to the nearby Yamato Basin (YB) and Japan Basin (JB). This study examines the gravity anomalies of the UB since the variation in crustal thickness can provide important insights on the mode of extension during basin opening. Our analysis shows that the Moho depth (from the sea surface) varies from 16 km at the basin center to 22 km at the edges. However, within the central part of the basin, the crustal thickness (not including sediment) is more or less the same (10-12 km), by varying only about 10-20% of the total thickness, contrary to the previous suggestions. Our finding of anomalous but uniformly thick crust is consistent with the recent seismic results from the YB (14 km on average). A mantle residual gravity anomaly high (∼20 mGal) exists in the northeastern part of the UB. This feature is interpreted as the location of maximum extension (slightly thinner crust by ∼1 km). Together with another moderate gravity high to the southwest, the two anomalies form a NNE-SSW line, which corresponds to the direction of the major tectonic structures of the Korean Peninsula. We argue that the a massive magmatic emplacement took place extensively in the lower crust of the UB during the opening, significantly increasing its overall thickness to almost twice as that of the JB where a mid-ocean-ridge style seafloor spreading occurred. Two important post-opening processes took place after the formation of uniformly thick crust: post-rift volcanic intrusions in the north, especially in its northeast sections but had little effect on the residual gravity anomaly itself, and the deflection of crust in response to differential sediment loading towards the south, producing the median high in the basement in response to the flexural bending. We also conducted a simple test to

  11. Tectonic characteristics and structural styles of a continental rifted basin: Revelation from deep seismic reflection profiles

    Directory of Open Access Journals (Sweden)

    Yuan Li

    2016-09-01

    Full Text Available The Fushan Depression is a half-graben rifted sub-basin located in the southeast of the Beibuwan Basin, South China Sea. The Paleogene Liushagang sequence is the main hydrocarbon-bearing stratigraphic unit in the sub-basin. Using three-dimensional (3-D seismic data and logging data over the sub-basin, we analyzed structural styles and sedimentary characteristics of the Liushagang sequence. Five types of structural styles were defined: ancient horst, traditional slope, flexure slope-break, faulted slope-break and multiple-stage faults slope, and interpretations for positions, background and development formations of each structural style were discussed. Structural framework across the sub-basin reveals that the most remarkable tectonic setting is represented by the central transfer zone (CTZ which divides the sub-basin into two independent depressions, and two kinds of sequence architectures are summarized: (i the western multi-stage faults slope; (ii the eastern flexure slope break belt. Combined with regional stress field of the Fushan Depression, we got plane combinations of the faults, and finally built up plan distribution maps of structural system for main sequence. Also, we discussed the controlling factors mainly focused on subsidence history and background tectonic activities such as volcanic activity and earthquakes. The analysis of structural styles and tectonic evolution provides strong theoretical support for future prospecting in the Fushan sub-basin and other similar rifted basins of the Beibuwan Basin in South China Sea.

  12. Viruses in the Oceanic Basement

    Directory of Open Access Journals (Sweden)

    Olivia D. Nigro

    2017-03-01

    Full Text Available Microbial life has been detected well into the igneous crust of the seafloor (i.e., the oceanic basement, but there have been no reports confirming the presence of viruses in this habitat. To detect and characterize an ocean basement virome, geothermally heated fluid samples (ca. 60 to 65°C were collected from 117 to 292 m deep into the ocean basement using seafloor observatories installed in two boreholes (Integrated Ocean Drilling Program [IODP] U1362A and U1362B drilled in the eastern sediment-covered flank of the Juan de Fuca Ridge. Concentrations of virus-like particles in the fluid samples were on the order of 0.2 × 105 to 2 × 105 ml−1 (n = 8, higher than prokaryote-like cells in the same samples by a factor of 9 on average (range, 1.5 to 27. Electron microscopy revealed diverse viral morphotypes similar to those of viruses known to infect bacteria and thermophilic archaea. An analysis of virus-like sequences in basement microbial metagenomes suggests that those from archaeon-infecting viruses were the most common (63 to 80%. Complete genomes of a putative archaeon-infecting virus and a prophage within an archaeal scaffold were identified among the assembled sequences, and sequence analysis suggests that they represent lineages divergent from known thermophilic viruses. Of the clustered regularly interspaced short palindromic repeat (CRISPR-containing scaffolds in the metagenomes for which a taxonomy could be inferred (163 out of 737, 51 to 55% appeared to be archaeal and 45 to 49% appeared to be bacterial. These results imply that the warmed, highly altered fluids in deeply buried ocean basement harbor a distinct assemblage of novel viruses, including many that infect archaea, and that these viruses are active participants in the ecology of the basement microbiome.

  13. Integrated geophysical data processing and interpretation of crustal structure in Ethiopia with emphasis on the Ogaden Basin and adjacent areas

    Science.gov (United States)

    Tadesse, Ketsela

    . Integrated gravity models in the southwest part of the Ogaden basin indicate a sediment thickness of 8 km. Interpretation of seismic reflection data indicates potential stratigraphic and structural traps for hydrocarbons in the Ogaden basin. Older strata such as the Karroo strata appear to pinch out towards the uplifted basement to the northwest. Fault structures are associated with the basement. Channels that appear as distinct features on 2D reflection seismic data may be developed in various places with hanging wall incision. Attribute analysis and interpretation suggest possible hydrocarbon bearing zones or at least porous formations and continuity of reflection horizons. (Abstract shortened by UMI.)

  14. Basement membrane proteoglycans and development

    DEFF Research Database (Denmark)

    Couchman, J R; Abrahamson, D R; McCarthy, K J

    1993-01-01

    -CSPG was only strongly expressed in the vasculature invading late comma stage glomeruli, and later in presumptive and mature Bowman's capsule. Over the first six to eight weeks, the capillary basement membranes contained BM-CSPG, but in gradually decreasing amounts until it became completely undetectable...

  15. Three-Dimensional Inversion of Magnetotelluric Data for the Sediment–Basement Interface

    DEFF Research Database (Denmark)

    Cai, Hongzhu; Zhdanov, Michael

    2016-01-01

    and a resistive basement. Conventional inversions of MT data are aimed at determining the volumetric distribution of the conductivity within the inversion domain. The recovered distribution of the subsurface conductivity is typically diffusive, which makes it difficult to select the sediment-basement interface....... This letter develops a novel approach to 3-D MT inversion for the depth-to-basement estimate. The key to this approach is selection of the model parameterization, with the depth to basement being the major unknown parameter. In order to estimate the depth to the basement, the inversion algorithm recovers both...... the thickness and the conductivities of the sedimentary basin. The forward modeling is based on the integral equation approach. The inverse problem is solved using a regularized conjugate gradient method. The Fréchet derivative matrix is calculated based on quasi-Born approximation. The developed method...

  16. Santos Basin Geological Structures Mapped by Cross-gradient Method

    Science.gov (United States)

    Jilinski, P.; Fontes, S. L.

    2011-12-01

    Introduction We mapped regional-scale geological structures localized in offshore zone Santos Basin, South-East Brazilian Coast. The region is dominated by transition zone from oceanic to continental crust. Our objective was to determine the imprint of deeper crustal structures from correlation between bathymetric, gravity and magnetic anomaly maps. The region is extensively studied for oil and gas deposits including large tectonic sub-salt traps. Our method is based on gradient directions and their magnitudes product. We calculate angular differences and cross-product and access correlation between properties and map structures. Theory and Method We used angular differences and cross-product to determine correlated region between bathymetric, free-air gravity and magnetic anomaly maps. This gradient based method focuses on borders of anomalies and uses its morphological properties to access correlation between their sources. We generated maps of angles and cross-product distribution to locate correlated regions. Regional scale potential fields maps of FA and MA are a reflection of the overlaying and overlapping effects of the adjacent structures. Our interest was in quantifying and characterizing the relation between shapes of magnetic anomalies and gravity anomalies. Results Resulting maps show strong correlation between bathymetry and gravity anomaly and bathymetry and magnetic anomaly for large strictures including Serra do Mar, shelf, continental slope and rise. All maps display the regional dominance of NE-SW geological structures alignment parallel to the shore. Special interest is presented by structures transgressing this tendency. Magnetic, gravity anomaly and bathymetry angles map show large correlated region over the shelf zone and smaller scale NE-SW banded structures over abyssal plane. From our interpretation the large band of inverse correlation adjacent to the shore is generated by the gravity effect of Serra do Mar. Disrupting structures including

  17. Structural Model of the Tucupita Field, Eastern Venezuela Basin

    Science.gov (United States)

    Arteaga, L. A.

    2013-05-01

    The Tucupita Field has an area of 73,51 Km2, is located between the states of Monagas and Delta Amacuro, geologically is located at the greater Temblador area in the Eastern Venezuela Basin, where the Oficina Formation's sands represent the main hydrocarbons reservoirs. From the results of the seismic reprocessing realized by Fusion Petroleum Technologies, Inc., the structural model of this field was done as initial step to the geocellular model of the Oficina-40 Reservoir, which was defined as a Faulted Relay Ramp, where the normal faults are dominant with NE-SW orientation Introduction The Tucupita Field is a mature oilfield at the greater Temblador area, however most of the wells were completed in the upper sands, therefore the main study is focused in the geological characterization of the Oficina-40 Reservoir's lower sands, starting by the structural model Previous Studies 1. Proyecto Tucupita 3D The seismic data of the Tucupita Field were adquired in 1996 by Western Atlas of Venezuela for the Benton Vinccler Company. The UTM coordinates of the wells used in this project, have been taken to make this geological model 2. Soporte Geofísico Integrado The seismic project Tucupita was processed by Fusion Petroleum Technologies Inc., in Houston and consisted of reprocessing and pre-stack migration in time (PSTM) and pre-stack migration in depth (PSDM), this data belong to the Petrodelta Company Based on the regional stratigraphy, were validated the "picks" to make the structural sections to support research with hard data. After, it proceeded to interpret the structural style of the field from the seismic amplitude cube. Then, it was done the faults modelling and the stratigraphic horizons to carry out the geocellular model Three structural sections were realized, which was interpreted like a faulted monocline, whose peak is located southward, where justly the wells are located. The contact oil-water was interpreted to -5648'. Echelon faults were interpreted in a

  18. Rift brittle deformation of SE-Brazilian continental margin: Kinematic analysis of onshore structures relative to the transfer and accommodation zones of southern Campos Basin

    Science.gov (United States)

    Savastano, Vítor Lamy Mesiano; Schmitt, Renata da Silva; Araújo, Mário Neto Cavalcanti de; Inocêncio, Leonardo Campos

    2017-01-01

    High-resolution drone-supported mapping and traditional field work were used to refine the hierarchy and kinematics of rift-related faults in the basement rocks and Early Cretaceous mafic dikes onshore of the Campos Basin, SE-Brazil. Two sets of structures were identified. The most significant fault set is NE-SW oriented with predominantly normal displacement. At mesoscale, this fault set is arranged in a rhombic pattern, interpreted here as a breached relay ramp system. The rhombic pattern is a penetrative fabric from the thin-section to regional scale. The second-order set of structures is an E-W/ESE-WNW system of normal faults with sinistral component. These E-W structures are oriented parallel with regional intrabasinal transfer zones associated with the earliest stages of Campos Basin's rift system. The crosscutting relationship between the two fault sets and tholeiitic dikes implies that the NE-SW fault set is the older feature, but remained active until the final stages of rifting in this region as the second-order fault set is older than the tholeiitic dikes. Paleostresses estimated from fault slip inversion method indicated that extension was originally NW-SE, with formation of the E-W transfer, followed by ESE-WNW oblique opening associated with a relay ramp system and related accommodation zones.

  19. Structural safety evaluation of the K Basin railcar and truck applications

    International Nuclear Information System (INIS)

    Winkel, B.V.

    1995-08-01

    There are two rail spurs in the storage/transfer areas of both the K East and K West fuel storage basins. These rail spurs both end at the west edge of the basins. To avoid accidental entry of a railcar into a basin, administrative procedures and rail control hardware have been provided. Based upon a combination of historical documentation and existing adminstrative controls, a maximum credible impact accident was established. Using this design basis accident, the existing rail control hardware was evaluated for structural adequacy. The K Basin rail spurs are embedded in concrete, which permits truck/trailer entry into the same area. Safety issues for truck applications are also addressed

  20. Present-day 3D structural model of the Po Valley basin, Northern Italy

    NARCIS (Netherlands)

    Turrini, C.; Lacombe, O.; Roure, F.

    2014-01-01

    A 3D structural model of the Po Valley basin (Northern Italy) was built by integrating the dataset available from the public domain (DEM, wells, isobath-maps, cross-sections, outcrop-trends).The model shows the complex foredeep-foreland architecture across the basin, from the Moho level to the

  1. Heat flow, deep formation temperature and thermal structure of the Tarim Basin, northwest China

    Science.gov (United States)

    Liu, Shaowen; Lei, Xiao; Feng, Changge; Li, Xianglan

    2016-04-01

    Geothermal regime of a sedimentary basin not only provides constraint on understanding the basin formation and evolution, but also offers fundamental parameters for hydrocarbon resources assessment. As one of three Precambrian blocks in China, the Tarim craton is also a current hydrocarbon exploration target where the largest sedimentary basin (Tarim Basin) develops with great potential. Although considerable advancement of geothermal regime of this basin has been made during the past decades, nearly all the temperature data in previous studies are from the exploration borehole formation testing temperatures. Recently, we have conducted the steady-state temperature logging in the Tarim basin, and measured abundant rock thermal properties, enabling us to re-visit the thermal regime of this area with more confidence. Our results show that the present-day geothermal gradients for the Tarim Basin vary from 23 K/km to 27 K/km, with a mean of 22 K/km; the values of heat flow range from 40 mW/m2 to 49 mW/m2, with a mean of 43 mW/m2. These new data confirmed that the Tarim Basin has relatively low heat flow and shares similar geothermal regime with other Precambrian cratons in the world. In addition, the new temperatures from the steady-state logs are larger than the bottom hole temperatures (BHT) as 22 degree Celsius, indicating the thermal non-equilibrium for the BHTs used in previous studies. Spatial distribution of the estimated formation temperatures-at-depth of 1~5km within the basin is similar and mainly controlled by crystalline basement pattern. Generally, the temperatures at the depth of 1km range from 29 to 41 degree Celsius, with a mean of 35 degree Celsius; while the temperatures at 3km vary from 63 to 100 degree Celsius, and the mean is 82 degree Celsius; at 5km below the surface, the temperatures fall into a range between 90 and 160 degree Celsius, with a mean of 129 degree Celsius. We further proposed the long-term low geothermal background and large burial

  2. Andean Basin Evolution Associated with Hybrid Thick- and Thin-Skinned Deformation in the Malargüe Fold-Thrust Belt, Western Argentina

    Science.gov (United States)

    Horton, B. K.; Fuentes, F.

    2015-12-01

    Andean deformation and basin evolution in the Malargüe fold-thrust belt of western Argentina (34-36°S) has been dominated by basement faults influenced by pre-existing Mesozoic rift structures of the hydrocarbon-rich Neuquen basin. However, the basement structures diverge from classic inversion structures, and the associated retroarc basin system shows a complex Mesozoic-Cenozoic history of mixed extension and contraction, along with an enigmatic early Cenozoic stratigraphic hiatus. New results from balanced structural cross sections (supported by industry seismic, well data, and surface maps), U-Pb geochronology, and foreland deposystem analyses provide improved resolution to examine the duration and kinematic evolution of Andean mixed-mode deformation. The basement structures form large anticlines with steep forelimbs and up to >5 km of structural relief. Once the propagating tips of the deeper basement faults reached cover strata, they fed slip to shallow thrust systems that were transported in piggyback fashion by newly formed basement structures, producing complex structural relationships. Detrital zircon U-Pb ages for the 5-7 km-thick basin fill succession reveal shifts in sedimentation pathways and accumulation rates consistent with (1) local basement sources during Early-Middle Jurassic back-arc extension, (2) variable cratonic and magmatic arc sources during Late Jurassic-Cretaceous postrift thermal subsidence, and (3) Andean arc and thrust-belt sources during irregular Late Cretaceous-Cenozoic shortening. Although pulses of flexural subsidence can be attributed to periods of fault reactivation (inversion) and geometrically linked thin-skinned thrusting, fully developed foreland basin conditions were only achieved in Late Cretaceous and Neogene time. Separating these two contractional episodes is an Eocene-lower Miocene (roughly 40-20 Ma) depositional hiatus within the Cenozoic succession, potentially signifying forebulge passage or neutral to

  3. Velocity and structural model of the Lower Tagus Basin according to the study of environmental seismic noise

    Science.gov (United States)

    Gomes Torres, Ricardo Jorge; Furtado, José Augusto; Gonçalves Silva, Hugo; Borges, José Fernando; Caldeira, Bento; Bezzeghoud, Mourad; Carvalho, João

    2013-04-01

    Along his history the Lower Tagus Valley (LTV) region was shaken by several earthquakes, some of them produced in large ruptures of offshore structures located southwest of the Portuguese coastline. Among these is the Lisbon earthquake of 1 November 1755 (M~8.5-8.7), and other moderates earthquakes that were produced by local sources such as the 1344 (M6.0), 1531 (M7.1) and 1909 (M6.0) earthquakes. Previous simulations [1] have shown high velocity amplification in the region. The model used in the simulations was updated from low to high resolution using all the new available geophysical and geotechnical data on the area (seismic reflection, aeromagnetic, gravimetric, deep wells and geological outcrops) [2]. To confirm this model in the areas where it was derived by potential field methods we use broadband ambient noise measurements collected in about 200 points along seven profiles on the LTV basin, six perpendicular and one parallel to the basin axis. We applied the horizontal to vertical (H/V) spectral ratio method [3] to the seismic noise profiles in order to estimate the distribution of amplification in the basin. The H/V curves obtained reveals the existence of two low frequency peaks centered on 0.2 and 1 Hz [4]. These peaks are strongly related with the thickness of Cenozoic and alluvial sediments. The velocity model obtained by inversion of the H/V curves is in good agreement with borehole data, and results obtained using seismic reflection and gravimetric methods. However, aeromagnetic data overestimates the depth of the base of Cenozoic in the areas where it overlies directly the paleozoic basement, which we attribute either to the existence of Mesozoic units or higher magnetic susceptibilities than expected for the Paleozoic. References: [1] Bezzeghoud, M., Borges, J.F., M., Caldeira (2011). Ground motion simulations of the SW Iberia margin: rupture directivity and earth structure effects. Natural Hazards, pages 1-17. doi:10.1007/s11069-011-9925-2 [2

  4. Tectonic and neotectonic implications of a new basement map of the Lower Tagus Valley, Portugal

    OpenAIRE

    Carvalho, João P. G.; Rabeh, Taha; Dias, Rui; Dias, Ruben P.; Pinto, Carlos C.; Oliveira, José Tomás; Cunha, Teresa Arriaga; Borges, José Fernando

    2014-01-01

    In this paper we present a new basement (defined here as Paleozoic, Precambrian and Mesozoic igneous rocks) map of the Lower Tagus Valley area. This map is a contribution to the understanding of the structural evolution of the top of the basement in the Lower Tagus Valley area during the Mesozoic and Cenozoic Eras. The map was produced using aeromagnetic, well, seismic reflection and geological outcrop data. It shows unprecedented details of the geometry of the basement rock's sur...

  5. Fault distribution in the Precambrian basement of South Norway

    Science.gov (United States)

    Gabrielsen, Roy H.; Nystuen, Johan Petter; Olesen, Odleiv

    2018-03-01

    Mapping of the structural pattern by remote sensing methods (Landsat, SPOT, aerial photography, potential field data) and field study of selected structural elements shows that the cratonic basement of South Norway is strongly affected by a regular lineament pattern that encompasses fault swarms of different orientation, age, style, attitude and frequency. Albeit counting numerous fault and fracture populations, the faults are not evenly distributed and N-S to NNE-SSW/NNW-SSE and NE-SE/ENE-WSW-systems are spatially dominant. N-S to NNW-SSE structures can be traced underneath the Caledonian nappes to the Western Gneiss Region in western and central South Norway, emphasizing their ancient roots. Dyke swarms of different ages are found within most of these zones. Also, the Østfold, Oslo-Trondheim and the Mandal-Molde lineament zones coincide with trends of Sveconorwegian post-collision granites. We conclude that the N-S-trend includes the most ancient structural elements, and that the trend can be traced back to the Proterozoic (Svecofennian and Sveconorwegian) orogenic events. Some of the faults may have been active in Neoproterozoic times as marginal faults of rift basins at the western margin of Baltica. Remnants of such fault activity have survived in the cores of many of the faults belonging to this system. The ancient systems of lineaments were passively overridden by the Caledonian fold-and-thrust system and remained mostly, but note entirely inactive throughout the Sub-Cambrian peneplanation and the Caledonian orogenic collapse in the Silurian-Devonian. The system was reactivated in extension from Carboniferous times, particularly in the Permian with the formation of the Oslo Rift and parts of it remain active to the Present, albeit by decreasing extension and fault activity.

  6. Gulf of California Rift Structure and Magmatism: Guaymas Basin and Comparison With Southern Basins

    Science.gov (United States)

    Lizarralde, D.; Axen, G. J.; Fletcher, J. M.; Fernandez, A. G.; Harding, A. J.; Holbrook, W. S.; Kent, G. M.; Umhoefer, P. J.; Brown, H.; Paramo, P.; Sutherland, F.

    2005-12-01

    We present a detailed seismic velocity model of the crust from margin to margin across the Guaymas Basin and compare this model with basins in the southern Gulf of California. These results are based on data from a 2002 crustal-scale, active-source seismic experiment, where multi-channel and wide-angle seismic data were acquired along three flow-line transects across Guaymas Basin, Alarcon Basin, and between Puerto Vallarta and Cabo San Lucas. Each of these transects was instrumented with ocean-bottom seismometers spaced 10-15 km apart and similarly spaced seismometers on land recording the offshore shots. The seafloor morphology of the Gulf has suggested to many that the mode of extension transitions from localized extension followed by seafloor spreading (a narrow rift) in the southern Gulf to a wide-rift mode of distributed extension in the north. This is not the case, however. The thickly sedimented Guaymas basin is a narrow rift. Lithospheric necking occurred after ~150 km of extension, and a subsequent ~300 km of extension has been accommodated by the formation of new lithosphere. The spreading center has been robustly magmatic, forming new igneous crust 7 to 10 km thick. To the south, the Alarcon basin is a wider rift, experiencing ~290 km of extension, including rift relocations, prior to the onset of seafloor spreading (~160 km of extension), which produces crust ~6 km thick. Thus, total extension for these two basins is similar (~450 km), but the mode of extension and manifestation of magmatism are very different. Differences in sedimentation may provide an explanation for the variation in magmatism between these basins, with the thicker sediments in the north providing a thermal blanket that enables more complete melt extraction from the mantle. Magmatism does not provide a sufficient explanation for the difference in rift width, however, since rifting between Cabo San Lucas and Puerto Vallarta, just one segment south of Alarcon, was particularly narrow

  7. Lithospheric structure along wide-angle seismic profile GEORIFT 2013 in Pripyat-Dnieper-Donets Basin (Belarus and Ukraine)

    Science.gov (United States)

    Starostenko, V.; Janik, T.; Yegorova, T.; Czuba, W.; Środa, P.; Lysynchuk, D.; Aizberg, R.; Garetsky, R.; Karataev, G.; Gribik, Y.; Farfuliak, L.; Kolomiyets, K.; Omelchenko, V.; Komminaho, K.; Tiira, T.; Gryn, D.; Guterch, A.; Legostaeva, O.; Thybo, H.; Tolkunov, A.

    2018-03-01

    The GEORIFT 2013 (GR'13) WARR (wide-angle reflection and refraction) experiment was carried out in 2013 in the territory of Belarus and Ukraine with broad international co-operation. The aim of the work is to study basin architecture and deep structure of the Pripyat-Dnieper-Donets Basin (PDDB), which is the deepest and best studied Palaeozoic rift basin in Europe. The PDDB is located in the southern part of the East European Craton (EEC) and crosses Sarmatia—one of the three segments of the EEC. The PDDB was formed by Late Devonian rifting associated with domal basement uplift and magmatism. The GR'13 extends in NW-SE direction along the PDDB strike and crosses the Pripyat Trough (PT) and Dnieper Graben (DG) separated by the Bragin Uplift (BU) of the basement. The field acquisition along the GR'13 (of 670 km total length) involved 14 shots and recorders deployed every ˜2.2 km for several shot points. The good quality of the data, with first arrivals visible up to 670 km for several shot points, allowed for construction of a velocity model extending to 80 km depth using ray-tracing modelling. The thickness of the sediments (Vp < 6.0 km s-1) varies from 1-4 km in the PT, to ˜5 km in the NW part of the DG, to 10-13 km in the SE part of the profile. Below the DG, at ˜330-530 km distance, we observed an upwarping of the lower crust (with Vp of ˜7.1 km s-1) to ˜25 km depth that represents a rift pillow or mantle underplate. The Moho shallows southeastwards from ˜47 km in the PT to 40-38 km in the DG with mantle velocities of 8.35 and ˜8.25 km s-1 in the PT and DG, respectively. A near-horizontal mantle discontinuity was found beneath BU (a transition zone from the PT to the DG) at the depth of 50-47 km. It dips to the depth of ˜60 km at distances of 360-405 km, similar to the intersecting EUROBRIDGE'97 profile. The crust and upper mantle structure on the GR'13 may reflect varying intensity of rifting in the PDDB from a passive stage in the PT to active rifting

  8. Tie points for Gondwana reconstructions from a structural interpretation of the Mozambique Basin, East Africa and the Riiser-Larsen Sea, Antarctica

    Directory of Open Access Journals (Sweden)

    J. Klimke

    2018-01-01

    Full Text Available Movements within early East Gondwana dispersal are poorly constrained, and there is debate about conjugate geologic structures and the timing and directions of the rifting and earliest seafloor spreading phases. We present a combined structural interpretation of multichannel reflection seismic profiles from offshore of northern Mozambique (East Africa and the conjugate Riiser-Larsen Sea (Antarctica. We find similar structural styles at the margins of both basins. At certain positions at the foot of the continental slope close to the continent–ocean transition, the basement is intensely deformed and fractured, a structural style very untypical for rifted continental margins. Sediments overlying the fractured basement are deformed and reveal toplap and onlap geometries, indicating a post-breakup deformation phase. We propose this unique deformation zone as a tie point for Gondwana reconstructions. Accordingly, we interpret the western flank of Gunnerus Ridge, Antarctica as a transform margin similar to the Davie Ridge offshore of Madagascar, implying that they are conjugate features. As the continental slope deformation is post-rift, we propose a two-phase opening scenario. A first phase of rifting and early seafloor spreading, likely in NW–SE direction, was subsequently replaced by a N–S-directed transform deformation phase overprinting the continent–ocean transition. From previously identified magnetic chrons and the sediment stratigraphy, this change in the spreading directions from NW–SE to N–S is suggested to have occurred by the late Middle Jurassic. We suggest that the second phase of deformation corresponds to the strike-slip movement of Madagascar and Antarctica and discuss implications for Gondwana breakup.

  9. An outline of neotectonic structures and morphotectonics of the western and central Pannonian basin.

    NARCIS (Netherlands)

    Fodor, L.; Bada, G.; Csillag, G.; Horvath, E.; Ruszkiczay-Rudiger, Z.; Klara, P.; Sikhegyi, F.; Timár, G.; Cloetingh, S.A.P.L.; Horvath, F.

    2005-01-01

    Neotectonic deformation in the western and central part of the Pannonian Basin was investigated by means of surface and subsurface structural analyses, and geomorphologic observations. The applied methodology includes the study of outcrops, industrial seismic profiles, digital elevation models,

  10. Structural characteristics of annual precipitation in Lake Urmia basin

    Science.gov (United States)

    Vaheddoost, Babak; Aksoy, Hafzullah

    2017-05-01

    Precipitation as the main process that brings evaporated water from the oceans to the land's surface is a critical role player in Lake Urmia basin (Iran). As a hyper-saline lake declared as UNESCO's biosphere reserve in Ramsar Convention, it is dealing with gradual atrophy. In this study, characteristics of annual precipitation in the Lake Urmia basin are investigated by means of several statistical measures and tests. Data in 53 meteorological stations widespread across the basin for a period of 31 years from 1981 to 2011 are considered for analysis. Fundamental statistical characteristics of the data like mean, maximum, minimum, standard deviation, coefficient of variation, coefficient of skewness, coefficient of kurtosis, auto-correlation and cross-correlation coefficients of the annual precipitation are calculated. Entropy in each station is also calculated with respect to the long-run mean precipitation of the basin. Results of the analysis are plotted in contour maps. Several tests for consistency, randomness, trend and best-fit probability distribution function are applied to investigate characteristics of the annual precipitation. Heterogeneity and dependence on local conditions are the main results revealed by this study while consistency and dependency of precipitation on North West and West of the basin are considered as the most effective among other regions. Due to the North-South oriented mountains, a relatively sharp decline in the precipitation from West to East can be compared to the gradual decline in precipitation from North to South due to smooth change in the terrain. It is also seen that such characteristics as probability distribution, consistency, randomness, trend, and uncertainty of annual precipitation in the Lake Urmia basin become more complex as crossing from West to East than crossing from North to South on the basin.

  11. Geophysical techniques for exploration of concealed uranium deposits in the Gwalior basin

    International Nuclear Information System (INIS)

    Choudhary, Kalpan; Singh, R.B.

    2004-01-01

    There is no direct geophysical method for the exploration of concealed uranium ore. Scope of geophysics for this in the Gwalior basin comprises delineating the basement topography, demarcation or zones of intense fracturing intersecting the unconformities and to identify the presence of carbonaceous rocks, specially in the graben-like structures. These geophysical problems have been successfully solved in other places by employing IP, resistivity, SP and gravity techniques for basement mapping, identification of fracture zone/shear zone, delineation of electrical conductors like carbonaceous rocks and sulphides. Three such case histories are presented here that include: a). basement and shear/fracture zone mapping in the Vindhyan basin north of Son-Narmada lineament, b). delineation of conductive zone (proved to be carbon phyllite) in the Mahakoshal Group of Kanhara area of Sonbhadra district, UP and c). Identification of a conductive zone, proved to be sulphide body, within the Mahakoshal group in the Gurharpahar area of Sidhi and Sonbhadra districts of MP and UP respectively. In the context of exploration for concealed uranium in the Gwalior basin, it is suggested to employ IP, resistivity, SP, gravity and magnetic methods for delineation of conductive zones like carbonaceous rocks, basement topography, including the graben like structures, fracture zone, geological boundaries and demarcation of the basin boundary. (author)

  12. NW-trending fault structures. A key factor to uranium mineralization in Egongshan volcanic basin

    International Nuclear Information System (INIS)

    Zhang Wanliang

    1996-01-01

    Influenced by the Tancheng-Lujiang fault system, the NW-trending fault structures in Egongshan basin are characterized by tensile-shearing, NE-dipping and dextrorotaty down slipping, having an obvious control over three uranium deposits and the overwhelming majority of uranium occurrences, and are the key factors to uranium mineralization. The study on the NW-trending fault structures is of practical significance in ore prospecting in Egongshan basin and other areas

  13. The Structural and Tectonic Evolution of the Arizaro Basin of the Puna Plateau in NW Argentina

    Science.gov (United States)

    Boyd, J.; Carrapa, B.; Decelles, P. G.; McNabb, J. C.; Schoenbohm, L. M.; Horton, B. K.

    2009-12-01

    The Arizaro basin is the largest basin preserved within the Puna Plateau of NW Argentina; it contains ca. 5km of Eocene-Pliocene sedimentary strata of which more than 3km are Miocene fluvial-lacustrine deposits. Previous thermochronologic and sedimentological work document that the deformation front was within the Plateau in the Eocene whereas it was within the Eastern Cordillera at the time the thickest sedimentary sequence was deposited in the Arizaro basin; therefore, the basin could be considered as intermontane. However, other processes such as the loss of mantle lithosphere and lower crust have been proposed as the cause of magmatic activity and surface uplift in the late Cenozoic, which is well documented through geophysical evidence. This opens the possibility for other basin mechanisms to contribute to basin accommodation space and deformation. Backarc extension has also been proposed. Here we present a multi-disciplinary study that addresses the contribution of two end-member mechanisms of basin formation: 1) loading and flexure within an intermontane setting; and 2) subsidence due to small scale lithospheric foundering beneath the basin. In the first case, out-of-sequence deformation and reactivation of basin bounding structures are predicted. In the latter case, radially oriented subsidence and shortening would occur during the lithospheric removal, followed by extension and basin incision. The Arizaro basin is uniquely suited to test these hypotheses because of both its location, overlying the thinnest area of the crust and lithosphere within the Plateau, and the presence of the thickest late Cenozoic section. Preliminary data was collected across the eastern side of the Salar to determine the structural style and overall pattern of deformation. Fifteen new samples were collected for low-T thermochronology and geochronology to establish the timing of tectono-thermal events in the region via apatite fission track and zircon U-Pb geochronology

  14. Chronological study of the pre-jurassic basement rocks of southern Patagonia

    International Nuclear Information System (INIS)

    Pankhurst, R.J; Rapela, C.W; Loske, W.P; Fanning, C.M

    2001-01-01

    Southern Patagonia east of the Andes was the site of extensive rhyolite volcanism during the Jurassic rifting of Gondwana and subsequent shallow marine basin formation during the Cretaceous. Thus exposures of pre-Jurassic basement are extremely sparse. Nevertheless, extraction of the maximum amount of information from these scattered outcrops of granite and metamorphic rocks is crucial to assessment of the Palaeozoic and earliest Mesozoic history and crustal structure of the Pacific margin of the supercontinent. In particular, the identification and possible correlation of early terrane accretion on this margin depends on comparison of pre-Jurassic igneous and metamorphic events with adjacent areas. This is a preliminary report on work now in progress to this end (au)

  15. Continental basement inheritance and multiscale rifted ocean margin architectures: case studies from the N Atlantic-Greenland region (Invited)

    Science.gov (United States)

    Holdsworth, R. E.; Wilson, R.; McCaffrey, K. J.; Imber, J.; Jones, R.

    2009-12-01

    It is widely believed that pre-existing basement structures significantly influence the development of rifts in both intracontinental and margin settings, but this hypothesis remains to be tested in many areas.We first investigate how fault reactivation controls the distribution and growth of individual faults in the post-breakup cover sequence of the Norwegian margin. We then use a combined onshore and offshore approach to address the wider problem of how intraplate basement structures control subsequent regional-scale fault patterns and kinematics. The influence of pre-existing, rift-related normal faults upon the early stages of fault growth in the post-breakup cover sequence is well illustrated offshore in the Vøring basin. Here Maastrichtian to Palaeocene age rift-related normal faults on the Nyk High were blanketed by Plio-Pleistocene sediments, which are cut locally by small (maximum throw directly above points of maximum throw or offsets along underlying rift-related faults, which therefore clearly control the location and architecture of later structures. Both upward and downward fault propagation from basement to cover and vice versa are recognised during this reactivation. Elastic interactions between en-echelon fault segments situated above basement heterogeneities are likely to promote the rapid growth of reactivated fault systems. Basement structures are often oriented significantly oblique to later rifting directions and can lead to transtensional deformation patterns. The Davis Strait of West Greenland contains the Ungava transform fault zone, which separates the failed spreading centres of the Labrador Sea and Baffin Bay. Detailed onshore studies of fault patterns and kinematics, at regional to outcrop scales, reveal the key roles played by two main transtensional fault systems. An older system of N-S trending en echelon normal faults bound a series of deep sedimentary basins of mid- upper-Cretaceous age that are linked by ESE-trending normal

  16. The role of pre-existing Precambrian lithospheric structures in the development of Rukwa Rift basin in the Western Branch of East African Rift System, SW Tanzania

    Science.gov (United States)

    Lemna, Obeid; Stephenson, Randell; Cornwell, David

    2017-04-01

    Continental rifts are inter-connected groups of half-grabens bordered by steep escarpments formed by border fault displacement. They often follow the pre-existing zones of weakness and/or tectonic boundaries diverging around the craton. In some areas it has been observed that border fault segmentation and rift basin asymmetry shows little or no correlation with basement structures, raising the possibility that continental rift development may in some cases at least be linked to deeper-seated lithospheric structures. The influence of pre-existing/inherited lithospheric structure remains a question for study in unravelling the evolution of continental rifts. The Rukwa Rift Basin is a northwest trending half-graben developed along the trend of the Paleoproterozoic Ubendian belt in southwest Tanzania. This belt is a linear, NW-SE trending orogenic belt in western Tanzania. It is part of a larger Paleoproterozoic orogenic belt, developed around the west and south-western margin of the Archaean Tanzanian craton. This belt is characterised by a consistent NW-trending fabric and by the presence of large shear zones that persist along the whole of the belt. As such, it offers the opportunity to examine the role of pre-existing Precambrian structures on the development of the Rukwa Rift. Digital Elevation Models (DEMs) extracted from Shuttle Radar Topography Mission (SRTM) and aeromagnetic data are used in this study. The results suggest that the orientation and geometry of Rukwa Rift basin has been influenced by the structural grains of the Paleoproterozoic Ubendian belt. Pre-existing structures within the Paleoproterozoic terrains facilitated the strain localisation within border faults that exploited the existence of inherited lithospheric heterogeneity. The southern border fault of the rift has been influenced by the NW-trending Mugese shear zone (MSZ). This shear zone has prominent NW-trending pre-existing structures in the form of transcurrent shear fabric and zones of

  17. The nature of the acoustic basement on Mendeleev and northwestern Alpha ridges, Arctic Ocean

    Science.gov (United States)

    Bruvoll, Vibeke; Kristoffersen, Yngve; Coakley, Bernard J.; Hopper, John R.; Planke, Sverre; Kandilarov, Aleksandre

    2012-01-01

    The Alpha-Mendeleev ridge complex, over 1500 km long and 250-400 km wide, is the largest submarine structure in the Arctic Ocean basin. Its origin is unknown, but often inferred to represent a large igneous province where domains of continental crust may also be a possibility. We investigate the basement geology of part of this large scale feature using 1100 km of multichannel seismic reflection data, sonobuoy recordings and marine gravity data acquired in 2005 from USCG icebreaker Healy. The sonobuoy results show top and intra-acoustic basement velocities in the range of 2.3-4.0 km/s and the seismic reflection attributes define three main acoustic facies: 1) continuous high amplitude reflections often with abrupt breaks, 3) weak wedge geometry and 3) segmented, disrupted to chaotic reflections. The acoustic characteristics and seismic velocities compare more closely with basement on Ontong Java Plateau than normal ocean crust or wedges of seaward dipping reflections at volcanic margins. The acoustic facies are interpreted to represent basalt flows and sills capping voluminous tuff deposits and possible sediments. At least two volcanic centres are identified. The upper volcanic carapace on the surveyed part of Mendeleev and northwestern Alpha ridges was emplaced during a brief igneous episode no later than Campanian (80 Ma) and most likely part of wider Late Cretaceous circum Arctic volcanism. The horst and graben morphology on Mendeleev Ridge is largely a result of post-emplacement faulting where a number of the major extensional faults remained active until a late Miocene intrusive event.

  18. Basement-cover relationships in the Grampian Caledonides of Scotland - extensional strain preceding continental rupture and generation of the Laurentian ocean-continent transition zone

    Science.gov (United States)

    Leslie, Graham; Smith, Martin; Gillespie, Martin; Thomas, Christopher; Krabbendam, Maarten

    2010-05-01

    Ancient rift and passive margin basins can frequently only be studied in outcrop after uplift following orogenesis. Such basins are thus deformed, metamorphosed and partially eroded as a consequence of closure of the oceanic system in which the passive margin was originally established. As a result there are significant challenges in restoration and interpretation of the original basin geometries and lithostratigraphical relationships. The mid-Neoproterozoic to Cambrian Dalradian Supergroup of Scotland and Ireland was intensively deformed and metamorphosed by mid-Ordovician arc-accretion (c. 460 Ma) during the Caledonian Orogeny. Nevertheless, we can determine a history of stretching and break-up associated with rupture of the Neoproterozoic supercontinent of Rodinia and opening of Iapetus. Continental fragments apparently separated from the passive margin during rift-drift transition. The extensional structures bounding the various fragments subsequently exerted control on the collisional geometry and acted as nuclei for deformation structures during Caledonian orogenesis. Reading the record of Neoproterozoic extension in the Scottish Caledonides is further complicated by the need to unravel the structural record at the boundary between the Dalradian Supergroup and underlying early-Neoproterozoic metamorphic basement. The depositional age of the Dalradian succession is not well constrained but the oldest strata could pre-date 800 Ma. If such should be the case, then the thick siliciclastic deposits characteristic of the lower Dalradian Grampian Group succession accumulated before 800 Ma during an early stretching phase (distributed high angle faulting) that led to crustal thinning (low-angle shearing). A major low-angle, regional-scale ductile shear zone in the upper levels of the underlying basement is arranged sub-parallel to the present structural base of the Dalradian. The high-temperature regional metamorphism in basement is c. 830 Ma old while the ductile

  19. Depth anomalies in the Arabian Basin, NW Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ajay, K.K.; Chaubey, A.K.

    as the difference between the observed depth to oceanic basement (corrected for sediment load) and the calculated depth to oceanic basement of the same age. The results indicate an anomalous depth to basement of oceanic crust in the Arabian Basin in the age bracket...

  20. Effects of deep basins on structural collapse during large subduction earthquakes

    Science.gov (United States)

    Marafi, Nasser A.; Eberhard, Marc O.; Berman, Jeffrey W.; Wirth, Erin A.; Frankel, Arthur

    2017-01-01

    Deep sedimentary basins are known to increase the intensity of ground motions, but this effect is implicitly considered in seismic hazard maps used in U.S. building codes. The basin amplification of ground motions from subduction earthquakes is particularly important in the Pacific Northwest, where the hazard at long periods is dominated by such earthquakes. This paper evaluates the effects of basins on spectral accelerations, ground-motion duration, spectral shape, and structural collapse using subduction earthquake recordings from basins in Japan that have similar depths as the Puget Lowland basin. For three of the Japanese basins and the Puget Lowland basin, the spectral accelerations were amplified by a factor of 2 to 4 for periods above 2.0 s. The long-duration subduction earthquakes and the effects of basins on spectral shape combined, lower the spectral accelerations at collapse for a set of building archetypes relative to other ground motions. For the hypothetical case in which these motions represent the entire hazard, the archetypes would need to increase up to 3.3 times its strength to compensate for these effects.

  1. The Upper Cretaceous to Palaeogene Sedimentary History and Tectonic Evolution of the Bala Basin, Central Anatolia, Turkey

    OpenAIRE

    Emre, Mehmet Fahrettin

    1985-01-01

    The study area is situated on the northern extension of the Tuzgolu basin, (Central Anatolia) and contains Upper Cretaceous--Tertiary volcanic, clastic, and carbonate rocks with evaporites deposited on an ophiolitic melange basement, the Ankara Melange. The present structure of the area is the result of tectonism during late Alpine movements. The movements controlled the timing and conditions of sediment accumulation. The Bala basin evolved on the northern continental margin of the Kirsehi...

  2. an investigation of basement fracture pattern in a part of ...

    African Journals Online (AJOL)

    DR ANIFOWOSE

    The basement complex of southwestern Nigeria has undergone severe tectonic deformation over the geologic past, resulting in various degrees of fracturing and folding, even to the extent of complete obliteration of primary structures except for some places. This study focuses on Akoko area which is dominated by hills of ...

  3. Exhumation of the North Alpine Foreland Basin- Quantitative insights from structural analysis, thermochronology and a new thermal history model

    Science.gov (United States)

    Luijendijk, Elco; von Hagke, Christoph; Hindle, David

    2016-04-01

    Due to a wealth of geological and thermochronology data the northern foreland basin of the European Alps is an ideal natural laboratory for understanding the dynamics of foreland basins and their interaction with surface and geodynamic processes. We present an unprecedented compilation of thermochronological data from the basin and quantify cooling and exhumation rates in the basin by combining published and new vitrinite reflectance, apatite fission track and U-Th/He data with a new inverse burial and thermal history model. No correlation is obvious between inferred cooling and exhumation rates and elevation, relief or tectonics. We compare derived temperature histories to exhumation estimates based on the retro-deformation of Molasse basin and the Jura mountains, and to exhumation caused by drainage reorganization and incision. Drainage reorganization can explain at most 25% of the observed cooling rates in the basin. Tectonic transport of the basin's sediments over the inclined basement of the alpine foreland as the Jura mountains shortened can explain part of the cooling signal in the western part of the basin. However, overall a substantial amount of cooling and exhumation remains unexplained by known tectonic and surface processes. Our results document basin wide exhumation that may be related to slab roll-back or other lithospheric processes. Uncertainty analysis shows that thermochronometers can be explained by cooling and exhumation starting as early as the Miocene or as late as the Pleistocene. New (U-Th)/He data from key areas close to the Alpine front may provide better constraints on the timing of exhumation.

  4. 2D Seismic Velocity Modelling in the Southeastern Romanian Carpathians and its Foreland (Vrancea Zone and Focsani Basin)

    Science.gov (United States)

    Stephenson, R.; Bocin, A.; Tryggvason, A.

    2003-12-01

    The DACIA-PLAN (Danube and Carpathian Integrated Action on Processes in the Lithosphere and Neotectonics) deep seismic reflection survey was performed in August-September 2001, with the objective of obtaining of new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea Zone, including the rapidly subsiding Focsani Basin. The DACIA-PLAN profile is about 140 km long, having a roughly NW-SE direction, from near the southeast Transylvanian Basin, across the mountainous southeastern Carpathians and their foreland to near the Danube Dalta. A high resolution 2D velocity model of the upper crust along the seismic profile has been determined from a first-arrival tomographic inversion of the DACIA-PLAN data. The shallowing of Palaeozoic-Mesozoic basement, and related structural heterogeneity within it, beneath the eastern flank of the Focsani Basin is clearly seen. Velocity heterogeneity within the Carpathian nappe belt is also evident and is indicative of internal structural complexity, including the presence of salt bodies and basement involvement in thrusting, thus favouring some current geological models over others. The presence of basement involvement implies the compressional reactivation of pre-existing basement normal faults. Members of the DACIA-PLAN/TomoSeis Working Group (see poster) should be considered as co-authors of this presentation.

  5. OPENING STRUCTURE OF THE BONE BASIN ON SOUTH SULAWESI IN RELATION TO PROCESS OF SEDIMENTATION

    Directory of Open Access Journals (Sweden)

    Lili Sarmili

    2017-07-01

    Full Text Available Sulawesi Island is situated on the three major plates, namely the Indo-Australian plate together with Continent Australia (Australian Craton plate moves towards the North - Northeast and crust Pacific - Philippines moves towards the West - Northwest, causing the collision with the Eurasian plate (Sunda Land which more passive or stable. The Bone basin is located between South Sulawesi and Southeast Sulawesi arms. This basin is formed by several fault system, such as, Walanae, Palukoro, West and East Bone faults and others. Several active faults are likely to be extended each other into the openings structure and characterized by the accumulation of young sediment in the Bone basin.

  6. Genetic structure of lake whitefish, Coregonus clupeaformis, populations in the northern main basin of Lake Huron

    Science.gov (United States)

    Stott, Wendylee; Ebener, Mark P.; Mohr, Lloyd; Schaeffer, Jeff; Roseman, Edward F.; Harford, William J.; Johnson, James E.; Fietsch, Cherie-Lee

    2012-01-01

    Genetic analysis of spawning lake whitefish (Coregonus clupeaformis) from six sites in the main basin of Lake Huron was conducted to determine population structure. Samples from fisheryindependent assessment surveys in the northwest main basin were analyzed to determine the relative contributions of lake whitefish genetic populations. Genetic population structure was identified using data from seven microsatellite DNA loci. One population was identified at Manitoulin Island, one to two were observed in the east-central main basin (Fishing Island and Douglas Point), and one to two populations were found in the northwest (Thunder Bay and Duncan Bay). The genetic identity of collections from Duncan Bay and Thunder Bay was not consistent among methods used to analyze population structure. Low genetic distances suggested that they comprised one population, but genic differences indicated that they may constitute separate populations. Simulated data indicated that the genetic origins of samples from a mixed-fishery could be accurately identified, but accuracy could be improved by incorporating additional microsatellite loci. Mixture analysis and individual assignment tests performed on mixed-stock samples collected from the western main basin suggested that genetic populations from the east-central main basin contributed less than those from the western main basin and that the proportional contribution of each baseline population was similar in each assessment sample. Analysis of additional microsatellite DNA loci may be useful to help improve the precision of the estimates, thus increasing our ability to manage and protect this valuable resource.

