Nd isotopes, U-Pb single grain and SHRIMP zircon ages from basement rocks of the Tocantin Province

International Nuclear Information System (INIS)

Fuck, R.A.; Dantas, E.L.; Pimentel, M.M.; Junges, S.L.; Moraes, R

2001-01-01

Large areas of the northern part of the Brasilia Belt, Tocantins Province, central Brazil, are underlain by basement granite-gneiss terrain and associated volcano-sedimentary sequences, as well as felsic and mafic-ultramafic intrusions. The basement rocks are covered by the late Paleoproterozoic-Mesoproterozoic rift-related Arai and Natividade groups and intruded by 1.77 to 1.58 Ga an orogenic granites of the Goias Tin Province (Pimentel and Botelho, 2001). To the southwest they are un conformably overlain by the low-grade late Proterozoic Paranoa Group, whereas to the east they are in faulted contact with the Neoproterozoic Bambui Group at the western edge of the Sao Francisco Craton. To the north they are covered by Phanerozoic sediments of the Parnaiba and Sanfranciscana basins. Despite their large extension, granite-gneiss and associated supracrustals of SE Tocantins and NE Goias are still poorly known. Previous regional Rb-Sr and K-Ar isotopic studies indicated dominant early Proterozoic ages and late Proterozoic cooling ages (Hasui, et al. 1980, Fernandes et al. 1982). More detailed studies in the Almas-Dianopolis area (Costa, 1984) came up with similar results, although the region was interpreted as underlain by Archean granite-greenstone terrain, following previous suggestions by Costa et al. (1976). Recent work recognized the presence of two suites of deformed granitoids (Cruz and Kuyumjian, 1996, 1998). The oldest suite intruded the supracrustals and comprises hornblende-bearing tonalite gneiss, with minor trondhjemite, granodiorite, and quartz diorite. The younger suite comprises oval shaped biotite-bearing tonalite, trondhjemite, and granodiorite intrusions. Both suites display low-K calc-alkaline affinity, the younger being more Al-rich. Both are interpreted as TTG suites and were dated at 2,2 Ga using U-Pb SHRIMP (Cruz et al 2000). In the Porto Nacional area, Gorayeb et al. (2000) determined single zircon Pb-evaporation ages of 2.15 Ga in granulites

Correlation of basement rocks from Waka Nui-1 and Awhitu-1, and the Jurassic regional geology of Zealandia

International Nuclear Information System (INIS)

Mortimer, N.; Raine, J.I.; Cook, R.A.

2009-01-01

Core and cuttings of sandstone and mudstone from Waka Nui-1, an offshore oil exploration well west of Northland, and from Awhitu-1, a water bore in western Auckland, add to the growing number of samples retrieved from otherwise inaccessible basement of the Zealandia continent. On the basis of pollen and spores, the sedimentary rocks at the bottom of Waka Nui-1 are dated as Early-Middle Jurassic, and rocks from Awhitu-1 are Late Jurassic. On the basis of age, sandstone petrology, and geographic position, a correlation of rocks in both wells with Murihiku Terrane is probable. In New Zealand, Jurassic sedimentary rocks have usually been interpreted in a tectonostratigraphic terrane context. An alternative way to look at the New Zealand Late Jurassic to Early Cretaceous sedimentary rocks is as potentially interconnected forearc, intra-arc, back-arc, and intracontinental basins that evolved adjacent to an active margin. (author). 47 refs., 6 figs., 3 tabs

Rb/Sr and U/Pb isotopic ages in basement rocks of Mina Gonzalito and Arroyo Salado, Atlantic North-Patagonian Massif, Rio Negro, Argentina

International Nuclear Information System (INIS)

Varela, Ricardo; Sato, Ana M.; Cingolani, Carlos A.; Basei, Miguel A.S.; Siga, Oswaldo; Sato, Kei

1998-01-01

Isotopic ages from metamorphic and plutonic rocks of the Atlantic area of North Patagonian basement indicate that the main crustal tectonic events occurred during the late Proterozoic to early Paleozoic times. Rb/Sr and U/Pb data in the 550-470 Ma interval suggest an old tecto-thermal activity during the upper Brazilian Cycle (Rio Doce Orogeny). At regional scale, the comparable Neo proterozoic basement of Ventania and sedimentary for eland cover of Tandilia continues to the Northeast, in the Dom Feliciano Belt. A possible correlation of the North Patagonian basement with igneous-metamorphic relics of Central Argentina (Pampean Ranges of San Luis-Cordoba and at La Pampa province) is also indicated. (author)

Assessing the geo-electric characteristics of Basement Complex rocks and its implication for groundwater prospecting in Ilorin Metropolis, Nigeria

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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.

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

The metamorphic basement of the Cordillera Frontal of Mendoza: New geochronologic and isotopic data

International Nuclear Information System (INIS)

Basei, Miguel; Ramos, Victor A.; Vujovich, Graciela I.; Poma, Stella

1998-01-01

The metamorphic rocks of the Cordillera Frontal exposed in the Cordon del Portillo, Mendoza were examined by Rb/Sr geochronology and Nd/Sm isotopic analysis. The Rb/Sr data defined a Devonian age for the last metamorphic episode, similar to the previous K/Ar and Ar/Ar ages obtained in this region and western Precordillera. The isotopic analysis identified three sets of model ages: 1.- The oldest corresponds to a set of meta sedimentary rocks with a model age of 1,400 to 1,700 Ma; 2.- A monzogranodiorite with a model age of 1,000 Ma; and 3.- Metabasites with model ages between 577 and 330 Ma. These rocks are interpreted as 1.- A typical Grenvillian derived basement; 2.- Late Paleozoic granitoids derived from a different Proterozoic basement; and 3.- Some Eopaleozoic metabasites tectonically inter fingered with the Grenvillian basement. These new data are coherent with the existence of a Laurentia derived terrane, Chilenia, that was separated by oceanic rocks from the basement of Pre cordillera during Eopaleozoic times. This last basement known as the Cuyania terrane, was also derived from Laurentia. (author)

Basement Surface Faulting and Topography for Savannah River Site and Vicinity

International Nuclear Information System (INIS)

Cumbest, R.J.

1998-01-01

This report integrates the data from more than 60 basement borings and over 100 miles of seismic reflection profiling acquired on the Savannah River Site to map the topography of the basement (unweathered rock) surface and faulting recorded on this surface

Geology of the Pan-African basement Complex in Ube-Wulko area ...

African Journals Online (AJOL)

The Ube-Wulko area of southeast Akwanga falls within the Pan-African remobilized Basement Complex of northcentral Nigeria. It consists of intensely multi-deformed high grade polymetamorphic basement rocks, predominantly composed of migmatitic gneisses and schists and subordinate quartzites, marbles, and ...

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 ...

SHRIMP zircon dating and LA-ICPMS Hf analysis of early Precambrian rocks from drill holes into the basement beneath the Central Hebei Basin, North China Craton

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Yusheng Wan

2014-07-01

Full Text Available The Central Hebei Basin (CHB is one of the largest sedimentary basins in the North China Craton, extending in a northeast–southwest direction with an area of >350 km2. We carried out SHRIMP zircon dating, Hf-in-zircon isotopic analysis and a whole-rock geochemical study on igneous and metasedimentary rocks recovered from drill holes that penetrated into the basement of the CHB. Two samples of gneissic granodiorite (XG1-1 and gneissic quartz diorite (J48-1 have magmatic ages of 2500 and 2496 Ma, respectively. Their zircons also record metamorphic ages of 2.41–2.51 and ∼2.5 Ga, respectively. Compared with the gneissic granodiorite, the gneissic quartz diorite has higher ΣREE contents and lower Eu/Eu* and (La/Ybn values. Two metasedimentary samples (MG1, H5 mainly contain ∼2.5 Ga detrital zircons as well as late Paleoproterozoic metamorphic grains. The zircons of different origins have εHf (2.5 Ga values and Hf crustal model ages ranging from 0 to 5 and 2.7 to 2.9 Ga, respectively. Therefore, ∼2.5 Ga magmatic and Paleoproterozoic metasedimentary rocks and late Neoarchean to early Paleoproterozoic and late Paleoproterozoic tectono-thermal events have been identified in the basement beneath the CHB. Based on regional comparisons, we conclude that the early Precambrian basement beneath the CHB is part of the North China Craton.

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

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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.

Seismic evidence of exhumed mantle rock basement at the Gorringe Bank and the adjacent Horseshoe and Tagus abyssal plains (SW Iberia)

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Sallarès, Valentí; Martínez-Loriente, Sara; Prada, Manel; Gràcia, Eulàlia; Ranero, César; Gutscher, Marc-André; Bartolome, Rafael; Gailler, Audrey; Dañobeitia, Juan José; Zitellini, Nevio

2013-03-01

The Gorringe Bank is a gigantic seamount that separates the Horseshoe and Tagus abyssal plains offshore SW Iberia, in a zone that hosts the convergent boundary between the Africa and Eurasia plates. Although the region has been the focus of numerous investigations since the early 1970s, the lack of appropriate geophysical data makes the nature of the basement, and thus the origin of the structures, still debated. In this work, we present combined P-wave seismic velocity and gravity models along a transect that crosses the Gorringe Bank from the Tagus to the Horseshoe abyssal plains. The P-wave velocity structure of the basement is similar in the Tagus and Horseshoe plains. It shows a 2.5-3.0 km-thick top layer with a velocity gradient twice stronger than oceanic Layer 2 and an abrupt change to an underlying layer with a five-fold weaker gradient. Velocity and density is lower beneath the Gorringe Bank probably due to enhanced fracturing, that have led to rock disaggregation in the sediment-starved northern flank. In contrast to previous velocity models of this region, there is no evidence of a sharp crust-mantle boundary in any of the record sections. The modelling results indicate that the sediment overlays directly serpentinite rock, exhumed from the mantle with a degree of serpentinization decreasing from a maximum of 70-80% under the top of Gorringe Bank to less than 5% at a depth of ˜20 km. We propose that the three domains were originally part of a single serpentine rock band, of nature and possibly origin similar to the Iberia Abyssal Plain ocean-continent transition, which was probably generated during the earliest phase of the North Atlantic opening that followed continental crust breakup (Early Cretaceous). During the Miocene, the NW-SE trending Eurasia-Africa convergence resulted in thrusting of the southeastern segment of the exhumed serpentinite band over the northwestern one, forming the Gorringe Bank. The local deformation associated to plate

Polymetamorphic evolution of the granulite-facies Paleoproterozoic basement of the Kabul Block, Afghanistan

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Collett, Stephen; Faryad, Shah Wali; Mosazai, Amir Mohammad

2015-08-01

The Kabul Block is an elongate crustal fragment which cuts across the Afghan Central Blocks, adjoining the Indian and Eurasian continents. Bounded by major strike slip faults and ophiolitic material thrust onto either side, the block contains a strongly metamorphosed basement consisting of some of the only quantifiably Proterozoic rocks south of the Herat-Panjshir Suture Zone. The basement rocks crop-out extensively in the vicinity of Kabul City and consist predominantly of migmatites, gneisses, schists and small amounts of higher-grade granulite-facies rocks. Granulite-facies assemblages were identified in felsic and mafic siliceous rocks as well as impure carbonates. Granulite-facies conditions are recorded by the presence of orthopyroxene overgrowing biotite in felsic rocks; by orthopyroxene overgrowing amphibole in mafic rocks and by the presence of olivine and clinohumite in the marbles. The granulite-facies assemblages are overprinted by a younger amphibolite-facies event that is characterized by the growth of garnet at the expense of the granulite-facies phases. Pressure-temperature (P-T) conditions for the granulite-facies event of around 850 °C and up to 7 kbar were calculated through conventional thermobarometry and phase equilibria modeling. The younger, amphibolite-facies event shows moderately higher pressures of up to 8.5 kbar at around 600 °C. This metamorphism likely corresponds to the dominant metamorphic event within the basement of the Kabul Block. The results of this work are combined with the litho-stratigraphic relations and recent geochronological dating to analyze envisaged Paleoproterozoic and Neoproterozoic metamorphic events in the Kabul Block.

Rock Magnetic Study of IODP/ICDP Expedition 364 Site M0077A Drill Cores: Post-Impact Sediments, Impact Breccias, Melt, Granitic Basement and Dikes

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Fucugauchi, J. U.; Perez-Cruz, L. L.; Rebolledo-Vieyra, M.; Tikoo, S.; Zylberman, W.; Lofi, J.

2017-12-01

Drilling at Site M0077 sampled post-impact sediments overlying a peak ring consisting of impact breccias, melt rock and granitoids. Here we focus on characterizing the peak ring using magnetic properties, which vary widely and depend on mineralogy, depositional and emplacement conditions and secondary alterations. Rock magnetic properties are integrated with Multi-Sensor Core Logger (MSCL) data, vertical seismic profile, physical properties, petrographic and chemical analyses and geophysical models. We measure low-field magnetic susceptibility at low- and high-frequencies, intensity and direction of natural remanent magnetization (NRM) and laboratory-induced isothermal (IRM) and anhysteretic (ARM) magnetizations, alternating-field demagnetization of NRM, IRM and NRM, susceptibility variation with temperature, anisotropy of magnetic susceptibility, hysteresis and IRM back-field demagnetization. Post-impact carbonates show low susceptibilities and NRM intensities, variable frequency-dependent susceptibilities and multivectorial remanences residing in low and high coercivity minerals. Hysteresis loops show low coercivity saturation magnetizations and variable paramagnetic mineral contents. Impact breccias (suevites) and melt rock show higher susceptibilities, low frequency-dependent susceptibilities, high NRM, ARM and IRM intensities and moderate ARM intensity/susceptibility ratios. Magnetic signal is dominated by fine-grained magnetite and titanomagnetites with PSD domain states. Melt rocks at the base of impactite section show the highest susceptibilities and remanence intensities. Basement section is characterized by low susceptibilities in the granites and higher values in the dikes, with NRM and ARM intensities increasing towards the base. The high susceptibilities and remanence intensities correlate with high seismic velocities, density and decreased porosity and electrical resistivity. Fracturing and alteration account for the reduced seismic velocities

Pre-Cenozoic basement rocks of the Proto-Philippine Sea Plate: Constraints for the birthplace of the Izu-Bonin-Mariana Arc

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Tani, K.; Ishizuka, O.; Horie, K.; Barth, A. P.; Harigane, Y.; Ueda, H.

2016-12-01

The Izu-Bonin-Mariana Arc is widely regarded to be a typical intra-oceanic arc, with the oceanic Pacific Plate subducting beneath the Philippine Sea Plate, an evolving complex of active and inactive arcs and back-arc basins. However, little is known about the origin of the proto-Philippine Sea Plate, which existed along with the Pacific Plate at the time of subduction initiation in the Eocene. To investigate the crustal structures of the proto-Philippine Sea Plate, we conducted manned-submersible and dredge surveys in the Daito Ridges and the Kyushu-Palau Ridge. The Daito Ridges comprise the northwestern Philippine Sea Plate along with what are regarded as remnants of the proto-Philippine Sea Plate. Submersible observations and rock sampling revealed that the Daito Ridges expose deep crustal sections of gabbroic, granitic, metamorphic, and ultra-mafic rocks, along with volcanic rocks ranging from basalt to andesite. Mesozoic magmatic zircon U-Pb ages have been obtained from the plutonic rocks, and whole-rock geochemistry of the igneous rocks indicates arc origins. Furthermore, mafic schist collected from the Daito Ridge has experienced amphibolite facies metamorphism, with phase assemblages suggesting that the crust was thicker than 20 km at the time. Similar amphibolite-facies metamorphic rocks with Proterozoic zircons have been recovered in the southern Kyushu-Palau Ridge, indicating that such distinctively older basement rocks exist as isolated tectonic blocks within the present Philippine Sea Plate. These finds show that the parts of the Daito Ridges and Kyushu-Palau Ridge represent developed crustal sections of the Pre-Cenozoic arc that comprises part of the proto-Philippine Sea Plate, and, together with the tectonic reconstruction of the proto-Philippine Sea Plate (Deschamps and Lallemand 2002, JGR), they suggest that subduction of the Izu-Bonin-Mariana Arc initiated at the continental margin of the Southeast Asia.

Eocene extensional exhumation of basement and arc rocks along southwesternmost Peru, Central Andes.

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Noury, Mélanie; Bernet, Matthias; Sempéré, Thierry

2014-05-01

The overthickened crust of the current Central Andes is commonly viewed as the result of tectonic shortening. However, in the present-day terrestrial forearc and arc of southwesternmost Peru, crustal thickness increases from 30 km along the coastline to >60 km below the active arc, whereas the upper crust exhibits little to no evidence of crustal shortening and, in constrast, many extensional features. How (and when) crustal overthickness was acquired in this region is thus little understood. Because crustal overthickening often results in extensional collapse and/or significant erosion, here we address this issue through a regional-scale study of exhumation using fission-track thermochronology. The limited fission-track data previously available in the area suggested that exhumation began during the Mesozoic. In this study, we present new apatite and zircon fission-track data obtained along the current terrestrial forearc of southwesternmost Peru. This relatively restricted area presents the interest of providing extensive outcrops of Precambrian to Ordovician basement and Early Jurassic to Late Cretaceous arc plutons. In order to compare the chronology of exhumation of these units, we performed extensive sampling for fission-track dating, as well as structural mapping. Our results indicate that the basement rocks and Jurassic plutons that crop out in the Arequipa region, where the crust is now >50 km-thick, experienced a rapid cooling through the 240-110°C temperature range between ~65 and ~35 Ma. This period of rapid exhumation coincided in time with the accumulation of terrestrial forearc deposits (the Lower Moquegua Group), that exhibit many syn-sedimentary extensional features and are bounded by conspicuous normal faults, specifically along the region where intense activity of the main arc between ~90 and ~60 Ma had led to voluminous magma emplacement. This close succession of (1) intense magmatic activity and (2) regional-scale exhumation associated with

Surface analogue outcrops of deep fractured basement reservoirs in extensional geological settings. Examples within active rift system (Uganda) and proximal passive margin (Morocco).

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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

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).

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.

Geoelectrical characterisation of basement aquifers: the case of Iberekodo, southwestern Nigeria

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Aizebeokhai, Ahzegbobor P.; Oyeyemi, Kehinde D.

2018-03-01

Basement aquifers, which occur within the weathered and fractured zones of crystalline bedrocks, are important groundwater resources in tropical and subtropical regions. The development of basement aquifers is complex owing to their high spatial variability. Geophysical techniques are used to obtain information about the hydrologic characteristics of the weathered and fractured zones of the crystalline basement rocks, which relates to the occurrence of groundwater in the zones. The spatial distributions of these hydrologic characteristics are then used to map the spatial variability of the basement aquifers. Thus, knowledge of the spatial variability of basement aquifers is useful in siting wells and boreholes for optimal and perennial yield. Geoelectrical resistivity is one of the most widely used geophysical methods for assessing the spatial variability of the weathered and fractured zones in groundwater exploration efforts in basement complex terrains. The presented study focuses on combining vertical electrical sounding with two-dimensional (2D) geoelectrical resistivity imaging to characterise the weathered and fractured zones in a crystalline basement complex terrain in southwestern Nigeria. The basement aquifer was delineated, and the nature, extent and spatial variability of the delineated basement aquifer were assessed based on the spatial variability of the weathered and fractured zones. The study shows that a multiple-gradient array for 2D resistivity imaging is sensitive to vertical and near-surface stratigraphic features, which have hydrological implications. The integration of resistivity sounding with 2D geoelectrical resistivity imaging is efficient and enhances near-surface characterisation in basement complex terrain.

Geology and petrography of basement in south extreme in Sierra Grande de San Luis, Argentina

International Nuclear Information System (INIS)

Morosini, A.; Ortiz Suarez, A.

2007-01-01

In the south of the Sierra de San Luis is recognized a basement composed by La Escalerilla and Los Puquios granites, accompanied by schist, mylonite s and mafic-ultramafic rocks. The schists, La Escalerilla granite and the mafic -ultramafic rocks are affected by a regional metamorphism in anphibolites facies, the two first present a N-S foliation di ping to east. The mylonite s correspond to a second event of deformation, distributed in thin belts of NNE-SSO direction and inclination to east, developed in green schist to anphibolites facies. Los Puquios granite represents the more young of the basement rocks and the intrusion was associated with a shear zone. Los Puquios granite forms dikes and small plutons cutting La Escalerilla granite and micas chits in high cortical levels

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

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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.

Uranium deposits in the Beaverlodge area, northern Saskatchewan: their relationship to the Martin Group (Proterozoic) and the underlying basement

International Nuclear Information System (INIS)

Mazimhaka, P.K.; Hendry, H.E.

1989-01-01

The rocks of the Martin Group crop out in an area 60 km by 50 km north of Lake Athabasca near Uranium City, northern Saskatchewan. This area has numerous uranium showings within a few kilometres of the unconformity below the Martin Group. Mineralization occurs in fault zones, in basement rocks and in sedimentary and volcanic rocks of the Martin Group. Martin Group sediments accumulated in alluvial fans, braided streams, and ephemeral lakes. The thickest sequence (8 km to 10 km) is preserved in the Beaverlodge area, near Uranium City. The style of sedimentation changed through time as the basin evolved from deposition of conglomeratic detritus along fault scarps to the accumulation of silt in ephemeral lakes. The uneven nature of the sub-Martin unconformity surface, the lithotype of the lowermost conglomerates and breccias (Beaverlodge Formation), and the shape of the basin fill indicate deposition in fault-controlled basins. The earliest economic uranium mineralization in the rocks of the Martin Group was epigenetic. The mineralization was coeval with that in basement rocks. Economic mineralization in basement rocks and in the lowermost formation of the Martin Group is close to the unconformity. Epigenetic uranium mineralization thus appears to have resulted from processes that were related, in time and space, to either the formation of the unconformity or the deposition of the Martin Group or both. (author). 29 refs, 5 figs

PRINCIPLE ROCK TYPES FOR RADIOACTIVE WASTE REPOSITORIES

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Sibila Borojević Šostarić

2012-07-01

Full Text Available Underground geological storage of high- and intermediate/low radioactive waste is aimed to represent a barrier between the surface environment and potentially hazardous radioactive elements. Permeability, behavior against external stresses, chemical reacatibility and absorption are the key geological parameters for the geological storage of radioactive waste. Three principal rock types were discussed and applied to the Dinarides: (1 evaporites in general, (2 shale, and (3 crystalline basement rocks. (1 Within the Dinarides, evaporite formations are located within the central part of a Carbonate platform and are inappropriate for storage. Offshore evaporites are located within diapiric structures of the central and southern part of the Adriatic Sea and are covered by thick Mesozoic to Cenozoic clastic sediment. Under very specific circumstances they can be considered as potential site locations for further investigation for the storage of low/intermediate level radioactive wast e. (2 Thick flysch type formation of shale to phyllite rocks are exposed at the basement units of the Petrova and Trgovska gora regions whereas (3 crystalline magmatic to metamorphic basement is exposed at the Moslavačka Gora and Slavonian Mts. regions. For high-level radioactive waste, basement phyllites and granites may represent the only realistic potential option in the NW Dinarides.

Where are uranium and thorium stored in the Archean basement

Energy Technology Data Exchange (ETDEWEB)

Schwinner, R

1949-01-01

The author advances a theory which makes it possible to predict where prospecting for new deposits of uranium and thorium should prove successful. According to this theory, such deposits occur chiefly where the equatorial and the meridional branches of the oldest primitive rock systems cross one another. An outline of the earth's Archean basement is included.

Hydrogeologic controls on induced seismicity in crystalline basement rocks due to fluid injection into basal reservoirs.

Science.gov (United States)

Zhang, Yipeng; Person, Mark; Rupp, John; Ellett, Kevin; Celia, Michael A; Gable, Carl W; Bowen, Brenda; Evans, James; Bandilla, Karl; Mozley, Peter; Dewers, Thomas; Elliot, Thomas

2013-01-01

A series of Mb 3.8-5.5 induced seismic events in the midcontinent region, United States, resulted from injection of fluid either into a basal sedimentary reservoir with no underlying confining unit or directly into the underlying crystalline basement complex. The earthquakes probably occurred along faults that were likely critically stressed within the crystalline basement. These faults were located at a considerable distance (up to 10 km) from the injection wells and head increases at the hypocenters were likely relatively small (∼70-150 m). We present a suite of simulations that use a simple hydrogeologic-geomechanical model to assess what hydrogeologic conditions promote or deter induced seismic events within the crystalline basement across the midcontinent. The presence of a confining unit beneath the injection reservoir horizon had the single largest effect in preventing induced seismicity within the underlying crystalline basement. For a crystalline basement having a permeability of 2 × 10(-17)  m(2) and specific storage coefficient of 10(-7) /m, injection at a rate of 5455 m(3) /d into the basal aquifer with no underlying basal seal over 10 years resulted in probable brittle failure to depths of about 0.6 km below the injection reservoir. Including a permeable (kz  = 10(-13)  m(2) ) Precambrian normal fault, located 20 m from the injection well, increased the depth of the failure region below the reservoir to 3 km. For a large permeability contrast between a Precambrian thrust fault (10(-12)  m(2) ) and the surrounding crystalline basement (10(-18)  m(2) ), the failure region can extend laterally 10 km away from the injection well. © 2013, National Ground Water Association.

Nature of the basement of the East Anatolian plateau: Implications for the lithospheric foundering processes

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Topuz, G.; Candan, O.; Zack, T.; Yılmaz, A.

2017-12-01

The East Anatolian Plateau (Turkey) is characterized by (1) an extensive volcanic-sedimentary cover of Neogene to Quaternary age, (2) crustal thicknesses of 42-50 km, and (3) an extremely thinned lithospheric mantle. Its basement beneath the young cover is thought to consist of oceanic accretionary complexes of Late Cretaceous to Oligocene age. The attenuated state of the lithospheric mantle and the causes of the young volcanism are accounted for by slab steepening and subsequent break-off. We present field geological, petrological and geochronological data on three basement inliers (Taşlıçay, Akdağ and Ilıca) in the region. These areas are made up of amphibolite- to granulite-facies rocks, comprising marble, amphibolite, metapelite, quartzite and metagranite. The granulite-facies domain is equilibrated at 0.7 GPa and 800 ˚C at 83 ± 2 Ma (2σ). The metamorphic rocks are intruded by subduction-related coeval gabbroic, quartz monzonitic to tonalitic rocks. Both the metamorphic rocks and the intrusions are tectonically overlain by ophiolitic rocks. All these crystalline rocks are unconformably overlain by lower Maastrichtien clastic rocks and reefal limestone, suggesting that the exhumation at the earth's surface and juxtaposition with ophiolitic rocks occurred by early Maastrichtien. U-Pb dating on igneous zircon from metagranite yielded a protolith age of 445 ± 10 Ma (2σ). The detrital zircons from a metaquartzite point to Neoproterozoic to Early Paleozoic provenance. All these data favor a more or less continuous continental substrate to the allochthonous ophiolitic rocks beneath the young volcanic-sedimentary cover. The metamorphism and coeval magmatism can be regarded as the middle- to lower-crustal root of the Late Cretaceous magmatic arc that developed due to northward subduction along the Bitlis-Zagros suture. The presence of a continental basement beneath the young cover requires that the loss of the lithospheric mantle from beneath the East

Major and minor elements and traces in igneous rocks from crystalline basement of Parana by X-ray fluorescence

International Nuclear Information System (INIS)

Ferreira, Ademar O.; Pecequilo, Brigitte R.S.; Scapin, Marcos A.; Salvador, Vera L.R.

2015-01-01

Major and minor components of 30 acid and basic igneous rocks (granites, syenites, riolites and a basalt) of the Parana state crystalline basement were determined by X-ray fluorescence spectrometry (WDXRF), in order to evaluate the similarity in terms of the compositional content. The corrections of interelements effects (absorption/intensification) were performed by means of the fundamental parameters (FP) method. The methodology was validated using a certificated reference material. The main oxides found associated with the quantified elements are SiO_2, Al_2O_3, Na_2O, K_2O, Fe_2O_3, CaO, MgO, TiO_2, P_2O_5, MnO, SO_3, NiO, ZnO, Rb_2O. Through statistical analysis, the studied samples were organized in 3 groups of similar compositions: syenites, light granites and basalt and dark granites. The results show that the WDXRF technique is a robust tool that enables distinction even between similar geological samples. (author)

Successive hydrothermal events as indicated by oxygen isotope composition and petrography of greywacke basement rocks, Kawerau geothermal field, New Zealand

International Nuclear Information System (INIS)

Absar, A.; Blattner, P.

1985-01-01

Fifteen drillholes at the Kawerau geothermal field penetrated a sequence of Quaternary volcanic rocks overlying Mesozoic greywackes and argillites in the depth range of 650 to 1220 m below sea level. Maximum temperature in the basement is 250 to 303 deg. C. Twelve greywacke cores were modally analysed in order to determine their intensity of alteration, which in turn was compared with their oxygen isotope composition. It is concluded that Kawerau geothermal field has experienced at least three hydrothermal regimes. The earliest was characterised by fluids with low m CO 2 and δ 18 O, as indicated by the wairakite-prehnite mineral assemblage in greywacke depleted by 5 ppm. This regime was followed by a period of hydraulic fracturing the formation of a mineral assemblage with abundant calcite indicative of fluids with high dissolved CO 2 . Precipitation of minerals during these two early successive hydrothermal regimes resulted in sealing of fractures in the southern part of the field. These two mineral assemblages are indicated to have formed prior to faulting. The latest mineral assemblage comprising quartz-calcite-adularia-calc silicates on the other hand, is related to a series of NE trending faults which enabled geothermal fluids to move northeastward after circulation was precluded in the southern part. This suggests that future exploration for production from the greywacke basement should be in the north where mineralogy and δ 18 O composition of calcite indicate that much better permeability occurs

Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville-B core, Chesapeake Bay impact structure

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Townsend, Gabrielle N.; Gibson, Roger L.; Horton, J. Wright; Reimold, Wolf Uwe; Schmitt, Ralf T.; Bartosova, Katerina

2009-01-01

The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ± fibrolite ± garnet ± tourmaline ± pyrite ± rutile ± pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite-K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase-quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ± biotite ± garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ± muscovite ± pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ± epidote ± amphibole. The lower basement-derived section and both megablocks exhibit similar middle- to upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafic source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites.

Petrology, geochemistry and LA-ICP-MS U-Pb geochronology of Paleoproterozoic basement rocks in Bangladesh: An evaluation of calc-alkaline magmatism and implication for Columbia supercontinent amalgamation

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Hossain, Ismail; Tsunogae, Toshiaki; Tsutsumi, Yukiyasu; Takahashi, Kazuki

2018-05-01

The Paleoproterozoic (1.7 Ga) basement rocks from Maddhapara, Bangladesh show a large range of chemical variations (e.g. SiO2 = 50.7-74.7%) and include diorite, quartz diorite, monzodiorite, quartz monzonite and granite. The pluton overall displays metaluminous, calc-alkaline orogenic suite; mostly I-type suites formed within subduction-related magmatism. The observed major elements show general trends for fractional crystallization. Trace element contents also indicate the possibility of a fractionation or assimilation; explain the entire variation from diorite to monzonite, even granite. The pluton may have evolved the unique chemical features by a process that included partial melting of calc-alkaline lithologies and mixing of mantle-derived magmas, followed by fractional crystallization, and by assimilation of country rocks. The pluton shows evidence of crystal fractionation involving largely plagioclase, amphibole and possibly biotite. Some of the fractionated magmas may have mixed with more potassic melts from distinct parts of the continental lithosphere to produce granites and/or pegmatites. New geochronological results of granitic pegmatite (1722 ± 10 Ma) are indisputably consistent with diorite and tonalite and those data showing credible geochronological sequence (i.e., diorite - tonalite - granitic pegmatite). Identical Paleoproterozoic age (1.7 Ga) with distinctive magmatism of the Maddhapara basement rocks have agreeable relationship with the CITZ, India. The consistent magmatism is also common in the Transamazonian of South America, Trans-Hudson orogeny in North America, Bohemian Massif and the Svecofennian, Poland, have identified the sequential growth of the continent through the amalgamation of juvenile terrains, succeeded by a major collisional orogeny. Such Paleoproterozoic subduction-related orogens in Australia have similar counterparts in Antarctica and other part of the world. These types of Paleoproterozoic magmatism dominantly contributed

Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville B core, Chesapeake Bay impact structure, USA

Science.gov (United States)

Townsend, G.N.; Gibson, R.L.; Horton, J. Wright; Reimold, W.U.; Schmitt, R.T.; Bartosova, K.

2009-01-01

The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ?? fibrolite ?? garnet ?? tourmaline ?? pyrite ?? rutile ?? pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite- K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase- quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ?? biotite ?? garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ?? muscovite ?? pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ?? epidote ?? amphibole. The lower basement-derived section and both megablocks exhibit similar middleto upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafi c source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites. ?? 2009 The Geological Society of America.

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)

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

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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.

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)

The basement control on Xiazhuang uranium ore field in south sector of Wuyi tumescence and relevant geological problems

International Nuclear Information System (INIS)

Xu Dazhong; Xue Zhenhua

1994-01-01

Based on the two rift-trench tectonic framework in Wuyi as well as its adjacent areas proposed previously, this study takes Yingtan-Nancheng-Anyuan-Heyuan tenacity fracture belt as the geological boundary between two types of uranium deposits (granite and volcanic rock). It is noted that the distinct function of Caledonian movement in this area is the formation of the linear migmatization and granitization on the basis of rift and tumescence basement. Simultaneously, according to the new discovery of hypometamorphic rock and large scaled ductile mylonitized zone in Xiazhuang uranium ore field and its adjacent area, it is concluded that the Xiazhuang uranium ore field is the result of multiple tectonism and magmatic activations on the Caledonian hot dome on the basis of ancient basement. Because the uranium mineralization is present in two kinds of rocks (ductile and brittle), it is suggested that the types of mineralization in Xiazhuang can be considered in order to guide the further prospecting

Provenance of Austroalpine basement metasediments: tightening up Early Palaeozoic connections between peri-Gondwanan domains of central Europe and Northern Africa

Science.gov (United States)

Siegesmund, S.; Oriolo, S.; Heinrichs, T.; Basei, M. A. S.; Nolte, N.; Hüttenrauch, F.; Schulz, B.

2018-03-01

New U-Pb and Lu-Hf detrital zircon data together with whole-rock geochemical and Sm-Nd data were obtained for paragneisses of the Austroalpine basement south of the Tauern Window. Geochemically immature metasediments of the Northern-Defereggen-Petzeck (Ötztal-Bundschuh nappe system) and Defereggen (Drauzug-Gurktal nappe system) groups contain zircon age populations which indicate derivation mainly from Pan-African orogens. Younger, generally mature metasediments of the Gailtal Metamorphic Basement (Drauzug-Gurktal nappe system), Thurntaler Phyllite Group (Drauzug-Gurktal nappe system) and Val Visdende Formation (South Alpine Basement) were possibly derived from more distant sources. Their significantly larger abundances of pre-Pan-African zircons record a more advanced stage of downwearing of the Pan-African belts and erosion of older basement when the Austroalpine terrane was part of the Early Palaeozoic Northern Gondwana passive margin. Most zircon age spectra are dominated by Ediacaran sources, with lesser Cryogenian, Tonian and Stenian contributions and subordinate Paleoproterozoic and Neoarchean ages. These age patterns are similar to those recorded by Cambro-Ordovician sedimentary sequences in northeastern Africa between Libya and Jordan, and in some pre-Variscan basement inliers of Europe (e.g. Dinarides-Hellenides, Alboran microplate). Therefore, the most likely sources seem to be in the northeastern Saharan Metacraton and the Northern Arabian-Nubian Shield (Sinai), further supported by whole-rock Sm-Nd and zircon Lu-Hf data.

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)

Progress of the LASL dry hot rock geothermal energy project

Science.gov (United States)

Smith, M. C.

1974-01-01

The possibilities and problems of extracting energy from geothermal reservoirs which do not spontaneously yield useful amounts of steam or hot water are discussed. The system for accomplishing this which is being developed first is a pressurized-water circulation loop intended for use in relatively impermeable hot rock. It will consist of two holes connected through the hot rock by a very large hydraulic fracture and connected at the surface through the primary heat exchanger of an energy utilization system. Preliminary experiments in a hole 2576 ft (0.7852 km) deep, extending about 470 ft (143 m) into the Precambrian basement rock underlying the Jemez Plateau of north-central New Mexico, revealed no unexpected difficulties in drilling or hydraulically fracturing such rock at a temperature of approximately 100 C, and demonstrated a permeability low enough so that it appeared probable that pressurized water could be contained by the basement rock. Similar experiments are in progress in a second hole, now 6701 ft (2.043 km) deep, about 1.5 miles (2.4 km) south of the first one.

Fault-Slip Data Analysis and Cover Versus Basement Fracture Patterns - Implications for Subsurface Technical Processes in Thuringia, Germany

Science.gov (United States)

Kasch, N.; Kley, J.; Navabpour, P.; Siegburg, M.; Malz, A.

2014-12-01

Recent investigations in Thuringia, Central Germany, focus on the potential for carbon sequestration, groundwater supply and geothermal energy. We report on the results of an integrated fault-slip data analysis to characterize the geometries and kinematics of systematic fractures in contrasting basement and cover rock lithologies. The lithostratigraphy of the area comprises locally exposed crystalline rocks and intermittently overlying Permian volcanic and clastic sedimentary rocks, together referred to as basement. A Late Permian sequence of evaporites, carbonates and shale constitutes the transition to the continuous sedimentary cover of Triassic age. Major NW-SE-striking fault zones and minor NNE-SSW-striking faults affect this stratigraphic succession. These characteristic narrow deforming areas ( 15 km) non-deforming areas suggesting localized zones of mechanical weakness, which can be confirmed by the frequent reactivation of single fault strands. Along the major fault zones, the basement and cover contain dominant inclined to sub-vertical NW-SE-striking fractures. These fractures indicate successive normal, dextral strike-slip and reverse senses of slip, evidencing events of NNE-SSW extension and contraction. Another system of mostly sub-vertical NNW-SSE- and NE-SW-striking conjugate strike-slip faults mainly developed within the cover implies NNE-SSW contraction and WNW-ESE extension. Earthquake focal mechanisms and in-situ stress measurements reveal a NW-SE trend for the modern SHmax. Nevertheless, fractures and fault-slip indicators are rare in the non-deforming areas, which characterizes Thuringia as a dual domain of (1) large unfractured areas and (2) narrow zones of high potential for technical applications. Our data therefore provide a basis for estimation of slip and dilation tendency of the contrasting fractures in the basement and cover under the present-day stress field, which must be taken into account for different subsurface technical

Effects of Water and Low-Medium Temperature on Limestone from Mt Etna basement

Science.gov (United States)

Castagna, Angela; Ougier-Simonin, Audrey; Benson, Philip; Browning, John; Fazio, Marco; Walker, Richard; Vinciguerra, Sergio

2017-04-01

Mount Etna volcano, Sicily, sits atop a structurally complex sedimentary basement continuously subjected to tectonic deformation. The flyschoid formations belonging to the Appenninic-Maghrebian Chain (AMC) and making up the accretionary wedge of a regional fold-and-thrust belt lie above carbonate Hyblean Plateau (HP) sequences, belonging to the African plate. Carbonate rocks represent a major component of the sedimentary basement: they are spread throughout the AMC as continuous strata and discontinuous lenses, and are the main constituent (e.g., Comiso Limestone) of the HP foreland. Etna is an active volcanic environment, characterized by complex stress field distributions, magmatic and non-magmatic fluid circulation, and elevated temperature gradients; the edifice has been constructed at various rates and with variable distribution of effusive products. These intrinsic and extrinsic parameters are known to impact the rheological behaviour of rocks. Previous triaxial deformation studies on carbonates (Tavel Limestone, Solnhofen Limestone and Comiso Limestone) have shown the importance of temperature, and the presence of water as pore fluid, on the mechanical strength and failure mode of the rocks. However, to our knowledge, no previous studies have considered the distal heating effect of intrusions on the carbonate mechanical strength from the basement. Here we investigate the behaviour under varying P-T conditions at constant strain rate (10-5 s-1) on both dry and water saturated samples of Comiso Limestone, a low-porosity (10.2% average) carbonate rock belonging to the HP. We ran separate conventional triaxial experiments at various confining effective pressure from 0 up to 50 MPa at room temperature (20°C), in both dry and drained water-saturated conditions, using natural samples, and thermally-treated samples (150°C, 300°C, and 450°C). Acoustic Emissions and P-wave velocities were recorded during the experiments. Sample failure covers the brittle and

U-Pb zircon geochronology of intrusive and basement rocks in the Jacurici Valley region, Sao Francisco Craton, BA, Brazil

International Nuclear Information System (INIS)

Silveira, Carlos Jose Sobrinho da; Frantz, Jose Carlos; Marques, Juliana Charao; Roos, Siegbert; Peixoto, Vinicius Medina

2015-01-01

The Jacurici Complex, located in the NE of the Sao Francisco Craton, is constituted by several Cr-mineralized mafic-ultramafic N-S bodies, possible fragments of a single sill disrupted during deformation. Some works suggest it is intruded on the Serrinha Block while others consider it in the Salvador-Curaca Belt. The basement on this region is informally divided into paragneisses and orthogneisses; the latter is supposed to be younger considering it is less deformed. Petrography revealed that some of the paragneisses are alkali-feldspar granite strongly milonitized. The orthogneisses occur at the north and consist, at least in part, of monzogranites with heterogeneous deformation, locally of low temperature. U-Pb zircon dating were performed for five representative samples. Just three provided good concordia ages. A mafic rock produced a 2102 ± 5 Ma age and it is petrographically similar to the metanorites described in the Jacurici Complex, being interpreted as the record of the first pulses of the mafic magmatism. A monzogranite yielded a 2995 ± 15 Ma age, older than expected, related to the Serrinha Block. The alkali-feldspar granite yielded a 2081 ± 3 Ma age. The Itiuba Syenite and the pegmatites that crosscut the Jacurici Complex have similar ages. Considering the lack of information about the supracrustal sequence that hosts the intrusive alkaline and mafic-ultramafic rocks at the Ipueira and the Medrado areas, it is possible that part of the terrain belongs to the Salvador-Curaca Belt. We suggest that the Jacurici Complex could be intruded after the tectonic amalgamation between the Serrinha Block and the older part of the Salvador-Curaca Belt and, therefore, could be hosted by both terrains. (author)

The Dalradian rocks of Scotland: an introduction

OpenAIRE

Stephenson, David; Mendum, John R.; Fettes, Douglas J.; Leslie, A. Graham

2013-01-01

The Dalradian Supergroup and its basement rocks, together with younger plutons, underpin most of the Grampian Highlands and the islands of the Inner Hebrides between the Highland Boundary and Great Glen faults. The Dalradian is a mid-Neoproterozoic to early-Ordovician sequence of largely clastic metasedimentary rocks, with some volcanic units, which were deformed and metamorphosed to varying degrees during the Early Palaeozoic Caledonian Orogeny. Sedimentation of the lower parts of the Da...

Numerical analysis of temperature distribution due to basement radiogenic heat production, St. Lawrence Lowlands, eastern Canada

Science.gov (United States)

Liu, Hejuan; Giroux, Bernard; Harris, Lyal B.; Mansour, John

2017-04-01

Although eastern Canada is considered as having a low potential for high-temperature geothermal resources, the possibility for additional localized radioactive heat sources in Mesoproterozoic Grenvillian basement to parts of the Palaeozoic St. Lawrence Lowlands in Quebec, Canada, suggests that this potential should be reassessed. However, such a task remains hard to achieve due to scarcity of heat flow data and ambiguity about the nature of the basement. To get an appraisal, the impact of radiogenic heat production for different Grenville Province crystalline basement units on temperature distribution at depth was simulated using the Underworld Geothermal numerical modelling code. The region south of Trois-Rivières was selected as representative for the St. Lawrence Lowlands. An existing 3D geological model based on well log data, seismic profiles and surface geology was used to build a catalogue of plausible thermal models. Statistical analyses of radiogenic element (U, Th, K) concentrations from neighbouring outcropping Grenville domains indicate that the radiogenic heat production of rocks in the modelled region is in the range of 0.34-3.24 μW/m3, with variations in the range of 0.94-5.83 μW/m3 for the Portneuf-Mauricie (PM) Domain, 0.02-4.13 μW/m3 for the Shawinigan Domain (Morin Terrane), and 0.34-1.96 μW/m3 for the Parc des Laurentides (PDL) Domain. Various scenarios considering basement characteristics similar to the PM domain, Morin Terrane and PDL Domain were modelled. The results show that the temperature difference between the scenarios can be as much as 12 °C at a depth of 5 km. The results also show that the temperature distribution is strongly affected by both the concentration of radiogenic elements and the thermal conductivity of the basement rocks. The thermal conductivity in the basement affects the trend of temperature change between two different geological units, and the spatial extent of thermal anomalies. The validity of the results was

U-Pb detrital zircon geochronology from the basement of the Central Qilian Terrane: implications for tectonic evolution of northeastern Tibetan Plateau

Science.gov (United States)

Liu, Changfeng; Wu, Chen; Zhou, Zhiguang; Yan, Zhu; Jiang, Tian; Song, Zhijie; Liu, Wencan; Yang, Xin; Zhang, Hongyuan

2018-03-01

The Tuolai Group dominates the Central Qilian Terrane, and there are different opinions on the age and tectonic attribute of the Tuolai Group. Based on large-scale geologic mapping and zircon dating, the Tuolai Group is divided into four parts: metamorphic supracrustal rocks, Neoproterozoic acid intrusive rocks, early-middle Ordovician acid intrusive rocks and middle Ordovician basic intrusive rocks. The metamorphic supracrustal rocks are the redefined Tuolai complex-group and include gneiss and schist assemblage by faulting contact. Zircon U-Pb LA-MC-ICP-MS dating was conducted on these samples of gneiss and migmatite from the gneiss assemblage, quartzite, two-mica schist and slate from the schist assemblage. The five detrital samples possess similar age spectra; have detrital zircon U-Pb main peak ages of 1.7 Ga with youngest U-Pb ages of 1150 Ma. They are intruded by Neoproterozoic acid intrusive rocks. Therefore, the Tuolai Group belonging to late Mesoproterozoic and early Neoproterozoic. With this caveat in mind, we believe that U-Pb detrital zircon dating, together with the geologic constraints obtained from this study and early work in the neighboring regions. We suggest that the formation age of the entire crystalline basement rocks of metasedimentary sequence from the Central Qilian Terrane should be constrained between the Late Mesoproterozoic and the Late Neoproterozoic, but not the previous Paleoproterozoic. The basement of the Central Qilian Terrane contains the typical Grenville ages, which indicates the Centre Qilian Terrane have been experienced the Grenville orogeny event.