  7. Basement Membrane Defects in Genetic Kidney Diseases

    Directory of Open Access Journals (Sweden)

    Christine Chew

    2018-01-01

    Full Text Available The glomerular basement membrane (GBM is a specialized structure with a significant role in maintaining the glomerular filtration barrier. This GBM is formed from the fusion of two basement membranes during development and its function in the filtration barrier is achieved by key extracellular matrix components including type IV collagen, laminins, nidogens, and heparan sulfate proteoglycans. The characteristics of specific matrix isoforms such as laminin-521 (α5β2γ1 and the α3α4α5 chain of type IV collagen are essential for the formation of a mature GBM and the restricted tissue distribution of these isoforms makes the GBM a unique structure. Detailed investigation of the GBM has been driven by the identification of inherited abnormalities in matrix proteins and the need to understand pathogenic mechanisms causing severe glomerular disease. A well-described hereditary GBM disease is Alport syndrome, associated with a progressive glomerular disease, hearing loss, and lens defects due to mutations in the genes COL4A3, COL4A4, or COL4A5. Other proteins associated with inherited diseases of the GBM include laminin β2 in Pierson syndrome and LMX1B in nail patella syndrome. The knowledge of these genetic mutations associated with GBM defects has enhanced our understanding of cell–matrix signaling pathways affected in glomerular disease. This review will address current knowledge of GBM-associated abnormalities and related signaling pathways, as well as discussing the advances toward disease-targeted therapies for patients with glomerular disease.

  8. TECTONIC ZONING OF THE SEDIMENTARY COVER IN THE DERYUGIN BASIN OF THE SEA OF OKHOTSK BASED ON STRUCTURAL-MATERIAL (LITHOPHYSICAL INDICATORS

    Directory of Open Access Journals (Sweden)

    V. P. Semakin

    2013-01-01

    Full Text Available In terms of tectonics, the Deryugin basin (Fig. 1 is a part of the epi-Mesozoic Okhotsk plate comprising the heterogeneous basement that is mainly pre-Cenozoic (the lower structural stage and the sedimentary cover that is mainly represented by the Paleogenic-Neogenic-Quaternary deposits with the Upper Cretaceous sedimentary rocks observed locally without a visible hiatus (the upper structural stage.The acoustic basement (AB is composed of the metamorphosed Upper Cretaceous-Paleogenic silty-clayey-siliceous deposits (the western part of the region, amphibolites, gneisses, crystalline schists, weakly metamorphosed sandstones, siltstones, and mudstones (often siliceous, as well as intrusive and effusive rocks of basic, intermediate, and rarely persilic composition (the eastern part of the region. AB is generally dated as Mesozoic–Paleozoic.Results of tectonic zoning of the sedimentary cover based on material (lithophysical indicators (Fig. 2 are represented in the format of maps showing lithophysical complexes (LC within the limits of four regional seismo-stratigraphic complexes/structural layers (RSSC I-IV corresponding to the following time intervals: the pre-Oligocene К2–P1-2 (RSSC I, the Oligocene – Lower Miocene P3–N11 (RSSC II, the Lower – Mid Miocene N11–2 (RSSC III, and the Upper Miocene – Pliocene N13–N2 (RSSC IV. Diverse lithological-facies associations composing the RSSCs are grouped into the following lithophysical complexes (LC: 1 - coal-bearing silty-clayey-sandy terrigenous, 2 - sandy-silty-clayey terrigenous, 3 - silty-clayey-siliceous, and 4 - sandy-silty-clayey volcanic [Sergeyev, 2006]. In the studied area (Fig. 2, the deposits of the pre-Oligocene RSSC are identified in limited areas within its northern, northwestern, and southwestern parts; they are represented by coal-bearing silty-clayey-sandy terrigenous and silty-clayey-siliceous LCs. Other RSSCs (II, III, and IV in this area represented mostly by sandy

  9. Geochemical interpretation of the Precambrian basement and overlying Cambrian sandstone on Bornholm, Denmark: Implications for the weathering history

    Science.gov (United States)

    Zhou, Lingli; Friis, Henrik; Yang, Tian; Nielsen, Arne Thorshøj

    2017-08-01

    Borggård borehole (CIA = 52-69, PIA = 56-99) and an outcrop in Nexø, eastern Bornholm (CIA = 52-66, PIA = 61-96), have endured similar degrees of weak to moderate weathering but lost most of the plagioclase. The LSF has a comparable weathering history (CIA = 63-73), but the plagioclase is better preserved (PIA = 65-78). The significant variation of weathering rates of plagioclase and K-feldspar in the basement granite and the provenance of sandstone from the Borggård borehole are likely due to the different permeability developed within the internal crystal structures, a Ca- rich plagioclase original composition of the plagioclase, and the occurrence of weathering in a very humid climate. ​K metasomatism occurred in the basement granite and sandstone in both the Borggård and the G14-1 boreholes, mainly through the conversion of aluminous clay minerals (e.g. kaolinite) to illite, with transformation of plagioclase to K-feldspar occurring locally. This my have taken place during deep burial in the Caledonian foreland basin.

  10. Structure and composition of the liana assemblage of a mixed rainforest in the Congo Basin

    NARCIS (Netherlands)

    Ewango, C.E.N.; Bongers, F.; Makana, J.R.; Poorter, L.; Sosef, M.S.M.

    2015-01-01

    Background and aims – The Congo Basin lowland forest represents one of the largest tropical forest blocks in the world, but its liana assemblage has never been characterized. We evaluate liana floristics, diversity, and structure in the Ituri Forest, and determine the effects of forest structure and

  11. The Acinar Cage: Basement Membranes Determine Molecule Exchange and Mechanical Stability of Human Breast Cell Acini.

    Directory of Open Access Journals (Sweden)

    Aljona Gaiko-Shcherbak

    Full Text Available The biophysical properties of the basement membrane that surrounds human breast glands are poorly understood, but are thought to be decisive for normal organ function and malignancy. Here, we characterize the breast gland basement membrane with a focus on molecule permeation and mechanical stability, both crucial for organ function. We used well-established and nature-mimicking MCF10A acini as 3D cell model for human breast glands, with ether low- or highly-developed basement membrane scaffolds. Semi-quantitative dextran tracer (3 to 40 kDa experiments allowed us to investigate the basement membrane scaffold as a molecule diffusion barrier in human breast acini in vitro. We demonstrated that molecule permeation correlated positively with macromolecule size and intriguingly also with basement membrane development state, revealing a pore size of at least 9 nm. Notably, an intact collagen IV mesh proved to be essential for this permeation function. Furthermore, we performed ultra-sensitive atomic force microscopy to quantify the response of native breast acini and of decellularized basement membrane shells against mechanical indentation. We found a clear correlation between increasing acinar force resistance and basement membrane formation stage. Most important native acini with highly-developed basement membranes as well as cell-free basement membrane shells could both withstand physiologically relevant loads (≤ 20 nN without loss of structural integrity. In contrast, low-developed basement membranes were significantly softer and more fragile. In conclusion, our study emphasizes the key role of the basement membrane as conductor of acinar molecule influx and mechanical stability of human breast glands, which are fundamental for normal organ function.

  12. Evaluation of genetic population structure of smallmouth bass in the Susquehanna River basin, Pennsylvania

    Science.gov (United States)

    Schall, Megan K.; Bartron, Meredith L.; Wertz, Timothy; Niles, Jonathan M.; Shaw, Cassidy H.; Wagner, Tyler

    2017-01-01

    The Smallmouth Bass Micropterus dolomieu was introduced into the Susquehanna River basin, Pennsylvania, nearly 150 years ago. Since introduction, it has become an economically and ecologically important species that supports popular recreational fisheries. It is also one of the most abundant top predators in the system. Currently, there is no information on the level of genetic diversity or genetic structuring that may have occurred since introduction. An understanding of genetic diversity is important for the delineation of management units and investigation of gene flow at various management scales. The goals of this research were to investigate population genetic structure of Smallmouth Bass at sites within the Susquehanna River basin and to assess genetic differentiation relative to Smallmouth Bass at an out-of-basin site (Allegheny River, Pennsylvania) located within the species’ native range. During spring 2015, fin clips (n = 1,034) were collected from adults at 11 river sites and 13 tributary sites in the Susquehanna River basin and at one site on the Allegheny River. Fin clips were genotyped at 12 polymorphic microsatellite loci. Based on our results, adults sampled throughout the Susquehanna River basin did not represent separate genetic populations. There were only subtle differences in genetic diversity among sites (mean pairwise genetic differentiation index FST = 0.012), and there was an overall lack of population differentiation (K = 3 admixed populations). The greatest genetic differentiation was observed between fish collected from the out-of-basin site and those from the Susquehanna River basin sites. Knowledge that separate genetic populations of Smallmouth Bass do not exist in the Susquehanna River basin is valuable information for fisheries management in addition to providing baseline genetic data on an introduced sport fish population.

  13. Review and prospect on the botryoidal structures from the Sinian Dengying Formation, Sichuan Basin, China

    Directory of Open Access Journals (Sweden)

    Chengbo Lian

    2017-06-01

    Full Text Available Fabric of carbonate rock is the important foundation and one of main research contents for study on carbonate sedimentology, and has always been the attention of the academic circles. Botryoidal structures from the Sinian Dengying Formation in the Sichuan Basin is a kind of special carbonate fabric, the fabric is named after the shape of a grape. In this paper, from four aspects of the research status, the definition of the botryoidal structures and the related terms, the construction characteristics of the botryoidal structures, the component of the botryoidal structures, geochemical characteristics and the genesis of the botryoidal structures are reviewed. It points out the current research issues of botryoidal structures from the Sinian Dengying Formation in the Sichuan Basin, and put forward that future research should focus on the accurate analysis of its internal construction, precipitation mechanism of the major components, and the construction mechanism of botryoidal structures.

  14. cDNA cloning of the basement membrane chondroitin sulfate proteoglycan core protein, bamacan: a five domain structure including coiled-coil motifs

    DEFF Research Database (Denmark)

    Wu, R R; Couchman, J R

    1997-01-01

    obtained cDNA clones encoding the entire bamacan core protein of Mr = 138 kD, which reveal a five domain, head-rod-tail configuration. The head and tail are potentially globular, while the central large rod probably forms coiled-coil structures, with one large central and several very short interruptions....... The protein sequence has low overall homology, apart from very small NH2- and COOH-terminal motifs. At the junctions between the distal globular domains and the coiled-coil regions lie glycosylation sites, with up to three N-linked oligosaccharides and probably three chondroitin chains. Three other Ser...

  15. New K-Ar constraints on the onset of subsidence in the Canning Basin, Western Australia

    International Nuclear Information System (INIS)

    Shaw, R.D.; Tyler, I.M.; Griffin, T.J.; Webb, A.

    1992-01-01

    Structural mapping and reconnaissance K-Ar studies have helped to delineate and date the latest deformational stages (D4 and D5) in the King Leopold Orogen, to the north of the Canning Basin. The dates have been determined for schists selected from both contractional shear zones and from rocks metamorphosed to the lower greenschist facies during the final phase of basement deformation. These dates imply that the basement-deforming event started in the latest Precambrian to earliest Cambrian (ca 560 Ma), and that tectonism recurred in the latest Cambrian to earliest Ordovician (ca 500 Ma). The final contractional deformation is slightly older than the oldest-known sedimentary rocks in the basin (latest Tremadoc), and helps to define the time that basin subsidence started. 23 refs., 3 tabs., 2 figs

  16. Structural aspects of the atmospheric aerosol of the Amazon basin

    International Nuclear Information System (INIS)

    Artaxo Netto, P.E.; Orsini, C.M.Q.

    1982-01-01

    The results presented on this paper may be considered as complementary to the ones published on two previous papers about the natural atmospheric aerosol of the Amazon Basin, and the effects, on these physical-chemical systems of the large scale brushfires carried out from time to time on that region. The experiments have been performed in August-September, 1980, simultaneously to the ones of the 'Projeto Queimadas - 1980' promoted by the National Center for Atmospheric Research from the U.S.A.. The new results here in presented are size distribution concentration data as log-probability curves for the detected tracer-elements; from these curves, by introducing a new technique, is was possible to derive the corresponding log-normal curves. These last curves can be used conveniently to characterize the atmospheric aerosol system which is under investigation. (Author) [pt

  17. Pre-impact tectonothermal evolution of the crystalline basement-derived rocks in the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure

    Science.gov (United States)

    Gibson, R.L.; Townsend, G.N.; Horton, J. Wright; Reimold, W.U.

    2009-01-01

    Pre-impact crystalline rocks of the lowermost 215 m of the Eyreville B drill core from the Chesapeake Bay impact structure consist of a sequence of pelitic mica schists with subsidiary metagraywackes or felsic metavolcanic rocks, amphibolite, and calc-silicate rock that is intruded by muscovite (??biotite, garnet) granite and granite pegmatite. The schists are commonly graphitic and pyritic and locally contain plagioclase porphyroblasts, fi brolitic sillimanite, and garnet that indicate middle- to upper-amphibolite-facies peak metamorphic conditions estimated at ??0.4-0.5 GPa and 600-670 ??C. The schists display an intense, shallowly dipping, S1 composite shear foliation with local micrometer- to decimeter-scale recumbent folds and S-C' shear band structures that formed at high temperatures. Zones of chaotically oriented foliation, resembling breccias but showing no signs of retrogression, are developed locally and are interpreted as shear-disrupted fold hinges. Mineral textural relations in the mica schists indicate that the metamorphic peak was attained during D1. Fabric analysis indicates, however, that subhorizontal shear deformation continued during retrograde cooling, forming mylonite zones in which high-temperature shear fabrics (S-C and S-C') are overprinted by progressively lower- temperature fabrics. Cataclasites and carbonate-cemented breccias in more competent lithologies such as the calc-silicate unit and in the felsic gneiss found as boulders in the overlying impactite succession may refl ect a fi nal pulse of low-temperature cataclastic deformation during D1. These breccias and the shear and mylonitic foliations are cut by smaller, steeply inclined anastomosing fractures with chlorite and calcite infill (interpreted as D2). This D2 event was accompanied by extensive chlorite-sericitecalcite ?? epidote retrogression and appears to predate the impact event. Granite and granite pegmatite veins display local discordance to the S1 foliation, but elsewhere

  18. A study of tectonic activity in the Basin-Range Province and on the San Andreas Fault. No. 2: Lithospheric structure, seismicity, and contemporary deformation of the United States Cordillera

    Science.gov (United States)

    Smith, R. B.

    1986-01-01

    The structural evolution of the U.S. Cordillera has been influenced by a variety of tectonic mechanisms including passive margin rifting and sedimentation; arc volcanism; accretion of exotic terranes; intraplate magmatism; and folding and faulting associated with compression and extension processes that have profoundly influenced the lithospheric structure. As a result the Cordilleran crust is laterally inhomogeneous across its 2000 km east-west breadth. It is thin along the West Coast where it has close oceanic affinities. The crust thickens eastward beneath the Sierra Nevada, then thins beneath the Basin-Range. Crustal thickening continues eastward beneath the Colorado Plateau, the Rocky Mountains, and the Great Plains. The total lithospheric thickness attains 65 km in the Basin-Range and increases eastward beneath the Colorado Plateau. The upper-crust, including the crystalline basement of the Cordillera, has P sub G velocities of 6 km/s in the Basin-Range and Rio Grande Rift. Lower P sub G velocities of 5.4 to 5.7 km/s are associated with the youthful Yellowstone, Valles and Long Valley calderas and the Franciscan assemblage of the western coastal margin. Averaged crustal velocity reflects integrated tectonic evolution of the crust-thick silicic bodies, velocity reversals, and a thin crust produce low averaged velocities that are characteristic of a highly attenuated and thermally deformed crust.

  19. Deep structure of the continental margin and basin off Greater Kabylia, Algeria - New insights from wide-angle seismic data modeling and multichannel seismic interpretation

    Science.gov (United States)

    Aïdi, Chafik; Beslier, Marie-Odile; Yelles-Chaouche, Abdel Karim; Klingelhoefer, Frauke; Bracene, Rabah; Galve, Audrey; Bounif, Abdallah; Schenini, Laure; Hamai, Lamine; Schnurle, Philippe; Djellit, Hamou; Sage, Françoise; Charvis, Philippe; Déverchère, Jacques

    2018-03-01

    During the Algerian-French SPIRAL survey aimed at investigating the deep structure of the Algerian margin and basin, two coincident wide-angle and reflection seismic profiles were acquired in central Algeria, offshore Greater Kabylia, together with gravimetric, bathymetric and magnetic data. This 260 km-long offshore-onshore profile spans the Balearic basin, the central Algerian margin and the Greater Kabylia block up to the southward limit of the internal zones onshore. Results are obtained from modeling and interpretation of the combined data sets. The Algerian basin offshore Greater Kabylia is floored by a thin oceanic crust ( 4 km) with P-wave velocities ranging between 5.2 and 6.8 km/s. In the northern Hannibal High region, the atypical 3-layer crustal structure is interpreted as volcanic products stacked over a thin crust similar to that bordering the margin and related to Miocene post-accretion volcanism. These results support a two-step back-arc opening of the west-Algerian basin, comprising oceanic crust accretion during the first southward stage, and a magmatic and probably tectonic reworking of this young oceanic basement during the second, westward, opening phase. The structure of the central Algerian margin is that of a narrow ( 70 km), magma-poor rifted margin, with a wider zone of distal thinned continental crust than on the other margin segments. There is no evidence for mantle exhumation in the sharp ocean-continent transition, but transcurrent movements during the second opening phase may have changed its initial geometry. The Plio-Quaternary inversion of the margin related to ongoing convergence between Africa and Eurasia is expressed by a blind thrust system under the margin rising toward the surface at the slope toe, and by an isostatic disequilibrium resulting from opposite flexures of two plates decoupled at the continental slope. This disequilibrium is likely responsible for the peculiar asymmetrical shape of the crustal neck that may thus

  20. Structural evolution of the Kilombero rift basin in central Tanzania ...

    African Journals Online (AJOL)

    Detailed geological and structural investigations at the northwestern scarp of the Cenozoic Kilombero Rift allow the drawing of its structural evolution and establishment of stress conditions that prevailed at the different deformational episodes at this rift zone. The structure, where the northwestern scarp of the Cenozoic ...

  1. Deep structure of Porcupine Basin and nature of the Porcupine Median Ridge from seismic refraction tomography

    Science.gov (United States)

    Watremez, L.; Chen, C.; Prada, M.; Minshull, T. A.; O'Reilly, B.; Reston, T. J.; Wagner, G.; Gaw, V.; Klaeschen, D.; Shannon, P.

    2015-12-01

    The Porcupine Basin is a narrow V-shaped failed rifted basin located offshore SW Ireland. It is of Permo-Triassic to Cenozoic age, with the main rifting phase in the Late Jurassic to Early Cretaceous. Porcupine Basin is a key study area to learn about the processes of continental extension and to understand the thermal history of this rifted basin. Previous studies show increasing stretching factors, from less than 1.5 to the North to more than 6 to the South. A ridge feature, the Porcupine Median Ridge, has been identified in the middle of the southernmost part of the basin. During the last three decades, this ridge has been successively interpreted as a volcanic structure, a diapir of partially serpentinized mantle, or a block of continental crust. Its nature still remains debated today. In this study, we use arrival times from refractions and wide-angle reflections in the sedimentary, crustal and mantle layers to image the crustal structure of the thinnest part of the basin, the geometry of the continental thinning from margin to margin, and the Porcupine Median Ridge. The final velocity model is then compared with coincident seismic reflection data. We show that (1) the basin is asymmetric, (2) P-wave velocities in the uppermost mantle are lower than expected for unaltered peridotites, implying upper-mantle serpentinisation, (3) the nature of Porcupine Median Ridge is probably volcanic, and (4) the amount of thinning is greater than shown in previous studies. We discuss the thermal implications of these results for the evolution of this rift system and the processes leading to the formation of failed rifts. This project is funded by the Irish Shelf Petroleum Studies Group (ISPSG) of the Irish Petroleum Infrastructure Programme Group 4.

  2. Plate interior polyphase fault systems and sedimentary basin evolution: A case study of the East Gobi Basin and East Gobi Fault Zone, southeastern Mongolia

    Science.gov (United States)

    Heumann, Matthew J.; Johnson, Cari L.; Webb, Laura E.

    2018-01-01

    Structural interpretation of 2-D seismic reflection data and subsurface-outcrop correlations reveal six distinct phases of deformation recorded in the Paleozoic basement rocks and Mesozoic-Cenozoic basin fill of the East Gobi Basin (EGB), southeastern Mongolia. These phases include arc accretion and arc-continent collision in late Paleozoic time, Late Triassic sinistral shear-zone development, Early Jurassic fold and thrust belt style shortening, Middle Jurassic-Lower Cretaceous extension and rift basin development, middle Cretaceous shortening with basin inversion and regional unconformity development, and Late Cretaceous-Oligocene thermal subsidence with renewed Paleogene left-lateral strike slip faulting across the fault zone. The five post-amalgamation deformation phases are localized along the East Gobi Fault Zone, suggesting that preexisting structures and boundary conditions exert fundamental controls on the long term evolution of intracontinental basins such as the EGB. Subsurface geophysical data and outcrop correlations demonstrate that the main subbasins of the EGB contain major differences in basement metamorphic and structural fabrics, basin fill patterns, and distinct Mesozoic-Cenozoic fault generations. Potential causes related to far-field boundary conditions and other driving factors are suggested for each of the major deformation phases.

  3. 3D basin structure of the Santa Clara Valley constrained by ambient noise tomography

    Science.gov (United States)

    Cho, H.; Lee, S. J.; Rhie, J.; Kim, S.

    2017-12-01

    The basin structure is an important factor controls the intensity and duration of ground shaking due to earthquake. Thus it is important to study the basin structure for better understanding seismic hazard and also improving the earthquake preparedness. An active source seismic survey is the most appropriate method to determine the basin structure in detail but its applicability, especially in urban areas, is limited. In this study, we tested the potential of an ambient noise tomography, which can be a cheaper and more easily applicable method compared to a traditional active source survey, to construct the velocity model of the basin. Our testing region is the Santa Clara Valley, which is one of the major urban sedimentary basins in the States. We selected this region because continuous seismic recordings and well defined velocity models are available. Continuous seismic recordings of 6 months from short-period array of Santa Clara Valley Seismic Experiment are cross-correlated with 1 hour time window. And the fast marching method and the subspace method are jointly applied to construct 2-D group velocity maps between 0.2 - 4.0 Hz. Then, shear wave velocity model of the Santa Clara Valley is calculated up to 5 km depth using bayesian inversion technique. Although our model cannot depict the detailed structures, it is roughly comparable with the velocity model of the US Geological Survey, which is constrained by active seismic surveys and field researches. This result indicate that an ambient noise tomography can be a replacement, at least in part, of an active seismic survey to construct the velocity model of the basin.

  4. Along-axis crustal structure of the Porcupine Basin from seismic refraction data modelling

    Science.gov (United States)

    Prada, Manel; Watremez, Louise; Chen, Chen; O'Reilly, Brian; Minshull, Tim; Reston, Tim; Wagner, Gerlind; Gaws, Viola; Klaschen, Dirk; Shannon, Patrick

    2016-04-01

    The Porcupine Basin is a tongue-shaped offshore basin SW of Ireland that formed during the opening of the North Atlantic Ocean. Its history of development involved several rifting and subsidence phases during the Late Paleozoic and Cenozoic, with a particular major rift phase occurring in Late Jurassic-Early Cretaceous times. Previous work, focused on subsidence analysis, showed that stretching factors (β) in the northern part of the basin are 6. However, recent studies based on seismic reflection and refraction profiles concluded that β in places along the basin axis were significantly higher, and suggested the presence of major crustal faulting and uppermost mantle serpentinization in the basin. Constraining β and the processes related to the formation of the basin will provide insights into aspects such as the tectonic response to lithospheric extension and the thermal evolution of the basin. Here we present the tomography results of five wide-angle seismic (WAS) profiles acquired across and along the basin axis. We used a travel time inversion method to model the WAS data and obtain P-wave velocity (Vp) models of the crust and uppermost mantle, together with the geometry of the main geological interfaces along each of these lines. Coincident seismic reflection profiles to each WAS line were also used to integrate the tectonic structure with the Vp model. These results improved constrains on the location of the base of the crust and allow to estimate maximum β (βmax) along each profile. The analysis shows that βmax values in the northern part of the basin are 5-6 times larger than estimates based on subsidence analysis. Towards the south, βmax increases up to 10, but then rapidly decreases to 3.3 southwards. These values are well within the range of crustal extension at which the crust becomes entirely brittle at magma-poor margins allowing the formation of major crustal faulting and serpentinization of the mantle. In agreement with this observation, Vp

  5. Exploration of underground basement structures in Kanto plain using the spatial autocorrelation method. 1. S-wave velocity structure along the line from Hatoyama, Saitama to Noda, Chiba; Kukan jiko sokanho ni yoru Kanto heiya no kiban kozo tansa. 1. Saitamaken Hatoyama machi - Chibaken Nodashi kan no S ha sokudo kozo

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, T.; Umezawa, N.; Shiraishi, H. [Saitama Institute of Environmental Pollution, Saitama (Japan)

    1997-05-27

    The Saitama prefectural government has been conducting basement structure exploration using the spatial autocorrelation method by dividing the entire plain area into meshes, for the purpose of improving the accuracy of estimating large-scale seismic damages. This paper reports the result of explorations on meshes in the east-west direction in the central part of Saitama Prefecture. The present exploration was intended on ten meshes in the east-west direction along the north latitude 36-degree line. The number of exploration points is 13 comprising three points on the hilly area bordering on the eastern edge of the Kanto mountainous area and ten points on the plain area. The arrangement constitutes a traverse line with a total distance of about 33 km from the west edge (Hatoyama-machi in Saitama Prefecture) to the east edge (Noda City in Chiba Prefecture). The phase velocities were estimated from the result of the array microtremor observations using the spatial autocorrelation method applied with the FET. The phase velocities were used to estimate underground structures by using an inverse analysis. As a result, detailed two-dimensional S-wave velocity structures were revealed on the traverse line. The velocity cross section expresses change in the basement structures with sufficient resolution, and at the same time the information is judged highly harmonious with existing deep boring data and the result of artificial earthquake exploration. 15 refs., 6 figs.

  6. Slump structures in quaternary slope sediments of the northern Derbent Basin (Caspian Sea)

    Science.gov (United States)

    Verzhbitskii, V. E.; Lobkovskii, L. I.; Roslyakov, A. G.; Merklin, L. R.; Polyakov, A. S.; Levchenko, O. V.; Kovachev, S. A.; Zverev, A. S.; Garagash, I. A.; Mar, G. N.; Mutovkin, A. D.; Putans, V. A.; Libina, N. V.; Soltanovskii, I. I.; Slobodyan, V. Yu.; Gontarev, S. V.

    2009-06-01

    During Cruise 20-3 of the R/V Rift (April, 2006), the area that includes the shelf and slope of the Derbent Basin in the northern Middle Caspian was studied using the continuous seismoacoustic profiling method. In accordance with the previous standpoint, two Pleistocene deltaic complexes formed in the Enotaevian and Mangyshlakian time are defined in this area. The seismoacoustic records obtained for the northern slope of the Derbent Basin demonstrate the development of specific rootless exogenic-gravitational fold structures in the upper (˜150-200 m) Quaternary part of the sedimentary sequence. The Quaternary section encloses angular unconformities indicating the pulsating mode of gravitational processes in the northern slope of the basin. South-dipping gravitational normal faults (and/or normal fault-related flexures) displacing the bottom surface and uppermost sedimentary layers (with vertical amplitudes up to 5-6 m) were defined in the southern part of the study area. Several impulses of the submarine slump structures predated and accompanied the deposition of the upper deltaic sequence (Mangyshlakian), although their most intense formation took place later during the Novocaspian (Holocene) time. Thus, the structural analysis of the seismoacoustic data revealed intense development of different-origin and different-age gravitational structures within the Quaternary sediments in the northern slope of the Derbent Basin. These results should be taken into consideration when designing, building, and operating submarine constructions in order to prevent potential natural hazards and reduce their consequences.

  7. Crustal structure and rift tectonics across the Cauvery–Palar basin ...

    Indian Academy of Sciences (India)

    India from subsidence modelling; Mar. Petrol. Geol. 12. 667–675. Curray J R, Emmel F J, Moore D G and Raitt R W 1982. Structure, tectonics and geological history of the north- eastern Indian Ocean; In: The Ocean Basins and Margins: The Indian Ocean (eds) Nairn A E M and Stehli F G, 6,. Plenum Press, New York, pp.

  8. Applicability of the spatial autocorrection method for estimation of basement structure in Kanto plain. Array measurements of microtremors close to the Iwatsuki and Shimosa deep borehole observatory; Kanto heiya no kiban kozo suitei no tame no kukan jiko sokanho no tekiyosei. Iwatsuki Shimosa jiban katsudo kansokusei ni okeru array bido kansoku

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, T.; Umezawa, N.; Shiraishi, H. [Saitama Institute of Environmental Pollution, Saitama (Japan)

    1996-10-01

    To investigate applicability of the spatial autocorrection method which is a microtremors exploration method for the estimation of basement structure, array measurements of microtremors were performed using the Iwatsuki and Shimosa deep borehole observatory where detailed structures were clarified as well as the Fuchu and Koto deep borehole observatory. In this study, estimated velocity structures of S-wave were compared with the geological sequence and results of acoustic velocity logging. The phase velocity was estimated by the spatial autocorrection method using FFT. The phase velocity with a smooth normal dispersion was observed in the periodic range from 0.5 to 5 sec in Iwatsuki, and from 0.5 to 4 sec in Shimosa by the combination of four-point circular arrays with radii of 100, 300, and 600 m. The underground structures estimated from the phase velocities coincided well with the geological sequence, and results of acoustic velocity logging and velocity logging for each borehole. For the Iwatsuki borehole, the basement velocity was also estimated properly in the periodic range of observation. While, for the Shimosa borehole, measurements with the period around 6 sec were required to estimate the basement velocity more accurately. 13 refs., 11 figs., 1 tab.

  9. Lithological and structural controls on the development of aquifer in ...

    African Journals Online (AJOL)

    Lithological and structural controls on the development of aquifers in low-grade Neoproterozoic rocks in Tsalit–Ira River Basin, northern Ethiopia are discussed in this paper. Metavolcanic and metasedimentary rocks represent the low grade basement rocks and are overlain by younger sedimentary and volcanic rocks.

  10. Impact of structural and autocyclic basin-floor topography on the depositional evolution of the deep-water Valparaiso forearc basin, central Chile

    Science.gov (United States)

    Laursen, J.; Normark, W.R.

    2003-01-01

    The Valparaiso Basin constitutes a unique and prominent deep-water forearc basin underlying a 40-km by 60-km mid-slope terrace at 2.5-km water depth on the central Chile margin. Seismic-reflection data, collected as part of the CONDOR investigation, image a 3-3.5-km thick sediment succession that fills a smoothly sagged, margin-parallel, elongated trough at the base of the upper slope. In response to underthrusting of the Juan Ferna??ndez Ridge on the Nazca plate, the basin fill is increasingly deformed in the seaward direction above seaward-vergent outer forearc compressional highs. Syn-depositional growth of a large, margin-parallel monoclinal high in conjunction with sagging of the inner trough of the basin created stratal geometries similar to those observed in forearc basins bordered by large accretionary prisms. Margin-parallel compressional ridges diverted turbidity currents along the basin axis and exerted a direct control on sediment depositional processes. As structural depressions became buried, transverse input from point sources on the adjacent upper slope formed complex fan systems with sediment waves characterising the overbank environment, common on many Pleistocene turbidite systems. Mass failure as a result of local topographic inversion formed a prominent mass-flow deposit, and ultimately resulted in canyon formation and hence a new focused point source feeding the basin. The Valparaiso Basin is presently filled to the spill point of the outer forearc highs, causing headward erosion of incipient canyons into the basin fill and allowing bypass of sediment to the Chile Trench. Age estimates that are constrained by subduction-related syn-depositional deformation of the upper 700-800m of the basin fill suggest that glacio-eustatic sea-level lowstands, in conjunction with accelerated denudation rates, within the past 350 ka may have contributed to the increase in simultaneously active point sources along the upper slope as well as an increased

  11. Crustal Structure and Subsidence of the Williston Basin: Evidence from Receiver Function Stacking and Gravity Modeling

    Science.gov (United States)

    Song, J.; Liu, K. H.; Yu, Y.; Mickus, K. L.; Gao, S. S.

    2017-12-01

    The Williston Basin of the northcentral United States and southern Canada is a typical intracratonic sag basin, with nearly continuous subsidence from the Cambrian to the Jurassic. A number of contrasting models on the subsidence mechanism of this approximately circular basin have been proposed. While in principle 3D variations of crustal thickness, layering, and Poisson's ratio can provide essential constraints on the models, thick layers of Phanerozoic sediment with up to 4.5 km thickness prevented reliable determinations of those crustal properties using active or passive source seismic techniques. Specifically, the strong reverberations of teleseismic P-to-S converted waves (a.k.a. receiver functions or RFs) from the Moho and intracrustal interfaces in the loose sedimentary layer can severely contaminate the RFs. Here we use RFs recorded by about 200 USArray and other stations in the Williston Basin and adjacent areas to obtain spatial distributions of the crustal properties. We have found that virtually all of the RFs recorded by stations in the Basin contain strong reverberations, which are effectively removed using a recently developed deconvolution-based filter (Yu et al., 2015, DOI: 10.1002/2014JB011610). A "double Moho" structure is clearly imaged beneath the Basin. The top interface has a depth of about 40 km beneath the Basin, and shallows gradually toward the east from the depocenter. It joins with the Moho beneath the western margin of the Superior Craton, where the crust is about 30 km thick. The bottom interface has a depth of 55 km beneath the Wyoming Craton, and deepens to about 70 km beneath the depocenter. Based on preliminary results of H-k stacking and gravity modeling, we interpret the layer between the two interfaces as a high density, probably eclogized layer. Continuous eclogitization from the Cambrian to the Jurassic resulted in the previously observed rates of subsidence being nearly linear rather than exponential.

  12. Gondwana basins and their coal resources in Bangladesh

    International Nuclear Information System (INIS)

    Nehaluddin, M.; Sultan-ul-Islam, M.

    1994-01-01

    Fault bounded five Gondwana basins have been discovered in the north western Bangladesh. Among these basins show considerable amount of coal deposits. The Gondwana rocks are highly formed during the Permo-carboniferous diastrophism and later on acquired dynamic characters. In almost all basins, the Permian rocks overlie the Precambrian basement and underlie either the Tertiary or the Cretaceous sediments, structural, stratigraphic, and depositional history of these basins is more or less similar. The sedimentary sequences are composed of light to dark gray, fine to very coarse grained, sub angular to sub rounded felspathic sandstone, dark grey carbonaceous shale and sandstone, variegated conglomerate and thick coal seams (single seam max. 42.38m). The rocks are often alternated and bear the characteristics of cyclic sedimentation. The depositional environments varied from restricted drainage to open fluvial dominated low to moderate sinuous drainage system. The coal bearing basins were flanked by vegetated and swampy over bank. Age of these coals is suggested to be the late permian. Proved and probable reserves of coal in Jamalganj-Paharpur basin are 670 and 1,460 million metric tons, in Barapukuria basin 303 and 3899 million metric tons; in Barapukuria basin 303 and 389 million metric tons; and in Khalaspir basin 143 and 685 million metric tons respectively. The coal is high volatile, low sulphur, bituminous type. It can be used for different forms of thermal conversion. (author)

  13. Structural and Depositional Evolution of the Stevenson Basin, a Gulf of Alaska Forearc Basin: Insights from Legacy Seismic and Borehole Data

    Science.gov (United States)

    Bhattacharya, R.; Liberty, L. M.; Almeida, R. V.; Hubbard, J.

    2016-12-01

    We explore the structural and depositional evolution of the Stevenson Basin, Gulf of Alaska from a dense network of 2-D marine seismic profiles that span the Gulf of Alaska continental margin. The grid of 71 seismic profiles was acquired as part of a 1975 Mineral Management Services (MMS) exploration project to assess basin architecture along the Alaska continental shelf. We obtained unmigrated and stacked seismic profiles in TIFF format. We converted the data to SEGY format and migrated each profile. Within the Stevenson Basin, we identify key seismic horizons, including the regional Eocene-Miocene unconformity, that provide insights into its depositional and structural history. Using these observations combined with stacking velocities, sonic logs from wells, and refraction velocities from the Edge profile of Ye et al. (1997), we develop a local 3D velocity model that we use to depth-convert the seismic reflection profiles. By using ties to >2.5 km deep exploration wells, we note the Stevenson Basin is one of many Eocene and younger depocenters that span the forearc between Kodiak and Prince William Sound. Well logs and seismic data suggest basal strata consist of Eocene sediments than are unconformably overlain by Neogene and younger strata. Faults that breach the sea floor suggest active deformation within and at the bounds of this basin, including on new faults that do not follow any pre-existing structural trends. This assessment is consistent with slip models that place tsunamigenic faults that ruptured during the 1964 Great Alaska earthquake in the vicinity of the basin. The catalog of faults, their slip history and the depositional evolution of the Stevenson Basin, all suggest that the basin evolution may be controlled by heterogeneities along the incoming plate.

  14. The Jiuxi basin, Hexi Corridor, NW China: foreland structural features and hydrocarbon potential

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Q.M. (JAPEX Geoscience Inst. Inc., Tokyo (Japan)); Coward, M.P. (Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Geology)

    1993-04-01

    The Jiuxi (Western Jiuquan) Basin, located in the west of the Hexi Corridor, NW China, is a foreland basin which has been active since the Early Jurassic. It was formed as a consequence of the progressive northwards migration of the North Qilian thrusts in response to sinistral shearing along the 2,000-km long Aerjin (Altun) Fault. Sedimentary deposits in the basin are controlled not only by foreland loading and thrusting, but also by the development of listric normal faults at high angles to the thrust belt. At the junctions of these two sets of faults, thick organic-rich sediments and reservoirs have accumulated. During the Tertiary and Quaternary, thrusts propagated along the foot-wall of the North Qilian Fault, truncating earlier-formed oil pools and source-rock layers and thereby causing great difficulties for petroleum exploration. A basin development model is proposed in this paper from an integrated study of sedimentary facies, drilling and seismic data, structural analyses and cross-section reconstructions. The average northwards movement in the frontal zone of the North Qilian Mountains since the Pliocene is estimated at about 8 mm/yr. Therefore, about one-half of the Jurassic-Cretaceous oil-bearing basin could be buried beneath the Laojunmiao and North Qilian Marginal Faults and is virtually untouched by drilling. Source rocks in the basin are black, lacustrine shales of Late Jurassic through Early Cretaceous ages, with a maximum thickness of up to 1.2 km in the Qingxi Depression. The generation of liquid hydrocarbons began in the Late Cretaceous or mid-Oligocene: seven stratigraphical reservoirs, ranging in age from Silurian to Miocene, are described - anticlinal, fault- and ''buriedhill'' structures are the most important traps. The petroleum potential of individual depressions is discussed, and suggestions for potential regional oil prospects are made. (author)

  15. Characterization of basin concrete in support of structural integrity demonstration for extended storage

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, A. [Savannah River National Laboratory, Aiken, SC (United States)

    2014-09-30

    Concrete core samples from C basin were characterized through material testing and analysis to verify the design inputs for structural analysis of the L Basin and to evaluate the type and extent of changes in the material condition of the concrete under extended service for fuel storage. To avoid the impact on operations, core samples were not collected from L area, but rather, several concrete core samples were taken from the C Basin prior to its closure. C basin was selected due to its similar environmental exposure and service history compared to L Basin. The microstructure and chemical composition of the concrete exposed to the water was profiled from the water surface into the wall to evaluate the impact and extent of exposure. No significant leaching of concrete components was observed. Ingress of carbonation or deleterious species was determined to be insignificant. No evidence of alkali-silica reactions (ASR) was observed. Ettringite was observed to form throughout the structure (in air voids or pores); however, the sulfur content was measured to be consistent with the initial concrete that was used to construct the facility. Similar ettringite trends were observed in the interior segments of the core samples. The compressive strength of the concrete at the mid-wall of the basin was measured, and similar microstructural analysis was conducted on these materials post compression testing. The microstructure was determined to be similar to near-surface segments of the core samples. The average strength was 4148 psi, which is well-above the design strength of 2500 psi. The analyses showed that phase alterations and minor cracking in a microstructure did not affect the design specification for the concrete.

  16. Reexamination of the geological structure of the North German Basin in Lower Saxony

    Science.gov (United States)

    Rienäcker, Julia; Sattler, Sabine

    2016-04-01

    The North German Basin (NGB), as part of the Southern Permian Basin in Europe, extends from the North Sea, across Denmark, the Netherlands through Northern Germany, to Poland. It contains sediments from the Lower Permian to the Quaternary, and experienced a minimum subsidence of 2000 m from the Permian to the Mesozoic. This was followed by uplift during Late Cretaceous-Early Cenozoic inversion. The hundreds of meters thick and mobile Zechstein salt of Late Permian was remobilized in several phases to form complex salt structures. The salt moved laterally and vertically thus creating salt pillows and tall asymmetrical salt diapirs, some of which broke through the overburden until they were exposed at the paleo-surface. Salt structures influenced both the sedimentation and structural style throughout the NGB. Within the joint project TUNB (Deeper Underground North German Basin), 2-D/3-D seismic datasets, borehole data, structural maps and the existing 3-D geological model of Lower Saxony, will be used to create a new, detailed, geological 3-D model of the Lower Saxony part of the NGB. This allows new insights into the interplay between salt tectonics, sedimentation and tectonic movement, and in particular may help to resolve issues regarding the influence of the Zechstein salt on the sediment distribution. We show the different structural styles of important reservoir formations for, e.g., hydrocarbons, geothermal energy and gas storage, such as the Middle Buntsandstein, Rhaetkeuper, Middle Jurassic, and Lower Cretaceous, especially related to salt structures.

  17. Fracture Analysis of basement rock: A case example of the Eastern Part of the Peninsular Malaysia

    International Nuclear Information System (INIS)

    Shamsuddin, A; Ghosh, D

    2015-01-01

    In general, reservoir rocks can be defined into carbonates, tight elastics and basement rocks. Basement rocks came to be highlighted as their characteristics are quite complicated and remained as a significant challenge in exploration and production area. Motivation of this research is to solve the problem in some area in the Malay Basin which consist fractured basement reservoirs. Thus, in order to increase understanding about their characteristic, a study was conducted in the Eastern part of the Peninsular Malaysia. The study includes the main rock types that resemble the offshore rocks and analysis on the factors that give some effect on fracture characteristic that influence fracture systems and fracture networks. This study will allow better fracture prediction which will be beneficial for future hydrocarbon prediction in this region

  18. The role of internal waves in the formation of layered structure at exchange flows between two closed basins (Middle and southern basins of the Caspian sea

    Directory of Open Access Journals (Sweden)

    A. A. Bidokhti

    2005-12-01

    Full Text Available  Layered structures in the oceans have always attracted the attention of oceanographers. The formation of these structures have been attributed to phenomena such as double – diffusive convection, internal waves and turbulent modulated mixing .In this paper, the vertical structures of temperature, salinity, density and the layered structure in the middle parts of Caspian Sea have been studied. Counters of iso-quantities of these physical properties, show the existence of regular structures, which indicate that internal waves which are produced by exchanging flow between two basins, as a result of horizontal density gradients (usually from north basin to south basin may generate these layers. Froude number of this flow is about one. The length of wave of the internal waves is found to be about 200 km and the flow velocity associated with this gravity drive flow is about 0.2 m/s, the frequency of these waves is of order of inertial frequency. The normal modes of these waves have a near steady structure and can fold the inflow front from the North Caspian sea to South Caspian Sea basins, then the layered structure are formed. The thickness of these layers so formed is found to be about 10-20 m. These are in agreement with the values predicted by the model of Wong et al, (2001. In these waters density ratio is negative. Thus, double – diffusive convection does not often happen and cannot produce these layered structures.

  19. Geothermal prospection in the Greater Geneva Basin (Switzerland and France): Structural and reservoir quality assessment

    Science.gov (United States)

    Rusillon, Elme; Clerc, Nicolas; Makhloufi, Yasin; Brentini, Maud; Moscariello, Andrea

    2017-04-01

    A reservoir assessment was performed in the Greater Geneva Basin to evaluate the geothermal resources potential of low to medium enthalpy (Moscariello, 2016). For this purpose, a detail structural analysis of the basin was performed (Clerc et al., 2016) simultaneously with a reservoir appraisal study including petrophysical properties assessment in a consistent sedimentological and stratigraphical frame (Brentini et al., 2017). This multi-disciplinary study was organised in 4 steps: (1) investigation of the surrounding outcrops to understand the stratigraphy and lateral facies distribution of the sedimentary sequence from Permo-Carboniferous to Lower Cretaceous units; (2) development of 3D geological models derived from 2D seismic and well data focusing on the structural scheme of the basin to constrain better the tectonic influence on facies distribution and to assess potential hydraulic connectivity through faults between reservoir units ; (3) evaluation of the distribution, geometry, sedimentology and petrophysical properties of potential reservoir units from well data; (4) identification and selection of the most promising reservoir units for in-depth rock type characterization and 3D modeling. Petrophysical investigations revealed that the Kimmeridgian-Tithonian Reef Complex and the underlying Calcaires de Tabalcon units are the most promising geothermal reservoir targets (porosity range 10-20%; permeability to 1mD). Best reservoir properties are measured in patch reefs and high-energy peri-reefal depositional environments, which are surrounded by synchronous tight lagoonal deposits. Associated highly porous dolomitized intervals reported in the western part of the basin also provide enhanced reservoir quality. The distribution and geometry of best reservoir bodies is complex and constrained by (1) palaeotopography, which can be affected by synsedimentary fault activity during Mesozoic times, (2) sedimentary factors such as hydrodynamics, sea level variations

  20. Petroleum geology and resources of the West Siberian Basin, Russia

    Science.gov (United States)

    Ulmishek, Gregory F.

    2003-01-01

    The West Siberian basin is the largest petroleum basin in the world covering an area of about 2.2 million km2. The basin occupies a swampy plain between the Ural Mountains and the Yenisey River. On the north, the basin extends offshore into the southern Kara Sea. On the west, north, and east, the basin is surrounded by the Ural, Yenisey Ridge, and Turukhan-Igarka foldbelts that experienced major deformations during the Hercynian tectonic event and the Novaya Zemlya foldbelt that was deformed in early Cimmerian (Triassic) time. On the south, the folded Caledonian structures of the Central Kazakhstan and Altay-Sayan regions dip northward beneath the basin?s sedimentary cover. The basin is a relatively undeformed Mesozoic sag that overlies the Hercynian accreted terrane and the Early Triassic rift system. The basement is composed of foldbelts that were deformed in Late Carboniferous?Permian time during collision of the Siberian and Kazakhstan continents with the Russian craton. The basement also includes several microcontinental blocks with a relatively undeformed Paleozoic sedimentary sequence. The sedimentary succession of the basin is composed of Middle Triassic through Tertiary clastic rocks. The lower part of this succession is present only in the northern part of the basin; southward, progressively younger strata onlap the basement, so that in the southern areas the basement is overlain by Toarcian and younger rocks. The important stage in tectono-stratigraphic development of the basin was formation of a deep-water sea in Volgian?early Berriasian time. The sea covered more than one million km2 in the central basin area. Highly organic-rich siliceous shales of the Bazhenov Formation were deposited during this time in anoxic conditions on the sea bottom. Rocks of this formation have generated more than 80 percent of West Siberian oil reserves and probably a substantial part of its gas reserves. The deep-water basin was filled by prograding clastic clinoforms

  1. Population structure in the Mediterranean basin: a Y chromosome perspective.

    Science.gov (United States)

    Capelli, C; Redhead, N; Romano, V; Calì, F; Lefranc, G; Delague, V; Megarbane, A; Felice, A E; Pascali, V L; Neophytou, P I; Poulli, Z; Novelletto, A; Malaspina, P; Terrenato, L; Berebbi, A; Fellous, M; Thomas, M G; Goldstein, D B

    2006-03-01

    The Mediterranean region has been characterised by a number of pre-historical and historical demographic events whose legacy on the current genetic landscape is still a matter of debate. In order to investigate the degree of population structure across the Mediterranean, we have investigated Y chromosome variation in a large dataset of Mediterranean populations, 11 of which are first described here. Our analyses identify four main clusters in the Mediterranean that can be labelled as North Africa, Arab, Central-East and West Mediterranean. In particular, Near Eastern samples tend to separate according to the presence of Arab Y chromosome lineages, suggesting that the Arab expansion played a major role in shaping the current genetic structuring within the Fertile Crescent.