Heterogeneity of groundwater storage properties in the critical zone of Irish metamorphic basement from geophysical surveys and petrographic analyses

Science.gov (United States)

Comte, Jean-Christophe; Cassidy, Rachel; Caulfield, John; Nitsche, Janka; Ofterdinger, Ulrich; Wilson, Christopher

2016-04-01

Weathered/fractured bedrock aquifers contain groundwater resources that are crucial in hard rock basement regions for rural water supply and maintaining river flow and ecosystem resilience. Groundwater storage in metamorphic rocks is subject to high spatial variations due to the large degree of heterogeneity in fracture occurrence and weathering patterns. Point measurements such as borehole testing are, in most cases, insufficient to characterise and quantify those storage variations because borehole sampling density is usually much lower than the scale of heterogeneities. A suite of geophysical and petrographic investigations was implemented in the weathered/fractured micaschist basement of Donegal, NW Ireland. Electrical Resistivity Tomography provided a high resolution 2D distribution of subsurface resistivities. Resistivity variations were transferred into storage properties (i.e. porosities) in the saturated critical zone of the aquifer through application of a petrophysical model derived from Archie's Law. The petrophysical model was calibrated using complementary borehole gamma logging and clay petrographic analysis at multi-depth well clusters distributed along a hillslope transect at the site. The resulting distribution of porosities shows large spatial variations along the studied transect. With depth, porosities rapidly decrease from about a few % in the uppermost, highly weathered basement to less than 0.5% in the deep unweathered basement, which is encountered at depths of between 10 and 50m below the ground surface. Along the hillslope, porosities decrease with distance from the river in the valley floor, ranging between 5% at the river to less than 1% at the top of the hill. Local traces of regional fault zones that intersect the transect are responsible for local increases in porosity in relation to deeper fracturing and weathering. Such degrees of spatial variation in porosity are expected to have a major impact on the modality of the response of

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).…

A low-δ18O intrusive breccia from Koegel Fontein, South Africa: Remobilisation of basement that was hydrothermally altered during global glaciation?

Science.gov (United States)

Olianti, Camille A. E.; Harris, Chris

2018-02-01

The Cretaceous Koegel Fontein igneous complex is situated on the west coast of South Africa, and has a high proportion of rocks with abnormally low δ18O values. The rocks with the lowest δ18O values (- 5.2‰) belong to intrusive matrix-supported breccia pipes and dykes, containing a variety of clast types. The breccia rocks range in SiO2 from 44 to 68 wt% and their whole-rock δ18O values vary between - 5.2‰ and + 1.8‰. The major and trace element composition of the breccia rocks is consistent with them containing variable proportions of clasts of Cretaceous intrusive rocks and basement gneiss and the matrix being fluidized material derived from the same source as the clasts. Based on the nature of the clasts contained in the breccia, it was emplaced just prior to intrusion of the main Rietpoort Granite at 134 Ma. All components of the breccia have low δ18O value and, at least in the case of the gneiss clasts, this predates incorporation in the fluidized material. Although the early Cretaceous appears to have been a period of cold climate, it is unlikely that the δ18O values of ambient precipitation ( - 10‰) would have been low enough to have generated the required 18O-depletion. The basement gneiss was probably 2-3 km below the Cretaceous surface, minimizing the possibility of interaction with isotopically unmodified meteoric water, and there is no evidence for foundered blocks of cover rocks in the breccia. There is, therefore, no evidence for downwards movement of material. We favour a model where basement gneiss interacted with extremely 18O-depleted fluid during crustal reworking at 547 Ma, a time of global glaciation. Low-δ18O metamorphic fluids produced by dehydration melting of 18O-depleted gneiss became trapped and, as the fluid pressure increased, failure of the seal resulted in explosive upwards movement of fluidized breccia. Migration was along pre-existing dykes, incorporating fragments of these dykes, as well as the country rock gneiss.

Impact of climate changes during the last 5 million years on groundwater in basement aquifers.

Science.gov (United States)

Aquilina, Luc; Vergnaud-Ayraud, Virginie; Les Landes, Antoine Armandine; Pauwels, Hélène; Davy, Philippe; Pételet-Giraud, Emmanuelle; Labasque, Thierry; Roques, Clément; Chatton, Eliot; Bour, Olivier; Ben Maamar, Sarah; Dufresne, Alexis; Khaska, Mahmoud; Le Gal La Salle, Corinne; Barbecot, Florent

2015-09-22

Climate change is thought to have major effects on groundwater resources. There is however a limited knowledge of the impacts of past climate changes such as warm or glacial periods on groundwater although marine or glacial fluids may have circulated in basements during these periods. Geochemical investigations of groundwater at shallow depth (80-400 m) in the Armorican basement (western France) revealed three major phases of evolution: (1) Mio-Pliocene transgressions led to marine water introduction in the whole rock porosity through density and then diffusion processes, (2) intensive and rapid recharge after the glacial maximum down to several hundred meters depths, (3) a present-day regime of groundwater circulation limited to shallow depth. This work identifies important constraints regarding the mechanisms responsible for both marine and glacial fluid migrations and their preservation within a basement. It defines the first clear time scales of these processes and thus provides a unique case for understanding the effects of climate changes on hydrogeology in basements. It reveals that glacial water is supplied in significant amounts to deep aquifers even in permafrosted zones. It also emphasizes the vulnerability of modern groundwater hydrosystems to climate change as groundwater active aquifers is restricted to shallow depths.

Reactivated basement structures in the central Savannah River area and their relationship to coastal plain deformation

International Nuclear Information System (INIS)

Cumbest, R.J.; Price, V.; Temples, T.J.; Fallaw, W.C.; Snipes, D.S.

1993-01-01

Structural surface mapping and geophysical studies have identified several faults in the crystalline basement and overlying Coastal Plain sedimentary sequences in the central Savannah River area. Major subsurface basement shear zones occur parallel to and near Upper Three Runs Creek and Tinker Creek and are associated with linear aeromagnetic anomalies. Reflection seismic imaging of the basement shows a band of southeast dipping events parallel to Upper Three Runs Creek. Drill core from basement contain phyllonites, mylonites, fault breccia and pseudotachylite. The magnetic anomalies also mark the boundary separating greenschist facies metavolcanic rocks from amphibolite facies felsic gneiss, schist, and amphibolite. These features are similar to those that characterize other Paleozoic faults of the Eastern Piedmont Fault system. Reflection seismic imaging shows the sub-Cretaceous unconformity as well defined and easily identified event as well as easily traced laterally extensive events in Coastal Plain sequences. The unconformity and sedimentary sequences are faulted or deformed in several locations which also coincide with changes in dip of the unconformity. In the vicinity of Upper Three Runs Creek the unconformity shows a broad warping across which the elevation drops to the southeast and sedimentary sequences show a marked rate of thickening southeast. This indicates deformation of the basement exerted a control on deposition of the Coastal Plain sediments with down to the southeast movement. The basement shear zones are closely associated with the Dunbarton basin and are probable reactivated Paleozoic structures associated with extensional basin development as commonly seen associated with extensional basins on the east coast of North America

The discovery of hornblende-garnet-zoisite hornfels in the metamorphic basement of Xiangshan uranium ore field

International Nuclear Information System (INIS)

Jiang Zhenpin; Dong Yongjie; Yu Jianfa; Hu Rongquan; Wu Shuilin

2007-01-01

Some vein rocks are found among mica schist in the metamorphic rock area of the Xiangshan uranium ore field. They are petrologically denominated as hornblende-garnet-zoisite hornfels. The primitive rocks are basic vein rocks. The hornfels are formed under thermal metamorphism with the temperature about 640 degree C and belong to low-pressure faces. This is closed to the form condition of EarlyMiddle Proterozoic metamorphic rocks in the area. The metamorphism forming the hornfels means that the Early-Middle Proterozoic metamorphic rocks was superimposed to another thermal metamorphism and produced the second phase metamorphic minerals such as staurolite, almandine and biotite. The lattice of the second phase metamorphic mineral developed continuously with the first phase minerals. The overlapping metamorphism made the first phase metamorphic mineral suffer recrystallization, auto purification and idiomorphism. The discovery of hornfelsed basic rock veins discloses that strong geologic process with the activity of fault, magma and metamorphism were still taken placed in Paleozoic era within the metamorphic basement of the Xiangshan uranium ore field. (authors)

Nature of the Yucatan Block Basement as Derived From Study of Granitic Clasts in the Impact Breccias of Chicxulub Crater

Science.gov (United States)

Vera-Sanchez, P.; Rebolledo-Vieyra, M.; Perez-Cruz, L.; Urrutia-Fucugauchi, J.

2008-05-01

The tectonic and petrologic nature of the basement of the Yucatan Block is studied from analyses of basement clasts present in the impact suevitic breccias of Chicxulub crater. The impact breccias have been sampled as part of the drilling projects conducted in the Yucatan peninsula by Petroleos Mexicanos, the National University of Mexico and the Chicxulub Scientific Drilling Project. Samples analyzed come mainly from the Yaxcopoil-1, Tekax, and Santa Elena boreholes, and partly from Pemex boreholes. In this study we concentrate on clasts of the granites, granodiorites and quartzmonzonites in the impact breccias. We report major and trace element geochemical and petrological data, which are compared with data from the granitic and volcanic rocks from the Maya Mountains in Belize and from the Swannee terrane in Florida. Basement granitic clasts analyzed present intermediate to acidic sub-alkaline compositions. Plots of major oxides (e.g., Al2O3, Fe2O3, TiO2 and CaO) and trace elements (e.g., Th, Y, Hf, Nb and Zr) versus silica allow separation of samples into two major groups, which can be compared to units in the Maya Mountains and in Florida basement. The impact suevitic breccia samples have been affected by alteration likely related to the hydrothermal processes associated with the crater melt sheet. Cloritization, seritization and fenitization alterations are recognized, due to the long term hydrothermalism. Krogh et al. (1993) reported U-Pb dates on zircons from the suevitic breccias, which gave dates of 545 +/- 5 Ma and 418 +/- 6 Ma, which were interpreted in terms of the deep granitic metamorphic Yucatan basement. The younger date correlates with the age for the Osceola Granite and the St. Lucie metamorphic complex of the Swannee terrane in the Florida peninsula. The intrusive rocks in the Yucatan basement may be related to approx. 418 Ma ago collisional event in the Late Silurian.

Petrophysics Features of the Hydrocarbon Reservoirs in the Precambrian Crystalline Basement

Science.gov (United States)

Plotnikova, Irina

2014-05-01

A prerequisite for determining the distribution patterns of reservoir zones on the section of crystalline basement (CB) is the solution of a number of problems connected with the study of the nature and structure of empty spaces of reservoirs with crystalline basement (CB) and the impact of petrological, and tectonic factors and the intensity of the secondary transformation of rocks. We decided to choose the Novoelhovskaya well # 20009 as an object of our research because of the following factors. Firstly, the depth of the drilling of the Precambrian crystalline rocks was 4077 m ( advance heading - 5881 m) and it is a maximum for the Volga-Urals region. Secondly, petrographic cut of the well is made on core and waste water, and the latter was sampled regularly and studied macroscopically. Thirdly, a wide range of geophysical studies were performed for this well, which allowed to identify promising areas of collector with high probability. Fourth, along with geological and technical studies that were carried out continuously (including washing and bore hole redressing periods), the studies of the gaseous component of deep samples of clay wash were also carried out, which indirectly helped us estimate reservoir properties and fluid saturation permeable zones. As a result of comprehensive analysis of the stone material and the results of the geophysical studies we could confidently distinguish 5 with strata different composition and structure in the cut of the well. The dominating role in each of them is performed by rocks belonging to one of the structural-material complexes of Archean, and local variations in composition and properties are caused by later processes of granitization on different stages and high temperature diaphthoresis imposed on them. Total capacity of reservoir zones identified according to geophysical studies reached 1034.2 m, which corresponds to 25.8% of the total capacity of 5 rock masses. However, the distribution of reservoirs within the cut

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

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...

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

Punta del este terrane: meso proterozoic basement and neo proterozoic cover

International Nuclear Information System (INIS)

Preciozzi, F.; Sanchez Bettucci, L.; Basei, M.; Peel, E.; Oyhantcabal, P.; Cordani, U.

2003-01-01

Full text: Eastern basement of Uruguay consists of Meso and Neoproterozoic rocks. Mesoproterozoic basement had been deformed by pre-Brasiliano and Brasiliano events. Regional variations in this basement and in the Neoproterozoic cover show equivalent deformation styles and intensities. Models proposed for tectonic evolution have been scarce and confusing. Specially, the ones that concern the moment of collision and/or juxtaposition of blocks. The Punta del Este Terrane (PET) is composed of gneisses and migmatites formed between 1000 Ma to 900 Ma (Preciozzi et al., 2001). These rocks had been strongly reworked during Brasiliano and Rio Doce orogenesis (ca. 900-500 Ma). This crustal segment represents a high grade metamorphic terrane, which is correlated to some gneissic complexes southwest of Africa. Particularly, it is correlated to Kibaran-Namaqua Belt in Namibia. U-Pb ages between 1000 Ma and 900 Ma, obtained in zircons from tonalitic granitoids, are interpreted as indicative of their crystallization (Fig. 1). Besides, anatectic fluids related to migmatites leucosomes yielded ages of ca. 520 to 540 Ma. This denotes that superimposed metamorphic conditions during Brasiliano orogenesis reached, at least, lower amphibolite facies. PET basement gneisses present Sm-Nd model ages (TDM) between 2.4 to 1.8 Ga, showing long crustal residence, corroborated by the very negative εNd values of –1.3 and –14.3. During Brazilian orogenesy they were affected by deformation processes and anatexis. Metasedimentary PET cover occurs near La Paloma and Rocha towns. It is represented by a siliciclastic metasedimentary succession corresponding to the Rocha formation. In La Pedrera town recognized three sedimentary facies were (1-3): (1) sandstones and pelites; (2) green pelites; and (3) rhytmites. The transition from facies (1) to facies (3) shows the passage from fluvial environment with tidal influence to tidal flat with predominance of sub tidal deposits (Pazos and S�

Burial history, thermal history and hydrocarbon generation modelling of the Jurassic source rocks in the basement of the Polish Carpathian Foredeep and Outer Carpathians (SE Poland)

Science.gov (United States)

Kosakowski, Paweł; Wróbel, Magdalena

2012-08-01

Burial history, thermal maturity, and timing of hydrocarbon generation were modelled for the Jurassic source rocks in the basement of the Carpathian Foredeep and marginal part of the Outer Carpathians. The area of investigation was bounded to the west by Kraków, to the east by Rzeszów. The modelling was carried out in profiles of wells: Będzienica 2, Dębica 10K, Góra Ropczycka 1K, Goleszów 5, Nawsie 1, Pławowice E1 and Pilzno 40. The organic matter, containing gas-prone Type III kerogen with an admixture of Type II kerogen, is immature or at most, early mature to 0.7 % in the vitrinite reflectance scale. The highest thermal maturity is recorded in the south-eastern part of the study area, where the Jurassic strata are buried deeper. The thermal modelling showed that the obtained organic matter maturity in the initial phase of the "oil window" is connected with the stage of the Carpathian overthrusting. The numerical modelling indicated that the onset of hydrocarbon generation from the Middle Jurassic source rocks was also connected with the Carpathian thrust belt. The peak of hydrocarbon generation took place in the orogenic stage of the overthrusting. The amount of generated hydrocarbons is generally small, which is a consequence of the low maturity and low transformation degree of kerogen. The generated hydrocarbons were not expelled from their source rock. An analysis of maturity distribution and transformation degree of the Jurassic organic matter shows that the best conditions for hydrocarbon generation occurred most probably in areas deeply buried under the Outer Carpathians. It is most probable that the "generation kitchen" should be searched for there.

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.

The role of basement inheritance faults in the recent fracture system of the inner shelf around Alboran Island, Western Mediterranean

Science.gov (United States)

Maestro-González, A.; Bárcenas, P.; Vázquez, J. T.; Díaz-Del-Río, V.

2008-02-01

Fractures associated with volcanic rock outcrops on the inner shelf of Alboran Island, Western Mediterranean, were mapped on the basis of a side-scan sonar mosaic. Absolute maximum fracture orientation frequency is NW SE to NNW SSE, with several sub-maxima oriented NNE SSW, NE SW and ENE WSW. The origin of the main fracture systems in Neogene and Quaternary rocks of the Alboran Basin (south Spain) appears to be controlled by older structures, namely NE SW and WNW ESE to NW SE faults which cross-cut the basement. These faults, pre-Tortonian in origin, have been reactivated since the early Neogene in the form of strike-slip and extensional movements linked to the recent stress field in this area. Fracture analysis of volcanic outcrops on the inner continental shelf of Alboran Island suggests that the shelf has been deformed into a narrow shear zone limited by two NE SW-trending, sub-parallel high-angle faults, the main orientation and density of which have been influenced by previous WNW ESE to NW SE basement fractures.

Characteristics and genesis of porphyroclastic lava rock in Xiangshan

International Nuclear Information System (INIS)

Zhou Xiaohua; Wang Zhuning

2012-01-01

Due to the transitional characteristics of porphyroclastic lava rock in Xiangshan of Jiangxi province, there are a variety of views on its genesis, petrographic attribution. This is because the marginal facies of the porphyroclastic lava is with ignimbrite and tuff characteristics, its transition phase has the characteristics of lava, and its intermediate phase has the feature of sub-volcanic rocks, further more, different texture of the rocks bears transition relationship. By the study of mineral composition, REE pattern, trace elements, isotopes, we put forward that the porphyroclastic lava is formed by the remelting of basement metamorphic rocks. The rocks was believed to be formed in the environment similar to volcanics and subvolcanics, and quite different to plutonic rocks due to the features of low-structure of potassium feldspar phenocrysts and solution mechanism, because the porphyroclastic lava phenocrysts occurs as fragments and maybe related to cryptoexplosion. Therefore the rocks was believed to belong to the volcano extrusive facies. (authors)

Testing the Mojave-Sonora megashear hypothesis: Evidence from Paleoproterozoic igneous rocks and deformed Mesozoic strata in Sonora, Mexico

Science.gov (United States)

Amato, J.M.; Lawton, T.F.; Mauel, D.J.; Leggett, W.J.; Gonzalez-Leon, C. M.; Farmer, G.L.; Wooden, J.L.

2009-01-01

U-Pb ages and Nd isotope values of Proterozoic rocks in Sonora, Mexico, indicate the presence of Caborca-type basement, predicted to lie only south of the Mojave-Sonora mega-shear, 40 km north of the postulated megashear. Granitoids have U-Pb zircon ages of 1763-1737 Ma and 1076 Ma, with ??Nd(t) values from +1.4 to -4.3, typical of the Caborca block. Lower Jurassic strata near the Proterozoic rocks contain large granitic clasts with U-Pb ages and ??Nd(t) values indistinguishable from those of Caborcan basement. Caborca-type basement was thus present at this location north of the megashear by 190 Ma, the depositional age of the Jurassic strata. The Proterozoic rocks are interpreted as parautochthonous, exhumed and juxtaposed against the Mesozoic section by a reverse fault that formed a footwall shortcut across a Jurassic normal fault. Geochronology, isotope geochemistry, and structural geology are therefore inconsistent with Late Jurassic megashear displacement and require either that no major transcurrent structure is present in Sonora or that strike-slip displacement occurred prior to Early Jurassic time. ?? 2009 The Geological Society of America.

Preliminary isotopic data from some amphibolites of the metamorphic basement of the Colombian Central Cordillera

International Nuclear Information System (INIS)

Correa M, Ana Maria; Martens K, Uwe; Ordonez C, Oswaldo; Pimentel, Marcio M; Restrepo A, Jorge Julian

2001-01-01

Various amphibolite bodies are exposed in the Antioquia Department, Colombia, mainly around the cities of Medellin and El Retiro. Two types of amphibolites occur in the study area; the first one is considered as part of an ophiolite complex and the second one correspond to amphibolites associated to metasediments from the basement of the Colombian Central Cordillera. The present work refers to these last ones. The relationships between amphibolite bodies and other lythological units are the following ones: Intercalation of amphibolites layers with metasediments in the unit migmatites and granulites of El Retiro. The Medellin amphibolites are conformably overlaid by the paragneisses of Las Penas. The granodiorite body represented by the Antioquian Batolith is intrusive in the metamorphic rocks and the Medellin Dunites unit is in thrust fault contact with Medellin amphibolites. These amphibolites have been studied by Botero (1963), Gonzalez (1976 and 1980), Restrepo and Toussaint (1984), Ardila (1986), Restrepo (1986), Rendon (1999) and, Correa and Martens (2000). Available radiometric ages on the amphibolites come from former works by Restrepo y Toussaint (1978), Restrepo et al. (1991) that presented K-Ar ages in amphiboles and a Rb-Sr isochron which yielded a Cretaceous age that they interpreted as a metamorphic age. This work presents new evidences, obtained from field work, petrography, rock geochemistry and specially the first isotopic data on these amphibolites from the Central Cordillera Metamorphic Basement (au)

Basic rocks in Finland

International Nuclear Information System (INIS)

Piirainen, T.; Gehoer, S.; Iljina, M.; Kaerki, A.; Paakkola, J.; Vuollo, J.

1992-10-01

Basic igneous rocks, containing less than 52% SiO 2 , constitute an important part of the Finnish Archaean and Proterozoic crust. In the Archaean crust exist two units which contain the majority of the basic rocks. The Arcaean basic rocks are metavolcanics and situated in the Greenstone Belts of Eastern Finland. They are divided into two units. The greenstones of the lower one are tholeiites, komatiites and basaltic komatiites. The upper consists of bimodal series of volcanics and the basic rocks of which are Fe-tholeiites, basaltic komatiites and komatiites. Proterozoic basic rocks are divided into seven groups according to their ages. The Proterozoic igneous activity started by the volominous basic magmatism 2.44 Ga ago. During this stage formed the layered intrusions and related dykes in the Northern Finland. 2.2 Ga old basic rocks are situated at the margins of Karelian formations. 2.1 Ga aged Fe-tholeiitic magmatic activity is widespread in Eastern and Northern Finland. The basic rocks of 1.97 Ga age group are met within the Karelian Schist Belts as obducted ophiolite complexes but they occur also as tholeiitic diabase dykes cutting the Karelian schists and Archean basement. The intrusions and the volcanics of the 1.9 Ga old basic igneous activity are mostly encountered around the Granitoid Complex of Central Finland. Subjotnian, 1.6 Ga aged tholeiitic diabases are situated around the Rapakivi massifs of Southern Finland, and postjotnian, 1.2 Ga diabases in Western Finland where they form dykes cutting Svecofennian rocks

Permeability in fractured rocks from deep geothermal boreholes in the Upper Rhine Graben

Science.gov (United States)

Vidal, Jeanne; Whitechurch, Hubert; Genter, Albert; Schmittbuhl, Jean; Baujard, Clément

2015-04-01

Permeability in fractured rocks from deep geothermal boreholes in the Upper Rhine Graben Vidal J.1, Whitechurch H.1, Genter A.2, Schmittbuhl J.1, Baujard C.2 1 EOST, Université de Strasbourg 2 ES-Géothermie, Strasbourg The thermal regime of the Upper Rhine Graben (URG) is characterized by a series of geothermal anomalies on its French part near Soultz-sous-Forêts, Rittershoffen and in the surrounding area of Strasbourg. Sedimentary formations of these areas host oil field widely exploited in the past which exhibit exceptionally high temperature gradients. Thus, geothermal anomalies are superimposed to the oil fields which are interpreted as natural brine advection occurring inside a nearly vertical multi-scale fracture system cross-cutting both deep-seated Triassic sediments and Paleozoic crystalline basement. The sediments-basement interface is therefore very challenging for geothermal industry because most of the geothermal resource is trapped there within natural fractures. Several deep geothermal projects exploit local geothermal energy to use the heat or produce electricity and thus target permeable fractured rocks at this interface. In 1980, a geothermal exploration well was drilled close to Strasbourg down to the Permian sediments at 3220 m depth. Bottom hole temperature was estimated to 148°C but the natural flow rate was too low for an economic profitability (geothermal site by drilling five boreholes, three of which extend to 5 km depth. They identified a temperature of 200° C at 5 km depth in the granitic basement but with a variable flow rate. Hydraulic and chemical stimulation operations were applied in order to increase the initial low permeability by reactivating and dissolving sealed fractures in basement. The productivity was considerably improved and allows geothermal exploitation at 165° C and 20 L/s. Recent studies revealed the occurrences of permeable fractures in the limestones of Muschelkalk and the sandstones of Buntsandstein also. For

Geochemical, microtextural and petrological studies of the Samba prospect in the Zambian Copperbelt basement: a metamorphosed Palaeoproterozoic porphyry Cu deposit.

Science.gov (United States)

Master, Sharad; Mirrander Ndhlovu, N.

2015-04-01

Ever since Wakefield (1978, IMM Trans., B87, 43-52) described a porphyry-type meta-morphosed Cu prospect, the ca 50 Mt, 0.5% Cu Samba deposit (12.717°S, 27.833°E), hosted by porphyry-associated quartz-sericite-biotite schists in northern Zambia, there has been controversy about its origin and significance. This is because it is situated in the basement to the world's largest stratabound sediment-hosted copper province, the Central African Copperbelt, which is hosted by rocks of the Neoproterozoic Katanga Supergroup. Mineralization in the pre-Katangan basement has long played a prominent role in ore genetic models, with some authors suggesting that basement Cu mineralization may have been recycled into the Katangan basin through erosion and redeposition, while others have suggested that the circulation of fluids through Cu-rich basement may have leached out the metals which are found concentrated in the Katangan orebodies. On the basis of ca 490-460 Ma Ar-Ar ages, Hitzman et al. (2012, Sillitoe Vol., SEG Spec. Publ., 16, 487-514) suggested that Samba represents late-stage impregnation of copper mineralization into the basement, and that it was one of the youngest copper deposits known in the Central African Copperbelt. If the Samba deposit really is that young, then it would have post-dated regional deformation and metamorphism (560-510 Ma), and it ought to be undeformed and unmetamorphosed. The Samba mineralization consists of chalcopyrite and bornite, occurring as disseminations, stringers and veinlets, found in a zone >1 km along strike, in steeply-dipping lenses up to 10m thick and >150m deep. Our new major and trace element XRF geochemical data (14 samples) show that the host rocks are mainly calc-alkaline metadacites. Cu is correlated with Ag (Cu/Ag ~10,000:1) with no Au or Mo. Our study focused on the microtextures and petrology of the Samba ores. We confirm that there is alteration of similar style to that accompanying classical porphyry Cu mineralization

NEW DATA ON AGE AND NATURE OF CARBONIZATION WITHIN SOUTHERN FLANK OF THE BAIKAL LEDGE OF THE SIBERIAN CRATON BASEMENT

Directory of Open Access Journals (Sweden)

Yu. V. Danilova

2017-01-01

Full Text Available The Baikal ledge rock formations in the Siberian craton structure are included in the Akitkan mobile belt which is considered as the Late Paleoproterozoic independent island arc system moved up to the ancient basement during the terrains amalgamation 1.91–2.00 Ga ago (Fig. 1 [Rosen, 2003; Gladkochub et al., 2009; Didenko et al., 2013].

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)

Isotopic data bearing on the origin of Mesozoic and Tertiary granitic rocks in the western United States

International Nuclear Information System (INIS)

DePaolo, D.J.; Farmer, G.L.

1984-01-01

A regional survey of initial Nd and Sr isotopic compositions has been done on Mesozoic and Tertiary granitic rocks from a 500 000 km 2 area in California, Nevada, Utah, Arizona, and Colorado. The plutons, which range in composition from quartz diorite to monzogranite, are intruded into accreted oceanic geosynclinal terrains in the west and north and into Precambrian basement in the east. Broad geographic coverage allows the data to be interpreted in the context of the regional pre-Mesozoic crustal structure. Initial Nd isotopic compositions exhibit a huge range, encompassing values typical of oceanic magmatic arcs and Archean basement. The sources of the magmas can be inferred from the systematic geographic variability of Nd isotopic compositions. The plutons in the accreted terrains represent mantle-derived magma that assimilated crust while differentiating at deep levels. Those emplaced into Precambrian basement are mainly derived from the crust. The regional patterns can be understood in terms of: (1) the flux of mantle magma entering the crust; (2) crustal thickness; and (3) crustal age. The mantle magma flux apparently decreased inland; in the main batholith belts purely crustal granitic rocks are not observed because the flux was too large. Inland, crustal granite is common because mantle magma was scarce and the crust was thick, and hot enough to melt. The epsilonsub(Nd) values of peraluminous granite formed by melting of the Precambrian basement depend on the age of the local basement source. (author)

Percolation of diagenetic fluids in the Archaean basement of the Franceville basin

Science.gov (United States)

Mouélé, Idalina Moubiya; Dudoignon, Patrick; Albani, Abderrazak El; Cuney, Michel; Boiron, Marie-Christine; Gauthier-Lafaye, François

2014-01-01

The Palaeoproterozoic Franceville basin, Gabon, is mainly known for its high-grade uranium deposits, which are the only ones known to act as natural nuclear fission reactors. Previous work in the Kiéné region investigated the nature of the fluids responsible for these natural nuclear reactors. The present work focuses on the top of the Archaean granitic basement, specifically, to identify and date the successive alteration events that affected this basement just below the unconformity separating it from the Palaeoproterozoic basin. Core from four drill holes crosscutting the basin-basement unconformity have been studied. Dating is based on U-Pb isotopic analyses performed on monazite. The origin of fluids is discussed from the study of fluid inclusion planes (FIP) in quartz from basement granitoids. From the deepest part of the drill holes to the unconformable boundary with the basin, propylitic alteration assemblages are progressively replaced by illite and locally by a phengite + Fe chlorite ± Fe oxide assemblage. Illitic alteration is particularly strong along the sediment-granitoid contact and is associated with quartz dissolution. It was followed by calcite and anhydrite precipitation as fracture fillings. U-Pb isotopic dating outlines three successive events: a 3.0-2.9-Ga primary magmatic event, a 2.6-Ga propylitic alteration and a late 1.9-Ga diagenetic event. Fluid inclusion microthermometry suggests the circulation of three types of fluids: (1) a Na-Ca-rich diagenetic brine, (2) a moderately saline (diagenetic + meteoric) fluid, and (3) a low-salinity fluid of probable meteoric origin. These fluids are similar to those previously identified within the overlying sedimentary rocks of the Franceville basin. Overall, the data collected in this study show that the Proterozoic-Archaean unconformity has operated as a major flow corridor for fluids circulation, around 1.9 Ga. highly saline diagenetic brines; hydrocarbon-rich fluids derived from organic matter

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...... chondrocytes express these four cardinal components of basement membranes and demonstrated by immunohistochemistry that the proteins are present in bovine and mouse cartilage tissues and are deposited in a thin pericellular structure. Immunoelectron microscopy confirmed high laminin concentration...... becomes less distinct, especially in areas of obvious mechanical attrition. Interestingly, individual laminin subunits were located in different zones of the cartilage, with laminin alpha1 showing preferential localization around a select population of superficial layer chondrocytes. We propose...

High-quality heat flow determination from the crystalline basement of the south-east margin of North China Craton

Science.gov (United States)

Jiang, Guangzheng; Tang, Xiaoyin; Rao, Song; Gao, Peng; Zhang, Linyou; Zhao, Ping; Hu, Shengbiao

2016-03-01

Very few of heat flow data have come from the crystalline basement in the North China Craton but rather from boreholes in the sedimentary cover of oil-gas basins. Explorations for hot dry rock (HDR) geothermal resources and porphyry gold deposits in eastern China offer now valuable opportunities to study the terrestrial heat flow in the crystalline basement. In this study, we obtained continuous temperature logs from two boreholes (the LZ borehole with a depth of 3471 m and the DR borehole with a depth of 2179 m) located in the south-east margin of the North China Craton. The boreholes have experienced long shut-in times (442 days and 261 days for the LZ borehole and DR borehole, respectively); thus, it can be expected that the temperature conditions have re-equilibrated after drilling and drill-mud circulation. Rock thermal conductivity and radiogenic heat production were measured for 68 crystalline rock samples from these two boreholes. The measured heat-flow density was determined to be 71.8 ± 2.3 mW m-2 (for the LZ borehole) and 91.5 ± 1.2 mW m-2 (for the DR borehole). The heat flow for the LZ borehole is close to the value of 75 mW m-2 determined in the Chinese Continental Scientific Drilling main hole (CCSD MH), both being in the Sulu-Dabie orogenic belt and thus able to verify each other. The value for the DR borehole is higher than the above two values, which supports former high heat-flow values determined in the Bohai Bay Basin.

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada

Science.gov (United States)

du Bray, Edward A.; John, David A.; Box, Stephen E.; Vikre, Peter G.; Fleck, Robert J.; Cousens, Brian L.

2013-04-23

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada // // This report presents petrographic and geochemical data for samples collected during investigations of Tertiary volcanism in the Bodie Hills of California and Nevada. Igneous rocks in the area are principally 15–6 Ma subduction-related volcanic rocks of the Bodie Hills volcanic field but also include 3.9–0.1 Ma rocks of the bimodal, post-subduction Aurora volcanic field. Limited petrographic results for local basement rocks, including Mesozoic granitoid rocks and their metamorphic host rocks, are also included in the compilation. The petrographic data include visual estimates of phenocryst abundances as well as other diagnostic petrographic criteria. The geochemical data include whole-rock major oxide and trace element data, as well as limited whole-rock isotopic data.

Combined stable isotope trajectories for water-rock interaction

International Nuclear Information System (INIS)

Blattner, P.; Department of Scientific and Industrial Research, Lower Hutt

1981-01-01

The 'mixed' model of water-rock interaction (1980 Workshop) is explained in detail. Based on the magnitude of the oxygen isotope shifts of their recharge water, different geothermal systems can be placed in an evolutionary series, from incipient (large shift of water) to mature (small shift of water). Isotopes of different chemical elements may be combined, to yield a stringent test of whether or not a given change in rock composition may be ascribed to interaction with water (L-shaped trajectories). For the acidic eruptives of the Taupo Volcanic Zone, available strontium and oxygen isotope data practically rule out an origin by partial melting of greywacke basement

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.

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.

New Sm/Nd and U/Pb geochronological constraints of the Archean to neoproterozoic evolution of the Amparo basement complex of the Central Ribeira Belt, Southeastern Brazil

International Nuclear Information System (INIS)

Fetter, A.H.; Hackspacher, P.C.; Ebbert, H.D; Dantas, E.L; Costa, A.C.D. da

2001-01-01

The Amparo Basement Complex is a distinctive collage of migmatitic tronjhemitetonalite- granodiorite (TTG) orthogneisses that represents the older basement exposures within the Central Ribeira Belt, a Late Neoproterozoic (ca. 600 Ma) collisional belt in southeastern Brazil. These basement gneisses are overlain by Mesoproterozoic to Neoproterozoic supracrustal sequences, and intruded by Neoproterozoic collisional granitoids. Pioneering Rb/Sr, Pb/Pb and K/Ar geochronological studies of the Amparo Complex, e.g. (Wernick et al., 1981; Wernick and Oliveira, 1986; Arthur, 1988; Tassinari, 1988; Campos Neto, 1991) provided some initial insights into the antiquity and geologic evolution of the complex, but little about the crustal evolution of the constituent gneisses. Furthermore, the susceptibility of these systems to partial isotopic resetting, left some doubt about the timing and true number of geologic events recorded by these polydeformed rocks. Recent Sm/Nd whole rock (Dantas et al., 2000) and new U/Pb single crystal zircon and monazite data obtained from the Amparo Complex, however, now furnish information on the crustal growth history of the basement and provide precise age constraints on the timing of events related to the geologic evolution of the complex. Based on these new data, it appears that the oldest rocks within the complex are polymigmatized tronjhemitic gneisses located near the town of Amparo. The oldest phase of this migmatite yields a U/Pb zircon age of 3,024 +/- 9 Ma. Sm/Nd data from this locale yields a Nd T(DM) model age of 3.28 Ga suggesting that the genesis of this crustal unit involved some input from yet older crust. Data from banded tonalitic gneisses collected ca. 50 km south of Amparo indicate that subsequent Archean crustal growth around the older core occurred around 2.77 Ga (U/Pb zircon age of 2,772 +/- 26 Ma. A Nd T(DM) model age of 3.02 Ga obtained from these tonalites also indicate enrichment from older crustal sources during their

The vascular basement membrane in the healthy and pathological brain.

Science.gov (United States)

Thomsen, Maj S; Routhe, Lisa J; Moos, Torben

2017-10-01

The vascular basement membrane contributes to the integrity of the blood-brain barrier (BBB), which is formed by brain capillary endothelial cells (BCECs). The BCECs receive support from pericytes embedded in the vascular basement membrane and from astrocyte endfeet. The vascular basement membrane forms a three-dimensional protein network predominantly composed of laminin, collagen IV, nidogen, and heparan sulfate proteoglycans that mutually support interactions between BCECs, pericytes, and astrocytes. Major changes in the molecular composition of the vascular basement membrane are observed in acute and chronic neuropathological settings. In the present review, we cover the significance of the vascular basement membrane in the healthy and pathological brain. In stroke, loss of BBB integrity is accompanied by upregulation of proteolytic enzymes and degradation of vascular basement membrane proteins. There is yet no causal relationship between expression or activity of matrix proteases and the degradation of vascular matrix proteins in vivo. In Alzheimer's disease, changes in the vascular basement membrane include accumulation of Aβ, composite changes, and thickening. The physical properties of the vascular basement membrane carry the potential of obstructing drug delivery to the brain, e.g. thickening of the basement membrane can affect drug delivery to the brain, especially the delivery of nanoparticles.

Litho stratigraphy of precambrian rocks in middle Xingu river basin -Altamira, Para state, Brazil

International Nuclear Information System (INIS)

Santos, M.V. dos; Sousa Filho, E.E. dos; Tassinari, C.C.G.

1988-01-01

The basement rocks from the Xingu river is divided into five litho stratigraphic units. They are broadly characterized by domains of ortho and para gneisses, volcano-sedimentary sequences, migmatites and by syntectonic and latetectonic granitoids. In addition acid to intermediate volcanics (Iriri formation) and several sub-volcanic granitic plutons (Maloquinha suite) also occur within the investigated area, as well as basic intrusions and minor arenous sediments covers, slightly metamorphosed. Geochronological studies carried out on the basement rocks and on the volcanics demonstrates an geologic evolution restricted to the trans Amazonian cycle (2.1 - 1.9 Ga). Sr isotopic evolution (high initial 87 Sr/ 86 Sr ratios) suggest that strong reworking of crustal material occurred at this time, in association with the tectonic evolution of the Maroni-Itacaiunas mobile belt related to the lower proterozoic, which borders the northern and northerneast part of the Archean central Amazonian province. (author)

Compilation of new and previously published geochemical and modal data for Mesoproterozoic igneous rocks of the St. Francois Mountains, southeast Missouri

Science.gov (United States)

du Bray, Edward A.; Day, Warren C.; Meighan, Corey J.

2018-04-16

The purpose of this report is to present recently acquired as well as previously published geochemical and modal petrographic data for igneous rocks in the St. Francois Mountains, southeast Missouri, as part of an ongoing effort to understand the regional geology and ore deposits of the Mesoproterozoic basement rocks of southeast Missouri, USA. The report includes geochemical data that is (1) newly acquired by the U.S. Geological Survey and (2) compiled from numerous sources published during the last fifty-five years. These data are required for ongoing petrogenetic investigations of these rocks. Voluminous Mesoproterozoic igneous rocks in the St. Francois Mountains of southeast Missouri constitute the basement buried beneath Paleozoic sedimentary rock that is over 600 meters thick in places. The Mesoproterozoic rocks of southeast Missouri represent a significant component of approximately 1.4 billion-year-old (Ga) igneous rocks that crop out extensively in North America along the southeast margin of Laurentia and subsequent researchers suggested that iron oxide-copper deposits in the St. Francois Mountains are genetically associated with ca. 1.4 Ga magmatism in this region. The geochemical and modal data sets described herein were compiled to support investigations concerning the tectonic setting and petrologic processes responsible for the associated magmatism.

Air exchange rates and migration of VOCs in basements and residences.

Science.gov (United States)

Du, L; Batterman, S; Godwin, C; Rowe, Z; Chin, J-Y

2015-12-01

Basements can influence indoor air quality by affecting air exchange rates (AERs) and by the presence of emission sources of volatile organic compounds (VOCs) and other pollutants. We characterized VOC levels, AERs, and interzonal flows between basements and occupied spaces in 74 residences in Detroit, Michigan. Flows were measured using a steady-state multitracer system, and 7-day VOC measurements were collected using passive samplers in both living areas and basements. A walk-through survey/inspection was conducted in each residence. AERs in residences and basements averaged 0.51 and 1.52/h, respectively, and had strong and opposite seasonal trends, for example, AERs were highest in residences during the summer, and highest in basements during the winter. Airflows from basements to occupied spaces also varied seasonally. VOC concentration distributions were right-skewed, for example, 90th percentile benzene, toluene, naphthalene, and limonene concentrations were 4.0, 19.1, 20.3, and 51.0 μg/m(3), respectively; maximum concentrations were 54, 888, 1117, and 134 μg/m(3). Identified VOC sources in basements included solvents, household cleaners, air fresheners, smoking, and gasoline-powered equipment. The number and type of potential VOC sources found in basements are significant and problematic, and may warrant advisories regarding the storage and use of potentially strong VOCs sources in basements. Few IAQ studies have examined basements. A sizable volume of air can flow between the basement and living area, and AERs in these two zones can differ considerably. In many residences, the basement contains significant emission sources and contributes a large fraction of VOC concentrations found in the living area. Exposures can be lowered by removing VOC sources from the basement; other exposure management options, such as local ventilation or isolation, are unlikely to be practical. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Inheritance, Variscan tectonometamorphic evolution and Permian to Mesozoic rejuvenations in the metamorphic basement complexes of the Romanian Carpathians revealed by monazite microprobe geochronology

Science.gov (United States)

Săbău, Gavril; Negulescu, Elena

2014-05-01

South Carpathians contain lower Paleozoic or older units intruded by Ordovician granitoids, imbricated with juvenile Variscan slivers, the structural sequence differing in individual basement complexes. So, in the Leaota Massif the lowermost term of the sequence is prograde Variscan, tectonically overlain by reworked lower Paleozoic gneisses, supporting thrust sheets with very low- to low-grade Variscan schists. In the Făgăraş Massif a lower Paleozoic (Cumpăna) complex bearing a strong Variscan overprint, straddles Variscan juvenile rocks, and the lowermost visible structural level is assumed by upper Carboniferous to Permian juvenile medium-grade metamorphic schists. In the Lotru Metamorphic Suite of the Alpine Getic Nappe, the Variscan stacking is overprinted by post-orogenic differential uplift, documented by the correlation among younging ages, structural and metamorphic low-pressure overprints, recording often higher metamorphic temperatures. The most spectacular structure is Upper Jurassic in age, contains high-grade metamorphic rocks and peraluminous anatectic granitoids, is outlined by a deformed boundary evolving from ductile to brittle regime during cooling, and induces a thermal overprint in the neighbouring rocks. In the basement units thrust over the Getic Nappe, the Sibişel unit yielded Permian prograde peak metamorphic ages and Triassic post-peak overprints, while an adjacent gneissic unit (Laz) delivered an exclusively Cretaceous age pattern. Unexpectedly young metamorphic ages resulted also for the East Carpathians and the Apuseni Mountains. While most of the ages obtained so far correspond to Variscan retrogression of older basement units, the lowermost structural unit of the infra-Bucovinian nappe system in the East Carpathians yielded Upper Cretaceous metamorphic ages in apparently monometamorphic medium-grade schists. In the Apuseni Mountains, schists of the Baia de Arieş Unit display an Upper Jurassic age spectrum, corresponding to a clearly

Perlecan and basement membrane-chondroitin sulfate proteoglycan (bamacan) are two basement membrane chondroitin/dermatan sulfate proteoglycans in the Engelbreth-Holm-Swarm tumor matrix

DEFF Research Database (Denmark)

Couchman, J R; Kapoor, R; Sthanam, M

1996-01-01

heparan sulfate proteoglycan, widespread in many basement membranes and connective tissues. We now identify two distinct proteoglycan species from this tumor source, which are substituted with galactosaminoglycans and which show basement membrane localization by immunohistochemistry. One species......The presence of proteoglycans bearing galactosaminoglycan chains has been reported, but none has been identified previously in the matrix of the Engelbreth-Holm-Swarm tumor, which is a source of several basement membrane components. This tumor matrix contains perlecan, a large, low buoyant density......-CSPG are distinct in core protein structure. Both are, however, basement membrane components, although there are tissue-specific differences in their distribution....