  2. Tectonic and Structural Controls of Geothermal Activity in the Great Basin Region, Western USA

    Science.gov (United States)

    Faulds, J. E.; Hinz, N.; Kreemer, C. W.

    2012-12-01

    We are conducting a thorough inventory of structural settings of geothermal systems (>400 total) in the extensional to transtensional Great Basin region of the western USA. Most of the geothermal systems in this region are not related to upper crustal magmatism and thus regional tectonic and local structural controls are the most critical factors controlling the locations of the geothermal activity. A system of NW-striking dextral faults known as the Walker Lane accommodates ~20% of the North American-Pacific plate motion in the western Great Basin and is intimately linked to N- to NNE-striking normal fault systems throughout the region. Overall, geothermal systems are concentrated in areas with the highest strain rates within or proximal to the eastern and western margins of the Great Basin, with the high temperature systems clustering in transtensional areas of highest strain rate in the northwestern Great Basin. Enhanced extension in the northwestern Great Basin probably results from the northwestward termination of the Walker Lane and the concomitant transfer of dextral shear into west-northwest directed extension, thus producing a broad transtensional region. The capacity of geothermal power plants also correlates with strain rates, with the largest (hundreds of megawatts) along the Walker Lane or San Andreas fault system, where strain rates range from 10-100 nanostrain/yr to 1,000 nanostrain/yr, respectively. Lesser systems (tens of megawatts) reside in the Basin and Range (outside the Walker Lane), where local strain rates are typically fracture density, and thus enhanced permeability. Other common settings include a) intersections between normal faults and strike-slip or oblique-slip faults (27%), where multiple minor faults connect major structures and fluids can flow readily through highly fractured, dilational quadrants, and b) normal fault terminations or tip-lines (22%), where horse-tailing generates closely-spaced faults and increased permeability

  3. Preliminary integration study of Precambrian with tectonic events in Brazilian sedimentary basins (Republication); Estudo preliminar de integracao do Pre-Cambriano com os eventos tectonicos das bacias sedimentares brasileiras (Republicacao)

    Energy Technology Data Exchange (ETDEWEB)

    Cordani, Umberto G.; Neves, Benjamim B. Brito; Fuck, Reinhard A.; Porto, Roberto; Thomaz Filho, Antonio; Cunha, Francisco M. Bezerra da

    2008-11-15

    The various successive episodes of vertical cratogenic evolution modelling the geo tectonic features of the basement were correlated with the internal structure, shape, origin and geologic evolution of the sedimentary basin. A systematic petrologic and geochronological investigation of all available drill core samples was carried out, and the pertinent geophysical data regarding basement structure were taken into consideration. Specific geo tectonic analyses, were carried out along the borders of the sedimentary basins, within the adjacent basement. The main boundaries between Precambrian tectonic provinces, the main tectonic sutures with polycyclic evolution, and the ancient intracratonic rifts were identified wherever possible. Their extensions under the sedimentary basins were inferred, corroboration being sought from structural information and data obtained from the drill core samples. It was found that many of the identified basement discontinuities had a direct influence on the depositional history of each of the sedimentary basins, demonstrating the distinct tectonic inheritance. The subject was treated on a reconnaissance scale, 1:1.000.000 or smaller,owing to its complexity. (author)

  4. A Nonlinear Inversion Approach to Map the Magnetic Basement: A Case Study from Central India Using Aeromagnetic Data

    Science.gov (United States)

    Kumar, R.; Bansal, A. R.; Anand, S. P.; Rao, V. K.; Singh, U. K.

    2016-12-01

    The central India region is having complex geology covering various geological units e.g., Precambrian Bastar Craton (including Proterozoic Chhattisgarh Basin, granitic intrusions etc.) and Eastern Ghat Mobile Belt, Gondwana Godavari and Mahanadi Grabens, Late Cretaceous Deccan Traps etc. The central India is well covered by reconnaissance scale aeromagnetic data. We analyzed this data for mapping the basement by dividing into143 overlapping blocks of 100×100km using least square nonlinear inversion method for fractal distribution of sources. The scaling exponents and depth values are optimized using grid search method. We interpreted estimated depths of anomalous sources as magnetic basement and shallow anomalous magnetic sources. The shallow magnetic anomalies are found to vary from 1 to 3km whereas magnetic basement depths are found to vary from 2km to 7km. The shallowest basement depth of 2km found corresponding to Kanker granites a part of Bastar Craton whereas deepest basement depth of 7km is associated with Godavari Graben and south eastern part of Eastern Ghat Mobile Belts near the Parvatipuram Bobbili fault. The variation of magnetic basement, shallow depths and scaling exponent in the region indicate complex tectonic, heterogeneity and intrusive bodies at different depths which is due to different tectonic processes in the region. The detailed basement depth of central India is presented in this study.

  5. Lacustrine fan delta deposition alongside intrabasinal structural highs in rift basins: an example from the Early Cretaceous Jiuquan Basin, Northwestern China

    Science.gov (United States)

    Zhang, Chengcheng; Muirhead, James D.; Wang, Hua; Chen, Si; Liao, Yuantao; Lu, Zongsheng; Wei, Jun

    2018-01-01

    Development of fan deltas alongside intrabasinal structural highs has been overlooked compared to those forming on basin margins. However, these fan deltas may provide important clues regarding the tectonic and climatic controls on deposition during rift development. This paper documents fan delta deposition alongside an intrabasinal structural high within the Early Cretaceous Xiagou Formation of the Jiuquan Basin, China, using subsurface geological and geophysical data. Deposits observed in drill core support fan delta deposition occurring almost exclusively through subaerial and subaqueous gravity flows. Subsurface mapping reveals a consistent decrease in the areal extent of fan deltas from lowstand to highstand system tracts, suggesting that deposition alongside the structural high is sensitive to lake-level changes. The temporal and spatial distribution of the fan deltas display retrogradational stacking patterns, where fan deltas exhibit a decreasing lateral extent up-sequence until fan delta deposition terminated and was replaced by deposition of fine-grained lacustrine deposits. The retrogradational stacking patterns observed alongside the intrabasinal structural high are not observed in fan deltas along the basin margin in the lower parts of the Xiagou Formation. Subsidence profiles also show differential subsidence across the basin during the earliest stages of this formation, likely resulting from border fault movements. These data suggest that non-uniform stacking patterns in the lower parts of the Xiagou Formation reflect basin-scale tectonic movements as the dominant control on synrift deposition patterns. However, later stages of Xiagou Formation deposition were characterized by uniform subsidence across the basin, and uniform retrogradational stacking patterns for fan deltas alongside the intrabasinal structural high and border fault. These observations suggest that basin-scale tectonic movements played a relatively limited role in controlling

  6. Basement configuration of KG offshore basin from magnetic anomalies

    Indian Academy of Sciences (India)

    2Department of Geology, Adikavi Nannaya University, GSL SO, Rajahmundry 533 296, India. ∗. Corresponding author. e-mail: baalukandadai@yahoo.co.in. Marine magnetic ..... Sri Lanka, India and Antarctica; Osaka City University;. J. Geosci. 31 1–17. MS received 11 May 2015; revised 30 November 2015; accepted 6 ...

  7. Paleogene strata of the Eastern Los Angeles basin, California: Paleogeography and constraints on neogene structural evolution

    Science.gov (United States)

    McCulloh, T.H.; Beyer, L.A.; Enrico, R.J.

    2000-01-01

    Post-Paleogene dextral slip of 8-9 km is demonstrated for the southeastern part of the Whittier fault zone in the eastern Los Angeles basin area of southern California. A linear axis of greatest thickness for the combined upper Paleocene and lower to lower-middle Eocene clastic formations intersects the fault zone and is offset by it to give the new measure. Fragmentary evidence hints that the Whittier structural zone may have exerted control on bathymetric-topographic relief and sedimentation even in latest Paleocene (ca. 54 Ma). A clear topographic influence was exerted by 20-17 Ma. Strike-slip and present deformational style is younger than ca. 8 Ma. Our Paleogene isopach map extends as far west as long 117??58'W and is a foundation for companion zonal maps of predominant lithology and depositional environments. Integration of new palynological data with published biostratigraphic results and both new and published lithologic and sedimentological interpretations support the zonal maps. Reconstruction of marine-nonmarine facies and fragmented basin margins yields a model for the northeastern corner of a Paleogene coastal basin. Palinspastic adjustment for the Neogene-Quaternary Whittier fault offset and a reasoned westerly extension of the northern edge of the basin model yield a reconstruction of Paleogene paleogeography-paleoceanography. Our reconstruction is based partly on the absence of both Paleocene and Eocene deposits beneath the unconformable base of the middle Miocene Topanga Group in a region nowhere less than 15 km wide between the Raymond-Sierra Madre-Cucamonga fault zone and the northern edge of the Paleocene basin. Thus, Paleogene strata of the Santa Monica Mountains could not have been offset from the northern extension of the Santa Ana Mountains by sinistral slip on those boundary faults. Structural rearrangements needed to accommodate the clockwise rotation of the western Transverse Ranges from the early Miocene starting position are thereby

  8. Analysis of Basin-Range Coupling Mechanisms during Epeirogenetic Uplift - A Case Study of Tectonic Coupling in the Songpan-Ganzi Plateau-Longmen Mountain-Sichuan Basin Region

    Science.gov (United States)

    Ying, Danlin; Li, Ying

    2017-04-01

    The tectonodynamic evolution of the Songpan-Ganzi Plateau-Longmen Mountain-Sichuan basin region has been analyzed in this paper. The result suggested that the region had experienced principal four stages of evolution. The evolution was beginning with crystalline basement and folded basement formation in the pre-Sinian, then the cartonmarine sedimentary basin from the Sinian to the Middle Triassic was followed by uplift and stretching of the land from the Late Triassic to the Middle Jurassic, and finally compressive orogenesis since the Late Jurassic was happened. To understand the uplift and stretching of the land from the Late Triassic to the Middle Jurassic, a physical modeling experiment was conducted. It was confirmed that a tectonic plateau-ramp-basin geomorphology pattern developed during this period, caused by the wide difference in uplift between the Songpan-Ganzi Plateau and the Sichuan Basin. In the plateau region, the tectonic dynamic environment of uplift and stretching of the land (trailing edge extension) had appeared, which was accompany with the extensional structure styles such as normal faults and graben-horst structures. On the slope between the plateau and the basin, a bedding shear geodynamic environment was formed, and compressive slumped overthrust structure was found for the sliddown of decollement layers under the force of gravity. In the basin, compressive tectonic dynamic environment had emerged, which leaded to a compressive structure, such as thrust faults, overturned folds, and fault-related folds.

  9. The ordered network structure and its prediction for the big floods of the Changjiang River Basins

    International Nuclear Information System (INIS)

    Men, Ke-Pei; Zhao, Kai; Zhu, Shu-Dan

    2013-01-01

    According to the latest statistical data of hydrology, a total of 21 floods took place over the Changjiang (Yangtze) River Basins from 1827 to 2012 and showed an obvious commensurable orderliness. In the guidance of the information forecasting theory of Wen-Bo Weng, based on previous research results, combining ordered analysis with complex network technology, we focus on the summary of the ordered network structure of the Changjiang floods, supplement new information, further optimize networks, construct the 2D- and 3D-ordered network structure and make prediction research. Predictions show that the future big deluges will probably occur over the Changjiang River Basin around 2013-2014, 2020-2021, 2030, 2036, 2051, and 2058. (orig.)

  10. Architecture and tectono-stratigraphic evolution of the intramontane Baza Basin (Bétics, SE-Spain): Constraints from seismic imaging

    Science.gov (United States)

    Haberland, Christian; Gibert, Luis; Jurado, María José; Stiller, Manfred; Baumann-Wilke, Maria; Scott, Gary; Mertz, Dieter F.

    2017-07-01

    The Baza basin is a large Neogene intramontane basin in the Bétic Cordillera of southern Spain that formed during the Tortonian (late Miocene). The Bétic Cordillera was produced by NW-SE oblique convergence between the Eurasian and African Plates. Three seismic reflection lines (each 18 km long; vibroseis method) were acquired across the Baza basin to reveal the architecture of the sedimentary infill and faulting during basin formation. We applied rather conventional CDP data processing followed by first arrival P-wave tomography to provide complementary structural information and establish velocity models for the post-stack migration. These images show a highly asymmetric structure for the Basin with sediments thickening westward, reaching a maximum observed thickness of > 2200 m near the governing Baza Fault zone (BFZ). Three major seismic units (including several subunits) on top of the acoustic basement could be identified. We use stratigraphic information from the uplifted block of the BFZ and other outcrops at the basin edges together with available information from neighboring Bétic basins to tentatively correlate the seismic units to the known stratigraphy in the area. Until new drilling or surface outcrop data is not available, this interpretation is preliminary. The seismic units could be associated to Tortonian marine deposits, and latest Miocene to Pleistocene continental fluvio-lacustrine sediments. Individual strands of the BFZ truncate the basin sediments. Strong fault reflections imaged in two lines are the product of the large impedance contrast between sedimentary fill and basement. In the central part of the Basin several basement faults document strong deformation related to the early stages of basin formation. Some of these faults can be traced up to the shallowest imaged depth levels indicating activity until recent times.

  11. Collective cell behavior on basement membranes floating in space

    Science.gov (United States)

    Ellison, Sarah; Bhattacharjee, Tapomoy; Morley, Cameron; Sawyer, W.; Angelini, Thomas

    The basement membrane is an essential part of the polarity of endothelial and epithelial tissues. In tissue culture and organ-on-chip devices, monolayer polarity can be established by coating flat surfaces with extracellular matrix proteins and tuning the trans-substrate permeability. In epithelial 3D culture, spheroids spontaneously establish inside-out polarity, morphing into hollow shell-like structures called acini, generating their own basement membrane on the inner radius of the shell. However, 3D culture approaches generally lack the high degree of control provided by the 2D culture plate or organ-on-chip devices, making it difficult to create more faithful in vitro tissue models with complex surface curvature and morphology. Here we present a method for 3D printing complex basement membranes covered in cells. We 3D print collagen-I and Matrigel into a 3D growth medium made from jammed microgels. This soft, yielding material allows extracellular matrix to be formed as complex surfaces and shapes, floating in space. We then distribute MCF10A epithelial cells across the polymerized surface. We envision employing this strategy to study 3D collective cell behavior in numerous model tissue layers, beyond this simple epithelial model.

  12. A reassessment of the Archean-Mesoproterozoic tectonic development of the southeastern Chhattisgarh Basin, Central India through detailed aeromagnetic analysis

    Science.gov (United States)

    Sridhar, M.; Ramesh Babu, V.; Markandeyulu, A.; Raju, B. V. S. N.; Chaturvedi, A. K.; Roy, M. K.

    2017-08-01

    We constrained the geological framework over polydeformed Paleoproterozoic Sonakhan Greenstone Belt and addressed the tectonic evolution of Singhora basin in the fringes of Bastar Craton, central India by utilizing aeromagnetic data interpretation, 2.5D forward modelling and 3D magnetic susceptibility inversions. The Sonakhan Greenstone Belt exposes volcano-sedimentary sequences of the Sonakhan Group within NNW-SSE to NW-SE trending linear belts surrounded by granite gneisses, which are unconformably overlain by sedimentary rocks of Chhattisgarh Basin. The orientations of aeromagnetic anomalies are coincident with geological trends and appear to correlate with lithology and geologic structure. Regional magnetic anomalies and lineaments reveal both NNW-SSE and NE-SW trends. Prominent E-W trending linear, high amplitude magnetic anomalies are interpreted as the Trans-Chhattisgarh Aeromagnetic Lineament (TCAL). NW-SE trending aeromagnetic signatures related to Sonakhan Greenstone Belt extends below the Singhora sedimentary rocks and forms the basement in the west. The analysis suggests that TCAL is a block fault with northern block down-thrown and affected the basement rocks comprising the Sonakhan Greenstone Belt and Samblapur Granitoids. The episode of faulting represented by the TCAL is pre-Singhora sedimentation and played a vital role in basin evolution. The basement configuration image generated by estimates of depth to magnetic basement suggests a complex pattern of NNE-SSW to NE-SW trending depressions separated by a linear N-S trending basement ridge. It is inferred from the 3D magnetic susceptibility inversion that the thickness of sediments is more towards the eastern basin margin and the N-S ridge is a manifestation of post sedimentary faulting. Results of 2.5D modelling of a WNW-ESE profile across the Singhora Basin combined with results from 3D inversion suggest suggests the basin subsidence was controlled by NE-SW trending regional faults in an active

  13. Insights on the evolution of mid-ocean basins: the Atlantis Basin of southern Azores

    Science.gov (United States)

    Alves, T.; Bouriak, S.; Volkonskaya, A.; Monteiro, J.; Ivanov, M.

    2003-04-01

    Single-channel seismic reflection and sidescan (OKEAN) data acquired in an unstudied region of the North Atlantic give important insights on the evolution of mid-ocean basins. Located on the eastern flank of the Mid-Atlantic Ridge, south of the Azores Islands, the study area contains more than 1,000 ms two-way travel-time of sediments with a similar seismic stratigraphy to that of ODP sites 950-952 in the Madeira Abyssal Plain. Processed thickness values correspond to a maximum thickness of about 1450 m and an average thickness of more than 500 m based on velocity data from ODP sites 950-952. The structure of the surveyed area and its location in relation to the Madeira Abyssal Plain and Mid-Atlantic Ridge indicate the existence, south of Azores, of two distinct sedimentary basins separated by major structural lineaments (Azores-Gibraltar and Atlantis Fracture Zones) and by seamount chains (Cruiser-Great Meteor Chain, Plato-Atlantis Chain). The basement of the sedimentary basins is irregular, showing multiple dome-shaped volcanic structures identical to those in the Norwegian-Greenland Sea and Madeira Abyssal Plain. However, half-graben/graben basement blocks predominate east of 30ºW underneath a moderately deformed overburden. The complex structure observed most likely reflects changes in the direction and velocity of ocean spreading plus variations in the regional thermal gradients induced by local hot spots. In parallel, some of the sub-surface structures identified next to basin-bounding Fracture Zones may have resulted from transtensional and transpressional tectonism.

  14. The Hatton Basin and continental margin: Crustal structure from wide-angle seismic and gravity data

    Science.gov (United States)

    Vogt, Ulrike; Makris, Jannis; O'Reilly, Brian M.; Hauser, Franz; Readman, Peter W.; Jacob, A. W. Brian; Shannon, Pat M.

    1998-06-01

    Results from a wide-angle seismic and gravity study between the Rockall Bank and the Iceland Basin in the North Atlantic are presented. Crustal and sedimentary structures are resolved in the Hatton Basin and across the Hatton continental margin (HCM) east of magnetic anomaly 24. The structure of the oceanic crust west of the anomaly is also determined. Gravity data support the seismic model in areas of good seismic coverage and are used to control the model where the wide-angle seismic data are poor. A two-layer sedimentary sequence is present both in the Hatton Basin and across the continental margin. The lower layer, with P wave velocity of about 4 km/s, is interpreted as pre-Eocene synrift sediments and is up to 3.5 km thick. A younger and thinner (1-2.5 km) postrift sequence, with a velocity of about 2 km/s, defines a strong velocity contrast, which suggests an erosional unconformity surface. The sedimentary structure is distinctly different from that in the Rockall Trough, where a third intermediate layer (Vp ≈ 3 km/s) occurs. The three-layer crust, characterized by two intracrustal reflections (PiP1 and PiP2) varies from 30 km thick under the Rockall Bank to about 15 km below the Hatton Basin, where it is stretched by a factor of 2 relative to onshore Ireland. The crust is thinnest below the Hatton Bank, where the presence of a single intracrustal reflection indicates that the lower crustal layer thins to below the seismic resolution limit. Below the HCM a region of thick lower crust with anomalously high velocity (Vp ≈ 7.2 km/s) is resolved by the seismic and gravity data. It is connected (west of anomaly 24) to a region of oceanic crust, which is thicker than in the Iceland Basin. These relationships between the thick lower crust below the HCM and the oceanic crust in the Iceland Basin are interpreted as evidence for magmatic underplating, consistent with previous models for the HCM. The inferred unconformity surface between the synrift and postrift

  15. The Brazilian marginal basins: current state of knowledge; As bacias marginais brasileiras: estagio atual de conhecimento

    Energy Technology Data Exchange (ETDEWEB)

    Ponte, Francisco Celso; Asmus, Haroldo Erwin

    2004-11-01

    Based on distinctive stratigraphic and/or structural characteristics, the brazilian continental margin can be divided into two main provinces : (1)The southeastern-eastern province, extending from the Pelotas to the Recife - Joao Pessoa Basin, presents a tensional tectonic style of Late Jurassic - Early Cretaceous age, paralleling the structural alignments of the Precambrian basement, except in the northeastern segment where the Mesozoic faults of the Recife - Joao Pessoa Basin cut across the east west basement directions. The basin-fill, Upper Jurassic through Recent, consists, where complete, of three stratigraphic sequences, each of a distinct depositional environment: (a) a lower clastic non-marine sequence; (b) a middle evaporitic sequence, and (c) an upper clastic paralic and open marine sequence. (2)The northern province, extending from the Potiguar Basin to the Amazon Submarine Basin, displays both tensional and compressional tectonic styles of Upper Jurassic (?) to Upper Cretaceous age either paralleling or cutting transversally the basement alignments. The stratigraphic column differs from the southeastern - eastern province in lacking the Lower Cretaceous evaporitic rocks. The integration of the stratigraphic and structural data allows one to determine in the eastern Brazilian marginal basins the main evolutionary stages of a typical pull-apart continental margin: a continental pre-rift and rift stage, an evaporitic proto-ocean stage, and a normal open ocean stage. In the northern province it is possible to infer a continental rift valley stage, a marine transform - movement stage and an open ocean stage. The relationship between the rift valley and transform movement stages is not clear. (author)

  16. Contribution To The Geology Of Basement Rocks In The South Western Desert Of Egypt

    International Nuclear Information System (INIS)

    Sadek, M.F.; Khyamy, A.A.

    2003-01-01

    Three major Precambrian basement inliers are exposed in the South Western Desert of Egypt between Long. 29 degree E and the River Nile within the Uweinat-Bir Safsaf-Aswan E-W uplift system. These are Bir Safsaf, Gabal EI-Asr and Gabal Umm Shaghir areas. Smaller outcrops include Gabal EI-Gara El-Hamra and Gabal El-Gara EI-Soda, Gabal Siri, GabaI EI-Fantas and Aswan-Kalabsha area as well as the scattered outcrops around Darb El-Arbain road. Band ratios 5/7, 5/1, 4 of Landsat TM images were applied to delineate the borders, the lithologic units and structural features of low relief basement outcrops within the surrounding flat lying sedimentary rocks and sand plains. These basement rocks comprise ortho gneisses (assumed by many authors as related to old continent pre Pan-African rocks), G 1 tonalite-granodiorite, and G2 monzogranite-alkali feldspar granite intruded by variable dykes. The boundaries between the basement exposures and the sedimentary rocks are marked by nonconformity surfaces or sets of faults. Both basement and sedimentary rocks are intruded by Mesozoic syenite-G3 granites, rhyolite, trachytic plugs and Upper Cretaceous to Tertiary basalts. The basement exposures are structurally controlled by major E- W fault systems. Their vertical uplifting is overprinted by folding the overlying sedimentary rocks. This study revealed that, the different basement exposures in the SE of the Western Desert of Egypt are similar in appearance and field relations to the Pan-African basement rocks extending towards the east of the River Nile and exposed everywhere in the Eastern Desert of Egypt

  17. SHRIMP chronology of the Magallanes Basin basement, Tierra del Fuego: Cambrian plutonism and Permian high-grade metamorphism Geocronología SHRIMP del basamento de la Cuenca de Magallanes, Tierra del Fuego: plutonismo Cámbrico y metamorfismo Pérmico de alto grado

    Directory of Open Access Journals (Sweden)

    Francisco Hervé

    2010-07-01

    Full Text Available Five new SHRTMP U-Pb zircon ages are reported for gneisses and foliated plutonic rocks belonging to the Tierra del Fuego igneous and metamorphic basement complex (TFIMC, obtained from the bottom of borehole cores through the Magallanes Basin. Three of the samples yielded weighted mean 206Pb/238U ages (523±7 Ma, 522±6 Ma and 538±6 Ma, interpreted as indicating Early Cambrian igneous crystallization of the host rocks. A migmatitic gneiss shows peaks at ca. 950-1,100 Ma and 560-650 Ma from inherited zircon grains in addition to two grains with ages of ca. 525 Ma, suggesting involvement of Grenvillian and Brasiliano material in the protolith of a Cambrian migmatite. A cordierite-sillimanite-garnet gneiss contains igneous zircons of Cambrian age and a population of U-rich metamorphic Permian zircons, indicating that a Permian high-grade metamorphic and anatectic (P=2-3 kbar, T=730-770°C event affected the Cambrian igneous rocks or sedimentary rocks derived from them. Cambrian/Ediacaran plutonic rocks are known from the basement of NW Argentina, the Sierra de la Ventana, the Cape Fold Belt in South Africa, and the Ross Orogen in Antarctica. The Permian metamorphic event is coeval with the deformation and low-grade metamorphism of the sedimentary successions that overlie the basement in many of these areas. In Tierra del Fuego at least 8 to 12 km of cover rocks were removed following the high-grade Permian metamorphic episode and the unconformable deposition of the Tobífera Formation volcanic rocks in the Middle to Late Jurassic. This eroded cover could nave been an important source of detritus for the conglomeratic Permian and Triassic? Successions of neighboring regions in South America, Africa and Antarctica.Cinco nuevas edades radiométricas logradas mediante análisis U-Pb en circón utilizando el SHRIMP, fueron determinadas en gneises y rocas plutónicas foliadas obtenidas desde el fondo de pozos de sondajes en la Cuenca de Magallanes y

  18. Numerical Modeling of Regional Groundwater Flow in a Structurally Complex Intermountain Basin: South Park, Colorado

    Science.gov (United States)

    Ball, L. B.; Caine, J. S.; Ge, S.

    2012-12-01

    A steady-state, 3-D groundwater flow model of the South Park basin was developed to explore the influence of realistically complex topography and permeability structure on the patterns of basin-wide groundwater flow and to evaluate the sensitivity of the groundwater flow system to increased variability in recharge distribution and the influence of hydrogeologically distinct fault zones. South Park is a large, semi-arid intermountain basin (3300 km2) flanked by crystalline rocks and floored with faulted and folded sedimentary rocks and volcanic deposits. Model results suggest that, while the majority (>80%) of water entering the groundwater flow system is discharged through seepage faces in steep terrain or routed to mountain streams, internal exchanges of groundwater and stream flow between the mountain and valley landscapes are an important part of the dynamics of groundwater flow in the basin. The majority of topographically driven groundwater flow is focused in the upper 300 m of the model domain and would be considered local to intermediate in "Tothian" scales. Less than 1% of groundwater flow passes below 1 km in depth, and large-scale regional circulation is a limited component of the groundwater flow system. Increasingly heterogeneous recharge distributions most heavily impacted the groundwater flow system at the local scale, while basin-wide regional flow remained relatively insensitive to the increasing variability in recharge distribution. The introduction of end-member conduit and barrier types of fault zones influenced hydraulic heads and gradients within 5-10 km of the fault location where groundwater flow directions are perpendicular to the orientation of the fault. Where groundwater flow directions are oblique or subparallel to the fault, the introduction of distinct fault zones had a negligible impact on hydraulic heads or gradients.

  19. A Gravity Analysis of the Subsurface Structure of the Utopia Impact Basin

    Science.gov (United States)

    Barnerdt, W. B.

    2004-01-01

    The large, shallow, circular depression in Utopia Planitia has been identified as a huge impact basin, based on both geological evidence and detailed analysis of MOLA topography. Its diameter (approximately 3000 km) is equivalent to that of the Hellas basin, as is its inferred age (early Noachian). However, there the similarity ends. Their appearance, both surficially and geophysically, are virtually polar opposites. Whereas Hellas is extremely deep with rough terrain and large slopes, high-precision MOLA measurements were required to unambiguously define the smooth, shallow, almost imperceptible bowl of the Utopia basin. Conversely, Utopia displays one of the largest (non-Tharsis-related) positive geoid anomalies on Mars, in contrast to a more subdued negative anomaly over Hellas. As these two features presumably formed roughly contemporaneously by similar mechanisms, it is reasonable to assume that they were originally quite similar, and that their differences are due largely to different paths of subsequent modification. The obvious source for these differences is in their elevations: Hellas is located in the southern highlands at a rim elevation of about 3km, whereas Utopia is in the lowlying northern plains, at an average elevation of 4 km. Thus Utopia has been in an especially gravitationally favorable position to be subjected to infilling, for example, by lava flows, sedimentation, or water. In fact, its floor was almost certainly the lowest point on the planet at one time, and it would have been the termination point for down-slope drainage from over two-thirds of Mars. Thus the nature of the material filling this basin has strong connections to the sedimentary and/or volcanic processes acting on Mars in the Noachian and Early Hesperian periods. In particular, it may be able to shed some light on amount and persistence of water on early Mars in general and in the Utopia basin in particular. In this study I will use the inferred early correspondence between

  20. Late Cretaceous and Cenozoic seafloor and oceanic basement roughness: Spreading rate, crustal age and sediment thickness correlations

    Science.gov (United States)

    Bird, Robert T.; Pockalny, Robert A.

    1994-05-01

    Single-channel seismic data from the South Australian Basin and Argentine Basin, and bathymetry data from the flanks of the Mid-Atlantic Ridge, East Pacific Rise and Southwest Indian Ridge are analysed to determine the root-mean-square (RMS) roughness of the seafloor and oceanic basement created at seafloor spreading rates ranging from 3 to 80 km/Ma (half-rate). For these data, crustal ages range from near zero to 85 Ma and sediment thicknesses range from near zero to over 2 km. Our results are consistent with a negative correlation of basement roughness and spreading rate where roughness decreases dramatically through the slow-spreading regime (oceanic basement roughness and spreading rate appears to have existed since the late Cretaceous for slow and intermediate spreading rates, suggesting that the fundamental processes creating abyssal hill topography may have remained the same for this time period. Basement roughness does not appear to decrease (smooth) with increasing crustal age, and therefore off-ridge degradation of abyssal hill topography by mass wasting is not detected by our data. Seismic data reveal that sediment thickness increases with increasing crustal age in the South Australian Basin and Argentine Basin, but not monotonically and with significant regional variation. We show that minor accumulations of sediment can affect roughness significantly. Average sediment accumulations of less that 50 m (for our 100 km long sample seismic profiles and half-spreading rates ocean ridges.

  1. A double-layer structure model of uranium-bearing horizon in inland basins of medium to big size, North-west China, and its significance in metallogenic potential assessment

    International Nuclear Information System (INIS)

    Wang Zhilong.

    1985-01-01

    This paper presents a double-layer structure model of uranium-bearing horizon, i.e. uranium-bearing horizon = source rock (arkose red beds) + uranium trap (grey beds favourable to uranium precipitation) in inland basins of medium to big size, North-west China. The mechanism of its formation is: during diagenetic-epigenetic processes resulted in arkose red bed formation, feldspar was hydromicatized, feldspar and quartz were replaced by authigenic hematite, goethite and hydrogoethite and became red. In such oxidation process, part of uranium in detritus of silicates such as feldspar, quartz etc. was mobilized and released, but the released uranium can not be precipitated because of the oxidation environment, and it can be diffused during diagenetic dehydration and then precipitated in nearby grey beds with low Eh together with uranium-bearing 'stagnant water' fixed in pores, forming economic uranium concentration. It is evident that uranium deposit could not be formed owing to uranium dispersion in the case of absence of certain pervious grey beds rich in reductants, although arkose red beds could provide sufficient uranium source. Therefore, only the two conditions existed simultaneously, could the uranium-bearing horizons be formed. The significance of the model for uranium prospecting are as follows: 1. Uranium source range is much expanded concerning uranium prospecting in sandstone. Except the source in basement of the basin and its margins, we must also pay attention to the overlying red beds, especially the arkose red beds in inland basin of medium to big size. 2. For the potential assessment of basin and the selection of potential area, the model is an important prospecting criterion. 3. If we apply the main criterion uranium-bearing horizon-arkose red beds well, the buried ore bodies can be found provided that arkose red beds were regarded as a significant criterion of uranium-bearing horizon

  2. New seismo-stratigraphic data of the Volturno Basin (northern Campania, Tyrrhenian margin, southern Italy: implications for tectono-stratigraphy of the Campania and Latium sedimentary basins

    Directory of Open Access Journals (Sweden)

    Ennio Marsella

    2011-07-01

    Full Text Available A geological section of the Volturno Basin (northern Campania, continental margin, Italy has been constructed based on new multi-channel seismic data, to show the stratigraphic relationships between the filling in the Quaternary basin and the Meso-Cenozoic acoustic basement. The new seismic sections presented here outline the underlying structures of the basin and their relationships to the filling in the Quaternary basin. Deep exploration wells in Campania and Latium on the Tyrrhenian margin have gathered litho-stratigraphic and commercial multi-channel seismic data that can be used for better integration of the geological data for the area under study. The trending of the seismic units is controlled by the Massico Structural High, which forms the boundary of the Volturno Basin towards the north-west. This produces a geometry that is characteristic of a fan complex, with NE-SW trending. This qualitative calibration of the seismic sequences that fill the sedimentary basin was carried out through the litho-stratigraphic data of the «Castelvolturno 2» well, which highlights the pyroclastic layers and conglomeratic strata of the lagoon and delta environments as they evolve upwards towards marine sediments. Seismo-stratigraphic analysis shows the complex depositional geometries of the filling in the Volturno Basin, which overlie the Meso-Cenozoic carbonatic basement and the related flysch deposits. Coupled with regional geological evidence, the data interpretation here suggests that the Volturno Basin represents a half-graben structure that is characterized by down-thrown blocks along normal faults.

  3. Meso–Cenozoic lithospheric thermal structure in the Bohai Bay Basin, eastern North China Craton

    Directory of Open Access Journals (Sweden)

    Zongxing Li

    2017-09-01

    Full Text Available The Bohai Bay Basin is a region where part of the North China Craton has been thinned and destroyed. It has experienced two periods of crustal thinning that occurred during the Cretaceous and Paleogene, but investigations of its Mesozoic and Cenozoic lithospheric thermal structure are limited. Therefore, in this study, the distributions of mantle heat flow, crustal heat flow, and Moho temperatures during the Meso–Cenozoic are calculated based on analyses of the thermal history of the Bohai Bay Basin. The results indicate that the ratio of mantle heat flow to surface heat flow peaked during the late stages of the early Cretaceous and during the middle to late Paleogene. The corresponding mantle heat flow was more than 65% of the surface heat flow. Moho temperatures reached three peaks: 900–1100 °C in the late stages of the early Cretaceous; 820–900 °C in the middle to late Paleogene; and (in the Linqing Depression, Cangxian Uplift, and Jizhong Depression 770–810 °C during the early Neogene. These results reveal that the Bohai Bay Basin experienced significant geological change during the Cretaceous, including the transformation of lithospheric thermal structure from “cold mantle and hot crust” before the Cretaceous to “hot mantle and cold crust” after the Cretaceous. The results also indicate that the basin experienced two large-scale rifting events. Therefore, this work may provide the thermal parameters for further investigations of the geodynamic evolution of eastern China.

  4. Determination of the Antarctic region active margin basement by using integration of the information coming from the multichannel seismic analysis and the magnetometry; Determinacao do embasamento da margen ativa da regiao Antartica pela integracao de informacoes provenientes da sismica multicanal e da magnetometria

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Luiz Carlos [Diretoria de Hidrografia e Navegacao, XX (Brazil); Gomes, Benedito Souza [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Gamboa, Luiz Antonio P. [Universidade Federal Fluminense, Niteroi, RJ (Brazil)

    1999-07-01

    Geophysical measurements were carried out in the Western Margin of the Antarctic Peninsula and Bransfield Strait by the Brazilian Antarctic Program during the summers of 1987 and 1988. The present work, using a continued seismic multi channel and magnetometry data profile crossing the area, intends to present a two-dimensional model of the interface sediment/basement and contribute to the understanding of the complex geology verified in the studying area. By this model, the main provinces of the are (Deep Ocean, South Shetland Trench, Accretionary Prism, Volcanic Arc South Shetland Islands and Bransfield Basin) could be determined. The seismic and magnetic measurements information when superposed can attribute more consistencies to the interpreted basement; although each method has its particular resolution. This way, when the seismic interpretation was not possible due to complex structures disposition, magnetic measurements could offer good estimation about basement depth. The fit between both methods (seismic and magnetic measurements) was reasonable both on the oceanic basin and in the region of Bransfield Strait. The magnetometry, as as well seismic, was sensible to the dip of Drake Plate at South Shetland Trench and the Intrusive occurrence at Bransfield Basin axis. (author)

  5. Seimic Images and Wide-angle Velocity constrains of the structure and geodynamic origin of the Gibraltar Arc system: A geological interpretation of the Gulf of Cadiz imbricated wedge, the western and eastern Alboran basins, and the South-Balearic basin.

    Science.gov (United States)

    Gracia, E.; Ranero, C. R.; Grevemeryer, I.; WestMed, TopoMed, , T. h. e.; cruise parties, Geomargen-1

    2012-04-01

    The current geodynamics of the region between north Africa and the Iberian Peninsula are dominated by the collision between the Eurasian and African plates. The ongoing deformation is mainly driven by the NW-SE, slow 4-5 mm/yr convergence that is partitioned across numerous faults and diffused through a broad region with no clear plate boundary defined. However, this region is characterized by the a series of geological structures that appear unrelated to the current dominant plate kinematics. The region is formed by the Gibraltar Arc system, an arcuate structure that is fronted by a large imbricated wedge of tectonically piled sediment slices in the Gulf of Cadiz, and a series of basins in the Mediterranean part of the region. The western, little deformed Alboran basin is located on the rear of the Gibraltar stacked units. The eastern Alboran basin is characterized by numerous volcanic ridges and is transitional to the South Balearic - North Algerian basin that displays a generally lower topography. The different tectonic elements are floored by a poorly known crystalline basement and their age, evolution and geodynamic origin is still strongly debated. Part of the uncertainty arises from the lack of deep penetrating modern geophysical data in much of the region. In the last 5 years, 3 successive cruise in the region have produced an extensive coverage of the different tectonic elements collection a series of wide angle seismic profiles in 2006 during the WestMed cruise with German R/V Meteor and two multichannel seismic reflection cruises with the R/V Sarmiento de Gamboa from mid September to late October (TopoMed-Gassis cruise) and late October to late November (Geomargen-1 cruise) 2011. In this contribution we present the new images of the tectonic structures and sedimentary basin and the wide-angle seismic velocity models across key regions of the system. We also present an interpretation of the entire system in the context of a geodynamic model of eastward

  6. Rifting to India-Asia Reactivation: Multi-phase Structural Evolution of the Barmer Basin, Rajasthan, northwest India

    Science.gov (United States)

    Kelly, M. J.; Bladon, A.; Clarke, S.; Najman, Y.; Copley, A.; Kloppenburg, A.

    2015-12-01

    The Barmer Basin, situated within the West Indian Rift System, is an intra-cratonic rift basin produced during Gondwana break-up. Despite being a prominent oil and gas province, the structural evolution and context of the rift within northwest India remains poorly understood. Substantial subsurface datasets acquired during hydrocarbon exploration provide an unrivalled tool to investigate the tectonic evolution of the Barmer Basin rift and northwest India during India-Asia collision. Here we present a structural analysis using seismic datasets to investigate Barmer Basin evolution and place findings within the context of northwest India development. Present day rift structural architectures result from superposition of two non-coaxial extensional events; an early mid-Cretaceous rift-oblique event (NW-SE), followed by a main Paleocene rifting phase (NE-SW). Three phases of fault reactivation follow rifting: A transpressive, Late Paleocene inversion along localised E-W and NNE-SSW-trending faults; a widespread Late Paleocene-Early Eocene inversion and Late Miocene-Present Day transpressive strike-slip faulting along NW-SE-trending faults and isolated inversion structures. A major Late Eocene-Miocene unconformity in the basin is also identified, approximately coeval with those identified within the Himalayan foreland basin, suggesting a common cause related to India-Asia collision, and calling into question previous explanations that are not compatible with spatial extension of the unconformity beyond the foreland basin. Although, relatively poorly age constrained, extensional and compressional events within the Barmer Basin can be correlated with regional tectonic processes including the fragmentation of Gondwana, the rapid migration of the Greater Indian continent, to subsequent collision with Asia. New insights into the Barmer Basin development have important implications not only for ongoing hydrocarbon exploration but the temporal evolution of northwest India.

  7. Basement Construction of Measurement Standardization for Thermal Property and Basement Preparation of Industrial Technology

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kweon Ho; Song, Kee Chan; Park, Chang Je

    2007-02-15

    There are three main categories in this report : 1)Basement construction of measurement standardization for nuclear material thermal property, 2) Reliability evaluation of measurement instrument, and 3) Standardization and industrial propagation.

  8. [Age structure and genetic diversity of Homatula pycnolepis in the Nujiang River basin].

    Science.gov (United States)

    Yue, Xing-Jian; Liu, Shao-Ping; Liu, Ming-Dian; Duan, Xin-Bin; Wang, Deng-Qiang; Chen, Da-Qing

    2013-08-01

    This study examined the age structure of the Loach, Homatula pycnolepis through the otolith growth rings in 204 individual specimens collected from the Xiaomengtong River of the Nujiang River (Salween River) basin in April, 2008. There were only two different age classes, 1 and 2 years of age-no 3 year olds were detected. The age structure of H. pycnolepis was simple. The complete mitochondrial DNA cytochrome b gene sequences (1140) of 80 individuals from 4 populations collected in the Nujiang River drainage were sequenced and a total of 44 variable sites were found among 4 different haplotypes. The global haplotype diversity (Hd) and nucleotide diversity (Pi) were calculated at 0.7595, 0.0151 respectively, and 0, 0 in each population, indicating a consistent lack of genetic diversity in each small population. There was obvious geographic structure in both the Nujiang River basin (NJB) group, and the Nanding River (NDR) group. The genetic distance between NJB and NDR was calculated at 0.0356, suggesting that genetic divergence resulted from long-term isolation of individual population. Such a simple age structure and a lack of genetic diversity in H. pycnolepis may potentially be due to small populations and locale fishing pressures. Accordingly, the results of this study prompt us to recommend that the NJB, NDR and Lancang River populations should be protected as three different evolutionary significant units or separated management units.

  9. Superimposed versus residual basin: The North Yellow Sea Basin

    Directory of Open Access Journals (Sweden)

    Wenyong Li

    2012-01-01

    Full Text Available The North Yellow Sea Basin is a Mesozoic and Cenozoic basin. Based on basin-margin facies, sedimentary thinning, size and shape of the basin and vitrinite reflectance, North Yellow Sea Basin is not a residual basin. Analysis of the development of the basin’s three structural layers, self-contained petroleum systems, boundary fault activity, migration of the Mesozoic–Cenozoic sedimentation centers, different basin structures formed during different periods, and superposition of a two-stage extended basin and one-stage depression basin, the North Yellow Sea Basin is recognized as a superimposed basin.

  10. Location and extent of Tertiary structures in Cook Inlet Basin, Alaska, and mantle dynamics that focus deformation and subsidence

    Science.gov (United States)

    Haeussler, Peter J.; Saltus, Richard W.

    2011-01-01

    This report is a new compilation of the location and extent of folds and faults in Cook Inlet Basin, Alaska. Data sources are previously published maps, well locations, and seismic-reflection data. We also utilize interpretation of new aeromagnetic data and some proprietary seismic-reflection data. Some structures are remarkably well displayed on frequency-filtered aeromagnetic maps, which are a useful tool for constraining the length of some structures. Most anticlines in and around the basin have at least shows of oil or gas, and some structures are considered to be seismically active. The new map better displays the pattern of faulting and folding. Deformation is greatest in upper Cook Inlet, where structures are oriented slightly counterclockwise of the basin bounding faults. The north ends of these structures bend to the northeast, which gives a pattern consistent with right-transpressional deformation.

  11. Characterization of the Cretaceous aquifer structure of the Meskala region of the Essaouira Basin, Morocco

    Science.gov (United States)

    Hanich, L.; Zouhri, L.; Dinger, J.

    2011-01-01

    The aquifer of early Cretaceous age in the Meskala region of the Essaouira Basin is defined by interpretation of geological drilling data of oil and hydrogeological wells, field measurement and analysis of in situ fracture orientations, and the application of a morphostructural method to identify lineaments. These analyzes are used to develop a stratigraphic-structural model of the aquifer delimited by fault zones of two principal orientations: NNE and WNW. These fault zones define fault blocks that range in area from 4 to 150km2. These blocks correspond either to elevated zones (horsts) or depressed zones (grabens). This structural setting with faults blocks of Meskala region is in accordance with the structure of the whole Essaouira Basin. Fault zones disrupt the continuity of the aquifer throughout the study area, create recharge and discharge zones, and create dip to the units from approximately 10?? to near vertical in various orientations. Fracture measurements and morphometric-lineament analyzes help to identify unmapped faults, and represent features important to groundwater hydraulics and water quality within fault blocks. The above geologic features will enable a better understanding of the behaviour and hydro-geo-chemical and hydrodynamics of groundwater in the Meskala aquifer. ?? 2010 Elsevier Ltd.

  12. Quantification of structural uncertainties in multi-scale models; case study of the Lublin Basin, Poland

    Science.gov (United States)

    Małolepszy, Zbigniew; Szynkaruk, Ewa

    2015-04-01

    The multiscale static modeling of regional structure of the Lublin Basin is carried on in the Polish Geological Institute, in accordance with principles of integrated 3D geological modelling. The model is based on all available geospatial data from Polish digital databases and analogue archives. Mapped regional structure covers the area of 260x80 km located between Warsaw and Polish-Ukrainian border, along NW-SE-trending margin of the East European Craton. Within the basin, the Paleozoic beds with coalbearing Carboniferous and older formations containing hydrocarbons and unconventional prospects are covered unconformably by Permo-Mesozoic and younger rocks. Vertical extent of the regional model is set from topographic surface to 6000 m ssl and at the bottom includes some Proterozoic crystalline formations of the craton. The project focuses on internal consistency of the models built at different scales - from basin (small) scale to field-scale (large-scale). The models, nested in the common structural framework, are being constructed with regional geological knowledge, ensuring smooth transition in the 3D model resolution and amount of geological detail. Major challenge of the multiscale approach to subsurface modelling is the assessment and consistent quantification of various types of geological uncertainties tied to those various scale sub-models. Decreasing amount of information with depth and, particularly, very limited data collected below exploration targets, as well as accuracy and quality of data, all have the most critical impact on the modelled structure. In deeper levels of the Lublin Basin model, seismic interpretation of 2D surveys is sparsely tied to well data. Therefore time-to-depth conversion carries one of the major uncertainties in the modeling of structures, especially below 3000 m ssl. Furthermore, as all models at different scales are based on the same dataset, we must deal with different levels of generalization of geological structures. The

  13. Age of Izu-Bonin-Mariana arc basement

    Science.gov (United States)

    Ishizuka, Osamu; Hickey-Vargas, Rosemary; Arculus, Richard J.; Yogodzinski, Gene M.; Savov, Ivan P.; Kusano, Yuki; McCarthy, Anders; Brandl, Philipp A.; Sudo, Masafumi

    2018-01-01

    Documenting the early tectonic and magmatic evolution of the Izu-Bonin-Mariana (IBM) arc system in the Western Pacific is critical for understanding the process and cause of subduction initiation along the current convergent margin between the Pacific and Philippine Sea plates. Forearc igneous sections provide firm evidence for seafloor spreading at the time of subduction initiation (52 Ma) and production of "forearc basalt". Ocean floor drilling (International Ocean Discovery Program Expedition 351) recovered basement-forming, low-Ti tholeiitic basalt crust formed shortly after subduction initiation but distal from the convergent margin (nominally reararc) of the future IBM arc (Amami Sankaku Basin: ASB). Radiometric dating of this basement gives an age range (49.3-46.8 Ma with a weighted average of 48.7 Ma) that overlaps that of basalt in the present-day IBM forearc, but up to 3.3 m.y. younger than the onset of forearc basalt activity. Similarity in age range and geochemical character between the reararc and forearc basalts implies that the ocean crust newly formed by seafloor spreading during subduction initiation extends from fore- to reararc of the present-day IBM arc. Given the age difference between the oldest forearc basalt and the ASB crust, asymmetric spreading caused by ridge migration might have taken place. This scenario for the formation of the ASB implies that the Mesozoic remnant arc terrane of the Daito Ridges comprised the overriding plate at subduction initiation. The juxtaposition of a relatively buoyant remnant arc terrane adjacent to an oceanic plate was more favourable for subduction initiation than would have been the case if both downgoing and overriding plates had been oceanic.

  14. 13 Morphometric Analysis of Ogunpa and Ogbere Drainage Basins ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    The paper analysed the morphometric parameters of Ogbere and Ogunpa drainage basins located on basement complex rock in ... properties of Ogunpa drainage basin are likely to induce high magnitude flood compared to morphometric properties of Ogbere ..... Bs = VI/HE where Bs = Basin slope, VI = Vertical Interval and.

  15. Site effects and soil-structure resonance study in the Kobarid basin (NW Slovenia using microtremors

    Directory of Open Access Journals (Sweden)

    A. Gosar

    2010-04-01

    Full Text Available The town of Kobarid is located in one of three areas with the highest seismic hazard in Slovenia. It was hit by several 1976–1977 Friuli sequence earthquakes and recently by the 1998 and 2004 Krn Mountains earthquakes which caused damage of intensity up to VII EMS-98 scale. The town is located in a small basin filled with heterogeneous glaciofluvial Quaternary sediments in which site effects due to soft sediments are expected. The existing microzonation which is based on surface geological data only is inadequate, and no borehole or geophysical data are available in the basin that would allow a modelling approach of site effects assessment. The microtremor horizontal-to-vertical spectral ratio (HVSR method was therefore applied in order to assess the fundamental frequency of the sediments. Investigations were performed on a 100×100 m dense grid and 106 free-field measurements acquired. Clear HVSR peaks were obtained in the majority of the surveyed area. The eastern part of the basin is characterized by two well separated peaks which indicate distinct shallow and deep impedance contrasts. The iso-frequency map of sediments shows a distribution in a broad range of 1.8–22.2 Hz. The observed frequencies can be related to the total thickness of Quaternary sediments (sand, gravel in the western part of the basin only. They are deposited over bedrock built of Cretaceous flysch. In the eastern part the obtained fundamental frequencies are influenced by the presence of a shallow conglomerate layer inside sandy gravel or lacustrine chalk. The extent of these layers was not known before. Microtremor measurements were also performed inside 19 characteristic buildings of various heights (from two to four stories, and longitudinal and transverse fundamental frequencies determined from amplitude spectra. A potential of soil-structure resonance was assessed by comparing building frequencies with the free-field sediments frequencies derived from the iso

  16. Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

    Science.gov (United States)

    Stamos, Christina L.; Christensen, Allen H.; Langenheim, Victoria

    2017-07-19

    structures that could affect groundwater flow between the groundwater basins in the study area, gravity data were collected using more closely spaced measurements in September 2014. Groundwater-level data was gathered and collected from March 2014 through March 2015 to determine depth to water and direction of groundwater flow. The gravity and groundwater-level data showed that the saturated thickness of the alluvium was about 2,000 feet thick to the east and about 130 feet thick above the northward-trending basement ridge near Llano, California. Although it was uncertain whether the basement ridge affects the groundwater system, a potential barrier to groundwater flow could be created if the water table fell below the altitude of the basement ridge, effectively causing the area to the west of the basement ridge to become hydraulically isolated from the area to the east. In addition, the direction of regional-groundwater flow likely will be influenced by future changes in the number and distribution of pumping wells and the thickness of the saturated alluvium from which water is withdrawn. Three-dimensional animations were created to help visualize the relation between the basins’ basement topography and the groundwater system in the area. Further studies that could help to more accurately define the basins and evaluate the groundwater-flow system include exploratory drilling of multi-depth monitoring wells; collection of depth-dependent water-quality samples; and linking together existing, but separate, groundwater-flow models from the Antelope Valley and El Mirage Valley groundwater basins into a single, calibrated groundwater-flow model.

  17. C-O-H-N fluids circulations and graphite precipitation in reactivated Hudsonian shear zones during basement uplift of the Wollaston-Mudjatik Transition Zone: Example of the Cigar Lake U deposit

    Science.gov (United States)

    Martz, Pierre; Cathelineau, Michel; Mercadier, Julien; Boiron, Marie-Christine; Jaguin, Justine; Tarantola, Alexandre; Demacon, Mickael; Gerbeaud, Olivier; Quirt, David; Doney, Amber; Ledru, Patrick

    2017-12-01

    Graphitic shear zones are spatially associated with unconformity-related uranium deposits that are located around the unconformity between the strata of the Paleo- to Mesoproterozoic Athabasca Basin (Saskatchewan, Canada) and its underlying Archean to Paleoproterozoic basement. The present study focuses on basement-hosted ductile-brittle graphitic shear zones near the Cigar Lake U deposit, one of the largest unconformity-related U deposits. The goal of the study is to decipher the pre-Athabasca Basin fluid migration history recorded within such structures and its potential role on the formation of such exceptional deposit. Dominantly C-O-H(-N) metamorphic fluids have been trapped in Fluid Inclusion Planes (FIPs) in magmatic quartz within ductile-brittle graphitic shear zones active during retrograde metamorphism associated with the formation of the Wollaston-Mudjatik Transition Zone (WMTZ) between ca. 1805 and 1720 Ma. Such fluids show a compositional evolution along the retrograde path, from a dense and pure CO2 fluid during the earliest stages, through a lower density CO2 ± CH4-N2 (± H2O) fluid and, finally, to a very low density CH4-N2 fluid. Statistical study of the orientation, distribution, proportion, and chemical characterization of the FIPs shows that: i) CO2 (δ13CCO2 around - 9‰ PDB) from decarbonation reactions and/or partial water-metamorphic graphite equilibrium initially migrated regionally and pervasively under lithostatic conditions at about 500 to 800 °C and 150 to 300 MPa. Such P-T conditions attest to a high geothermal gradient of around 60 to 90 °C/km, probably related to rapid exhumation of the basement or a large-scale heat source. ii) Later brittle reactivation of the shear zone at around 450 °C and 25-50 MPa favored circulation of CO2-CH4-N2(± H2O) fluids in equilibrium with metamorphic graphite (δ13CCO2 around - 14‰) under hydrostatic conditions and only within the shear zones. Cooling of these fluids and the water uptake linked

  18. Large Sanjiang basin groups outside of the Songliao Basin Meso-Senozoic Tectonic-sediment evolution and hydrocarbon accumulation

    Science.gov (United States)

    Zheng, M.; Wu, X.

    2015-12-01

    The basis geological problem is still the bottleneck of the exploration work of the lager Sanjiang basin groups. In general terms, the problems are including the prototype basins and basin forming mechanism of two aspects. In this paper, using the field geological survey and investigation, logging data analysis, seismic data interpretation technical means large Sanjiang basin groups and basin forming mechanism of the prototype are discussed. Main draw the following conclusions: 1. Sanjiang region group-level formation can be completely contrasted. 2. Tension faults, compressive faults, shear structure composition and structure combination of four kinds of compound fracture are mainly developed In the study area. The direction of their distribution can be divided into SN, EW, NNE, NEE, NNW, NWW to other groups of fracture. 3. Large Sanjiang basin has the SN and the EW two main directions of tectonic evolution. Cenozoic basins in Sanjiang region in group formation located the two tectonic domains of ancient Paleo-Asian Ocean and the Pacific Interchange. 4. Large Sanjiang basin has experienced in the late Mesozoic tectonic evolution of two-stage and nine times. The first stage, developmental stage basement, they are ① Since the Mesozoic era and before the Jurassic; ② Early Jurassic period; The second stage, cap stage of development, they are ③ Late Jurassic depression developmental stages of compression; ④ Early Cretaceous rifting stage; ⑤ depression in mid-Early Cretaceous period; ⑥ tensile Early Cretaceous rifting stage; ⑦ inversion of Late Cretaceous tectonic compression stage; ⑧ Paleogene - Neogene; ⑨ After recently Ji Baoquan Sedimentary Ridge. 5. Large Sanjiang basin group is actually a residual basin structure, and Can be divided into left - superimposed (Founder, Tangyuan depression, Hulin Basin), residual - inherited type (Sanjiang basin), residual - reformed (Jixi, Boli, Hegang basin). there are two developed depression and the mechanism

  19. Phylogeography and Population Genetic Structure of Amur Grayling Thymallus grubii in the Amur Basin

    Science.gov (United States)

    Ma, Bo; Lui, Tingting; Zhang, Ying; Chen, Jinping

    2012-01-01

    Amur grayling, Thymallus grubii, is an important economic cold freshwater fish originally found in the Amur basin. Currently, suffering from loss of habitat and shrinking population size, T. grubii is restricted to the mountain river branches of the Amur basin. In order to assess the genetic diversity, population genetic structure and infer the evolutionary history within the species, we analysised the whole mitochondrial DNA control region (CR) of 95 individuals from 10 rivers in China, as well as 12 individuals from Ingoda/Onon and Bureya River throughout its distribution area. A total of 64 variable sites were observed and 45 haplotypes were identified excluding sites with gaps/missing data. Phylogenetic analysis was able to confidently predict two subclade topologies well supported by maximum-parsimony and Bayesian methods. However, basal branching patterns cannot be unambiguously estimated. Haplotypes from the mitochondrial clades displayed local homogeneity, implying a strong population structure within T. grubii. Analysis of molecular variance detected significant differences among the different geographical rivers, suggesting that T. grubii in each river should be managed and conserved separately. PMID:25049647

  20. Verification of structural control on landforms in the transition zone between Pannonian Basin and Eastern Alps

    Science.gov (United States)

    Kovács, Gábor; Fodor, László; Kövér, Szilvia; Molnár, Gábor; Székely, Balázs; Timár, Gábor; Telbisz, Tamás

    2013-04-01

    Steep, rectilinear slopes are frequently considered as being controlled by structural elements. A number of studies automatically take the linearity of landforms as prove for structural, most frequently fault control. However, this logical but not unequivocal conclusion needs careful verification, because divers geomorphic process alone can also result in straight valley sides, river stretches etc. Structural control on such landforms can be difficult to prove, because of poor outcrop conditions, and the lack of adequate surface and subsurface data sets. It is particularly true for landforms within the Pannonian Basin, central Europe, which offers poor outcrops for both geological and geomorphological analyses, landforms are vegetated and sometimes anthropogenetically modified. Structural control can be derived from either inherited elements or active deformation. In the former case, the controlling structural element was formed somewhat before the time of landscape evolution steps. Divers denudation process can passively exhume the structure, which, on its two sides, has rocks with different resistance against erosion; this led to contrasting rate of denudation in the two fault blocks. In that scenario, the spatial coincidence, similarity in direction of the older structural element and the landform should be carried out. Demonstration of active (neotectonic) control on landform can be more complicated, while the young age of deformation could be hard to prove. Although a number of geomorphic indices can be evaluated and used as indications for active deformation, undoubted demonstration of the age of the structure and thus the controlled landform remains elusive. Demonstration of structural control on a specific landform may involve variable methods and data sets. One successful example form the Pannonian Basin, Ruszkiczay-Rüdiger et al. (2007, 2009) used a complex surface and subsurface data sets (to infer structurally constrained landforms). In our study we

  1. Extensional Tectonics and Sedimentary Architecture Using 3-D Seismic Data: An Example from Hydrocarbon-Bearing Mumbai Offshore Basin, West Coast of India

    Science.gov (United States)

    Mukhopadhyay, D. K.; Bhowmick, P. K.; Mishra, P.

    2016-12-01

    In offshore sedimentary basins, analysis of 3-D seismic data tied with well log data can be used to deduce robust isopach and structure contour maps of different stratigraphic formations. The isopach maps give depocenters whereas structure contour maps give structural relief at a specific time. Combination of these two types of data helps us decipher horst-graben structures, sedimentary basin architecture and tectono-stratigraphic relations through Tertiary time. Restoration of structural cross sections with back-stripping of successively older stratigraphic layers leads to better understand tectono-sedimentary evolution of a basin. The Mumbai (or Bombay) Offshore Basin is the largest basin off the west coast of India and includes Bombay High giant oil/gas field. Although this field was discovered in 1974 and still producing, the basin architecture vis-à-vis structural evolution are not well documented. We take the approach briefly outlined above to study in detail three large hydrocarbon-bearing structures located within the offshore basin. The Cretaceous Deccan basalt forms the basement and hosts prodigal thickness (> 8 km at some localities) of Tertiary sedimentary formations.A two stage deformation is envisaged. At the first stage horst and graben structures formed due to approximately E-W extensional tectonics. This is most spectacularly seen at the basement top level. The faults associated with this extension strike NNW. At the second stage of deformation a set of ENE-striking cross faults have developed leading to the formation of transpressional structures at places. High rate of early sedimentation obliterated horst-graben architecture to large extent. An interesting aspect emerges is that the all the large-scale structures have rather low structural relief. However, the areal extent of such structures are very large. Consequently, these structures hold commercial quantities of oil/gas.

  2. Structural interpretation of the area around the Cays - Quitasueno and Serrana, in the Caribbean, coast away from Colombia

    International Nuclear Information System (INIS)

    Munar, F

    2000-01-01

    The Caribbean basin has been poorly explored and poses a wide array of geological questions, due to its uncertain stratigraphic relations, its structural frame and the nature of its basement related to the islands. By interpreting 1.700 km seismic lines, from the Ecopetrol Caribbean surveys, Cayos 77 and Cayos 82, and by tightening two wells, Miskito 1 and Miskito 2, in the area of Cays (lower Nicaragua rise), north of the Colombia Basin, we determined the stratigraphic position of the basement B and found out two trends NE-SW and NW-SE for the Quitasueno and Serrana Cays, in a horst and Graben style. In addition to that, the facies for the basement are for the most part igneous and from an exploration point of view, it gives the opportunity for a good seal

  3. Velocity and Q Structure of the Quaternary Sediment in Bohai Basin, China

    Science.gov (United States)

    Chong, J.; Luo, Y.; Ni, S.; Chen, Y.

    2008-12-01

    Heavily populated by Beijing and Tianjin cities, Bohai Basin is a seismically active Cenozoic basin suffering from huge lost by devastating earthquakes, such as Tangshan earthquake. There have been some studies about three dimensional structure of the lithosphere in this region; however the attenuation (Qp and Qs) of the surfacial quaternary sediment has not been studied at natural seismic frequency (1-10HZ), which is crucial to earthquake hazards study. Borehole seismic records of micro earthquake provide us a good way to study the velocity and Q attenuation of the surfacial structure (0-500m). We found that there are two pulses well separated with simple waveforms while analyzing borehole seismic records from the 2006 Mw4.9 WenAn earthquake sequence. Then we performed waveform modeling with Generalized Ray Theory (GRT) to confirm that the two pulses are direct wave and surface reflected wave, and found that the average Vp and Vs of the top 300m in this region are about 1.83km/s and 0.42km/s while Vp/Vs falls in a high value of 4.4. We also modeled surface reflected wave with Propagating Matrix method to study the value of Qs and the surfacial velocity structure. Our modeling indicates that Qs should be larger than 30, even up to 100, this is quite larger than the typically assumed extremely low Q (~=10) found by Hauksson et al (Hauksson et al, 1987; Blakeslee and Malin, 1991) but much similar to that of Langston (2002). Also, the velocity gradient just beneath the free surface (0-50m) is very large and velocity increases slowly at larger depth. Our modeling demonstrates the value of borehole seismic records in resolving shallow velocity and attenuation structure, and hence their significance in earthquake hazard simulation.

  4. The Concertina Coast: the role of basement inheritance during repeated reactivation events along Australia's northern margin since the Permian

    Science.gov (United States)

    Keep, Myra; Gartrell, Anthony

    2017-04-01

    The present day configuration of Australia's northern margin includes a series of Phanerozoic sedimentary basins forming the North West Shelf. Their polyphase history, dominantly extensional, and closely associated with the breakup of Eastern Gondwana, includes the early formation of intracratonic basins (from the mid-Devonian), overprinted by Permo-Carboniferous rifting that generated the dominant NE-trending structural trends that persist to the present-day. Subsequent Mesozoic extension, associated with the formation of abyssal plains, further refined the margin, creating additional depocentres. During this polyphase rift history, a number of periods of inversion have punctuated the margin. These include a Carboniferous event (the Meda Transpression), a late Permian to Early Triassic event, sometimes referred to as the Bedout Movement (possibly transtensional), and two events, one in the Middle to Late Triassic, followed by another in the Late Triassic to Early Jurassic, often referred to as the Fitzroy events. These various events, recorded locally, caused inversion, folding, uplift and erosion where documented, with the Fitzroy events described as transpressional, resulting from right-lateral oblique inversion. Subsequent inversion during the Cretaceous, also attributed to dextral transpression, caused long wavelength folding and fault inversion in some basins. Whereas the effects of earlier inversions are somewhat sporadic across the North West Shelf, the effects of Neogene inversion have been documented across both the active and passive segments of the present day North West Shelf, and also appear to be strongly controlled by right-lateral oblique reactivation mechanisms, with associated seismicity and focal mechanism solutions. The history of the North West Shelf therefore includes 6 discrete episodes of reactivation and inversion, apparently strongly dominated by oblique mechanisms, which punctuate the long, multi-phase extensional history. Whereas

  5. Joint inversion of high resolution S-wave velocity structure underneath North China Basin

    Science.gov (United States)

    Yang, C.; Li, G.; Niu, F.

    2017-12-01

    North China basin is one of earthquake prone areas in China. Many devastating earthquakes occurred in the last century and before, such as the 1937 M7.0 Heze Earthquake in Shandong province, the 1966 M7.2 Xingtai Earthquake and 1976 Tangshan Earthquake in Hebei province. Knowing the structure of the sediment cover is of great importance to predict strong ground motion caused by earthquakes. Unconsolidated sediments are loose materials, ranging from clay to sand to gravel. Earthquakes can liquefy unconsolidated sediments, thus knowing the distribution and thickness of the unconsolidated sediments has significant implication in seismic hazard analysis of the area. Quantitative estimates of the amount of extension of the North China basin is important to understand the thinning and evolution of the eastern North China craton and the underlying mechanism. In principle, the amount of lithospheric stretching can be estimated from sediment and crustal thickness. Therefore an accurate estimate of the sediment and crustal thickness of the area is also important in understanding regional tectonics. In this study, we jointly invert the Rayleigh wave phase-velocity dispersion and Z/H ratio data to construct a 3-D S-wave velocity model beneath North China area. We use 4-year ambient noise data recorded from 249 temporary stations, and 139 earthquake events to extract Rayleigh wave Z/H ratios. The Z/H ratios obtained from ambient noise data and earthquake data show a good agreement within the overlapped periods. The phase velocity dispersion curve was estimated from the same ambient noise data. The preliminary result shows a relatively low Z/H ratio and low velocity anomaly at the shallow part of sediment basins.

  6. Thermal-Mechanical Regime beneath Tarim Basin, Northwestern China and its Implications for Cenozoic Tectonics

    Science.gov (United States)

    Liu, S.; Wang, L.

    2005-12-01

    As one of the super-large scale sedimentary basins in China, the Tarim basin is also the strategic basement for Chinese `Natural gas transportation from west to east' project. To know its thermal regime is vital for understanding the deformation and oil gas resource in Tarim basin. Integrated the abundant data of geotemperature and rock thermophysical parameters collected and measured in the basin with corresponding geothermal modeling, here we present the characteristics of geotemperature field, thermal evolution and lithospheric thermo-rheological structure of the Tarim basin, along with the implications for formation and deformation of basin and hydrocarbon reservoir. Our results show that the average present-day heat flow of the basin is about 45 mW/m2 and 18-20°/km for geotemperature gradient, respectively. The basin is characterized by lower temperature in a whole. Lateral heterogeneities exist for the distribution of geotemperature field in the basin. The structural units of basin differ much in the geothermal features; generally, the depression areas are of relatively low geotemperature while high for those uplifts and highs in the basin. Thermal evolution modeling of the basin indicated that it has experienced four different phases since basin formation as follows: high heat flow phase from Sinian to Ordovician, thermal attenuation phase during Silurian to late Paleozoic, then stable thermal evolution phase in Mesozoic, and flexural deformation of lithosphere in Cenozoic. The thickness of the thermal lithosphere of basin is 168-192 km, and 25-28km for the crustal brittle-ductile transition depth; the total lithospheric strength is 1.6-7.8*10**13 N/m. The lithosphere beneath basin is characterized by the rigid block with low temperature but large strength, and deform in a whole. Responded to the far field effect of the Cenozoic India-Eurasia collision, the lithosphere beneath Tarim basin is characterized by flexure deformation, resulting in the intensive

  7. A structural scheme proposal derived from geophysical data in the epicentral area of the Boumerdes (Algeria) earthquake of May 21, 2003

    Science.gov (United States)

    Samai, Saddek; Idres, Mouloud; Ouyed, Merzouk; Bourmatte, Amar; Boughacha, Mohamed Salah; Bezzeghoud, Mourad; Borges, José Fernando

    2017-09-01

    In this study, we processed and interpreted gravity and aeromagnetic data of the epicentral area of the Boumerdes earthquake (May 21, 2003). The joint interpretation of both data allowed the development of a structural scheme that shows the basement undulations offshore and onshore. The shape of the eastern part of the Mitidja Basin is better defined; its northern edge is represented by a large ;sub-circular; uplifted basement located offshore. The rise of this basement indicates that this basin does not extend towards the sea. At the eastern part of the study area, aeromagnetic data have revealed that the Sid-Ali-Bounab basement is individualized in a ;sub-circular; shape, while the Dellys basement, located in the NE part, is elongated in the NE-SW direction and extends offshore. The aeromagnetic data also highlighted two EW basement uplifts which divide Isser depression into three parts. The northern part of this depression extends offshore. The southernmost uplift is an extension of the Thenia Fault (TF), suggesting the continuity of this fault to the east. It is important to note that the active Reghaia Fault (RF), which runs through the Boudouaou and Reghaia urban centers, is bounded by two faults suggesting that its length does not exceed 12 km. Moreover, alluvial terraces observed west of the active Zemmouri Fault (ZF) are in agreement with the reverse component of this fault.

  8. The geostatistical approach for structural and stratigraphic framework analysis of offshore NW Bonaparte Basin, Australia

    International Nuclear Information System (INIS)

    Wahid, Ali; Salim, Ahmed Mohamed Ahmed; Yusoff, Wan Ismail Wan; Gaafar, Gamal Ragab

    2016-01-01

    Geostatistics or statistical approach is based on the studies of temporal and spatial trend, which depend upon spatial relationships to model known information of variable(s) at unsampled locations. The statistical technique known as kriging was used for petrophycial and facies analysis, which help to assume spatial relationship to model the geological continuity between the known data and the unknown to produce a single best guess of the unknown. Kriging is also known as optimal interpolation technique, which facilitate to generate best linear unbiased estimation of each horizon. The idea is to construct a numerical model of the lithofacies and rock properties that honor available data and further integrate with interpreting seismic sections, techtonostratigraphy chart with sea level curve (short term) and regional tectonics of the study area to find the structural and stratigraphic growth history of the NW Bonaparte Basin. By using kriging technique the models were built which help to estimate different parameters like horizons, facies, and porosities in the study area. The variograms were used to determine for identification of spatial relationship between data which help to find the depositional history of the North West (NW) Bonaparte Basin

  9. The geostatistical approach for structural and stratigraphic framework analysis of offshore NW Bonaparte Basin, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Wahid, Ali, E-mail: ali.wahid@live.com; Salim, Ahmed Mohamed Ahmed, E-mail: mohamed.salim@petronas.com.my; Yusoff, Wan Ismail Wan, E-mail: wanismail-wanyusoff@petronas.com.my [Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 32610 Tronoh, Perak (Malaysia); Gaafar, Gamal Ragab, E-mail: gaafargr@gmail.com [Petroleum Engineering Division, PETRONAS Carigali Sdn Bhd, Kuala Lumpur (Malaysia)

    2016-02-01

    Geostatistics or statistical approach is based on the studies of temporal and spatial trend, which depend upon spatial relationships to model known information of variable(s) at unsampled locations. The statistical technique known as kriging was used for petrophycial and facies analysis, which help to assume spatial relationship to model the geological continuity between the known data and the unknown to produce a single best guess of the unknown. Kriging is also known as optimal interpolation technique, which facilitate to generate best linear unbiased estimation of each horizon. The idea is to construct a numerical model of the lithofacies and rock properties that honor available data and further integrate with interpreting seismic sections, techtonostratigraphy chart with sea level curve (short term) and regional tectonics of the study area to find the structural and stratigraphic growth history of the NW Bonaparte Basin. By using kriging technique the models were built which help to estimate different parameters like horizons, facies, and porosities in the study area. The variograms were used to determine for identification of spatial relationship between data which help to find the depositional history of the North West (NW) Bonaparte Basin.

  10. Accelerating repaired basement membrane after bevacizumab treatment on alkali-burned mouse cornea

    Science.gov (United States)

    Lee, Koon-Ja; Lee, Ji-Young; Lee, Sung Ho; Choi, Tae Hoon

    2013-01-01

    To understand the corneal regeneration induced by bevacizumab, we investigated the structure changes of stroma and basement membrane regeneration. A Stick soaked in 0.5 N NaOH onto the mouse cornea and 2.5 mg/ml of bevacizumab was delivered into an alkali-burned cornea (2 μl) by subconjunctival injections at 1 hour and 4 days after injury. At 7 days after injury, basement membrane regeneration was observed by transmission electron microscope. Uneven and thin epithelial basement membrane, light density of hemidesmosomes, and edematous collagen fibril bundles are shown in the alkali-burned cornea. Injured epithelial basement membrane and hemidesmosomes and edematous collagen fibril bundles resulting from alkali-burned mouse cornea was repaired by bevacizumab treatment. This study demonstrates that bevacizumab can play an important role in wound healing in the cornea by accelerating the reestablishment of basement membrane integrity that leads to barriers for scar formation. [BMB Reports 2013; 46(4): 195-200] PMID:23615260

  11. Near surface velocity and Q S structure of the Quaternary sediment in Bohai basin, China

    Science.gov (United States)

    Chong, Jiajun; Ni, Sidao

    2009-10-01

    Heavily populated by Beijing and Tianjin cities, Bohai basin is a seismically active Cenozoic basin suffering from huge lost by devastating earthquakes, such as Tangshan earthquake. The attenuation ( Q P and Q S) of the surficial Quaternary sediment has not been studied at natural seismic frequency (1-10 Hz), which is crucial to earthquake hazards study. Borehole seismic records of micro earthquake provide us a good way to study the velocity and attenuation of the surficial structure (0-500 m). We found that there are two pulses well separated with simple waveforms on borehole seismic records from the 2006 M W4.9 Wen’an earthquake sequence. Then we performed waveform modeling with generalized ray theory (GRT) to confirm that the two pulses are direct wave and surface reflected wave, and found that the average ν P and ν S of the top 300 m in this region are about 1.8 km/s and 0.42 km/s, leading to high ν P/ ν S ratio of 4.3. We also modeled surface reflected wave with propagating matrix method to constrain Q S and the near surface velocity structure. Our modeling indicates that Q S is at least 30, or probably up to 100, much larger than the typically assumed extremely low Q (˜10), but consistent with Q S modeling in Mississippi embayment. Also, the velocity gradient just beneath the free surface (0-50 m) is very large and velocity increases gradually at larger depth. Our modeling demonstrates the importance of borehole seismic records in resolving shallow velocity and attenuation structure, and hence may help in earthquake hazard simulation.

  12. Geologic structure of the Yucaipa area inferred from gravity data, San Bernardino and Riverside Counties, California

    Science.gov (United States)

    Mendez, Gregory O.; Langenheim, V.E.; Morita, Andrew; Danskin, Wesley R.

    2016-09-30

    In the spring of 2009, the U.S. Geological Survey, in cooperation with the San Bernardino Valley Municipal Water District, began working on a gravity survey in the Yucaipa area to explore the three-dimensional shape of the sedimentary fill (alluvial deposits) and the surface of the underlying crystalline basement rocks. As water use has increased in pace with rapid urbanization, water managers have need for better information about the subsurface geometry and the boundaries of groundwater subbasins in the Yucaipa area. The large density contrast between alluvial deposits and the crystalline basement complex permits using modeling of gravity data to estimate the thickness of alluvial deposits. The bottom of the alluvial deposits is considered to be the top of crystalline basement rocks. The gravity data, integrated with geologic information from surface outcrops and 51 subsurface borings (15 of which penetrated basement rock), indicated a complex basin configuration where steep slopes coincide with mapped faults―such as the Crafton Hills Fault and the eastern section of the Banning Fault―and concealed ridges separate hydrologically defined subbasins.Gravity measurements and well logs were the primary data sets used to define the thickness and structure of the groundwater basin. Gravity measurements were collected at 256 new locations along profiles that totaled approximately 104.6 km (65 mi) in length; these data supplemented previously collected gravity measurements. Gravity data were reduced to isostatic anomalies and separated into an anomaly field representing the valley fill. The ‘valley-fill-deposits gravity anomaly’ was converted to thickness by using an assumed, depth-varying density contrast between the alluvial deposits and the underlying bedrock.To help visualize the basin geometry, an animation of the elevation of the top of the basement-rocks was prepared. The animation “flies over” the Yucaipa groundwater basin, viewing the land surface

  13. Isotropic Versus Bipolar Functionalized Biomimetic Artificial Basement Membranes and Their Evaluation in Long-Term Human Cell Co-Culture.

    Science.gov (United States)

    Rossi, Angela; Wistlich, Laura; Heffels, Karl-Heinz; Walles, Heike; Groll, Jürgen

    2016-08-01

    In addition to dividing tissues into compartments, basement membranes are crucial as cell substrates and to regulate cellular behavior. The development of artificial basement membranes is indispensable for the ultimate formation of functional engineered tissues; however, pose a challenge due to their complex structure. Herein, biodegradable electrospun polyester meshes are presented, exhibiting isotropic or bipolar bioactivation as a biomimetic and biofunctional model of the natural basement membrane. In a one-step preparation process, reactive star-shaped prepolymer additives, which generate a hydrophilic fiber surface, are electrospun with cell-adhesion-mediating peptides, derived from major components of the basement membrane. Human skin cells adhere to the functionalized meshes, and long-term co-culture experiments confirm that the artificial basement membranes recapitulate and preserve tissue specific functions. Several layers of immortalized human keratinocytes grow on the membranes, differentiating toward the surface and expressing typical epithelial markers. Fibroblasts migrate into the reticular lamina mimicking part of the mesh. Both cells types begin to produce extracellular matrix proteins and to remodel the initial membrane. It is shown at the example of skin that the artificial basement membrane design provokes biomimetic responses of different cell types and can thus be used as basis for the future development of basement membrane containing tissues. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Population Structure of Columbia River Basin Chinook Salmon and Steelhead Trout, Technical Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Brannon, E.L.; National Science Foundation (U.S.)

    2002-08-01

    The population structure of chinook salmon and steelhead trout is presented as an assimilation of the life history forms that have evolved in synchrony with diverse and complex environments over their Pacific range. As poikilotherms, temperature is described as the overwhelming environmental influence that determines what life history options occur and where they are distributed. The different populations represent ecological types referred to as spring-, summer-, fall, and winter-run segments, as well as stream- and ocean-type, or stream- and ocean-maturing life history forms. However, they are more correctly described as a continuum of forms that fall along a temporal cline related to incubation and rearing temperatures that determine spawn timing and juvenile residence patterns. Once new habitats are colonized, members of the founding populations spread through adaptive evolution to assume complementary life history strategies. The related population units are collectively referred to as a metapopulation, and members most closely associated within common temporal and geographic boundaries are designated as first-order metapopulations. Population structure of chinook salmon and steelhead in the Columbia Basin, therefore, is the reflection of the genetic composition of the founding source or sources within the respective region, shaped by the environment, principally temperature, that defines life history evolutionary strategy to maximize fitness under the conditions delineated. The complexity of structure rests with the diversity of opportunities over the elevations that exist within the Basin. Consistent with natural selection, rather than simply attempting to preserve populations, the challenge is to provide opportunities to expand their range to new or restored habitat that can accommodate genetic adaptation as directional environmental changes are elaborated. Artificial propagation can have a critical role in this process, and the emphasis must be placed on

  15. Seismically-generated hydroplastic deformation structures in the Late Miocene lacustrine deposits of the Malatya Basin, eastern Turkey

    Science.gov (United States)

    Koç Taşgın, Calibe

    2011-04-01

    The Late Miocene succession of continental deposits in the Malatya Basin, eastern Anatolia, comprises alluvial-fan, lacustrine and fluvial facies associations. This fault-bounded basin formed in a tectonically active region, notorious for strong earthquakes still today. The lacustrine deposits in the northern part of the basin show several isolated horizons of soft-sediment deformation, including such structures as slump folds, load and flame features, sand dikes and small-scale synsedimentary reverse faults with associated folds. There is no direct evidence supporting instabilities due to unequal loading or overloading, wave-induced cyclical and/or impulsive stresses, sudden changes in groundwater level or bioturbation capable of producing these deformation structures. The soft-sediment deformation structures described in the lacustrine deposits are interpreted as having developed as a result of seismic activity taking place along the Malatya fault zone, based on the tectonic setting of the basin, the lateral extent of the soft-sediment deformation structures over hundreds of metres, their confinement by undeformed layers, the presence of complex structures, and similarities with structures interpreted as being seismically induced in other areas and those obtained experimentally.

  16. Reliability of residential basements as blast shelters

    International Nuclear Information System (INIS)

    Longinow, A.; Mohammadi, J.

    1983-01-01

    This paper describes an analysis method for predicting the probability of failure of a wood-framed basement when subjected to a static, uniformly distributed load. The analysis considers the primary failure modes of each framing member and determines the probability of failure for each mode acting alone. The failure probability of the system as a whole is then bounded. The upper bound is determined on the assumption that the failure modes are independent, while the lower bound is determined on the assumption that the failure modes are perfectly correlated. The analysis is described with reference to an example problem

  17. Temporal change in biological community structure in the Fountain Creek basin, Colorado, 2001-2008

    Science.gov (United States)

    Zuellig, Robert E.; Bruce, James F.; Stogner, Sr., Robert W.

    2010-01-01

    In 2001, the U.S. Geological Survey, in cooperation with Colorado Springs City Engineering, began a study to better understand the relations between environmental characteristics and biological communities in the Fountain Creek basin in order to aide water-resource management and guide future monitoring activities. To accomplish this task, environmental (streamflow, habitat, and water chemistry) and biological (fish and macroinvertebrate) data were collected annually at 24 sites over a 6- or 8-year period (fish, 2003 to 2008; macroinvertebrates, 2001 to 2008). For this report, these data were first analyzed to determine the presence of temporal change in macroinvertebrate and fish community structure among years using nonparametric multivariate statistics. Where temporal change in the biological communities was found, these data were further analyzed using additional nonparametric multivariate techniques to determine which subset of selected streamflow, habitat, or water-chemistry variables best described site-specific changes in community structure relative to a gradient of urbanization. This study identified significant directional patterns of temporal change in macroinvertebrate and fish community structure at 15 of 24 sites in the Fountain Creek basin. At four of these sites, changes in environmental variables were significantly correlated with the concurrent temporal change identified in macroinvertebrate and fish community structure (Monument Creek above Woodmen Road at Colorado Springs, Colo.; Monument Creek at Bijou Street at Colorado Springs, Colo.; Bear Creek near Colorado Springs, Colo.; Fountain Creek at Security, Colo.). Combinations of environmental variables describing directional temporal change in the biota appeared to be site specific as no single variable dominated the results; however, substrate composition variables (percent substrate composition composed of sand, gravel, or cobble) collectively were present in 80 percent of the environmental

  18. The Northeastern Brazil and Gabon Basins: a Double Rifting System Associated with Multiple Crustal Detachment Surfaces

    Science.gov (United States)

    Castro, Augusto Canellas M., Jr.

    1987-12-01

    Analysis of structural, stratigraphic, and gravimetric data from the Reconcavo, Tucano, and Sergipe-Alagoas basins in northeastern Brazil and the Gabon basin in Africa shows that these basins originated in a double rifting system associated with multiple crustal detachment surfaces and that the direction of dip of the detachment surfaces was reversed at the Vaza-Barris fault system. This geometry is in agreement with models and data from modern rifts, but it requires the existence of a predominantly extensional stress regime in the northern part of the South Atlantic during the early stages of oceanic evolution. Evidence for the existence of such a stress regime is given by application of kinematic constraints to Early Cretaceous reconstructions of the South Atlantic Ocean. Interpretation of the regional geologic setting suggests that the double rifting system and the point of final continental rupture were controlled by the preexisting structural orientation of the tectonic provinces in the Precambrian basement.

  19. Tracking the source of mineralisation in the Tampere Basin (southern Finland), insights from structure, sedimentology and geophysics studies

    DEFF Research Database (Denmark)

    Moreau, Julien; Torvela, Taija; Kalliomäki, Henrik

    2013-01-01

    -(sulphides-)rich deposits occur. However most of the sulphides seems to be associated with an important tectonic structure. The structural study suggests that these sulphide-bearing horizons originally localised within relatively low-angle thrusts that later rotated into a subvertical orientation. The suggested model......The ancient basins are of a wide interest to geoscientists as they archive the early development of plate tectonics, life, and ore-bearing systems. Several basins, especially those involving volcanic-derived materials, contain ore and mineral deposits. The formation of these ores is often related...... implies that early gently dipping thrusts acted as both channels and traps for the mineralising fluids that possibly sourced from relatively shallow depths from the base of the basin infill. The origin of the fluids might therefore be either in relation with early metamorphosis of the sedimentary pile and...

  20. Thermal structure of the Panama Basin by analysis of seismic attenuation

    Science.gov (United States)

    Vargas, Carlos A.; Pulido, José E.; Hobbs, Richard W.

    2018-04-01

    Using recordings of earthquakes on Oceanic Bottom Seismographs and onshore stations on the coastal margins of Colombia, Panama, and Ecuador, we estimate attenuation parameters in the upper lithosphere of the Panama Basin. The tomographic images of the derived coda-Q values are correlated with estimates of Curie Point Depth and measured and theoretical heat flow. Our study reveals three tectonic domains where magmatic/hydrothermal activity or lateral variations of the lithologic composition in the upper lithosphere can account for the modeled thermal structure and the anelasticity. We find that the Costa Rica Ridge and the Panama Fracture Zone are significant tectonic features probably related to thermal anomalies detected in the study area. We interpret a large and deep intrinsic attenuation anomaly as related to the heat source at the Costa Rica Ridge and show how interactions with regional fault systems cause contrasting attenuation anomalies.

  1. Understanding the subsurface thermal structure of deep sedimentary basins in Denmark - measurements and modelling results

    DEFF Research Database (Denmark)

    Balling, N.; Poulsen, Søren Erbs; Bording, Thue Sylvester

    2015-01-01

    Most of the Danish area is characterized by deep sedimentary basins with a great potential for exploitation of geothermal energy. Geothermal reservoirs are present at various depths and temperatures. Currently, three geothermal plants are operating producing warm water for district heating purposes...... of different conductivity. Mean geothermal gradients from surface to depths of 1000 to 3000 m are generally between 20 and 35 °C/km. The subsurface thermal structure is clearly dominated by conduction. Advection by groundwater migration is generally insignificant. Heat flow increases significantly with depth...... due to perturbation from long-term palaeoclimatic surface temperature variations. Examples of modelled temperature distribution for selected geothermal reservoir are shown. In the Gassum Formation, which is present in most of the Danish area, temperatures are largely between 35 and 90 °C for depths...

  2. Basement membrane proteoglycans are of epithelial origin in rodent skin

    DEFF Research Database (Denmark)

    Yamane, Y; Yaoita, H; Couchman, J R

    1996-01-01

    . For in vivo experiments, pieces of newborn rat epidermis obtained by dispase treatment were grafted onto athymic nude mice. Three and six weeks after grafting, immunofluorescence analysis of the grafted skin was carried out, using monoclonal antibodies specific for rat basement membrane chondroitin sulfate...... on mice demonstrated the presence of rat basement membrane chondroitin sulfate proteoglycan and rat perlecan on interfollicular and follicular basement membranes including that separating dermal papillae from adjacent hair follicle epithelium. In contrast, the basement membranes of all dermal capillaries......-epidermal junction and hair follicle epithelium are of epidermal (epithelial) origin in vivo. Stratified rat keratinocytes cultured on a collagen matrix at the air-liquid interface showed the synthesis of perlecan, laminin 1, and type IV collagen in basement membranes, but not clearly detectable basement membrane...

  3. Study of the Ouarzazate basin structure by seismic reflection: hydrogeological implications

    Directory of Open Access Journals (Sweden)

    Jaffal, M.

    2009-12-01

    Full Text Available A large number of seismic reflection lines have been carried out in the Ouarzazate basin by the oil industry. The present study is concerned with the interpretation of a part of these data in order to characterize the structure of the Eocene aquifer system. The reflector corresponding to the base of this system, made up of sandstone and limestone, was first identified then digitized on each time-migrated seismic section. An isochrone map of this reflector was realized. The analysis of this map shows that the area under study is subdivided into two structurally contrasted domains. The first, the northern one, is intensively deformed; while the second, the southern one, is slightly folded. The results of this study provide a better understanding of the deep geological structure of the Ouarzazate basin. This allows us to better comprehend the functioning of the Eocene aquifer system, and to rationalize the future potential underground water exploration in the Ouarzazate basin.

    Les campagnes d’exploration pétrolière menées dans le bassin d’Ouarzazate ont permis l’acquisition d’une importante base de données de sismique réflexion. La présente étude concerne l’interprétation d’une partie de ces données dans l’objectif de caractériser la tectonique de l’Eocène et la structure de son système aquifère. Dans un premier temps, le réflecteur correspondant à la base de cet étage, représenté de grès et de calcaires, a été identifié, puis numérisé sur les différentes sections sismiques migrées-temps; ce qui nous a permis d’en établir une carte d’isochrones. Celle-ci montre que le secteur étudié est subdivisé en deux domaines très contrastés d’un point de vue structural. Le premier, septentrional, est affecté par une structuration intense de direction atlasique, tandis que le second, méridional, est faiblement plissé. Les résultats de la présente étude permettent une meilleure connaissance de la

  4. Seismic reflection surveys in central Palo Duro basin

    International Nuclear Information System (INIS)

    Acharya, H.; Buller, M.L.; Lewkowicz, J.; Murphy, P.

    1983-01-01

    Seismic reflection surveys have been conducted in the central Palo Duro basin to provide a basis for identifying localities suitable for the emplacement of an underground high level nuclear waste repository. The objectives of this effort were to determine the structure and stratigraphy in the central Palo Duro basin and evaluate the potential for hydrocarbon resources. Of primary interest is the Upper Permian salt section to a depth of about 3000 ft (914 m). Various tests were carried out along a 3 mi (5 km) segment to determine the most appropriate combination of vibrating source and recording parameters. Approximately 130 mi (209 km) of 24-fold CDP stacked data were acquired. The survey lines were tied to test wells in which velocity surveys were conducted. These data were supplemented by about 400 mi (644 km) of available proprietary CDP stacked data. Analysis of these data strongly suggests that central Palo Duro basin has been tectonically stable since Early Permian time. The maximum offset of the basement is about 600 ft (183 m). These basement faults do not appear to affect any strata above. The San Andres Formation and underlying formations can be traced continuously throughout the area surveyed. Available velocity data from various wells in the central Palo Duro basin show few anomalies, confirming the continuity of the reflecting horizons and the tectonic stability of the area. Hydrocarbon potential of the area is presently being evaluated. The preliminary results of this study are in agreement with the stratigraphic correlations among well logs in the Palo Duro basin

  5. STRUCTURE OF CONSORTIUM DESTRUCTIVE COMPONENTS IN THE INDUSTRIAL AREA OF KRIVYI RIG BASIN

    Directory of Open Access Journals (Sweden)

    V. V. Kachinskaya

    2014-07-01

    Full Text Available Тhe structural organization and a biological variety of ground mesofauna on consortium level of the organization of ecosystems are considered. The analysis of indicators of the structural organization and a biodiversity of ground mesofauna in consortium Ulmus and Populus in the conditions of territories of industrial mining – metallurgical complex of Krivyi Rig Basin is carried out. It is established that taxonomical structure of ground mesofauna is characterized by insignificant number and quantity of taxonomical groups. Prevalence in morfo-ecological structure of hortobiontes and herpetobiontes testifies about faunae considerable attachment to consortium determinants and influences of a steppe climate on its structure. Prevalence of phytophages and polyphages in trophic structure is caused by combination of determinants specificity of consortium and zone source of fauna formations. The structural organization of ground mesofauna in consortium Ulmus and Populus in the conditions of industrial sites is characterized simplified taxonomical structure with a low biodiversity at all levels. It was suggested that structural and functional organization of destructive components of the block consortium of Ulmus and Populus in the conditions of industrial sites are simplified and determined by biogeochemical patterns of pedogenic and leaf litter layer of consortium and type of anthropogenic impact. Management and sustainable use of consortium under technogenic pressure should be based on the effects of extreme and critical components in the evolution of consortium. These critical points are the type of leading man-made factors and pedogenic and leaf litter biogeochemical conditions of consortium determinants, which results in inhibition of development and simplification of the structural and functional organization of destructive components of the block. The elaboration of measures to restore and maintain that structural and functional organization

  6. Evolution of Meso-Cenozoic lithospheric thermal-rheological structure in the Jiyang sub-basin, Bohai Bay Basin, eastern North China Craton

    Science.gov (United States)

    Xu, Wei; Qiu, Nansheng; Wang, Ye; Chang, Jian

    2018-01-01

    The Meso-Cenozoic lithospheric thermal-rheological structure and lithospheric strength evolution of the Jiyang sub-basin were modeled using thermal history, crustal structure, and rheological parameter data. Results indicate that the thermal-rheological structure of the Jiyang sub-basin has exhibited obvious rheological stratification and changes over time. During the Early Mesozoic, the uppermost portion of the upper crust, middle crust, and the top part of the upper mantle had a thick brittle layer. During the early Early Cretaceous, the top of the middle crust's brittle layer thinned because of lithosphere thinning and temperature increase, and the uppermost portion of the upper mantle was almost occupied by a ductile layer. During the late Early Cretaceous, the brittle layer of the middle crust and the upper mantle changed to a ductile one. Then, the uppermost portion of the middle crust changed to a thin brittle layer in the late Cretaceous. During the early Paleogene, the thin brittle layer of the middle crust became even thinner and shallower under the condition of crustal extension. Currently, with the decrease in lithospheric temperature, the top of the upper crust, middle crust, and the uppermost portion of the upper mantle are of a brittle layer. The total lithospheric strength and the effective elastic thickness ( T e) in Meso-Cenozoic indicate that the Jiyang sub-basin experienced two weakened stages: during the late Early Cretaceous and the early Paleogene. The total lithospheric strength (approximately 4-5 × 1013 N m-1) and T e (approximately 50-60 km) during the Early Mesozoic was larger than that after the Late Jurassic (2-7 × 1012 N m-1 and 19-39 km, respectively). The results also reflect the subduction, and rollback of Pacific plate is the geodynamic mechanism of the destruction of the eastern North China Craton.

  7. Geochemistry of the Puna Austral and Cordillera Oriental basement

    International Nuclear Information System (INIS)

    Becchio, Raul; Lucassen, Friedrich; Franz, Gerhard; Kasemann, Simone

    1998-01-01

    Major and trace elements, rare earths, and 143 Nd/ 147 Nd and, 147 Sm/ 144 Nd isotope ratios have been determined in the Puna Austral and Cordillera Oriental basement. The basement is formed by high temperature amphibolite facies rocks ranulites (750-550 degrees C) and green schists. They are represented by schists, paragneiss, orthogneiss, migmatites, few metabasites, marbles and chalcosilicatic banks. Hypotheses on the formation and evolution of the basement are presented

  8. Basement membrane proteoglycans are of epithelial origin in rodent skin

    DEFF Research Database (Denmark)

    Yamane, Y; Yaoita, H; Couchman, J R

    1996-01-01

    proteoglycan and rat and mouse perlecan. While the isolated rat epidermis was shown to completely lack rat basement membrane chondroitin sulfate proteoglycan and rat basement membrane heparan sulfate proteoglycans, including perlecan, immunofluorescence staining of tissue sections from the grafted sites......-epidermal junction and hair follicle epithelium are of epidermal (epithelial) origin in vivo. Stratified rat keratinocytes cultured on a collagen matrix at the air-liquid interface showed the synthesis of perlecan, laminin 1, and type IV collagen in basement membranes, but not clearly detectable basement membrane...

  9. STRUCTURE OF CONSORTIUM DESTRUCTIVE COMPONENTS IN THE INDUSTRIAL AREA OF KRIVYI RIG BASIN

    Directory of Open Access Journals (Sweden)

    Kachinskaya V.V.