Late Mesoproterozoic to Early Paleozoic history of metamorphic basement from the southeastern Chiapas Massif Complex, Mexico, and implications for the evolution of NW Gondwana

Science.gov (United States)

Weber, Bodo; González-Guzmán, Reneé; Manjarrez-Juárez, Román; Cisneros de León, Alejandro; Martens, Uwe; Solari, Luigi; Hecht, Lutz; Valencia, Victor

2018-02-01

In this paper, U-Pb zircon geochronology, Lu-Hf and Sm-Nd isotope systematics, geochemistry and geothermobarometry of metaigneous basement rocks exposed in the southeastern Chiapas Massif Complex are presented. Geologic mapping of the newly defined "El Triunfo Complex" located at the southeastern edge of the Chiapas Massif reveals (1) partial melting of a metamorphic basement mainly constituted by mafic metaigneous rocks (Candelaria unit), (2) an Ediacaran metasedimentary sequence (Jocote unit), and (3) occurrence of massif-type anorthosite. All these units are intruded by undeformed Ordovician plutonic rocks of the Motozintla suite. Pressure and temperature estimates using Ca-amphiboles, plagioclase and phengite revealed prograde metamorphism that reached peak conditions at 650 °C and 6 kbar, sufficient for partial melting under water saturated conditions. Relict rutile in titanite and clinopyroxene in amphibolite further indicate a previous metamorphic event at higher P-T conditions. U-Pb zircon ages from felsic orthogneiss boudins hosted in deformed amphibolite and migmatite yield crystallization ages of 1.0 Ga, indicating that dry granitic protoliths represent remnants of Rodinia-type basement. Additionally, a mid-Tonian ( 920 Ma) metamorphic overprint is suggested by recrystallized zircon from a banded gneiss. Zircon from folded amphibolite samples yield mainly Ordovician ages ranging from 457 to 444 Ma that are indistinguishable from the age of the undeformed Motozintla plutonic suite. Similar ages between igneous- and metamorphic- zircon suggest a coeval formation during a high-grade metamorphic event, in which textural discrepancies are explained in terms of differing zircon formation mechanisms such as sub-solidus recrystallization and precipitation from anatectic melts. In addition, some amphibolite samples contain inherited zircon yielding Stenian-Tonian ages around 1.0 Ga. Lu-Hf and Sm-Nd isotopes and geochemical data indicate that the protoliths of

U-Pb SHRIMP and Sm-Nd geochronology of the Silvania Volcanics and Jurubatuba Granite: juvenile paleoproterozoic crust in the basement of the Neo proterozoic Brasilia Belt, Goias, central Brazil

International Nuclear Information System (INIS)

Fischel, Danielle P.; Pimentel, Marcio M.; Fuck, Reinhardt A.; Armstrong, Richard

2001-01-01

U-Pb SHRIMP and Sm-Nd isotopic ages were determined for felsic meta volcanic rocks from the Silvania Sequence and Jurubatuba Granite in the central part of the Brasilia Belt. Zircon grains from a meta volcanic sample yielded 2115 ± 23 Ma and from the granite yielded 2089 ±14 Ma, interpreted as crystallization ages of these rocks. Six meta volcanic samples of the Silvania Sequence yielded a six-point whole-rock Sm-Nd isochron indicating a crystallization age of 2262 ±110 Ma and positive ε Nd (T) = +3.0 interpreted as a juvenile magmatic event. Nd isotopic analyses on samples from the Jurubatuba Granite have Paleoproterozoic T DM model ages between 2.30 and 2.42 Ga and ε Nd (T) values vary between -0.22 and -0.58. The oldest T DM value refers to a sedimentary xenolith in the granite. These results suggest crystallization ages of Silvania volcanics and Jurubatuba Granite are the first evidence of a ca. 2.14-2.08 juvenile magmatic event in the basement of the central part of the Brasilia Belt that implies the presence of arc/suture hidden in reworked basement of the Brasilia Belt. (author)

U-Pb SHRIMP and Sm-Nd geochronology of the Silvania Volcanics and Jurubatuba Granite: juvenile paleoproterozoic crust in the basement of the Neo proterozoic Brasilia Belt, Goias, central Brazil

Energy Technology Data Exchange (ETDEWEB)

Fischel, Danielle P.; Pimentel, Marcio M.; Fuck, Reinhardt A. [Brasilia Univ., DF (Brazil). Inst. de Geociencias; Armstrong, Richard [Australian National Univ., Canberra (Australia). Research School of Earth Sciences

2001-09-15

U-Pb SHRIMP and Sm-Nd isotopic ages were determined for felsic meta volcanic rocks from the Silvania Sequence and Jurubatuba Granite in the central part of the Brasilia Belt. Zircon grains from a meta volcanic sample yielded 2115 {+-} 23 Ma and from the granite yielded 2089 {+-}14 Ma, interpreted as crystallization ages of these rocks. Six meta volcanic samples of the Silvania Sequence yielded a six-point whole-rock Sm-Nd isochron indicating a crystallization age of 2262 {+-}110 Ma and positive {epsilon}{sub Nd} (T) = +3.0 interpreted as a juvenile magmatic event. Nd isotopic analyses on samples from the Jurubatuba Granite have Paleoproterozoic T{sub DM} model ages between 2.30 and 2.42 Ga and {epsilon}{sub Nd} (T) values vary between -0.22 and -0.58. The oldest T{sub DM} value refers to a sedimentary xenolith in the granite. These results suggest crystallization ages of Silvania volcanics and Jurubatuba Granite are the first evidence of a ca. 2.14-2.08 juvenile magmatic event in the basement of the central part of the Brasilia Belt that implies the presence of arc/suture hidden in reworked basement of the Brasilia Belt. (author)

Rock Rb-Sr ages from Bananal region - Sao Paulo State, Brazil

International Nuclear Information System (INIS)

Dias Neto, C.M.; Tassinari, C.G.C.; Silva, M.E.

1996-01-01

New Rb-Sr whole rock isochron ages have been determined for the main lithological units that occur in Sao Paulo and Rio de Janeiro States. These rocks belong to Serra do Mar domain. The purpose of this work is to characterize the sequence of the geological events as well as the possible relationship between the different rocks. The geochronological data suggest that the paragneisses and the basement rocks, represented by ortho gneisses nuclei, were generated under amphibolite conditions around 700 Ma. At the same time the leucogranites were generated by partial melting processes and injected into both gneiss types. Tarditectonic granitic magmatic activities took place within ductile shear zones. One of the granites, the Getulandia granite, yielded an age of 514 Ma, falling in the range of the late Brasiliano Cycle which extended into the Middle Cambrian. (author). 9 figs., 1 tab

Magnetic Basement Depth Inversion in the Space Domain

Science.gov (United States)

Nunes, Tiago Mane; Barbosa, Valéria Cristina F.; Silva, João Batista C.

2008-10-01

We present a total-field anomaly inversion method to determine both the basement relief and the magnetization direction (inclination and declination) of a 2D sedimentary basin presuming negligible sediment magnetization. Our method assumes that the magnetic intensity contrast is constant and known. We use a nonspectral approach based on approximating the vertical cross section of the sedimentary basin by a polygon, whose uppermost vertices are forced to coincide with the basin outcrop, which are presumably known. For fixed values of the x coordinates our method estimates the z coordinates of the unknown polygon vertices. To obtain the magnetization direction we assume that besides the total-field anomaly, information about the basement’s outcrops at the basin borders and the basement depths at a few points is available. To obtain stable depth-to-basement estimates we impose overall smoothness and positivity constraints on the parameter estimates. Tests on synthetic data showed that the simultaneous estimation of the irregular basement relief and the magnetization direction yields good estimates for the relief despite the mild instability in the magnetization direction. The inversion of aeromagnetic data from the onshore Almada Basin, Brazil, revealed a shallow, eastward-dipping basement basin.

Gondwanan/peri-Gondwanan origin for the Uchee terrane, Alabama and georgia: Carolina zone or Suwannee terrane(?) and its suture with Grenvillian basement of the Pine Mountain window

Science.gov (United States)

Steltenpohl, M.G.; Mueller, P.M.; Heatherington, A.L.; Hanley, T.B.; Wooden, J.L.

2008-01-01

The poorly known, suspect, Uchee terrane occupies a critical tectonic position with regard to how and when peri-Gondwanan (Carolina) and Gondwanan (Suwannee) terranes were sutured to Laurentia. It lies sandwiched between Laurentian(?) continental basement exposed in the Pine Mountain window and adjacent buried Gondwanan crust of the Suwannee terrane. The Uchee terrane has been proposed as both a septum of Piedmont rocks that once was continuous across the erosionally breached Pine Mountain window or part of the Carolina zone. To help resolve this issue, we conducted U-Pb (SHRIMP-RG) (sensitive high-resolution ion microprobe-reverse geometry) zircon studies and whole-rock isotopic analyses of principal metasedimentary and metaplutonic units. U-Pb ages for zircons from the Phenix City Gneiss suggest igneous crystallization at ca. 620 Ma, inheritance ca. 1000 to ca. 1700 Ma, and a ca. 300 Ma (Alleghanian) overprint recorded by zircon rims. Zircons from the metasedimentary/metavolcaniclastic Moffits Mill Schist yield bimodal dates at ca. 620 and 640 Ma. The 620 to 640 Ma dates make these rocks age-equivalent to the oldest parts of the Carolina slate belt (Virgilina and Savannah River) and strongly suggest a Gondwanan (Pan-African and/or Trans-Brasiliano) origin for the Uchee terrane. Alternatively, the Uchee terrane may be correlative with metamorphic basement of the Suwannee terrane. The ca. 300 Ma overgrowths on zircons are compatible with previously reported 295 to 288 Ma 40Ar/39Ar hornblende dates on Uchee terrane rocks, which were interpreted to indicate deep tectonic burial of the Uchee terrane contemporaneous with the Alleghanian orogeny recorded in the foreland. Temperature-time paths for the Uchee terrane are similar to that of the Pine Mountain terrane, indicating a minimum age of ca. 295 Ma for docking. In terms of tectono-metamorphic history of the Uchee terrane, it is important to note that no evidence for intermediate "Appalachian" dates (e.g, Acadian or

Exhumation of Basement-cored Uplifts: Example of the Kyrgyz Range Quantified with Apatite Fission-track Thermochronology

Science.gov (United States)

Sobel, Edward R.; Oskin, Michael; Burbank, Douglas; Mikolaichuk, Alexander

2005-01-01

The Kyrgyz Range, the northernmost portion of the Kyrgyzstan Tien Shan, displays topographic evidence for lateral propagation of surface uplift and exhumation. The highest and most deeply dissected segment lies in the center of the range. To the east, topography and relief decrease, and preserved remnants of a Cretaceous regional erosion surface imply minimal amounts of bedrock exhumation. The timing of exhumation of range segments defines the lateral propagation rate of the range-bounding reverse fault and quantifies the time and erosion depth needed to transform a mountain range from a juvenile to a mature morphology. New apatite fission-track (AFT) data from three transects from the eastern Kyrgyz Range, combined with published AFT data, demonstrate that the range has propagated over 110 km eastwards over the last 7-11 Myr. Based on the thermal and topographic evolutionary history, we present a model for a time-varying exhumation rate driven by rock uplift and changes in erodability and the time scale of geomorphic adjustment to surface uplift. Easily eroded, Cenozoic sedimentary rocks overlying resistant basement control early, rapid exhumation and slow surface upliftrates. As increasing amounts of resistant basement are exposed, exhumation rates decrease while surface uplift rates are sustained or increase, thereby growing topography. As the range becomes high enough to cause ice accumulation and develop steep river valleys, fluvial and glacial erosion become more powerful and exhumation rates once again increase. Independently determined range-noma1 shortening rates have also varied over time, suggesting a feedback between erosional efficiency and shortening rate.

ESR dating of fault rocks

International Nuclear Information System (INIS)

Lee, Hee Kwon

2003-02-01

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene

ESR dating of fault rocks

Energy Technology Data Exchange (ETDEWEB)

Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

2003-02-15

Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene.

NATURAL BASEMENT VENTILATION AS A RADON MITIGATION TECHNIQUE

Science.gov (United States)

The report documents a study of natural basement ventilation in two research houses during both the summer cooling season and the winter heating season. NOTE: Natural basement ventilation has always been recommended as a way to reduce radon levels in houses. However, its efficacy...

Basement domain map of the conterminous United States and Alaska

Science.gov (United States)

Lund, Karen; Box, Stephen E.; Holm-Denoma, Christopher S.; San Juan, Carma A.; Blakely, Richard J.; Saltus, Richard W.; Anderson, Eric D.; DeWitt, Ed

2015-01-01

The basement-domain map is a compilation of basement domains in the conterminous United States and Alaska designed to be used at 1:5,000,000-scale, particularly as a base layer for national-scale mineral resource assessments. Seventy-seven basement domains are represented as eighty-three polygons on the map. The domains are based on interpretations of basement composition, origin, and architecture and developed from a variety of sources. Analysis of previously published basement, lithotectonic, and terrane maps as well as models of planetary development were used to formulate the concept of basement and the methodology of defining domains that spanned the ages of Archean to present but formed through different processes. The preliminary compilations for the study areas utilized these maps, national-scale gravity and aeromagnetic data, published and limited new age and isotopic data, limited new field investigations, and conventional geologic maps. Citation of the relevant source data for compilations and the source and types of original interpretation, as derived from different types of data, are provided in supporting descriptive text and tables.

Radon mitigation experience in houses with basements and adjoining crawl spaces

International Nuclear Information System (INIS)

Messing, M.; Henschel, D.B.

1990-01-01

Active soil depressurization systems were installed in four basement houses with adjoining crawl spaces in Maryland. In addition, existing soil depressurization systems were modified in two additional basement-plus-crawl-space houses. These six houses were selected to include both good and poor communication beneath the basement slab, and different degrees of importance of the crawl space as a source of the indoor radon. The radon reduction effectiveness was compared for: depressurization only under the basement slab; depressurization only under a polyethylene liner over the unpaved crawl-space floor; and simultaneous depressurization under both the basement slab and the crawl-space liner. The objective of this paper is to identify under what conditions treatment of the basement alone might provide sufficient radon reductions in houses of this substructure, and what incremental benefits might be achieved by also treating the crawl space

Basement Basalts from IODP Site 1438, Amami-Sankaku Basin: Implications for Sources and Melting Processes during Subduction Initiation in the Izu-Bonin-Mariana System

Science.gov (United States)

McCarthy, A. J.; Hickey-Vargas, R.; Yogodzinski, G. M.; Ishizuka, O.; Hocking, B.; Bizimis, M.; Savov, I. P.; Kusano, Y.; Arculus, R. J.

2016-12-01

IODP Expedition 351 Site 1438 is located in the Amami-Sankaku basin, just west of the Kyushu-Palau Ridge (KPR), a remnant of the early Izu-Bonin-Mariana (IBM) volcanic arc. 150 meters of basement basalt were drilled beneath 1460 m of volcaniclastic sediments and sedimentary rock. The age range inferred for these basalts is 51-52 Ma, close to the 48-52 Ma age of basalts associated with subduction initiation in the IBM forearc (forearc basalts or FABs). Site 1438 basement basalts form several distinct subunits, all relatively mafic (MgO = 6-14 %; Mg# = 51-83). Non-fluid-mobile incompatible trace element patterns are profoundly depleted. Sm/Nd (0.34-0.43) and Lu/Hf (0.18-0.37) reach values higher than most normal MORBs while La/Yb (0.31-0.98) and Ti/V (15.8-27.0) are lower. These features are shared with basalts drilled just west of the KPR at ODP Site 1201 and DSDP Site 447, and many FABs. Abundances of fluid-mobile incompatible elements vary together and are correlated with subunits defined by flow margins and rock physical properties, suggesting control by post-eruptive seawater alteration rather than varying inputs of subduction fluids. Hf-Nd isotopes for Site 1438 basement basalts range from (present-day) ɛNd of 7.0 to 9.5 and ɛHf of 14.5 to 19.8 in a well-correlated array. Their more radiogenic Hf-isotope character could indicate an Indian-type MORB source, however, basalts with ɛHf >16.5, are more radiogenic than many Indian MORB. Pb isotope data will help distinguish differing mantle source domains and origins for fluid-mobile elements. Overall, the combined geochemical data indicate that the mantle source of basement basalts in drill sites west of the KPR (1438, 1201, 447) are closely similar to those for FAB, and that as a group, these rocks are more depleted than more than 90% of global MORB. Our interpretation is that both IBM forearc basalts and basalts from drill sites immediately west of the KPR formed by melting of the same uniquely depleted mantle

Petrology of blueschist facies metamorphic rocks of the Meliata Unit

Directory of Open Access Journals (Sweden)

Faryad Shah Wali

1997-06-01

Full Text Available Meliata blueschists originated from basalts, limestones, pelites, psammitic and amphibolite facies basement rocks. Compositionally, the metabasalts have a geochemical signature mostly indicative of a transitional arc-MORB origin, but some mafic rocks having affinity with within plate basalts also present. The mafic blueschists consist of blue amphibole, epidote and albite, rarely also garnet, Na-pyroxene and chloritoid. Apart from phengite and quartz the metapelites and metapsammites contain one or more of the minerals: chloritoid, paragonite, glaucophane, albite, chlorite, occasionally also Na-pyroxene and garnet. Amphibolite facies rocks contain relic garnet, plagioclase and hornblende, the latter two replaced by albite and blue amphibole, respectively. The zoning patterns of blue amphibole, garnet and chloritoid suggest their formation during prograde stage of metamorphism. P-T conditions of meta-morphism are estimated to be about 350-460 oC and 10-12 kbar.

Calymmian magmatism in the basement of the Jauru Terrain (Rondonian - San Ignacio Province), Amazon Craton: U-Pb and Sm-Nd geochemistry and geochronology

Energy Technology Data Exchange (ETDEWEB)

Fachetti, Frankie James Serrano; Costa, Ana Claudia Dantas da; Silva, Carlos Humberto da, E-mail: frankiefachetti@hotmail.com, E-mail: acdcosta@ufmt.br, E-mail: chsilva@ufmt.br [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Instituto de Ciencias Exatas e da Terra

2016-11-01

The Taquarussu Orthogneiss and the Guadalupe Granodiorite, part of the Rondonian-San Ignacio Province basement, southwest of the Amazonian Craton, correspond to oriented bodies with a NW trend. The rocks show granodiorite composition with minor occurrences of coarse grained monzogranites consisting essentially of plagioclase, quartz, microcline, orthoclase and biotite. The accessory minerals are amphibole, titanite, garnet, apatite, epidote, zircon and opaque. The geochemical data indicate that the rocks are classified as granodiorites and monzogranites, with an intermediate to acid magmatism, sub-alkaline character, from the calc-alkaline to the high-K calc-alkaline series, with alumina ratios ranging from metaluminous to lightly peraluminous. The rocks were classified as generated in volcanic islands arc environment and the U-Pb data (SHRIMP zircon) show a concord age 1575 ± 6 Ma. The Sm-Nd model age (T{sub DM}) is 1.63 Ga with εNd (t = 1.57 Ga) ranging from -1.52 to +0.78. These data indicate that these rocks are probably a juvenile crust with a possible contamination of crustal rocks. (author)

U-Pb SHRIMP-RG zircon ages and Nd signature of lower Paleozoic rifting-related magmatism in the Variscan basement of the Eastern Pyrenees

Science.gov (United States)

Martinez, F.J.; Iriondo, A.; Dietsch, C.; Aleinikoff, J.N.; Peucat, J.J.; Cires, J.; Reche, J.; Capdevila, R.

2011-01-01

The ages of orthogneisses exposed in massifs of the Variscan chain can determine whether they are part of a pre-Neoproterozoic basement, a Neoproterozoic, Panafrican arc, or are, in fact, lower Paleozoic, and their isotopic compositions can be used to probe the nature of their source rocks, adding to the understanding of the types, distribution, and tectonic evolution of peri-Gondwanan crystalline basement. Using SHRIMP U-Pb zircon geochronology and Nd isotopic analysis, pre-Variscan metaigneous rocks from the N??ria massif in the Eastern Pyrenean axial zone and the Guilleries massif, 70km to the south, have been dated and their Nd signatures characterized. All dated orthogneisses from the N??ria massif have the same age within error, ~457Ma, including the Ribes granophyre, interpreted as a subvolcanic unit within Caradocian sediments contemporaneous with granitic magmas intruded into Cambro-Ordovician sediments at deeper levels. Orthogneisses in the Guilleries massif record essentially continuous magmatic activity during the Ordovician, beginning at the Cambro-Ordovician boundary (488??3Ma) and reaching a peak in the volume of magma in the early Late Ordovician (~460Ma). Metavolcanic rocks in the Guilleries massif were extruded at 452??4Ma and appear to have their intrusive equivalent in thin, deformed veins of granitic gneiss (451??7Ma) within metasedimentary rocks. In orthogneisses from both massifs, the cores of some zircons yield Neoproterozoic ages between ~520 and 900Ma. The age of deposition of a pre-Late Ordovician metapelite in the Guilleries massif is bracketed by the weighted average age of the youngest detrital zircon population, 582??11Ma, and the age of cross-cutting granitic veins, 451??7Ma. Older detrital zircons populations in this metapelite include Neoproterozoic (749-610Ma; n=10), Neo- to Mesoproterozoic (1.04-0.86Ga; n=7), Paleoproterozoic (2.02-1.59Ga; n=5), and Neoarchean (2.74-2.58Ga; n=3). Nd isotopic analyses of the N??ria and Guilleries

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)

Summary of northern Atlantic coastal plain hydrology and its relation to disposal of high-level radioactive waste in buried crystalline rock; a preliminary appraisal

Science.gov (United States)

Lloyd, O.B.; Larson, J.D.; Davis, R.W.

1985-01-01

Interpretation of available hydrologic data suggests that some areas beneath the Coastal Plain in the States of Delaware, Maryland, New Jersey, North Carolina, and Virginia might have some potential for the disposal of nuclear waste in crystalline rock that is buried beneath the Coastal Plain sediments. The areas of major interest occur where the top of the basement rock lies between 1,000 and 4,000 feet below sea level, the aquifer(s) immediately above the basement rock are saturated with saline water, confining material overlies the saline water bearing aquifer(s), and groundwater flow in the saline water aquifer(s) can be established. Preliminary data on (1) the distribution and thickness of the lowermost aquifers and confining beds, (2) the distribution of hydraulic conductivity in the lowermost aquifers, (3) estimated hydraulic heads and inferred direction of lateral groundwater flow for 1980, and (4) the distribution of saline water and brine, indicate eastern parts of the study area relatively best meet most of the criteria proposed for sediments that would overlie any potential buried crystalline-rock disposal site.

Radionuclide distribution in TMI-2 reactor building basement liquids and solids

International Nuclear Information System (INIS)

Horan, J.T.; McIsaac, C.V.; Keefer, D.G.

1984-01-01

As a result of the TMI-2 accident, approximately 2.46 x 10 6 L of contaminated water were released to the Reactor Building basement. The principal fission product release pathway from the damaged core was through the reactor coolant system (RCS) to the pressurizer, through the pressure-operated relief valve (PORV) on the pressurizer to the Reactor Coolant Drain Tank (RCDT), and then through the RCDT rupture disk to the Reactor Building basement. Since August 1979, a number of efforts have been made to determine the location, quantity, and composition of fission products released to the Reactor Building basement. These efforts have included sampling of the basement water and solids, the basement sump pump recirculation line, the RCDT, and visual surveys using a closed circuit television (CCTV) system. The analysis of basement samples has provided data on the physical and radioisotopic characteristics of the liquids and solids. This paper describes the sample collection techniques and discusses radiochemical analyses results

Deforming Etna's Basement: Implications for Edifice stability.

Science.gov (United States)

Bakker, Richard; Benson, Philip; Vinciguerra, Sergio

2013-04-01

At over 3 kilometers in height, Mt. Etna (Italy) is the largest volcano of continental Europe. The volcano formed on top of the alpine fold and thrust belt, with basaltic outflows lying unconformably on top of an alternation between sandstones, limestones and clays. Presently Etna's eastern flank is moving with speeds up to 2cm/yr to the east [Tibaldi and Groppelli, 2002]. It is the sequence of layers below the volcano that is thought to provide a complex, structurally controlled, mechanism to the volcano deformation as a whole. This is due to the interplay of gravitational forces, volcanic pressurization, and regional tectonics, which combine to play a complex role that remains poorly understood, especially when the physical and mechanical properties of the rocks are considered. In this study, we concentrate on the rock mechanical component, and in particular the formation known as Comiso Limestone. This limestone forms of one of the key lithologies of Etna's basement. The formation has been suggested to be affected by thermal weakening [Heap et al., 2013]. Previous work on Comiso Limestone suggests brittle behavior for the range of temperatures (up to 760 ˚C) and a significant reduction in strength with higher temperatures. [Mollo et al., 2011]. Chiodini et al [2011], speculate carbonate assimilation. This implies that the Carbondioxide created by decarbonatization, is able to escape. Using an internally heated "Paterson" type pressure vessel, we recreated conditions at 2-4 km depth (50-100 MPa) and using an anomalously high geotherm, as expected in volcanic settings (ranging from room to 600 ˚C). With the addition of confining pressure, we show a brittle to ductile transition occurs at a relatively low temperature of 300 ˚C. A significant decrease in strength occurs when the rock is exposed to temperatures exceeding 400 ˚C. In addition, we observe a significant difference in mechanical behavior between vented and unvented situations when decarbonatization is

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 ...

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.

Isotopic determinations of carbon and oxygen in the metasedimentary rocks of the Rio Pardo group-Bahia State, Brazil

International Nuclear Information System (INIS)

Costa Pinto, N.M.A.C.

1977-01-01

Determination of the carbon and oxygen isotopic compositions were made on approximately 100 samples of Late Precambrian metasedimentary rocks of the Rio Pardo Group from Southern Bahia. The results obtained show that carbon varies from δ 13 =C=5,73 per mille to δ 13 C=+9,00 per mille, and oxygen from δ 18 O=-1,87 per mille to δ 18 O=-19,67 per mille relative to PBD. The interpretations lead to some conclusions which confirm the validity the isotopic technique as auxiliary instrument in the study of geological problems. These include: 1) the evidence of a marine transgression during the Camaca sedimentation; 2) the probability that the dolomitic metalimestones of the Agua Preta formation belong to the Serra do Paraiso formation; 3) the assignment of the dolomitic metalismestones, which occur in Itiroro and which had been previously grouped with the crystalline basement rocks, to the Serra do Paraiso formation; 4) the removal of the marble from Serra do Paraiso formation and re-signment to the basement rocks, and finally; 5) the sedimentary evolution of the Rio Pardo Group from a typical fresh-water to a marine environment. (Author) [pt

Some results from the demonstration of indoor radon reduction measures in block basement houses

International Nuclear Information System (INIS)

Henschel, D.B.; Scott, A.G.

1989-01-01

Active soil ventilation techniques have been tested in 26 block-wall basement houses in eastern Pennsylvania with significantly elevated indoor radon concentrations, generally above 740 Bq/m 3 , and the results indicate that radon levels can be reduced substantially often below the U.S. Environmental Protection Agency (EPA) guideline of 148 Bq/m 3 , if effective suction can be drawn on the soil underneath the concrete slabs of these houses. Such effective suction appears achievable when either: (1) the house has a complete loop of drain tile around its footings for water drainage purposes, and suction is drawn on that loop; or (2) a sufficient number of suction pipes can be inserted at the proper locations into the crushed rock or the soil underneath the slab

Force-dependent breaching of the basement membrane.

Science.gov (United States)

Chang, Tammy T; Thakar, Dhruv; Weaver, Valerie M

2017-01-01

Clinically, non-invasive carcinomas are confined to the epithelial side of the basement membrane and are classified as benign, whereas invasive cancers invade through the basement membrane and thereby acquire the potential to metastasize. Recent findings suggest that, in addition to protease-mediated degradation and chemotaxis-stimulated migration, basement membrane invasion by malignant cells is significantly influenced by the stiffness of the associated interstitial extracellular matrix and the contractility of the tumor cells that is dictated in part by their oncogenic genotype. In this review, we highlight recent findings that illustrate unifying molecular mechanisms whereby these physical cues contribute to tissue fibrosis and malignancy in three epithelial organs: breast, pancreas, and liver. We also discuss the clinical implications of these findings and the biological properties and clinical challenges linked to the unique biology of each of these organs. Copyright © 2017 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

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

ventricular hypertrophy was maximal within 5 days. In immunohistochemical studies, fibronectin and laminin were increased and the basement membrane chondroitin sulfate proteoglycan decreased in both the subendothelial space and smooth muscle cell basement membranes of the aorta above the clip compared...... membrane components in the heart and vasculature peaked before maximal cardiac hypertrophy (5 days). These studies indicate that alterations in basement membrane component deposition in the hypertrophied vasculature occur at both transcriptional and translational levels and suggest that the cell attachment...

Argon and fission track dating of Alpine metamorphism and basement exhumation in the Sopron Mts. (Eastern Alps, Hungary): thermochronology or mineral growth?

International Nuclear Information System (INIS)

Balogh, K.; Dunkl, I.

2005-01-01

The crystalline basement rocks of the Sopron Mountains are the easternmost and most isolated outcrops of the Austroalpine basement of the Eastern Alps. Ar/Ar and K/Ar dating of phengitic mica indicates that the Eoalpine high-pressure metamorphism of the area occurred between 76 and 71 Ma. Short-lived metamorphism is characterized by fluid-poor conditions. Fluid circulation was mostly restricted to shear zones, thus the degree of Alpine overprint has an extreme spatial variation. In several metamorphic slices Variscan mineral assemblages have been preserved and biotite yielded Variscan and Permo-Triassic Ar ages. Different mineral and isotope thermometers (literature data) yielded temperatures of 500-600 o C for the peak of Alpine metamorphism in the Sopron Mountains, but muscovite and biotite do not show complete argon resetting. Thus, we consider this crystalline area as a well constrained natural test site, which either indicates considerably high closure temperatures (around 550 o C) for Ar in muscovite and biotite in a dry metamorphic environment, or which is suitable for testing the widely applied methods of temperature estimations under disequilibrium conditions. Apatite fission track results and their thermal modeling, together with structural, mineralogical and sedimentological observations, allows the identification of a post-metamorphic, Eocene hydrothermal event and Late Miocene-Pliocene sediment burial of the crystalline rocks of the Sopron Mountains. (author)

Stress and strain patterns, kinematics and deformation mechanisms in a basement-cored anticline: Sheep Mountain Anticline, Wyoming

Science.gov (United States)

Amrouch, Khalid; Lacombe, Olivier; Bellahsen, Nicolas; Daniel, Jean-Marc; Callot, Jean-Paul

2010-02-01

In order to characterize and compare the stress-strain record prior to, during, and just after folding at the macroscopic and the microscopic scales and to provide insights into stress levels sustained by folded rocks, we investigate the relationship between the stress-strain distribution in folded strata derived from fractures, striated microfaults, and calcite twins and the development of the Laramide, basement-cored Sheep Mountain Anticline, Wyoming. Tectonic data were mainly collected in Lower Carboniferous to Permian carbonates and sandstones. In both rock matrix and veins, calcite twins recorded three different tectonic stages: the first stage is a pre-Laramide (Sevier) layer-parallel shortening (LPS) parallel to fold axis, the second one is a Laramide LPS perpendicular to the fold axis, and the third stage corresponds to Laramide late fold tightening with compression also perpendicular to the fold axis. Stress and strain orientations and regimes at the microscale agree with the polyphase stress evolution revealed by populations of fractures and striated microfaults, testifying for the homogeneity of stress record at different scales through time. Calcite twin analysis additionally reveals significant variations of differential stress magnitudes between fold limbs. Our results especially point to an increase of differential stress magnitudes related to Laramide LPS from the backlimb to the forelimb of the fold possibly in relation with motion of an underlying basement thrust fault that likely induced stress concentrations at its upper tip. This result is confirmed by a simple numerical model. Beyond regional implications, this study highlights the potential of calcite twin analyses to yield a representative quantitative picture of stress and strain patterns related to folding.

Petrography and geochemistry of rocks from the sor-rondane mountains, droning Maude land, eastern Antarctica

International Nuclear Information System (INIS)

Rehman, S.S.; Shah, M.T.; Jan, M.Q.; Majid, M.

1999-01-01

Mamyu rock specimens, were collected from the sor-rondane mountains and Breid Bay area of Drojnning Maud land, eastern Antarctica, during the 2nd Pakistan Antarctic Expedition, 1992-93. Petrography and geochemical studies suggest that the rocks are essentially of igneous origin. The samples dredged from ocean bottom include olivine basalt, amygdaloidal volcanics, dacites and rhyodacites. A majority of these rocks are calc-alkaline and formed by the fraction of olivine, clinopyroxene and plagioclase +- titanomagnetite. Most of these rocks apparently formed in an island arc or continental margin set up. However, volcanics showing ocean floor basalt character are also present. A metamorphosed and deformed basement consisting of amphibolites, calc-silicate rocks and gneisses is intrude by under formed or only slightly deformed granites with a minor arkosic sandstone cover. The granites are chemically distinguished as I-type, originate at deeper crystal level by collisional/subduction related processes during organic environments. (author)

Rb-Sr geochronology of the rocks of the Himalayas, Eastern Nepal, (1)

International Nuclear Information System (INIS)

Kai, Kunio

1981-01-01

Rb-Sr isotopic measurements were carried out for whole rock and small sliced rock from the Himalayan gneiss which constitutes the metamorphosed basement of the Tethyan sediments. The results of the measurements on whole rock from the Barun migmatite, the Barun gneiss and the Irkhua gneiss indicate that complete Sr isotopic redistribution occurred about 520 m.y. ago. This age is interpreted as the time of the regional metamorphism. The analytical results of the small sliced slabs of the Himalayan gneiss indicate that Sr isotopic redistribution occurred among the sliced slabs 33.3 +- 13.2 m.y. ago. This age is interpreted as the time of the metamorphism in the sillimanite-amphibolite facies. The high initial 87 Sr/ 86 Sr ratio of 0.7372 +- 0.0031 from the Barun migmatite of the Himalayan gneiss suggests the Precambrian Origin of the source rocks. The analytical results on the sliced slab of the Barun migmatite indicate that the original age of the rocks is about 800 m.y. The rock is interpreted as the remobilized Precambrian crustal rock. The high initial 87 Sr/ 86 Sr ratio of the Barun gneiss and the Irkhua gneiss of the Himalayan gneiss (0.7234 +- 0.0013) indicates also the Precambrian origin of the source rocks. (author)

2.9-1.9 Ga paleoalterations of Archean granitic basement of the Franceville basin (Gabon)

Science.gov (United States)

Mouélé, Idalina Moubiya; Dudoignon, Patrick; El Albani, Abderrazak; Meunier, Alain; Boulvais, Philippe; Gauthier-Lafaye, François; Paquette, Jean-Louis; Martin, Hervé; Cuney, Michel

2014-09-01

The Archean granitoids in the Kiéné area, Gabon, are overlained by the Paleoproterozoic sediments of the Franceville basin (2.1 Ga). The basin is known for its high-grade uranium deposits among which some have been forming natural nuclear fission reactors. Most of the studies were dedicated to the FA-FB Paleoproterozoic sediments hosting these uranium deposits. Little is known on the Archean basement itself and specifically on the hydrous alteration events it experienced before and after the sediment deposition. The present work is focused on their petrographical, mineralogical and geochemical characterization. Dating the successive alteration events has been attempted on altered monazite crystals. Rocks in different alteration states have been sampled from eight drill cores crosscutting the Archean - Paleoproterozoic unconformity. The Archean granitoids observed in the deepest levels exhibit typical petrographical features of a propylitic alteration while they are intensely illitized up to the unconformity. The propylitic alteration is mainly pervasive but the original texture of the granitoïds is conserved in spite of the formation of new minerals: Mg-chlorite, allanite and epidote forming a typical paragenesis. The illitic alteration is much more invasive near the unconformity. The illitization process leads to the replacement of feldspars and the corrosion of quartz crysals by an illitic matrix while the ferromagnesian minerals are pseudomorphosed by a Fe-chlorite + phengite + hematite assemblage. The final fluid-rock interaction step is marked by fissural deposits of calcite and anhydrite. The δ13C isotopic data show that the fissural carbonates precipitated from diagenetic fluids enriched carbon products deriving from the maturation of organic matter. The U-Pb isotopic analyzes performed on monazite crystals have dated three distinct events: 3.0-2.9 Ga (magmatic), 2.6 Ga (propylitic alteration) and 1.9 Ga (diagenetic illitization). The calculation of

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...

A feasibility study on the expected seismic AVA signatures of deep fractured geothermal reservoirs in an intrusive basement

International Nuclear Information System (INIS)

Aleardi, Mattia; Mazzotti, Alfredo

2014-01-01

The deep geothermal reservoirs in the Larderello-Travale field (southern Tuscany) are found in intensively fractured portions of intrusive/metamorphic rocks. Therefore, the geothermal exploration has been in search of possible fracture signatures that could be retrieved from the analysis of geophysical data. In the present work we assess the feasibility of finding seismic markers in the pre-stack domain which may pinpoint fractured levels. Thanks to the availability of data from boreholes that ENEL GreenPower drilled in the deep intrusive basement of this geothermal field, we derived the expected amplitude versus angle (AVA) responses of the vapour reservoirs found in some intensely, but very localized, fractured volumes within the massive rocks. The information we have available limit us to build 1D elastic and isotropic models only and thus anisotropy effects related to the presence of fractures cannot be properly modelled. We analysed the velocities and the density logs pertaining to three wells which reached five deep fractured zones in the basement. The AVA response of the fractured intervals is modelled downscaling the log data to seismic scale and comparing the analytical AVA response (computed with the Aki and Richards approximation) and the AVA extracted from a synthetic common mid point (calculated making use of a reflectivity algorithm). The results show that the amplitude of the reflections from the fractured level is characterized by negative values at vertical incidence and by decreasing absolute amplitudes with the increase of the source to receiver offset. This contrasts with many observations from hydrocarbon exploration in clastic reservoirs where gas-sand reflections often exhibit negative amplitudes at short offsets but increasing absolute amplitudes for increasing source to receiver offsets. Thereby, some common AVA attributes considered in silicoclastic lithologies would lead to erroneous fracture localization. For this reason we propose a

Preliminary study of the physico-chemical and hydrodynamical characteristics of the crystalline basement aquifer of the Ihorombe region (south of Madagascar)

International Nuclear Information System (INIS)

Rakotoaridera, Z.S.

2008-04-01

The hydrochemical, hydrogeological and isotopic data have been used to determine the chemical and hydrodynamical characteristics of crystalline basement aquifer of the Ihorombe region. The study area is located in the District of Ihosy, which is about 600 km in the south of Antananarivo along the national road 7. Two types of aquifer have been found in this area: a phreatic aquifer composed of alterd metamorphic rocks, and a semi confined aquifer, which flows in a fissured and fractured rocks such as gneiss, and leptinites.The ground water mineralization is controlled by HCO 3- , Ca 2+ , Na + , Cl - . The dominant hydrochemical types of water in the study area are calcium and sodium bicarbonate. Some water samples show chloride types. The groundwater mineralization process is especially due to water rock interaction. The ground water is directly recharged by rain water. For the phreatic aquifer, the tritium values have provide a mean resident time less than 50 years, and for the semi confined aquifer, it is approximately above 100 years. [fr

U-Pb SHRIMP and Sm-Nd geochronology of the Silvânia Volcanics and Jurubatuba Granite: juvenile Paleoproterozoic crust in the basement of the Neoproterozoic Brasília Belt, Goiás, central Brazil

Directory of Open Access Journals (Sweden)

FISCHEL DANIELLE P.

2001-01-01

Full Text Available U-Pb SHRIMP and Sm-Nd isotopic ages were determined for felsic metavolcanic rocks from the Silvânia Sequence and Jurubatuba Granite in the central part of the Brasília Belt. Zircon grains from a metavolcanic sample yielded 2115 ± 23 Ma and from the granite yielded 2089 ± 14 Ma, interpreted as crystallization ages of these rocks. Six metavolcanic samples of the Silvânia Sequence yielded a six-point whole-rock Sm-Nd isochron indicating a crystallization age of 2262 ± 110 Ma and positive epsilonNd(T = +3.0 interpreted as a juvenile magmatic event. Nd isotopic analyses on samples from the Jurubatuba Granite have Paleoproterozoic T DM model ages between 2.30 and 2.42 Ga and epsilonNd(T values vary between -0.22 and -0.58. The oldest T DM value refers to a sedimentary xenolith in the granite. These results suggest crystallization ages of Silvânia volcanics and Jurubatuba Granite are the first evidence of a ca. 2.14-2.08 juvenile magmatic event in the basement of the central part of the Brasília Belt that implies the presence of arc/suture hidden in reworked basement of the Brasília Belt.

Experiments on pollutant transport from soil into residential basements by pressure-driven airflow

International Nuclear Information System (INIS)

Nazaroff, W.W.; Lewis, S.R.; Doyle, S.M.; Moed, B.A.; Nero, A.V.

1987-01-01

At two residences in Portland, OR, they have investigated (1) the coupling between residential basements and the air in nearby soil and (2) the influence of basement depressurization on the migration of air in soil. With the basements depressurized 25-50 Pa relative to outdoor air, underpressures as great as 20-40% of those in the basement were observed at sampling points in the soil. Sulfur hexafluoride was injected into the soil near the houses and its concentration monitored in soil air and in the house over time, both with and without basement depressurization. Depressurization was seen to have a substantial effect on the migration of the tracer within the soil. For basement depressurizations of 25-50 Pa, effective transport velocities through the soil and into the houses were observed to exceed 1 m h -1 . Airborne 222 Rn concentration was monitored in the basement of one house during the 6-day investigation and was seen to increase substantially on each of the seven occasions that the house was depressurized. The techniques employed are applicable to the study of problems of excessive radon entry into buildings and the migration of toxic vapors from waste dumps and landfills

Experiments performed on a man-made crack in the flat low-permeability basement as a basis for large-scale technical extraction of terrestrial heat

Energy Technology Data Exchange (ETDEWEB)

Kappelmeyer, O.; Jung, R.; Rummel, F.

1984-01-01

Research work is performed on an in-situ experimental field in the crystalline subsoil near Falkenberg in East Bavaria which are to help develop new technologies for exploiting geothermal energy. The aim is to make terrestrial heat available for technical utilization even with a relatively normal geologic structure of the subsoil - i.e. far away from volcanos and outside of layers carrying water or steam. To achieve this objective, artificial heat exchange systems were produced by hydraulic fracturing of crystalline rocks at a depth of 250 m. Geometric positions of these cracks were located by means of seismic and geo-electric methods. Seismic observations allowed deriving a crack model which helped with penetrating the man-made crack by sectional drilling. The circulation system consisting in production drill-hole, crack system and sectional drill-hole was studied for hydraulic parameter (e.g. flow resistance) and thermal efficiency at various pressure levels in the crack. Crack width was measured at different pressure stages for the first time. Thermal model calculations allow transferral of the results gained from the flat relatively cool basement to basement areas of an elevated temperature. A number of rock parameters which are relevant for an assessment whether or not the subsoil is suitable for creating artificial heat exchange systems, were examined on-site and bench-scale.

Mouse endometrial stromal cells produce basement-membrane components

DEFF Research Database (Denmark)

Wewer, U M; Damjanov, A; Weiss, J

1986-01-01

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. The dec......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....... 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....

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

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

Examination of the Basement of Historic Buildings in Investment Activity

Directory of Open Access Journals (Sweden)

Ulybin Aleksey

2016-01-01

Full Text Available The process and methodology of the survey of basements rarely mentioned in the various construction rules and regulations. Basically describes the procedure of conducting a detailed survey of some of the individual elements. These surveys are fundamental in nature, include a large number of estimates and require significant financial and time costs. Usually the purpose of these surveys is to check the state of the building as a whole, it’s safe operation or before starting of reconstruction. In the process of selecting areas of investment activity such large-scale survey is not possible. Needed a quick and inexpensive method intended for decision about investment in a particular object. At the same time, the survey should cover all the elements of the basement significantly affect the cost of reconstruction of the basement associated with his penetration. The article presents the general conception of conducting a rapid survey. The described methods and technologies applicable to the examination for the purpose of making decisions about investments in reconstruction of a basement level rooms. The composition of the works and their sequence. A comparison of the advantages and disadvantages of different methods. The practical examples. Scheme of conducting a rapid survey of the basement. The article analyzes the materials used in the construction of historic buildings in St. Petersburg.

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

A study based on trace elements of differentiated metabasic rocks from the Machado-MG region

International Nuclear Information System (INIS)

Choudhuri, A.; Carvalho, S.G. de.

1983-01-01

Large metabasic intrusive bodies occur in the Precambrian gneiss-migmatite basement around Poco Fundo - Campestre - Machado Triangle, south Minas Gerais. Separate occurrences consisting in each case of pyroxenite, metagabbro and amphibolite seem to be related to each other as is evident from their mineralogy, texture and trends of trace element concentration when plotted against their mg number (Mg/MgO + FeO mol.). Furthermore, their trace elements indicate that these rocks belong to a differentiated sequence resulting from separation of pyroxenes in situ. In spite of their high large ion lithophile element contents comparable to calc-alcaline rocks, the metabasic rocks show close resemblance to present-day mid-ocean ridge basalts when these are plotted in relevant variation diagrams. The tectonic implication of the observations is, however, not yet clear. (Author) [pt

The basement of the Punta de Este Terrane: A meso proterozoic heritage at the eastern border of Rio de La Plata craton

International Nuclear Information System (INIS)

Preciozzi, F.; Peel, E.; Sanchez, L.; Basei, M.