    2014-08-01

    Full Text Available Тhe structural organization and a biological variety of ground mesofauna on consortium level of the organization of ecosystems are considered. The analysis of indicators of the structural organization and a biodiversity of ground mesofauna in consortium Ulmus and Populus in the conditions of territories of industrial mining – metallurgical complex of Krivyi Rig Basin is carried out. It is established that taxonomical structure of ground mesofauna is characterized by insignificant number and quantity of taxonomical groups. Prevalence in morfo-ecological structure of hortobiontes and herpetobiontes testifies about faunae considerable attachment to consortium determinants and influences of a steppe climate on its structure. Prevalence of phytophages and polyphages in trophic structure is caused by combination of determinants specificity of consortium and zone source of fauna formations. The structural organization of ground mesofauna in consortium Ulmus and Populus in the conditions of industrial sites is characterized simplified taxonomical structure with a low biodiversity at all levels. It was suggested that structural and functional organization of destructive components of the block consortium of Ulmus and Populus in the conditions of industrial sites are simplified and determined by biogeochemical patterns of pedogenic and leaf litter layer of consortium and type of anthropogenic impact. Management and sustainable use of consortium under technogenic pressure should be based on the effects of extreme and critical components in the evolution of consortium. These critical points are the type of leading man-made factors and pedogenic and leaf litter biogeochemical conditions of consortium determinants, which results in inhibition of development and simplification of the structural and functional organization of destructive components of the block. The elaboration of measures to restore and maintain that structural and functional organization

  10. Active microbial community structure of deep subsurface sediments within Baltic Sea Basin

    Science.gov (United States)

    Reese, B. K.; Zinke, L.; Carvalho, G.; Lloyd, K. G.; Marshall, I.; Shumaker, A.; Amend, J.

    2014-12-01

    The Baltic Sea Basin (BSB) is a unique depositional setting that has experienced periods of glaciation and deglaciation as a result of climatic fluctuations over past tens of thousands of years. This has resulted in laminated sediments formed during periods with strong permanent salinity stratification. The high sedimentation rates make this an ideal setting to understand the microbial structure of a deep biosphere community in a relatively high carbon, and thus high-energy environment, compared to other deep subsurface sites. Samples were collected through scientific drilling during the International Ocean Discovery Program (IODP) Expedition 347 on board the Greatship Manisha, September-November 2013. We examined the active microbial community structure using the 16S rRNA gene transcript and active functional genes through metatranscriptome sequencing. Major biogeochemical shifts have been observed in response to the depositional history between the limnic, brackish, and marine phases. The active microbial community structure in the BSB is diverse and reflective of the unique changes in the geochemical profile. These data further refine our understanding of the existence life in the deep subsurface and the survival mechanisms required for this extreme environment.

  11. Seasonal Changes in Microbial Community Structure in Freshwater Stream Sediment in a North Carolina River Basin

    Directory of Open Access Journals (Sweden)

    John P. Bucci

    2014-01-01

    Full Text Available This study examined seasonal differences in microbial community structure in the sediment of three streams in North Carolina’s Neuse River Basin. Microbes that reside in sediment are at the base of the food chain and have a profound influence on the health of freshwater stream environments. Terminal-Restriction Fragment Length Polymorphism (T-RFLP, molecular fingerprint analysis of 16S rRNA genes was used to examine the diversity of bacterial species in stream sediment. Sediment was sampled in both wet and dry seasons from an agricultural (Bear, mixed urban (Crabtree and forested (Marks Creek, and the microbiota examined. Gamma, Alpha and Beta proteobacteria were prevalent species of microbial taxa represented among all sites. Actinobacteria was the next most prevalent species observed, with greater occurrence in dry compared to the wet season. Discernable clustering was observed of Marks and Bear Creek samples collected during the wetter period (September–April, which corresponded with a period of higher precipitation and cooler surface water temperatures. Although not statistically significant, microbial community structure appeared different between season (ANOSIM, R = 0.60; p < 0.10. Principal components analysis confirmed this pattern and showed that the bacterial groups were separated by wet and dry seasonal periods. These results suggest seasonal differences among the microbial community structure in sediment of freshwater streams and that these communities may respond to changes in precipitation during wetter periods.

  12. Evaporation Ponds or Recharge Structures ? the Role of Check Dams in Arkavathy River Basin, India

    Science.gov (United States)

    Jeremiah, K.; Srinivasan, V.; R, A.

    2014-12-01

    "Watershed development" has been the dominant paradigm for water management in India for the last two decades. Current spending on watershed development programmes rivals spending on large dams. In practice, watershed development involves a range of soil and water conservation measures including building check dams, gully plugs, contour bunds etc. Despite their dominance in water management paradigms, relatively little empirical data exists on these structures. Importantly, even though the benefits of individual watershed structures are recognized, the cumulative impact of building hundreds of such structures on hydrologic partitioning of a watershed remains unknown. We investigated the role of check dams in two small milli-watersheds in the Arkavathy River basin in South India. We conducted a comprehensive census of all check dams in the two milli-watersheds with a total area of 26 sq km. 40 check dams (representing a density of 1.35/sq km of watershed area) were geotagged, photographed, measured and their condition was recorded. We then selected twelve check dams and monitored the water stored using capacitance sensors. We also set up Automatic Weather Stations in each watershed. Inflows, evaporation and infiltration were calculated at each site to evaluate how check dams alter hydrologic partitioning in the watershed as a whole.

  13. Effects of radiation on the permeability of human basement membranes

    Science.gov (United States)

    Fan, B.-T.; Achour, S.; Simmonet, F.; Guerin, D.

    1999-02-01

    The influence of radiation on the permeability properties of human basement membrane was investigated by measuring the diffusion rate of several organic compounds (glycine, proline, glucose, urea and insulin) through human anterior lens capsules. The basement membranes borne an γ-irradiation treatment change significantly their permeability vis-a-vis studied organic substances. This modification in physico-chemical properties is probably due to the radiation, which alters or degrades the complex structure (or architecture) of basement membranes. Moreover the change in permeability is dependent upon the diffusing compounds. An increase in diffusion has been observed for glucose, glycine and urea. However for insulin and proline, a decrease in diffusion rate was observed. L'influence de radiation sur la perméabilité de la membrane basale a été étudiée par la mesure de la vitesse de diffusion de plusieurs composés organiques d'intérêt biologique (glycine, proline, glucose, urée et insuline) à travers la lame basale antérieure du cristallin de l'oil humain. Les membranes basales qui sont traitées avec l'irradiation γ changent significativement leur perméabilité vis-à-vis des substances organiques. Ce changement de propriétés physico-chimiques est probablement dû à l'altération ou la dégradation de la structure (ou de l'architecture) de la membrane basale entraînée par l'irradiation. De plus, la modification de la perméabilité de la membrane basale est dépendante des composés diffusants. Une augmentation de la vitesse de diffusion a été observée pour le glucose, le glycine et l'urée. Par contre, dans les cas de l'insuline et de la proline, on a observé une diminution de la vitesse de diffusion.

  14. Low Genetic Diversity and Structuring of the Arapaima (Osteoglossiformes, Arapaimidae Population of the Araguaia-Tocantins Basin

    Directory of Open Access Journals (Sweden)

    Carla A. Vitorino

    2017-10-01

    Full Text Available The arapaima, Arapaima gigas, is a fish whose populations are threatened by both overfishing and the ongoing destruction of its natural habitats. In the Amazon basin, varying levels of population structure have been found in A. gigas, although no data are available on the genetic diversity or structure of the populations found in the Araguaia-Tocantins basin, which has a topographic profile, hydrological regime, and history of fishing quite distinct from those of the Amazon. In this context, microsatellite markers were used to assess the genetic diversity and connectivity of five wild A. gigas populations in the Araguaia-Tocantins basin. The results of the analysis indicated low levels of genetic diversity in comparison with other A. gigas populations, studied in the Amazon basin. The AMOVA revealed that the Arapaima populations of the Araguaia-Tocantins basin are structured significantly. No correlation was found between pairwise FST values and the geographical distance among populations. The low level of genetic variability and the evidence of restricted gene flow may both be accounted for by overfishing, as well as the other human impacts that these populations have been exposed to over the years. The genetic fragility of these populations demands attention, given that future environmental changes (natural or otherwise may further reduce these indices and eventually endanger these populations. The results of this study emphasize the need to take the genetic differences among the study populations into account when planning management measures and conservation strategies for the arapaima stocks of the Araguaia-Tocantins basin.

  15. The Dead Sea Transform and the Dead Sea Basin - Structure and dynamics

    Science.gov (United States)

    Weber, M.; Desire Groups, D A

    2007-12-01

    DESERT and DESIRE, two multi-national, interdisciplinary research efforts by teams from Germany, Israel, Jordan and Palestine focused on the Dead Sea Transform (DST) and the Dead Sea Basin (DSB), respectively. The DST has accommodated left-lateral transform motion of 105 km between the African and Arabian plates since early Miocene (ca. 20 My), creating during this process also the prime example of a pull-apart basin, the DSB. Within DESERT the DST segment between the Dead Sea and the Red Sea called Arava/Araba Fault (AF) was studied with the following results. On plate tectonic scale the AF is a narrow, sub-vertical zone cutting through crust and lithosphere to more than 50 km depth, while the Moho depth increases smoothly from 26 km to 39 km from W to E under the DST. Several faults exist in the upper crust in a ca. 40 km wide zone around the AF, but none has kilometer-size zones of decreased seismic velocities/zones of high electrical conductivities typical for damage zones. Across the sub-vertical AF abrupt changes in lithology can be identified to a depth of 4 kilometers. The AF also acts as a barrier to fluids. The AF is the main active fault of the DST system but it has only accommodated a limited part (up to 60 km) of the overall 105 km of sinistral plate motion. Now inactive fault strands in the vicinity of the present day AF took up lateral motion until about 5 Ma ago, when the main, active fault trace shifted ca. 1 km westward to its present position. In the top few hundred meters of the AF a locally transpressional regime occurs in a 100 to 300 m wide zone of deformed and displaced material, bordered by sub-parallel faults forming positive flower structures. The damage zones of the individual faults are only 5 to 20 m wide. This narrow width is significantly smaller than at other major strike-slip faults of similar magnitude. Most of these findings are corroborated by thermo-mechanical modeling that show shear deformation in the lithosphere under the

  16. ENFORCEMENT OF FINANCIAL BASEMENTS AS A FACTOR OF TERRITORIES DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    E.N. Sidorova

    2007-06-01

    Full Text Available Article contains description of structure of regional finance resources, discloses the sources of financing, describes the role of budgeting. Problems and possible ways of solution of inter-budget relationships optimisation are described with the purpose of increasing of financial prosperity of territories. Overall role of optimisation as one of the most important factors of strengthening of financial basement of territories is described along with the necessity of considering the budget process as stimulated factor for regional economic systems development. Suggestions on substitution of cost method of budget resources management by the model of outcomes management and further development of mechanisms of territorial bodies interaction with economic entities on the base of state-private partnership were proposed.

  17. Hydrogeology of the Cliff House Sandstone in the San Juan structural basin, New Mexico, Colorado, Arizona and Utah

    Science.gov (United States)

    Thorn, Conde R.; Levings, G.W.; Craigg, S.D.; Dam, W.L.; Kernodle, J.M.

    1990-01-01

    This report is one in a series resulting from the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) study of the San Juan structural basin that began in October 1984. Previous reports in the series describe the hydrogeology of the Dakota Sandstone (Craigg and others, 1989), Point Lookout Sandstone (Craigg and others, 1990), Morrison Formation (Dam and others, 1990), Gallup Sandstone (Kernodle and others, 1989), and Menefee Formation (Levings and others, 1990) in the San Juan structural basin. The purposes of the RASA (Welder, 1986) are to: (1) Define and evaluate the aquifer system; (2) assess the effects of past, present, and potential ground-water use on aquifers and streams; and (3) determine the availability and quality of ground water. This report summarizes information on the geology and the occurrence and quality of water in the Cliff House Sandstone, one of the primary water-bearing units in the regional aquifer system. Data used in this report were collected during the study or were derived from existing records in the U.S. Geological Survey's computerized National Water Information System (NWIS) data base, the Petroleum Information Corporation's data base, and the Dwight's ENERGYDATA Inc. BRIN data base. Although all data available for the Cliff House Sandstone were considered in formulating the discussions in the text, not all those data could be plotted on the illustrations. The San Juan structural basin is in New Mexico, Colorado, Arizona, and Utah and has an area of about 21,600 square miles (fig. 1). The structural basin is about 140 miles wide and about 200 miles long. The study area is that part of the structural basin that contains rocks of Triassic or younger age and, therefore, is less extensive than the structural basin. Triassic through Tertiary sedimentary rocks are emphasized in this study because the major aquifers in the basin are present in these rocks. The study area is about 140 miles wide (about the same as the

  18. Shallow crustal structure of eastern-central Trans-Mexican Volcanic Belt.

    Science.gov (United States)

    Campos-Enriquez, J. O.; Ramón, V. M.; Lermo-Samaniego, J.

    2015-12-01

    Central-eastern Trans-Mexican Volcanic Belt (TMVB) is featured by large basins (i.e., Toluca, Mexico, Puebla-Tlaxcala, Libres-Oriental). It has been supposed that major crustal faults limit these basins. Sierra de Las Cruces range separates the Toluca and Mexico basins. The Sierra Nevada range separates Mexico basin from the Puebla-Tlaxcala basin. Based in gravity and seismic data we inferred the Toluca basin is constituted by the Ixtlahuaca sub-basin, to the north, and the Toluca sub-basin to the south, which are separated by a relative structural high. The Toluca depression is more symmetric and bounded by sub-vertical faults. In particular its eastern master fault controlled the emplacement of Sierra de Las Cruces range. Easternmost Acambay graben constitutes the northern and deepest part of the Ixtlahuaca depression. The Toluca-Ixtlahuaca basin is inside the Taxco-San Miguel de Allende fault system, and limited to the west by the Guerrero terrane which continues beneath the TMVB up to the Acambay graben. Mexico basin basement occupies an intermediate position and featured by a relative structural high to the north-east, as established by previous studies. This relative structural high is limited to the west by the north-south Mixhuca trough, while to the south it is bounded by the east-west Copilco-Xochimilco-Chalco sub-basin. The Puebla-Tlaxcala basin basement is the shallowest of these 3 tectonic depressions. In general, features (i.e., depth) and relationship between these basins, from west to east, are controlled by the regional behavior of the Sierra Madre Oriental fold and thrust belt basement (i.e., Oaxaca Complex?). This study indicates that an active east-west regional fault system limits to the south the TMVB (from the Nevado de Toluca volcano through the Popocatepetl volcano and eastward along southern Puebla-Tlaxcala basin). The Tenango and La Pera fault systems constituting the western part of this regional fault system coincide with northern

  19. Broadband Ground Motion Reconstruction for the Kanto Basin during the 1923 Kanto Earthquake

    Science.gov (United States)

    Sekiguchi, Haruko; Yoshimi, Masayuki

    2011-03-01

    Ground motions of the 1923 Kanto Earthquake inside the Kanto Basin are numerically simulated in a wide frequency range (0-10 Hz) based on new knowledge of the earthquake's source processes, the sedimentary structure of the basin, and techniques for generating broadband source models of great earthquakes. The Kanto Earthquake remains one of the most important exemplars for ground motion prediction in Japan due to its size, faulting geometry, and location beneath the densely populated Kanto sedimentary basin. We reconstruct a broadband source model of the 1923 Kanto Earthquake from inversion results by introducing small-scale heterogeneities. The corresponding ground motions are simulated using a hybrid technique comprising the following four calculations: (1) low-frequency ground motion of the engineering basement, modeled using a finite difference method; (2) high-frequency ground motion of the engineering basement, modeled using a stochastic Green's function method; (3) total ground motion of the engineering basement (i.e. 1 + 2); and (4) ground motion at the surface in response to the total basement ground motion. We employ a recently developed three-dimensional (3D) velocity structure model of the Kanto Basin that incorporates prospecting data, microtremor observations and measurements derived from strong ground motion records. Our calculations reveal peak ground velocities (PGV) exceeding 50 cm/s in the area above the fault plane: to the south, where the fault plane is shallowest, PGV reaches 150-200 cm/s at the engineering basement and 200-250 cm/s at the surface. Intensity 7, the maximum value in the Japan Meteorological Agency's intensity scale, is calculated to have occurred widely in Sagami Bay, which corresponds well with observed house-collapse rates due to the 1923 event. The modeling reveals a pronounced forward directivity effect for the area lying above the southern, shallow part of the fault plane. The high PGV and intensity seen above the

  20. Tectonic-stratigraphic evolution of mini-basins and salt provinces of Espirito Santo Basin-Brazil; Analise da evolucao tectono sedimentar de mini-bacias e provincias de sal da Bacia do Espirito Santo

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Neto, Walter Dias; Fernandes, Flavio Luis [Petroleum Geoscience Technology Ltda. (PGT), Rio de Janeiro, RJ (Brazil); Mohriak, Webster [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The Espirito Santo Basin integrates the group of basins along the eastern Brazilian continental margin. It is located between 18 deg and 21 deg S, encompassing an area of approximately 220,000 km{sup 2}, onshore and offshore the Espirito Santo State. Its geological limit with the Campos Basin to the south is defined by a Precambrian basement high (Vitoria Arch), and its northern limit with the Mucuri Basin is defined by a geopolitical limit. The study of salt tectonics processes in the Espirito Santo Basin allowed the deformational analysis and interpretation of the chronological evolution of the mini-basins developed between salt diapirs. We observe an intrinsic relationship between halokinesis and creation of subsidence troughs that may be important for trapping hydrocarbon reservoirs, and consequently form oil and gas accumulations in this portion of the basin. This geodynamics evolution of these structures is marked by a strong linkage between salt movement and coeval sedimentation in the interdomal basins, forming structures and stratigraphic traps that may constitute important aspects for the petroleum geology. (author)

  1. Effects of Flat Slab Subduction on Andean Thrust Kinematics and Foreland Basin Evolution in Western Argentina

    Science.gov (United States)

    Horton, B. K.; Fuentes, F.; McKenzie, N. R.; Constenius, K. N.; Alvarado, P. M.

    2014-12-01

    Debate persists over the effects of flat-slab subduction on the kinematics of overriding plate deformation and the evolution of retroarc sedimentary basins. In western Argentina, major spatial and temporal variations in the geometry of the subducting Nazca slab since ~15 Ma provide opportunities to evaluate the late Cenozoic response of the Andean fold-thrust belt and foreland basin to subhorizontal subduction. Preliminary results from several structural and sedimentary transects spanning the frontal thrust belt and foreland basin system between 31°S and 35°S reveal Oligocene-middle Miocene hinterland exhumation during normal-slab subduction followed thereafter by progressive slab shallowing with initial rapid cratonward propagation of ramp-flat thrust structures (prior to basement-involved foreland uplifts) and accompanying wholesale exhumation and recycling of the early Andean foreland basin (rather than regional dynamic subsidence). Detrital zircon U-Pb geochronologic data prove instrumental for revealing shifts in thrust-belt exhumation, defining depositional ages within the foreland basin, and constraining the timing of activity along frontal thrust structures. In both the San Juan (31-32°S) and Malargüe (34-35°S) segments of the fold-thrust belt, geochronological results for volcaniclastic sandstones and syndeformational growth strata are consistent with a major eastward advance in shortening at 12-9 Ma. This episode of rapid thrust propagation precedes the reported timing of Sierras Pampeanas basement-involved foreland uplifts and encompasses modern regions of both normal- and flat-slab subduction, suggesting that processes other than slab dip (such as inherited crustal architecture, critical wedge dynamics, and arc magmatism) are additional regulators of thrust-belt kinematics and foreland basin evolution.

  2. Geology, structure, and statistics of multi-ring basins on Mars

    Science.gov (United States)

    Schultz, Richard A.; Frey, Herbert V.

    1990-01-01

    Available data on Martian multi-ring basins were compiled and evaluated using the new 1:15 million scale geologic maps of Mars and global topography was revised as base maps. Published center coordinates and ring diameters of Martian basins were plotted by computer and superimposed onto the base maps. In many cases basin centers or ring diameters or both had to be adjusted to achieve a better fit to the revised maps. It was also found that additional basins can explain subcircular topographic lows as well as map patterns of old Noachian materials, volcanic plains units, and channels in the Tharsis region.

  3. Passive margins: U.S. Geological Survey Line 19 across the Georges Bank basin

    Science.gov (United States)

    Klitgord, Kim D.; Schlee, John S.; Grow, John A.; Bally, A.W.

    1987-01-01

    Georges Bank is a shallow part of the Atlantic continental shelf southeast of New England (Emery and Uchupi, 1972, 1984). This bank, however, is merely the upper surface of several sedimentary basins overlying a block-faulted basement of igneous and metamorphic crystalline rock. Sedimentary rock forms a seaward-thickening cover that has accumulated in one main depocenter and several ancillary depressions, adjacent to shallow basement platforms of paleozoic and older crystalline rock. Georges Bank basin contains a thickness of sedimentary rock greater than 10 km, whereas the basement platforms that flank the basin are areas of thin sediment accumulation (less than 5 km).

  4. Regional Rockburst Inidicator for Structural Units of Upper Silesia Coal Basin

    Science.gov (United States)

    Patyńska, Renata; Stec, Krystyna

    2017-09-01

    The paper presents the characteristics of seismic tremors and rockbursts that occurred between 2001 and 2015. The characteristics are based on a general description of the geological structure of the Upper Silesian Coal Basin (USCB). The level of seismic activity in the analysed period changed a number of times and depended on the intensity of mining works and diverse mining and geological conditions in each of the five regions where tremors occurred (Bytom Trough, Main Saddle, Main Trough, Kazimierz Trough, and Jejkowice and Chwałowice Troughs) and which belong to various structural units of the Upper Silesia. It was found out that in the case of rockbursts the phenomena were recorded in three regions. These are: Main Saddle, Bytom Trough, and Jejkowice and Chwałowice Troughs. The so called Regional Rockburst Indicator (RWT) was estimated for each of the regions where the rockbursts had been recorded. The obtained values of RWT are presented against the Probability of RockBurst (PT) in a given area.

  5. Statistical inference of seabed sound-speed structure in the Gulf of Oman Basin.

    Science.gov (United States)

    Sagers, Jason D; Knobles, David P

    2014-06-01

    Addressed is the statistical inference of the sound-speed depth profile of a thick soft seabed from broadband sound propagation data recorded in the Gulf of Oman Basin in 1977. The acoustic data are in the form of time series signals recorded on a sparse vertical line array and generated by explosive sources deployed along a 280 km track. The acoustic data offer a unique opportunity to study a deep-water bottom-limited thickly sedimented environment because of the large number of time series measurements, very low seabed attenuation, and auxiliary measurements. A maximum entropy method is employed to obtain a conditional posterior probability distribution (PPD) for the sound-speed ratio and the near-surface sound-speed gradient. The multiple data samples allow for a determination of the average error constraint value required to uniquely specify the PPD for each data sample. Two complicating features of the statistical inference study are addressed: (1) the need to develop an error function that can both utilize the measured multipath arrival structure and mitigate the effects of data errors and (2) the effect of small bathymetric slopes on the structure of the bottom interacting arrivals.

  6. Possible options for reducing occupational dose from the TMI-2 basement

    International Nuclear Information System (INIS)

    Munson, L.F.; Harty, R.

    1985-11-01

    The major sources of exposure in the basement include the enclosed stairwell/elevator shaft structure, water and sludge in the elevator shaft, cast concrete walls, concrete floor slab, water and sludge on the floor, and activity in the paint and loose surface contamination. The sources were identified using data obtained by the utility from water processing, water and solid samples, remote video inspections and radiation monitoring with a robot, and strings of thermoluminescent dosimeters lowered from upper elevations. The area dose rates in the basement range from approximately 4 R/hr (in the NE quadrant) to over 1100 R/hr (near the enclosed stairwell/elevator shaft structure). It is estimated that the basement contains between 11,000 and 21,000 curies of 137 Cs. Specific decontamination and cleanup techniques are discussed. These techniques include flushing with water, high-pressure water blasting, leaching, scabbling and chemical cleaning. The applicability of these techniques to the major sources of radiation are discussed, and possible approaches and work sequences for basement cleanup are given

  7. Investigation of the subsurface features of the basement complex of ...

    African Journals Online (AJOL)

    3D seismic reflection survey was recently carried out within the Zaria area of the basement complex of northern Nigeria, in order to investigate the complexity of the subsurface features within the basement. The geology of the survey area was characterized by gneisses and low grade meta-sedimentary rocks that form the ...

  8. Potential Development of Hydrocarbon in Basement Reservoirs In Indonesia

    Directory of Open Access Journals (Sweden)

    D. Sunarjanto

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i3.165Basement rocks, in particular igneous and metamorphic rocks are known to have porosity and permeability which should not be ignored. Primary porosity of basement rocks occurs as the result of rock formation. The porosity increases by the presence of cracks occurring as the result of tectonic processes (secondary porosity. Various efforts have been carried out to explore hydrocarbon in basement rocks. Some oil and gas fields proved that the basement rocks are as reservoirs which so far have provided oil and gas in significant amount. A review using previous research data, new data, and observation of igneous rocks in some fields has been done to see the development of exploration and basement reservoirs in Indonesia. A review on terminology of basement rock up till the identification of oil and gas exploration in basement rocks need to be based on the latest technology. An environmental approach is suggested to be applied as an alternative in analyzing the policy on oil and gas exploration development, especially in basement reservoirs.

  9. Basement and alluvial aquifers of Malawi: An overview of ...

    African Journals Online (AJOL)

    This paper highlights the quality of groundwater in basement and alluvial aquifers of Malawi through literature assessment. Groundwater in these aquifers serves about 60% of Malawian population. Alluvial aquifers yield high groundwater in excess of 10 L/s and more mineralized than basement aquifers. The values from ...

  10. Estimation of Magnetic Basement Depth of Oyo Area from ...

    African Journals Online (AJOL)

    The digitized magnetic intensity data of Oyo area, south western Nigeria was analyzed to estimate depths to magnetic sources as well as source locations. The total magnetic intensity values ranges from -143.8 nT to 147.0 nT suggesting contrasting rock types in the basement complex. The magnetic basement depth results ...

  11. Crustal structure and rift tectonics across the Cauvery–Palar basin ...

    Indian Academy of Sciences (India)

    The Cauvery–Palar basin is a major peri-cratonic rift basin located along the Eastern Continental Margin of India (ECMI) that had formed during the rift-drift events associated with the breakup of eastern Gondwanaland (mainly India–Sri Lanka–East Antarctica). In the present study, we carry out an integrated analysis of the ...

  12. Crustal structure and rift tectonics across the Cauvery–Palar basin ...

    Indian Academy of Sciences (India)

    ping and Curie point isothermal surface for geothermal reconnaissance; J. Geophys. Res. 80 4461–4465. Biswas S K, Bhasin A L and Jokhan Ram 1993 Classifi- cation of Indian sedimentary basins in the framework of plate tectonics; In: Proceedings of the second seminar on petroliferous basins of India: Dehradun (eds) ...

  13. Repository site definition in basalt: Pasco Basin, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Guzowski, R.V.; Nimick, F.B.; Muller, A.B.

    1982-03-01

    Discussion of the regional setting, geology, hydrology, and geochemistry of the Pasco Basin are included in this report. Pasco basin is a structural and topographic basin of approximately 2000 mi/sup 2/ (5180 km/sup 2/) located within the Yakima Fold Belt Subprovince of the Columbia Plateau. The stratigraphic sequence within the basin consists of an undetermined thickness of lower Miocene and younger flood basalts with interbedded and overlying sedimentary units. This sequence rests upon a basement of probably diverse rock types that may range in age from precambrian through early Tertiary. Although a large amount of information is available on the hydrology of the unconfined aquifer system, ground-water flow within the basin is, in general, poorly understood. Recharge areas for the Mabton interbed and the Saddle Mountains Formation are the highlands surrounding the basin with the flow for these units toward Gable Butte - Gable Mountain and Lake Wallula. Gable Butte - Gable Mountain probably is a ground-water sink, although the vertical flow direction in this zone is uncertain. The amount of upward vertical leakage from the Saddle Mountains Formation into the overlying sediments or to the Columbia River is unknown. Units underlying the Mabton interbed may have a flow scheme similar to those higher units or a flow scheme dominated by interbasin flow. Upward vertical leakage either throughout the basin, dominantly to the Columbia River, or dominantly to Lake Wallula has been proposed for the discharge of the lower units. None of these proposals is verified. The lateral and vertical distribution of major and minor ions in solution, Eh and pH, and ion exchange between basalt and ground-water are not well defined for the basin. Changes in the redox potential from the level of the subsurface facility to the higher stratigraphic levels along with the numerous other factors influencing K/sub d/, result in a poor understanding of the retardation process.

  14. Repository site definition in basalt: Pasco Basin, Washington

    International Nuclear Information System (INIS)

    Guzowski, R.V.; Nimick, F.B.; Muller, A.B.

    1982-03-01

    Discussion of the regional setting, geology, hydrology, and geochemistry of the Pasco Basin are included in this report. Pasco basin is a structural and topographic basin of approximately 2000 mi 2 (5180 km 2 ) located within the Yakima Fold Belt Subprovince of the Columbia Plateau. The stratigraphic sequence within the basin consists of an undetermined thickness of lower Miocene and younger flood basalts with interbedded and overlying sedimentary units. This sequence rests upon a basement of probably diverse rock types that may range in age from precambrian through early Tertiary. Although a large amount of information is available on the hydrology of the unconfined aquifer system, ground-water flow within the basin is, in general, poorly understood. Recharge areas for the Mabton interbed and the Saddle Mountains Formation are the highlands surrounding the basin with the flow for these units toward Gable Butte - Gable Mountain and Lake Wallula. Gable Butte - Gable Mountain probably is a ground-water sink, although the vertical flow direction in this zone is uncertain. The amount of upward vertical leakage from the Saddle Mountains Formation into the overlying sediments or to the Columbia River is unknown. Units underlying the Mabton interbed may have a flow scheme similar to those higher units or a flow scheme dominated by interbasin flow. Upward vertical leakage either throughout the basin, dominantly to the Columbia River, or dominantly to Lake Wallula has been proposed for the discharge of the lower units. None of these proposals is verified. The lateral and vertical distribution of major and minor ions in solution, Eh and pH, and ion exchange between basalt and ground-water are not well defined for the basin. Changes in the redox potential from the level of the subsurface facility to the higher stratigraphic levels along with the numerous other factors influencing K/sub d/, result in a poor understanding of the retardation process

  15. Interpretation of aeromagnetic data in the Jameson Land Basin, central East Greenland: Structures and related mineralized systems

    Science.gov (United States)

    Brethes, Anaïs; Guarnieri, Pierpaolo; Rasmussen, Thorkild Maack; Bauer, Tobias Erich

    2018-01-01

    This paper provides a detailed interpretation of several aeromagnetic datasets over the Jameson Land Basin in central East Greenland. The interpretation is based on texture and lineament analysis of magnetic data and derivatives of these, in combination with geological field observations. Numerous faults and Cenozoic intrusions were identified and a chronological interpretation of the events responsible for the magnetic features is proposed built on crosscutting relationships and correlated with absolute ages. Lineaments identified in enhanced magnetic data are compared with structures controlling the mineralized systems occurring in the area and form the basis for the interpretations presented in this paper. Several structures associated with base metal mineralization systems that were known at a local scale are here delineated at a larger scale; allowing the identification of areas displaying favorable geological settings for mineralization. This study demonstrates the usefulness of high-resolution airborne magnetic data for detailed structural interpretation and mineral exploration in geological contexts such as the Jameson Land Basin.

  16. Late Oligocene to present contractional structure in and around the Susitna basin, Alaska—Geophysical evidence and geological implications

    Science.gov (United States)

    Saltus, Richard W.; Stanley, Richard G.; Haeussler, Peter J.; Jones, James V.; Potter, Christopher J.; Lewis, Kristen A.

    2016-01-01

    The Cenozoic Susitna basin lies within an enigmatic lowland surrounded by the Central Alaska Range, Western Alaska Range (including the Tordrillo Mountains), and Talkeetna Mountains in south-central Alaska. Some previous interpretations show normal faults as the defining structures of the basin (e.g., Kirschner, 1994). However, analysis of new and existing geophysical data shows predominantly (Late Oligocene to present) thrust and reverse fault geometries in the region, as previously proposed by Hackett (1978). A key example is the Beluga Mountain fault where a 50-mGal gravity gradient, caused by the density transition from the igneous bedrock of Beluga Mountain to the >4-km-thick Cenozoic sedimentary section of Susitna basin, spans a horizontal distance of ∼40 km and straddles the topographic front. The location and shape of the gravity gradient preclude a normal fault geometry; instead, it is best explained by a southwest-dipping thrust fault, with its leading edge located several kilometers to the northeast of the mountain front, concealed beneath the shallow glacial and fluvial cover deposits. Similar contractional fault relationships are observed for other basin-bounding and regional faults as well. Contractional structures are consistent with a regional shortening strain field inferred from differential offsets on the Denali and Castle Mountain right-lateral strike-slip fault systems.

  17. Forest Composition and Structure Under Various Disturbance Regimes in the Alaknanda River Basin, Western Himalaya

    Directory of Open Access Journals (Sweden)

    Upma Manral

    2017-08-01

    Full Text Available This study explored the resilience of mountain forests in a protected area in Alaknanda River basin, Western Himalaya, to various disturbance scenarios. The resource dependency of village communities in the Kedarnath Wildlife Sanctuary Landscape was studied through a questionnaire survey in 10 villages situated along an elevational gradient. Vegetation sampling was done in government-owned sanctuary forests and community-owned forests, both visited by villagers. Forest community composition, regeneration status, and tree population structure were studied to understand the impact of disturbance on forests and their resistance to anthropogenic alterations. Results indicated a reduction in both fuelwood and fodder consumption with decreasing elevation, with villages at higher elevations and located inside the sanctuary depending more on forest resources. Forests showed evidence of disturbance in the form of lower basal cover, mean canopy cover, regeneration, and disturbance-influenced distribution of shrubs. However, despite the signs of secondary succession, Quercus leucotrichophora forest has retained the original tree species composition. Vegetation recovery on 3 landslide sites at varying successional stages was also studied. The old successional site had higher species richness than early successional sites. The only tree species with adult individuals recorded in early successional sites was Alnus nepalensis, an early successional nitrogen-fixing species. The community composition of the old successional site, at Bandwara, included young individuals of Q. leucotrichophora, the climax species of forests in that elevational range. The current forest structure of both disturbed forest and vegetation recovery on the old succession site indicate the resilient dynamism of native Himalayan forests. Considering the role of mountain forests in achieving sustainable development, it is imperative to study the dynamics of changes in forest community and

  18. The offshore basement of Perú: Evidence for different igneous and metamorphic domains in the forearc

    Science.gov (United States)

    Romero, Darwin; Valencia, Kiko; Alarcón, Pedro; Peña, Daniel; Ramos, Victor A.

    2013-03-01

    As a result of new studies carried out in the offshore of Perú during the exploration and hydrocarbon evaluation of the forearc basins, new U-Pb SHRIMP and TIMS in zircons and some Ar-Ar data were obtained in the metamorphic and igneous basement. The understanding of this basement was critical to evaluate different hypotheses that have been proposed for the tectonic evolution of pre-Andean crust of Perú. Recent research performed in the basement rocks of the Marañón Massif in northern Perú, claimed that west of this area was a basement-free region in the Paleozoic, where the arc and forearc were developed in a mafic quasi-oceanic crust. However, petrographic studies and new preliminary ages indicate, for the first time, the nature and age of this sialic basement. Reconnaissance studies were performed in several offshore islands, as the Las Hormigas de Afuera Island west of Lima, and Macabí and Lobera islands along the edge of the continental platform. These data were complemented with the studies of some cutting samples obtained in recent exploration wells in northern Perú. The results of the present work show two large crustal domains in the Peruvian offshore forearc. A northern domain contains late Paleozoic igneous rocks that appear to be the southern offshore continuation of the Amotape-Tahuin block, which is interpreted as the southernmost remnant of the Laurentia Alleghenian orogen. The central offshore domain, known as the Paracas High, corresponds to the outer shelf high of previous studies. It contains orthogneisses of Grenville-age, probably recrystallized during an Ordovician magmatic episode. The new results show that the central offshore of Perú is an extension of the Grenville-age basement affected by Famatinian, early Paleozoic magmatism, well exposed in the southern domain in the Arequipa Massif along the coast of southern Perú.

  19. The major basement membrane components localize to the chondrocyte pericellular matrix--a cartilage basement membrane equivalent?

    DEFF Research Database (Denmark)

    Kvist, Alexander J.; Nyström, Alexander; Hultenby, Kjell

    2007-01-01

    In this study, we demonstrate that articular cartilage chondrocytes are surrounded by the defining basement membrane proteins laminin, collagen type IV, nidogen and perlecan, and suggest that these form the functional equivalent of a basement membrane. We found by real-time PCR that mouse...... to the progression of degenerative joint disorders....

  20. Formation stage and controlling factors of the paleo-uplifts in the Tarim Basin: A further discussion

    Directory of Open Access Journals (Sweden)

    Yuan Neng

    2016-05-01

    Full Text Available Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin. Previously, there were multiple opinions on the pale-uplifts origins and structural evolution, so the oil and gas exploration ideas and deployment in the Tarim Basin were not developed smoothly. In this paper, regional seismic interpretation and structural analysis were carried out on the deep marine carbonate rocks in this basin based on the new seismic and drilling data. Then combined with the structural denudation results, the paleo-structural frameworks were reconstructed. And finally, the formation stage and main controlling factors of paleo-uplifts were discussed. It is shown that the Middle Ordovician is the key period when regional extension was converted to compression in this basin, so stratigraphic, sedimentary and structural differences occurred. Before the deposition of Yijianfang Fm in late Middle Ordovician, three carbonate paleo-uplifts (i.e., the Northern, Central and SW Tarim paleo-uplifts begun to appear, and they were all broad-folded paleo-uplifts of nearly E–W striking and were formed at the same stage. The distribution and development of the Phanerozoic uplifts in this basin are restricted by the Northern and Southern Tarim basement pale-uplifts of nearly E–W striking which were developed during the Precambrian. It is indicated that all the three paleo-uplifts are compressional paleo-uplifts originated from the convergence of the southern plate margin based on the basement paleo-uplifts and they are all characterized by similar structural characteristics and inherited formation and evolution. The current differences of paleo-uplifts are controlled by multi-stage intense structural reformation since the Silurian. It is concluded that the oil and gas exploration potential is immense in the carbonate reservoirs of well-preserved deep paleo-structural zones in a larger area.

  1. Spectral Depth Analysis of some Segments of the Bida Basin ...

    African Journals Online (AJOL)

    ADOWIE PERE

    2017-12-16

    Dec 16, 2017 ... ABSTRACT: Spectral depth analysis was carried out on ten (10) of the 2009 total magnetic field intensity data sheets covering some segments of the Bida basin, to determine the depth to magnetic basement within the basin. The data was obtained from the Nigerian Geological Survey Agency and used to ...

  2. FLORISTIC AND STRUCTURAL CHARACTERIZATION OF GALLERY FOREST FRAGMENTS OF UPPER ARAGUAIA RIVER BASIN

    Directory of Open Access Journals (Sweden)

    Christian Dias Cabacinha

    2014-06-01

    Full Text Available http://dx.doi.org/10.5902/1980509814575The forests of upper Araguaia river basin are daily exposed to degradation agents due to intense agriculture practices. Twenty two fragments (of 10 until 169 ha were surveyed according to point-centered quarter method to characterize vegetation structure and to create a database to forest restoration. One hundred and nine (109 species, belonging to 78 genus and 42 families, were sampled where 73.4% revealed zoochorous dispersal pattern, and 69.7% were classified to initial sucessional category. Shannon index and Pielou equability index were 3.86 nats. ind-1 and 0.82, respectively. Density and total basal area estimated were 1,351 trees.ha-1 and 19.28 m2.ha-1. The areas showed lower richness, Shannon and Pielou heterogeneity indices, lower basal area, and high number of species of intermediate stage of ecological sucession and colonization of cerrado and cerradão species in disturbed areas, altering the original landscape. Such situation, added to the importance of those areas for the biodiversity conservation and ecological services (mainly relative to the water, demands protection actions and management that use the great regenerative potential of the area, given by the existence of a great number of initial secondary species and the prevalence of zoochoric species.

  3. Avalonian crustal controls on basin evolution: implications for the Mesozoic basins of the southern North Sea

    Science.gov (United States)

    Smit, Jeroen; van Wees, Jan-Diederik; Cloetingh, Sierd

    2015-04-01

    Little is known of the Southern North Sea Basin's (SNSB) Pre-Permian basement due to a lack of outcrop and cores. The nature and structure of the East Avalonian crust and lithosphere remain even less constrained in the absence of deep seismic (refraction) lines. However, various studies have hinted at the importance of the Reactivation of the Early Carboniferous fault network during each consecutive Mesozoic and Cenozoic tectonic phase, demonstrating the key role of weak zones from the Early Carboniferous structural grain in partitioning of structural deformation and vertical basin motions at various scales. Although the older basin history and the basement attract increasing attention, the Pre-Permian tectonics of the SNSB remains little studied with most attention focused on the Permian and younger history. The strong dispersal of existing constraints requires a comprehensive study from Denmark to the UK, i.e. the East Avalonian microplate, bordered by the Variscan Rheïc suture, the Atlantic and Baltica. Based on an extensive literature study and the reinterpretation of publicly available data, linking constraints from the crust and mantle to stratigraphic-sedimentological information, we complement the map of Early Carboniferous rifting of East Avalonia and propose a new tectonic scenario. From the reinterpretation of the boundary between Avalonia and Baltica we propose a new outline for the Avalonian microplate with implications for the tectonics of the North German Basin. Furthermore, we highlight the nature and extent of the major crustal/lithospheric domains with contrasting structural behaviour and the major boundaries that separate them. Results shed light on the effects of long lived differences in crustal fabric that are responsible for spatial heterogeneity in stress and strain magnitudes and zonations of fracturing, burial history and temperature history. The geomechanical control of large crustal-scale fault structures will provide the constraints

  4. Crustal structure of an exhumed IntraCONtinental Sag (ICONS): the Mekele Basin in Northern Ethiopia.

    Science.gov (United States)

    Alemu, T. B.; Abdelsalam, M. G.

    2017-12-01

    The Mekele Sedimentary Basin (MSB) in Ethiopia is a Paleozoic-Mesozoic IntraCONtinental Sag (ICONS) exposed due to Cenozoic domal and rift flank uplift associated with the Afar mantle plume and Afar Depression (AD). ICONS are formed over stable lithosphere, and in contrast to rift and foreland basins, show circular-elliptical shape in map view, saucer shaped in cross section, and concentric gravity minima. Surface geological features of the MSB have been shown to exhibit geologic characteristics similar to those of other ICONS. We used the World Gravity Map (WGM 2012) data to investigate subsurface-crustal structure of the MSB. We also used 2D power spectrum analysis and inversion of the gravity field to estimate the Moho depth. Our results show the Bouguer anomalies of the WGM 2012 ranges between 130 mGal and - 110 mGal with the highest values within the AD. Despite the effect of the AD on the gravity anomalies, the MSB is characterized by the presence of gravity low anomaly that reaches in places -110 mGal, especially in its western part. The Moho depth estimates, from both spectral analysis and inversion of the gravity data, is between 36 and 40 km depth over most of the western and southern margins of the MSB. However, as the AD is approached, in the eastern margins of the MSB, crustal thickness estimates are highly affected by the anomalously thin and magmatic segment of the AD, and the Moho depth range between 30 and 25 km. Our results are consistent with that of seismic studies in areas far from the MSB, but within the Northwestern Ethiopian Plateau where the MSB is located. Those studies have reported an abrupt decrease in Moho depth from 40 km beneath the Northwestern plateau, to 20 km in the adjacent AD. Though the MSB is small (100 kmX100 km) compared to other ICONS, and affected by the neighboring AD, it is characterized by elliptical gravity minima and a relatively thicker crust that gradually thickens away from the rift. In addition, seismic imaging

  5. A seismic refraction study of the boundary between Bida basin and ...

    African Journals Online (AJOL)

    The average velocity of the second layer is 6100 ms-1, which indicates that the basement in the survey area consists of rocks mostly of granite schists, with other ... part, the thickness reduced to 2.3m indicating that the survey area lies over the boundary between the Zaria basement complex and the Bida sedimentary basin.

  6. Structural and depositional controls on the sedimentary fill of the Algoa Basin-South Africa, and its hydrocarbon potential

    Science.gov (United States)

    Al-Raisi, Muatasam Hassan

    The Algoa Basin, located on the southeastern margin of South Africa, is a Mesozoic rift basin covering an offshore area of 4000 square kilometers. This half graben is bounded by Recife arch and Port Alfred arch, and its offshore portion is composed of two sub basins, the Port Elizabeth and Uitenhage Troughs, initiated during the breakup of Gondwana in the Middle to Late Jurassic. The sediments filling the basin are divided into: Syrnift in the Oxfordian to Aptian (152 my to 113 my); Canyon fill in the Aptian to Albian (113 my to 103 my); and Thermal subsidence in the Albian (post 103 my). Using seismic data, well data, (including cuttings, cores, and log character), and Soekor (Pty) Ltd. completion reports, 24 unconformities and associated depositional sequences were recognized and correlated across the basin. The rift to drift transition in the offshore Algoa Basin was punctuated by the Aptian 13At1 (113 my) and the Albian 14At1 (103 my) unconformities. The Algoa canyon is incised into the 13At1 surface and filled from four feeder entry points by fluvial dominated deltas controlled by the tectonic fabric of the horsts and grabens. Higher amplitude/continuous reflectors at the base of prograding clinoforms correspond to the basinward turbidity systems. The 14At1 unconformity surface truncates the canyon fill and is a ubiquitous surface in the Outeniqua basin marking the boundary between pronounced changes in tectonic and sedimentary style that separate the rift to drift phases of extension. Future exploration of the basal canyon slope fans and/or prograding wedges sands should focus on the near west side of the Uitenhage fault and along the axis of the canyon fairways in the locally unfaulted Algoa canyon area. Structural analysis indicates the basin is dissected by a series of NW-SE trending faults. The faults may have induced hydrocarbon migration in the area. Rock-Eval pyrolysis analysis suggests that the Algoa Source rocks are less than 100 meters thick, and

  7. Electrical structures in the northwest margin of the Junggar basin: Implications for its late Paleozoic geodynamics

    Science.gov (United States)

    Zhang, Sheng; Xu, Yixian; Jiang, Li; Yang, Bo; Liu, Ying; Griffin, W. L.; Luo, Yong; Huang, Rong; Zhou, Yong; Zhang, Liangliang

    2017-10-01

    Recent geological, geochemical and geophysical data have inclined to support the presence of a remnant Paleozoic oceanic lithosphere beneath the Western Junggar, southwestern Chinese Altaids. However, regional high-resolution geophysical data have been rarely deployed to image its geometry, making it difficult to trace its evolution and final geodynamic setting. Presently, two magnetotelluric (MT) profiles are deployed across the northwest margin of the Junggar basin and the southern Darbut belt to image the electrical structure of the crust and lithospheric mantle. High-quality data at 102 sites and the quasi-2D indications of phase tensor skew angles and impedance phase ellipses for relatively short periods (up to 500 s) allow us to invert the two profile data by a 2-D scheme. The resistivity cross-section of a NW-SE striking LINE2 sheds light on a fossil intraoceanic subduction system, and reveals the Miaoergou intrusions as a bowl-like pluton, indicating that the multi-phase intrusions primarily formed in a post-collisional setting. The resistivity cross-section of striking NE-SW LINE1 reveals a possible oceanic slab with relatively lower resistivity underlying the low-resistivity sedimentary strata and high-resistivity mélange. Given that the profile of LINE1 cuts the out-rise zone of a subducted slab developed during the late Paleozoic, the 2-D resistivity model may thus represent the zone that have experienced heterogeneous deformation, reflecting subduction with barrier variation parallel to the ancient trench. Moreover, as shown in previous results, the new MT data also illustrate that the Darbut Fault is a thin-skinned structure, which has been erased at depths during the subsequent magmatism.

  8. A Synthesis of Paleo-Present Stress and Structural Evolution in the Western Anadarko Basin

    Science.gov (United States)

    Gragg, E.; van Wijk, J.