2005-01-01

U-Pb zircon ages between 1000 and 900 Ma corresponding to the nuclei of zircon crystals extracted from the basement of the Punta del Este Terrane (Eastern Uruguay) allowed the correlation of the protoliths of this domain with rocks attributed to the Namaqua Belt in Southwestern Africa. SHRIMP ages obtained for the ortho gneissic rocks allowed to place at ca. 750 Ma the generations of gneisses and migmatites. Differently from what occurred in Africa, reworking of this crustal segment during the Brasiliano-Pan african orogenesis was very intense, reaching the granulite facies around 640Ma. Acid volcanic and volcaniclastic rocks (Sierra de Aguirre Formation) with ages around 570 Ma, late sedimentary basins (San Carlos Formation) and post-tectonic granitoids (Santa Teresa and José Ignacio batholith s) mark the end of the events related with the Brasiliano/Pan-African orogenesis. The final collision between the Punta del Este Terrane and the western domains represented by the Dom Feliciano Belt and the Río de La Plata Craton may have occurred at around 535 Ma

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.

Hydrochemical characterization and quality evaluation of groundwater in parts of the basement complex area of ekiti, southwestern nigeria

International Nuclear Information System (INIS)

Ojo, T.A.; Niyi, T.M.

2013-01-01

Well water (88 samples) were collected across various bedrock units in the basement terrain of Ekiti area, Southwestern Nigeria. They were subjected to in-situ physico-chemical measurement and hydrochemical analyses using lC-OES and ion-chromatography methods for cations and anions, respectively. To understand the water quality and utilisation aspects of groundwater, chemical indices like sodium %, sodium adsorption ratio (SAR), Wilcox diagram and salinity diagram were constructed based on the analytical results. The results show pH values ranging between 6.0-7.8 and total hardness (TH) 3.2-508.7 mg/L. Major cations concentrations were in the order of Ca2 >K/sup +/>Na >Mg with average values of 28.5, 26.8, 24.2 and 7.9 mg/L, respectively while that of the anions were HCO >Cl >SO/sub 4/sup 2/ >NO/sub 3/ with average values of 118.7, 54.2, 23.8 and 0.92 mg/L. The main hydrochemical facies being Ca-HCO/sub 3/ waters. The ionic orders of abundance varied in different rocks of the study area. These concentration trends show a low total dissolved solids (130-1544 microS/cm) indicating a low water-rock interaction due to low residence time which is an indication of CO/sub 2/ dominated infiltration recharge with limited migratory history typical of the shallow basement terrain in the study area. Quality assessment revealed a potable groundwater system with chemical parameters within the acceptable limits of the WHO and SON drinking water standards with exception of Fe, Mn and Pb in a couple of locations. Also, the estimated SAR alongside TDS revealed a shallow groundwater system suitable for irrigation purpose. (author)

Origin of the ca. 50 Ma Linzizong shoshonitic volcanic rocks in the eastern Gangdese arc, southern Tibet

Science.gov (United States)

Liu, An-Lin; Wang, Qing; Zhu, Di-Cheng; Zhao, Zhi-Dan; Liu, Sheng-Ao; Wang, Rui; Dai, Jin-Gen; Zheng, Yuan-Chuan; Zhang, Liang-Liang

2018-04-01

The origin of the Eocene shoshonitic rocks within the upper part of the extensive Linzizong volcanic succession (i.e., the Pana Formation) in the Gangdese arc, southern Tibet remains unclear, inhibiting the detailed investigations on the crust-mantle interaction and mantle dynamics that operate the generation of the coeval magmatic flare-up in the arc. We report mineral composition, zircon U-Pb age and zircon Hf isotope, whole-rock element and Sr-Nd-Hf isotope data for the Pana Formation volcanic rocks from Pangduo, eastern Gangdese arc in southern Tibet. The Pana volcanic rocks from Pangduo include basalts, basaltic andesites, and dacites. SIMS and LA-ICPMS zircon U-Pb dating indicates that the Pangduo dacites were erupted at 50 ± 1 Ma, representing the volcanic equivalent of the coeval Gangdese Batholith that define a magmatic flare-up at 51 ± 1 Ma. The Pangduo volcanic rocks are exclusively shoshonitic, differing from typical subduction-related calc-alkaline volcanic rocks. The basalts have positive whole-rock ƐNd(t) (+1.7) and ƐHf(t) (+3.8) with high Zr abundances (121-169 ppm) and Zr/Y ratios (4.3-5.2), most likely derived from the partial melting of an enriched garnet-bearing lithospheric mantle that was metasomatized by subduction-related components with input from asthenosphere. Compared to the basalts, similar trace elemental patterns and decreased whole-rock ƐNd(t) (-3.5 to -3.3) and ƐHf(t) (-2.5 to -1.6) of the basaltic andesites can be attributed to the input of the ancient basement-derived material of the central Lhasa subterrane into the basaltic magmas. The coherent whole-rock Sr-Nd-Hf isotopic compositions ((87Sr/86Sr)i = 0.7064-0.7069, ƐNd(t) = -6.0 to -5.2, ƐHf(t) = -5.6 to -5.0) and varying zircon ƐHf(t) (-6.0 to +4.1) of the dacites can be interpreted by the partial melting of a hybrid lower crust source (juvenile and ancient lower crust) with incorporation of basement-derived components. Calculations of zircon-Ti temperature and whole-rock

development in a basement terrain

African Journals Online (AJOL)

2004-05-17

May 17, 2004 ... especially as a reconnaissance tool (de Jong et al., 1981; de. Rooy et al., 1986; ... ful naval radio transmitters in the very low frequency range. (15-25kHz). ... involved partial curve matching and computer iteration tech- niques. .... result predicted depth to fresh basement bedrock to be 46m whilst drilling ...

Effects of pressure and electrical charge on macromolecular transport across bovine lens basement membrane.

Science.gov (United States)

Ferrell, Nicholas; Cameron, Kathleen O; Groszek, Joseph J; Hofmann, Christina L; Li, Lingyan; Smith, Ross A; Bian, Aihua; Shintani, Ayumi; Zydney, Andrew L; Fissell, William H

2013-04-02

Molecular transport through the basement membrane is important for a number of physiological functions, and dysregulation of basement membrane architecture can have serious pathological consequences. The structure-function relationships that govern molecular transport in basement membranes are not fully understood. The basement membrane from the lens capsule of the eye is a collagen IV-rich matrix that can easily be extracted and manipulated in vitro. As such, it provides a convenient model for studying the functional relationships that govern molecular transport in basement membranes. Here we investigate the effects of increased transmembrane pressure and solute electrical charge on the transport properties of the lens basement membrane (LBM) from the bovine eye. Pressure-permeability relationships in LBM transport were governed primarily by changes in diffusive and convective contributions to solute flux and not by pressure-dependent changes in intrinsic membrane properties. The solute electrical charge had a minimal but statistically significant effect on solute transport through the LBM that was opposite of the expected electrokinetic behavior. The observed transport characteristics of the LBM are discussed in the context of established membrane transport modeling and previous work on the effects of pressure and electrical charge in other basement membrane systems. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

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 characterization of core protein-specific monoclonal antibodies (MAb) against a chondroitin sulfate proteoglycan (CSPG) present in Reichert's membrane, a transient extra-embryonic structure of rodents. This CSPG was also demonstrated to be present in adult rat kidney. We report here the tissue distribution...... of epitopes recognized by these MAb. The ubiquitous presence of these epitopes in the basement membranes of nearly all adult rat tissues demonstrates that at least one CSPG is a constituent of most basement membranes, and by virtue of its unique distribution is distinct from other chondroitin and dermatan...

Movement of fossil pore fluids in granite basement, Illinois

International Nuclear Information System (INIS)

Couture, R.A.; Seitz, M.G.

1986-01-01

The compositions of pore fluids in granite cores from the Precambrian basement in northern Illinois were determined. The estimated chloride concentration in the aqueous phase increases from near zero at the upper contact with sandstone to 2.7 M at 624 m below the contact. Traces of aliphatic oil are present in the overlying sandstone and the upper 516 m of granite, and oil occupies most of the pore space in one sample of unaltered granite 176 m below the contact. The oil has a Δ 13 C of -25%, about the same as average petroleum. The high concentrations of salt more than 500 m below the contact imply that little or no fresh water has reached these levels of the granite by flow. Lower concentrations near the contact are consistent with replacement of brine in the sandstone by fresh water at least 11 m.y. ago and subsequent upward diffusion of salt from the granite. Geologic data suggest that the time of replacement was about 130 Ma. The purpose of the investigation is to study the record of movement of intergranular fluids within a granite pluton. The composition and movement of ground waters can determine the extent that hazardous or radioactive wastes disposed in igneous rock will remain isolated

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.

A Brief History With Lessons Learned From The Hot Dry Rock Geothermal Energy Program At Fenton Hill, New Mexico, USA

Science.gov (United States)

Kelkar, S.; Woldegabriel, G. W.; Rehfeldt, K. R.

2009-12-01

Important lessons were learned that continue to be relevant today from the world’s first successful demonstration of a Hot Dry Rock (HDR) system for extracting underground geothermal energy conducted at Fenton Hill, New Mexico. This experiment, conducted in hot, low-permeability, low-water context, crystalline basement rock was fundamentally different from the Enhanced Geothermal Systems (EGS) development currently underway at several sites in the U.S. and world. The HDR concept was developed in 1970’s at Los Alamos National Laboratory (LANL). Two HDR reservoirs with two wells each were created and tested at the Fenton Hill site. In spite of its proximity to the Valles caldera and the Rio Grande rift, geological information and heat-flow data were used successfully to select the Fenton Hill experimental site within a block of intact crystalline basement rocks. Deep crystalline basement rocks marginal to active fault/recent volcanic centers were good candidates for HDR systems: these rocks had high heat content, and low matrix permeability leading to low water losses. Reconnaissance surveys indicated significant potential HDR geothermal resources through out the USA. Drilling and completion operations in hot crystalline rocks were challenging requiring further R&D. Hydraulic stimulation activities were carried out successfully in deep, hot crystalline rocks. Logging tools and instruments were developed that could operate successfully in the ~250oC environment. Development of techniques and tools for microseismic data monitoring, analysis, and interpretation was found to be enormously valuable. It was found that the systematic process that should be followed in developing HDR reservoirs is to drill and stimulate the first well, use the microseismic data to locate the target zone, and then complete the additional wells. The largest fraction of the flow impedance was found to be near the production well. Combined interpretation of the pressure testing, microseismic

Paleoproterozoic mojaveprovince in northwestern Mexico? Isotopic and U-Pb zircon geochronologic studies of precambrian and Cambrian crystalline and sedimentary rocks, Caborca, Sonora

Science.gov (United States)

Lang, Farmer G.; Bowring, S.A.; Matzel, J.; Maldonado, G.E.; Fedo, C.; Wooden, J.

2005-01-01

Whole-rock Nd isotopic data and U-Pb zircon geochronology from Precambrian crystalline rocks in the Caborca area, northern Sonora, reveal that these rocks are most likely a segment of the Paleoproterozoic Mojave province. Supporting this conclusion are the observations that paragneiss from the ??? 1.75 Ga Bamori Complex has a 2.4 Ga Nd model age and contains detrital zircons ranging in age from Paleo- proterozoic (1.75 Ga) to Archean (3.2 Ga). Paragneisses with similar age and isotopic characteristics occur in the Mojave province in southern California. In addition, "A-type" granite exposed at the southern end of Cerro Rajon has ca 2.0 Ga Nd model age and a U-Pb zircon age of 1.71 Ga, which are similar to those of Paleoproterozoic granites in the Mojave province. Unlike the U.S. Mojave province, the Caborcan crust contains ca. 1.1 Ga granite (Aibo Granite), which our new Nd isotopic data suggest is largely the product of anatexis of the local Precambrian basement. Detrital zircons from Neoproterozoic to early Cambrian miogeoclinal arenites at Caborca show dominant populations ca. 1.7 Ga, ca. 1.4 Ga, and ca. 1.1 Ga, with subordinate Early Cambrian and Archean zircons. These zircons were likely derived predominately from North American crust to the east and northeast, and not from the underlying Caborcan basement. The general age and isotopic similarities between Mojave province basement and overlying miogeoclinal sedimentary rocks in Sonora and southern California is necessary, but not sufficient, proof of the hypothesis that Sonoran crust is allochthonous and was transported to its current position during the Mesozoic along the proposed Mojave-Sonora megashear. One viable alternative model is that the Caborcan Precambrian crust is an isolated, autochthonous segment of Mojave province crust that shares a similar, but not identical, Proterozoic geological history with Mojave province crust found in the southwest United States ?? 2005 Geological Society of America.

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

Applications of aeromagnetic data to detect the Basement Tectonics of Eastern Yemen region

Directory of Open Access Journals (Sweden)

Ahmed S. Abu El-Ata

2013-12-01

Full Text Available The present study aims to throw light on the tectonic implications concerned with the distribution of the sedimentary sequence belts and the related basement complex zones, as well as to differentiate between the causative sources (contacts, dykes and faults of Eastern Yemen region. The total intensity aeromagnetic map of the study area was first corrected by the application of the Reduction To the magnetic pole (for low latitude areas. The visual inspection of the RTP magnetic map defines a rapid change in the subsurface geologic conditions in the form of lithologic characters and tectonic inferences. On the other hand, this map showed different anomalies of varying frequencies and amplitudes that revealed various causative sources, as well as varying compositions and depths. At the interpretation stage, various techniques and software tools are available for extracting the geologic information from the data concerned. The magnetic fields of shallow sources can be separated from those of deeper causatives, using two processes known as power spectrum transformation and matched band pass filtering. Three methods for locating magnetic sources (Magnitude of Horizontal Gradients (HGM, the analytical signals (AS and the local wavenumbers (LW in three dimensions and identifying the properties of their sources indicated that, the area was affected by some intrusions at various depths in sill or dyke forms, almost oriented in the NW–SE, NE–SW, E–W and N–S trends. Tectonically, the area is highly affected by the tectonics related to the Arabian Sea, Gulf of Aden and Red Sea. It is affecting both the basement and sedimentary rocks, dividing the study area into several faulted blocks.

Geochronological data for lithostratigraphic complexes of a crystalline basement from the South regions of Minas Gerais and adjacent areas of the Sao Paulo state

International Nuclear Information System (INIS)

Kawashita, K.; Artur, A.C.; Wernick, E.

1988-01-01

New geochronological data (Rb/Sr, Pb/Pb) for the Amparo and Pinhal Complexes, southern State of Minas Gerais and adjacent areas of the State of Sao Paulo are presented and discussed with respect to other lithostratigraphic complexes which there occur. Among the different complexes considered, 4 are composed mainly by rock belonging to typical infrastructure associations. They are the Barcelona, the Guaxupe, the Amparo and the Pinhal complexes. The Barbacena Complex is a typical gray gneiss complex and geochronological data by different methods confirm its Archean age. The Guaxupe Complex is composed mainly by different types of charnockitic rocks and an Archean age is assumed on geotectonic basis due to its neighboring association with the gray gneiss/greenstone belt, a though confirming geochronological data are still missing, a normal feature in this type of mobile belts which generally show a complex, polycyling evolution. Geochronological data by different methods on diverse rock types indicates that the Amparo and Pinhal complexes are respectively of Lower an Upper proterozoic age. Geochronological, geological and petrographic data reveal that both complexes are composed mainly by 3 basic rock associations: a-mainly derived magmatic rocks including mafic/ultramafic ones as well as calc-alkaline, subalcaline and even alkaline granitoids; b-orthogneisses, migmatites and crustal granites derived by metamorphic processes acting on older, pre-existing rocks; corthogneisses and migmatites resulting from metamorphic processes acting on magmatic rocks intruded during the same tecto-metamorphic cycle during which its transformation took place. The results suggest a polycyclic evolution by successive tecto-metamorphic events which affected the older rocks of the considered are either by the reworking of enclosing rocks around pericratonic continental main magmatic arcs or by the remobilisation of older basement rocks during continental collisions. (author) [pt

The First Evidence of the Precambrian Basement in the Fore Range Zone of the Great Caucasus.

Science.gov (United States)

Latyshev, A.; Kamzolkin, V.; Vidjapin, Y.; Somin, M.; Ivanov, S.

2017-12-01

Within the Great Caucasus fold-thrust belt, the Fore Range zone has the most complicated structure, and the highest degree of metamorphism was found there. This zone consists of several salients with the different composition and the structural and metamorphic evolution. The largest Blyb salient includes the metamorphic basement covered by the pack of thrusts. According to the recent isotopic data the upper levels of the Blyb metamorphic complex (BMC) are supposed to be Middle-Paleozoic (Somin, 2011). We studied zircons from the granitic intrusions located in the metamorphic rocks of the BMC. The U-Pb dating (SHRIMP II, VSEGEI, Russia) of zircons from the large Balkan metadiorite massif yielded the ages of 549±7,4, 574,1±6,7, and 567,9±6,9 Ma. All studied zircons show the high Th/U ratios and likely have the magmatic origin. This data is the first confirmation of the presence of the Precambrian basement and Vendian magmatic activity in the Fore Range zone. Zircons from the Unnamed granodiorite massif from the south of the Blyb salient yielded the age of 319±3.8 Ma (the Early Carboniferous). This fact taken together with the low grade of metamorphism in this intrusion reveals the Late Paleozoic magmatic event in the Fore Range zone. We also suggest that the Precambrian basement of the BMC, including the Balkan intrusion, is covered by so-called Armovsky nappe. This is confirmed by the field data, Middle-Paleozoic U-Pb ages and the higher degree of metamorphism of the Armovsky gneisses and schists. Thus, the BMC is not uniform but includes the blocks of the different age and metamorphic grades. Finally, we measured the anisotropy of magnetic susceptibility (AMS) of the Balkan metadiorites. The axes of AMS ellipsoid fix the conditions of the north-east compression, as well as the strain field reconstructed from the macrostructures orientation, which corresponds to the thrusts propagation. Therefore, the emplacement of the Balkan massif happened before the thrust

Major and minor elements and traces in igneous rocks from crystalline basement of Parana by X-ray fluorescence; Elementos maiores, menores e tracos, em rochas igneas do escudo cristalino paranaense por fluorescencia de raios-X

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Ademar O.; Pecequilo, Brigitte R.S.; Scapin, Marcos A.; Salvador, Vera L.R., E-mail: aoferreira@ipen.br, E-mail: brigitte@ipen.br, E-mail: mascapin@ipen.br, E-mail: vsalvado@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Major and minor components of 30 acid and basic igneous rocks (granites, syenites, riolites and a basalt) of the Parana state crystalline basement were determined by X-ray fluorescence spectrometry (WDXRF), in order to evaluate the similarity in terms of the compositional content. The corrections of interelements effects (absorption/intensification) were performed by means of the fundamental parameters (FP) method. The methodology was validated using a certificated reference material. The main oxides found associated with the quantified elements are SiO{sub 2}, Al{sub 2}O{sub 3}, Na{sub 2}O, K{sub 2}O, Fe{sub 2}O{sub 3}, CaO, MgO, TiO{sub 2}, P{sub 2}O{sub 5}, MnO, SO{sub 3}, NiO, ZnO, Rb{sub 2}O. Through statistical analysis, the studied samples were organized in 3 groups of similar compositions: syenites, light granites and basalt and dark granites. The results show that the WDXRF technique is a robust tool that enables distinction even between similar geological samples. (author)

The modelling and measurement of super-conducting rock joints

International Nuclear Information System (INIS)

Barton, N.; Makurat, A.; Vik, G.; Loset, F.

1985-01-01

Rock joints exhibiting exceptionally high conductivity have been responsible for severe inflows (10-50 m 3 /min.) and flooding in recent Norwegian tunneling projects. These events may be explained by channeling of flow in partially outwashed mineral fillings, associated with deep weathering in ancient basement rocks. There is also evidence to suggest extensional strain with consistent relationships to regional faulting patterns (Selmer-Olsen 1981). Hydraulic fractures making connection with joint systems that are sheared as a result of increased fluid pressure, has been deduced as the mechanism explaining unusually large fluid losses in the geothermal project in Cornwall, England (Pine and Batchelor, 1984). Such mechanisms also introduce uncertainty into water flood and MHF stimulation treatment of fractured oil and gas reservoirs, particularly when principal stress and joint orientations are poorly understood due to coring and stress measurement problems in weak, overstressed reservoir rocks. The possibility of permanent disposal of nuclear waste in crystalline rock, has also focussed attention on highly conductive (''super-conducting'') joints in nuclear waste programmes in Canada, the USA and in Europe. The bi-modal distributions of joint spacing, continuity, apertures and conductivities resulting from the discovery of super-conducting joints has important implications for the location of planned repositories, due to their dramatic impact on potential transport times. In the laboratory a class of super-conducting joints can be created by shear displacement that causes dilation when shearing non-planar features. Recent biaxial shear testing of rock joints recovered in jointed core has identified a strong coupling of conductivity and shear displacement. The theoretical predictions of constitutive relationships for coupled flow in rock joints (Barton et al. 1985) have been broadly verified

Geochemistry of Precambrian sedimentary rocks used to solve stratigraphical problems: An example from the Neoproterozoic Volta basin, Ghana

DEFF Research Database (Denmark)

Kalsbeek, F.; Frei, Robert

2010-01-01

The Neoproterozoic Volta basin of Ghana (not, vert, similar115,000 km2; depth up to 5–7 km) consists of flat-lying sedimentary rocks, mainly sandstones that unconformably overlie the crystalline basement of the West-African craton. The stratigraphical column has been subdivided into three main...... and Obosum Groups is used to solve one of the outstanding controversies regarding the stratigraphy of the Volta basin....

3D depth-to-basement and density contrast estimates using gravity and borehole data

Science.gov (United States)

Barbosa, V. C.; Martins, C. M.; Silva, J. B.

2009-05-01

We present a gravity inversion method for simultaneously estimating the 3D basement relief of a sedimentary basin and the parameters defining the parabolic decay of the density contrast with depth in a sedimentary pack assuming the prior knowledge about the basement depth at a few points. The sedimentary pack is approximated by a grid of 3D vertical prisms juxtaposed in both horizontal directions, x and y, of a right-handed coordinate system. The prisms' thicknesses represent the depths to the basement and are the parameters to be estimated from the gravity data. To produce stable depth-to-basement estimates we impose smoothness on the basement depths through minimization of the spatial derivatives of the parameters in the x and y directions. To estimate the parameters defining the parabolic decay of the density contrast with depth we mapped a functional containing prior information about the basement depths at a few points. We apply our method to synthetic data from a simulated complex 3D basement relief with two sedimentary sections having distinct parabolic laws describing the density contrast variation with depth. Our method retrieves the true parameters of the parabolic law of density contrast decay with depth and produces good estimates of the basement relief if the number and the distribution of boreholes are sufficient. We also applied our method to real gravity data from the onshore and part of the shallow offshore Almada Basin, on Brazil's northeastern coast. The estimated 3D Almada's basement shows geologic structures that cannot be easily inferred just from the inspection of the gravity anomaly. The estimated Almada relief presents steep borders evidencing the presence of gravity faults. Also, we note the existence of three terraces separating two local subbasins. These geologic features are consistent with Almada's geodynamic origin (the Mesozoic breakup of Gondwana and the opening of the South Atlantic Ocean) and they are important in understanding

Boring and Sealing Rock with Directed Energy Millimeter-Waves

Science.gov (United States)

Woskov, P.; Einstein, H. H.; Oglesby, K.

2015-12-01

Millimeter-wave directed energy is being investigated to penetrate into deep crystalline basement rock formations to lower well costs and to melt rocks, metals, and other additives to seal wells for applications that include nuclear waste storage and geothermal energy. Laboratory tests have established that intense millimeter-wave (MMW) beams > 1 kW/cm2 can melt and/ or vaporize hard crystalline rocks. In principle this will make it possible to create open boreholes and a method to seal them with a glass/ceramic liner and plug formed from the original rock or with other materials. A 10 kW, 28 GHz commercial (CPI) gyrotron system with a launched beam diameter of about 32 mm was used to heat basalt, granite, limestone, and sandstone specimens to temperatures over 2500 °C to create melts and holes. A calibrated 137 GHz radiometer view, collinear with the heating beam, monitored real time peak rock temperature. A water load surrounding the rock test specimen primarily monitored unabsorbed power at 28 GHz. Power balance analysis of the laboratory observations shows that the temperature rise is limited by radiative heat loss, which would be expected to be trapped in a borehole. The analysis also indicates that the emissivity (absorption efficiency) in the radiated infrared range is lower than the emissivity at 28 GHz, giving the MMW frequency range an important advantage for rock melting. Strength tests on one granite type indicated that heating the rock initially weakens it, but with exposure to higher temperatures the resolidified black glassy product regains strength. Basalt was the easiest to melt and penetrate, if a melt leak path was provided, because of its low viscosity. Full beam holes up to about 50 mm diameter (diffraction increased beam size) were achieved through 30 mm thick basalt and granite specimens. Laboratory experiments to form a seal in an existing hole have also been carried out by melting rock and a simulated steel casing.

Mapping magnetic lineaments and subsurface basement beneath ...

Indian Academy of Sciences (India)

65

studied the basement structures beneath parts of the Lower Benue Trough (LBT). Anudu et .... order vertical derivatives can be calculated respectively using the relations below: 145. ( ) ... minerals as in the case of the FVD-RTP-TMI (Figure 6).

Reactor-building-basement radionuclide and source distribution studies. Volume 3

International Nuclear Information System (INIS)

Cox, T.E.; Horan, J.T.; Worku, G.

1983-06-01

The Three Mile Island Unit 2 (TMI-2) Reactor Building basement has been sampled several times since August 1979. This report compiles the analytical results and sample history for the liquid and solid samples obtained to date. In addition, basement radiation levels were also obtained using thermoluminescent dosimeters (TLDs). The data obtained will provide information to support ongoing mass balance and source term studies and will aid in characterizing the 282-ft elevation for decontamination planning and dose reduction

A Sr-isotopic comparison between thermal waters, rocks, and hydrothermal calcites, Long Valley caldera, California

Science.gov (United States)

Goff, F.; Wollenberg, H.A.; Brookins, D.C.; Kistler, R.W.

1991-01-01

The 87Sr/86Sr values of thermal waters and hydrothermal calcites of the Long Valley caldera geothermal system are more radiogenic than those of young intracaldera volcanic rocks. Five thermal waters display 87Sr/86Sr of 0.7081-0.7078 but show systematically lighter values from west to east in the direction of lateral flow. We believe the decrease in ratio from west to east signifies increased interaction of deeply circulating thermal water with relatively fresh volcanic rocks filling the caldera depression. All types of pre-, syn-, and post-caldera volcanic rocks in the west and central caldera have (87Sr/86Sr)m between about 0.7060 and 0.7072 and values for Sierra Nevada granodiorites adjacent to the caldera are similar. Sierran pre-intrusive metavolcanic and metasedimentary rocks can have considerably higher Sr-isotope ratios (0.7061-0.7246 and 0.7090-0.7250, respectively). Hydrothermally altered volcanic rocks inside the caldera have (87Sr/86Sr)m slightly heavier than their fresh volcanic equivalents and hydrothermal calcites (0.7068-0.7105) occupy a midrange of values between the volcanic/plutonic rocks and the Sierran metamorphic rocks. These data indicate that the Long Valley geothermal reservoir is first equilibrated in a basement complex that contains at least some metasedimentary rocks. Reequilibration of Sr-isotope ratios to lower values occurs in thermal waters as convecting geothermal fluids flow through the isotopically lighter volcanic rocks of the caldera fill. ?? 1991.

Modeling radon entry into houses with basements: Model description and verification

International Nuclear Information System (INIS)

Revzan, K.L.; Fisk, W.J.; Gadgil, A.J.

1991-01-01

We model radon entry into basements using a previously developed three-dimensional steady-state finite difference model that has been modified in the following ways: first, cylindrical coordinates are used to take advantage of the symmetry of the problem in the horizontal plant; second, the configuration of the basement has been made more realistic by incorporating the concrete footer; third, a quadratic relationship between the pressure and flow in the L-shaped gap between slab, footer, and wall has been employed; fourth, the natural convection of the soil gas which follows from the heating of the basement in winter has been taken into account. The temperature field in the soil is determined from the equation of energy conservation, using the basement, surface, and deep-soil temperatures as boundary conditions. The pressure field is determined from Darcy's law and the equation of mass conservation (continuity), assuming that there is no flow across any boundary except the soil surface (atmospheric pressure) and the opening in the basement shell (fixed pressure). After the pressure and temperatures field have been obtained the velocity field is found from Darcy's law. Finally, the radon concentration field is found from the equation of mass-transport. The convective radon entry rate through the opening or openings is then calculated. In this paper we describe the modified model, compare the predicted radon entry rates with and without the consideration of thermal convection, and compare the predicted rates with determined from data from 7 houses in the Spokane River valley of Washington and Idaho. Although the predicted rate is much lower than the mean of the rates determined from measurements, errors in the measurement of soil permeability and variations in the permeability of the area immediately under the basement slab, which has a significant influence on the pressure field, can account for the range of entry rates inferred from the data. 25 refs., 8 figs

Expression of basement membrane components through morphological changes in the hair growth cycle

DEFF Research Database (Denmark)

Couchman, J R; Gibson, W T

1985-01-01

The amount and distribution of fibronectin associated with hair follicles was found to vary during the hair growth cycle in the rat. Immunocytochemical staining of follicles in mid-late anagen (the growth stage) revealed the presence of fibronectin in the dermal papilla matrix, in the basement...... membrane separating this from the epithelial cells of the hair bulb, and in the basement membrane and connective tissue sheath which underly the cells of the outer root sheath. Early in catagen, the transitional stage, staining of the dermal papilla matrix disappeared. Fibronectin persisted in the basement...

Stratigraphy of Slick Rock district and vicinity, San Miguel and Dolores Counties, Colorado

Science.gov (United States)

Shawe, Daniel R.; Simmons, George C.; Archbold, Norbert L.

1968-01-01

The Slick Rock district covers about 570 square miles in western San Miguel and Dolores Counties, in southwestern Colorado. It is at the south edge of the salt-anticline region of southwestern Colorado and southeastern Utah and of the Uravan mineral belt.Deposition of Paleozoic sedimentary rocks in the district and vicinity was principally controlled by development of the Paradox Basin, and of Mesozoic rocks by development of a depositional basin farther west. The Paleozoic rocks generally are thickest at the northeast side of the Paradox Basin in a northwest- trending trough which seems to be a wide graben in Precambrian igneous and metamorphic basement rocks; Mesozoic rocks generally thicken westward and southwestward from the district.Sedimentary rocks rest on a Precambrian basement consisting of a variety of rocks, including granite and amphibolite. The surface of the Precambrian rocks is irregular and generally more than 2,000 feet below sea level and 7,000-11,000 feet below the ground surface. In the northern part of the district the Precambrian surface plunges abruptly northeastward into the trough occupying the northeast side of the Paradox Basin, and in the southern part it sags in a narrow northeasterly oriented trough. Deepening of both troughs, or crustal deformation in their vicinity, influenced sedimentation during much of late Paleozoic and Mesozoic time.The maximum total thickness of sedimentary rocks underlying the district is 13,000 feet, and prior to extensive erosion in the late Tertiary and the Quaternary it may have been as much as about 18,000 feet. The lower 5,000 feet or more of the sequence of sedimentary rocks consists of arenaceous strata of early Paleozoic age overlain by dominantly marine carbonate rocks and evaporite beds interbedded with lesser amounts of clastic sediments of late Paleozoic age. Overlying these rocks is about 4,500 feet of terrestrial clastic sediments, dominantly sandstone with lesser amounts of shale, mudstone

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.

Co-deposition of basement membrane components during the induction of murine splenic AA amyloid

DEFF Research Database (Denmark)

Lyon, A W; Narindrasorasak, S; Young, I D

1991-01-01

Past studies have demonstrated that during murine AA amyloid induction there is co-deposition of the AA amyloid peptide and the basement membrane form of heparan sulfate proteoglycan. The synthesis and accumulation of heparan sulfate proteoglycan does not usually occur in the absence of other...... basement membrane components, such as type IV collagen, laminin, and fibronectin. Using immunohistochemical techniques, the present experiments have demonstrated that in addition to the heparan sulfate proteoglycan, there are other basement membrane components present in splenic AA amyloid deposits...... and these are present as soon as AA amyloid deposits are detectable. The results indicate that within the time constraints imposed by the experiments, the basement membrane components, fibronectin, laminin, type IV collagen, and heparan sulfate proteoglycan are co-deposited 36 to 48 hours after the AgNO3 and amyloid...

Basement membrane chondroitin sulfate proteoglycan alterations in a rat model of polycystic kidney disease

DEFF Research Database (Denmark)

Ehara, T; Carone, F A; McCarthy, K J

1994-01-01

of distal tubules and collecting ducts was observed by 4 days with phenol II treatment, but the morphology returned to normal after 7 days of subsequent normal diet. Staining of tissue sections with two mouse monoclonal antibodies to a recently described basement membrane chondroitin sulfate proteoglycan...... to chondroitin sulfate chains confirmed these changes in cystic tubule basement membranes. During the recovery stage, interstitial chondroitin sulfate (representing a CSPG other than BM-CSPG) was greatly increased around these tubules, along with the glycoprotein fibronectin. Staining with antibody to a basement...... membrane heparan sulfate proteoglycan core protein related to perlecan did not diminish but rather stained affected tubules intensely, whereas laminin, on the other hand, was apparently diminished in the basement membranes of the cystic tubules. Type IV collagen staining did not change through disease...

Rock strength measurements on Archaean basement granitoids recovered from scientific drilling in the active Koyna seismogenic zone, western India

Science.gov (United States)

Goswami, Deepjyoti; Akkiraju, Vyasulu V.; Misra, Surajit; Roy, Sukanta; Singh, Santosh K.; Sinha, Amalendu; Gupta, Harsh; Bansal, B. K.; Nayak, Shailesh

2017-08-01

Reservoir triggered earthquakes have been occurring in the Koyna area, western India for the past five decades. Triaxial tests carried out on 181 core samples of Archaean granitoids underlying the Deccan Traps provide valuable constraints on rock strength properties in the Koyna seismogenic zone for the first time. The data include measurements on granite gneiss, granite, migmatitic gneiss and mylonitised granite gneiss obtained from boreholes KBH-3, KBH-4A, KBH-5 and KBH-7 located in the western and eastern margins of the seismic zone. Salient results are as follows. (i) Increase of rock strength with increasing confining pressure allow determination of the linearized failure envelopes from which the cohesive strength and angle of internal friction are calculated. (ii) Variable differential stresses at different depths are the manifestations of deformation partitioning in close association of fault zone(s) or localized fracture zones. (iii) Fractures controlled by naturally developed weak planes such as cleavage and fabric directly affect the rock strength properties, but the majority of failure planes developed during triaxial tests is not consistent with the orientations of pre-existing weak planes. The failure planes may, therefore, represent other planes of weakness induced by ongoing seismic activity. (iv) Stress-strain curves confirm that axial deformation is controlled by the varying intensity of pre-existing shear in the granitoids, viz., mylonite, granite gneiss and migmatitic gneiss. (v) Frequent occurrences of low magnitude earthquakes may be attributed to low and variable rock strength of the granitoids, which, in turn, is modified by successive seismic events.

Provenance of zircon of the lowermost sedimentary cover, Estonia, East-European Craton

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Konsa, M.

1999-12-01

Full Text Available Bulk and accessory mineral composition of fresh and weathered crystalline rocks, and sedimentary deposits overlying the crystalline-sedimentary unconformity have been examined in core samples from 28 drill holes in Estonia. Before the Late Vendian to Early Cambrian regional subsidence and sedimentation, the region represented a flat plateau within the Svecofennian Domain. Palaeo-and Mesoproterozoic crystalline rocks, regardless their different initial mineral composition, subcrop under the Upper Vendian/Lower Cambrian sedimentary cover as usually intensely weathered rocks (saprolites composed of residual quartz, altered micas and prevailing clay minerals mainly of the kaolinite group. Thus, the bulk mineral composition of any basement crystalline rocks imparts no specific inherited rock-forming minerals into the covering sedimentary rocks. From the variety of accessory and opaque minerals of crystalline rocks, only zircon populations survived in saprolites. Crystalline rocks of different origin yield different zircons. Relationships between the zircon typology of the basement rocks having specific areas of distribution and the sedimentary rocks immediately overlying those crystalline rocks were the main subject of this study. The result is that siliciclastic sedimentary rocks covering weathered crystalline rocks only in places inherited zircons with typological features characteristic of specific basement areas. In northeastern Estonia, local lenses of the Oru Member (the earliest Upper Vendian sedimentary rocks in Estonia resembling the debris of weathered crystalline rocks yield accessory zircon which in a 1-2 m thick layer above the basement surface is similar to the zircons of the underlying weathering mantle of certain crystalline rocks. In the next unit, the Moldova Member, up to 43 m above the basement surface, a mixture of zircons resembling those of various local basement rocks has been found. Further upwards, in the Vendian and Lower

Gravimetric survey and modeling of the basement morphology in the sedimentary thickness characterization, NE portion of Paraná Sedimentary Basin - Brazil

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Maximilian Fries

2017-05-01

Full Text Available ABSTRACT: The northeast portion of the Paraná Sedimentary Basin is distinguished by structural highs as the known Pitanga Dome, an uplifted structure identified in the last century. It represents a geological and evolutionary evidence of the Paraná Sedimentary Basin and has undergone inspired studies and intense exploration surveys. This study consists of a gravimetric survey in the Pitanga Dome area, State of São Paulo, Brazil. The Bouguer gravity anomalies have been identified and related to the structural high, sedimentary thickness, and the basement morphology. Processing and enhancement techniques were used for forward modeling based on previous studies. The three models from profiles sectioning the dome have a sedimentary thickness varying from 200 to 1.250 meters. The adopted methodology has provided important results determining that the Pitanga Dome can be understood through rational 3D visualization. The area can be interpreted as an undulating basement with thinning of sedimentary rocks related to deep features (structures in the crust/mantle limit (Moho uplift. This characteristic is confirmed by the sedimentary layer thickening present throughout the surrounding area. The results also offer important insights and support for further studies concerning the genesis and evolution of this and other uplifted structures of the Paraná Sedimentary Basin.

Some results from the demonstration of indoor radon reduction measures in block basement houses. Report for June 1985-February 1987

International Nuclear Information System (INIS)

Henschel, D.B.; Scott, A.G.

1987-03-01

The paper gives results of tests of active soil-ventilation techniques in 24 block-wall basement houses in eastern Pennsylvania having significantly elevated indoor radon concentrations, generally above 740 Bq/cu m. The results indicate that radon levels can be reduced substantially (often below the U.S. EPA guideline of 148 Bq/cu m) if effective suction can be drawn on the soil underneath the concrete slabs of these houses. Such effective suction appears achievable when either: (a) the house has a complete loop of drain tile around its footings for water drainage purposes, and suction is drawn on that loop; or (b) a sufficient number of suction pipes can be inserted at the proper locations into the crushed rock or soil underneath the slab

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.

Review of potential host rocks for radioactive waste disposal in the Piedmont Province of Georgia

International Nuclear Information System (INIS)

Wenner, D.B.; Gillon, K.A.

1980-10-01

A literature study was conducted on the Piedmont province of Georgia to designate areas that may be favorable for field exploration for consideration of a repository for storage of radioactive waste. The criteria utilized in such a designation was based upon consideration of the rock unit having favorable geological, geotechnical, and geohydrological features. The most important are that the rock unit have: (1) satisfactory unit dimensions (> 100 km 2 outcrop area and at least 1500 meters (approx. 5000 feet) depth of a continuous rock type); and (2) acceptable geohydrological conditions. Among all rock types, it is concluded that the granites of the large post-metamorphic plutons and large, homogeneous orthogneissic units offer the most favorable geologic settings for exploration for siting a radioactive waste repository. Virtually all other rock types, including most metavolcanic and metasedimentary lithologies have unacceptable unit dimensions, generally unfavorable geohydrologic settings, and deleterious mechanical and physical geotechnical properties. After consideration of all major lithologies that comprise the Georgia Piedmont, the following units were deemed favorable: (1) the Elberton Pluton; (2) the Siloam Pluton; (3) the Sparta Pluton; (4) two unnamed plutons adjacent to the Snelson body of S.W. Georgia; (5) the Lithonia Gneiss; (6) basement orthogneisses and charnockites of the Pine Mountain Belt

Basement radon entry and stack driven moisture infiltration reduced by active soil depressurization

Science.gov (United States)

C.R. Boardman; Samuel V. Glass

2015-01-01

This case study presents measurements of radon and moisture infiltration from soil gases into the basement of an unoccupied research house in Madison, Wisconsin, over two full years. The basement floor and exterior walls were constructed with preservative-treated lumber and plywood. In addition to continuous radon monitoring, measurements included building air...

Geology and zircon fission track ages of volcanic rocks in the western part of Hoshino gold area, Fukuoka Prefecture, Japan

Energy Technology Data Exchange (ETDEWEB)

Belhadi, Ahmed; Himeno, Osamu; Watanabe, Koichiro; Izawa, Eiji [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

1999-12-01

The Hoshino gold area is located in the western part of the Hohi volcanic zone, northern Kyushu. Volcanic rocks in this area vary from andesitic rocks in the north to dacite and rhyolite in the South. The basement is constituted by metamorphic rocks of pre-Cretaceous age. The volcanic rocks of Pliocene age were subdivided into eight volcanic units. Seven fission track ages of zircons from five volcanic units have been determined, using the external detector method. The age data obtained, combined with some previously reported ages, show that two main volcanic activities have occurred in the area. The first volcanic activity took place around 4.3 Ma, and resulted into the deposition of the Hoshino Andesite and the Ikenoyama Conglomerate. The second main volcanism started around 3.5 Ma, and was characterized by the eruption of the Shakadake Andesite and the Reiganji Andesite at the early stage, then, by more acidic rocks of the Takeyama Andesite, the Hyugami Dacite and the Kuroki Rhyolite at the later stage. The main volcanism in the area ceased around 2.6 Ma. (author)

Indoors and health: results of a systematic literature review assessing the potential health effects of living in basements.

Science.gov (United States)

Mezzoiuso, Angelo Giosué; Gola, Marco; Rebecchi, Andrea; Riccò, Matteo; Capolongo, Stefano; Buffoli, Maddalena; Tirani, Marcello; Odone, Anna; Signorelli, Carlo

2017-10-23

A new law approved in March 2017 in the Lombardy Region makes it possible to live in basements. Basements are defined as buildings partly below curb level but with at least one-half of its height above the curb. Basements' features and structural characteristics might pose risks to human health. In this paper we adopt a multidisciplinary approach to assess the potential health effects of living in basements. In particular, we define a conceptual framework to describe basements' structural characteristics which are risk factors, as well as the mechanisms through which they impact on human health. We also conduct a systematic review on the scientific databases PubMed,Embase, DOAJ, Proquest and EBSCO to retrieve, pool and critically analyze all available research that quantified the risk of living in basements for different health outcomes. Available evidence suggests living in basements increases the risk of respiratory diseases (asthma and allergic disorders); more heterogeneous data are available for cancers and cardiovascular diseases. As more quantitative data need to be prospectively retrieved to assess and monitor the risk of living in basements for human health, clear minimum requirements for light, air, sanitation and egress are to be defined by technical experts and enforced by policy makers.

Anti-glomerular basement membrane disease superimposed on membranous nephropathy: a case report and review of the literature

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Nivera Noel

2010-08-01

Full Text Available Abstract Introduction Anti-glomerular basement membrane disease is a rare autoimmune disorder characterized by pulmonary hemorrhage, crescentic glomerulonephritis and the presence of circulating anti-glomerular basement membrane antibodies. The simultaneous occurrence of both anti-glomerular basement membrane disease and membranous nephropathy is rare. Case presentation A 59-year-old Hispanic man presented with acute onset of nausea and vomiting and was found to have renal insufficiency. Work-up included a kidney biopsy, which revealed anti-glomerular basement membrane disease with underlying membranous nephropathy. He was treated with emergent hemodialysis, intravenous corticosteroids, plasmapheresis, and cyclophosphamide without improvement in his renal function. Conclusion Simultaneous anti-glomerular basement membrane disease and membranous nephropathy is very rare. There have been 16 previous case reports in the English language literature that have been associated with a high mortality and morbidity, and a very high rate of renal failure resulting in hemodialysis. Co-existence of membranous nephropathy and anti-glomerular basement membrane disease may be immune-mediated, although the exact mechanism is not clear.

The Amazon-Laurentian connection as viewed from the Middle Proterozoic rocks in the central Andes, western Bolivia and northern Chile

Science.gov (United States)

Tosdal, R.M.

1996-01-01

between these cratons and seemingly precluding part of the Arequipa-Antofalla craton from being a detached fragment of another craton such as eastern Laurentia, which has been characterized by a different U/Pb history. Pb isotopic compositions for the Arequipa-Antofalla craton are, furthermore, distinct from those of the Proterozoic basement in the Precordillera terrane, western Argentina, indicating a Pb isotopic and presumably a tectonic boundary between them. The Pb isotopic compositions for the Precordillera basement are similar to those of eastern Laurentia, and support other data indicating that these rocks are a detached fragment of North America. Finally, the distinct Pb isotopic evolution history of the Arequipa-Antofalla craton and eastern Laurentia require minor modification to tectonic models linking eastern North America-Scotland to the oroclinal bend in western South America.

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.

Analyses of about 6000 km of processed magnetic data in the central Bay of Bengal using Analytical Signal Processing and Werner Deconvolution techniques revealed that the depth to top of the magnetic basement varies between 5 and 12 km from the sea...

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.

Geochemical characterization of Parana Basin volcanic rocks: petrogenetic implications

International Nuclear Information System (INIS)

Marques, L.S.