    2017-12-01

    This research uses a compilation of geological and geophysical data from literature and public databases paired with new seismic, petrophysical and core analyses to deduce the stress and structural histories of the western Anadarko Basin from 1.3 Ga to present day. Paleo-stress fields are vital to understand fold-faulting styles, fracture networks, and the evolution of stratigraphic mechanics through time. These are features that can drastically influence paleo-present fluid migration and accumulations in the subsurface. This work is conducted in an effort to characterize risks to commercial-scale geologic carbon storage via CO2 Enhanced Oil Recovery. We conducted palinspastic restorations on a field-scale fault system using a 3D seismic survey, and also used a fault database produced by the Oklahoma Geological Survey in the analysis. Preliminary results indicate that stress field reorganization occurred multiple times, and is related to a variety of orogenic and epeirogenic events. Sparse age data allow us to constrain at least four of these stress field phases: 1) Mid-Proterozoic crustal grain development; 2) Cambrian Southern Oklahoma Aulacogen; 3) Late Mississippian orogeny, and Pennsylvanian epeirogeny; and 4) Cenozoic Laramide convergence. Stress states influence faulting style and fracture development that can impact CO2 storage and production performance. Future work will explore anthropogenic effects of prior and future production on the stress states and structures at the field scale via the construction of a 3D mechanical earth model coupled to flow simulators. Funding for this project is provided by the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) through the Southwest Partnership on Carbon Sequestration (SWP) under Award No. DE-FC26-05NT42591.

  9. Characterization of lacustrine shale pore structure: The Upper-Triassic Yanchang Formation, Ordos Basin, China

    Directory of Open Access Journals (Sweden)

    Yuxi Yu

    2016-08-01

    Full Text Available Amounts of silty laminae in continental shale gas reservoir were investigated in the Zhangjiatan shale of the Yanchang Formation, Ordos Basin. The purpose of this study is to provide awareness in terms of the nature and discrepancies in pore structure between silty laminae and clayey laminae. By mechanically separating the silty laminae from the shale core, a combination measurement series of mercury injection capillary pressure, N2 adsorption, and carbon dioxide adsorption were performed on the aforementioned two parts. An integrated pore size distribution, with a pore diameter range of 0.1 nm-100 μm, was obtained by using appropriate sample particle size and calculation model. The comparative analysis of the pore structure shows that the clayey laminae are dominated by mesopore and micropore; meanwhile, the silty laminae are dominated by macropore alone. The pore volume distribution in clayey laminae is sorted as mesopore volume > micropore volume > macropore volume, on the other hand, for silty laminae it is macropore volume > mesopore volume > micropore volume. The averaged total pore volume of silty laminae is 2.02 cc/100 g, and for clayey laminae, it is 1.41 cc/100 g. The porosity of silty laminae is 5.40%, which is greater than that of clayey laminae's 3.67%. Since silty laminae have larger pore width and pore space, they are more permeable and porous than the clayey laminae; it also acts as a favorable conduit and reservoir for shale gas.

  10. Population structure of Bathymodiolus manusensis, a deep-sea hydrothermal vent-dependent mussel from Manus Basin, Papua New Guinea

    Directory of Open Access Journals (Sweden)

    Andrew D. Thaler

    2017-08-01

    Full Text Available Deep-sea hydrothermal vents in the western Pacific are increasingly being assessed for their potential mineral wealth. To anticipate the potential impacts on biodiversity and connectivity among populations at these vents, environmental baselines need to be established. Bathymodiolus manusensis is a deep-sea mussel found in close association with hydrothermal vents in Manus Basin, Papua New Guinea. Using multiple genetic markers (cytochrome C-oxidase subunit-1 sequencing and eight microsatellite markers, we examined population structure at two sites in Manus Basin separated by 40 km and near a potential mining prospect, where the species has not been observed. No population structure was detected in mussels sampled from these two sites. We also compared a subset of samples with B. manusensis from previous studies to infer broader population trends. The genetic diversity observed can be used as a baseline against which changes in genetic diversity within the population may be assessed following the proposed mining event.

  11. Structural setting of the Metán Basin (NW Argentina): new insights from 2D seismic profiles

    Science.gov (United States)

    Conti, Alessia; Maffucci, Roberta; Bigi, Sabina; Corrado, Sveva; Giordano, Guido; Viramonte, José G.

    2017-04-01

    The Metán Basin is located in the sub-Andean foreland, in the southernmost portion of the Santa Barbara system structural province (NW Argentina). The upper crust in this region shows a strong segmentation due to inherited stratigraphic and structural discontinuities, related to a Palaeozoic orogenic event and to a Cretaceous to Paleogene rifting event (Kley et al., 1999; Iaffa et al., 2011). This study seeks to unravel the deep structural setting of the basin, in order to better understand the tectonic evolution of the area. Different seismic sections are analysed, located in the Metán basin and acquired by YPF (Yacimientos Petrolíferos Fiscales, former national oil company of Argentina) in different surveys during the '70s - '80s. Stratigraphic control for the seismic interpretation is provided by petroleum exploratory wells drilled in the basin; they show a stratigraphic succession of syn-rift and post-rift deposits, mainly constituted by a continental succession of red beds, with minor limestone intercalations (Salta Group), overlain by a thick continental foreland basin succession (Orán Group) (Salfity et al., 1981). From a structural point of view, the Metán basin is characterized by a variety of structural trends, with thrust faults and related folds mainly trending N-S, NE-SW and NNE-SSW. Different mechanism can be responsible for the folding of the sedimentary cover; hangingwall anticlines are represented both by high angle thrust faults produced by inversion of Cretaceous extensional faults (Maffucci et al., 2015), and by fault propagation folds formed during the Andean shortening event. The study of the interaction between the older reactivated faults and the newly generated ones could provide new insights to unravel the complex structural setting of the area. References Iaffa D. N., Sàbat, F., Muñoz, J.A., Mon, R., Gutierrez, A.A., 2011. The role of inherited structures in a foreland basin evolution. The Metán Basin in NW Argentina. Journal of

  12. Glomerular basement membrane lipidosis in Alagille syndrome.

    Science.gov (United States)

    Davis, Jessica; Griffiths, Ryan; Larkin, Kay; Rozansky, David; Troxell, Megan

    2010-06-01

    Alagille syndrome is characterized by a paucity of interlobular bile ducts with chronic cholestasis, cardiac, skeletal, and eye abnormalities and is associated predominantly with JAG1 mutations. Various renal abnormalities have been sporadically described. The classic renal histopathology described in Alagille syndrome is mesangiolipidosis, with lipid deposits predominately confined to the mesangium and minimal deposition within the glomerular basement membrane (GBM). We report a 5-year-old girl with Alagille syndrome who presented with persistent subnephrotic proteinuria and renal tubular acidosis. A renal biopsy showed GBM irregularities (mimicking membranous glomerulonephritis), mesangial sclerosis, and focal segmental glomerulosclerosis (FSGS) on light microscopy. Electron microscopy revealed few lipid inclusions within the mesangium but extensive inclusions along the GBM. These findings are mostly consistent with those reported previously in Alagille syndrome. However, the histologic distribution of lipid vacuoles is seemingly reversed in this patient and is uniquely accompanied by FSGS, emphasizing the spectrum of renal histopathology seen in Alagille syndrome. The proteinuria observed in this patient is likely attributed to significant GBM lipid deposition, which over time may contribute to the development of FSGS.

  13. A Critical Review of the Oil and Tar Sands of the Dahomey Basin

    International Nuclear Information System (INIS)

    Osundina, A.; Mustapha, A.; Nzewi, T.

    2002-01-01

    The Benin Basin previously referred to as the Dahomey embayment has been designated as a frontier basin within Nigeria due to its potentially high prospects, but comparatively low exploitation campaign to date. The basin offers a promising opportunity for heavy oil exploration in a narrow belt extending westward from Edo State to the republic of Benin; while offshore, there are high prospects for finding more conventional hydrocarbon.The eastern Dahomey embayment is known to have an extensive reserve of hydrocarbons (bitumen and tar sands). The sediments occur in a 5 8 km belt stretching 120km from the fringes of Lagos State through Ogun, Ondo and Edo States. The estimated reserve potentials exceed 30 billion barrels of oil equivalent.Recently acquired seismic data in OPL 309 and 310, and subsequent drilling of 2 wells on the narrow continental shelf, have shown the presence of closed structures over Basement Highs and other related structural styles in the basin and confirm that conventional light oils and condensates hydrocarbons occur in commercial quantity. These hydrocarbons are reservoired in stratigraphic sequences of Albian Cenomanian age.This paper hopes to expose the hidden riches of this Basin and hopefully get the attention of the big players in refocusing their interests in the basin that attracted attention of the early petroleum explorers to Nigeria approximately 100 years ago

  14. Spectral depth analysis of some segments of the Bida Basin, Nigeria ...

    African Journals Online (AJOL)

    Spectral depth analysis of some segments of the Bida Basin, Nigeria, using aeromagnetic data. ... Journal of Applied Sciences and Environmental Management ... of the 2009 total magnetic field intensity data sheets covering some segments of the Bida basin, to determine the depth to magnetic basement within the basin.

  15. Revisiting the structure, age, and evolution of the Wharton Basin to better understand subduction under Indonesia.

    Digital Repository Service at National Institute of Oceanography (India)

    Jacob, J.; Dyment, J.; Yatheesh, V.

    Understanding the subduction processes along the Sunda Trench requires detailed constraints on the subducting lithosphere. We build a detailed tectonic map of the Wharton Basin based on reinterpretation of satellite-derived gravity anomalies...

  16. Engineering evaluation/cost analysis for disposal of structural concrete and soil from the 183-H Solar Evaporation Basin

    International Nuclear Information System (INIS)

    Badden, J.W.; Miller, L.R.

    1996-08-01

    This engineering evaluation/cost analysis is intended to aid the US Department of Energy, Richland Operations Office in selecting a preferred response action alternative for removing contaminated structural concrete and soils stockpiled next to the 183-H evaporation basin, which was conducted under the Resource Conservation and Recovery Act of 1976. This EE/CA evaluates possible alternative response actions and documents the decision making process

  17. Links between the structure of the mantle lithosphere and morphology of the Cheb Basin (Eger Rift, central Europe)

    Czech Academy of Sciences Publication Activity Database

    Babuška, Vladislav; Plomerová, Jaroslava; Vecsey, Luděk

    2010-01-01

    Roč. 99, č. 7 (2010), s. 1535-1544 ISSN 1437-3254 R&D Projects: GA ČR GA205/07/1088; GA AV ČR IAA300120709 Institutional research plan: CEZ:AV0Z30120515 Keywords : Western Bohemian Massif * Eger (Ohře) Rift * Cheb Basin * surface morphology * mantle lithosphere Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.980, year: 2010

  18. Assessing the geo-electric characteristics of Basement Complex rocks and its implication for groundwater prospecting in Ilorin Metropolis, Nigeria

    Directory of Open Access Journals (Sweden)

    I. P. Ifabiyi

    2016-12-01

    Full Text Available In Basement Complex rocks where rainfall is seasonal, water provision in dry season depends on regolith aquifer. For effective exploitation of groundwater resources, it is reasonable that geophysical investigation be conducted before development of well. In many instances, geophysical surveys may be expensive or nonexistent. Hence, there is a need for spatial analysis which might advise water engineers within such environments. Vertical Electrical Soundings (VES data of 53 locations conducted with ABEM SAS-1000 terrameter using Schlumberger electrode configuration were obtained from the hydrogeology Department of Kwara state Ministry of Water Resources and Lower Niger River Basin and Rural Development Authority, Ilorin. VES locational coordinates were recorded using handheld GPS device. Sound curves were evaluated by partial curve matching approach and computer iteration using WinResist. The results depict six geo-electric regional successions, namely: top soil, lateritic clay, weathered basement, fairly-hard basement, thin fractured and hard basement. The geo-electric succession identified was plotted in Surfer 12 environment, using kriging interpolation method to show spatial distribution pattern of this zone. The spatial pattern is expected to give an insight to the nature of spatial variability of geo-electric layers and assist drillers as well as water resources policy makers in their operations.

  19. Structural characteristics of an active fold-and-thrust system in the southeastern Atacama Basin, northern Chile

    Science.gov (United States)

    Lin, Yen-Sheng; Chuang, Yi-Rung; Shyu, J. Bruce H.; González, Gabriel; Shen, Chuan-Chou; Lo, Ching-Hua; Liou, Ya-Hsuan

    2016-08-01

    The western South American margin is one of the most active plate boundaries in the world. Using various remote sensing data sets, we mapped the neotectonic characteristics of an area at the southeastern corner of the Atacama Basin, northern Chile, in the Andean forearc. There, one major N-S trending ridge is clearly visible both in the satellite images and in the field. This ridge reaches 250 m above the basin floor in its middle part and is asymmetrical, with a steep eastern slope and a much gentler western slope. The geometry of the ridge indicates that it formed as an asymmetrical anticline. This anticline is likely formed as a shear fault-bend fold, with a major décollement at a depth of about 2.5 km in the Naranja Formation. We suggest that this décollement is a major structure of the Atacama Basin area. From the ages of the ignimbrites and lake deposits that were deformed by this anticline, we obtained a long-term shortening rate of the major underlying structure at about 0.2 mm/yr. This thin-skinned fold-and-thrust system appears to be active since at least about 3 Ma, and could be as long as since middle Miocene. Therefore, crustal structures may play important roles in the Neogene development of the western Andean margin.

  20. Structural evolution of the La Trocha fault zone: Oblique collision and strike-slip basins in the Cuban Orogen

    Science.gov (United States)

    Cruz-Orosa, Israel; Sã Bat, Francesc; Ramos, Emilio; Rivero, LluíS.; VáZquez-Taset, Yaniel M.

    2012-10-01

    The La Trocha fault zone acted as a major left-lateral transfer zone and is bounded by the La Trocha (LTF), Zaza-Tuinicú (ZTF), Cristales (CTF) and Taguasco (TGF) faults. These faults were consistent with the clockwise rotation of convergence and shortening in central Cuba. From the Paleocene to the Early Eocene (65-48 Ma), a SSW-NNE shortening produced transtension in the LTF and transpression in the ZTF. Subsequently, during the Middle Eocene (48-37 Ma), shortening shifted to a SW-NE direction, resulting in the normal component of the LTF and transpression in the ZTF and CTF. Since the Late Eocene (37 Ma), central Cuba has been welded to the North American Plate. The post-welding deformation gave rise to transtension of the LTF and TGF. This deformation is consistent with a WSW-ENE shortening and reflects activity in the transform boundary of the Cayman Trough. Both the normal and thrust displacements of these previous faults are corroborated by structural data whereas left-lateral displacement is deduced from the concordance between oblique collision and structural features. Plate-kinematics and the structural evolution of the La Trocha fault zone indicate that the related Central Basin is a strike-slip polygenetic basin and that the formation of this system (i.e., fault zone - strike-slip basin) was a consequence of the Paleogene oblique collision between the Caribbean Volcanic Arc and the Bahamas Borderland (North American plate).

  1. Structure and Stratigraphy of the Rift Basins in the Northern Gulf of California: Results from Analysis of Seismic Reflection and Borehole Data.

    Science.gov (United States)

    Martín, A.; González, M.; Helenes, J.; García, J.; Aragón, M.; Carreño, A.

    2008-12-01

    The northern Gulf of California contains two parallel, north-south trending rift basin systems separated by a basement-high. The interpretation of several exploration wells, and ~4500 km of seismic reflection data from PEMEX (Mexican national oil company) indicate that the tectonically active basins to the west (Wagner- Consag and Upper Delfin basins) may have initiated synchronously with the now abandoned Tiburón- Tepoca-Altar basins to the east in the Sonora margin. In both basin systems the lower sequence (A) is marine mudstone-siltstone, has parallel reflectors and a largely uniform thickness that reaches up to1.5 km, and gradually pinches out toward the lateral margins. This suggests that the unit was deposited prior to their segmentation by transtensional faulting. Marine microfossils from borehole samples from sequence A in the Tiburón and Consag basins indicates middle Miocene (>11.2 Ma) proto-Gulf conditions. Sequence B conformably overlies sequence A, and is characterized by up to 2 km growth strata with a fanning geometry that show a clear genetic relationship to the major transtensional faults that control the segmentation of the two basin systems. Sequence C in the Tiburón and Tepoca basins is comparatively thin (<800 m) and includes several unconformities, but is much less affected by faulting. In contrast, sequence C in the active Wagner, Consag and Upper Delfin basin is a much thicker (up to 2 km) growth sequence with abundant volcanic intrusions. Marked variations in sequence C in the different basin systems clearly demonstrate a major westward shift of deformation and subsidence at this time. The modern depocenter in Wagner-Consag basins is controlled by the Consag and Wagner faults, which trend parallel to the north ~20 km apart, and show opposite normal offset. These two faults merge at an oblique angle (70°-50°, respectively) into the Cerro Prieto transform fault to the north and likely accommodate an important amount of dextral shear. To

  2. Assessment of proteolytic degradation of the basement membrane: a fragment of type IV collagen as a biochemical marker for liver fibrosis

    DEFF Research Database (Denmark)

    Veidal, Sanne S.; Karsdal, Morten A.; Nawrocki, Arkadiusz

    2011-01-01

    Collagen deposition and an altered matrix metalloproteinase (MMP) expression profile are hallmarks of fibrosis. Type IV collagen is the most abundant structural basement membrane component of tissue, which increases 14-fold during fibrogenesis in the liver. Proteolytic degradation of collagens...

  3. Increasingly transformed MCF-10A cells have a progressively tumor-like phenotype in three-dimensional basement membrane culture.

    Science.gov (United States)

    Imbalzano, Karen M; Tatarkova, Iva; Imbalzano, Anthony N; Nickerson, Jeffrey A

    2009-03-16

    MCF-10A cells are near diploid and normal human mammary epithelial cells. In three-dimensional reconstituted basement membrane culture, they undergo a well-defined program of proliferation, differentiation, and growth arrest, forming acinar structures that recapitulate many aspects of mammary architecture in vivo. The pre-malignant MCF-10AT cells and malignant MCF-10CA1a lines were sequentially derived from the MCF-10A parental cell line first by expression of a constitutively active T24 H-Ras generating the MCF-10AT cell line. This was followed by repeated selection for increasingly aggressive tumor formation from cells recovered from xenograft tumors in immuno-compromised mice, generating the MCF-10CA1a cell line. When inoculated subcutaneously into the flanks of immuno-compromised mice, MCF-10AT cells occasionally form tumors, whereas MCF-10CA1a cells invariably form tumors with a shorter latency than MCF-10AT derived tumors. MCF-10AT cells grown in three-dimensional basement membrane culture form complex multi-acinar structures that produce a basement membrane but undergo delayed cell cycle arrest and have incomplete luminal development. MCF-10CA1a cells grown in three-dimensional basement membrane culture form large, hyper-proliferative masses, that retain few characteristics of MCF10A acini and more closely resemble tumors. Here we report on the growth and differentiation properties of these three matched cell lines in three-dimensional basement membrane culture. Features of tissue morphogenesis were assessed, including proliferation, basement membrane formation, polarization of alpha-6 beta-4 integrin to the basement membrane, formation of cell:cell junctions, and apoptosis for luminal clearance. The matched series of normal MCF-10A, pre-malignant MCF-10AT, and malignant MCF-10CA1a cells offers a unique opportunity to study the mechanisms of malignant progression both in a three-dimensional microenvironment and in the same cell background.

  4. An Interactive GIS Procedure for Building and Basement Corrections in Urban Microgravity Surveys

    Science.gov (United States)

    Chasseriau, P.; Olivier, R.

    2007-12-01

    Construction of a new underground railway in Lausanne, a highly-urbanized city in Switzerland, was an opportunity to test the feasibility and reliability of microgravity surveys in urban environments. The goal of our microgravity survey was to determine the depth-to-bedrock along the project corridor. Available drilling information allowed us verify the density model obtained. The geophysical results also provided spatially exhaustive subsurface information that could not be obtained with drilling methods alone. Gravimetry is one of the rare geophysical methods that can be used in noisy urban environments. An inevitable constraint of this method is terrain correction. It is not easy to obtain a simple and accurate digital elevation model (DEM) of an urban environment considering that buildings and basements are not included. However, these structures significantly influence gravity measurements. We calculate, with software that we have developed, the influence of buildings and basements in order to correct our gravity data. Our procedure permits the integration of gravity measurements, cadastral information (building typology and geometry) and basement geometry in an Access database that allows interactive determination of the Bouguer anomaly. A geographic information system (GIS) is used to extract building geometries based on cadastral information and to correct the influence of each building using a simplified architectural style. Basement voids are then introduced in the final DEM using building outlines given by cadastral maps. The depths and altitudes of the basements are measured by visiting them, and then linking the results to a regional topographic map. All of these corrections can be calculated before the gravity acquisition has begun in order to optimize the design of the survey. The surveys are executed late at night so as to minimize the effects of traffic noise. 160 gravity measurements were carried out before and after digging of the underground

  5. Tectono-sedimentary analysis using the anisotropy of magnetic susceptibility: a study of the terrestrial and freshwater Neogene of the Orava Basin

    Science.gov (United States)

    Łoziński, Maciej; Ziółkowski, Piotr; Wysocka, Anna

    2017-10-01

    The Orava Basin is an intramontane depression filled with presumably fine-grained sediments deposited in river, floodplain, swamp and lake settings. The basin infilling constitutes a crucial record of the neoalpine evolution of the Inner/Outer Carpathian boundary area since the Neogene, when the Jurassic-Paleogene basement became consolidated, uplifted and eroded. The combination of sedimentological and structural studies with anisotropy of magnetic susceptibility (AMS) measurements provided an effective tool for recognition of terrestrial environments and deformations of the basin infilling. The lithofacies-oriented sampling and statistical approach to the large dataset of AMS specimens were utilized to define 12 AMS facies based on anisotropy degree (P) and shape (T). The AMS facies allowed a distinction of sedimentary facies ambiguous for classical methods, especially floodplain and lacustrine sediments, as well as revealing their various vulnerabilities to tectonic modification of AMS. A spatial analysis of facies showed that tuffites along with lacustrine and swamp deposits were generally restricted to marginal and southern parts of the basin. Significant deformations were noticed at basin margins and within two intrabasinal tectonic zones, which indicated the tectonic activity of the Pieniny Klippen Belt after the Middle Miocene. The large southern area of the basin recorded consistent N-NE trending compression during basin inversion. This regional tectonic rearrangement resulted in a partial removal of the southernmost basin deposits and shaped the basin's present-day extent.

  6. Structural equation model of total phosphorus loads in the Red River of the North Basin, USA and Canada

    Science.gov (United States)

    Ryberg, Karen R.

    2017-01-01

    Attribution of the causes of trends in nutrient loading is often limited to correlation, qualitative reasoning, or references to the work of others. This paper represents efforts to improve causal attribution of water-quality changes. The Red River of the North basin provides a regional test case because of international interest in the reduction of total phosphorus loads and the availability of long-term total phosphorus data and ancillary geospatial data with the potential to explain changes in water quality over time. The objectives of the study are to investigate structural equation modeling methods for application to water-quality problems and to test causal hypotheses related to the drivers of total phosphorus loads over the period 1970 to 2012. Multiple working hypotheses that explain total phosphorus loads and methods for estimating missing ancillary data were developed, and water-quality related challenges to structural equation modeling (including skewed data and scaling issues) were addressed. The model indicates that increased precipitation in season 1 (November–February) or season 2 (March–June) would increase total phosphorus loads in the basin. The effect of agricultural practices on total phosphorus loads was significant, although the effect is about one-third of the effect of season 1 precipitation. The structural equation model representing loads at six sites in the basin shows that climate and agricultural practices explain almost 60% of the annual total phosphorus load in the Red River of the North basin. The modeling process and the unexplained variance highlight the need for better ancillary long-term data for causal assessments.

  7. A study of the distribution, structure and seismic stratigraphy of syn-breakup and post-breakup sediments in the Faroe sector of the Faroe-Shetland Basin

    DEFF Research Database (Denmark)

    Olavsdottir, Jana

    -activation of older, Mesozoic structural elements controlling the sediment path way and restricting the depositional areas. The structural elements being re-activated at different times causing considerable structural complexity. Understanding older, Mesozoic, structural elements control on sedimentation...... is a potential tool understanding deviations from “normal” thermal subsidence and for predicting the prospectivity in syn- and post-rift succession in the Faroe-Shetland Basin. On top of the basalt in the Faroe-Shetland Basin there is deposited up to 3.5 km thick sedimentary package, which led into the basin...... from different directions. With interpretations of 2-D and 3-D reflection seismic data of the post-basalt package it is shown which adjacent areas the various sub-sedimentary packages comes from and where they are located in the basin at specific time intervals. The adjacent areas to the Faroe...

  8. Sodium fire in the ILONA basement

    International Nuclear Information System (INIS)

    Klemm, H.

    1993-05-01

    The report describes the reasons, the course, the fire fighting measures and the consequences of the sodium fire, which damaged severely the 5 MW sodium test facility ILONA in Bergisch-Gladbach, Germany, in 1990. The accident occurred in the process of transferring Na from one tank containing 0.5 m''3 Na into another one with 6 m''3 Na, which were connected via sodium and gas exchange pipes. The 6 m''3 tank was also fitted with a dipping-pipe for the later purpose of filling or evacuation. The pipe was closed by a plug. The two tanks were flooded with argon. The leakage with consequent Na fire started during the preheating process of the 6 m''3 tank, and later investigations showed that Na had leaked from the dipping-pipe after a too high pressure built-up. Whether that happened because of the failure of a pressure compensation valve or because of a blockage of the pipe connecting the two tanks, could not be clarified after the accident because of the damages caused by the fire. The later analysis showed that about 4500 kg out of the originally 5820 kg had leaked from the tank during a time of about 5 hours. A total of 1344 kg Na were deposited as combustion product aerosols (carbonate and bi-carbonate) in the building and about 930 kg Na were released from the building to the atmosphere. On the basis of the temperature difference between 400 deg C in the basement and 20 deg C at the outlet and a height difference of 30 m, the gas stream was estimated to 4 m''3 per sec. The aerosol clouds left the building via the natural draught stack. They were quickly transformed into carbonate and bi-carbonate, which do not represent a risk for the people, the animals or the vegetation in the surroundings

  9. Genetic structure and historical diversification of catfish Brachyplatystoma platynemum (Siluriformes: Pimelodidae) in the Amazon basin with implications for its conservation

    Science.gov (United States)

    Ochoa, Luz Eneida; Pereira, Luiz Henrique G; Costa-Silva, Guilherme Jose; Roxo, Fábio F; Batista, Jacqueline S; Formiga, Kyara; Foresti, Fausto; Oliveira, Claudio

    2015-01-01

    Brachyplatystoma platynemum is a catfish species widely distributed in the Amazon basin. Despite being considered of little commercial interest, the decline in other fish populations has contributed to the increase in the catches of this species. The structure, population genetic variability, and evolutionary process that have driven the diversification of this species are presently unknown. Considering that, in order to better understand the genetic structure of this species, we analyzed individuals from seven locations of the Amazon basin using eight molecular markers: control region and cytochrome b mtDNA sequences, and a set of six nuclear microsatellite loci. The results show high levels of haplotype diversity and point to the occurrence of two structured populations (Amazon River and the Madeira River) with high values for FST. Divergence time estimates based on mtDNA indicated that these populations diverged about 1.0 Mya (0.2–2.5 Mya 95% HPD) using cytochrome b and 1.4 Mya (0.2–2.7 Mya 95% HPD) using control region. During that time, the influence of climate changes and hydrological events such as sea level oscillations and drainage isolation as a result of geological processes in the Pleistocene may have contributed to the current structure of B. platynemum populations, as well as of differences in water chemistry in Madeira River. The strong genetic structure and the time of genetic divergence estimated for the groups may indicate the existence of strong structure populations of B. platynemum in the Amazon basin. PMID:26045952

  10. Building America Top Innovations 2012: Basement Insulation Systems

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-01-01

    This Building America Top Innovations profile describes research on basement insulation, which identifies the wall installation methods and materials that perform best in terms of insulation and water resistance.

  11. Groundwater Exploration in the Basement Complex Around Chibok ...

    African Journals Online (AJOL)

    admin

    ABSTRACT: A geophysical survey employing Schlumberger electrode configuration using vertical electrical sounding (VES) method ... Keywords: Hydrogeology, Basement Complex, Alluvium, Colluviums, Electric resistivity, Chibok. INTRODUCTION .... unconcentrated surface runoff or sheet erosion. It is not concentrated ...

  12. Geology Structure Identification Using Pre-Stack Depth Migration (PSDM Method of Tomography Result in North West Java Basin

    Directory of Open Access Journals (Sweden)

    Sudra Irawan

    2017-06-01

    Full Text Available North West Java Basin is a tertiary sedimentary basin which is located in the right of the western part of the Java island. North West Java Basin is geodynamic where currently located at the rear position of the path of the volcanic arc of Java that is the result of the India-Australia plate subduction to the south towards the Eurasian plate (Explanation of Sunda in the north. Geology structure observation is difficult to be conducted at Quaternary volcanicfield due to the classical problem at tropical region. In the study interpretation of fault structures can be done on a cross-section of Pre-Stack Depth Migration (PSDM used prayer namely Hardware Key Device, ie Central Processing Unit: RedHat Enterprise Linux AS 5.0, prayer Monitor 24-inch pieces, Server: SGI altix 450/SuSe Linux Enterprise Server 9.0, 32 GB, 32 X 2,6 GHz Procesor, network: Gigabyte 1 Gb/s, and the software used is paradigm, product: Seismic Processing and Imaging. The third fault obtained in this study in accordance with the geological information derived from previous research conducted by geologists. The second general direction is northwest-southeast direction represented by Baribis fault, fault-fault in the Valley Cimandiri and Gunung Walat. This direction is often known as the directions Meratus (Meratus Trend. Meratus directions interpreted as directions that follow the pattern of continuous arc Cretaceous age to Meratus in Kalimantan.

  13. Paleostress Reconstruction from 3D seismic, Natural Fracture and Calcite Twin Analyses: Structural Insights into the Otway Basin, Australia

    Science.gov (United States)

    Burgin, Hugo; Amrouch, Khalid; Holford, Simon

    2017-04-01

    The Otway Basin, Australia, is of particular interest due to its significance as an Australian hydrocarbon producing province and a major global CO2 burial project. Structural data was collected in the form of natural fractures from wellbore image logs and outcrop in addition to calcite twin analyses, within formations from the mid cretaceous from both on and offshore. Evidence for four structural events within the study area have been identified including NE-SW and NW-SE orientated extension, in addition to a NW-SE compressive event. Natural fracture data also reveals a previously "un-detected" NE-SW compression within the Otway Basin. This study presents the first investigation of paleostress environments within the region from micro, meso and macro scale tectonic data in both onshore and offshore in addition to the first quantification of differential paleostresses. This work highlights the importance of a comprehensive understanding of four dimensional stress evolution within the sedimentary basins of Australia's southern margin.

  14. Associations among fish assemblage structure and environmental variables in Willamette Basin streams, Oregon

    Science.gov (United States)

    Waite, I.R.; Carpenter, K.D.

    2000-01-01

    As part of the U.S. Geological Survey's National Water-Quality Assessment Program, fish were collected from 24 selected stream sites in the Willamette Basin during 1993-1995 to determine the composition of the fish assemblages and their relation to the chemical and physical environment. Variance in fish relative abundance was greater among all sites than among spatially distinct reaches within a site (spatial variation) or among multiple sampled years at a site (temporal variation). Therefore, data from a single reach in an individual year was considered to be a reliable estimator of the fish assemblage structure at a site when the data were normalized by percent relative abundance. Multivariate classification and ordination were used to examine patterns in environmental variables and fish relative abundance over differing spatial scales (among versus within ecoregions). Across all ecoregions (all sites), fish assemblages were primarily structured along environmental gradients of water temperature and stream gradient (coldwater, high-gradient forested sites versus warmwater, low-gradient Willamette Valley sites); this pattern superseded patterns that were ecoregion specific. Water temperature, dissolved oxygen, and physical habitat (e.g., riparian canopy and percent riffles) were associated with patterns of fish assemblages across all ecoregions; however, pesticide and total phosphorus concentrations were more important than physical habitat within the Willamette Valley ecoregion. Consideration of stream site stratification (e.g., stream size, ecoregion, and stream gradient), identification of fish to species level (particularly the sculpin family), and detailed measurement of habitat, diurnal dissolved oxygen, and water temperature were critical in evaluating the composition of fish assemblages in relation to land use. In general, these low-gradient valley streams typical of other agricultural regions had poor riparian systems and showed increases in water

  15. The Rockall Trough, NE Atlantic: An Extinct Young Ocean Basin or a Failed Breakup Basin?

    Science.gov (United States)

    Roberts, Alan; Kusznir, Nick; Alvey, Andy

    2017-04-01

    We investigate the crustal structure and composition of the Rockall Trough which is located in the NE Atlantic to the west of Ireland and the UK. The Rockall Trough is a large extensional basin formed in the Early Cretaceous and has dimensions of approximately 250 km in width and 1000 km in length. It is one of several basins formed during the complex Mesozoic northward propagation of rifting, continental breakup and sea-floor spreading initiation of the North Atlantic; other adjacent basins formed at this time include the Porcupine Trough to its east and the East and West Orphan Basins on the Canadian conjugate margin. To investigate the crustal structure of the Rockall Trough we have used three independent analyses of available 2D and 3D data: 1. 3D gravity inversion, using public-domain gravity and sediment-thickness information, has produced maps of (i) depth to Moho, (ii) crustal thickness (figure 1) and (iii) stretching/thinning factor across both margins. 2. Gravity inversion as above, but using public-domain gravity data combined with new proprietary 2D sediment-thickness information, has produced a series of cross-sections which show (i) depth to Moho, (ii) crustal thickness and (iii) stretching/thinning factor across both margins 3. Geodynamic modelling, comprising 2D flexural backstripping and forward modelling, has been used to produce (i) estimates of stretching/thinning factor, (ii) whole-crustal cross-sections and (iii) predictions of palaeobathymetry through time along a series of project-specific transects. Our analysis of the Rockall Trough shows a rapid shallowing of crustal basement thicknesses on the flanks of the basin with central values of crustal thickness typically 8-10 km consistent with previously published seismic estimates. An important question is whether this thin crust is hyper-extended continental crust or proto-oceanic crust. Locally isolated patches of crustal thicknesses as low as 3km are observed which are consistent with the

  16. Tectonic Evolution of the Rift Basins in the Northeastern Brazilian Region

    Science.gov (United States)

    Mohriak, Webster U.; Bassetto, Marcelo; Vieira, Ines S.

    The transition from onshore failed rifts to offshore sedimentary basins along divergent continental margins is discussed on the basis of a regional, multidisciplinary integration of deep seismic reflection profiling, potential fied methods, geological data, and tectonic analysis. The following themes are addressed: a) the geologic evolution of the onshore and offshore rift systems of the Brazilian northeastern margin; b) the potential field methods response to the deep crustal structures; c) the seismic expression of major structural features in the rifts and within the continental and oceanic crusts; d) a possible geodynamic model for the evolution of the rift system; and e) analogies with a number of failed rifts and passive margin systems in the North Atlantic. The sedimentary basins in northeastern Brazil include a series of asymmetric grabens, such as the onshore Recôncavo-Tucano-Jatobá rift system (RTJ) and the offshore Jacuípe-Sergipe-Alagoas basins (JSA). Pre-rift sediments include Paleozoic to Jurassic/Early Cretaceous sediments deposited above a basement that includes Archean rocks to Late Proterozoic metasediments. The main rift phase (Neocomian to Barremian) terminated in the onshore rifts with fluvial deposits above a major regional unconformity. No further sedimentation is observed in the Recôncavo and Tucano basins, in a marked contrast to the geodynamic evolution of the Sergipe Basin, which is characterized by renewed phases of basement-involved faulting from Aptian to Early Albian, followed by a thermal phase of subsidence. The overall picture of two branches of a rift system, with different geodynamic evolution following the inception of oceanic crust, may be associated with a regional lithospheric extension during the Neocomian, first distributed over a wide region, and subsequently, focussing along a deeper mantle weak zone, local of a later plate rupture.

  17. Fault zone characteristics and basin complexity in the southern Salton Trough, California

    Science.gov (United States)

    Persaud, Patricia; Ma, Yiran; Stock, Joann M.; Hole, John A.; Fuis, Gary S.; Han, Liang

    2016-01-01

    Ongoing oblique slip at the Pacific–North America plate boundary in the Salton Trough produced the Imperial Valley (California, USA), a seismically active area with deformation distributed across a complex network of exposed and buried faults. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project to construct a three-dimensional P-wave velocity model down to 8 km depth and a velocity profile to 15 km depth, both at 1 km grid spacing. A VP = 5.65–5.85 km/s layer of possibly metamorphosed sediments within, and crystalline basement outside, the valley is locally as thick as 5 km, but is thickest and deepest in fault zones and near seismicity lineaments, suggesting a causative relationship between the low velocities and faulting. Both seismicity lineaments and surface faults control the structural architecture of the western part of the larger wedge-shaped basin, where two deep subbasins are located. We estimate basement depths, and show that high velocities at shallow depths and possible basement highs characterize the geothermal areas.

  18. Bedrock morphology and structure, upper Santa Cruz Basin, south-central Arizona, with transient electromagnetic survey data

    Science.gov (United States)

    Bultman, Mark W.; Page, William R.

    2016-10-31

    The upper Santa Cruz Basin is an important groundwater basin containing the regional aquifer for the city of Nogales, Arizona. This report provides data and interpretations of data aimed at better understanding the bedrock morphology and structure of the upper Santa Cruz Basin study area which encompasses the Rio Rico and Nogales 1:24,000-scale U.S. Geological Survey quadrangles. Data used in this report include the Arizona Aeromagnetic and Gravity Maps and Data referred to here as the 1996 Patagonia Aeromagnetic survey, Bouguer gravity anomaly data, and conductivity-depth transforms (CDTs) from the 1998 Santa Cruz transient electromagnetic survey (whose data are included in appendixes 1 and 2 of this report).Analyses based on magnetic gradients worked well to identify the range-front faults along the Mt. Benedict horst block, the location of possibly fault-controlled canyons to the west of Mt. Benedict, the edges of buried lava flows, and numerous other concealed faults and contacts. Applying the 1996 Patagonia aeromagnetic survey data using the horizontal gradient method produced results that were most closely correlated with the observed geology.The 1996 Patagonia aeromagnetic survey was used to estimate depth to bedrock in the upper Santa Cruz Basin study area. Three different depth estimation methods were applied to the data: Euler deconvolution, horizontal gradient magnitude, and analytic signal. The final depth to bedrock map was produced by choosing the maximum depth from each of the three methods at a given location and combining all maximum depths. In locations of rocks with a known reversed natural remanent magnetic field, gravity based depth estimates from Gettings and Houser (1997) were used.The depth to bedrock map was supported by modeling aeromagnetic anomaly data along six profiles. These cross sectional models demonstrated that by using the depth to bedrock map generated in this study, known and concealed faults, measured and estimated magnetic

  19. The Carboniferous to Jurassic evolution of the pre-Alpine basement of Crete: Constraints from U-Pb and U-(Th)-Pb dating of orthogneiss, fission-track dating of zircon, structural and petrological data

    Czech Academy of Sciences Publication Activity Database

    Romano, S. S.; Brix, M. R.; Dörr, K.; Fiala, Jiří; Krenn, E.; Zulauf, G.

    2006-01-01

    Roč. 260, - (2006), s. 69-90 ISSN 0375-6440 Institutional research plan: CEZ:AV0Z30130516 Keywords : tectonic-evolution * Carboniferous * Jurassic * uranium-lead-dating * orthogneiss * fission-track-dating * zircon * structural-geology * petrology * metamorphism * high-temperature Subject RIV: DB - Geology ; Mineralogy

  20. Analog modeling and kinematic restoration of inverted hangingwall synclinal basins developed above syn-kinematic salt: Application to the Lusitanian and Parentis basins

    Science.gov (United States)

    Roma, Maria; Vidal-Royo, Oskar; McClay, Ken; Ferrer, Oriol; Muñoz, Josep Anton

    2017-04-01

    The formation of hagingwall syncline basins is basically constrained by the geometry of the basement-involved fault, but also by salt distribution . The formation of such basins is common around the Iberian Peninsula (e.g. Lusitanian, Parentis, Basque-Cantabian, Cameros and Organyà basins) where Upper Triassic (Keuper) salt governed their polyphasic Mesozoic extension and their subsequent Alpine inversion. In this scenario, a precise interpretation of the sub-salt faults geometry and a reconstruction of the initial salt thickness are key to understand the kinematic evolution of such basins. Using an experimental approach (sandbox models) and these Mesozoic basins as natural analogues, the aim of this work is to: 1) investigate the main parameters that controlled the formation and evolution of hagingwall syncline basins analyzing the role of syn-kinematic salt during extension and subsequent inversion; and 2) quantify the deformation and salt mobilization based on restoration of analog model cross sections. The experimental results demonstrate that premature welds are developed by salt deflation with consequent upward propagation of the basal fault in salt-bearing rift systems with a large amount of extension,. In contrast, thicker salt inhibits the upward fault propagation, which results into a further salt migration and development of a hagingwall syncline basins flanked by salt walls. The inherited extensional architecture as well as salt continuity dramatically controlled subsequent inversion. Shortening initially produced the folding and the uplift of the synclinal basins. Minor reverse faults form as a consequence of overtightening of welded diapir stems. However, no trace of reverse faulting is found around diapirs stems, as ductile unit is still available for extrusion, squeezing and accommodation of shortening. Restoration of the sandbox models has demonstrated that this is a powerful tool to unravel the complex structures in the models and this may

  1. Crustal structure of the Western Carpathians and Pannonian Basin: Seismic models from CELEBRATION 2000 data and geological implications

    Science.gov (United States)

    Janik, Tomasz; Grad, Marek; Guterch, Aleksander; Vozár, Jozef; Bielik, Miroslav; Vozárova, Anna; Hegedűs, Endre; Kovács, Csaba Attila; Kovács, István; Keller, G. Randy; Celebration 2000 Working Group

    2011-08-01

    During the CELEBRATION 2000 seismic experiment, the Western Carpathians and Pannonian basin region was investigated by a dense system of deep seismic sounding profiles. In this paper, we present the results of modeling refracted and reflected waves employing 2D ray tracing for seven interlocking profiles that were jointly modeled and interpreted with the constraint that the models match at the crossing points of the profiles. The resulting P-wave velocity models reveal complex structures in the crust and large variations in the depth of the Moho discontinuity (˜25-45 km). In the southern part of the area, the relatively thin Pannonian basin crust consists of 3-7 km thick sediments and two crustal layers with velocities of 5.9-6.3 km/s in the upper crust and 6.3-6.6 km/s in the lower crust. In the central region, the upper crust of the ALCAPA (Alpine-Carpathian-Pannonian) microplate contains a high velocity body of Vp ≥ 6.4 km/s, which spatially corresponds with the Bükk Composite Terrane. The total thickness of the ALCAPA crust is 1-2 km greater than in the adjacent Tisza-Dacia microplate. To the north in the area of the Trans-European suture zone (TESZ) and Carpathian foredeep, we observe a 10-20 km thick upper crust with low velocity ( Vp ≤ 6.0 km/s). Sub-Moho velocities have average values of 7.8-8.0 km/s for the Pannonian basin, while in the Western Carpathians, the TESZ and the East European Craton (EEC) area, they are slightly higher (8.0-8.1 km/s). Lower velocities beneath the ALCAPA and Tisza-Dacia microplates could be caused by compositional variations and the significantly higher surface heat flow. Beneath some profiles, reflectors in the lithospheric mantle were found sub-parallel to the Moho but 10-20 km below it. Our integrated geophysical and geological analysis indicates that the observed structure was created by collision of two lithospheric plates with only a moderate degree of convergence. The northern plate consists of older European

  2. Evaluating upper versus lower crustal extension through structural reconstructions and subsidence analysis of basins adjacent to the D'Entrecasteaux Islands, eastern Papua New Guinea

    Science.gov (United States)

    Fitz, Guy; Mann, Paul

    2013-06-01

    The D'Entrecasteaux Island (DEI) gneiss domes are fault-bounded domes with ~2.5 km of relief exposing ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic gneisses and migmatites exhumed in an Oligocene-Miocene arc-continent collision and subduction zone subject to late Miocene to recent continental extension. Multichannel seismic reflection data and well data show the Trobriand basin formed as a fore-arc basin caused by southward Miocene subduction at the Trobriand trench. Subduction slowed at ~8 Ma as the margin transitioned to an extensional tectonic environment. Since then, the Trobriand basin has subsided 1-2.5 km as a broad sag basin with few normal faults deforming the basin fill. South of the DEI, the Goodenough rift basin developed after extension began (~8 Ma) as the hanging wall of the north-dipping Owen-Stanley normal fault that bounds the basin's southern margin. The lack of upper crustal extension accompanying subsidence in the Trobriand and Goodenough basins suggests depth-dependent lithospheric extension since 8 Ma has accompanied uplift of the DEI gneiss domes. Structural reconstructions of seismic profiles show 2.3-13.4 km of basin extension in the upper crust, while syn-rift basin subsidence values indicate at least 20.7-23.6 km of extension occurred in the entire crust since ~8 Ma. Results indicating thinning is preferentially accommodated in the lower crust surrounding the DEI are used to constrain a schematic model of uplift of the DEI domes involving vertical exhumation of buoyant, postorogenic lower crust, far-field extension from slab rollback, and an inverted two-layer crustal density structure.

  3. Frictional Behavior of Altered Basement Approaching the Nankai Trough

    Science.gov (United States)

    Saffer, D. M.; Ikari, M.; Rooney, T. O.; Marone, C.

    2017-12-01

    The frictional behavior of basement rocks plays an important role in subduction zone faulting and seismicity. This includes earthquakes seaward of the trench, large megathrust earthquakes where seamounts are subducting, or where the plate interface steps down to basement. In exhumed subduction zone rocks such as the Shimanto complex in Japan, slivers of basalt are entrained in mélange which is evidence of basement involvement in the fault system. Scientific drilling during the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) recovered basement rock from two reference sites (C0011 and C0012) located seaward of the trench offshore the Kii Peninsula during Integrated Ocean Discovery Program (IODP) Expeditions 322 and 333. The basement rocks are pillow basalts that appear to be heterogeneously altered, resulting in contrasting dense blue material and more vesicular gray material. Major element geochemistry shows differences in silica, calcium oxides and loss-on-ignition between the two types of samples. Minor element geochemistry reveals significant differences in vanadium, chromium, and barium. X-ray diffraction on a bulk sample powder representing an average composition shows a phyllosilicate content of 20%, most of which is expandable clays. We performed laboratory friction experiments in a biaxial testing apparatus as either intact sample blocks, or as gouge powders. We combine these experiments with measurements of Pennsylvania slate for comparison, including a mixed-lithology intact block experiment. Intact Nankai basement blocks exhibit a coefficient of sliding friction of 0.73; for Nankai basement powder, slate powder, slate blocks and slate-on-basement blocks the coefficient of sliding friction ranges from 0.44 to 0.57. At slip rates ranging from 3x10-8 to 3x10-4 m/s we observe predominantly velocity-strengthening frictional behavior, indicating a tendency for stable slip. At rates of < 1x10-6 m/s some velocity-weakening was observed, specifically in

  4. Basement Fault Reactivation by Fluid Injection into Sedimentary Reservoirs

    Science.gov (United States)

    Peter, Eichhubl; Fan, Zhiqiang; Zhu, Cheng

    2017-04-01

    Many suspected injection-induced earthquakes occur in crystalline basement rather than in the overlying sedimentary injection reservoir. To address why earthquakes nucleate in the basement rather than the injection layer we investigate the relationship between pore pressure diffusion, rock matrix deformation, and induced fault reactivation through 3D fully coupled poroelastic finite element models. These models simulate the temporal and spatial perturbation of pore pressure and solid stresses within a basement fault that extends into overlying sedimentary layers and that is conductive for flow along the fault but a barrier for flow across. We compare the effects of direct pore pressure communication and indirect poroelastic stress transfer from the injection reservoir to the fault on increasing the Coulomb failure stress that could reactivate the basement fault for normal, reverse, and strike-slip faulting stress regimes. Our numerical results demonstrate that volumetric expansion of the reservoir causes a bending of the fault near the injector and induces shear tractions along the downdip direction of the fault in the basement. These induced shear tractions act to increase the Coulomb failure stress for a normal faulting stress regime, and decrease the Coulomb failure stress for a reverse faulting regime. For a strike-slip faulting stress regime, the induced shear tractions increase the Coulomb failure stress both in the reservoir and basement. The induced normal traction on the fault reduces the Coulomb failure stress in all three tectonic regimes, but is larger in the reservoir than in the basement due to the more pronounced poroelastic effect in the reservoir. As a result, strike-slip stress regimes favor fault reactivation in the basement. Whereas the magnitude of the direct pore pressure increase exceeds the magnitude of induced poroelastic stress change, the poroelastic stress change increases the Coulomb failure stress in the basement fault for the normal

  5. Offshore structural trends from magnetic data over Cauvery Basin, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, A.S.; Lakshminarayana, S.; Chandrasekhar, D.V.; Murthy, K.S.R.; Rao, T.C.S.