1988-01-01

A detailed study of the geochemical characteristics of Parana Basin volcanic rocks is presented. The results are based on the analyses of major and trace elements of 158 samples. Ninety three of these volcanic samples belong to 8 flow sequences from Rio Grande do Sul and Santa Catarina States. The remaining sixty five samples are distributed over the entire basin. In order to study the influence of crustal contamination processes in changing chemical characteristics of the volcanic rocks, 47 samples representative of the crystalline basement of the southern and southeastern Parana Basin were also analysed. Several petrogenetic models were tested to explain the compocional variability of the volcanic rocks, in particular those of southern region. The results obtained sugest an assimilation-fractional crystallization process as viable to explain the differences of both the chemical characteristics and Sr isotope initial ratios observed in basic and intermediate rocks. A model involving melting processes of basic material, trapped at the base of the crust, with composition similar to low and high TiO 2 basalts appears to be a possibility to originate the Palmas and Chapeco acid melts, respectively. The study of ''uncontaminated'' or poorly contaminated low TiO 2 basic rocks from the southern, central and northern regions shows the existence of significant differences in the geochemical charactetistics according to their geographical occurrence. A similar geochemical diversity is also observed in high TiO 2 basalts and Chapeco volcanics. Differences in incompatible element ratios between low and high TiO 2 ''uncontaminated'' or poorly contaminated basalts suggest that they could have been produced by different degrees of melting in a garnet peridotite source. Geochemical and isotopic (Sr and Nd) data also support the view that basalts from northern and southern regions of Parana Basin originated from mantle source with different composition. (author) [pt

Characterizing nanoscale topography of the aortic heart valve basement membrane for tissue engineering heart valve scaffold design.

Science.gov (United States)

Brody, Sarah; Anilkumar, Thapasimuthu; Liliensiek, Sara; Last, Julie A; Murphy, Christopher J; Pandit, Abhay

2006-02-01

A fully effective prosthetic heart valve has not yet been developed. A successful tissue-engineered valve prosthetic must contain a scaffold that fully supports valve endothelial cell function. Recently, topographic features of scaffolds have been shown to influence the behavior of a variety of cell types and should be considered in rational scaffold design and fabrication. The basement membrane of the aortic valve endothelium provides important parameters for tissue engineering scaffold design. This study presents a quantitative characterization of the topographic features of the native aortic valve endothelial basement membrane; topographical features were measured, and quantitative data were generated using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and light microscopy. Optimal conditions for basement membrane isolation were established. Histological, immunohistochemical, and TEM analyses following decellularization confirmed basement membrane integrity. SEM and AFM photomicrographs of isolated basement membrane were captured and quantitatively analyzed. The basement membrane of the aortic valve has a rich, felt-like, 3-D nanoscale topography, consisting of pores, fibers, and elevations. All features measured were in the sub-100 nm range. No statistical difference was found between the fibrosal and ventricular surfaces of the cusp. These data provide a rational starting point for the design of extracellular scaffolds with nanoscale topographic features that mimic those found in the native aortic heart valve basement membrane.

Vascular basement membranes as pathways for the passage of fluid into and out of the brain.

Science.gov (United States)

Morris, Alan W J; Sharp, Matthew MacGregor; Albargothy, Nazira J; Fernandes, Rute; Hawkes, Cheryl A; Verma, Ajay; Weller, Roy O; Carare, Roxana O

2016-05-01

In the absence of conventional lymphatics, drainage of interstitial fluid and solutes from the brain parenchyma to cervical lymph nodes is along basement membranes in the walls of cerebral capillaries and tunica media of arteries. Perivascular pathways are also involved in the entry of CSF into the brain by the convective influx/glymphatic system. The objective of this study is to differentiate the cerebral vascular basement membrane pathways by which fluid passes out of the brain from the pathway by which CSF enters the brain. Experiment 1: 0.5 µl of soluble biotinylated or fluorescent Aβ, or 1 µl 15 nm gold nanoparticles was injected into the mouse hippocampus and their distributions determined at 5 min by transmission electron microscopy. Aβ was distributed within the extracellular spaces of the hippocampus and within basement membranes of capillaries and tunica media of arteries. Nanoparticles did not enter capillary basement membranes from the extracellular spaces. Experiment 2: 2 µl of 15 nm nanoparticles were injected into mouse CSF. Within 5 min, groups of nanoparticles were present in the pial-glial basement membrane on the outer aspect of cortical arteries between the investing layer of pia mater and the glia limitans. The results of this study and previous research suggest that cerebral vascular basement membranes form the pathways by which fluid passes into and out of the brain but that different basement membrane layers are involved. The significance of these findings for neuroimmunology, Alzheimer's disease, drug delivery to the brain and the concept of the Virchow-Robin space are discussed.

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

Research on evolutionary laws of Sr, Nd, Pb isotopes of uranium metallization and volcanic rocks in south china

International Nuclear Information System (INIS)

Ying Junlong

1998-01-01

According to research on evolutionary tracer of Sr, Nd, Pb isotopes, the author proposes that isotopic evolution of Mesozoic volcanics in south China is controlled by regionally metamorphic rocks of ancient land basement, early reformed derivates and recycled continental crust. Isotopic composition of uranium metallization shows the characteristics of crust sources, and Yanshanian accretion of continental margin caused the crust movement such as magmatic activity in lower crust within continent, extension-down-faulting, etc., promoting the migration, enrichment and ore formation of uranium

Natural-basement ventilation as a radon-mitigation technique. Final report Jun 89-Feb 91

International Nuclear Information System (INIS)

Cavallo, A.; Gadsby, K.; Reddy, T.A.

1992-04-01

The report documents a study of natural basement ventilation in two research houses during both the summer cooling season and the winter heating season. (NOTE: Natural basement ventilation has always been recommended as a way to reduce radon levels in houses. However, its efficacy has never been documented. It has generally been assumed to be a very inefficient mitigation strategy since it was believed that dilution was the mechanism by which radon levels were reduced.) Ventilation rates, environmental and house operating parameters, and radon levels have been monitored; it can be concluded that natural ventilation can reduce radon levels two ways: (1) by simple dilution, and (2) although less obvious, by providing a pressure break that reduces basement depressurization and thus the amount of radon-contaminated soil gas drawn into the house. Thus, basement ventilation can be a much more effective mitigation strategy than was previously believed. It might be especially useful in houses with low radon concentrations (of the order of 10 pCi/L) or those with low levels that cannot be mitigated cost-effectively with conventional technology

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.

Analisis Risiko pada Proyek Pembangunan Parkir Basement Jalan Sulawesi Denpasar

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I Wayan Muka

2015-04-01

Full Text Available Construction of Basement Parking Sulawesi Road Denpasar is a government attempt to tackle congestion and parking problems in the city of Denpasar. This activity is highly correlated with the location of Badung Market. This study aims to identify risks arising, assess the level of acceptance of risk analysis, risk mitigation and ownership of dominant risk. The results showed 25 risks identified. Of the risks identified are 24 risk dominant with 5 risk category is unacceptable occurrence of accidents in the project, the landslide during basement excavation, the lack of security fence project that can cause accidents especially hazard fell during basement excavation, the damage caused by natural disasters and the workers were not using safety equipment. Additionally identified 19 risk category is undesirable, one acceptable risk category. Dominant risk is unacceptable risks do 11 mitigation measures such as building damage due to natural disasters (force majeure, which is also a risk with follow-up by reducing the risk that anticipated early preparing for disasters and transfer risk to another party by insuring the work to others. Ownership is the most dominant risk of the contractor. The parties should consider the risks unacceptable category and also should pay attention to the risks classified as undesirable.

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

to fluid-basement rock reactions led to the precipitation at around 450 °C of poorly-crystallized hydrothermal graphite. This graphite presents isotopic (δ13C - 30 to - 26‰ PDB) and morphological differences from the high-T metamorphic graphite (> 600 °C, - 29 to - 20‰ δ13C) derived from metamorphism of C-rich sedimentary material. The brittle structural reactivation and the related fluid migration and graphite precipitation were specifically focused within the shear zones and related damage zones. The brittle reactivation produced major changes in the petro-physical, mineralogical, and chemical characteristics of the structures and their damage zones. It especially increased the fracture paleoporosity and rock weakness toward the fault cores. These major late metamorphic modifications of the graphitic shear zones were likely key parameters favoring the enhanced reactivity of these basement zones under tectonic stress following deposition of the Athabasca Basin, and so controlled basinal brine movement at the basin/basement interface related to the formation of the unconformity-related uranium deposits. This relationship consequently readily explains the specific spatial relationships between unconformity-related U deposits and the ductile-brittle graphitic shear zones.

Use of natural basement ventilation to control radon in single family dwellings

International Nuclear Information System (INIS)

Cavallo, A.; Gadsby, K.; Reddy, T.A.

1992-01-01

Natural basement ventilation has always been recommended as a means of reducing radon levels in houses. However, its efficacy has never been documented. In these experiments, natural ventilation has for the first time been studied systematically in two research houses during both the summer cooling season and the winter heating season. Ventilation rates, environmental and house operating parameters, as well as radon levels, have been monitored. It can be definitely concluded from radon entry rate calculations that natural ventilation can reduce radon levels in two ways. The first is by simple dilution. The second is by reducing basement depressurization and thus the amount of radon-contaminated soil gas drawn into the structure. Therefore, basement ventilation can be an effective mitigation strategy under some circumstances. It might be especially useful in houses with low radon concentrations (of the order of 370 Bq m -1 ) or those with low levels and which cannot be mitigated cost-effectively with conventional technology. (Author)

Two dimentional modeling of subsurface structure over upper Benue ...

African Journals Online (AJOL)

The subsurface lithology obtained from 2D modelling of the residual field showed the presence of two lithological units. The sedimentary rock unit underlined by the basement rock consists of shales, sandstones, limestones, siltstones, clay and non-marine facies. The Basement rock units were composed of pegmatite, ...

A Case of Alport Syndrome with Posttransplant Antiglomerular Basement Membrane Disease despite Negative Antiglomerular Basement Membrane Antibodies by EIA Treated with Plasmapheresis and Intravenous Immunoglobulin

Directory of Open Access Journals (Sweden)

Sumiko I. Armstead

2013-01-01

Full Text Available Posttransplant antiglomerular basement membrane (anti-GBM disease occurs in approximately 5% of Alport patients and usually ends in irreversible graft failure. Recent research has focused on characterizing the structure of the anti-GBM alloepitope. Here we present a case of a 22-year-old male with end-stage renal disease secondary to Alport syndrome, with a previously failed renal allograft, who received a second deceased-donor kidney transplant. Six days after transplantation, he developed acute kidney injury. The serum anti-GBM IgG was negative by enzyme immunoassay (EIA. On biopsy, he had crescentic glomerulonephritis with linear GBM fixation of IgG. With further analysis by western blotting, we were able to detect antibodies to an unidentified protein from the basement membrane. This patient was treated with plasmapheresis twice per week and monthly intravenous immunoglobulin (IVIG for a total of five months. At the end of treatment, these unknown antibodies were no longer detected. His renal function improved, and he has not required dialysis. We conclude that anti-GBM disease in patients with Alport Syndrome may be caused by circulating antibodies to other components of the basement membrane that are undetectable by routine anti-GBM EIA and may respond to treatment with plasmapheresis and IVIG.

A Case of Alport Syndrome with Posttransplant Antiglomerular Basement Membrane Disease despite Negative Antiglomerular Basement Membrane Antibodies by EIA Treated with Plasmapheresis and Intravenous Immunoglobulin.

Science.gov (United States)

Armstead, Sumiko I; Hellmark, Thomas; Wieslander, Jorgen; Zhou, Xin J; Saxena, Ramesh; Rajora, Nilum

2013-01-01

Posttransplant antiglomerular basement membrane (anti-GBM) disease occurs in approximately 5% of Alport patients and usually ends in irreversible graft failure. Recent research has focused on characterizing the structure of the anti-GBM alloepitope. Here we present a case of a 22-year-old male with end-stage renal disease secondary to Alport syndrome, with a previously failed renal allograft, who received a second deceased-donor kidney transplant. Six days after transplantation, he developed acute kidney injury. The serum anti-GBM IgG was negative by enzyme immunoassay (EIA). On biopsy, he had crescentic glomerulonephritis with linear GBM fixation of IgG. With further analysis by western blotting, we were able to detect antibodies to an unidentified protein from the basement membrane. This patient was treated with plasmapheresis twice per week and monthly intravenous immunoglobulin (IVIG) for a total of five months. At the end of treatment, these unknown antibodies were no longer detected. His renal function improved, and he has not required dialysis. We conclude that anti-GBM disease in patients with Alport Syndrome may be caused by circulating antibodies to other components of the basement membrane that are undetectable by routine anti-GBM EIA and may respond to treatment with plasmapheresis and IVIG.

Rat hair follicle dermal papillae have an extracellular matrix containing basement membrane components

DEFF Research Database (Denmark)

Couchman, J R

1986-01-01

, to be replaced by synthesis of other components including type I and III collagens. It seems likely therefore that the dermal papilla cells in vivo synthesize a basement membrane type of extracellular matrix, although a contribution from epithelial, and in some cases capillary endothelial, cells cannot be ruled......Dermal papillae are small mesenchymally derived zones at the bases of hair follicles which have an important role in hair morphogenesis in the embryo and control of the hair growth cycle in postnatal mammals. The cells of the papilla are enmeshed in a dense extracellular matrix which undergoes...... extensive changes in concert with the hair cycle. Here it is shown that this matrix in anagen pelage follicles of postnatal rats contains an abundance of basement membrane components rather than dermal components such as interstitial collagens. In particular, type IV collagen, laminin, and basement membrane...

Natural radioactivity in some rocks employed as dimension and decorative stones in the Nigerian building industry.

Science.gov (United States)

Tubosun, I A; Tchokossa, P; Balogun, F A; Fasasi, M K; Ocan, O; Adesanmi, C A

2013-12-01

The natural radioactivity in some selected granites and allied rocks from the Basement Complex of Nigeria for use as dimension/decorative stones was measured by gamma-ray spectrometry. The average activity concentrations observed for the selected rock samples range from 9 to 124 Bq kg⁻¹; 13 to 60 Bq kg⁻¹ and 1360 to 2326 Bq kg⁻¹ for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. The mean radiological hazard indices were 121.62 nGy h⁻¹; 239.73 Bq kg⁻¹; 0.65 Bq kg⁻¹ and 0.77 Bq kg⁻¹ for the absorbed dose rate, radium equivalent, external hazard and internal hazard, respectively. The results obtained were examined on the basis of existing International recommended limits and compared with data on similar rocks from other parts of the world. The values obtained for the rocks, except one, were found to be lower than the values recommended for building materials, and the rocks are considered safe for use as decorative stones as defined by OECD criteria (NEA-OCED Nuclear Energy Agency Dose Constraints in Optimisation of Occupational Radiological Protection Report by NEA Group Experts, OCED, France (2011)). Results highlight the fact that, despite meeting certain suitability criteria such as colour, texture, etc., the radioactivity content of the rocks is another factor of importance for their continued application in the human environment/building industry.

Cdc42 expression in keratinocytes is required for the maintenance of the basement membrane in skin

DEFF Research Database (Denmark)

Wu, Xunwei; Quondamatteo, Fabio; Brakebusch, Cord

2006-01-01

, structure and number of hemidesomosomes were not significantly changed in the Cdc42 mutant skin compared with the control mice and no blister formation was observed in mutant skin. These data indicate that Cdc42 in keratinocytes is important for maintenance of the basement membrane of skin....... process, which requires directed secretion, deposition and organization of basement membrane components at the basal side of epithelial cells. In the current study, we analyzed the maintenance of skin basement membrane in mice with a keratinocyte-restricted deletion of the Cdc42 gene. In the absence...

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

We previously reported the presence of a basement membrane-specific chondroitin sulfate proteoglycan (BM-CSPG) in basement membranes of almost all adult tissues. However, an exception to this ubiquitous distribution was found in the kidney, where BM-CSPG was absent from the glomerular capillary......, the present study used light and electron microscopic immunohistochemistry to examine the distribution of BM-CSPG and basement membrane heparan sulfate proteoglycan (BM-HSPG) during prenatal and postnatal renal development in the rat. Our results show that the temporal and spatial pattern of expression of BM...

Testing of indoor radon-reduction techniques in basement houses having adjoining wings. Final report, August 1988-September 1989

International Nuclear Information System (INIS)

Messing, M.

1990-11-01

The report gives results of tests of indoor radon reduction techniques in 12 existing Maryland houses, with the objective of determining when basement houses with adjoining wings require active soil depressurization (ASD) treatment of both wings, and when treatment of the basement alone is sufficient. In five basement houses with adjoining slabs on grade, ASD treatment of both wings provided an incremental additional radon reduction of 0 to 5.2 pCi/L, compared to ASD treatment of either one of the slabs alone. However, basement-only treatment reduced radon to <4 pCi/L in all five houses. In six basement houses having adjoining crawl spaces, ASD treatment of both wings (including sub-liner depressurization of the crawl space) provided little additional reduction compared to basement-only treatment, when sub-slab communication was good. When communication was not good, treatment of both wings was required to achieve <4 pCi/L. Tests of one fully slab-on-grade house showed that, when there is good aggregate under the slab, a one-pipe sub-slab depressurization system can achieve <1-2 pCi/L, even when there are forced-air supply ducts under the slab

Basement configuration of KG offshore basin from magnetic anomalies

Indian Academy of Sciences (India)

of charnockites of neighbouring EGMB and onshore K–G basin areas indicates that EGMB geology. (charnockites ... Marine magnetic anomalies; offshore K–G basin; magnetic basement; extension of EGMB geology; continent– oceanic boundary. ..... of India; J. Australian Petroleum Exploration Association. 14 29–41.

Early paleozoic granitoids in the southern Vanoise basement: U-Pb geochronology of the Arpont meta-granite (Savoy, French Alps); Granitoides d`age paleozoique inferieur dans le socle de Vanoise meridionale: geochronologie U-Pb du metagranite de l`Arpont (Alpes de Savoir, France)

Energy Technology Data Exchange (ETDEWEB)

Bertrand, J.M. [Laboratoire de geodynamique des chaines alpines, LGCA-CISM, 73 - Le Bourget-du-Lac (France); Leterrier, J. [Centre de recherches petrographiques et geochimique, 54 - Vandoeuvre-les-Nancy (France)

1997-12-01

The U-Pb age of a meta-granite from southern Vanoise (Brianconnais` domain) at 479{+-} 4 Ma confirms hat the micaschists which dominate this pre-alpine basement are, at least, of Early Paleozoic age. The rare magmatic rocks occurring in Vanoise and showing alkaline affinities, may be compared to the orthogneisses belonging to the Cambrian-Ordovician extensional event well known in other parts of the Varican belt. (authors) 27 refs.

Subduction of Proterozoic to Late Triassic continental basement in the Guatemala suture zone: A petrological and geochronological study of high-pressure metagranitoids from the Chuacús complex

Science.gov (United States)

Maldonado, Roberto; Ortega-Gutiérrez, Fernando; Ortíz-Joya, Guillermo A.

2018-05-01

Many continental subduction complexes contain abundant granitic rocks coexisting with minor volumes of eclogite-facies rocks. Characterization of granitic protoliths is crucial to decipher the origin of subducted continental crust, whereas knowledge of its metamorphic evolution is required to constrain the mechanisms of burial and exhumation. In this work we present geochronological and petrological evidence that demonstrate the occurrence of a subducted Proterozoic to Late Triassic granitic basement in the Chuacús complex of central Guatemala. Metagranitoids exposed in this area are interlayered with eclogite and other high-pressure rocks, and their structure is considerably variable due to strain partitioning during deformation. Laser ablation-inductively coupled plasma-mass spectrometry U-Pb zircon data from two ferroan metagranites yield protolith crystallization ages of ca. 1.1 Ga and their trace-element abundances suggest an origin related to intraplate magmatism, while a high-silica, peraluminous metagranite is dated at 1.0 Ga and was probably originated by partial melting of a high-grade continental crust. On the other hand, two megacrystic to augen metagranitoids yield protolith crystallization ages of ca. 224 Ma, which are identical within errors to the protolith age of hosted eclogitic metabasites. Their high incompatible trace element abundances together with the observed spatial-temporal relationships with mafic protoliths suggest that Late Triassic bimodal magmatism in the Chuacús complex was probably originated in a within-plate setting. Regardless of their age or structure, the studied metagranites preserve evidences for high-pressure metamorphic equilibration, such as the occurrence of Ca-rich garnet (XCa up to 0.52) in association with phengite (Si contents of up to 3.4 pfu) and rutile. The integration of Zr-in-rutile thermometry and phengite barometry allows the peak metamorphic conditions to be constrained at 640-680 °C and 13 kbar. This

Geochronological dating in polycyclic rocks: alternative interpretation to data from Serido (RN-PB) Brazil

International Nuclear Information System (INIS)

McReath, I.; Sa, E.F.J. de

1979-01-01

Recent studies revealed a polycyclic history of deformation and metamorphism in the Serido, region, with a minimum of three regionally important events (F 1-3 ) the earliest of which is restricted to gneisses interpreted as basement (Caico Group). A relation between these phases and a complex series of granitic rocks is possible, the oldest generations (G 1-2 ) being gneissified. K/Ar ages normally reflect the regional uplift and other events toward the close of the Brasilian orogeny. Some of the older dates in the 700 - 1.400 m.y. range encountered in intrusives and metamophites may be due to parcial overprinting of earlier events. Reference Rb/Sr isochrons for widely dispersed G 3 granites need checking, but give creditable Brasilian ages. Rb/Sr studies of Serido Group metasediments show disequilibrium with a dispersion of points between a reference Brasilian isochron and one at 2.0 b.y. Parcial rejuvenation during the Brasilian orogeny of older rock series seems the best current explanation, although locally metasomatism may have had some influence, while some effect of initial disequilibrium may also be present. Gneisses yield Rb/Sr isochron ages of ca.2.7 and 1.9 b.y. Unpublished diagrams (B.B.B. Neves, written comm.) show a similar dispersion to that encountered for the Serido Group, and this might be explained in a similar fashion. It should be noted, however, that the distinction between high-grade cover, instrusive orthogneisses and basement is difficult, and that in these analyses some of the former gneisses could have been included. The possible existence of some event at ca.1.1 b.y needs verification. (author) [pt

Petrological and geochemical characterization of the plutonic rocks of the Sierra de La Aguada, Province of San Luis, Argentina: Genetic implications with the Famatinian magmatic arc

Directory of Open Access Journals (Sweden)

E. Cristofolini

2017-07-01

Full Text Available This study presents a synthesis on the geology of the crystalline complex that constitute the Sierra de la Aguada, San Luis province, Argentine, from an approach based on field relations, petrologic and structural features and geochemical characteristic. This mountain range exposes a basement dominated by intermediate to mafic calcalkaline igneous rocks and peraluminous felsic granitoids, both emplaced in low to medium grade metamorphic rocks stabilized under low amphibolite facies. All this lithological terrane has been grouped in the El Carrizal-La Aguada Complex. Field relations, petrographic characterization and geochemical comparison of the plutonic rocks from the study area with those belonging to the Ordovician Famatinian suit exposed in the Sierra Grande de San Luis, suggest a genetic and temporal relation linked to the development of the Famatinian magmatic arc.

Dissolution of biogenic ooze over basement edifices in the equatorial Pacific with implications for hydrothermal ventilation of the oceanic crust

Science.gov (United States)

Bekins, B.A.; Spivack, A.J.; Davis, E.E.; Mayer, L.A.

2007-01-01

Recent observations indicate that curious closed depressions in carbonate sediments overlying basement edifices are widespread in the equatorial Pacific. A possible mechanism for their creation is dissolution by fluids exiting basement vents from off-axis hydrothermal flow. Quantitative analysis based on the retrograde solubility of calcium carbonate and cooling of basement fluids during ascent provides an estimate for the dissolution capacity of the venting fluids. Comparison of the dissolution capacity and fluid flux with typical equatorial Pacific carbonate mass accumulation rates shows that this mechanism is feasible. By maintaining sediment-free basement outcrops, the process may promote widespread circulation of relatively unaltered seawater in the basement in an area where average sediment thicknesses are 300-500 m. The enhanced ventilation can explain several previously puzzling observations in this region, including anomalously low heat flux, relatively unaltered seawater in the basement, and aerobic and nitrate-reducing microbial activity at the base of the sediments. ?? 2007 The Geological Society of America.

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

Basement Membrane Type IV Collagen and Laminin: An Overview of Their Biology and Value as Fibrosis Biomarkers of Liver Disease.

Science.gov (United States)

Mak, Ki M; Mei, Rena

2017-08-01

Basement membranes provide structural support to epithelium, endothelium, muscles, fat cells, Schwann cells, and axons. Basement membranes are multifunctional: they modulate cellular behavior, regulate organogenesis, promote tissue repair, form a barrier to filtration and tumor metastasis, bind growth factors, and mediate angiogenesis. All basement membranes contain type IV collagen (Col IV), laminin, nidogen, and perlecan. Col IV and laminin self-assemble into two independent supramolecular networks that are linked to nidogen and perlecan to form a morphological discernable basement membrane/basal lamina. The triple helical region, 7S domain and NCI domain of Col IV, laminin and laminin fragment P1 have been evaluated as noninvasive fibrosis biomarkers of alcoholic liver disease, viral hepatitis, and nonalcoholic fatty liver disease. Elevated serum Col IV and laminin are related to degrees of fibrosis and severity of hepatitis, and may reflect hepatic basement membrane metabolism. But the serum assays have not been linked to disclosing the anatomical sites and lobular distribution of perisinusoidal basement membrane formation in the liver. Hepatic sinusoids normally lack a basement membrane, although Col IV is a normal matrix component of the space of Disse. In liver disease, laminin deposits in the space of Disse and codistributes with Col IV, forming a perisinusoidal basement membrane. Concomitantly, the sinusoidal endothelium loses its fenestrae and is transformed into vascular type endothelium. These changes lead to capillarization of hepatic sinusoids, a significant pathology that impairs hepatic function. Accordingly, codistribution of Col IV and laminin serves as histochemical marker of perisinusoidal basement membrane formation in liver disease. Anat Rec, 300:1371-1390, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Soil inertia and shallow basement envelope impact on cellar internal temperature

Directory of Open Access Journals (Sweden)

Naima Sakami

2016-06-01

Full Text Available This work deals with a three dimensional numerical study of heat transfer by conduction between the soil and the shallow basement in the city of Marrakech (Morocco. The heat transfer equation is solved by the finite difference method using the implicit alternative direction (ADI. The internal temperature of the cellar is computed by using energy balance equation in the cellar. The objective of this work is to evaluate the effects of the nature of the soil, the nature of the walls, the thickness of the walls of the cellar and the distance L far from the cellar on the internal temperature and the heat exchanged between the soil and the shallow basement

Regulation of the basement membrane by epithelia generated forces

Science.gov (United States)

Tanner, Kandice

2012-12-01

Tumor metastasis involves a progressive loss of tissue architecture and dissolution of structural boundaries between the epithelium and connective tissue. The basement membrane (BM), a specialized network of extracellular matrix proteins forms a barrier that physically restricts pre-invasive lesions such that they remain as local insults. The BM is not a static structure, but one that is constantly regenerated and remodeled in the adult organism. Matrix organization also regulates cell function. Thus alterations in the balance of synthesis, remodeling and proteolytic degradation of the extracellular matrix proteins may contribute to a loss of structural integrity. However, the de novo assembly and maintenance of the complex structural properties of in vivo basement membranes remain elusive. Here, this paper highlights the current understanding on the structural properties and the establishment of the BM, and discusses the potential role of self-generated forces in adult tissue remodeling and the maintenance of the BM as a malignancy suppressor.

Regulation of the basement membrane by epithelia generated forces

International Nuclear Information System (INIS)

Tanner, Kandice

2012-01-01

Tumor metastasis involves a progressive loss of tissue architecture and dissolution of structural boundaries between the epithelium and connective tissue. The basement membrane (BM), a specialized network of extracellular matrix proteins forms a barrier that physically restricts pre-invasive lesions such that they remain as local insults. The BM is not a static structure, but one that is constantly regenerated and remodeled in the adult organism. Matrix organization also regulates cell function. Thus alterations in the balance of synthesis, remodeling and proteolytic degradation of the extracellular matrix proteins may contribute to a loss of structural integrity. However, the de novo assembly and maintenance of the complex structural properties of in vivo basement membranes remain elusive. Here, this paper highlights the current understanding on the structural properties and the establishment of the BM, and discusses the potential role of self-generated forces in adult tissue remodeling and the maintenance of the BM as a malignancy suppressor. (paper)

Uranium mineralization by ground water in sedimentary rocks, Japan

International Nuclear Information System (INIS)

Doi, K.; Hirono, S.; Sakamaki, Y.

1975-01-01

To solve the mechanism of uranium concentration in stratabound uranium deposits occurring in the basal part of Neogene sediments overlying granite basement, attention was paid to uranium leaching from weathered granite by circulating carbonated fissure waters, to effective adsorbents for fixing uranium from uraniferous ground waters, to structural features controlling the ground-water circulation, and other relevant factors. The evidence for uranium transportation by hydothermal solutions, including hot spring waters, is hard to observe. Conclusions are summarized as follows: Uranium in the deposits is supplied from surrounding source rocks, mostly from granite. Uranium is transported by circulating ground-water solutions. The uranium dissolved in ground water is fixed in minerals in various ways, the most important being adsorption by carbonaceous matter. Ore-grade uranium concentrated from very dilute solutions occurs by multiple repetition of a leaching-and-fixation cycle between minerals or adsorbents and circulating uraniferous ground water. Important factors for uranium mineralization are sufficient uranium, supplied mostly from granite, the existence of effective adsorbents such as carbonaceous matter in the host rocks, and favorable geological, geochemical, and geophysical environments. The last seem to require not only physical and chemical conditions but also correct flow and volume of ground water. (U.S.)

Gravitational sliding of the Mt. Etna massif along a sloping basement

Science.gov (United States)

Murray, John B.; van Wyk de Vries, Benjamin; Pitty, Andy; Sargent, Phil; Wooller, Luke

2018-04-01

Geological field evidence and laboratory modelling indicate that volcanoes constructed on slopes slide downhill. If this happens on an active volcano, then the movement will distort deformation data and thus potentially compromise interpretation. Our recent GPS measurements demonstrate that the entire edifice of Mt. Etna is sliding to the ESE, the overall direction of slope of its complex, rough sedimentary basement. We report methods of discriminating the sliding vector from other deformation processes and of measuring its velocity, which averaged 14 mm year-1 during four intervals between 2001 and 2012. Though sliding of one sector of a volcano due to flank instability is widespread and well-known, this is the first time basement sliding of an entire active volcano has been directly observed. This is important because the geological record shows that such sliding volcanoes are prone to devastating sector collapse on the downslope side, and whole volcano migration should be taken into account when assessing future collapse hazard. It is also important in eruption forecasting, as the sliding vector needs to be allowed for when interpreting deformation events that take place above the sliding basement within the superstructure of the active volcano, as might occur with dyke intrusion or inflation/deflation episodes.

Petrology and geochemistry of the ~2.9 Ga Itilliarsuk banded iron formation and associated supracrustal rocks, West Greenland

DEFF Research Database (Denmark)

Haugaard, Rasmus; Frei, Robert; Stendal, Henrik

2013-01-01

unconformably on a basement of tonalite–trondhjemite–granodiorite (TTG) lithologies. Felsic metagreywackes, meta-semipelites and thinly bedded ferruginous shales were identified intercalated with the Itilliarsuk BIF. Other associated rocks include metapelites, acidic metavolcanics and metagabbroic sills.......29. The associated supracrustal rocks in the study area have significantly higher, positive ɛNd(i) values. The 143Nd/144Nd in the Itilliarsuk BIF, therefore, contrasts world BIFs by exhibiting radiogenic, positive ɛNd(i) values in shallow seawaters where the REY's were controlled by a local, depleted continental...... crust, whereas the negative ɛNd(i) values found in the iron-rich layers suggest that the submarine hydrothermal source was influenced by an enriched mantle, possibly an older subcontinental lithospheric segment. The felsic metagreywackes are immature, first-cycle (SiO2/Al2O3 ∼ 4.4, [La/Yb >> 1]CHON...

The Influence Of Hydrothermal Alteration And Weathering On Rock Magnetic Properties Of Granites From The Eps-1 Drilling (soultz-sous-forÊts / France)

Science.gov (United States)

Just, J.; Schleicher, A.; Kontny, A.; de Wall, H.

The EPS-1 drilling in Soultz-sous-Forêts (Rhinegraben, France) recovered a core pro- file of Tertiary to Permo-Mesozoic sediments deposited on a Variscan granitic base- ment. Magnetic susceptibility (k) measurements on the core material revealed a con- tinous increase from the basement/cover boundary (kmean 0.4 x 10-3 SI) into the magnetite-bearing granite (kmean 13 x 10-3 SI) over a depth range of 1417 U 1555 m. Rock magnetic and mineralogic studies were performed for the fresh granite, the hydrothermally altered granite near a fault zone and the altered granite from the fossil land surface near the basement/cover boundary. The decrease in susceptibility can be correlated with a gradual decomposition of magnetite to hematite and an alteration of the matrix minerals feldspars, biotite and hornblende to clay minerals and carbon- ates. Along with this transition, characteristic rock magnetic signatures can be dis- criminated for different degrees of alteration. While temperature-dependent magnetic susceptibility k(T)-curves in fresh granites indicate a typical multidomain magnetite course with good reversibility, different types of irreversible courses are observed for the altered granite. However, hematite could not be identified in the k(T)-curves. Al- tered granite shows relatively weak magnetic behaviour in AF-demagnetisation exper- iments, untypical for hematite. The alteration of the fresh granite also causes a change in magnetic fabric parameter, especially of the anisotropy factor. The magnetic min- eralogy from the altered granite in respect to the changes in rock magnetic properties will be discussed.

U-Pb zircon geochronology of intrusive and basement rocks in the Jacurici Valley region, Sao Francisco Craton, BA, Brazil; Geocronologia U-Pb em zircao de rochas intrusivas e de embasamento na regiao do Vale do Jacurici, Craton do Sao Francisco, BA

Energy Technology Data Exchange (ETDEWEB)

Silveira, Carlos Jose Sobrinho da; Frantz, Jose Carlos; Marques, Juliana Charao; Roos, Siegbert; Peixoto, Vinicius Medina, E-mail: silveira.carlosjose@hotmail.com, E-mail: jose.frantz@propesq.ufrgs.br, E-mail: juliana.marques@ufrgs.br, E-mail: sig_duda@yahoo.com.br, E-mail: vinimpeixoto@hotmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Laboratorio de Geologia Isotopica; Queiroz, Waldemir Jose Alves de, E-mail: waldemirqueiroz@hotmail.com [Companhia de Ferro Ligas da Bahia (FERBASA), Pojuca, BA (Brazil)

2015-09-15

The Jacurici Complex, located in the NE of the Sao Francisco Craton, is constituted by several Cr-mineralized mafic-ultramafic N-S bodies, possible fragments of a single sill disrupted during deformation. Some works suggest it is intruded on the Serrinha Block while others consider it in the Salvador-Curaca Belt. The basement on this region is informally divided into paragneisses and orthogneisses; the latter is supposed to be younger considering it is less deformed. Petrography revealed that some of the paragneisses are alkali-feldspar granite strongly milonitized. The orthogneisses occur at the north and consist, at least in part, of monzogranites with heterogeneous deformation, locally of low temperature. U-Pb zircon dating were performed for five representative samples. Just three provided good concordia ages. A mafic rock produced a 2102 ± 5 Ma age and it is petrographically similar to the metanorites described in the Jacurici Complex, being interpreted as the record of the first pulses of the mafic magmatism. A monzogranite yielded a 2995 ± 15 Ma age, older than expected, related to the Serrinha Block. The alkali-feldspar granite yielded a 2081 ± 3 Ma age. The Itiuba Syenite and the pegmatites that crosscut the Jacurici Complex have similar ages. Considering the lack of information about the supracrustal sequence that hosts the intrusive alkaline and mafic-ultramafic rocks at the Ipueira and the Medrado areas, it is possible that part of the terrain belongs to the Salvador-Curaca Belt. We suggest that the Jacurici Complex could be intruded after the tectonic amalgamation between the Serrinha Block and the older part of the Salvador-Curaca Belt and, therefore, could be hosted by both terrains. (author)

Application of kinematic vorticity and gold mineralization for the wall rock alterations of shear zone at Dungash gold mining, Central Eastern Desert, Egypt

Science.gov (United States)

Kassem, Osama M. K.; Abd El Rahim, Said H.; El Nashar, EL Said R.; AL Kahtany, Kaled M.

2016-11-01

The use of porphyroclasts rotating in a flowing matrix to estimate mean kinematic vorticity number (Wm) is important for quantifying the relative contributions of pure and simple shear in wall rocks alterations of shear zone at Dungash gold mine. Furthermore, it shows the relationship between the gold mineralization and deformation and also detects the orientation of rigid objects during progressive deformation. The Dungash gold mine area is situated in an EW-trending quartz vein along a shear zone in metavolcanic and metasedimentary host rocks in the Eastern Desert of Egypt. These rocks are associated with the major geologic structures which are attributed to various deformational stages of the Neoproterozoic basement rocks. We conclude that finite strain in the deformed rocks is of the same order of magnitude for all units of metavolcano-sedimentary rocks. The kinematic vorticity number for the metavolcanic and metasedimentary samples in the Dungash area range from 0.80 to 0.92, and together with the strain data suggest deviations from simple shear. It is concluded that nappe stacking occurred early during the underthrusting event probably by brittle imbrication and that ductile strain was superimposed on the nappe structure during thrusting. Furthermore, we conclude that disseminated mineralization, chloritization, carbonatization and silicification of the wall rocks are associated with fluids migrating along shearing, fracturing and foliation of the metamorphosed wall rocks.

lithologic characterisation of the basement aquifers of awe and ...

African Journals Online (AJOL)

Global Journal

resistivity exceeded 3000 ohm-m, then the bedrock is fresh and prospect for water is low (Olayinka and. Olorunfemi, 1992; Olorunfemi and Olorunniwo, 1990). Groundwater zones are found in the weathered and fractured zones in basement areas. In Ibarapa area of SW, Nigeria the associated fractured bedrock aquifers.

The Subduction of an Exhumed and Serpentinized Magma-Poor Basement Beneath the Northern Lesser Antilles Reveals the Early Tectonic Fabric at Slow-Spreading Mid-Oceanic Ridges

Science.gov (United States)

Marcaillou, B.; Klingelhoefer, F.; Laurencin, M.; Biari, Y.; Graindorge, D.; Jean-Frederic, L.; Laigle, M.; Lallemand, S.

2017-12-01

Multichannel and wide-angle seismic data as well as heat-flow measurements (ANTITHESIS cruise, 2016) reveal a 200x200km patch of magma-poor oceanic basement in the trench and beneath the outer fore-arc offshore of Antigua to Saint Martin in the Northern Lesser Antilles. These data highlight an oceanic basement with the following features: 1/ Absence of any reflection at typical Moho depth and layer2/layer3 limit depths. 2/ High Velocity Vp at the top (>5.5 km/s), low velocity gradient with depth (serpentinized at the slow-spreading mid-Atlantic Ridge 80 Myr ago, is currently subducting beneath the Northern Lesser Antilles. During the exhumation, early extension triggers penetrative shear zones sub-parallel to the ridge and to the transform fault. Eventually, this early extension generates sliding along the so-called detachment fault, while the other proto-detachment abort. Approaching the trench, the plate bending reactivates these weak zones in normal faults and fluid pathways promoting deep serpentinisation and localizing tectonic deformation at the plate interface. These subducting fluid-rich mechanically weak mantle rocks rise questions about their relation to the faster slab deepening, the lower seismic activity and the pervasive tectonic partitioning in this margin segment.

U-Pb and Sm-Nd preliminary geochronologic data on the Yaounde series, Cameroon: re-interpretation of the granulitic rocks as the suture of a collision in the ''Centrafrican'' belt

International Nuclear Information System (INIS)

Schmus, W.R. Van; Penaye, J.; Toteu, S.F.; Nzenti, J.P.

1993-01-01

U-Pb on zircons and Sm-Nd on whole-rock analyses have been applied on the schists, micaschists and granulitic gneisses of the Yaounde series. The results fix the granulitic metamorphism in the Yaounde series at 620±10 Ma and the deposition of the series during the Upper Proterozoic. In addition, another remnant of Lower Proterozoic basement, previously recognized in northern Cameroon, has been identified at Kekem northwest of the Yaounde series. The Yaounde granulitic unit is re-interpreted as the suture of a Pan-African collision between a passive margin (Archean Congo craton and its Birrimian Nyong cover) to the south and an intensive granitized active margin (dismembered eburnian basement and Upper Proterozoic series) to the north. (author). 14 refs., 4 figs

Stress rotation along pre-Cenozoic basement structures

Science.gov (United States)

Reiter, K.; Heidbach, O.; Henk, A.

2017-12-01

The in-situ stress state of the Earth's crust is under investigation since decades for both, scientific and economic purposes. Several methods have been established to indicate the contemporary orientation of the maximum compressive horizontal stress (SHmax). It is assumed that the same forces that drive plate motion are the first order stress sources and one could presume that SHmax is always parallel to plate motion, which is the case for some regions. However, deviations from this general trend occur in many regions. Therefore, second and third order sources of stress have been identified that potentially cause regional and local stress rotation with respect to the long wave-length trend imposed by plate tectonic forces. One group of such subordinate stress sources are lateral heterogeneities based on structures, petrothermal or petrophysical properties. The World Stress Map (WSM) project compiles systematically data records of the present day SHmax orientation. The increasing amount of stress orientation data allows to investigate areas with consistent stress rotation, divergent to the regional stress pattern. In our work we analyse the stress pattern variability and its causes beneath Germany. In the Molasse Basin in the Alpine foreland the SHmax orientation is perpendicular to the Alpine front as a consequence of gravitational potential energy of the orogen. SHmax is oriented in N-S direction in the central Alpine foreland and within the North German Basin. Between both, within the Mid-German Crystalline High, SHmax is divergent oriented in SE-NW direction. Neither gravitational potential energy nor petrothermal effects can be indicated as stress source. But when comparing the stress pattern with the Variscan basement structures it is obvious that SHmax is perpendicular oriented to this Palaeozoic basement structures. Therefore, petrophysical heterogeneities can be expected as reason for the observed stress rotation. Two assumptions can be made for the Mid

Regeneration of the epidermis and basement membrane of the planarian Dugesia japonica after total-body x irradiation

Energy Technology Data Exchange (ETDEWEB)

Hori, I.

1979-03-01

Fresh-water planarians were studied to examine effects of x rays on regeneration of the epidermis and basement membrane. During early stages of regeneration, free rhabdite-forming cells were associated with the wound epidermis and recruited it. In later stages, however, a gradual degeneration occurred in the epidermis and cells undergoing epithelization decreased in number. Eventually epidermal cells on the wound surface appeared necrotic as evidenced by pyknotic nuclei and vacuolized dense cytoplasm. The entire basement membrane could not be reconstituted in any stage after wounding though its precursor-like material was secreted in the interspace between epidermis and parenchyma. Morphological changes in extracellular products and in the cells surrounding the products suggest that epidermal cells which have covered the wound surface synthesize precursors of the basement membrane. Possible factors of a characteristic perturbation in epithelization and basement membrane formation after total-body irradiation are discussed.

Regeneration of the epidermis and basement membrane of the planarian Dugesia japonica after total-body x irradiation

International Nuclear Information System (INIS)

Hori, I.

1979-01-01

Fresh-water planarians were studied to examine effects of x rays on regeneration of the epidermis and basement membrane. During early stages of regeneration, free rhabdite-forming cells were associated with the wound epidermis and recruited it. In later stages, however, a gradual degeneration occurred in the epidermis and cells undergoing epithelization decreased in number. Eventually epidermal cells on the wound surface appeared necrotic as evidenced by pyknotic nuclei and vacuolized dense cytoplasm. The entire basement membrane could not be reconstituted in any stage after wounding though its precursor-like material was secreted in the interspace between epidermis and parenchyma. Morphological changes in extracellular products and in the cells surrounding the products suggest that epidermal cells which have covered the wound surface synthesize precursors of the basement membrane. Possible factors of a characteristic perturbation in epithelization and basement membrane formation after total-body irradiation are discussed

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)

Trace elements geochemistry of fractured basement aquifer in southern Malawi: A case of Blantyre rural

Science.gov (United States)

Mapoma, Harold Wilson Tumwitike; Xie, Xianjun; Nyirenda, Mathews Tananga; Zhang, Liping; Kaonga, Chikumbusko Chiziwa; Mbewe, Rex

2017-07-01

In this study, twenty one (21) trace elements in the basement complex groundwater of Blantyre district, Malawi were analyzed. The majority of the analyzed trace elements in the water were within the standards set by World Health Organization (WHO) and Malawi Standards Board (MSB). But, iron (Fe) (BH16 and 21), manganese (Mn) (BH01) and selenium (Se) (BH02, 13, 18, 19 and 20) were higher than the WHO and MSB standards. Factor analysis (FA) revealed up to five significant factors which accounted for 87.4% of the variance. Factor 1, 2 and 3 suggest evaporite dissolution and silicate weathering processes while the fourth factor may explain carbonate dissolution and pH influence on trace element geochemistry of the studied groundwater samples. According to PHREEQC computed saturation indices, dissolution, precipitation and rock-water-interaction control the levels of trace elements in this aquifer. Elevated concentrations of Fe, Mn and Se in certain boreholes are due to the geology of the aquifer and probable redox status of groundwater. From PHREEQC speciation results, variations in trace element species were observed. Based on this study, boreholes need constant monitoring and assessment for human consumption to avoid health related issues.

Asymmetric Effects of Subaerial and Subaqueous Basement Slopes on Self-Similar Morphology of Prograding Deltas

Science.gov (United States)

Lai, Steven Yueh Jen; Hsiao, Yung-Tai; Wu, Fu-Chun

2017-12-01

Deltas form over basements of various slope configurations. While the morphodynamics of prograding deltas over single-slope basements have been studied previously, our understanding of delta progradation over segmented basements is still limited. Here we use experimental and analytical approaches to investigate the deltaic morphologies developing over two-slope basements with unequal subaerial and subaqueous slopes. For each case considered, the scaled profiles of the evolving delta collapse to a single profile for constant water and sediment influxes, allowing us to use the analytical self-similar profiles to investigate the individual effects of subaerial/subaqueous slopes. Individually varying the subaerial/subaqueous slopes exerts asymmetric effects on the morphologies. Increasing the subaerial slope advances the entire delta; increasing the subaqueous slope advances the upstream boundary of the topset yet causes the downstream boundary to retreat. The delta front exhibits a first-retreat-then-advance migrating trend with increasing subaqueous slope. A decrease in subaerial topset length is always accompanied by an increase in subaqueous volume fraction, no matter which segment is steepened. Applications are presented for estimating shoreline retreat caused by steepening of basement slopes, and estimating subaqueous volume and delta front using the observed topset length. The results may have implications for real-world delta systems subjected to upstream tectonic uplift and/or downstream subsidence. Both scenarios would exhibit reduced topset lengths, which are indicative of the accompanied increases in subaqueous volume and signal tectonic uplift and/or subsidence that are at play. We highlight herein the importance of geometric controls on partitioning of sediment between subaerial and subaqueous delta components.

Uranium deposits in the metamorphic basement of the Rouergue massif. Genesis and extension of related albitization processes

International Nuclear Information System (INIS)

Schmitt, J.M.

1982-02-01

Albitization processes in the Rouergue metamorphic basement, probably Permian aged is evidenced. Late development of uranium orebodies occured within albitized zones. The detection of the latter serves as a highly valuable indirect guide for prospecting this type of deposits in a metamorphic basement [fr

KUALITAS UDARA DALAM RUANG DI DAERAH PARKIR BASEMENT DAN PARKIR UPPERGROUND (STUDI KASUS DI SUPERMARKET SEMARANG

Directory of Open Access Journals (Sweden)

Haryono S Huboyo

2016-03-01

Full Text Available Ever increasing building growth in urban areas is limited by land availability. Lack of space in this area lead to build high rise building rather landed building. In this type of building, parking area is built in the basement and or upperground inside the building. Within this enclosed space, indoor air quality might a problem. This study focus to compare emerged pollutants between basement parking area and upperground parking area in supermarket building. The dust sampler, the impinger and the CO monitor were used to measure TSP, NO2 and CO concentrations respectively in these areas during supermarket operations. In the basement area, in particular, the TSP concentrations tend to exceeds 300 µg/m3 mainly at weekend period. While for NO2 and CO concentrations still meet the air quality standard. Based on these findings it seems the main source of pollutants was derived from dust resuspension. Thus, the mitigation measures to reduce this dust resuspension should be emphasized in order to prevent air quality deterioration in the basement parking area.

Geoelectrical structure by electrical logs and Schlumberger sounding at the Akinomiya geothermal field, Akita Prefecture; Denki kenso oyobi Schlumberger ho ni yoru Akinomiya chinetsu chiiki no hiteiko kozo

Energy Technology Data Exchange (ETDEWEB)

Kajiwara, T; Takemoto, S

1997-05-27

Based on the electrical logging data of the existed well and Schlumberger sounding data obtained in 1974, a two-dimensional inversion analysis of the specific resistance profile was conducted at the Akinomiya geothermal field, Akita Prefecture. From the electrical logging data, relationships between the geology and the specific resistance were illustrated. The specific resistance values of basement rocks showed more than 100 ohm-m, which were higher than those of the other seams. Intrusive rocks and tuffs in the basement rocks showed locally low values less than 100 ohm-m. Younger volcanic rocks showed low values around 10 ohm-m. As a result of the two-dimensional inversion analysis, the basement rocks could be detected as high specific resistance layers. Accordingly, it was considered that the basement rocks in this field can be detected as high specific resistance layers by analyzing the results of field survey sufficiently. Low specific resistance zones were observed in the shallow depth, which corresponded to the fumarolic gases. There were some layers with remarkably varied specific resistance values, which were considered to be related with alteration. 6 refs., 3 figs.

Mercury isotope constraints on the source for sediment-hosted lead-zinc deposits in the Changdu area, southwestern China

Science.gov (United States)

Xu, Chunxia; Yin, Runsheng; Peng, Jiantang; Hurley, James P.; Lepak, Ryan F.; Gao, Jianfeng; Feng, Xinbin; Hu, Ruizhong; Bi, Xianwu

2018-03-01

The Lanuoma and Cuona sediment-hosted Pb-Zn deposits hosted by Upper Triassic limestone and sandstone, respectively, are located in the Changdu area, SW China. Mercury concentrations and Hg isotopic compositions from sulfide minerals and potential source rocks (e.g., the host sedimentary rocks and the metamorphic basement) were investigated to constrain metal sources and mineralization processes. In both deposits, sulfide minerals have higher mercury (Hg) concentrations (0.35 to 1185 ppm) than the metamorphic basement rocks (0.05 to 0.15 ppm) and sedimentary rocks (0.02 to 0.08 ppm). Large variations of mass-dependent fractionation (3.3‰ in δ202Hg) and mass-independent fractionation (0.3‰ in Δ199Hg) of Hg isotopes were observed. Sulfide minerals have Hg isotope signatures that are similar to the hydrothermal altered rocks around the deposit, and similar to the metamorphic basement, but different from barren sedimentary rocks. The variation of Δ199Hg suggests that Hg in sulfides was mainly derived from the underlying metamorphic basement. Mercury isotopes could be a geochemical tracer in understanding metal sources in hydrothermal ore deposits.

Nephritogenic antigen determinants in epidermal and renal basement membranes of kindreds with Alport-type familial nephritis.

Science.gov (United States)

Kashtan, C; Fish, A J; Kleppel, M; Yoshioka, K; Michael, A F

1986-10-01

We probed epidermal basement membranes (EBM) of acid-urea denatured skin from members of kindreds with Alport-type familial nephritis (FN) for the presence of antigens reactive with Goodpasture sera (GPS) and serum (FNS) from an Alport patient who developed anti-glomerular basement membrane (GBM) nephritis in a renal allograft. By immunoblotting, GPS reacted primarily with the 28,000 molecular weight (mol wt) monomer but also the 24,000 mol wt and 26,000 mol wt monomers of the noncollagenous globular domain (NC1) of type IV collagen from normal human GBM, while FNS identified only the 26,000-mol wt monomer. FNS reacted with EBM of 12 controls and nine unaffected male kindred members but not EBM of eight affected males. Five affected females exhibited interrupted reactivity of FNS with EBM. GPS showed variable reactivity with EBM and was not discriminating with respect to Alport-type FN. FNS did not stain renal basement members of five affected males. However, the EBM, tubular basement membrane, and Bowman's capsules of affected males contained antigens reactive with GPS. These immunochemical studies suggest that the FNS antigen is distinct from Goodpasture antigen(s). The expression of FNS antigen located on the NC1 domain of type IV collagen is altered in basement membranes of patients with Alport-type FN, and the distribution of this antigenic anomaly within kindreds suggests X-linked dominant transmission of a defective gene.

Human skin basement membrane-associated heparan sulphate proteoglycan: distinctive differences in ultrastructural localization as a function of developmental age

DEFF Research Database (Denmark)

Horiguchi, Y; Fine, J D; Couchman, J R

1991-01-01

was identical to that observed in neonatal and adult human skin. These findings demonstrate that active remodelling of the dermo-epidermal junction occurs during at least the first two trimesters, and affects not only basement membrane-associated structures but also specific antigens.......Recent studies have demonstrated that skin basement membrane components are expressed within the dermo-epidermal junction in an orderly sequence during human foetal development. We have investigated the ultrastructural localization of basement membrane-related antigens in human foetal skin...... at different developmental ages using two monoclonal antibodies to a well-characterized basement membrane-associated heparan sulphate proteoglycan. A series of foetal skin specimens (range, 54-142 gestational days) were examined using an immunoperoxidase immunoelectron microscopic technique. In specimens...

VEGF-A/Notch-Induced Podosomes Proteolyse Basement Membrane Collagen-IV during Retinal Sprouting Angiogenesis

Directory of Open Access Journals (Sweden)

Pirjo Spuul

2016-10-01

Full Text Available During angiogenic sprouting, endothelial tip cells emerge from existing vessels in a process that requires vascular basement membrane degradation. Here, we show that F-actin/cortactin/P-Src-based matrix-degrading microdomains called podosomes contribute to this step. In vitro, VEGF-A/Notch signaling regulates the formation of functional podosomes in endothelial cells. Using a retinal neovascularization model, we demonstrate that tip cells assemble podosomes during physiological angiogenesis in vivo. In the retina, podosomes are also part of an interconnected network that surrounds large microvessels and impinges on the underlying basement membrane. Consistently, collagen-IV is scarce in podosome areas. Moreover, Notch inhibition exacerbates podosome formation and collagen-IV loss. We propose that the localized proteolytic action of podosomes on basement membrane collagen-IV facilitates endothelial cell sprouting and anastomosis within the developing vasculature. The identification of podosomes as key components of the sprouting machinery provides another opportunity to target angiogenesis therapeutically.

Groundwater monitoring of an open-pit limestone quarry: groundwater characteristics, evolution and their connections to rock slopes.

Science.gov (United States)

Eang, Khy Eam; Igarashi, Toshifumi; Fujinaga, Ryota; Kondo, Megumi; Tabelin, Carlito Baltazar

2018-03-06

Groundwater flow and its geochemical evolution in mines are important not only in the study of contaminant migration but also in the effective planning of excavation. The effects of groundwater on the stability of rock slopes and other mine constructions especially in limestone quarries are crucial because calcite, the major mineral component of limestone, is moderately soluble in water. In this study, evolution of groundwater in a limestone quarry located in Chichibu city was monitored to understand the geochemical processes occurring within the rock strata of the quarry and changes in the chemistry of groundwater, which suggests zones of deformations that may affect the stability of rock slopes. There are three distinct geological formations in the quarry: limestone layer, interbedded layer of limestone and slaty greenstone, and slaty greenstone layer as basement rock. Although the hydrochemical facies of all groundwater samples were Ca-HCO 3 type water, changes in the geochemical properties of groundwater from the three geological formations were observed. In particular, significant changes in the chemical properties of several groundwater samples along the interbedded layer were observed, which could be attributed to the mixing of groundwater from the limestone and slaty greenstone layers. On the rainy day, the concentrations of Ca 2+ and HCO 3 - in the groundwater fluctuated notably, and the groundwater flowing along the interbedded layer was dominated by groundwater from the limestone layer. These suggest that groundwater along the interbedded layer may affect the stability of rock slopes.

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...

The crystalline basement of Estonia: rock complexes of the Palaeoproterozoic Orosirian and Statherian and Mesoproterozoic Calymmian periods, and regional correlations

Directory of Open Access Journals (Sweden)

Kirs, Juho

2009-12-01

Full Text Available New data on the Fennoscandian Shield and the Baltic area suggest a need for reinterpretation of the stratigraphy of Estonian Precambrian rock complexes. The rocks of the Tallinn Zone formed in the framework of the Fennian orogeny at the margin of the Bergslagen microcontinent 1.90–1.88 Ga ago. The precise age of the Alutaguse Zone is not known. It may have formed either during the 1.93–1.91 Ga Lapland–Savo orogeny or as a rifted eastern part of the Tallinn Zone in the Fennian orogeny. The granulites of western and southern Estonia belong to the volcanic arcs inside the 1.84–1.80 Ga Svecobaltic orogenic belt and show peak metamorphic conditions of 1.78 Ga. Small shoshonitic plutons formed 1.83–1.63 Ga, the small granitic plutons of the Wiborg Rapakivi Subprovince 1.67–1.62 Ga, and the Riga pluton 1.59–1.54 Ga ago.

Regional trends in radiogenic heat generation in the Precambrian basement of the Western Canadian Basin

Science.gov (United States)

Jones, F. W.; Majorowicz, J. A.

Radiogenic heat generation values for 381 basement samples from 229 sites in the western Canadian basin exhibit a lognormal frequency distribution. The mean value = 2.06 (S.D. = 1.22) µWm-3 is larger than the radiogenic heat generation values reported for the shield in the Superior (ca. 1.2 µWm-3, Jessop and Lewis, 1978) and Churchill (ca. 0.7 µWm-3, Drury, 1985) provinces. When equal Log A contour intervals are used to map the basement heat generation, three large zones of relatively high heat generation are found. One coincides with the Peace River Arch basement structure and one with the Athabasca axis (Darnley, 1981). There is no apparent indication of increased heat flow through the Paleozoic formations associated with these two zones. The third zone, in southwestern Saskatchewan, coincides with a high heat flow zone in the Swift Current area. The lack of correlation between heat flow and heat generation in Alberta may be due to the disturbance to the heat flow in the Paleozoic formations by water motion, or may indicate that the heat is from uranium, thorium and potassium isotope enrichment near the basement surface rather than enrichment throughout the entire upper crust.

[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.

Evidence for the existence of multiple heparan sulfate proteoglycans in the human glomerular basement membrane and mesangial matrix

NARCIS (Netherlands)

Groffen, Alexander J A; Hop, Frank W H; Tryggvason, Karl; Dijkman, Henri; Assmann, Karel J M; Veerkamp, Jacques H.; Monnens, Leo A H; Van Den Heuvel, Lambert P W J

1997-01-01

Heparan sulfate proteoglycans (HSPGs) are essential components of the glomerular basement membrane (GBM) carrying a strong anionic charge. A well- characterized extracellular HSPG is perlecan, ubiquitously expressed in basement membranes. A cDNA construct encoding domains I and II of human perlecan

Rac1 is essential for basement membrane-dependent epiblast survival

DEFF Research Database (Denmark)

He, Xiaowen; Liu, Jie; Qi, Yanmei

2010-01-01

During murine peri-implantation development, the egg cylinder forms from a solid cell mass by the apoptotic removal of inner cells that do not contact the basement membrane (BM) and the selective survival of the epiblast epithelium, which does. The signaling pathways that mediate this fundamental...

Fault rocks and veins formation in the crystalline Palaeozoic basement of the N margin of the Littoral Chain (Catalan Coastal Ranges, NE Spain)

Science.gov (United States)

Alías, Gemma; Belmonte, Alba; Cantarero, Irene; Inglés, Montserrat; Travé, Anna

2013-04-01

The Littoral Chain corresponds to a horst of NE-SW direction formed during the Neogene extension which in the studied area (Collserola-Montnegre massif) is mainly composed by Paleozoic materials. At the northern margin the horst limits with the Vallès basin which is infilled by Miocene detrital materials. In the Forques Hill, two km to the est of Martorell, an excellent outcrop of Ordovician phyllites summarise an spread tectonic evolution from Hercynian to Neogene deformation. This work evaluates the behaviour of phyllites during the Hercynian ductile deformation and later during the fragile Mesozoic and Neogene tectonics. The weakness of these rocks together with the situation very close to the Vallès Fault favour that this area concentrates many deformation structures related to extensional tectonics, such as veins, cataclasites and gouges. Phyllites present a pervasive regional hercynian foliation oriented WNW-ESE and dipping moderately to the NNE; a huge amount of quartz veins, up to 20% of the rock volume, were injected during and immediately after the main foliation development. Two groups of fractures cutting the phyllites can be distinguished in the field according to the fault rock products, the vein infilling, the orientation and the geometry. The first one corresponds to Mesozoic fractures that have a NE-SW trend and dip indistinctly to the NW or SE, in a conjugate system. They are characterized by the formation of a broad zone of 0,2 m up to 1,5 m formed either by cataclasites or en echelon veins that indicate a normal movement. The cataclasites are cohesive greenish rocks, with 50% of clasts of wall rock from mm to dm in size. Neoformed minerals in the matrix are chlorite - albite - barite ± titanite and rutile. Veins are white to pinkish in colour and two types of infill have been identified: albite - chlorite - iron oxides± rutile and dolomite - chlorite. The second group belongs to Neogene fractures which although similar orientation than those

Basement tectonics and flexural subsidence along western continental margin of India

Directory of Open Access Journals (Sweden)

D.K. Pandey

2017-09-01

Full Text Available The Paleocene-recent post-rift subsidence history recorded in the Mumbai Offshore Basin off western continental margin of India is examined. Results obtained through 2-D flexural backstripping modelling of new seismic data reveal considerable thermo-tectonic subsidence over last ca. 56 Myr. Reverse post-rift subsidence modelling with variable β stretching factor predicts residual topography of ca. 2000 m to the west of Shelf Margin Basin and fails to restore late Paleocene horizon and the underlying igneous basement to the sea level. This potentially implies that: (1 either the igneous basement formed during the late Cretaceous was emplaced under open marine environs; or (2 a laterally varying cumulative subsidence occurred within Mumbai Offshore Basin (MOB during ca. 68 to ca. 56 Ma. Pre-depositional topographic variations at ca. 56 Ma across the basin could be attributed to the extensional processes such as varied lower crustal underplating along Western Continental Margin of India (WCMI. Investigations about basement tectonics after unroofing of sediments since late Paleocene from this region support a transitional and heavily stretched nature of crust with high to very high β factors. Computations of past sediment accumulation rates show that the basin sedimentation peaked during late Miocene concurrently with uplift of Himalayan–Tibetan Plateau and intensification of Indian monsoon system. Results from basin subsidence modelling presented here may have significant implications for further studies attempting to explore tectono–climatic interactions in Asia.

Reconstruction of crustal blocks of California on the basis of initial strontium isotopic compositions of Mesozoic granitic rocks

Science.gov (United States)

Kistler, Ronald Wayne; Peterman, Zell E.

1978-01-01

Initial 87Sr/ 86 Sr was determined for samples of Mesozoic granitic rocks in the vicinity of the Garlock fault zone in California. These data along with similar data from the Sierra Nevada and along the San Andreas fault system permit a reconstruction of basement rocks offset by the Cenozoic lateral faulting along both the San Andreas and Garlock fault systems. The location of the line of initial 87Sr/ 86 Sr = 0.7060 can be related to the edge of the Precambrian continental crust in the western United States. Our model explains the present configuration of the edge of Precambrian continental crust as the result of two stages of rifting that occurred about 1,250 to 800 m.y. ago, during Belt sedimentation, and about 600 to 350 m.y. ago, prior to and during the development of the Cordilleran geosyncline and to left-lateral translation along a locus of disturbance identified in the central Mojave Desert. The variations in Rb, Sr, and initial 87Sr/ 86 Sr of the Mesozoic granitic rocks are interpreted as due to variations in composition and age of the source materials of the granitic rocks. The variations of Rb, Sr, and initial 87Sr/ 86 Sr in Mesozoic granitic rocks, the sedimentation history during the late Precambrian and Paleozoic, and the geographic position of loci of Mesozoic magmatism in the western United States are related to the development of the continental margin and different types of lithosphere during rifting.

Review of potential host rocks for radioactive waste disposal in the southeast United States: Southeastern Coastal Plain Subregion

International Nuclear Information System (INIS)

1980-10-01

A literature review was made of the geological characteristics of the Southeastern Coastal Plain physiograhic province in the states of Maryland, Virginia, North Carolina, South Carolina, and Georgia. The purpose of this study was to identify candidate exploration areas for the possible location of a mined repository for the storage of radioactive waste in the argillaceous sedimentary rocks of the Coastal Plain. Candidate areas were selected on the basis of geological characteristics, available subsurface data, and generally accepted requirements for waste isolation developed by previous studies. Factors considered in the evaluation include the stratigraphy and lithology, geologic history, structure, seismicity, hydrogeology, and natural resources of the candidate area. Unlike other potential regions, the Southeastern Coastal Plain is not composed of competent rock, but consists primarily of unconsolidated and water-saturated sediments overlying a basement of crystalline and metavolcanic rocks. Thus, construction of both shafts and tunnels to depths of approx. 1000 meters may encounter difficulties. Socio-economic and construction considerations have not been addressed in the evaluation. Based on the applied criteria, four areas were selected as being most favorable for future field investigation. These include one in Maryland, one in North Carolina, and two in Georgia

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 ...

Hot rock energy projects : Australian context

Energy Technology Data Exchange (ETDEWEB)

Goldstein, B.A.; Malavazos, M. [Society of Petroleum Engineers, Richardson, TX (United States); Hill, A.J.; Coda, J. [Primary Industries and Resources South Australia, Adelaide (Australia)]|[Australian Geothermal Energy Group, Adelaide (Australia); Budd, A.R.; Holgate, F.L. [Australian Geothermal Energy Group, Adelaide (Australia)]|[Geoscience Australia, Adelaide (Australia)

2008-10-15

The Australia Geothermal Energy Group is an alliance of companies, government agencies and research organizations with an interest in promoting geothermal energy use. Hot rocks (HR) geothermal energy is a valued addition to the portfolio of safe, secure and competitive energy supplies because it offers the potential of inexhaustible geothermal heat energy with zero emissions. Australia's vast HR resources have attracted global interest and government support for HR projects, which call upon integrated expertise from the petroleum minerals and power industries. Funding from the Australian government is aimed at reducing critical, sector-wide uncertainties and equates to nearly 25 per cent of the cost of the private sector's field efforts to date. A national HR resource assessment and a road-map for the commercialization of Australian HR plays will be published in 2008 to help in the decision making process by portfolio managers. The challenges and prospects for HR projects in Australia were presented. It has been estimated that converting only 1 per cent of Australia's crustal energy from depths of 5 km and 150 degrees C to electricity would supply 26,000 years of Australia's 2005 primary power use. The factors that distinguish Australian HR resources include abundant radioactive granites and areas of recent volcanic activity; and, Australia is converging with Indonesia on a plate scale resulting in common, naturally occurring subhorizontally fractured basement rocks that are susceptible to hydraulic fracture stimulation. Most projects are focused on HR to develop enhanced or engineered geothermal systems (EGS) to fuel binary power plants. Approximately 80 percent of these projects are located in South Australia. 14 refs., 3 tabs., 3 figs.

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.

Immunohistochemical localization of basement membrane components during hair follicle morphogenesis

DEFF Research Database (Denmark)

Westgate, G E; Shaw, D A; Harrap, G J

1984-01-01

Specific antisera were used to investigate the distributions of several basement membrane zone (BMZ) components, namely, bullous pemphigoid antigen (BPA), heparan sulfate proteoglycan (HSPG), laminin, and type IV collagen, during the development of hair follicles in late embryo rats. BPA was not ......Specific antisera were used to investigate the distributions of several basement membrane zone (BMZ) components, namely, bullous pemphigoid antigen (BPA), heparan sulfate proteoglycan (HSPG), laminin, and type IV collagen, during the development of hair follicles in late embryo rats. BPA...... of the elongating follicle. HSPG was associated with the basal cell layer prior to the appearance of hair follicle primordia and became BMZ-associated before birth but after follicle buds were first observed. HSPG was also found to be associated with the basal cell surfaces in the epidermis, but not in the hair...... follicle. Laminin and type IV collagen were continually present in epidermal and follicular BMZ both before and during development of hair follicles and were later present in the dermal papilla matrix. From these observations we conclude that (1) laminin and type IV collagen are functionally important...

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

Geophysical investigation of the Raton Basin

Science.gov (United States)

Cheney, R. S.

1982-05-01

This thesis correlates gravity, magnetic, and seismic data for the Raton Basin of Colorado and New Mexico. The gravity data suggest that the study area, and the region around it, is in isostatic equilibrium. The free air anomaly in the southern portion of the study area suggests lack of local compensation due to Quaternary volocanic rock. The volcanic rock thickness, calculated from the free air gravity data, is 180 m. The gravity data indicated a crustal thickness of about 45 km, and the crust thinned from west to east. A basement relief map was constructed from the Bouquer gravity data. Computer techniques were developed to calculate the depth to the basement surface and to plot a contour map of that surface. The Raton Basin magnetic map defined the same surface found on the basement relief map since the overlying sedimentary rocks have no magnetism; therefore, any magnetism present is caused by the basement rock. A seismic survey near capulin Mountain detected a high level of microseismicity that may be caused by adjustment along faults or dormant volcanic activity.

Water - rock interaction in different rock environments

International Nuclear Information System (INIS)

Lamminen, S.

1995-01-01

The study assesses the groundwater geochemistry and geological environment of 44 study sites for radioactive waste disposal. Initially, the study sites were divided by rock type into 5 groups: (1) acid - intermediate rocks, (2) mafic - ultramafic rocks, (3) gabbros, amphibolites and gneisses that contain calc-silicate (skarn) rocks, (4) carbonates and (5) sandstones. Separate assessments are made of acid - intermediate plutonic rocks and of a subgroup that comprises migmatites, granite and mica gneiss. These all belong to the group of acid - intermediate rocks. Within the mafic -ultramafic rock group, a subgroup that comprises mafic - ultramafic plutonic rocks, serpentinites, mafic - ultramafic volcanic rocks and volcanic - sedimentary schists is also evaluated separately. Bedrock groundwaters are classified by their concentration of total dissolved solids as fresh, brackish, saline, strongly saline and brine-class groundwaters. (75 refs., 24 figs., 3 tabs.)

Studies on the Neogene Tertiary strata distributed in the central part of Tottori prefecture

International Nuclear Information System (INIS)

Yoshitani, Akihiko; Yoshizawa, Junko.

1978-01-01

The Neogene Tertiary strata, distributed in the central part of Tottori Prefecture, are volcano-stratigraphically classified, as shown in Figure 3. The Miocene strata are divided into Ojika formation and Mitoku formation in ascending order. Ojika formation, composed of plagio-rhyolitic pyroclastics and lavas, abuts against the basement rocks. Furthermore, some breaccias derived from the talus basal conglomerate beds are found in Ojika formation. Mitoku formation abuts both against the basement rocks and Ojika formation, and sometimes overlaps on the basement rocks. From the investigation into the Miocene strata, it is clarified that the depression took place prior to the volcanic activities at the earliest stage of the present Miocene sedimentary basin. (author)

Calculations of the Temperature Evolution of a Repository for Spent Fuel in Crystalline and Sedimentary Rocks

International Nuclear Information System (INIS)

Sato, R.; Sasaki, T.; Ando, K.; Smith, P.A.; Schneider, J.W.

1998-08-01

Thermal evolution is a factor influencing repository design, and must be considered in safety assessment, since many of the processes that affect the long-term safety are temperature dependent. This report presents calculations of the thermal evolution of a repository for spent nuclear fuel. The calculations are based on a provisional repository near-field design in which spent fuel is encapsulated in composite copper-steel canisters, which are emplaced centrally along the horizontal axes of repository tunnels, with the space around the canisters backfilled with bentonite. The temperature of these near-field components varies with time, due to the radiogenic heat produced by the spent fuel. The rate of heat production per canister depends on the initial composition of the fuel, its reactor history, the period of intermediate storage before final disposal and the loading of the canisters. The rate decreases with time, as shorter-lived radionuclides decay. The base-case calculation considers spent fuel that is assumed to generate 1000 W per canister, 40 years after unloading of the fuel from the reactor. The results of the base case calculation indicate that the temperatures at the bentonite/host rock interface, at the centre of the bentonite and at the bentonite/canister interface rise to 98 o C, 103 o C and 126 o C, respectively, before declining towards the ambient temperature of the host rock which, in the base case, is taken to be the crystalline basement of Northern Switzerland. In addition to the base case, parameter variations are examined that investigate the sensitivity of thermal evolution to alternative heat output, design specifications and to uncertainties in material properties. Key findings include (i), that an increase in heat generation to 1500 W per canister 40 years after unloading results in a significant increase of repository temperatures (e.g. at the bentonite/host rock interface, an increase of 22 o C is observed), (ii), that a decrease in

The furnace in the basement: Part 1, The early days of the Hot Dry Rock Geothermal Energy Program, 1970--1973

Energy Technology Data Exchange (ETDEWEB)

Smith, M.C.

1995-09-01

This report presents the descriptions of the background information and formation of the Los Alamos Scientific Laboratory Geothermal Energy Group. It discusses the organizational, financial, political, public-relations,geologic, hydrologic, physical, and mechanical problems encountered by the group during the period 1970--1973. It reports the failures as well as the successes of this essential first stage in the development of hot dry rock geothermal energy systems.

Very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) investigation for groundwater potential evaluation in a complex geological terrain around the Ijebu-Ode transition zone, southwestern Nigeria

International Nuclear Information System (INIS)

Osinowo, Olawale O; Olayinka, A Idowu

2012-01-01

Groundwater exploration in either a basement or sedimentary environment is often fairly well defined and focuses on delineating weathered/fractured rocks or saturated formations, respectively. Conversely, unique geological structures, the complex coexistence of different rock types and poorly defined basal/lateral contacts between basement and sedimentary rocks make groundwater development in a geological transition environment very challenging. Ijebu-Ode and its environs lie within such a problematic transition zone, between the Precambrian basement rocks and Cretaceous sediments of the Dahomey Basin, in southwestern Nigeria, where associated acute groundwater development challenges require adequate subsurface information to maximize its groundwater resource potential. This study integrated very low frequency electromagnetic (VLF-EM) and electrical resistivity (ER) geophysical prospecting techniques for a detailed terrain study of Ijebu-Ode in order to establish the reasons for the low groundwater resource potential in the area. Thirty five VLF-EM profiles, 140 vertical electrical soundings (VES) and relevant hydrogeological data were acquired along grids and profiles. Data were filtered, inverted and enhanced using appropriate software packages. The current density and geoelectric parameters of the VLF-EM and VES data were employed to generate terrain maps, the conductivity distribution and a subsurface basement model of the study area. Current density plots and geoelectric parameters identified up to three layers in the basement complex terrain which comprised lateritic topsoil, weathered basement and fresh basement rocks. The five layers encountered in the sedimentary terrain were topsoil, a lateritic unit, a dry sandy unit, a saturated sandy unit and fresh basement rocks. The hydraulic conductivity of the thick (3–18 m) lateritic unit was determined to be 1.32 × 10 −5 mm s −1 , while that of the underlying sandy units ranged from 2.65 × 10 −4 to 1

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

Uranium distributions in the mineral constituents of granitoid rocks and the associated pegmatites at Wadi Abu Had, north eastern desert, Egypt

International Nuclear Information System (INIS)

Nossair, L.M.; Moharem, A.F.; Abdel Warith, A.

2007-01-01

Wadi Abu Had area is located at the northern part of the Eastern Desert of Egypt. It covers about 55 km2 of the crystalline basement rocks stretching between latitudes 28o 15'- 28o 25' N and longitudes 32o 25' - 32o 35' E. Abu Had younger granites are fertile (uraniferous) granites as they possess U-contents greater than 11 ppm. Their associated pegmatites show higher U-contents than those of granitoid rocks and hosting secondary uranium minerals. Numerous unzoned and zoned pegmatite pockets are associated with the marginal parts of granodiorite and within younger granites. Zoned pegmatites are the most radioactive ones. They are composed of extremely coarse-grained milky quartz core, intermediate zone of mica and wall zone of feldspars. An alteration zone with secondary uranium minerals (uranophane and beta-uranophane) is found at the contact between quartz core and the intermediate zone.

Oxygen isotope fine structure and fluid throughput of the Tongonan geothermal field, Philippines

International Nuclear Information System (INIS)

Scott, G.L.; Blattner, P.; Department of Scientific and Industrial Research, Lower Hutt

1986-01-01

Oxygen isotope ratios for 40 reservoir rocks from the plutonic basement and overlying andesitic rocks, and 14 separated geothermal quartz samples from the volcanics, range from 2.5 to 9.9 per mil. The lowest δ 18 O values (average 2.9 per mil) in diorite cores from wells 401, 407 and 410 are located in the most productive northwest (Mahiao) sector of the field. In the Malitbog sector, the average δ 18 O values for basement rocks are higher (c. 4.6 per mil). Plutonic rock samples from the Mamban (well MN1) sector, located outside the present-day field margin, are only slightly altered (6 per mil) except possibly near the contact zone between the basement and overlying volcanics. The highest cumulative fluid/rock ratios are calculated for the Mahiao sector, whereas Malitbog is possibly a relatively recent extension of the field. Relatively shallow (Bao Formation) quartz has δ 18 O values suggesting past tectonic uplift

The Effect of Mechanical Characteristics of Basal Decollement and Basement Structures on Deformation of the Zagros Basin

OpenAIRE

Bahroudi, Abbas

2003-01-01

Two fundamental structural elements, basement architecture and basal decollement, play a significant role in the evolution of a tectonically active region. Using different approaches (field data, literature review and analogue models) this thesis demonstrates that these two elements affected the deformation style in the Zagros fold-thrust belt during Mesozoic extensional and Cenozoic contractional episodes. Reassessment of available data suggests a new configuration for the basement to Zagro...

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

A geochemical study of the Precambrian basement granites from the Borggård borehole on Bornholm, Denmark, suggests that the granites were moderately weathered (Chemical Index of Alteration-CIA = 66-71) during subaerial exposure in a humid climate. The microcline is well preserved, whereas plagioclase was thoroughly altered to clay minerals (Plagioclase Index of Alteration-PIA = 93-99) which is likely due to its original Ca-rich composition. The primary Fe-Ti accessory minerals were oxidized to hematite and anatase. Evidence from REE distribution patterns and immobile element ratios, e.g. Zr/Hf and Nb/Ta, between the weathered basement granite from the Borggård borehole and regional granitoids on Bornholm, constrains the Svaneke Granite as the original basement lithology. A tau (τ) mass transport model (assuming immobile Ti) was applied to quantify the mass transfer during weathering of the basement granite. The results show a depletion of major elements in the following order: Na > Ca > Mg > Si; Al and Ti are immobile and stay constant; K shows sample dependent enrichment or depletion; Fe is slightly enriched. The Cambrian sandstone overlying the basement in the Borggård borehole, assigned to the Gadeby Member of the Nexø Formation, is feldspathic litharenite-litharenite in composition. Provenance indicators including (Gd/Yb)N, Zr/Hf and Nb/Ta ratios and petrological features indicate that source material was derived from both weathered and fresh basement granite of intermediate composition. The Gadeby Member equivalents in Germany, the basal lower Cambrian Adlergrund Konglomerat Member (AKM) in the offshore G-14 well north of Rügen, and the approximately coeval Lubmin Sandstein Formation (LSF) from the Loissin-1 borehole, mainland Germany, must have been sourced from a basement with compositions comparable to the intermediate group of the regional granitoids on Bornholm. The source materials for the AKM (CIA = 71-72, PIA = 94-96), the Gadeby Member in the

Nephritogenic antigen determinants in epidermal and renal basement membranes of kindreds with Alport-type familial nephritis.

OpenAIRE

Kashtan, C; Fish, A J; Kleppel, M; Yoshioka, K; Michael, A F

1986-01-01

We probed epidermal basement membranes (EBM) of acid-urea denatured skin from members of kindreds with Alport-type familial nephritis (FN) for the presence of antigens reactive with Goodpasture sera (GPS) and serum (FNS) from an Alport patient who developed anti-glomerular basement membrane (GBM) nephritis in a renal allograft. By immunoblotting, GPS reacted primarily with the 28,000 molecular weight (mol wt) monomer but also the 24,000 mol wt and 26,000 mol wt monomers of the noncollagenous ...

Strike-slip linked core complexes: A new kinematic model of basement rock exhumation in a crustal-scale fault system

Science.gov (United States)

Meyer, Sven Erik; Passchier, Cees; Abu-Alam, Tamer; Stüwe, Kurt

2014-05-01

Metamorphic core complexes usually develop as extensional features during continental crustal thinning, such as the Basin and Range and the Aegean Terrane. The Najd fault system in Saudi Arabia is a 2000 km-long and 400 km-wide complex network of crustal-scale strike-slip shear zones in a Neoproterozoic collision zone. Locally, the anastomosing shear zones lead to exhumation of lower crustal segments and represent a new kinematic model for the development of core complexes. We report on two such structures: the Qazaz complex in Saudi Arabia and the Hafafit complex in Egypt. The 15 km-wide Qazaz complex is a triangular dome of gently dipping mylonitic foliations within the 140 km-long sinistral strike-slip Qazaz mylonite zone. The gneissic dome consists of high-grade rocks, surrounded by low-grade metasediments and metavolcanics. The main SE-trending strike-slip Qazaz shear zone splits southwards into two branches around the gneiss dome: the western branch is continuous with the shallow dipping mylonites of the dome core, without overprinting, and changes by more than 90 degrees from a NS-trending strike-slip zone to an EW-trending 40 degree south-dipping detachment that bounds the gneiss dome to the south. The eastern SE-trending sinistral strike-slip shear zone branch is slightly younger and transects the central dome fabrics. The gneiss dome appears to have formed along a jog in the strike-slip shear zone during 40 km of horizontal strike-slip motion, which caused local exhumation of lower crustal rocks by 25 km along the detachment. The eastern shear zone branch formed later during exhumation, transacted the gneiss dome and offset the two parts by another 70 km. The Hafafit core complex in Egypt is of similar shape and size to the Qazaz structure, but forms the northern termination of a sinistral strike-slip zone that is at least 100 km in length. This zone may continue into Saudi Arabia as the Ajjaj shear zone for another 100 km. The NW trending strike slip

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.

Basement membrane changes in breast cancer detected by immunohistochemical staining for laminin

DEFF Research Database (Denmark)

Albrechtsen, R; Nielsen, M; Wewer, U

1981-01-01

The distribution of the basement membrane glycoprotein laminin was studied by the immunoperoxidase technique in benign and malignant human breast tissue and in axillary lymph nodes from patients with breast cancer. An antiserum prepared against rat laminin was used. The specificity...

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.)

Geology and uranium mineralization in the eastern part of the Kani Basin, Gifu, Central Japan

International Nuclear Information System (INIS)

Kobayashi, Takao

1989-01-01

The Misano and Utozaka uranium deposits in the eastern part of the Kani Basin are within Miocene nonmarine sediments which unconformably overlie Paleozoic-Mesozoic sediments and Cretaceous-Paleogene granites. These deposits are classified as sandstone type deposits structurally controlled by palaeo-channel structures formed on the pre-Miocene basement rocks. The host rock is the Kani lignite-bearing formation which is the lowermost sequence of the Kani Group. The age of the formation was estimated to be 20-19 Ma by fission track dating. The mineralized host sediments consist of conglomerates, arkosic, tuffaceous and carbonaceous sandstones. Although no primary uranium mineral was identified to date, it is considered that uranium is present in uranous form. The mineralization was strongly controlled by a fault structure within the basement granites as well as the channel structure formed on the basement rocks, especially on the granites. The enriched ore zone of the Misano deposit distributes within the basal part of the Kani lignite-bearing formation above the basement fault structure and in the palaeo-channel downward from the fault structure. The basement granites were also mineralized along the fault structure. Groundwater leached uranium form the basement granites, and migrated along the fault structure to the host sediments to form the deposite. (Kako, I.)

Temporal variations of Sr isotopic compositions for the rocks from Dogo, Oki islands Shimane Prefecture

International Nuclear Information System (INIS)

Fujimaki, Hirokazu; Xu Hong; Aoki, Ken-ichiro

1991-01-01

Fifty-three volcanic rocks from Dogo island, Oki, Shimane Prefecture, southwestern Japan were analyzed for Sr isotopic compositions with two basement rocks. The rock samples consist of calc-alkali rock suite, Nagaoda shoshonite-banakite suite, Oki trachyte-rhyolite suite, Dogo mugearite suite, Hei trachyte and Tsuzurao rhyolite series, and Daimanjiyama, Ohmine, Kuroshima, Shiroshimazaki, Saigo, and Misaki alkali basalt groups in the order of probable eruption sequence. The volcanic rocks of calc-alkali suite and shoshonite-banakite suite were produced before Japan Sea opening (ca. 15 Ma), and both have 87 Sr/ 86 Sr ratios higher than 0.7068. Long after Japan Sea opening Oki-trachyte-rhyolite suite was erupted (ca. 6.6 Ma); they have rather low 87 Sr/ 86 Sr ratios (0.7066-0.7081). Mugearites followed and have similar Sr isotopic composition, whereas 4.6 Ma old Daimanjiyama basalts have clearly low 87 Sr/ 86 Sr ratios (0.7050-0.7051). The rocks erupted 3-4 Ma seem to have the lowest 87 Sr/ 86 Sr ratios; they are Ohmine, Kuroshima, Shiroshimazaki alkali basalt suites (0.7044-0.7048). The 87 Sr/ 86 Sr ratios of the Saigo basalts erupted 0.84 Ma are higher than those erupted 3-4 Ma. The latest volcanic products in Dogo island, Misaki basalt suite has even higher 87 Sr/ 86 Sr ratios (0.7054-0.7057) than the Saigo basalt suite. Thus, temporal and systematic variation of Sr isotopic compositions of the volcanic rocks from Dogo can be recognized. The 87 Sr/ 86 Sr ratios of the rocks were once as high as 0.7066 or even higher than 0.708, but they started decreasing down to ca. 0.7044-0.7048 4-3 Ma ago. Since then the ratios rebounded to 0.7049-0.7055. The Hei trachyte and Tsuzurao rhyolite series are not included in this temporal and systematic change. The mantle diapir associated with Japan Sea spreading might have caused the decrease in the ratios, and either Pacific Ocean plate or Philippine Sea plate subduction may be responsible for this rebound. (author)

Identification of Zones and Areal Extent of Weathered Crystalline Basement in the Archean-Lower Proterozoic Crust of the South Tatar Arch

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N.B. Amelchenko

2017-08-01

Full Text Available Based on the data of geophysical surveys and deep drilling the depth to the crystalline basement and its weathered upper layer at the eastern flank of the South Tartar Arch varies from 1650 to 2500 m. Against the ongoing depletion of hydrocarbon reserves in the Paleozoic reservoirs of the region the basement becomes a promising exploration target. However the study of its architecture, composition and areal extent is largely hindered by so far very limited coring in this interval. In previous research correlation of core data and wireline logs was used for petrophysical characterization and identification of zones in a vertical profile of the upper weathered layer of the basement in the deep parametric test wells 50 Novournyak and 2000 Tyimazy with most complete core recovery. These characterization criteria have been utilized for analysis of 750 deep wells drilled in Bashkortostan within the South Tatar Arch which is bounded in the south by the Serafimovsko-Baltaevskiy Graben. In 340 wells based on wireline and production logs the upper weathered layer of the basement revealed certain distinct features of vertical zonation. The analysis resulted in thickness maps for Zone B and combined thickness maps for Zones B + C where the weathered basement is characterized by two morphological types – linear-areal and linear-fractured. The findings support the initial assumption that the obtained petrophysical characteristics may be applied to identify the weathered crystalline basement in wells with no core.

Thermal Inertia of Rocks and Rock Populations

Science.gov (United States)

Golombek, M. P.; Jakosky, B. M.; Mellon, M. T.

2001-01-01

The effective thermal inertia of rock populations on Mars and Earth is derived from a model of effective inertia versus rock diameter. Results allow a parameterization of the effective rock inertia versus rock abundance and bulk and fine component inertia. Additional information is contained in the original extended abstract.

Metasomatic tourmalinite formation along basement-cover decollements, Orobic Alps, Italy

Science.gov (United States)

Slack, J.F.; Passchier, C.W.; Zhang, J.S.

1996-01-01

Cryptocrystalline tourmalinites that occur discontinuously for ???30 km along basement-cover de??collements of the Orohic Alps (Italy) formed by the metasomatism of aluminous cataclasites derived from Permian conglomerates and/or feldspathic sandstones. Using Al as an immobile element monitor, calculations show that the majority of tourmalinites in the region formed through the addition of moderate to significant amounts of B, Mg, Na, Sr, and Be, and the loss of moderate to significant Mn, Ca, K, P, Rb, Ba, and Cr; minor Si, Ti, V, light REE, and Eu also were lost. Data tor relatively immobile Al, Zr, Th, Sc, Nb, and heavy REE indicate that, on average, these tourmalinites formed through ???12% net mass loss assuming an original conglomerate protolith, or through ???7% net mass loss assuming a sandstone protolith. The B and other introduced constituents in the tourmalinites were deposited by hydrothermal fluids focused along and near basement-cover de??collements. These fluids, believed to be associated with late Hercynian felsic magmatism, probably are related to fluids that formed the tourmaline-rich U-Mo-Zn deposits at the nearby Novazza mine and the U-Zn deposits at the nearby Val Vedello mine.

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

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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

The basement membrane constituents in the mouse embryo's tooth. An autoradiographic study

International Nuclear Information System (INIS)

Osman, M.

1987-01-01

Enamel organs isolated from the lower first teeth of 18-days old white mouse embryo by trypsin treatment were used in this study. The organs were cultured during periods of increasing time on a semi-solid medium containing cock serum. In another chase experiments, the organs were cultured on a liquid medium containing proline- 3 H, leucine- 3 H, and glucosamine- 3 H, were studied by autoradiography using both light and electron microscopes. It has been shown that the nature of the culture medium does not apparently interfere with the ability of the enamel to reconstitute the basement membrane. On the other hand, it have been found obvious differences concerning the kinetic of the used isotopes. The results indicate that the turn-over of the basement membrane constituents represents a continuous and homogenous process which continues to take place during, before and after reconstitution. 42 refs. (author)

Time variation of 222Rn concentration and gamma level in a half-basement room

International Nuclear Information System (INIS)

Iimoto, Takeshi; Eguchi, Hoshio; Kosako, Toshiso; Sugiura, Nobuyuki

1998-01-01

Correlation between 222 Rn (radon) concentration and gamma level in a half-basement has been discussed. In order to decrease the background count of a whole-body counter (WBC), a ventilation blower of 72 m 2 h -1 was installed. The device succeeded in a big reduction of radon concentration in the half-basement and then the background of WBC (NaI(Tl)) decreased to the 76.5% of the saturated value. Through a radon saturation test the exhalation rate of radon from concrete wall was estimated as 2.1 Bqm -2 h -1 by a simple model calculation. In addition, through a ventilation test, the procedure was analyzed by another simple model. (author)

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.