    Detailed analysis of magentic and bathymetric data over shelf and slope regions of Cauvery Basin, east coast of India, between Mahabalipuram and Vedaranyam demarcated three major offshore lineaments trending N-S, NE-SW and E-W. The N-S lineation has...

  6. Phylogenetic signal and major ecological shifts in the ecomorphological structure of stream fish in two river basins in Brazil

    Directory of Open Access Journals (Sweden)

    Camilo Andrés Roa-Fuentes

    Full Text Available We tested the contribution of the phylogenetic and specific components to the ecomorphological structure of stream fish from the upper Paraguai River and upper São Francisco River basins, and identified nodes in the phylogenetic tree at which major ecological shifts occurred. Fish were sampled between June and October of 2008 in 12 streams (six in each basin. In total, 22 species from the upper Paraguai River basin and 12 from the upper São Francisco River were analyzed. The ecomorphological patterns exhibited phylogenetic signal, indicating that the ecomorphological similarity among species is associated with the degree of relatedness. A strong habitat template is most likely to be the primary cause for a high phylogenetic signal. A significant contribution from the specific component was also detected, supporting the idea that the phylogenetic signal occurs in some clades for some traits, but not in others. The major ecological shifts were observed in the basal nodes, suggesting that ecological niche differences appear to accumulate early in the evolutionary history of major clades. This finding reinforces the role of key traits in the diversification of Neotropical fishes. Ecological shifts in recent groups could be related to morphological modifications associated with habitat use.

  7. Immunochemical and autoantigenic properties of the globular domain of basement membrane collagen (type IV).

    Science.gov (United States)

    von der Mark, H; Oberbäumer, I; Timpl, R; Kemler, R; Wick, G

    1985-02-01

    Polyclonal rabbit antibodies raised against the globular domain NC1 of collagen IV from human placenta and a mouse tumor react with conformational antigenic determinants present on the NC1 hexamers and also with the three major subunits obtained after dissociation. The antibodies recognized unique structures within basement membranes and showed a broad tissue reactivity but only limited species cross-reactivity. Using these antibodies, it was possible to detect small amounts of collagen IV antigens from cell cultures and in serum. Monoclonal rat antibodies against mouse NC1 revealed a similar reaction potential. Autoantibodies could be produced in mice against mouse NC1 which react with kidney and lung basement membranes in a pathological manner, mimicking Goodpasture syndrome.

  8. Accelerating repaired basement membrane after bevacizumab treatment on alkali-burned mouse cornea

    Directory of Open Access Journals (Sweden)

    Koon-Ja Lee

    2013-04-01

    Full Text Available To understand the corneal regeneration induced by bevacizumab,we investigated the structure changes of stroma andbasement membrane regeneration. A Stick soaked in 0.5 NNaOH onto the mouse cornea and 2.5 mg/ml of bevacizumabwas delivered into an alkali-burned cornea (2 μl by subconjunctivalinjections at 1 hour and 4 days after injury. At 7 daysafter injury, basement membrane regeneration was observedby transmission electron microscope. Uneven and thin epithelialbasement membrane, light density of hemidesmosomes,and edematous collagen fibril bundles are shown in thealkali-burned cornea. Injured epithelial basement membraneand hemidesmosomes and edematous collagen fibril bundlesresulting from alkali-burned mouse cornea was repaired bybevacizumab treatment. This study demonstrates that bevacizumabcan play an important role in wound healing in thecornea by accelerating the reestablishment of basementmembrane integrity that leads to barriers for scar formation.[BMB Reports 2013; 46(4: 195-200

  9. The structure and stratigraphy of the sedimentary succession in the Swedish sector of the Baltic Basin: New insights from vintage 2D marine seismic data

    Science.gov (United States)

    Sopher, Daniel; Erlström, Mikael; Bell, Nicholas; Juhlin, Christopher

    2016-04-01

    We present five interpreted regional seismic profiles, describing the full sedimentary sequence across the Swedish sector of the Baltic Sea. The data for the study are part of an extensive and largely unpublished 2D seismic dataset acquired between 1970 and 1990 by the Swedish Oil Prospecting Company (OPAB). The Baltic Basin is an intracratonic basin located in northern Europe. Most of the Swedish sector of the basin constitutes the NW flank of a broad synclinal depression, the Baltic Basin. In the SW of the Swedish sector lies the Hanö Bay Basin, formed by subsidence associated with inversion of the Tornquist Zone during the Late Cretaceous. The geological history presented here is broadly consistent with previously published works. We observe an area between the Hanö Bay and the Baltic Basin where the Palaeozoic strata has been affected by transpression and subsequent inversion, associated with the Tornquist Zone during the late Carboniferous-Early Permian and Late Cretaceous, respectively. We propose that the Christiansø High was a structural low during the Late Jurassic, which was later inverted in the Late Cretaceous. We suggest that a fan shaped feature in the seismic data, adjacent to the Christiansø Fault within the Hanö Bay Basin, represents rapidly deposited, coarse-grained sediments eroded from the inverted Christiansø High during the Late Cretaceous. We identify a number of faults within the deeper part of the Baltic Basin, which we also interpret to be transpressional in nature, formed during the Caledonian Orogeny in the Late Silurian-Early Devonian. East of Gotland a number of sedimentary structures consisting of Silurian carbonate reefs and Ordovician carbonate mounds, as well as a large Quaternary glacial feature are observed. Finally, we use the seismic interpretation to infer the structural and stratigraphic history of the Baltic and Hanö Bay basins within the Swedish sector.

  10. Proterozoic crustal evolution of the Eucla basement, Australia: Implications for destruction of oceanic crust during emergence of Nuna

    Science.gov (United States)

    Kirkland, C. L.; Smithies, R. H.; Spaggiari, C. V.; Wingate, M. T. D.; Quentin de Gromard, R.; Clark, C.; Gardiner, N. J.; Belousova, E. A.

    2017-05-01

    The crystalline basement beneath the Cretaceous to Cenozoic Bight and Eucla Basins, in Western Australia has received comparatively little attention even though it lies on the eastern margin of one of the most mineral resource endowed regions on the planet. This basement is characterized by a complex geological evolution spanning c. 2 billion years, but paucity of outcrop and younger basin cover present a daunting challenge to understand the basement geology. In this work the composition of the unexposed Proterozoic crystalline basement to the Bight and Eucla Basins is investigated through zircon Hf isotopes and whole rock geochemistry from new drillcore samples. This region includes two geophysically defined basement entities: The Madura Province, containing: 1) c. 1478 Ma Sleeper Camp Formation, which has variable isotopic signatures including evolved values interpreted to reflect reworking of rare slivers of hyperextended Archean crust, 2) 1415-1389 Ma Haig Cave Supersuite, with mantle-like isotope values interpreted as melting of subduction-modified N-MORB source, and 3) 1181-1125 Ma Moodini Supersuite, with juvenile isotopic signatures interpreted to reflect mixed mafic lower-crustal and asthenospheric melts produced at the base of thinned crust. The Coompana Province, to the east of the Madura Province, has three major magmatic components: 1) c. 1610 Ma Toolgana Supersuite, with chemical and isotopic characteristics of primitive arc rock, 2) c. 1490 Ma Undawidgi Supersuite, with juvenile isotope values consistent with extensional processes involving asthenospheric input and 3) 1192-1140 Ma Moodini Supersuite, with strong isotopic similarity to Moodini Supersuite rocks in the Madura Province. This new isotopic and geochemical data shows that the Madura and Coompana regions together represent a huge tract of predominantly juvenile material. Magma sources recognised, include; 1) depleted mantle, producing MORB-like crust at c. 1950 Ma, but also contributing to

  11. Neogene deformation of thrust-top Rzeszów Basin (Outer Carpathians, Poland)

    Science.gov (United States)

    Uroda, Joanna

    2015-04-01

    The Rzeszów Basin is a 220 km2 basin located in the frontal part of Polish Outer Carpathians fold-and-thrust belt. Its sedimentary succession consist of ca. 600 m- thick Miocene evaporates, litoral and marine sediments. This basin developed between Babica-Kąkolówka anticline and frontal thrust of Carpathian Orogen. Rzeszów thrust-top basin is a part of Carpathian foreland basin system- wedge-top depozone. The sediments of wedge -top depozone were syntectonic deformed, what is valuable tool to understand kinematic history of the orogen. Analysis of field and 3D seismic reflection data showed the internal structure of the basin. Seismic data reveal the presence of fault-bend-folds in the basement of Rzeszów basin. The architecture of the basin - the presence of fault-releated folds - suggest that the sediments were deformed in last compressing phase of Carpathian Orogen deformation. Evolution of Rzeszów Basin is compared with Bonini et.al. (1999) model of thrust-top basin whose development is controlled by the kinematics of two competing thrust anticlines. Analysis of seismic and well data in Rzeszów basin suggest that growth sediments are thicker in south part of the basin. During the thrusting the passive rotation of the internal thrust had taken place, what influence the basin fill architecture and depocentre migration opposite to thrust propagation. Acknowledgments This study was supported by grant No 2012/07/N/ST10/03221 of the Polish National Centre of Science "Tectonic activity of the Skole Nappe based on analysis of changes in the vertical profile and depocentre migration of Neogene sediments in Rzeszów-Strzyżów area (Outer Carpathians)". Seismic data by courtesy of the Polish Gas and Oil Company. References Bonini M., Moratti G., Sani F., 1999, Evolution and depocentre migration in thrust-top basins: inferences from the Messinian Velona Basin (Northern Apennines, Italy), Tectonophysics 304, 95-108.

  12. Alterations of epithelial adhesion molecules and basement membrane components in lattice corneal dystrophy (LCD).

    Science.gov (United States)

    Resch, Miklós D; Schlötzer-Schrehardt, Ursula; Hofmann-Rummelt, Carmen; Kruse, Friedrich E; Seitz, Berthold

    2009-08-01

    amyloid were observed for collagen types IV, V, and XVIII, laminin alpha1, alpha3, and gamma1, nidogen-1 and -2, perlecan, fibrillin-1. Immunohistochemical and electron microscopic evidence of structural alterations was found in LCD compared to normal corneas concerning cell-matrix adhesion molecules and basement membrane components. These alterations were more pronounced in dystrophic corneas with subepithelial amyloid deposits than in those with stromal deposits. Histopathological findings may correspond to reduced cell-matrix interactions and partly explain delayed epithelial healing in patients with lattice corneal dystrophy.

  13. Structure of shumagin continental margin, Western Gulf of Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, T.R.; Von Huene, R.; Lewis, S.D.; Ladd, J.W.

    1985-04-01

    The Shumagin margin is characterized by five major structural features or trends: (1) Shumagin basin, containing about 2.5 km of late Miocene and younger strata above acoustic basement; (2) Sanak basin, containing as much as 8 km of dominantly late Cenozoic strata in two subbasins separated by a basement high; (3) cenozoic shelf-edge and upper-slope sedimentary wedges that are 3-4 km thick and possibly as thick as 6 km; (4) a midslope structural trend, Unimak ridge, that is characterized by numerous surface and subsurface structural highs; and (5) a 30-km wide accretionary complex at the base of the slope. A thin (less than 1-2 km) sediment cover of Miocene and younger age covers the continental shelf areas outside of Shumagin and Sanak basins. The tectonic history of the margin includes: (1)j late Cretaceous or early Tertiary removal of the seaward part of the Cretaceous Alaska Peninsula margin along the Border Ranges fault and accretion of the Shumagin Formation against the truncated margin; (2) Miocene uplift and erosion of the shelf; (3) middle or late Miocene uplift of Unimak ridge; and (4) late Miocene and younger subsidence and infilling of Sanak and Shumagin basins, and subduction-accretion along the Aleutian Trench.

  14. Monocline formation during growth of segmented faults in the Taranaki Basin, offshore New Zealand

    Science.gov (United States)

    Conneally, John; Childs, Conrad; Nicol, Andrew

    2017-11-01

    Precursor monoclines or fault propagation folds are commonly associated with normal faults. Many previous studies have analysed these structures at outcrop or in analogue models but there are few natural examples which have been studied in detail in 3D. Here we present the results of analysis of two monoclines imaged in a 3D seismic reflection survey in the Taranaki Basin, offshore New Zealand. The monoclines formed in response to Miocene-Recent extensional reactivation of underlying basement normal faults of Cretaceous age. The Miocene structures have associated growth strata that allows their geometrical evolution to be established. The two monoclines initiated at the same time ( 3.4 Ma). The smaller of the two monoclines has only limited associated faulting while the larger structure was cross-cut by upward propagation of the basement fault as a segmented array of normal faults. Variations in fold amplitudes and fault displacements within the growth strata associated with the larger structure record the progressive transition from folding to faulting, with folding limited to the relay zones between fault segments in the later stages of growth. This structure demonstrates spatial and temporal complementary relationships between folding and faulting so that together they define a single kinematically coherent structure. Although the monoclines widen upwards with geometries consistent with the trishear model of forced folding, there is also a positive correlation between monocline amplitude and wavelength measured along the length of the structure which suggests that the wavelengths of these structures increased as they grew.

  15. Magmatism in the brazilian sedimentary basins and the petroleum geology; Magmatismo nas bacias sedimentares brasileiras e sua influencia na geologia do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Thomaz Filho, Antonio; Antonioli, Luzia [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Faculdade de Geologia]. E-mails: antoniothomaz@globo.com; antonioli@novanet.com.br; Mizusaki, Ana Maria Pimentel [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias]. E-mail: ana.mizusaki@ufrgs.br

    2008-06-15

    In the recent years, the researches on the magmatic events that occurred in the Brazilian sedimentary basins had shown the importance of these episodes for the hydrocarbons exploration. The generation (heating), migration (structural and petrographic alterations), accumulation (basalt fractures) and migrations barriers (sills and dykes) of the hydrocarbons, produced for these rocks, are cited in the marginal and intra continental Brazilian basins. The magmatism produce the temperature increase in the sedimentary basin, around its intrusion, and this propitiate the maturation of the organic matter contained in the hydrocarbons generating rocks of the basin. At the same time, has been verified that the contacts dykes/sedimentary rocks can represent important ways for the hydrocarbons migrations. Recent studies have shown that the magmatism, in its extrusive manifestations, can be analyzed in view of the possibility of having acted as effective hydrocarbon seals and, in consequence, making possible the accumulation of hydrocarbons generated in the underlying sediments. The magmatism of predominantly basic to intermediary character is generated in the asthenosphere, that is, below the lithosphere. The dykes that had introduced in the basement of our sedimentary basins are good heat conductors and we can expect the geothermal gradients increase in the overlapped sedimentary deposits. The more detailed study of the magmatic processes in the Brazilian sedimentary basins must lead to new forms of hydrocarbons exploration in our sedimentary basins, also in those basins where the traditional exploration activities have not occasioned the waited expected successes. (author)

  16. Crustal structure of the Siberian craton and the West Siberian basin: An appraisal of existing seismic data

    DEFF Research Database (Denmark)

    Cherepanova, Yulia; Artemieva, Irina M.; Thybo, Hans

    2013-01-01

    We present a digital model SibCrust of the crustal structure of the Siberian craton (SC) and the West Siberian basin (WSB), based on all seismic profiles published since 1960 and sampled with a nominal interval of 50 km. Data quality is assessed and quantitatively assigned to each profile based...... on acquisition and interpretation method and completeness of crustal model. The database represents major improvement in coverage and resolution and includes depth to Moho, thickness and average P-wave velocity of five crustal layers (sediments, and upper, middle, lower, and lowermost crust) and Pn velocity...

  17. Paleoenvironmental reconstruction and evolution of an Upper Cretaceous lacustrine-fluvial-deltaic sequence in the Parecis Basin, Brazil

    Science.gov (United States)

    Rubert, Rogerio R.; Mizusaki, Ana Maria Pimentel; Martinelli, Agustín G.; Urban, Camile

    2017-12-01

    The Cretaceous in the Brazilian Platform records events of magmatism, tectonism and sedimentation coupled to the Gondwana breakup. Some of these events are registered as sedimentary sequences in interior basins, such as in the Cretaceous sequence of the Alto Xingu Sub-basin, Parecis Basin, Central Brazil. This article proposes the faciologic characterization and paleoenvironmental reconstruction of the Cretaceous sequence of the eastern portion of the Parecis Basin and its relation with some reactivated structures as, for instance, the Serra Formosa Arch. Based on both data from outcrops and core drillings a paleoenvironmental and evolutionary reconstruction of the sequence is herein presented. The base of the studied section is characterized by chemical and low energy clastic sedimentation of Lake Bottom and Shoreline, in a context of fast initial subsidence and low sedimentation rate. As the subsidence process decreased, a deltaic progradation became dominant with deposition in a prodelta environment, followed by a deltaic front and deltaic plain interbedded with fluvial plain, and aeolian deposition completing the sequence. The inferred Coniacian-Santonian age is based on vertebrate (fishes and notosuchians) and ostracod fossils with regional chrono-correlates in the Adamantina (Bauru Group), Capacete (Sanfranciscana Basin), and Bajo de la Carpa (Neuquén Group, in Argentina) formations. The formation of a Coniacian depocenter in the Alto Xingu Sub-basin is associated to the Turonian-Coniacian reactivation event in the Peruvian Orogenic Phase of the Andean Orogeny, with the transference of stresses to interplate setting, reactivating Proterozoic structures of the basement.

  18. Stratigraphic and structural relationships between Meso-Cenozoic Lagonegro basin and coeval carbonate platforms in southern Apennines, Italy

    Science.gov (United States)

    Pescatore, Tullio; Renda, Pietro; Schiattarella, Marcello; Tramutoli, Mariano

    1999-12-01

    Stratigraphic studies and facies analysis integrated with a new geological and structural survey of the Meso-Cenozoic units outcropping in the Campania-Lucania Apennines, southern Italy, allowed us to restore the palaeogeographic pattern and the tectonic evolution of the chain during Oligo-Miocene times. The southern Apennines are a N150°-striking and NE-verging fold-and-thrust belt mainly derived from the deformation of the African-Apulian passive margin. Four wide belts with different features have been recognized in the chain area. From east to west the following units outcrop: (a) successions characterized by basinal to marginal facies, ranging in age from Cretaceous to Miocene, tectonically lying on Plio-Pleistocene foredeep deposits; (b) successions characterized by shallow-water, basinal and shelf-margin facies, ranging in age from middle Triassic to Miocene ('Lagonegro units'), overthrust on the previous ones; (c) Triassic to Miocene carbonate platform successions ('Apenninic platform units'), overthrust on the Lagonegro units; (d) Jurassic-Cretaceous to Miocene deep-water successions (ophiolite-bearing or 'internal' units and associated siliciclastic wedges), outcropping along the Tyrrhenian belt and the Calabria-Lucania boundary, overthrust on the Apenninic platform units. All these units tectonically lie on the buried Apulian platform which is covered, at least in the eastern sector of the chain, by Pliocene to Pleistocene foredeep deposits. Stratigraphic patterns of the Cretaceous to lower Miocene Lagonegro successions are coherent with the platform margin ones. Calcareous clastics of the Lagonegro basin are in fact supplied by an adjacent western platform, as inferred by several sedimentological evidences (slump and palaeocurrent directions and decreasing grain size towards the depocentre of the basin). Tectonic relationships among the different units of the chain — with particular emphasis on the Lagonegro and Apenninic platform units of the

  19. Unconformity structures controlling stratigraphic reservoirs in the north-west margin of Junggar basin, North-west China

    Science.gov (United States)

    Wu, Kongyou; Paton, Douglas; Zha, Ming

    2013-03-01

    Tectonic movements formed several unconformities in the north-west margin of the Junggar basin. Based on data of outcrop, core, and samples, the unconformity is a structural body whose formation associates with weathering, leaching, and onlap. At the same time, the structural body may be divided into three layers, including upper layer, mid layer, and lower layer. The upper layer with good primary porosity serves as the hydrocarbon migration system, and also accumulates the hydrocarbon. The mid layer with compactness and ductility can play a role as cap rock, the strength of which increases with depth. The lower layer with good secondary porosity due to weathering and leaching can form the stratigraphic truncation traps. A typical stratigraphic reservoir lying in the unconformity between the Jurassic and Triassic in the north-west margin of the Junggar basin was meticulously analyzed in order to reveal the key controlling factors. The results showed that the hydrocarbon distribution in the stratigraphic onlap reservoirs was controlled by the onlap line, the hydrocarbon distribution in the stratigraphic truncation reservoirs was confined by the truncation line, and the mid layer acted as the key sealing rock. So a conclusion was drawn that "two lines (onlap line and truncation line) and a body (unconformity structural body)" control the formation and distribution of stratigraphic reservoirs.

  20. Comparison of phylogeographic structure and population history of two Phrynocephalus species in the Tarim Basin and adjacent areas.

    Science.gov (United States)

    Zhang, Qian; Xia, Lin; He, Jingbo; Wu, Yonghua; Fu, Jinzhong; Yang, Qisen

    2010-12-01

    An aridification of the Tarim Basin and adjacent areas since middle Pleistocene has produced significant genetic structuring of the local fauna. We examined the phylogeographic patterns, population structure and history of Phrynocephalus axillaris and Phrynocephalus forsythii using a mitochondrial fragment ND4-tRNA(LEU). Phylogenetic hypotheses were constructed using maximum parsimony and Bayesian inference, and the divergence times of major lineages were estimated by BEAST. Population structure and history were inferred by nested clade analysis, neutrality tests, mismatch distribution, and isolation by distance analysis. The two species might have experienced different evolutionary history throughout their current distribution. For P. forsythii, a vicariant event, as a consequence of geological isolation and desert expansion, might have produced the significant divergence between the Tarim and the Yanqi populations. For P. axillaris, populations of the Yanqi, Turpan and Hami Basins might have been established through dispersal during demographic expansion. Climatic fluctuations caused alternate expansion and shrinkage of rivers and oases several times, which likely led to habitat fragmentation for both species. Interaction between vicariance, dispersal and habitat fragmentation produced the current distribution and genetic diversity. The observed difference between the two species may be due partially to their different reproductive modes (ovoviviparous vs. oviparous). Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Basement control in the development of the early cretaceous West and Central African rift system

    Science.gov (United States)

    Maurin, Jean-Christophe; Guiraud, René

    1993-12-01

    The structural framework of the Precambrian basement of the West and Central African Rift System (WCARS) is described in order to examine the role of ancient structures in the development of this Early Cretaceous rift system. Basement structures are represented in the region by large Pan-African mobile belts (built at ca. 600 Ma) surrounding the > 2 Ga West African, Congo and Sao Francisco cratons. Except for the small Gao trough (eastern Mali) located near the contact nappe of the Pan-African Iforas suture zone along the edge of the West African craton, the entire WCARS is located within the internal domains of the Pan-African mobile belts. Within these domains, two main structural features occur as the main basement control of the WCARS: (1) an extensive network of near vertical shear zones which trend north-south through the Congo, Brazil, Nigeria, Niger and Algeria, and roughly east-west through northeastern Brazil and Central Africa. The shear zones correspond to intra-continental strike-slip faults which accompanied the oblique collision between the West African, Congo, and Sao Francisco cratons during the Late Proterozoic; (2) a steep metamorphic NW-SE-trending belt which corresponds to a pre-Pan-African (ca. 730 Ma) ophiolitic suture zone along the eastern edge of the Trans-Saharian mobile belt. The post-Pan-African magmatic and tectonic evolution of the basement is also described in order to examine the state of the lithosphere prior to the break-up which occurred in the earliest Cretaceous. After the Pan-African thermo-tectonic event, the basement of the WCARS experienced a long period of intra-plate magmatic activity. This widespread magmatism in part relates to the activity of intra-plate hotspots which have controlled relative uplift, subsidence and occasionally block faulting. During the Paleozoic and the early Mesozoic, this tectonic activity was restricted to west of the Hoggar, west of Aïr and northern Cameroon. During the Late Jurassic

  2. Basement depressurization using dwelling mechanical exhaust ventilation system

    International Nuclear Information System (INIS)

    Collignan, B.; O'Kelly, P.; Pilch, E.

    2004-01-01

    The mechanical ventilation exhaust system is commonly used in France to generate air renewal into building and especially into dwelling. It consists of a permanent mechanical air extraction from technical rooms (kitchen, bathrooms and toilets) using a unique fan connected to exhaust ducts. Natural air inlets in living room and bed rooms ensure an air flow from living spaces towards technical rooms. To fight against radon into building, the most recognised efficient technique is the Soil Depressurization System (S.D.S.) consisting in depressurizing the house basement. The aim of this study is to test the ability of the dwelling mechanical ventilation system to depressurize the basement in conjunction with air renewal of a house. For that purpose, a S.D.S. has been installed in an experimental house at CSTB during its construction. At first, tests undertaken with a variable velocity fan connected to the S.D.S. have characterised the permeability of the basement. It is shown that basement can be depressurized adequately with a relatively low air flow rate. At a second stage, S.D.S. has been connected to the exhaust ventilation fan used for the mechanical ventilation of the house. Results obtained show the ability of such ventilation system to generate sufficient depressurization in the basement and to ensure simultaneously adequate air change rate in the dwelling. (author)

  3. Geothermal Resource Analysis and Structure of Basin and Range Systems, Especially Dixie Valley Geothermal Field, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    David Blackwell; Kenneth Wisian; Maria Richards; Mark Leidig; Richard Smith; Jason McKenna

    2003-08-14

    Publish new thermal and drill data from the Dizie Valley Geothermal Field that affect evaluation of Basin and Range Geothermal Resources in a very major and positive way. Completed new geophysical surveys of Dizie Valley including gravity and aeromagnetics and integrated the geophysical, seismic, geological and drilling data at Dizie Valley into local and regional geologic models. Developed natural state mass and energy transport fluid flow models of generic Basin and Range systems based on Dizie Valley data that help to understand the nature of large scale constraints on the location and characteristics of the geothermal systems. Documented a relation between natural heat loss for geothermal and electrical power production potential and determined heat flow for 27 different geothermal systems. Prepared data set for generation of a new geothermal map of North American including industry data totaling over 25,000 points in the US alone.

  4. Structural controls on fractured coal reservoirs in the southern Appalachian Black Warrior foreland basin

    Energy Technology Data Exchange (ETDEWEB)

    Groshong, R.H.; Pashin, J.C.; McIntyre, M.R. [University of Alabama, Tuscaloosa, AL (United States). Dept. of Geological Science

    2009-09-15

    Coal is a nearly impermeable rock type for which the production of fluids requires the presence of open fractures. Basin-wide controls on the fractured coal reservoirs of the Black Warrior foreland basin are demonstrated by the variability of maximum production rates from coalbed methane wells. Reservoir behavior depends on distance from the thrust front. Far from the thrust front, normal faults are barriers to fluid migration and compartmentalize the reservoirs. Close to the thrust front, rates are enhanced along some normal faults, and a new trend is developed. The two trends have the geometry of conjugate strike-slip faults with the same sigma(1) direction as the Appalachian fold-thrust belt and are inferred to be the result of late pure-shear deformation of the foreland. Face cleat causes significant permeability anisotropy in some shallow coal seams but does not produce a map-scale production trend.

  5. Structural controls on fractured coal reservoirs in the southern Appalachian Black Warrior foreland basin

    Science.gov (United States)

    Groshong, Richard H., Jr.; Pashin, Jack C.; McIntyre, Marcella R.

    2009-09-01

    Coal is a nearly impermeable rock type for which the production of fluids requires the presence of open fractures. Basin-wide controls on the fractured coal reservoirs of the Black Warrior foreland basin are demonstrated by the variability of maximum production rates from coalbed methane wells. Reservoir behavior depends on distance from the thrust front. Far from the thrust front, normal faults are barriers to fluid migration and compartmentalize the reservoirs. Close to the thrust front, rates are enhanced along some normal faults, and a new trend is developed. The two trends have the geometry of conjugate strike-slip faults with the same σ1 direction as the Appalachian fold-thrust belt and are inferred to be the result of late pure-shear deformation of the foreland. Face cleat causes significant permeability anisotropy in some shallow coal seams but does not produce a map-scale production trend.

  6. Evaluation of seismic reflection data in the Davis and Lavender Canyons study area, Paradox Basin, Utah

    International Nuclear Information System (INIS)

    Kitcho, C.A.; Wong, I.G.; Turcotte, F.T.

    1986-08-01

    Seismic reflection data purchased from petroleum industry brokers and acquired through group speculative surveys were interpreted for information on the regional subsurface geologic structure and stratigraphy within and surrounding the Davis and Lavender Canyons study area in the Paradox Basin of southeastern Utah. Structures of interest were faults, folds, joints, and collapse structures related to salt dissolution. The seismic reflection data were used to interpret stratigraphy by identifying continuous and discontinuous reflectors on the seismic profiles. Thickening and thinning of strata and possible areas of salt flowage or dissolution could be identified from the seismic data. Identifiable reflectors included the tops of the Precambrian and Mississippian, a distinctive interbed close to the middle of the Pennsylvanian Paradox salt formation (probably the interval between Salt Cycles 10 and 13), and near the top of the Paradox salt. Of the 56 faults identified from the seismic reflection interpretation, 33 trend northwest, west-northwest, or west, and most affect only the deeper part of the stratigraphic section. These faults are part of the deep structural system found throughout the Paradox Basin, including the fold and fault belt in the northeast part of the basin. The faults bound basement Precambrian blocks that experienced minor activity during Mississippian and early Pennsylvanian deposition, and showed major displacement during early Paradox salt deposition as the Paradox Basin subsided. Based on the seismic data, most of these faults appear to have an upward terminus between the top of the Mississippian and the salt interbed reflector

  7. Effects of increased nitrogen availability on the structure and functioning of a mediterranean Basin maquis

    OpenAIRE

    Dias, Maria Teresa Machado, 1979-

    2012-01-01

    Tese de doutoramento, Biologia (Ecofisiologia), Universidade de Lisboa, Faculdade de Ciências, 2012 Increased N availability, resulting from agro-industrial activities, affects ecosystems’ stability. Mediterranean Basin ecosystems are biodiversity hotspots threatened by N deposition, however, little or no information is available on their responses to increased N. The general aim of this thesis was to develop an integrated system-level approach to study the responses of a Mediterranean Bas...

  8. Geometry and structure of the pull-apart basins developed along the western South American-Scotia plate boundary (SW Atlantic Ocean)

    Science.gov (United States)

    Esteban, F. D.; Tassone, A.; Isola, J. I.; Lodolo, E.; Menichetti, M.

    2018-04-01

    The South American-Scotia plate boundary is a left-lateral fault system which runs roughly E-W for more than 3000 km across the SW Atlantic Ocean and the Tierra del Fuego Island, reaching to the west the southern Chile Trench. Analyses of a large dataset of single- and multi-channel seismic reflection profiles acquired offshore has allowed to map the trace of the plate boundary from Tierra del Fuego to the Malvinas Trough, a tectonic depression located in the eastern part of the fault system, and to reconstruct the shape and geometry of the basins formed along the principal displacement zone of the fault system. Three main Neogene pull-apart basins that range from 70 to 100 km in length, and from 12 to 22 km in width, have been identified along this segment of the plate boundary. These basins have elongated shapes with their major axes parallel to the ENE-WSW direction of the fault zone. The sedimentary architecture and the infill geometry of the basins suggest that they represent mostly strike-slip dominated transtension basins which propagated from E to W. The basins imaged by seismic data show in some cases geometrical and structural features linked to the possible reactivation of previous wedge-top basins and inherited structures pertaining to the external front of the Magallanes fold-and-thrust compression belt, along which the South American-Scotia fault system has been superimposed. It is suggested that the sequence of the elongated basins occur symmetrically to a thorough going strike-slip fault, in a left-stepping geometrical arrangement, in a manner similar to those basins seen in other transcurrent environments.

  9. An empirical method for determining average soil infiltration rates and runoff, Powder River structural basin, Wyoming

    Science.gov (United States)

    Rankl, James G.

    1982-01-01

    This report describes a method to estimate infiltration rates of soils for use in estimating runoff from small basins. Average rainfall intensity is plotted against storm duration on log-log paper. All rainfall events are designated as having either runoff or nonrunoff. A power-decay-type curve is visually fitted to separate the two types of rainfall events. This separation curve is an incipient-ponding curve and its equation describes infiltration parameters for a soil. For basins with more than one soil complex, only the incipient-ponding curve for the soil complex with the lowest infiltration rate can be defined using the separation technique. Incipient-ponding curves for soils with infiltration rates greater than the lowest curve are defined by ranking the soils according to their relative permeabilities and optimizing the curve position. A comparison of results for six basins produced computed total runoff for all events used ranging from 16.6 percent less to 2.3 percent more than measured total runoff. (USGS)

  10. Structural evolution of Cenozoic basins in northeastern Tunisia, in response to sinistral strike-slip movement on the El Alia-Teboursouk Fault

    Science.gov (United States)

    Bejaoui, Hamida; Aïfa, Tahar; Melki, Fetheddine; Zargouni, Fouad

    2017-10-01

    This paper resolves the structural complexity of Cenozoic sedimentary basins in northeastern Tunisia. These basins trend NE-SW to ∼ E-W, and are bordered by old fracture networks. Detailed descriptions of the structural features in outcrop and in subsurface data suggest that the El Alia-Teboursouk Fault zone in the Bizerte area evolved through a series of tectonic events. Cross sections, lithostratigraphic correlations, and interpretation of seismic profiles through the basins show evidence for: (i) a Triassic until Jurassic-Early Cretaceous rifting phase that induced lateral variations of facies and strata thicknesses; (ii) a set of faults oriented NE-SW, NW-SE, N-S, and E-W that guided sediment accumulation in pull-apart basins, which were subject to compressive and transpressive deformation during Eocene (Lutetian-Priabonian), Miocene (Tortonian), and Pliocene-Quaternary; and (iii) NNW-SSE to NS contractional events that occurred during the Late Pliocene. Part of the latest phase has been the formation of different synsedimentary folded structures with significant subsidence inversion. Such events have been responsible for the reactivation of inherited faults, and the intrusion of Triassic evaporites, ensuring the role of a slip layer. The combined effects of the different paleoconstraints and halokinetic movements are at the origin of the evolution of these pull-apart basins. The subsurface data suggest that an important fault displacement occurred during the Mesozoic-Cenozoic. The patterns of sediment accumulation in the different basins reflect a high activity of deep ancient faults.

  11. Basement depth and sedimentary infill from deep seismic reflection data at the western tip of the offshore Corinth Rift

    Science.gov (United States)

    Beckers, Arnaud; Tripsanas, Efthymios; Hubert-Ferrari, Aurélia; Beck, Christian; Sakellariou, Dimitris

    2015-04-01

    The Corinth rift is a young continental rift located in central Greece. The active part of the rift forms an E-W striking depression - the Gulf of Corinth - that is the deepest in its central part. Extensive seismic surveys have imaged the basin's basement and allowed to estimate the total extension across most of the Gulf except its western tip. Extension is high in the central part and decreases westward and eastward, as reflected in the present-day bathymetry. Two decades of GPS measurements have shown that the extension rate increases westwards from ~5 to 10-15 mm yr-1, but this is not consistent with the long term pattern. However, no data allowed so far to estimate the basement depth at the western tip of the Gulf, where the geodetic extension rate is the largest. Such data would allow to check the apparent inconsistency between the present rate and the long-term estimates of crustal extension. We present here an unpublished multichannel seismic line dating from 1979 and crossing the western tip of the Gulf of Corinth. The line is 22 km long and strikes WNW-ESE, from the Mornos delta to the West-Channel fault. A Maxipulse source has been used, allowing to image the basement below the synrift sedimentary infill. To the east, a ~1.6 km deep basin is imaged between the southern margin of the Gulf and an inactive south-dipping fault located between the Aigion and the Trizonia faults. The sedimentary infill consists in an alternation between basin-focused bodies made of incoherent reflections and more extensive high-amplitude reflectors. Attributing this alternation to eustatic variations give an age of 300-350 ka to the oldest well imaged deposits. Northwest of the Trizonia fault, the basement is imaged at shallower depth, i.e. ~450 m. The western tip of the seismic line reaches the Mornos delta, close to the northern shoreline. There, the depth to the basement is larger, reaching ~1.2 km. The infill is made of 3 units : on the basement lies a thin unit of

  12. Evaluating the effects of model structure and meteorological input data on runoff modelling in an alpine headwater basin

    Science.gov (United States)

    Schattan, Paul; Bellinger, Johannes; Förster, Kristian; Schöber, Johannes; Huttenlau, Matthias; Kirnbauer, Robert; Achleitner, Stefan

    2017-04-01

    Modelling water resources in snow-dominated mountainous catchments is challenging due to both, short concentration times and a highly variable contribution of snow melt in space and time from complex terrain. A number of model setups exist ranging from physically based models to conceptional models which do not attempt to represent the natural processes in a physically meaningful way. Within the flood forecasting system for the Tyrolean Inn River two serially linked hydrological models with differing process representation are used. Non- glacierized catchments are modelled by a semi-distributed, water balance model (HQsim) based on the HRU-approach. A fully-distributed energy and mass balance model (SES), purpose-built for snow- and icemelt, is used for highly glacierized headwater catchments. Previous work revealed uncertainties and limitations within the models' structures regarding (i) the representation of snow processes in HQsim, (ii) the runoff routing of SES, and (iii) the spatial resolution of the meteorological input data in both models. To overcome these limitations, a "strengths driven" model coupling is applied. Instead of linking the models serially, a vertical one-way coupling of models has been implemented. The fully-distributed snow modelling of SES is combined with the semi-distributed HQsim structure, allowing to benefit from soil and runoff routing schemes in HQsim. A monte-carlo based modelling experiment was set up to evaluate the resulting differences in the runoff prediction due to the improved model coupling and a refined spatial resolution of the meteorological forcing. The experiment design follows a gradient of spatial discretisation of hydrological processes and meteorological forcing data with a total of six different model setups for the alpine headwater basin of the Fagge River in the Tyrolean Alps. In general, all setups show a good performance for this particular basin. It is therefore planned to include other basins with differing

  13. Part I: Neoacadian to Alleghanian foreland basin development and provenance in the central appalachian orogen, pine mountain thrust sheet Part II: Structural configuration of a modified Mesozoic to Cenozoic forearc basin system, south-central Alaska

    Science.gov (United States)

    Robertson, Peter Benjamin

    of south-central Alaska is an area of active convergence where the Pacific plate is being subducted at a low angle beneath the North American plate. In the Matanuska Valley of south-central Alaska, the geology of the Mesozoic to Cenozoic Matanuska forearc basin system records a complex collisional history along the margin from Cretaceous to Miocene time and provides an opportunity to study how shallow-angle subduction affects upper plate processes. Paleocene-Eocene low-angle subduction of an eastward migrating spreading ridge and Oligocene oceanic plateau subduction caused uplift, deformation, and slab window magmatic intrusion and volcanism in the Matanuska Valley region, thereby modifying the depositional environment and structure of the forearc system. In this study, detailed field mapping in the Matanuska Valley region and structural analysis of Paleocene-Eocene nonmarine sedimentary strata are utilized to better understand the structural response of the forearc basin system to multi-stage flat-slab subduction beneath an accreted continental margin, a process observed along multiple modern convergent margins. Four geologic maps and structural cross-sections from key areas along the peripheries of the Matanuska Valley area and one regional cross-section across the forearc system are presented to delineate its local structural configuration and to contribute to a more complete understanding of how sedimentary and tectonic processes along modern convergent margins may be or have been impacted by shallow-angle type and related subduction processes.

  14. Glomerular basement membrane composition and the filtration barrier.

    Science.gov (United States)

    Miner, Jeffrey H

    2011-09-01

    The glomerular basement membrane (GBM) is an especially thick basement membrane that contributes importantly to the kidney's filtration barrier. The GBM derives from the fusion of separate podocyte and endothelial cell basement membranes during glomerulogenesis and consists primarily of laminin-521 (α5β2γ1), collagen α3α4α5(IV), nidogens-1 and -2, and agrin. Of these nine proteins, mutations in the genes encoding four of them (LAMB2, COL4A3, COL4A4, and COL4A5) cause glomerular disease in humans as well as in mice. Furthermore, mutation of a fifth (Lama5) gene in podocytes in mice causes proteinuria, nephrotic syndrome, and progression to renal failure. These results highlight the importance of the GBM for establishing and maintaining a properly functioning glomerular filtration barrier.

  15. Mouse endometrial stromal cells produce basement-membrane components

    DEFF Research Database (Denmark)

    Wewer, U M; Damjanov, A; Weiss, J

    1986-01-01

    . Mouse decidual cells isolated from 6- to 7-day pregnant uteri explanted in vitro continue to synthesize basement-membrane-like extracellular matrix. Using immunohistochemistry and metabolic labeling followed by immunoprecipitation, SDS-PAGE, and fluorography, it was shown that the decidual cells...... to undergo pseudodecidualization. We thus showed that stromal cells from pregnant and nonpregnant mouse uteri synthesize significant amounts of basement-membrane components in vitro, and hence could serve as a good model for the study of normal basement-membrane components.......During mouse pregnancy, uterine stromal cells transform into morphologically distinct decidual cells under the influence of the implanting embryo and a proper hormonal environment. Mechanical stimulation of hormonally primed uterine stromal cells leads to the same morphologic alterations...

  16. New insights into the structure and stratigraphy of the Swedish sector of the Baltic Sea sedimentary Basin from vintage 2D marine seismic data

    Science.gov (United States)

    Sopher, Daniel; Juhlin, Christopher; Erlström, Mikael

    2014-05-01

    A large dataset originally acquired by the Swedish Oil Prospecting CO. (OPAB) between 1970 and 1990 including 2D marine seismic data, well log data, core data and seismic interpretations has recently been made available by the Swedish Geological Survey (SGU). In this study this dataset has been used to produce a set of regional geoseismic sections across the Swedish sector of the Baltic Sea. Regional depth structure maps detailing the deep structure of the basin produced from previous interpretations are also presented. The Baltic Sea Basin is an intra-cratonic basin located in northern Europe. The Swedish sector of the basin is characterised primarily by two structural elements, the Hanö Bay Basin and the Baltic Syneclise. The largest of these, the Baltic Syneclise, is a large synclinal depression formed during the Caledonian Orogeny. The Hanö Bay Basin was formed during the Mesozoic due to subsidence along the Christiansø Fault Zone. The Swedish sector of the Baltic Sea Basin is primarily characterised by a sequence of shallow marine Cambrian sediments overlain by a relatively thin succession of Ordovician marine limestone and marls; these are in turn overlain by a thick layer of marl, siltstone and claystone deposited during the Silurian. Mesozoic sediments are found in the Hanö Bay and outer Hanö Bay area. These were deposited in areas of local subsidence, associated with transtensional tectonics prevalent within and adjacent to the Tornquist Zone, during the Late Carboniferous/Early Permian. Block faulting occurring throughout the Mesozoic also affected sedimentation patterns in the area. In this study a sparse grid of marine seismic reflection profiles have been reprocessed across the Swedish sector of the Baltic Sea Basin. These have been interpreted based on the available well data and synthetic seismograms. Several regional seismic profiles were constructed which detail the major structural elements and basin stratigraphy across the Swedish sector. A

  17. Mesozoic architecture of a tract of the European-Iberian continental margin: Insights from preserved submarine palaeotopography in the Longobucco Basin (Calabria, Southern Italy)

    Science.gov (United States)

    Santantonio, Massimo; Fabbi, Simone; Aldega, Luca

    2016-01-01

    The sedimentary successions exposed in northeast Calabria document the Jurassic-Early Cretaceous tectonic-sedimentary evolution of a former segment of the European-Iberian continental margin. They are juxtaposed today to units representing the deformation of the African and Adriatic plates margins as a product of Apenninic crustal shortening. A complex pattern of unconformities reveals a multi-stage tectonic evolution during the Early Jurassic, which affected the facies and geometries of siliciclastic and carbonate successions deposited in syn- and post-rift environments ranging from fluvial to deep marine. Late Sinemurian/Early Pliensbachian normal faulting resulted in exposure of the Hercynian basement at the sea-floor, which was onlapped by marine basin-fill units. Shallow-water carbonate aprons and reefs developed in response to the production of new accommodation space, fringing the newborn islands which represent structural highs made of Paleozoic crystalline and metamorphic rock. Their drowning and fragmentation in the Toarcian led to the development of thin caps of Rosso Ammonitico facies. Coeval to these deposits, a thick (> 1 km) hemipelagic/siliciclastic succession was sedimented in neighboring hanging wall basins, which would ultimately merge with the structural high successions. Footwall blocks of the Early Jurassic rift, made of Paleozoic basement and basin-margin border faults with their onlapping basin-fill formations, are found today at the hanging wall of Miocene thrusts, overlying younger (Middle/Late Jurassic to Late Paleogene) folded basinal sediments. This paper makes use of selected case examples to describe the richly diverse set of features, ranging from paleontology to sedimentology, to structural geology, which are associated with the field identification of basin-margin unconformities. Our data provide key constraints for restoring the pre-orogenic architecture of a continental margin facing a branch of the Liguria-Piedmont ocean in the

  18. Time-term analysis of upper crustal structure in the Columbia Basin, Washington

    International Nuclear Information System (INIS)

    Rohay, A.C.; Glover, D.W.; Malone, S.D.

    1985-04-01

    Arrival time data from existing permanent networks and supplementary portable stations were collected during the US Geological Survey (USGS) refraction program in August 1984. Reduced travel time plots of these data and USGS record sections were used to select data from two branches of the travel time curve. Sixty-six arrival times selected in the distance range 3 to 63 km were fit to a velocity of 5.16 km/s (+-0.02 km/s). Time terms determined at 31 stations range from -0.10 to +0.15 s (+-0.05 s) and show correlations with elevation and near-surface geology. The four intercept times range from 0.15 to 0.22 s (+-0.05 s), implying an average depth of 0.5 km to the 5.16-km/s refracting horizon within the basalt. Eighty-three arrival times selected in the distance range 50 to 145 km were fit to a velocity of 6.16 km/s (+-0.02 km/s). Time terms calculated at 40 stations range from -0.6 to +0.6 s (+-0.1 s), with the four intercept times ranging from 1.4 to 2.0 s(+-0.1 s). These show a systematic regional pattern consistent with previous studies (Malone and Rohay 1983) but extended by portable-station coverage. Conversion of the time terms to basement depth is dependent upon the lateral extent of an inferred low-velocity layer beneath the basalts, which is suggested by deep-borehole logs and magnetotelluric data

  19. Coarctation induces alterations in basement membranes in the cardiovascular system

    DEFF Research Database (Denmark)

    Lipke, D W; McCarthy, K J; Elton, T S

    1993-01-01

    A coarctation hypertensive rat model was used to examine the effects of elevated blood pressure on basement membrane component synthesis by cardiac myocytes and aorta using immunohistochemistry and Northern blot analysis. Carotid arterial pressure increased immediately on coarctation, and left...... with regard to protein and tissue type affected as well as intensity of the changes. However, changes in mRNA levels (but not protein deposition) for perlecan and type IV collagen were also observed in aortas from hypertensive rats compared with controls. Increases in steady-state mRNA levels for all basement...

  20. Nevada Isostatic Residual Gravity Over Basement

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study of gravity data from Nevada is part of a statewide analysis of mineral resources. The main objective of the gravity study were: 1) to infer the structure...

  1. Piezometric levels as possible indicator of aquifer structure: analysis of the data from Maknassy basin aquifer system (Central Tunisia)

    International Nuclear Information System (INIS)

    Chenini, Ismail; Mammou, Abdallah Ben; Turki, Mohamed Moncef; Mercier, Eric

    2010-01-01

    The knowledge of piezometric data is of vast interest in many applications, such as assessing groundwater flow direction and identifying recharge zone of the aquifer. In this paper, a methodology is presented as a complementary approach to characterize multilayered aquifer system structure and functioning using piezometric data and the cartography of the hydraulic charge difference. The methodology is presented to gradually discriminate the aquifer system levels and to evaluate the spatial distribution of hydraulic heads. The hydraulic charge difference mapping permits to track spatial evolution of the impermeable levels. The methodology has been applied over the Maknassy basin aquifer system, located in central Tunisia. The obtained results, showing the multilayered aquifer structure, are validated using hydrochemical approach and piezometric data not considered in the reasoning. (author

  2. Application of morphometry in neotectonic studies at the eastern edge of the Paraná Basin, Santa Catarina State, Brazil

    Science.gov (United States)

    Jacques, Patricia D.; Salvador, Elizete D.; Machado, Rômulo; Grohmann, Carlos H.; Nummer, Alexis R.