A three-dimensional geophysical model of the crust in the Barents Sea region: Model construction and basement characterization

Science.gov (United States)

Ritzmann, O.; Maercklin, N.; Inge, Faleide J.; Bungum, H.; Mooney, W.D.; Detweiler, S.T.

2007-01-01

BARENTS50, a new 3-D geophysical model of the crust in the Barents Sea Region has been developed by the University of Oslo, NORSAR and the U.S. Geological Survey. The target region comprises northern Norway and Finland, parts of the Kola Peninsula and the East European lowlands. Novaya Zemlya, the Kara Sea and Franz-Josef Land terminate the region to the east, while the Norwegian-Greenland Sea marks the western boundary. In total, 680 1-D seismic velocity profiles were compiled, mostly by sampling 2-D seismic velocity transects, from seismic refraction profiles. Seismic reflection data in the western Barents Sea were further used for density modelling and subsequent density-to-velocity conversion. Velocities from these profiles were binned into two sedimentary and three crystalline crustal layers. The first step of the compilation comprised the layer-wise interpolation of the velocities and thicknesses. Within the different geological provinces of the study region, linear relationships between the thickness of the sedimentary rocks and the thickness of the remaining crystalline crust are observed. We therefore, used the separately compiled (area-wide) sediment thickness data to adjust the total crystalline crustal thickness according to the total sedimentary thickness where no constraints from 1-D velocity profiles existed. The BARENTS50 model is based on an equidistant hexagonal grid with a node spacing of 50 km. The P-wave velocity model was used for gravity modelling to obtain 3-D density structure. A better fit to the observed gravity was achieved using a grid search algorithm which focussed on the density contrast of the sediment-basement interface. An improvement compared to older geophysical models is the high resolution of 50 km. Velocity transects through the 3-D model illustrate geological features of the European Arctic. The possible petrology of the crystalline basement in western and eastern Barents Sea is discussed on the basis of the observed seismic

Influence of pre-existing basement faults on the structural evolution of the Zagros Simply Folded belt: 3D numerical modelling

Science.gov (United States)

Ruh, Jonas B.; Gerya, Taras

2015-04-01

The Simply Folded Belt of the Zagros orogen is characterized by elongated fold trains symptomatically defining the geomorphology along this mountain range. The Zagros orogen results from the collision of the Arabian and the Eurasian plates. The Simply Folded Belt is located southwest of the Zagros suture zone. An up to 2 km thick salt horizon below the sedimentary sequence enables mechanical and structural detachment from the underlying Arabian basement. Nevertheless, deformation within the basement influences the structural evolution of the Simply Folded Belt. It has been shown that thrusts in form of reactivated normal faults can trigger out-of-sequence deformation within the sedimentary stratigraphy. Furthermore, deeply rooted strike-slip faults, such as the Kazerun faults between the Fars zone in the southeast and the Dezful embayment and the Izeh zone, are largely dispersing into the overlying stratigraphy, strongly influencing the tectonic evolution and mechanical behaviour. The aim of this study is to reveal the influence of basement thrusts and strike-slip faults on the structural evolution of the Simply Folded Belt depending on the occurrence of intercrustal weak horizons (Hormuz salt) and the rheology and thermal structure of the basement. Therefore, we present high-resolution 3D thermo-mechnical models with pre-existing, inversively reactivated normal faults or strike-slip faults within the basement. Numerical models are based on finite difference, marker-in-cell technique with (power-law) visco-plastic rheology accounting for brittle deformation. Preliminary results show that deep tectonic structures present in the basement may have crucial effects on the morphology and evolution of a fold-and-thrust belt above a major detachment horizon.

Insights on fluid-rock interaction evolution during deformation from fracture network geochemistry at reservoir-scale

Science.gov (United States)

Beaudoin, Nicolas; Koehn, Daniel; Lacombe, Olivier; Bellahsen, Nicolas; Emmanuel, Laurent

2015-04-01

Fluid migration and fluid-rock interactions during deformation is a challenging problematic to picture. Numerous interplays, as between porosity-permeability creation and clogging, or evolution of the mechanical properties of rock, are key features when it comes to monitor reservoir evolution, or to better understand seismic cycle n the shallow crust. These phenomenoms are especially important in foreland basins, where various fluids can invade strata and efficiently react with limestones, altering their physical properties. Stable isotopes (O, C, Sr) measurements and fluid inclusion microthermometry of faults cement and veins cement lead to efficient reconstruction of the origin, temperature and migration pathways for fluids (i.e. fluid system) that precipitated during joints opening or faults activation. Such a toolbox can be used on a diffuse fracture network that testifies the local and/or regional deformation history experienced by the rock at reservoir-scale. This contribution underlines the advantages and limits of geochemical studies of diffuse fracture network at reservoir-scale by presenting results of fluid system reconstruction during deformation in folded structures from various thrust-belts, tectonic context and deformation history. We compare reconstructions of fluid-rock interaction evolution during post-deposition, post-burial growth of basement-involved folds in the Sevier-Laramide American Rocky Mountains foreland, a reconstruction of fluid-rock interaction evolution during syn-depostion shallow detachment folding in the Southern Pyrenean foreland, and a preliminary reconstruction of fluid-rock interactions in a post-deposition, post-burial development of a detachment fold in the Appenines. Beyond regional specification for the nature of fluids, a common behavior appears during deformation as in every fold, curvature-related joints (related either to folding or to foreland flexure) connected vertically the pre-existing stratified fluid system

The significance of strike-slip faulting in the basement of the Zagros fold and thrust belt

Energy Technology Data Exchange (ETDEWEB)

Hessami, K.; Koyi, H.A.; Talbot, C.J. [Uppsala University (Sweden). Institute of Earth Sciences

2000-01-01

Lateral offsets in the pattern of seismicity along the Zagros fold and thrust belt indicate that transverse faults segmenting the Arabian basement are active deep-seated strike-slip faults. The dominant NW-SE trending features of the belt have undergone repeated horizontal displacements along these transverse faults. These reactivated basement faults, which are inherited from the Pan-African construction phase, controlled both deposition of the Phanerozoic cover before Tertiary-Recent deformation of the Zagros and probably the entrapment of hydrocarbons on the NE margin of Arabia and in the Zagros area. We have used observations of faulting recognized on Landsat satellite images, in conjunction with the spatial distribution of earthquakes and their focal mechanism solutions, to infer a tectonic model for the Zagros basement. Deformation in the NW Zagros appears to be concentrated on basement thrusts and a few widely-spaced north-south trending strike-slip faults which separate major structural segments. In the SE Zagros, two main structural domains can be distinguished. A domain of NNW-trending right-lateral faults in the northern part of the SE Zagros implies that fault-bounded blocks are likely to have rotated anticlockwise about vertical axes relative to both Arabia and Central Iran. In contrast, the predominance of NNE-trending left-lateral faults in the southern part of the SE Zagros implies that fault-bounded blocks may have rotated clockwise about vertical axes. We propose a tectonic model in which crustal blocks bounded by strike-slip faults in a zone of simple shear rotate about vertical axes relative to both Arabia and Central Iran. The presence of domains of strike-slip and thrust faulting in the Zagros basement suggest that some of the convergence between Arabia and Central Iran is accommodated by rotation and possible lateral movement of crust along the belt by strike-slip faults, as well as by obvious crustal shortening and thickening along thrust

ER stress and basement membrane defects combine to cause glomerular and tubular renal disease resulting from Col4a1 mutations in mice

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Frances E. Jones

2016-02-01

Full Text Available Collagen IV is a major component of basement membranes, and mutations in COL4A1, which encodes collagen IV alpha chain 1, cause a multisystemic disease encompassing cerebrovascular, eye and kidney defects. However, COL4A1 renal disease remains poorly characterized and its pathomolecular mechanisms are unknown. We show that Col4a1 mutations in mice cause hypotension and renal disease, including proteinuria and defects in Bowman's capsule and the glomerular basement membrane, indicating a role for Col4a1 in glomerular filtration. Impaired sodium reabsorption in the loop of Henle and distal nephron despite elevated aldosterone levels indicates that tubular defects contribute to the hypotension, highlighting a novel role for the basement membrane in vascular homeostasis by modulation of the tubular response to aldosterone. Col4a1 mutations also cause diabetes insipidus, whereby the tubular defects lead to polyuria associated with medullary atrophy and a subsequent reduction in the ability to upregulate aquaporin 2 and concentrate urine. Moreover, haematuria, haemorrhage and vascular basement membrane defects confirm an important vascular component. Interestingly, although structural and compositional basement membrane defects occurred in the glomerulus and Bowman's capsule, no tubular basement membrane defects were detected. By contrast, medullary atrophy was associated with chronic ER stress, providing evidence for cell-type-dependent molecular mechanisms of Col4a1 mutations. These data show that both basement membrane defects and ER stress contribute to Col4a1 renal disease, which has important implications for the development of treatment strategies for collagenopathies.

Removal of the basement membrane enhances corneal wound healing.

Science.gov (United States)

Pal-Ghosh, Sonali; Pajoohesh-Ganji, Ahdeah; Tadvalkar, Gauri; Stepp, Mary Ann

2011-12-01

Recurrent corneal erosions are painful and put patients' vision at risk. Treatment typically begins with debridement of the area around the erosion site followed by more aggressive treatments. An in vivo mouse model has been developed that reproducibly induces recurrent epithelial erosions in wild-type mice spontaneously within two weeks after a single 1.5 mm corneal debridement wound created using a dulled-blade. This study was conducted to determine whether 1) inhibiting MMP9 function during healing after dulled-blade wounding impacts erosion development and 2) wounds made with a rotating-burr heal without erosions. Oral or topical inhibition of MMPs after dulled-blade wounding does not improve healing. Wounds made by rotating-burr heal with significantly fewer erosions than dulled-blade wounds. The localization of MMP9, β4 integrin and basement membrane proteins (LN332 and type VII collagen), immune cell influx, and reinnervation of the corneal nerves were compared after both wound types. Rotating-burr wounds remove the anterior basement membrane centrally but not at the periphery near the wound margin, induce more apoptosis of corneal stromal cells, and damage more stromal nerve fibers. Despite the fact that rotating-burr wounds do more damage to the cornea, fewer immune cells are recruited and significantly more wounds resolve completely. Copyright © 2011 Elsevier Ltd. All rights reserved.

Stratigraphy and eruption age of the volcanic rocks in the west of Miyanoharu area, Kumamoto Prefecture

International Nuclear Information System (INIS)

Kamata, Hiroki

1985-01-01

The detailed stratigraphic survey, K-Ar age determinations and NRM measurements of the volcanic rocks in the west of Miyanoharu area revealed the volcanic history as follows: Hornblende andesite lava with plagioclase megacryst (Yoshinomoto lava) erupted during 2.8 - 2.5 Ma (Gauss normal epoch), accompanied by small amount of pyroclastic materials. After this eruption, Kamitarumizu hypersthene-augite andesite lava (1.7 - 1.3 Ma; reversed), Yabakei pyroclastic flow (0.99 Ma; Jaramillo normal event), Yamakogawa biotite rhyolite lava (0.9 Ma; reversed) and Daikanbo hypersthene-augite andesite lava (0.8 Ma; normal) erupted successively prior to the Aso-1 pyroclastic flow (0.3 - 0.4 Ma). Both the K-Ar ages and NRM data are consistent with the stratigraphic sequence (Fig. 2), which suggests that the activity of andesite and rhyolite is intercalated with each other during Pleistocene in the studied area. The compiled radiometric age data in the central-north Kyushu show that the age of volcanic activity that has previously been inferred as middle Miocene is of Pliocene, and its distribution is limited within the quadrilateral (60 km x 40 km) where the pre-Tertiary basement rocks are absent. The distribution of volcanic rocks is historically zonated such that the rocks of older age up to 5 Ma develop toward the outer rim of the quadrilateral, which coincides with the 0 mgal contour bordering the large low Bouguer anomaly. These facts suggest that the volcanic activity is remarkably relevant to the subsidence of this area, where the volcano-tectonic depression has been formed after 5 Ma to the present, and filled with lavas and pyroclastic materials with scarce sedimentary rocks in the tension stress field during Plio-Pleistocene age. (Kubozono, M.)

The effect of offset on fracture permeability of rocks from the Southern Andes Volcanic Zone, Chile

Science.gov (United States)

Pérez-Flores, P.; Wang, G.; Mitchell, T. M.; Meredith, P. G.; Nara, Y.; Sarkar, V.; Cembrano, J.

2017-11-01

The Southern Andes Volcanic Zone (SVZ) represents one of the largest undeveloped geothermal provinces in the world. Development of the geothermal potential requires a detailed understanding of fluid transport properties of its main lithologies. The permeability of SVZ rocks is altered by the presence of fracture damage zones produced by the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). We have therefore measured the permeability of four representative lithologies from the volcanic basement in this area: crystalline tuff, andesitic dike, altered andesite and granodiorite. For comparative purposes, we have also measured the permeability of samples of Seljadalur basalt, an Icelandic rock with widely studied and reported hydraulic properties. Specifically, we present the results of a systematic study of the effect of fractures and fracture offsets on permeability as a function of increasing effective pressure. Baseline measurements on intact samples of SVZ rocks show that the granodiorite has a permeability (10-18 m2), two orders of magnitude higher than that of the volcanic rocks (10-20 m2). The presence of throughgoing mated macro-fractures increases permeability by between four and six orders of magnitude, with the highest permeability recorded for the crystalline tuff. Increasing fracture offset to produce unmated fractures results in large increases in permeability up to some characteristic value of offset, beyond which permeability changes only marginally. The increase in permeability with offset appears to depend on fracture roughness and aperture, and these are different for each lithology. Overall, fractured SVZ rocks with finite offsets record permeability values consistent with those commonly found in geothermal reservoirs (>10-16 m2), which potentially allow convective/advective flow to develop. Hence, our results demonstrate that the fracture damage zones developed within the SVZ produce permeable regions, especially within the

Metamorphism of the northern Liaoning Complex: Implications for the tectonic evolution of Neoarchean basement of the Eastern Block, North China Craton

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Kam Kuen Wu

2013-05-01

Full Text Available As one of the areas where typical late Archean crust is exposed in the Eastern Block of the North China Craton, the northern Laioning Complex consists principally of tonalitic-trondhjemitic-granodioritic (TTG gneisses, massive granitoids and supracrustal rocks. The supracrustal rocks, named the Qingyuan Group, consist of interbedded amphibolite, hornblende granulite, biotite granulite and BIF. Petrological evidence indicates that the amphibolites experienced the early prograde (M1, peak (M2 and post-peak (M3 metamorphism. The early prograde assemblage (M1 is preserved as mineral inclusions, represented by actinotite + hornblende + plagioclase + epidote + quartz + sphene, within garnet porphyroblasts. The peak assemblage (M2 is indicated by garnet + clinopyroxene + hornblende + plagioclase + quartz + ilmenite, which occur as major mineral phases in the rock. The post-peak assemblage (M3 is characterized by the garnet + quartz symplectite. The P–T pseudosections in the NCFMASHTO system constructed by using THERMOCALC define the P–T conditions of M1, M2 and M3 at 490–550 °C/<4.5 kbar, 780–810 °C/7.65–8.40 kbar and 630–670 °C/8.15–9.40 kbar, respectively. As a result, an anticlockwise P–T path involving isobaric cooling is inferred for the metamorphic evolution of the amphibolites. Such a P–T path suggests that the late Archean metamorphism of the northern Liaoning Complex was related to the intrusion and underplating of mantle-derived magmas. The underplating of voluminous mantle-derived magmas leading to metamorphism with an anticlockwise P–T path involving isobaric cooling may have occurred in continental magmatic arc regions, above hot spots driven by mantle plumes, or in continental rift environments. A mantle plume model is favored because this model can reasonably interpret many other geological features of late Archean basement rocks from the northern Liaoning Complex in the Eastern Block of

Coexistence of anti-glomerular basement membrane antibodies and myeloperoxidase-ANCAs in crescentic glomerulonephritis

NARCIS (Netherlands)

Rutgers, Abraham; Slot, Marjan; van Paassen, Pieter; van Breda Vriesman, Peter; Heeringa, Peter; Tervaert, Jan Willem Cohen

BACKGROUND: In a substantial proportion of patients with crescentic glomerulonephritis (CGN), both anti-glomerular basement membrane (GBM) antibodies and antineutrophil cytoplasmic antibodies (ANCAs) with specificity for myeloperoxidase (MPO-ANCA) are detected. In the present study, we questioned

Implications of Eocene-age Philippine Sea and forearc basalts for initiation and early history of the Izu-Bonin-Mariana arc

Science.gov (United States)

Yogodzinski, Gene M.; Bizimis, Michael; Hickey-Vargas, Rosemary; McCarthy, Anders; Hocking, Benjamin D.; Savov, Ivan P.; Ishizuka, Osamu; Arculus, Richard

2018-05-01

Whole-rock isotope ratio (Hf, Nd, Pb, Sr) and trace element data for basement rocks at ocean drilling Sites U1438, 1201 and 447 immediately west of the KPR (Kyushu-Palau Ridge) are compared to those of FAB (forearc basalts) previously interpreted to be the initial products of IBM subduction volcanism. West-of-KPR basement basalts (drill sites U1438, 1201, 447) and FAB occupy the same Hf-Nd and Pb-Pb isotopic space and share distinctive source characteristics with εHf mostly > 16.5 and up to εHf = 19.8, which is more radiogenic than most Indian mid-ocean ridge basalts (MORB). Lead isotopic ratios are depleted, with 206Pb/204Pb = 17.8-18.8 accompanying relatively high 208Pb/204Pb, indicating an Indian-MORB source unlike that of West Philippine Basin plume basalts. Some Sr isotopes show affects of seawater alteration, but samples with 87Sr/86Sr 8.0 appear to preserve magmatic compositions and also indicate a common source for west-of-KPR basement and FAB. Trace element ratios resistant to seawater alteration (La/Yb, Lu/Hf, Zr/Nb, Sm/Nd) in west-of-KPR basement are generally more depleted than normal MORB and so also appear similar to FAB. At Site U1438, only andesite sills intruding sedimentary rocks overlying the basement have subduction-influenced geochemical characteristics (εNd ∼ 6.6, εHf ∼ 13.8, La/Yb > 2.5, Nd/Hf ∼ 9). The key characteristic that unites drill site basement rocks west of KPR and FAB is the nature of their source, which is more depleted in lithophile trace elements than average MORB but with Hf, Nd, and Pb isotope ratios that are common in MORB. The lithophile element-depleted nature of FAB has been linked to initiation of IBM subduction in the Eocene, but Sm-Nd model ages and errorchron relationships in Site U1438 basement indicate that the depleted character of the rocks is a regional characteristic that was produced well prior to the time of subduction initiation and persists today in the source of modern IBM arc volcanic rocks with

Rock pushing and sampling under rocks on Mars

Science.gov (United States)

Moore, H.J.; Liebes, S.; Crouch, D.S.; Clark, L.V.

1978-01-01

Viking Lander 2 acquired samples on Mars from beneath two rocks, where living organisms and organic molecules would be protected from ultraviolet radiation. Selection of rocks to be moved was based on scientific and engineering considerations, including rock size, rock shape, burial depth, and location in a sample field. Rock locations and topography were established using the computerized interactive video-stereophotogrammetric system and plotted on vertical profiles and in plan view. Sampler commands were developed and tested on Earth using a full-size lander and surface mock-up. The use of power by the sampler motor correlates with rock movements, which were by plowing, skidding, and rolling. Provenance of the samples was determined by measurements and interpretation of pictures and positions of the sampler arm. Analytical results demonstrate that the samples were, in fact, from beneath the rocks. Results from the Gas Chromatograph-Mass Spectrometer of the Molecular Analysis experiment and the Gas Exchange instrument of the Biology experiment indicate that more adsorbed(?) water occurs in samples under rocks than in samples exposed to the sun. This is consistent with terrestrial arid environments, where more moisture occurs in near-surface soil un- der rocks than in surrounding soil because the net heat flow is toward the soil beneath the rock and the rock cap inhibits evaporation. Inorganic analyses show that samples of soil from under the rocks have significantly less iron than soil exposed to the sun. The scientific significance of analyses of samples under the rocks is only partly evaluated, but some facts are clear. Detectable quantities of martian organic molecules were not found in the sample from under a rock by the Molecular Analysis experiment. The Biology experiments did not find definitive evidence for Earth-like living organisms in their sample. Significant amounts of adsorbed water may be present in the martian regolith. The response of the soil

The cataclasis in the crystalline basement of Northern Switzerland

International Nuclear Information System (INIS)

Meyer, J.

1987-01-01

In the crystalline basement of Northern Switzerland two main phases of cataclastic deformation can be distinguished: a 'cataclasis 1' in a higher temperature hydrothermal regime, as a consequence of tectonic and magmatic-hydrothermal events in Upper Carboniferous time and a lower temperature 'cataclasis 2', which can be related to Permian tectonics at the northern margin of the Paleozoic Konstanz-Frick trough. These cataclases are interpreted as a result of longlasting and complex tectonic processes at shallow crustal levels. (author) 30 refs., 4 figs

Risk of a large amount of high-radioactive contaminated water leaking into the reactor building basement of Fukushima Daiichi nuclear power station

International Nuclear Information System (INIS)

Ebisawa, Toru; Sawai, Masako

2013-01-01

In November 2012 about one and half year after the accident at units 1, 2 and 3 of Fukushima Daiichi nuclear power station, some 405 m 3 /day cooling water was being injected into the melt damaged core and leaked as highly-radioactive contaminated water from damaged lower part of containment into the basement of turbine hall. To treat a large amount of contaminated water in the basement, waste processing plant to remove cesium was installed in June 2011 with desalination plant, which produced clean water for circulating coolant system of damaged nuclear fuel while the rest went to storage. Radioactivity of contaminated water in the basement accumulated at initial almost 80 days of the accident was evaluated about 20% for Cs-137 of core inventory of units 1, 2 and 3 and 2.3% for Sr-90 of core inventory of units 2 and 3. Sr-90 from unit 1 was not released into the basement and almost remained at suppression chamber. By November 2012, Cs-137 released into the basement was evaluated to total about 40% of core inventory and stored contaminated water amounted to about 360 kilotons, while Cs-137 released into the atmosphere was estimated about 3.6% of core inventory with its one third contributed for land contamination. Sr-90 released into the basement was estimated as 6.3% or 4.4% of core inventory based on Sr-90 measured activity of treated water in December or September 2011 with stored contaminated water of 300 kilotons. Cs-137 and Sr-90 contaminated water kept continuously releasing into the basement as long as melt damaged core existed and cooling water washed out Cs-137 and Sr-90 attached on containment walls. Safe store of released radioactivity was highly important and acquired important data was recommended to publish for check and review. (T. Tanaka)

Rb/Sr geochronology in whole rocks and minerals of the Cumaru granodiorite, Serra dos Gradaus, Para state, Brazil

International Nuclear Information System (INIS)

Lafon, J.M.; Scheller, T.; Pereira, E.D.; Macambira, J.B.

1990-01-01

The Cumaru granodiorite occurs in the Serra dos Gradaus region, southeastern part of the Metallogenic Province of Carajas, Para. Rb-Sr systematics have been provided in whole rocks and minerals for samples of the Cumaru granodiorite thus an age of 2543 ± 53 Ma, with an initial isotopic ratio of 0.70311 ± 34 (MSWD+1.87) was obtained for whole rocks samples. Taking in account that these rocks are not affected by metamorphism and/or deformation, we consider the age of 2543 ± 53 Ma as an emplacement age corresponding to the crystallization of the body. Such an age confirms the existence of a late Archaean plutonic event in the Serra dos Gradaus area and the interpretation of the Cumaru granodiorite as a contemporaneous and cogenetic body of the Juruena type granites (Ca. 2000 Ma old), as proposed previously, must be definitively abandoned. Therefore, Archaean ages for the greenstone belt sequence (Gradaus group) as well as for the Xingu complex in this area are also confirmed, although by indirect evidence. The age obtained implies that the latter represents an Archaean metamorphic basement in the Serra dos Gradaus region rather than the reworking of the late archaean granitics rocks during the Transmazonian orogenic event. The initial isotopic ratio of 0.70311 ± 34 is close to a mantellic or low time of crustal residence source material ratios at the end of Archaean times. Therefore, comparison with isotopic initial ratios of other granitic rocks which occur in the Rio Maria region identifies an evolution line with a Rb-Sr ratio of 0.25 for a crustal source material that would have separated from mantle about 2.8 Ga ago. (author)

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.

Petrographic and EMP study of metamorphic rocks from the Variscan basement of Dinarides (Vranica Mountains, Bosnia and Herzegovina)

Energy Technology Data Exchange (ETDEWEB)

Hrvanovic, S [Department of Mineralogy and Petrology, Faculty of Natural Sciences, Comenius University, 84215 Bratislava (Slovakia)

2012-04-25

The Vranica Mountains are located in the middle part of Bosnia and Herzegovina or in the southeastern part of the Mid - Bosnian schist Mountains (MBSM). The Mid - Bosnian schist Mountains represent one of the largest allochtonous Paleozoic terranes in the Dinarides. This region is characterized by a multistage geodynamic evolution. The presented results concern Variscan metamorphism of the Silur-Devonian protolith formations that occurred mainly during the Early Carboniferous in LT/MP greenschist facies. Petrographical description of metamorphic rocks is completed by EMPA of muscovite, chlorite and chloritoid. The Early Alpine metamorphic overprint is related to the closure of a Tethyan Basin and Early Cretaceous collision of the Adria microplate with the Tissia-Moesia continental Blocks. The Neo-Alpine metamorphic overprint occurred due to the collision of the African and Euroasian Plates. (authors)

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.

to Dept. of Science & Technology, New Delhi for granting the Junior Research Fel- lowship through Inspire Programme. This is NIO (CSIR) contribution no. 7132. References Aftalion M, Bowes D R, Dash B and Dempster T J 1988 Late proterozoic charnockites... anomaly map in figure 1. Keywords. Marine magnetic anomalies; offshore K–G basin; magnetic basement; extension of EGMB geology; continent– oceanic boundary. J. Earth Syst. Sci. 125, No. 3, April 2016, pp. 663–668 c© Indian Academy of Sciences 663 664 V...

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.

"We Dominate the Basement!": How Asian American Girls Construct a Borderland Community

Science.gov (United States)

Tokunaga, Tomoko

2016-01-01

This article, based on two years of ethnographic fieldwork, explores the ways in which eight Asian American immigrant high school girls construct a borderland community, which they call the "Basement Group," after the place where they gather at school. While the girls struggle with displacement in the borderlands, including isolation in…

Late Archaean-early Proterozoic source ages of zircons in rocks from the Paleozoic orogen of western Galicia, NW Spain

Energy Technology Data Exchange (ETDEWEB)

Kuijper, R P; Priem, H N.A. [Laboratorium voor Isotopen-Geologie, Amsterdam (Netherlands); Den Tex, E [Rijksuniversiteit Utrecht (Netherlands). Inst. voor Aardwetenschappen

1982-08-01

U-Pb data are reported for nine suites of zircons and three monazites from the Paleozoic orogen in western Galicia: one paragneiss and six orthogneisses from the early Paleozoic basement, and two Carboniferous (ca. 310 Ma old) intrusions of two-mica granite. New whole-rock Rb-Sr analyses, along with earlier data, indicate an age of ca. 470-440 Ma (Ordovician) for the emplacement of the granitic precursors of the orthogneisses. Monazite from the paragneiss also yields an U-Pb age of ca. 470 Ma. From the high initial /sup 87/Sr//sup 86/Sr ratios an involvement of Precambrian continental crust material is evident in the generation of the early Paleozoic suite of granites, while the zircon U-Pb data give evidence of the presence of about 3.0-2.0 Ga old (late Archaean-early Proterozoic) components in the source material. Zircons from the oldest sedimentary rocks in the area, now present as catazonal paragneisses and a likely source for the granites, likewise reveal a provenance age of 3.0-2.0 Ga.

Comparison of different digital elevation models and satellite imagery for lineament analysis: Implications for identification and spatial arrangement of fault zones in crystalline basement rocks of the southern Black Forest (Germany)

Science.gov (United States)

Meixner, J.; Grimmer, J. C.; Becker, A.; Schill, E.; Kohl, T.

2018-03-01

first order results of the spatial arrangement of critically stressed faults in crystalline basement rocks.

HeatBar Final Report 2010, Basement Heat Generation and Heat Flow in the western Barents Sea - importance for hydrocarbon systems

International Nuclear Information System (INIS)

Pascal, Christophe; Balling, Niels; Barrere, Cecile; Davidsen, Boerre; Ebbing, Joerg; Elvebakk, Harald; Mesli, Melani; Roberts, David; Slagstad, Trond; Willemoes-Wissing, Bjoern

2011-01-01

The HeatBar project aimed to determine the relative proportion of heat originating in the basement of the western Barents Sea and, as such, followed the methodologies and scientific approach developed in the course of the 2005-2008 Kontiki Project. We proposed to shed new lights on the thermal state of the basins of the western Barents Sea by (1) determining the heat flow and the relative content in heat-producing elements of the basement onshore northern Norway, (2) building 3D structural models of the basement offshore based on extensive geophysical information and (3) building 3D thermal models of the basins offshore. The present report summarizes the work accomplished in the framework of the project since 2006.(Au)

Estimating the Wet-Rock P-Wave Velocity from the Dry-Rock P-Wave Velocity for Pyroclastic Rocks

Science.gov (United States)

Kahraman, Sair; Fener, Mustafa; Kilic, Cumhur Ozcan

2017-07-01

Seismic methods are widely used for the geotechnical investigations in volcanic areas or for the determination of the engineering properties of pyroclastic rocks in laboratory. Therefore, developing a relation between the wet- and dry-rock P-wave velocities will be helpful for engineers when evaluating the formation characteristics of pyroclastic rocks. To investigate the predictability of the wet-rock P-wave velocity from the dry-rock P-wave velocity for pyroclastic rocks P-wave velocity measurements were conducted on 27 different pyroclastic rocks. In addition, dry-rock S-wave velocity measurements were conducted. The test results were modeled using Gassmann's and Wood's theories and it was seen that estimates for saturated P-wave velocity from the theories fit well measured data. For samples having values of less and greater than 20%, practical equations were derived for reliably estimating wet-rock P-wave velocity as function of dry-rock P-wave velocity.

Observations of hydrotectonic stress/strain events at a basement high at the Nicoya outer rise

Science.gov (United States)

Tryon, M. D.; Brown, K. M.

2005-12-01

There is substantial and growing evidence from heat flow and coring investigations that the oceanic plate off Costa Rica is highly hydrologically active and that this activity is responsible for one of the most anomalously cold thermal environments encountered in the oceanic environment. Recent work by Fisher, et al. has identified limited regions above certain topographic highs with extremely high heat flows. Pore water profiles from cores above these thinly sedimented basement highs suggest upward flow on the order of ~1 cm/yr. These highs may be the principal regions of out-flow from the basement in this region and, thus, can potentially be used to constrain the general level of hydrologic activity. The nine Chemical and Aqueous Transport (CAT) meters we deployed at one of the highest heatflow sites provide a temporal record of both in-flow and out-flow of aqueous fluids at rates as low as 0.1 mm/yr. Our objective was to provide a direct measurement of long term flow rates to address the following questions: (1) What are the characteristic fluid fluxes at basement highs of the low heat flow region of the northern Costa Rican incoming plate, and (2) is this flow temporally variable? The results of the instrument deployments agree quite closely in general with the coring results in that the background rates are on the order of 1 cm/yr or less. There is, however, considerable detail in the temporal records which suggest small scale tectonic stress transients causing temporary increases in flow rate. While this is certainly not an area of major tectonic activity, the site is located at the top of the outer rise where one would expect bending-related stress and fault reactivation to occur. The CAT meters are capable of detecting minute strain events in the underlying sediments and therefore may be detecting small localized strain events. Two periods of increased flow lasting a few weeks each occur during the 5 month deployment and are indicated on all of the

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

'Escher' Rock

Science.gov (United States)

2004-01-01

[figure removed for brevity, see original site] Chemical Changes in 'Endurance' Rocks [figure removed for brevity, see original site] Figure 1 This false-color image taken by NASA's Mars Exploration Rover Opportunity shows a rock dubbed 'Escher' on the southwestern slopes of 'Endurance Crater.' Scientists believe the rock's fractures, which divide the surface into polygons, may have been formed by one of several processes. They may have been caused by the impact that created Endurance Crater, or they might have arisen when water leftover from the rock's formation dried up. A third possibility is that much later, after the rock was formed, and after the crater was created, the rock became wet once again, then dried up and developed cracks. Opportunity has spent the last 14 sols investigating Escher, specifically the target dubbed 'Kirchner,' and other similar rocks with its scientific instruments. This image was taken on sol 208 (Aug. 24, 2004) by the rover's panoramic camera, using the 750-, 530- and 430-nanometer filters. The graph above shows that rocks located deeper into 'Endurance Crater' are chemically altered to a greater degree than rocks located higher up. This chemical alteration is believed to result from exposure to water. Specifically, the graph compares ratios of chemicals between the deep rock dubbed 'Escher,' and the more shallow rock called 'Virginia,' before (red and blue lines) and after (green line) the Mars Exploration Rover Opportunity drilled into the rocks. As the red and blue lines indicate, Escher's levels of chlorine relative to Virginia's went up, and sulfur down, before the rover dug a hole into the rocks. This implies that the surface of Escher has been chemically altered to a greater extent than the surface of Virginia. Scientists are still investigating the role water played in influencing this trend. These data were taken by the rover's alpha particle X-ray spectrometer.

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

DEFF Research Database (Denmark)

Zhou, Lingli; Friis, Henrik; Yang, Tian

2017-01-01

show a depletion of major elements in the following order: Na N Ca N Mg N Si; Al and Ti are immobile and stay constant; K shows sample dependent enrichment or depletion; Fe is slightly enriched. The Cambrian sandstone overlying the basement in the Borggård borehole, assigned to the Gadeby Member...... 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 G...

A record of spontaneous subduction initiation in the Izu-Bonin-Mariana arc

Science.gov (United States)

Arculus, Richard J.; Ishizuka, Osamu; Bogus, Kara A.; Gurnis, Michael; Hickey-Vargas, Rosemary; Aljahdali, Mohammed H.; Bandini-Maeder, Alexandre N.; Barth, Andrew P.; Brandl, Philipp A.; Drab, Laureen; Do Monte Guerra, Rodrigo; Hamada, Morihisa; Jiang, Fuqing; Kanayama, Kyoko; Kender, Sev; Kusano, Yuki; Li, He; Loudin, Lorne C.; Maffione, Marco; Marsaglia, Kathleen M.; McCarthy, Anders; Meffre, Sebastién; Morris, Antony; Neuhaus, Martin; Savov, Ivan P.; Sena, Clara; Tepley, Frank J., III; van der Land, Cees; Yogodzinski, Gene M.; Zhang, Zhaohui

2015-09-01

The initiation of tectonic plate subduction into the mantle is poorly understood. If subduction is induced by the push of a distant mid-ocean ridge or subducted slab pull, we expect compression and uplift of the overriding plate. In contrast, spontaneous subduction initiation, driven by subsidence of dense lithosphere along faults adjacent to buoyant lithosphere, would result in extension and magmatism. The rock record of subduction initiation is typically obscured by younger deposits, so evaluating these possibilities has proved elusive. Here we analyse the geochemical characteristics of igneous basement rocks and overlying sediments, sampled from the Amami Sankaku Basin in the northwest Philippine Sea. The uppermost basement rocks are areally widespread and supplied via dykes. They are similar in composition and age--as constrained by the biostratigraphy of the overlying sediments--to the 52-48-million-year-old basalts in the adjacent Izu-Bonin-Mariana fore-arc. The geochemical characteristics of the basement lavas indicate that a component of subducted lithosphere was involved in their genesis, and the lavas were derived from mantle source rocks that were more melt-depleted than those tapped at mid-ocean ridges. We propose that the basement lavas formed during the inception of Izu-Bonin-Mariana subduction in a mode consistent with the spontaneous initiation of subduction.

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.

Embryoid body attachment to reconstituted basement membrane induces a genetic program of epithelial differentiation via jun N-terminal kinase signaling.

Science.gov (United States)

Ho, Hoang-Yen; Moffat, Ryan C; Patel, Rupal V; Awah, Franklin N; Baloue, Kaitrin; Crowe, David L

2010-09-01

Embryonic stem (ES) cells are derived from early stage mammalian embryos and have broad developmental potential. These cells can be manipulated experimentally to generate cells of multiple tissue types which could be important in treating human diseases. The ability to produce relevant amounts of these differentiated cell populations creates the basis for clinical interventions in tissue regeneration and repair. Understanding how embryonic stem cells differentiate also can reveal important insights into cell biology. A previously reported mouse embryonic stem cell model demonstrated that differentiated epithelial cells migrated out of embryoid bodies attached to reconstituted basement membrane. We used genomic technology to profile ES cell populations in order to understand the molecular mechanisms leading to epithelial differentiation. Cells with characteristics of cultured epithelium migrated from embryoid bodies attached to reconstituted basement membrane. However, cells that comprised embryoid bodies also rapidly lost ES cell-specific gene expression and expressed proteins characteristic of stratified epithelia within hours of attachment to basement membrane. Gene expression profiling of sorted cell populations revealed upregulation of the BMP/TGFbeta signaling pathway, which was not sufficient for epithelial differentiation in the absence of basement membrane attachment. Activation of c-jun N-terminal kinase 1 (JNK1) and increased expression of Jun family transcription factors was observed during epithelial differentiation of ES cells. Inhibition of JNK signaling completely blocked epithelial differentiation in this model, revealing a key mechanism by which ES cells adopt epithelial characteristics via basement membrane attachment. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Implanted of Pb-Pb methodology in whole rock: examples of use in Carajas Mineral Province, Para State

International Nuclear Information System (INIS)

Rodrigues, Elizabeth Maria Soares.

1992-01-01

This work presents the first data obtained by Pb-Pb systematics in whole rock and separated minerals. The Pb isotopic compositions of samples were determined by mass spectrometry. The average analytical errors of the ratios 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 209 Pb were 0.10%, 0.12% and 0.15%, respectively. The age calculation in the 207 Pb/ 204 Pb x 206 Pb/ 204 Pb diagram was obtained by York (1969) and Ludwig (1900). In order to verify the efficiency of the implanted methodology, 5 rocks from of the Carajas Mineral Province and Sao Felix do Xingu Region were dated. The Velho Guilherme granite, intrusive into the granite-greenstone terrains of Tucuma Region (PA), provided a Pb-Pb crystallization age (11 WR,2 FELD) of 1874 ± 15 Ma with MSWD = 1.53 and μ 1 = 8.9 ± 0.07 (single stage). The Granulitic rocks of Pium complex (Catete area), located at the SW of Serra dos Carajas, provided a Pb-Pb age of 3044 ± 64 Ma with MSWD = 28.72 and μ 1 = 9.2 ± .58. In the Rio Maria Region, Mata Surrao monzogranite which cross cut the gneiss basement and associated to the greenstone belts, defined a crystallization Pb-Pb (8 WR) age of 2876 ± 10 Ma with MSWD = 3.71 and μ 1 = 8.2 ± 0.11. In the same region, the Metabasalts of the Identidade greenstone belt, (Andorinhas supergroup), showed a Pb-Pb age in whole rock (7 samples) of 3400 ± 109 Ma with MSWD = 7.97 and μ 1 = 9.6 ± 1.44. Five whole rock samples from metadacites, located in the central part of the Identidade greenstone, provided a crystallization age of 2944 ± 88 Ma with MSWD 31.52 and μ 1 = 8.2 ± .70. The results obtained in this work emphasize the high potentiality of the Pb-Pb method of dating to obtain crystallization ages of Precambrian rocks. (author). 69 refs., 23 figs., 12 tabs

Agrin is a major heparan sulfate proteoglycan in the human glomerular basement membrane

NARCIS (Netherlands)

Groffen, Alexander J.; Ruegg, Markus A.; Dijkman, Henri; Van De Velden, Thea J.; Buskens, Carin A.; Van Den Born, Jacob; Assmann, Karel J.; Monnens, Leo A.; Veerkamp, Jacques H.; Van Den Heuvel, Lambert P.

Agrin is a heparan sulfate proteoglycan (HSPG) that is highly concentrated in the synaptic basal lamina at the neuromuscular junction (NMJ). Agrin-like immunoreactivity is also detected outside the NMJ. Here we show that agrin is a major HSPG component of the human glomerular basement membrane

Regional stratigraphy, sedimentology, and tectonic significance of Oligocene-Miocene sedimentary and volcanic rocks, northern Baja California, Mexico

Science.gov (United States)

Dorsey, Rebecca J.; Burns, Beverly

1994-01-01

Upper Oligocene (?) to middle Miocene sedimentary and volcanic rocks in northern Baja California were deposited along the western margin of North America during subduction of the Guadalupe plate and southward migration of the Rivera Triple Junction. Regional mapping and compilation of stratigraphic data reveal a sequence of three regionally traceable stratigraphic units. (1) Oligocene (?) to lower Miocene Mesa Formation: basal quartz-rich fluvial sandstone, grus, conglomerate, and accessory facies, whose detrital compositions reflect the composition of local pre-Tertiary basement rock. (2) Lower to middle Miocene Comondú Formation: laterally variable sequence of volcaniclastic conglomerate, breccia, sandstone, tuff and minor volcanic flow units. (3) Widespread mesa-capping rhyolite tuff, typically welded and crystal-rich, probably upper Miocene in age. The Mesa Formation overlies a highly irregular and deeply dissected erosional surface developed on pre-Tertiary basement rock. The shift from pre-Mesa erosion to widespread (though localized) deposition and valley-filling records the final phase of late Cretaceous to middle Tertiary regional subsidence and eastward transgression that resulted from slow cooling and thermal contraction of Cretaceous arc crust during a temporal gap in magmatic activity along the western Cordilleran margin. Nonmarine sediments of the Mesa Formation were deposited in small, steep-walled paleovalleys and basins that gradually filled and evolved to form through-going, low-energy ephemeral stream systems. The gradational upward transition from the Mesa to Comondú Formation records the early to middle Miocene onset of subduction-related arc magmatism in eastern Baja California and related westward progradation of alluvial volcaniclastic aprons shed from high-standing eruptive volcanic centers. Pre-existing streams were choked with the new influx of volcanic detritus, causing the onset of rapid sediment deposition by stream flows and dilute

Carbonate rocks of the Seward Peninsula, Alaska: Their correlation and paleogeographic significance

Science.gov (United States)

Dumoulin, Julie A.; Harris, Alta; Repetski, John E.

2014-01-01

Paleozoic carbonate strata deposited in shallow platform to off-platform settings occur across the Seward Peninsula and range from unmetamorphosed Ordovician–Devonian(?) rocks of the York succession in the west to highly deformed and metamorphosed Cambrian–Devonian units of the Nome Complex in the east. Faunal and lithologic correlations indicate that early Paleozoic strata in the two areas formed as part of a single carbonate platform. The York succession makes up part of the York terrane and consists of Ordovician, lesser Silurian, and limited, possibly Devonian rocks. Shallow-water facies predominate, but subordinate graptolitic shale and calcareous turbidites accumulated in deeper water, intraplatform basin environments, chiefly during the Middle Ordovician. Lower Ordovician strata are mainly lime mudstone and peloid-intraclast grainstone deposited in a deepening upward regime; noncarbonate detritus is abundant in lower parts of the section. Upper Ordovician and Silurian rocks include carbonate mudstone, skeletal wackestone, and coral-stromatoporoid biostromes that are commonly dolomitic and accumulated in warm, shallow to very shallow settings with locally restricted circulation. The rest of the York terrane is mainly Ordovician and older, variously deformed and metamorphosed carbonate and siliciclastic rocks intruded by early Cambrian (and younger?) metagabbros. Older (Neoproterozoic–Cambrian) parts of these units are chiefly turbidites and may have been basement for the carbonate platform facies of the York succession; younger, shallow- and deep-water strata likely represent previously unrecognized parts of the York succession and its offshore equivalents. Intensely deformed and altered Mississippian carbonate strata crop out in a small area at the western edge of the terrane. Metacarbonate rocks form all or part of several units within the blueschist- and greenschist-facies Nome Complex. The Layered sequence includes mafic meta¬igneous rocks and

Geology and sratigraphy of the Cainozoic Sedimantary Rocks in the Kale-Kurbalık Area, Denizli, Southwestern Turkey

Directory of Open Access Journals (Sweden)

H.Yavuz HAKYEMEZ

1989-06-01

Full Text Available In this work, the geological and stratigraphical characteristics of the Cainozoic sedimentary rocks exposed at the Kale-Kurbalık (SW Denizli area have been investigated. In the study area the Palaeozoic and Mesozoic rocks form the basement rocks and are overlain by the Oligocene to the Quaternary aged sedimentary rocks. The Tertiary rocks have been considered in two groups, namely the Akçay group and the Muğla group. The Oligocene to the Burdigalian aged Akçay group is represented by the Karadere, Mortuma, Yenidere, Künar and Kale formations. During this time interval, mostly the terrestrial fine and coarse clastics were deposited, but in the last stage of this time shallow marine carbonates were sedimented on the some parts of the region. There is an angular unconformity between the Mortuma and the Yenidere formations of the Akçay group; others are conformable to each other. The Akçay group is 4100 meter thick. The Upper Astarasian (Middle Miocene to Pliocene aged Muğla group which overlies the Akçay group uncorformably is formed of the Sekköy, Yatağan and Milet formations. During this time interval, the lacustrine siltstones and carbonates and the terrestrial coarse elastics were deposited. The formations of the Muğla group are conformable and gradational to each other. The Muğla group is 550 meter thick. The Quaternary deposits have been considered in two units, namely "Lower" and "Upper" Quaternary sediments. Only the Mortuma formation of all units of the study area is gently folded, but others have low degree dips. Tectonic activity has played a big important role in the forming of the various sedimentary basins which have been generated since the beginning of the Oligocene up to the present.