    2014-05-01

    The neotectonic evolution of the eastern edge of the Paraná Basin in the Santa Catarina State, Brazil was investigated using field data and detailed morphometric analysis along an east-west section. Analysis included generation of maps of isobase, hydraulic gradients, hypsometry, incision of drainage basins, drainage asymmetry and anomalous morphological features. All these maps generated results that agreed with field data and helped define recent faults in directions close to N-S and E-W, both probably reactivated faults of the Paraná Basin and the basement. Geomorphological features identified in topographic maps, possibly related to neotectonism, have a close agreement with our observations in the field. The asymmetry of basins as analysed by the T-Index method proved to be compatible with the influence of a E-W compressive tectonic regime and showed a movement from W to E. Application of the hypsometric integral technique helped establish a correlation between the younger basins with structures trending N-S (± 30°). The N-S faults were related to a compressional stress field (SHmax) close to E-W and SHmin (stress minimum) around N-S, thereby establishing a tectonic context of structures developed in a transpressive regime. The compressional field was caused by the subduction of the Nazca tectonic plate below the South American plate, whereas the transcurrent component exploited pre-existent E-W structures when the Atlantic Ocean was opening.

  3. Structure of Charnockitic basement in a part of the Krishna ...

    Indian Academy of Sciences (India)

    movements of faulted blocks of EGMB. In the present investigation an area of 8000km. 2 of EGMB lying .... on its north also by positive anomalies, as sug- gested by the few conspicuous linear positive anom- aly contours .... top of the faulted anomalous body can be expected to be encountered not shallower than 4.2km, and.

  4. Structure of Charnockitic basement in a part of the Krishna ...

    Indian Academy of Sciences (India)

    Department of Geophysics, Andhra University, Visakhapatnam 530 003, India. ∗ e-mail: ivr−murthy@yahoo.com. A regional magnetic survey was carried out over an area of 8000km. 2 in Godavari districts of. Andhra Pradesh, India, which is covered by the rocks of Eastern Ghat Mobile Belt (EGMB) viz., the Khondalitic series ...

  5. State policies and requirements for management of uranium mining and milling in New Mexico. Volume II. Water availability in the San Juan Structural Basin

    International Nuclear Information System (INIS)

    Vandevender, S.G.

    1980-04-01

    This volume contains Two parts: Part One is an analysis of an issue paper prepared by the office of the New Mexico State Engineer on water availability for uranium production. Part Two is the issue paper itself. The State Engineer's report raises the issue of a scarce water supply in the San Juan Structural Basin acting as a constraint on the growth of the uranium mining and milling industry in New Mexico. The water issue in the structural basin is becoming an acute policy issue because of the uranium industry's importance to and rapid growth within the structural basin. Its growth places heavy demands on the region's scarce water supply. The impact of mine dewatering on water supply is of particular concern. Much of the groundwater has been appropriated or applied for. The State Engineer is currently basing water rights decisions upon data which he believes to be inadequate to determine water quality and availability in the basin. He, along with the USGS and the State Bureau of Mines and Mineral Resources, recommends a well drilling program to acquire the additional information about the groundwater characteristics of the basin. The information would be used to provide input data for a computer model, which is used as one of the bases for decisions concerning water rights and water use in the basin. The recommendation is that the appropriate DOE office enter into discussions with the New Mexico State Engineer to explore the potential mutual benefits of a well drilling program to determine the water availability in the San Juan Structural Basin

  6. Initiation, evolution and extinction of pull-apart basins: Implications for opening of the Gulf of California

    Science.gov (United States)

    van Wijk, J.; Axen, G.; Abera, R.

    2017-11-01

    We present a model for the origin, crustal architecture, and evolution of pull-apart basins. The model is based on results of three-dimensional upper crustal elastic models of deformation, field observations, and fault theory, and is generally applicable to basin-scale features, but predicts some intra-basin structural features. Geometric differences between pull-apart basins are inherited from the initial geometry of the strike-slip fault step-over, which results from the forming phase of the strike-slip fault system. As strike-slip motion accumulates, pull-apart basins are stationary with respect to underlying basement, and the fault tips propagate beyond the rift basin, increasing the distance between the fault tips and pull-apart basin center. Because uplift is concentrated near the fault tips, the sediment source areas may rejuvenate and migrate over time. Rift flank uplift results from compression along the flank of the basin. With increasing strike-slip movement the basins deepen and lengthen. Field studies predict that pull-apart basins become extinct when an active basin-crossing fault forms; this is the most likely fate of pull-apart basins, because basin-bounding strike-slip systems tend to straighten and connect as they evolve. The models show that larger length-to-width ratios with overlapping faults are least likely to form basin-crossing faults, and pull-apart basins with this geometry are thus most likely to progress to continental rupture. In the Gulf of California, larger length-to-width ratios are found in the southern Gulf, which is the region where continental breakup occurred rapidly. The initial geometry in the northern Gulf of California and Salton Trough at 6 Ma may have been one of widely-spaced master strike-slip faults (lower length-to-width ratios), which our models suggest inhibits continental breakup and favors straightening of the strike-slip system by formation of basin-crossing faults within the step-over, as began 1.2 Ma when the

  7. Surface analogue outcrops of deep fractured basement reservoirs in extensional geological settings. Examples within active rift system (Uganda) and proximal passive margin (Morocco).

    Science.gov (United States)

    Walter, Bastien; Géraud, Yves; Diraison, Marc

    2014-05-01

    The important role of extensive brittle faults and related structures in the development of reservoirs has already been demonstrated, notably in initially low-porosity rocks such as basement rocks. Large varieties of deep-seated resources (e.g. water, hydrocarbons, geothermal energy) are recognized in fractured basement reservoirs. Brittle faults and fracture networks can develop sufficient volumes to allow storage and transfer of large amounts of fluids. Development of hydraulic model with dual-porosity implies the structural and petrophysical characterization of the basement. Drain porosity is located within the larger fault zones, which are the main fluid transfer channels. The storage porosity corresponds both to the matrix porosity and to the volume produced by the different fractures networks (e.g. tectonic, primary), which affect the whole reservoir rocks. Multi-scale genetic and geometric relationships between these deformation features support different orders of structural domains in a reservoir, from several tens of kilometers to few tens of meters. In subsurface, 3D seismic data in basement can be sufficient to characterize the largest first order of structural domains and bounding fault zones (thickness, main orientation, internal architecture, …). However, lower order structural blocks and fracture networks are harder to define. The only available data are 1D borehole electric imaging and are used to characterize the lowest order. Analog outcrop studies of basement rocks fill up this resolution gap and help the understanding of brittle deformation, definition of reservoir geometries and acquirement of reservoir properties. These geological outcrop studies give information about structural blocks of second and third order, getting close to the field scale. This allows to understand relationships between brittle structures geometry and factors controlling their development, such as the structural inheritance or the lithology (e.g. schistosity, primary

  8. Biodiversity and community structure of zooplankton in the Sub-basin of Rio Poxim, Sergipe, Brazil

    Directory of Open Access Journals (Sweden)

    Eliane Maria de Souza Nogueira

    2011-08-01

    Full Text Available The zooplankton of aquatic environments is composed mostly of protozoans, rotifers, cladocerans and copepods, which play an important role in the food chain, transferring mass and energy from primary producers to higher trophic levels. This work was prepared with the objective of contributing to the knowledge of zooplankton biodiversity that occurs in the Sub-basin of Rio Poxim. Water samples were taken at monthly intervals at four sampling stations located along the sub-basin in the period August 2009 to July 2010. To obtain the zooplankton community, 100 L of water were filtered on nylon net with an aperture of 50 mm. Were identified 72 taxa distributed in the following taxonomic categories Rotifera, Protozoa, Porifera, Nematoda, Anellida, Cladocera, Copepoda, Ostracoda, Isopoda and Insecta. In terms of species richness, the phylum Rotifera followed by the Protoctista were the most relevant with forty and fifteen taxa, respectively. The most representative taxa in numerical terms were Arcella vulgaris, Notholca sp. Rotary sp. and nematodes. Regarding the community diversity index, the community was characterized as low diversity, but the taxa were distributed evenly in all monitoring points.

  9. The Tethys Rifting of the Valencia Trough Basin

    Science.gov (United States)

    Viñas, Marina; Ranero, César R.; Cameselle, Alejandra L.

    2017-04-01

    reaching deep into the sediment sequence, which provides an unprecedented view of the tectonic structure and distribution of synrift deposits across the entire basin, from the Iberian to the North Balearic margin (Figure 2). Here we first show that the seismic records provide full crustal-scale information. Later we discuss the tectonic and sedimentary structure that supports that crustal stretching and basin formation of the VTB occurred fundamentally during the Mesozoic times by strike-slip tectonics and not during Tertiary times by back-arc extension. We show that the current sea floor morphological configuration giving rise to the so-called Valencia Trough does not represent the changes in crystalline basement thickness related to rifting, but fundamentally a product of sediment dynamics, particularly by the development during post-Messinian times of the Ebro-river delta. Our results are significant to understand Tethyan rifting and need to be considered for plate kinematic reconstructions of the western Mediterranean.

  10. [Relationship between the changes in ischemia/reperfusion cerebro-microvessel basement membrane injury and gelatinase system in senile rat].

    Science.gov (United States)

    Li, Jian-sheng; Liu, Ke; Liu, Jing-xia; Wang, Ming-hang; Zhao, Yue-wu; Liu, Zheng-guo

    2008-11-01

    To study the relationship of cerebro-microvessel basement membrane injury and gelatinase system after cerebral ischemia/reperfusion (I/R) in aged rats. Cerebral I/R injury model was reproduced by intraluminal silk ligature thrombosis of the middle cerebral artery occlusion (MCAO). Rats were divided randomly into sham control and I/R groups in young rats [ischemia 3 hours (I 3 h) and reperfusion 6 hours (I/R 6 h), 12 hours (I/R 12 h), 24 hours (I/R 24 h), 3 days (I/R 3 d), 6 days (I/R 6 d)], and sham control group and I/R group in aged rats (I 3 h and I/R 6 h, I/R 12 h, I/R 24 h , I/R 3 d, I/R 6 d). The change in cerebro-cortex microvessel basement membrane structure, basement membrane type IV collagen (Col IV) and laminin (LN) contents, matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) expression in every group were determined with immunohistochemical method and zymogram analysis. With the increase in age, Col IV and LN contents of the microvessel basement membrane were increased, and MMP-2 and MMP-9 expressions were stronger. With prolongation of I/R, the degradation of microvessel basement membrane components (Col IV and LN) was positively correlated with the duration of cerebral I/R. MMP-2 expression was increased gradually, and MMP-9 and TIMP-1 expression increased at the beginning and decreased subsequently. Col IV(I 3 h, I/R 6 h , I/R 12 h), LN (I 3 h, I/R 6-24 h), MMP-2 (I 3 h, I/R 6 h-6 d) and MMP-9 (I 3 h, I/R 6-24 h) expression level in aged rats with I/R injury were higher, and TIMP-1 (I/R 24 h) expression was lower than those in young rats (Pcerebro-microvessel basement membrane in rats is related with MMPs and TIMP. Cerebro-microvessel basement membrane injury is more serious in aged rats than that of young rats. Changes in cerebro-microvessel basement membrane injury in aged rats is related with gelatinase system change.

  11. Stratigraphic and sedimentary evidences for development of Aptian intrashelf basin in the structural Zagros zone, northern Fars Platform

    Directory of Open Access Journals (Sweden)

    Neda Khoshfam

    2016-12-01

    Therefore despite previous visions, the Fars platform was not a monolith shallow platform. In addition, except Kazhdumi intrashelf basin, there were other deep and local intrashelf basins which were developed within the Fars platform.

  12. Clustering and interpretation of local earthquake tomography models in the southern Dead Sea basin

    Science.gov (United States)

    Bauer, Klaus; Braeuer, Benjamin

    2016-04-01

    The Dead Sea transform (DST) marks the boundary between the Arabian and the African plates. Ongoing left-lateral relative plate motion and strike-slip deformation started in the Early Miocene (20 MA) and produced a total shift of 107 km until presence. The Dead Sea basin (DSB) located in the central part of the DST is one of the largest pull-apart basins in the world. It was formed from step-over of different fault strands at a major segment boundary of the transform fault system. The basin development was accompanied by deposition of clastics and evaporites and subsequent salt diapirism. Ongoing deformation within the basin and activity of the boundary faults are indicated by increased seismicity. The internal architecture of the DSB and the crustal structure around the DST were subject of several large scientific projects carried out since 2000. Here we report on a local earthquake tomography study from the southern DSB. In 2006-2008, a dense seismic network consisting of 65 stations was operated for 18 months in the southern part of the DSB and surrounding regions. Altogether 530 well-constrained seismic events with 13,970 P- and 12,760 S-wave arrival times were used for a travel time inversion for Vp, Vp/Vs velocity structure and seismicity distribution. The work flow included 1D inversion, 2.5D and 3D tomography, and resolution analysis. We demonstrate a possible strategy how several tomographic models such as Vp, Vs and Vp/Vs can be integrated for a combined lithological interpretation. We analyzed the tomographic models derived by 2.5D inversion using neural network clustering techniques. The method allows us to identify major lithologies by their petrophysical signatures. Remapping the clusters into the subsurface reveals the distribution of basin sediments, prebasin sedimentary rocks, and crystalline basement. The DSB shows an asymmetric structure with thickness variation from 5 km in the west to 13 km in the east. Most importantly, a well-defined body

  13. Petrology and geotechnic setting of the basement comple rocks ...

    African Journals Online (AJOL)

    The basement complex, located at the south-eastern borders of Ogoja town in the south-eastern part of Nigeria, consists of two varieties of migmatitic gneisses, namely banded and augen gneisses, which, in some cases, are inter-layered with amphibolite. Many concordant to discordant quartzofeldspathic veins in these ...

  14. Groundwater Exploration in the Basement Complex Around Chibok ...

    African Journals Online (AJOL)

    A geophysical survey employing Schlumberger electrode configuration using vertical electrical sounding (VES) method was carried out around Chibok area within the Basement Complex of north-eastern Nigeria using an ABEM SAS 300C Terrameter with a view to exploring groundwater within the study area.

  15. Mouse endometrial stromal cells produce basement-membrane components

    DEFF Research Database (Denmark)

    Wewer, U M; Damjanov, A; Weiss, J

    1986-01-01

    . Mouse decidual cells isolated from 6- to 7-day pregnant uteri explanted in vitro continue to synthesize basement-membrane-like extracellular matrix. Using immunohistochemistry and metabolic labeling followed by immunoprecipitation, SDS-PAGE, and fluorography, it was shown that the decidual cells...

  16. Source parameter imaging from areomagnetic data of the basement ...

    African Journals Online (AJOL)

    Source parameter imaging from areomagnetic data of the basement rocks in part of the middle Benue trough, Nigeria. GC Onyedim, EA Ariyibi, MO Awoyemi, JB Arubayi, OM Afolabi. Abstract. No Abstract. Journal of Mining and Geology Vol. 42 (2) 2006: pp. 165-173. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT

  17. Aeromagnetic imaging of the basement morphology in part of the ...

    African Journals Online (AJOL)

    Aeromagnetic imaging of the basement morphology in part of the middle Benue trough, Nigeria. GC Onyedim, MO Awoyemi, EA Ariyibi, JB Arubayi. Abstract. No Abstract. Journal of Mining and Geology Vol. 42 (2) 2006: pp. 157-163. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

  18. Geoelectric characterization of Aquifer types in the basement ...

    African Journals Online (AJOL)

    Geoelectric characterization of Aquifer types in the basement complex terrain of parts of Osun state,Nigeria. S Bayode, JS Ojo, MO Olorunfemi. Abstract. No Abstract. Global Journal of Pure and Applied Sciences Vol. 12(3) 2006: 377-385. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT ...

  19. Hydraulic characteristics of a typical basement complex aquifer in ...

    African Journals Online (AJOL)

    Hydraulic characteristics of a typical basement complex aquifer in Ajaokuta, southwestern Nigeria. CC Osadebe, JO Fatoba, S Obrike. Abstract. No Abstract. Ife Journal of Science Vol. 7(2) 2005: 297-303. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  20. Coarctation induces alterations in basement membranes in the cardiovascular system

    DEFF Research Database (Denmark)

    Lipke, D W; McCarthy, K J; Elton, T S

    1993-01-01

    A coarctation hypertensive rat model was used to examine the effects of elevated blood pressure on basement membrane component synthesis by cardiac myocytes and aorta using immunohistochemistry and Northern blot analysis. Carotid arterial pressure increased immediately on coarctation, and left ve...

  1. Conceptual model of the uppermost principal aquifer systems in the Williston and Powder River structural basins, United States and Canada

    Science.gov (United States)

    Long, Andrew J.; Aurand, Katherine R.; Bednar, Jennifer M.; Davis, Kyle W.; McKaskey, Jonathan D.R.G.; Thamke, Joanna N.

    2014-01-01

    The three uppermost principal aquifer systems of the Northern Great Plains—the glacial, lower Tertiary, and Upper Cretaceous aquifer systems—are described in this report and provide water for irrigation, mining, public and domestic supply, livestock, and industrial uses. These aquifer systems primarily are present in two nationally important fossil-fuelproducing areas: the Williston and Powder River structural basins in the United States and Canada. The glacial aquifer system is contained within glacial deposits that overlie the lower Tertiary and Upper Cretaceous aquifer systems in the northeastern part of the Williston structural basin. Productive sand and gravel aquifers exist within this aquifer system. The Upper Cretaceous aquifer system is contained within bedrock lithostratigraphic units as deep as 2,850 and 8,500 feet below land surface in the Williston and Powder River structural basins, respectively. Petroleum extraction from much deeper formations, such as the Bakken Formation, is rapidly increasing because of recently improved hydraulic fracturing methods that require large volumes of relatively freshwater from shallow aquifers or surface water. Extraction of coalbed natural gas from within the lower Tertiary aquifer system requires removal of large volumes of groundwater to allow degasification. Recognizing the importance of understanding water resources in these energy-rich basins, the U.S. Geological Survey (USGS) Groundwater Resources Program (http://water.usgs.gov/ogw/gwrp/) began a groundwater study of the Williston and Powder River structural basins in 2011 to quantify this groundwater resource, the results of which are described in this report. The overall objective of this study was to characterize, quantify, and provide an improved conceptual understanding of the three uppermost and principal aquifer systems in energy-resource areas of the Northern Great Plains to assist in groundwater-resource management for multiple uses. The study area

  2. High-resolution temporal analysis of deep subseafloor microbial communities inhabiting basement fluids

    Science.gov (United States)

    Jungbluth, S.; Lin, H. T.; Hsieh, C. C.; Rappe, M. S.

    2014-12-01

    The temporal variation in microbial communities inhabiting the anoxic, sediment-covered basaltic ocean basement is largely uncharacterized due to the inaccessible nature of the environment and difficulties associated with collection of samples from low-biomass microbial habitats. Here, a deep sea instrumented platform was employed on the Juan de Fuca Ridge in the summer of 2013 to collect 46 samples of basement fluids from the most recent generation of borehole observatories (U1362A and B), which feature multiple sampling horizons at a single location and fluid delivery lines manufactured using stainless steel or inert polytetrafluoroethylene (PTFE) parts. Included were three time-series deployments of the GEOmicrobe sled meant to resolve the fine-scale (i.e. hourly) temporal variation within in situ crustal microbial communities. Illumina technology was used to sequence small subunit ribosomal RNA (SSU rRNA) gene fragments from sediment, seawater, and subseafloor fluids. Similar to has been reported previously, basic differences in the three environments was observed. Fluid samples from depth horizons extending 30, 70, and ~200 meters sub-basement revealed differences in the observed microbial communities, indicating potential depth-specific zonation of microorganisms in the basaltic basement fluids. Extensive overlap between microorganisms collected from a single depth horizon but using two fluid delivery lines manufactured with different materials was observed, though some differences were also noted. Several archaeal (e.g. THSCG, MCG, MBGE, Archaeoglobus) and bacterial (e.g. Nitrospiraceae, OP8, KB1) lineages detected in previous years of basement fluid sampling nearby were found here, which further supports the notion that these microorganisms are stable residents of anoxic basaltic subseafloor fluids. Direct cell enumeration of samples collected from U1362A and U1362B revealed an elevated biomass compared to samples at these locations from previous years

  3. Microbial diversity within Juan de Fuca ridge basement fluids sampled from oceanic borehole observatories

    Science.gov (United States)

    Jungbluth, S.; Bowers, R.; Lin, H.; Hsieh, C.; Cowen, J. P.; Rappé, M.

    2012-12-01

    Three generations of sampling and instrumentation platforms known as Circulation Obviation Retrofit Kit (CORK) observatories affixed to Ocean Drilling Program (ODP) and Integrated Ocean Drilling Program (IODP) boreholes are providing unrivaled access to fluids originating from 1.2-3.5 million-years (Myr) old basaltic crust of the eastern flank of the Juan de Fuca ridge. Borehole fluid samples obtained via a custom seafloor fluid pumping and sampling system coupled to CORK continuous fluid delivery lines are yielding critical insights into the biogeochemistry and nature of microbial life inhabiting the sediment-covered basement environment. Direct microscopic enumeration revealed microbial cell abundances that are 2-41% of overlying bottom seawater. Snapshots of basement fluid microbial diversity and community structure have been obtained through small subunit ribosomal RNA (SSU rRNA) gene cloning and sequencing from five boreholes that access a range of basement ages and temperatures at the sediment-basement interface. SSU rRNA gene clones were derived from four different CORK installations (1026B, 1301A, 1362A, and 1362B) accessing relatively warmer (65°C) and older (3.5 Myr) ridge flank, and one location (1025C) accessing relatively cooler (39°C) and younger (1.2 Myr) ridge flank, revealing that warmer basement fluids had higher microbial diversity. A sampling time-series collected from borehole 1301A has revealed a microbial community that is temporally variable, with the dominant lineages changing between years. Each of the five boreholes sampled contained a unique microbial assemblage, however, common members are found from both cultivated and uncultivated lineages within the archaeal and bacterial domains, including meso- and thermophilic microbial lineages involved with sulfur cycling (e.g Thiomicrospira, Sulfurimonas, Desulfocapsa, Desulfobulbus). In addition, borehole fluid environmental gene clones were also closely related to uncultivated lineages

  4. Geochemical variability of the Yucatan basement: Constraints from crystalline clasts in Chicxulub impactites

    Science.gov (United States)

    Kettrup, B.; Deutsch, A.

    2003-07-01

    The 65 Ma old Chicxulub impact structure with a diameter of about 180 km is again in the focus of the geosciences because of the recently commenced drilling of the scientific well Yaxcopoil- 1. Chicxulub is buried beneath thick post-impact sediments, yet samples of basement lithologies in the drill cores provide a unique insight into age and composition of the crust beneath Yucatan. This study presents major element, Sr, and Nd isotope data for Chicxulub impact melt lithologies and clasts of basement lithologies in impact breccias from the PEMEX drill cores C-1 and Y-6, as well as data for ejecta material from the K/T boundaries at La Lajilla, Mexico, and Furlo, Italy. The impact melt lithologies have an andesitic composition with significantly varying contents of Al, Ca, and alkali elements. Their present day 87Sr/86Sr ratios cluster at about 0.7085, and 143Nd/144Nd ratios range from 0.5123 to 0.5125. Compared to the melt lithologies that stayed inside the crater, data for ejecta material show larger variations. The 87Sr/86Sr ratios range from 0.7081 for chloritized spherules from La Lajilla to 0.7151 for sanidine spherules from Furlo. The 143Nd/144Nd ratio is 0.5126 for La Lajilla and 0.5120 for the Furlo spherules. In an tCHUR(Nd)-tUR(Sr) diagram, the melt lithologies plot in a field delimited by Cretaceous platform sediments, various felsic lithic clasts and a newly found mafic fragment from a suevite. Granite, gneiss, and amphibolite have been identified among the fragments from crystalline basement gneiss. Their 87Sr/86Sr ratios range from 0.7084 to 0.7141, and their 143Nd/144Nd ratios range from 0.5121 to 0.5126. The TNdDM model ages vary from 0.7 to 1.4 Ga, pointing to different source terranes for these rocks. This leads us to believe that the geological evolution and the lithological composition of the Yucatàn basement is probably more complex than generally assumed, and Gondwanan as well as Laurentian crust may be present in the Yucatàn basement.

  5. Geohydrology and potential effects of coal mining in 12 coal-lease areas, Powder River structural basin, northeastern Wyoming. Water Resources Investigation

    International Nuclear Information System (INIS)

    Fogg, J.L.; Martin, M.W.; Daddow, P.B.

    1991-01-01

    The purpose of the report is to describe the geohydrology of 12 coal-lease areas in the Powder River structural basin in relation to the mining proposed for each area. The description of the geohydrology of each of the lease areas focuses on the shallow ground-water system and includes identification of recharge and discharge areas, directions of ground-water movement, and potential effects of mining. The shallow ground-water system in the Powder River structural basin is not well defined because of the discontinuous nature of the aquifers in the basin. Understanding the ground-water hydrology of these 12 coal-lease areas will improve understanding of the shallow ground-water system in the basin. The first part of the report is a description of the general geohydrology of the Wyoming part of the Powder River structural basin. The second part of the report is a general discussion of the effects of coal mining on ground-water hydrology. The third part of the report contains site-specific discussions of the ground-water hydrology and potential effects of mining for each of the 12 coal-lease areas

  6. Hampton Butte, a 30-Ma rhyodacite basement high bounding the subsiding Miocene to Pliocene High Lava Plains of Oregon

    Science.gov (United States)

    Iademarco, M. J.; Grunder, A.

    2012-12-01

    Hampton Butte, a 30-Ma rhyodacite basement high bounding the subsiding Miocene to Pliocene High Lava Plains Michael J. Iademarco and Anita L. Grunder The Hampton Butte area of south central Oregon lies at the boundary between major volcanic and tectonic provinces. Hampton Butte is a large rhyodacite dome complex dated at 30.39 ± 0.13 Ma and is slightly older than the 28.63 ± 0.17 Ma dacite of Cougar Butte to the immediate southeast. They extend the known distribution of vent rocks of John Day age (~35-20 Ma) and are among the oldest rocks exposed in southeastern Oregon. Excepting a remnant of a Cretaceous pluton that intrudes metasedimentary rocks of uncertain age in southeasternmost Oregon, there are no pre-Oligocene basement rocks in the northwest corner of the Basin and Range. Hampton Butte is at least 70 km east of the inferred Oligocene arc indicating that, if it was part of early Cascade volcanism, the arc was much broader than today. Hampton Butte lies at the northern margin of the High Lava Plains, which extend from behind the Cascades arc ~300 km eastward and separate the northwest corner of the Basin a Range form relatively little extended Blue Mountains region to the north. Rocks of the High Lava Plains (HLP) range from ~10 to 0 Ma and are high alumina olivine tholeiites intercalated with tuffaceous sediments and thin widespread ash-flow tuffs; the HLP is punctuated by rhyolite dome complexes that are successively younger to the west. A stack of compound flows of HLP basalt are banked on the south flank of Hampton Butte and dip about 5 degrees south, toward the HLP. These basalts have an age of 7.75 ± 0.06 Ma and correlate with a tongue of basalt with an age of 7.81 ± 0.06, which is preserved in a paleovalley cut into Hampton Butte. These basalts are part of an HLP-wide episode of ~7.5-8 Ma basalt activity. The Hampton Tuff is also banked on the south flank of Hampton Butte, like the basalts dips 5-7 degrees south. The Hampton Tuff yields an age of 3

  7. Permeability structure and its influence on microbial activity at off-Shimokita basin, Japan

    Science.gov (United States)

    Tanikawa, W.; Yamada, Y.; Sanada, Y.; Kubo, Y.; Inagaki, F.

    2016-12-01

    The microbial populations and the limit of microbial life are probably limited by chemical, physical, and geological conditions, such as temperature, pore water chemistry, pH, and water activity; however, the key parameters affecting growth in deep subseafloor sediments remain unclarified (Hinrichs and Inagaki 2012). IODP expedition 337 was conducted near a continental margin basin off Shimokita Peninsula, Japan to investigate the microbial activity under deep marine coalbed sediments down to 2500 mbsf. Inagaki et al. (2015) discovered that microbial abundance decreased markedly with depth (the lowest cell density of pressure condition. Permeability was calculated by the steady state flow method by keeping differential pore pressure from 0.1 to 0.8 MPa.Our results show that the permeability for core samples decreases with depth from 10-16 m2 on the seafloor to 10-20 m2 at the bottom of hole. However, permeability is highly scattered within the coal bed unit (1900 to 2000 mbsf). Permeabilities for sandstone and coal is higher than those for siltstone and shale, therefore the scatter of the permeabilities at the same unit is due to the high variation of lithology. The highest permeability was observed in coal samples and this is probably due to formation of micro cracks (cleats). Permeability estimated from the NMR logging using the empirical parameters is around two orders of magnitude higher than permeability of core samples, even though the relative permeability variation at vertical direction is quite similar between core and logging data.The higher cell density is observed in the relatively permeable formation. On the other hand, the correlation between cell density, water activity, and porosity is not clear. On the assumption that pressure gradient is constant through the depth, flow rate can be proportional to permeability of sediments. Flow rate probably restricts the availability of energy and nutrient for microorganism, therefore permeability might have

  8. Late-Miocene thrust fault-related folding in the northern Tibetan Plateau: Insight from paleomagnetic and structural analyses of the Kumkol basin

    Science.gov (United States)

    Lu, Haijian; Fu, Bihong; Shi, Pilong; Xue, Guoliang; Li, Haibing

    2018-05-01

    Constraints on the timing and style of the Tibetan Plateau growth help spur new understanding of the tectonic evolution of the northern Tibetan Plateau and its relation to the India-Asia continental collision. In this regard, records of tectonic deformation with accurate ages are urgently needed, especially in regions without relevant studies. The Kumkol basin, located between two major intermontane basins (the Hoh Xil and Qaidam basins), may hold clues to how these major basins evolve during the Cenozoic. However, little has been known about the exact ages of the strata and tectonic deformation of the basin. Herein, detailed paleomagnetic and structural studies are conducted on the southern Baiquanhe section in the central Kumkol basin, northern Tibetan Plateau. The magnetostratigraphic study indicates that the southern Baiquanhe section spans a time interval of 8.2-4.2 Ma. Well-preserved growth strata date to 7.5 Ma, providing evidence for a significant thrust fault-related folding. This thrust-related folding has also been identified in the Tian Shan foreland and in the northern Tibetan Plateau, most likely implying a pulsed basinward deformation during the late Miocene.

  9. Crustal structure of the Western Carpathians and Pannonian Basin System: seismic models from CELEBRATION 2000 data and geological implication

    Science.gov (United States)

    Janik, Tomasz; Grad, Marek; Guterch, Aleksander; Vozár, Jozef; Bielik, Miroslav; Vozárova, Anna; Hegedżs, Endre; Attila Kovács, Csaba; Kovács, István.; Celebration 2000 Working Group

    2010-05-01

    During CELEBRATION 2000 experiment the area of the Western Carphathians and Pannonian Basin System on the territory of southeastern Poland, Slovak Republic and Hungary was investigated by dense system of the deep seismic sounding profiles. In this paper, we present results of modelling of refracted and reflected waves with use 2-D ray tracing technique for profiles CEL01, CEL04, CEL05, CEL06, CEL11, CEL12 and CEL28. All seven profiles were jointly interpreted with verification and control the models at crossing points. Obtained P-wave velocity models of the crust and uppermost mantle are very complex and show differentiation of the seismic structure, where the depth of the Moho discontinuity is changing from about 25 to about 45 km. In the southern part of the area the relatively thin Pannonian Basin System crust consists of 3-7 km thick sediments and two crustal layers with 5.9-6.3 km/s in the upper crust and 6.3-6.6 km/s in the lower crust. In the upper crust of ALCAPA beneath profile CEL05 a high velocity body of Vp≥ 6.4 km/s was detected in the uppermost 5 km, which corresponds to the Bükk Composite Terrane. The total thickness of the ALCAPA crust is 1-2 km bigger than in the Tisza-Dacia. In the northern part of the area we observe 10-20 km thick uppermost crust with low velocity (Vp≤6.0 km/s), connected with TESZ and Carpathian Foredeep. Together with ca. 6.2-6.5 km/s and 6.5-6.9 km/s crustal layers they have a total thickness of 30-45 km (north of the Pieniny Klippen Belt). A sub-Moho velocities have in average values of 7.8-8.0 km/s for the Pannonian basin System, while in the Western Carpathian, the Trans-European suture zone (TESZ) and the East European Craton (EEC) part they are slightly bigger, 8.0-8.1 km/s. Lower velocities beneath the microplates ALCAPA and Tisza-Dacia could be caused by the different mineralogical and petrological compositions and the significant higher surface heat flow and temperature within the upper mantle. Beneath some

  10. Shallow Miocene basaltic magma reservoirs in the Bahia de Los Angeles basin, Baja California, Mexico

    Science.gov (United States)

    Delgado-Argote, Luis A.; García-Abdeslem, Juan

    1999-01-01

    The basement in the Bahía de Los Angeles basin consists of Paleozoic metamorphic rocks and Cretaceous granitoids. The Neogene stratigraphy overlying the basement is formed, from the base to the top, by andesitic lava flows and plugs, sandstone and conglomeratic horizons, and Miocene pyroclastic flow units and basaltic flows. Basaltic dikes also intrude the whole section. To further define its structure, a detailed gravimetric survey was conducted across the basin about 1 km north of the Sierra Las Flores. In spite of the rough and lineal topography along the foothills of the Sierra La Libertad, we found no evidence for large-scale faulting. Gravity data indicates that the basin has a maximum depth of 120 m in the Valle Las Tinajas and averages 75 m along the gravimetric profile. High density bodies below the northern part of the Sierra Las Flores and Valle Las Tinajas are interpreted to be part of basaltic dikes. The intrusive body located north of the Sierra Las Flores is 2.5 km wide and its top is about 500 m deep. The lava flows of the top of the Sierra Las Flores, together with the distribution of basaltic activity north of this sierra, suggests that this intrusive body continues for 20 km along a NNW-trending strike. Between the sierras Las Flores and Las Animas, a 0.5-km-wide, 300-m-thick intrusive body is interpreted at a depth of about 100 m. This dike could be part of the basaltic activity of the Cerro Las Tinajas and the small mounds along the foothills of western Sierra Las Animas. The observed local normal faulting in the basin is inferred to be mostly associated with the emplacement of the shallow magma reservoirs below Las Flores and Las Tinajas.

  11. Strike-slip pull-apart process and emplacement of Xiangshan uranium-producing volcanic basin

    International Nuclear Information System (INIS)

    Qiu Aijin; Guo Lingzhi; Shu Liangshu

    2001-01-01

    Xiangshan volcanic basin is one of the famous uranium-producing volcanic basins in China. Emplacement mechanism of Xiangshan uranium-producing volcanic basin is discussed on the basis of the latest research achievements of deep geology in Xiangshan area and the theory of continental dynamics. The study shows that volcanic activity in Xiangshan volcanic basin may be divided into two cycles, and its emplacement is controlled by strike-ship pull-apart process originated from the deep regional faults. Volcanic apparatus in the first cycle was emplaced in EW-trending structure activated by clockwise strike-slipping of NE-trending deep fault, forming the EW-trending fissure-type volcanic effusion belt. Volcanic apparatus in the second cycle was emplaced at junction points of SN-trending pull-apart structure activated by sinistral strike-slipping of NE-trending deep faults and EW-trending basement faults causing the center-type volcanic magma effusion and extrusion. Moreover, the formation mechanism of large-rich uranium deposits is discussed as well

  12. Heat Flow Variation along the Nankai Trough Floor Correlated with the Structure of the Shikoku Basin Oceanic Crust

    Science.gov (United States)

    Yamano, M.; Kawada, Y.; Gao, X.

    2016-12-01

    Surface heat flow observed on the floor of the Nankai Trough, near the trench axis, is highly variable and does not well correspond to the seafloor age of the incoming Philippine Sea plate (Shikoku Basin). Recent detailed measurements between 133.5°E and 137°E revealed that heat flow on the trough floor significantly varies along the trough. The most conspicuous variation is found around 136°E. Heat flow is extremely high and variable between 135°E and 136°E, much higher than the value estimated from the age. On the east of 136°E, heat flow gradually decreases eastward over 50 km to the value nearly consistent with the age with no appreciable scatter. Elevated heat flow on the trough floor can be attributed to vigorous fluid circulation in a permeable layer (aquifer) in the subducted oceanic crust, which efficiently transports heat upward along the plate interface (Spinelli and Wang, 2008). The heat flow variation around 136°E may therefore arise from variation in the permeability structure of the crustal aquifer. A probable cause of the heterogeneity in the aquifer permeability is a structure boundary in the incoming Shikoku Basin, the boundary between the younger part on the west formed by spreading in NE-SW direction and the older part on the east formed by E-W spreading. It is located around 136°E, about the same place as the heat flow distribution boundary. A possible additional source of variation in the permeability structure is the geometry of the subducted Philippine Sea plate. A prominent bend in the subducted plate between 135°E and 136°E, which corresponds to the high heat flow area on the trough floor, may have fractured the oceanic crust and enhanced the aquifer permeability. We evaluated the influence of variations in the aquifer permeability on the thermal structure through 3D numerical modelling using a high thermal-conductivity proxy for heat transport by fluid flow. A sharp along-strike change in the permeability of the subducted

  13. BENTHIC MACROINVERTEBRATE COMMUNITY STRUCTURE IN THE UPPER HYDROGRAPHIC BASIN OF CERNA RIVER IN RELATION TO WATER QUALITY (WEST AND SOUTH-WESTERN ROMANIA

    Directory of Open Access Journals (Sweden)

    CORINA TUDORESCU

    2009-01-01

    Full Text Available The quality of an hydrographic basin may be reflected by the composition of benthic macroinvertebrates communities as they can be influenced by the quality degradations of physical and chemical water parameters. The structure of the benthic community in the upper basin of the Cerna river was characterized by the presence of 13 groups. Abundance and frequency values recorded for benthic communities varied according to the physical-chemical conditions specific to each sample collecting station. Plecoptera, Ephemeroptera, Trichoptera and Amphipoda were influenced by changes in water quality, changes that were reflected in the composition and structure of such communities with low levels of abundance, reaching extinction in some areas of the basin.

  14. A documentation of structures in unconsolidated sediments along the north shore of the Minas Basin, Nova Scotia

    International Nuclear Information System (INIS)

    Stokes, T.R.

    1988-12-01

    During the summer of 1987 the north shore of the Minas Basin, Nova Scotia, was examined for evidence of structures in unconsolidated sediments. This shoreline exposes the eastern extension of the Cobequid-Chedabucto fault system which was active from the Devonian until at least the Permian, and possible into the Mesozoic. The primary aim of the study was to document, measure and record any structures in unconsolidated sediments. In all, thirty-four structure locations were found; of these, twenty-nine were in glacial outwash deltas, the results of the Late Wisconsinan ice retreat. The most important structures include: 1) conjugate normal faults in Advocate Harbour sands and muds at East Finney Brook; 2) associated faults and folds in the Advocate Harbour bottomset muds at Lower Five Islands; and 3) major convolutions in Advocate Harbour bottomset muds at Economy Point. The convolutions are the results of seismic shaking which either postdated delta formation or triggered synsedimentary slumping. The faults and folds at Lower Five Islands were formed by extension related to either delta slumping or possible bedrock movement. The conjugate fault set at East Finney Brook is the result of an extensional event probably caused by late NE-SW normal fault reactivation. It is unclear whether this reactivation is the result of glacial rebound or neotectonic movement

  15. Arc Boudinage, Basin Inversion and Obduction in an Evolving Subduction System of East Antarctica

    Science.gov (United States)

    Ferraccioli, F.; Balbi, P.; Armadillo, E.; Crispini, L.; Capponi, G.

    2014-12-01

    The paleo-Pacific margin of Gondwana experienced protracted subduction and accretionary tectonics starting in late Neoproterozic-early Cambrian times. Northern Victoria Land (NVL), in East Antarctica, preserves a cryptic record of these active margin processes. Most models indicate that NVL contains three main terranes, namely the Robertson Bay, Bowers and Wilson terranes. Significant debate centres, however, on whether these are far travelled terranes with respect to the East Antarctic Craton, and on the tectonic and magmatic processes that affected its active margin and were ultimately responsible for the formation of the Ross Orogen. Here we interpret new aeromagnetic, aerogravity and land-gravity compilations that enable us to trace the extent of major subglacial faults in the basement of NVL, examine crustal architecture, and propose a new evolutionary model for the active margin of the craton. Prominent aeromagnetic anomalies at the edge of the Wilkes Subglacial Basin delineate the extent of an early-stage magmatic arc (ca 530 Ma?). This arc may have accreted as an exotic element onto the former Neoproterozoic rifted margin of East Antarctica or (perhaps more likely) developed in situ upon a pre-existing suture. Remnants of magnetic arc basement are also identified ca 150 km further to the east within the Wilson Terrane (WT). We propose that these were originally adjacent arc segments and that transtension triggered significant arc boudinage separating these segments. Transtension may have created accommodation space for the development of thick Cambrian sedimentary basins, which are marked by regional magnetic lows with an en-echelon geometry. Basin inversion likely occurred in a later traspressional stage of the Ross-Delamerian Orogen (ca. 490-460 Ma) that triggered the development of a major pop-up structure within the WT. Several buried thrusts of the pop-up can be traced in the aeromagnetic images and a prominent residual gravity high delineates its high

  16. A study of structural lineaments in Pantanal (Brazil) using remote sensing data.

    Science.gov (United States)

    Paranhos Filho, Antonio C; Nummer, Alexis R; Albrez, Edilce A; Ribeiro, Alisson A; Machado, Rômulo

    2013-09-01

    This paper presents a study of the structural lineaments of the Pantanal extracted visually from satellite images (CBERS-2B satellite, Wide Field Imager sensor, a free image available in INTERNET) and a comparison with the structural lineaments of Precambrian and Paleozoic rocks surrounding the Cenozoic Pantanal Basin. Using a free software for satellite image analysis, the photointerpretation showed that the NS, NE and NW directions observed on the Pantanal satellite images are the same recorded in the older rocks surrounding the basin, suggesting reactivation of these basement structural directions during the Quaternary. So the Pantanal Basin has an active tectonics and its evolution seems to be linked to changes that occurred during the Andean subduction.

  17. Population genetic structuring in pacu (Piaractus mesopotamicus across the Paraná-Paraguay basin: evidence from microsatellites

    Directory of Open Access Journals (Sweden)

    Daniela Calcagnotto

    Full Text Available The Paraná-Paraguay basin encompasses central western Brazil, northeastern Paraguay, eastern Bolivia and northern Argentina. The Pantanal is a flooded plain with marked dry and rainy seasons that, due to its soil characteristics and low declivity, has a great water holding capacity supporting abundant fish fauna. Piaractus mesopotamicus, or pacu, endemic of the Paraná-Paraguay basin, is a migratory species economically important in fisheries and ecologically as a potential seed disperser. In this paper we employ eight microsatellite loci to assess the population structure of 120 pacu sampled inside and outside the Pantanal of Mato Grosso. Our main objective was to test the null hypothesis of panmixia and to verify if there was a different structuring pattern between the Pantanal were there were no physical barriers to fish movement and the heavily impounded Paraná and Paranapanema rivers. All loci had moderate to high levels of polymorphism, the number of alleles varied from three to 18. The average observed heterozygosity varied from 0.068 to 0.911. After the Bonferroni correction three loci remained significant for deviations from Hardy-Weinberg, and for those the frequency of null alleles was estimated. F ST and R ST pairwise comparisons detected low divergence among sampling sites, and differentiation was significant only between Paranapanema and Cuiabá and Paranapanema and Taquari. No correlation between genetic distance and the natural logarithm of the geographic distance was detected. Results indicate that for conservation purposes and for restoration programs small genetic differences detected in the Cuiabá and Paranapanema rivers should be taken in consideration.

  18. Basement membrane proteoglycans in glomerular morphogenesis: chondroitin sulfate proteoglycan is temporally and spatially restricted during development

    DEFF Research Database (Denmark)

    McCarthy, K J; Bynum, K; St John, P L

    1993-01-01

    basement membrane (GBM) but present in other basement membranes of the nephron, including collecting ducts, tubules, Bowman's capsule, and the glomerular mesangium. In light of this unique pattern of distribution and of the complex histoarchitectural reorganization occurring during nephrogenesis...

  19. Increasingly transformed MCF-10A cells have a progressively tumor-like phenotype in three-dimensional basement membrane culture

    Directory of Open Access Journals (Sweden)

    Imbalzano Anthony N

    2009-03-01

    Full Text Available Abstract Background MCF-10A cells are near diploid and normal human mammary epithelial cells. In three-dimensional reconstituted basement membrane culture, they undergo a well-defined program of proliferation, differentiation, and growth arrest, forming acinar structures that recapitulate many aspects of mammary architecture in vivo. The pre-malignant MCF-10AT cells and malignant MCF-10CA1a lines were sequentially derived from the MCF-10A parental cell line first by expression of a constitutively active T24 H-Ras generating the MCF-10AT cell line. This was followed by repeated selection for increasingly aggressive tumor formation from cells recovered from xenograft tumors in immuno-compromised mice, generating the MCF-10CA1a cell line. When inoculated subcutaneously into the flanks of immuno-compromised mice, MCF-10AT cells occasionally form tumors, whereas MCF-10CA1a cells invariably form tumors with a shorter latency than MCF-10AT derived tumors. Results MCF-10AT cells grown in three-dimensional basement membrane culture form complex multi-acinar structures that produce a basement membrane but undergo delayed cell cycle arrest and have incomplete luminal development. MCF-10CA1a cells grown in three-dimensional basement membrane culture form large, hyper-proliferative masses, that retain few characteristics of MCF10A acini and more closely resemble tumors. Conclusion Here we report on the growth and differentiation properties of these three matched cell lines in three-dimensional basement membrane culture. Features of tissue morphogenesis were assessed, including proliferation, basement membrane formation, polarization of alpha-6 beta-4 integrin to the basement membrane, formation of cell:cell junctions, and apoptosis for luminal clearance. The matched series of normal MCF-10A, pre-malignant MCF-10AT, and malignant MCF-10CA1a cells offers a unique opportunity to study the mechanisms of malignant progression both in a three

  20. Deformation History of the Haymana Basin: Structural Records of Closure-Collision and Subsequent Convergence (Indentation) Events at the North-Central Neotethys (Central Anatolia, Turkey)

    Science.gov (United States)

    Gülyüz, Erhan; Özkaptan, Murat; Kaymakcı, Nuretdin

    2016-04-01

    Gondwana- (Tauride Platfrom and Kırşehir Block) and Eurasia (Pontides) - derived continental blocks bound the Haymana basin, in the south and north, respectively. Boundaries between these blocks are signed by İzmir-Ankara-Erzincan and debatable Intra-Tauride Suture zones which are straddled by the Haymana Basin in the region. In this regard, deformation recorded in the upper Cretaceous to middle Eocene deposits of the basin is mainly controlled by the relative movements of these blocks. Therefore, understanding the structural evolution of the Haymana Basin in a spatio-temporal concept is crucial to shed some light on some debatable issues such as ; (1) timing of late stage subduction histories of various branches of Neotethys and subsequent collision events, (2) effects of post-collisional tectonic activity in the Haymana region. Fault kinematic analyses (based on 623 fault-slip data from 73 stations) indicate that the basin was subjected to initially N-S to NNE-SSW extension until middle Paleocene and then N-S- to NNE-SSW- directed continuous compression and coeval E-W to ESE-WNW extension up to middle Miocene. These different deformation phases correspond to the fore-arc (closure) and foreland (collision and further convergence) stages of the basin. Additionally, fold analyses (based on 1017 bedding attitudes) and structural mapping studies show that development of folds and major faults are coeval and they can be explained by principle stress orientations of the second deformation phase. The Haymana basin is, based on the trends of E-W- and WNW-ESE- directed structures at the south-eastern and the north-western parts of the basin, respectively, divided into two structural segments. The balanced cross-sections also indicate ~4% and ~25% shortening at the north-western and south-eastern segments, respectively. The differences in amounts of shortenings are explained by reduce in effectiveness zone of basin-bounding thrust faults towards west. On the other hand

  1. Hydrogeological evolution of the Luni river basin, Rajasthan ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    regional depression is indicated in the basement, which is coincident with the tributary streams of. Luni system. ... ure 4) there is a depression filled with alluvium. Towards the west and central part of the basin, depth to ...... culture is on the braided river bed in valley fill area formed by dissected pediments. Four windows,.

  2. Morphometric Analysis of Ogunpa and Ogbere Drainage Basins ...

    African Journals Online (AJOL)

    The paper analysed the morphometric parameters of Ogbere and Ogunpa drainage basins located on basement complex rock in Southwestern Nigeria. Data used were generated from topographi