The Caledonian tectonomagmatic evolution of the Orkney Islands, Scotland

OpenAIRE

Bjerga, Audun Dalene

2017-01-01

The geology of the Orkney Islands is dominated by well-studied Devonian sedimentary rocks deposited in the Orcadian basin. However, on the islands of Mainland Orkney and Graemsay there are small, relatively poorly studied outcrops of the underlying basement. Based on comparison with rocks in mainland Scotland this basement has been suggested to comprise pre-Caledonian para-gneisses and Caledonian granites. This has, however, never been documented. Here the contact relationships in the basemen...

Basement membrane-specific chondroitin sulfate proteoglycan is abnormally associated with the glomerular capillary basement membrane of diabetic rats

DEFF Research Database (Denmark)

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

1994-01-01

exception being the normal glomerular capillary basement membrane (GBM), where it is absent. In the present study of mature kidneys we examined the distribution of BM-CSPG in streptozocin-induced diabetes mellitus in rats. We found BM-CSPG atypically associated with the GBM of diabetic animals as early as 1...... month after induction of diabetes mellitus. Immunoelectron microscopy (IEM) of affected capillary loops showed BM-CSPG present in the subendothelial matrix in areas of GBM thickening and absent in areas where the GBM appears to be of normal thickness. Moreover, the association of BM-CSPG with regions...... of the pericapillary GBM affects the morphology of the capillary endothelial cells within these areas, directly displacing the cell body from the GBM proper and causing loss of fenestrae. These new data on BM-CSPG distribution reflect abnormal glomerular extracellular matrix protein biosynthesis/turnover in diabetes...

Rock fragmentation

Energy Technology Data Exchange (ETDEWEB)

Brown, W.S.; Green, S.J.; Hakala, W.W.; Hustrulid, W.A.; Maurer, W.C. (eds.)

1976-01-01

Experts in rock mechanics, mining, excavation, drilling, tunneling and use of underground space met to discuss the relative merits of a wide variety of rock fragmentation schemes. Information is presented on novel rock fracturing techniques; tunneling using electron beams, thermocorer, electric spark drills, water jets, and diamond drills; and rock fracturing research needs for mining and underground construction. (LCL)

Geology and Geochemistry of Magmatic Rocks from the Southern Part of the Kyushu-Palau Ridge in the Philippine Sea

Science.gov (United States)

Lelikov, E. P.; Sedin, V. T.; Pugachev, A. A.

2018-03-01

The paper reports the results of a geochemical study of volcanogenic rocks from the southern part of the Kyushu-Palau Ridge. Volcanic structures, such as plateaulike rises, mountain massifs, and single volcanoes, are the major relief-forming elements of the southern part of the Kyushu-Palau Ridge. They are divided into three types according to the features of the relief and geological structure: shield, cone-shaped, and dome-shaped volcanoes. The ridge was formed on oceanic crust in the Late Mesozoic and underwent several stages of evolution with different significance and application of forces (tension and compression). Change in the geodynamic conditions during the geological evolution of the ridge mostly determined the composition of volcanic rocks of deep-mantle nature. Most of the ridge was formed by the Early Paleogene under geodynamic conditions close to the formation of oceanic islands (shield volcanoes) under tension. The island arc formed on the oceanic basement in the compression mode in the Late Eocene-Early Oligocene. Dome-shaped volcanic edifices composed of alkaline volcanic rocks were formed in the Late Oligocene-Early Miocene under tension. Based on the new geochemical data, detailed characteristics of volcanic rocks making up the shield, cone-shape, and dome-shape stratovolcanoes resulting in the features of these volcanic edifices are given for the first time. Continuous volcanism (with an age from the Cretaceous to the Late Miocene and composition from oceanic tholeiite to calc-alkaline volcanites of the island arc type) resulting in growth of the Earth's crust beneath the Kyushu-Palau Ridge was the major factor in the formation this ridge.

Southern Brasilia Belt (SE Brazil): tectonic discontinuities, K-Ar data and evolution during the Neoproterozoic Brasiliano orogeny

International Nuclear Information System (INIS)

Valeriano, Claudio Morrison de; Teixeira, Wilson; Simoes, Luiz Sergio Amarante; Heilbron, Monica

2000-01-01

This paper focuses the tectonic evolution of the southern brasilia belt, with emphasis on the Furnas segment, along the 21 deg C S parallel. The uppermost structural unit (Passos Nappe - PN) comprises a highly deformed metasedimentary succession interpreted as a fragment of the Neoproterozoic passive margin of western Sao francisco craton. An inverted metamorphic gradient ranging from greensvhits to lower granulite facies of medium to high-pressure regime characterizes the PN as relict of a subduction zone. The External Domain display a complex imbrication of basement rocks (Archean Piumhi greenstones, a turbiditic gaywacke succession and a calc-alkaline granitoid suite) with undated siliciclast low-grade metasedimentary rocks. The Sao Francisco Craton (SFC) comprises pre-1.8 Ga basement rocks covered by anchimetamorphic Neoproterozoic carbonatic shallow marine platform deposits of the Bambui group. The Brasiliano thrust stacking generated a coarse clastic influx of molassic character on the foreland zone of Sao Francisco Craton, coeval with the exhumation of the External Domain thrust sheets. New K-Ar determinations on mineral separates are presented an interpreted among previous data. The SFC basement rocks display Paleo-to Meesoproterozoic cooling ages. The allochthonous units, in contrast, display K-Ar ages within the 560-675 Ma range. Brasiliano thrust stacking is therefore interpreted to have taken place onto a cold Sao Francisco craton foreland, in a thin-skinned style, as basement rocks were not heated enough to have their-K-ar systems reset during the allochthony. (author)

Rock mechanics for hard rock nuclear waste repositories

International Nuclear Information System (INIS)

Heuze, F.E.

1981-09-01

The mined geologic burial of high level nuclear waste is now the favored option for disposal. The US National Waste Terminal Storage Program designed to achieve this disposal includes an extensive rock mechanics component related to the design of the wastes repositories. The plan currently considers five candidate rock types. This paper deals with the three hard rocks among them: basalt, granite, and tuff. Their behavior is governed by geological discontinuities. Salt and shale, which exhibit behavior closer to that of a continuum, are not considered here. This paper discusses both the generic rock mechanics R and D, which are required for repository design, as well as examples of projects related to hard rock waste storage. The examples include programs in basalt (Hanford/Washington), in granitic rocks (Climax/Nevada Test Site, Idaho Springs/Colorado, Pinawa/Canada, Oracle/Arizona, and Stripa/Sweden), and in tuff

Elastic Rock Heterogeneity Controls Brittle Rock Failure during Hydraulic Fracturing

Science.gov (United States)

Langenbruch, C.; Shapiro, S. A.

2014-12-01

For interpretation and inversion of microseismic data it is important to understand, which properties of the reservoir rock control the occurrence probability of brittle rock failure and associated seismicity during hydraulic stimulation. This is especially important, when inverting for key properties like permeability and fracture conductivity. Although it became accepted that seismic events are triggered by fluid flow and the resulting perturbation of the stress field in the reservoir rock, the magnitude of stress perturbations, capable of triggering failure in rocks, can be highly variable. The controlling physical mechanism of this variability is still under discussion. We compare the occurrence of microseismic events at the Cotton Valley gas field to elastic rock heterogeneity, obtained from measurements along the treatment wells. The heterogeneity is characterized by scale invariant fluctuations of elastic properties. We observe that the elastic heterogeneity of the rock formation controls the occurrence of brittle failure. In particular, we find that the density of events is increasing with the Brittleness Index (BI) of the rock, which is defined as a combination of Young's modulus and Poisson's ratio. We evaluate the physical meaning of the BI. By applying geomechanical investigations we characterize the influence of fluctuating elastic properties in rocks on the probability of brittle rock failure. Our analysis is based on the computation of stress fluctuations caused by elastic heterogeneity of rocks. We find that elastic rock heterogeneity causes stress fluctuations of significant magnitude. Moreover, the stress changes necessary to open and reactivate fractures in rocks are strongly related to fluctuations of elastic moduli. Our analysis gives a physical explanation to the observed relation between elastic heterogeneity of the rock formation and the occurrence of brittle failure during hydraulic reservoir stimulations. A crucial factor for understanding

Rock.XML - Towards a library of rock physics models

Science.gov (United States)

Jensen, Erling Hugo; Hauge, Ragnar; Ulvmoen, Marit; Johansen, Tor Arne; Drottning, Åsmund

2016-08-01

Rock physics modelling provides tools for correlating physical properties of rocks and their constituents to the geophysical observations we measure on a larger scale. Many different theoretical and empirical models exist, to cover the range of different types of rocks. However, upon reviewing these, we see that they are all built around a few main concepts. Based on this observation, we propose a format for digitally storing the specifications for rock physics models which we have named Rock.XML. It does not only contain data about the various constituents, but also the theories and how they are used to combine these building blocks to make a representative model for a particular rock. The format is based on the Extensible Markup Language XML, making it flexible enough to handle complex models as well as scalable towards extending it with new theories and models. This technology has great advantages as far as documenting and exchanging models in an unambiguous way between people and between software. Rock.XML can become a platform for creating a library of rock physics models; making them more accessible to everyone.

Role of 17 beta-estradiol on type IV collagen fibers volumetric density in the basement membrane of bladder wall.

Science.gov (United States)

de Fraga, Rogerio; Dambros, Miriam; Miyaoka, Ricardo; Riccetto, Cássio Luís Zanettini; Palma, Paulo César Rodrigues

2007-10-01

The authors quantified the type IV collagen fibers volumetric density in the basement membrane of bladder wall of ovariectomized rats with and without estradiol replacement. This study was conducted on 40 Wistar rats (3 months old) randomly divided in 4 groups: group 1, remained intact (control); group 2, submitted to bilateral oophorectomy and daily replacement 4 weeks later of 17 beta-estradiol for 12 weeks; group 3, sham operated and daily replacement 4 weeks later of sesame oil for 12 weeks; and group 4, submitted to bilateral oophorectomy and killed after 12 weeks. It was used in immunohistochemistry evaluation using type IV collagen polyclonal antibody to stain the fibers on paraffin rat bladder sections. The M-42 stereological grid system was used to analyze the fibers. Ovariectomy had an increase effect on the volumetric density of the type IV collagen fibers in the basement membrane of rat bladder wall. Estradiol replacement in castrated animals demonstrated a significative difference in the stereological parameters when compared to the castrated group without hormonal replacement. Surgical castration performed on rats induced an increasing volumetric density of type IV collagen fibers in the basement membrane of rats bladder wall and the estradiol treatment had a significant effect in keeping a low volumetric density of type IV collagen fibers in the basement membrane of rats bladder wall.

Application of Cauchy-type integrals in developing effective methods for depth-to-basement inversion of gravity and gravity gradiometry data

DEFF Research Database (Denmark)

Cai, Hongzhu; Zhdanov, Michael

2015-01-01

to be discretized for the calculation of gravity field. This was especially significant in the modeling and inversion of gravity data for determining the depth to the basement. Another important result was developing a novel method of inversion of gravity data to recover the depth to basement, based on the 3D...... Cauchy-type integral representation. Our numerical studies determined that the new method is much faster than conventional volume discretization method to compute the gravity response. Our synthetic model studies also showed that the developed inversion algorithm based on Cauchy-type integral is capable......One of the most important applications of gravity surveys in regional geophysical studies is determining the depth to basement. Conventional methods of solving this problem are based on the spectrum and/or Euler deconvolution analysis of the gravity field and on parameterization of the earth...

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

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

Antibody response against the glomerular basement membrane protein agrin in patients with transplant glomerulopathy.

NARCIS (Netherlands)

Joosten, S.A.; Sijpkens, Y.W.; Ham, V. van; Trouw, L.A.; Vlag, J. van der; Heuvel, L.P.W.J. van den; Kooten, C. van; Paul, L.C.

2005-01-01

Chronic allograft nephropathy (CAN) of renal allografts is still the most important cause of graft loss. A subset of these patients have transplant glomerulopathy (TGP), characterized by glomerular basement membrane (GBM) duplications, but of unknown etiology. Recently, a role for the immune system

Concerted regulation of retinal pigment epithelium basement membrane and barrier function by angiocrine factors.

Science.gov (United States)

Benedicto, Ignacio; Lehmann, Guillermo L; Ginsberg, Michael; Nolan, Daniel J; Bareja, Rohan; Elemento, Olivier; Salfati, Zelda; Alam, Nazia M; Prusky, Glen T; Llanos, Pierre; Rabbany, Sina Y; Maminishkis, Arvydas; Miller, Sheldon S; Rafii, Shahin; Rodriguez-Boulan, Enrique

2017-05-19

The outer blood-retina barrier is established through the coordinated terminal maturation of the retinal pigment epithelium (RPE), fenestrated choroid endothelial cells (ECs) and Bruch's membrane, a highly organized basement membrane that lies between both cell types. Here we study the contribution of choroid ECs to this process by comparing their gene expression profile before (P5) and after (P30) the critical postnatal period when mice acquire mature visual function. Transcriptome analyses show that expression of extracellular matrix-related genes changes dramatically over this period. Co-culture experiments support the existence of a novel regulatory pathway: ECs secrete factors that remodel RPE basement membrane, and integrin receptors sense these changes triggering Rho GTPase signals that modulate RPE tight junctions and enhance RPE barrier function. We anticipate our results will spawn a search for additional roles of choroid ECs in RPE physiology and disease.

Rock burst governance of working face under igneous rock

Science.gov (United States)

Chang, Zhenxing; Yu, Yue

2017-01-01

As a typical failure phenomenon, rock burst occurs in many mines. It can not only cause the working face to cease production, but also cause serious damage to production equipment, and even result in casualties. To explore how to govern rock burst of working face under igneous rock, the 10416 working face in some mine is taken as engineering background. The supports damaged extensively and rock burst took place when the working face advanced. This paper establishes the mechanical model and conducts theoretical analysis and calculation to predict the fracture and migration mechanism and energy release of the thick hard igneous rock above the working face, and to obtain the advancing distance of the working face when the igneous rock fractures and critical value of the energy when rock burst occurs. Based on the specific conditions of the mine, this paper put forward three kinds of governance measures, which are borehole pressure relief, coal seam water injection and blasting pressure relief.

Preliminary interpretation of isotopic studies of geothermal waters from the Beijing region (P.R. China)

International Nuclear Information System (INIS)

Keyan, Zheng; Da-Lei, Ma; Changfang, Xie; Shangyao, Huang; Jianghua, Feng; Jingshu, Wu

1982-01-01

Isotopic studies of thermal and cold surface waters sampled in Beijing region have shown that the thermal waters are meteoric waters which have been precipitated in the mountainous area lying to the NW of Beijing. ΔD and over distances of more than 150 km in Sinian basement rocks which are 3 to 5 km in the SE sector of the region. Significant 18 O exchange with basement rocks occurs in the Jizhong Depression about 60 km to the SE of Beijing. On a smaller scale, a SE flow of thermal waters in basement rocks in corroborated by Δ 34 S data for the Beijing area and the Beijing geothermal field. The Beijing geothermal field and other geothermal fields in the SE sector of the Beijing region are an example for low temperature systems where the heat is derived from a normal or slightly greater than normal, terrestrial heat flow

Uplift, Emergence, and Subsidence of the Gorda Escarpment Basement Ridge Offshore Cape Mendocino, CA

Science.gov (United States)

Hoover, Susan M.; Tréhu, Anne M.

2017-12-01

The Gorda Escarpment is a topographic step that characterizes the south side of the Mendocino Transform Fault east of 126oW and forms the northern edge of the Vizcaino Block. Seismic reflection data suggest that the basement beneath the northern edge of the Vizcaino is composed of east-west trending slivers of oceanic crust that form a 15 km wide band of buried ridges we call the Gorda Escarpment Basement Ridge (GEBR) to distinguish it from the northwest-trending basement structure that characterizes most of the Vizcaino Block. The history of uplift and subsidence of the GEBR is reconstructed by combining the seismic reflection profiles with age and lithological constraints from ODP Site 1022, gravity cores, and grab samples from the northern face of the Escarpment recovered using a remotely operated vehicle. Uplift of the GEBR began prior to 6 Ma, and it was above sea level 3.7-2.5 Ma. GEBR uplift and emergence coincided with sediment deposition on the southern flank of the GEBR that we interpret as indicative of strong upwelling and turbulence in the lee of a shallow ridge and island chain. A bright reflection, interpreted to be a sill, is observed south of the shallowest part of the GEBR. We speculate that this sill may reflect a larger, hidden intrusion at depth and that thermal expansion of the crust combined with tectonic forces to drive enhanced uplift of this segment of the plate boundary. The GEBR has been subsiding since 2.7 Ma, and its shallowest point is now 1,400 m below sea level.

Basement to surface expressions and critical factors in the genesis of unconformity-related deposits

International Nuclear Information System (INIS)

Potter, Eric

2014-01-01

Two subprojects: 1) Basement to surface expressions of deep mineralization and refinement of critical factors leading to the genesis of unconformity-related uranium deposits; and 2) Recognition of uranium ore system alteration signatures in complex terranes: IOCG vs albite-hosted uranium vs volcanic-hosted uranium.

ULTRASTRUCTURAL-CHANGES OF THE BASEMENT-MEMBRANE ZONE IN BENIGN LESIONS OF THE VOCAL FOLDS

NARCIS (Netherlands)

DIKKERS, FG; HULSTAERT, CE; OOSTERBAAN, JA; CERVERAPAZ, FJ

The basement membrane zone (BMZ) of the epithelium of the vocal folds was investigated electron microscopically in 10 patients suffering from various benign lesions and in 3 controls. Various defects were observed: a thickening by deposition of electron dense material, a loss of normal architecture,

For Those About to Rock : Naislaulajat rock-genressä

OpenAIRE

Herranen, Linda

2015-01-01

For those about to rock – naislaulajat rock-genressä antaa lukijalleen kokonaisvaltaisen käsityksen naisista rock-genressä: rockin historiasta, sukupuolittuneisuudesta, seksismistä, suomalaisten naislaulajien menestyksestä. Työn aineisto on koottu aihepiirin kirjallisuudesta ja alalla toimiville naislaulajille teetettyjen kyselyiden tuloksista. Lisäksi avaan omia kokemuksiani ja ajatuksiani, jotta näkökulma naisista rock-genressä tulisi esille mahdollisimman monipuolisesti. Ajatus aihees...

Proceedings of the 3. Canada-US rock mechanics symposium and 20. Canadian rock mechanics symposium : rock engineering 2009 : rock engineering in difficult conditions

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

This conference provided a forum for geologists, mining operators and engineers to discuss the application of rock mechanics in engineering designs. Members of the scientific and engineering communities discussed challenges and interdisciplinary elements involved in rock engineering. New geological models and methods of characterizing rock masses and ground conditions in underground engineering projects were discussed along with excavation and mining methods. Papers presented at the conference discussed the role of rock mechanics in forensic engineering. Geophysics, geomechanics, and risk-based approaches to rock engineering designs were reviewed. Issues related to high pressure and high flow water conditions were discussed, and new rock physics models designed to enhance hydrocarbon recovery were presented. The conference featured 84 presentations, of which 9 have been catalogued separately for inclusion in this database. tabs., figs.

De novo deposition of laminin-positive basement membrane in vitro by normal hepatocytes and during hepatocarcinogenesis

DEFF Research Database (Denmark)

Albrechtsen, R; Wewer, U M; Thorgeirsson, S S

1988-01-01

De novo formation of laminin-positive basement membranes was found to be a distinct morphologic feature of diethylnitrosamine/phenobarbital-induced hepatocellular carcinomas of the rat. The first appearance of extracellularly located laminin occurred in the preneoplastic liver lesions...... (corresponding to neoplastic nodules), and this feature became successively more prominent during the course of hepatocellular carcinoma development. Most groups of tumor cells were surrounded by laminin-positive basement membrane material. The laminin-positive material was also deposited along the sinusoids......, a location where no laminin was seen in normal rat liver. The amount of extractable laminin from hepatocellular carcinomas was significantly higher (approximately 100 ng per mg tissue) than that of normal liver tissue (less than 20 ng per mg). In vitro experiments demonstrated that normal and preneoplastic...

Geology along the Blue Ridge Parkway in Virginia

Science.gov (United States)

Carter, Mark W.; Southworth, C. Scott; Tollo, Richard P.; Merschat, Arthur J.; Wagner, Sara; Lazor, Ava; Aleinikoff, John N.

2017-01-01

Detailed geologic mapping and new SHRIMP (sensitive high-resolution ion microprobe) U-Pb zircon, Ar/Ar, Lu-Hf, 14C, luminescence (optically stimulated), thermochronology (fission-track), and palynology reveal the complex Mesoproterozoic to Quaternary geology along the ~350 km length of the Blue Ridge Parkway in Virginia. Traversing the boundary of the central and southern Appalachians, rocks along the parkway showcase the transition from the para-autochthonous Blue Ridge anticlinorium of northern and central Virginia to the allochthonous eastern Blue Ridge in southern Virginia. From mile post (MP) 0 near Waynesboro, Virginia, to ~MP 124 at Roanoke, the parkway crosses the unconformable to faulted boundary between Mesoproterozoic basement in the core of the Blue Ridge anticlinorium and Neoproterozoic to Cambrian metasedimentary and metavolcanic cover rocks on the western limb of the structure. Mesoproterozoic basement rocks comprise two groups based on SHRIMP U-Pb zircon geochronology: Group I rocks (1.2-1.14 Ga) are strongly foliated orthogneisses, and Group II rocks (1.08-1.00 Ga) are granitoids that mostly lack obvious Mesoproterozoic deformational features.Neoproterozoic to Cambrian cover rocks on the west limb of the anticlinorium include the Swift Run and Catoctin Formations, and constituent formations of the Chilhowee Group. These rocks unconformably overlie basement, or abut basement along steep reverse faults. Rocks of the Chilhowee Group are juxtaposed against Cambrian rocks of the Valley and Ridge province along southeast- and northwest-dipping, high-angle reverse faults. South of the James River (MP 64), Chilhowee Group and basement rocks occupy the hanging wall of the nearly flat-lying Blue Ridge thrust fault and associated splays.South of the Red Valley high-strain zone (MP 144.5), the parkway crosses into the wholly allochthonous eastern Blue Ridge, comprising metasedimentary and meta-igneous rocks assigned to the Wills Ridge, Ashe, and Alligator

Art Rocks with Rock Art!

Science.gov (United States)

Bickett, Marianne

2011-01-01

This article discusses rock art which was the very first "art." Rock art, such as the images created on the stone surfaces of the caves of Lascaux and Altimira, is the true origin of the canvas, paintbrush, and painting media. For there, within caverns deep in the earth, the first artists mixed animal fat, urine, and saliva with powdered minerals…

Serpentinization and fluid-rock interaction in Jurassic mafic and ultramafic sea-floor: constraints from Ligurian ophiolite sequences

Science.gov (United States)

Vogel, Monica; Früh-Green, Gretchen L.; Boschi, Chiara; Schwarzenbach, Esther M.

2014-05-01

The Bracco-Levanto ophiolitic complex (Eastern Liguria) represents one of the largest and better-exposed ophiolitic successions in the Northern Apennines. It is considered to be a fragment of heterogeneous Jurassic lithosphere that records tectono-magmatic and alteration histories similar to those documented along the Mid-Atlantic Ridge, such as at the 15°20'N area and the Atlantis Massif at 30°N. Structural and petrological studies on these rocks provide constraints on metamorphic/deformation processes during formation and hydrothermal alteration of the Jurassic oceanic lithosphere. We present a petrological and geochemical study of deformation processes and fluid-rock interaction in the Bracco-Levanto ophiolitic complex and compare these to modern oceanic hydrothermal systems, such as the Lost City Hydrothermal Field hosted in ultramafic rocks on the Atlantis Massif. A focus is on investigating mass transfer and fluid flow paths during high and low temperature hydrothermal activity, and on processes leading to hydrothermal carbonate precipitation and the formation of ophicalcites, which are characteristic of the Bracco-Levanto sequences. Major element and mineral compositional data allow us to distinguish a multiphase history of alteration characterized by: (1) widespread SiO2 metasomatism during progressive serpentinization, and (2) multiple phases of veining and carbonate precipitation associated with circulation of seawater and high fluid-rock ratios in the shallow ultramafic-dominated portions of the Jurassic seafloor. We observe regional variations in MgO, SiO2 and Al2O3, suggesting Si-flux towards stratigraphically higher units. In general, the ophicalcites have higher Si, Al and Fe concentrations and lower Mg than the serpentinite basement rocks or serpentinites with minimal carbonate veins. Bulk rock trace element data and Sr isotope ratios indicate seawater reacting with rocks of more mafic composition, then channeled towards stratigraphically higher

Electron microscopic study of the myelinated nerve fibres and the perineurial cell basement membrane in the diabetic human peripheral nerves

International Nuclear Information System (INIS)

ElBarrany, Wagih G.; Hamdy, Raid M.; AlHayani, Abdulmonem A.; Jalalah, Sawsan M.

2009-01-01

To study the quantitative and ultrastructural changes in myelinated nerve fibers and the basement membranes of the perineurial cells in diabetic nerves. The study was performed at the Department of Anatomy, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Saudi Arabia from 2003 to 2005. Human sural nerves were obtained from 15 lower limbs and 5 diabetic nerve biopsies. The total mean and density of myelinated nerve fibers per fascicle were calculated, with density of microtubules and mitochondria in the axoplasm. The number of the perineurial cell basement membrane layers was counted, and thickness of the basement membrane was measured. Among the 15 diabetic and 5 normal human sural nerves, the average diameters, number and surface area of myelinated nerve fibers and axonal microtubules density were found to be less in diabetic nerves. Mitochondrial density was higher in diabetic axons. Thickness of the perineurial cell basement membrane had a greater mean, but the number of perineurial cell layers was less than that of the diabetic group. The inner cellular layer of the perineurium of the diabetic nerves contained large vacuoles containing electron-dense degenerated myelin. A few specimens showed degenerated myelinated nerve fibers, while others showed recovering ones. Retracted axoplasms were encountered with albumin extravasation. Diabetes caused an increase in perineurial permeability. The diabetic sural nerve showed marked decrease in the myelinated nerve fibres, increase degenerated mitochondria, and decreased microtubules. (author)

Characterization of 222Rn entry into a basement structure surrounded by low permeability soil

International Nuclear Information System (INIS)

Ward, D.C.

1992-01-01

An experimental facility has been developed to monitor the entry rate and concentration of 222 Rn in two basement type structures surrounded by soil having a permeability on the order of 1- -12 m 2 . A data acquisition system recorded environmental conditions outside and inside the structures, including basement air exchange rates, every 15 min. Indoor 222 Rn concentrations ranged from 400 to 1400 Bq m -3 . The observed 222 Rn entry rate is highly variable and has two primary components; a constant input rate caused by diffusion of 222 Rn through the concrete walls and floor, and a variable rate that depends upon indoor-soil pressure differentials of only a few pascals. Pressure differentials are dependent upon wind speed and wind direction. Stack effect was not significant. During a two week period, with relatively calm winds, diffusion through the concrete walls and floor plus the floor-wall joint accounted for more than 80% of the total 222 Rn entry

Effect of diabetes on in vivo metabolism of [35S]-labeled glomerular basement membrane

International Nuclear Information System (INIS)

Cohen, M.P.; Surma, M.L.

1984-01-01

Glomerular basement membrane (GBM) was labeled in vivo by the injection of tracer amounts of [ 35 S]-sulfate into normal and streptozotocin-diabetic rats. The biosynthesis and turnover of sulfated glycosaminoglycans in the GBM was determined from the specific activity of [ 35 S] after pronase digestion of basement membranes purified from glomeruli isolated 1-7 days after injection. Peak radiolabeling of both normal and diabetic GBM occurred 24 h after injection and, when corrected for differences in serum sulfate specific activities, was less in diabetic than in normal samples. The specific activity of GBM sulfate, expressed as cpm/microgram uronic acid, progressively diminished over the ensuing period of study in both normal and diabetic samples. The rate of decrease in specific activity of [ 35 S]-labeled GBM was not significantly different in diabetic preparations compared with that in normal controls. The findings are compatible with diminished sulfation and/or production but normal turnover of glycosaminoglycans in the renal GBM in experimental diabetes

Evaluation of Fractured Basement Complex Rock Porosity by ...

African Journals Online (AJOL)

current resistivity sounding as complementary geophysical technique to Schlumberger vertical electrical sounding in characterizing fractured geologic systems. Previously, Schlumberger vertical electrical sounding was used to collect data.

Analytical and numerical models for estimating the effect of exhaust ventilation on radon entry in houses with basements or crawl spaces

International Nuclear Information System (INIS)

Mowris, R.J.

1986-08-01

Mechanical exhaust ventilation systems are being installed in newer, energy-efficient houses and their operation can increase the indoor-outdoor pressure differences that drive soil gas and thus radon entry. This thesis presents simplified models for estimating the pressure driven flow of radon into houses with basements or crawl spaces, due to underpressures induced by indoor-outdoor temperature differences, wind, or exhaust ventilation. A two-dimensional finite difference model is presented and used to calculate the pressure field and soil gas flow rate into a basement situated in soil of uniform permeability. A simplified analytical model is compared to the finite difference model with generally very good agreement. Another simplified model is presented for houses with a crawl space. Literature on radon research is also reviewed to show why pressure driven flow of soil gas is considered to be the major source of radon entry in houses with higher-than-average indoor radon concentrations. Comparisons of measured vs. calculated indoor radon concentrations for a house with a basement showed the simplified basement model underpredicting on average by 25%. For a house with a crawl space the simplified crawl space model overpredicted by 23% when the crawl space vents are open and 48% when the crawl space vents are sealed

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

Dynamics of uranium ore formation in the basement and frame of the Streltsovskaya Caldera

International Nuclear Information System (INIS)

Petrov, V.; Schukin, S.

2014-01-01

The analysis of geological-geophysical, paleo-geodynamics, mineralogical, geochemical, isotope, geochronological, and thermo-baro-geochemical data allow us to offer a model of uranium ore formation dynamics in the basement and frame of the Streltsovskaya Caldera connected to activity of the fluid-conducting fault zones network with the aim to identify prospective areas The most ancient fluid-conducting structures are inter-block NE-SW, NNE-submeridional, NW-SE and, probably, WNW-sub-latitudinal faults. The oldest NE-SW faults and schistosity zones were formed during Proterozoic tectonic cycle (TC) with reactivation in T3-J2 time due to global reorganization of stress field and reactivation of tectonic movements. The NNE-submeridional and NW-SE faults were extended with increased fluid permeability during Caledonian and Variscan TCs. They also were reactivated in the process of Late Mesozoic tectonic and magmatic activation (TMA). Thus already at early stages of geotectonic evolution within the intersection of NE-SW (N-Urulyunguyevskiy fault) and NNE-submeridional (Chindachinskaya zone) faults the areas of increased fluid and magmatic activity were formed. The dynamics of fault formation in the basement and frame of the Streltsovskaya caldera and its volcano-sedimentary cover differs. In the basement and granite framework NE-SW, NNEsubmeridional and NW-SE faults are interblock structures of the I rank. Their intersection formed areas of long-term circulation of hydrothermal solutions and telescopic appearance of multi-age metasomatites that created conditions for localizing of vein-stockwork mineralization. In volcanosedimentary cover the NE-SW and NNE-submeridional faults should be considered as interblock structures of the I rank where intersections provided inflow of ore-bearing solutions and their redistribution within the cover. Here the main ore distributing role belongs to NW-SE shears. They are intrablock II rank structures which were formed due to dextral

The Usability of Rock-Like Materials for Numerical Studies on Rocks

Science.gov (United States)

Zengin, Enes; Abiddin Erguler, Zeynal

2017-04-01

The approaches of synthetic rock material and mass are widely used by many researchers for understanding the failure behavior of different rocks. In order to model the failure behavior of rock material, researchers take advantageous of different techniques and software. But, the majority of all these instruments are based on distinct element method (DEM). For modeling the failure behavior of rocks, and so to create a fundamental synthetic rock material model, it is required to perform related laboratory experiments for providing strength parameters. In modelling studies, model calibration processes are performed by using parameters of intact rocks such as porosity, grain size, modulus of elasticity and Poisson ratio. In some cases, it can be difficult or even impossible to acquire representative rock samples for laboratory experiments from heavily jointed rock masses and vuggy rocks. Considering this limitation, in this study, it was aimed to investigate the applicability of rock-like material (e.g. concrete) to understand and model the failure behavior of rock materials having complex inherent structures. For this purpose, concrete samples having a mixture of %65 cement dust and %35 water were utilized. Accordingly, intact concrete samples representing rocks were prepared in laboratory conditions and their physical properties such as porosity, pore size and density etc. were determined. In addition, to acquire the mechanical parameters of concrete samples, uniaxial compressive strength (UCS) tests were also performed by simultaneously measuring strain during testing. The measured physical and mechanical properties of these extracted concrete samples were used to create synthetic material and then uniaxial compressive tests were modeled and performed by using two dimensional discontinuum program known as Particle Flow Code (PFC2D). After modeling studies in PFC2D, approximately similar failure mechanism and testing results were achieved from both experimental and

Experimental autoimmune glomerulonephritis induced by anti-glomerular basement membrane antibody. II. Effects of injecting heterologous, homologous, or autologous glomerular basement membranes and complete Freund's adjuvant into sheep.

OpenAIRE

Steblay, R. W.; Rudofsky, U. H.

1983-01-01

The effects of injecting human, rabbit, rat, or single-kidney homologous glomerular basement membrane (GBM) or autologous GBM, each in complete Freund's adjuvant (CFA), into 15- to 18-month-old sheep are compared. All sheep receiving heterologous GBM and 3 of 6 sheep receiving homologous GBM had anti-GBM nephritis, but such sheep did not bind autoantibodies or have Goodpasturelike lesions in their lungs. Sheep given injections of human GBM had autoantibodies to antigenic determinants shared b...

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

On the lag time between internal strain and basement involved thrust induced exhumation: The case of the Colombian Eastern Cordillera

Science.gov (United States)

Mora, Andrès; Blanco, Vladimir; Naranjo, Julian; Sanchez, Nelson; Ketcham, Richard A.; Rubiano, Jorge; Stockli, Daniel F.; Quintero, Isaid; Nemčok, Michal; Horton, Brian K.; Davila, Hamblet

2013-07-01

Thrust sheets accumulate internal strain before they start moving along discrete fault planes. However, there are no previous studies evaluating the time difference between initiation of strain and fault displacement. In this paper we use observations from the Eastern Cordillera of Colombia to evaluate this interval. We utilize multiple thermochronometers and paleothermometers to refine the timing of deformation. Based on these new data we build time-temperature path estimates that together with geometric outcrop-based structural analysis and fluid inclusions allow us to assign relative timing to features associated with strain, such as cleavage, veins and certain types of fractures, and compare that with the timing of thrusting. We find that cleavage was only formed close to maximum paleotemperatures, almost coeval with the onset of thrust-induced denudation by the Late Oligocene. The corresponding structural level of fold-related veins suggest that they were formed later but still when the country rocks were at temperatures higher than 160 °C, mostly during the Early Miocene and still coexisted with the latest stages of cleavage formation. Our data show that the main period of strain hardening was short (probably a few million years) and occurred before first-order basement thrusting was dominant, but was associated with second-order folding.

The use of Nd isotopes to establish sedimentary provenance at inverted passive margins: The case of Andrelandia depositional cycle at the Riberia belt, Brazil

International Nuclear Information System (INIS)

Ragatky, D.; Tupinamba, M.; Duarte, B.P

2001-01-01

The Ribeira Belt (Almeida et al., 1973), in southeastern Brazil, is a Brasiliano/Pan-African belt that resulted from the agglutination of the Gondwana Supercontinent (750-500 Ma). The tectonic organization at its central segment can be defined by several tectono-stratigraphic domains (Heilbron et al., 1998, 2000). In general terms, each tectonic domain comprises: a) pre-1.8 Ga basement rocks; b) post-1.8 Ga metasedimentary cover including metabasic rocks of continental to MORB geochemical affinity; and c) Brasiliano-Pan African granitoids. U/Pb ages for zircon, titanite and monazite of both the pre-1.8 Ga basement and Brasiliano granitoids (Machado et al., 1996) reveal that basement gneisses were generated during the Transamazonian Orogeny, about 2.1 Ga. Peak metamorphic conditions (M1) of the Brasiliano Collage at the central Ribeira belt were reached at 590 - 565 Ma, with a second metamorphic event (M2) at 535 - 520 Ma (Machado et al., 1996). Our research area is located at the transition between the foreland and the hinterland of the Ribeira belt: the Occidental terrane. It represents a reworked margin of the Sao Francisco Craton, formerly known as a proterozoic tectonic plate. It is composed by two crustal scale thrust sheets (Andrelandia and Juiz de Fora domains) tangentially transported towards the foreland of Sao Francisco Craton. Despite the well-determined ages of the Transamazonic basement and Brasiliano granitic rocks (Machado et al. 1996), the sedimentary source of the siliciclastic cover at the Occidental terrane remains poorly known. In this case, the use of Nd isotopic system, due to its relative immobility, is an important additional tool of investigation in geological correlation between basement source areas and sedimentary cover. The siliciclastic sedimentary and metasedimentary rocks are formed by detritus of pre-existing crustal rocks and they could be formed by more than one source. Then, depleted mantle Nd model ages (T DM ) for sediments

Methods and uncertainty estimations of 3-D structural modelling in crystalline rocks: a case study

Science.gov (United States)

Schneeberger, Raphael; de La Varga, Miguel; Egli, Daniel; Berger, Alfons; Kober, Florian; Wellmann, Florian; Herwegh, Marco

2017-09-01

Exhumed basement rocks are often dissected by faults, the latter controlling physical parameters such as rock strength, porosity, or permeability. Knowledge on the three-dimensional (3-D) geometry of the fault pattern and its continuation with depth is therefore of paramount importance for applied geology projects (e.g. tunnelling, nuclear waste disposal) in crystalline bedrock. The central Aar massif (Central Switzerland) serves as a study area where we investigate the 3-D geometry of the Alpine fault pattern by means of both surface (fieldwork and remote sensing) and underground ground (mapping of the Grimsel Test Site) information. The fault zone pattern consists of planar steep major faults (kilometre scale) interconnected with secondary relay faults (hectometre scale). Starting with surface data, we present a workflow for structural 3-D modelling of the primary faults based on a comparison of three extrapolation approaches based on (a) field data, (b) Delaunay triangulation, and (c) a best-fitting moment of inertia analysis. The quality of these surface-data-based 3-D models is then tested with respect to the fit of the predictions with the underground appearance of faults. All three extrapolation approaches result in a close fit ( > 10 %) when compared with underground rock laboratory mapping. Subsequently, we performed a statistical interpolation based on Bayesian inference in order to validate and further constrain the uncertainty of the extrapolation approaches. This comparison indicates that fieldwork at the surface is key for accurately constraining the geometry of the fault pattern and enabling a proper extrapolation of major faults towards depth. Considerable uncertainties, however, persist with respect to smaller-sized secondary structures because of their limited spatial extensions and unknown reoccurrence intervals.

A study of the influence of a gravel subslab layer on radon entry rate using two basement structures

International Nuclear Information System (INIS)

Robinson, A.L.; Sextro, R.G.; Fisk, W.J.; Garbesi, K.; Wooley, J.; Wollenberg, H.A.

1993-01-01

In buildings with elevated radon concentrations, the dominant transport mechanism of radon is advective flow of soil gas into the building substructure. However, the building-soil system is often complex, making detailed studies of the radon source term difficult. In order to examine radon entry into buildings, the authors have constructed two room-size, precisely-fabricated basement structures at a site with relatively homogeneous, moderately permeable soil. The basements are identical except that one lies directly on native soil whereas the other lies on a high permeability aggregate layer. The soil pressure field and radon entry rate have been measured for different basement pressures and environmental conditions. The subslab gravel layer greatly enhances the advective entry of radon into the structure; when the structures are depressurized, the radon entry rate into the structure with the subslab gravel layer is more than a factor of 3 times the radon entry rate into the other structure for the same depressurization. The gravel subslab layer also spreads the pressure field around the structure, extending the field of influence of the structure and the region from which it draws radon

A study of the influence of a gravel subslab layer on radon entry rate using two basement structures

International Nuclear Information System (INIS)

Robinson, A.L.; Sextro, R.G.; Fisk, W.J.; Garbesi, K.; Wooley, J.; Wollenberg, H.A.

1993-01-01

In buildings with elevated radon concentrations, the dominant transport mechanism of radon is advective flow of soil gas into the building substructure. However, the building-soil system is often complex, making detailed studies of the radon source term difficult. In order-to examine radon entry into buildings, we have constructed two room-size, precisely-fabricated basement structures at a site with relatively homogeneous, moderately permeable soil. The basements are identical except that one lies directly on native soil whereas the other lies on a high permeability aggregate layer. The soil pressure field and radon entry rate have been measured for different basement pressures and environmental conditions. The subslab gravel layer greatly enhances the advective entry of radon into the structure; when the structures are depressurized, the radon entry rate into the structure with the subslab gravel layer is more than a factor of 3 times the radon entry rate into the other structure for the same depressurization. The gravel subslab layer also spreads the pressure field around the structure, extending the field of influence of the structure and the region from which it draws radon. (orig.). (7 refs., 3 figs.)

Immunochemical and ultrastructural assessment of the nature of the pericellular basement membrane of human decidual cells

DEFF Research Database (Denmark)

Wewer, U M; Faber, M; Liotta, L A

1985-01-01

Human decidual cells of early and late pregnancy were studied immunochemically and ultrastructurally with respect to the presence and nature of pericellular basement membrane material. The most prominent cell type in decidual tissue of both early and late pregnancy were large, mature epithelioid......-linked immunosorbent assay. Biosynthesis of laminin was shown by [35S]methionine labeling of short term organ cultures of decidual tissue followed by immunoprecipation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and fluorography. The laminin chains migrated with the apparent molecular weights of 300...... and 200 kilodaltons under reducing conditions. Two other separate populations of cells were apparent in the decidual tissue of early pregnancy. A smaller group of rounded intermediate sized (15 to 25 micron) decidual cells had focal deposits basement membrane immunoreactive material scattered at the cell...

Aluminum-containing dense deposits of the glomerular basement membrane: identification by energy dispersive X-ray analysis

International Nuclear Information System (INIS)

Smith, D.M. Jr.; Pitcock, J.A.; Murphy, W.M.

1982-01-01

Heavy metals, including gold, mercury, lead, bismuth, and cadmium, have the potential to cause renal disease. With the development of X-ray microanalysis, these heavy metals can now be identified in tissue deposits. This report describes a case of renal failure, probably related to dysproteinemia, in which granular, electron-opaque dense deposits were present in the glomerular basement membranes. Energy dispersive X-ray analysis demonstrated that these dense deposits contained aluminum. An analysis of this patient's history in relation to the current knowledge of aluminum metabolism suggests that the aluminum deposition occurred secondary to previous glomerular injury. This case emphasizes the need to utilize heavy metal identification technology whenever granular, electron-opaque dense deposits are identified and represents, to our knowledge, the first study to document aluminum deposits within the glomerular basement membrane of humans

Geology of the uranium deposits related to the sub-Athabasca unconformity, Saskatchewan

International Nuclear Information System (INIS)

Tremblay, L.P.

1982-01-01

The Athabasca Basin is a large, oval, dish-shaped structure, 425 km by 225 km (80 000 km 2 ) containing about 1500 m of mainly flat-lying quartz-rich sandstone of the Athabasca Group. The basin lies with marked angular unconformity across a Hudsonian basement of deformed and metamorphosed Archean and Aphebian sedimentary, volcanic and plutonic rocks trending north to northeast beneath the basin. In the Carswell Circular Structure in the central western half of the basin rocks are brought to surface through 1200 m of sandstone. The rocks of the basin are less than one percent exposed. Overburden locally reaches 90 m thick. Uranium deposits have been found near the southeast edge of the basin, within the Carswell Circular Structure, and along the northern rim of the basin. They are (1) at the unconformity as high-grade masses elongated in and parallel to major faults, hosted mainly in highly-altered white clay feldspar-rich basement rocks and associated with graphitic metasediments and calc-silicate rocks; (2) within the first 40 m above the unconformity in grey to black and multicoloured Athabasca sandstones and shales as a coating on quartz grains, as disseminations in the clay matrix and as veins; and (3) within 100 m below the unconformity as fracture fillings and disseminations in basement rocks

Rock Art

Science.gov (United States)

Henn, Cynthia A.

2004-01-01

There are many interpretations for the symbols that are seen in rock art, but no decoding key has ever been discovered. This article describes one classroom's experiences with a lesson on rock art--making their rock art and developing their own personal symbols. This lesson allowed for creativity, while giving an opportunity for integration…

Radon transport into a detached one-story house with a basement

International Nuclear Information System (INIS)

D'Ottavio, T.W.; Dietz, R.N.; Nazaroff, W.W.; California Institute of Technology

1986-01-01

The interpretation of the data presented in a paper published in 1985 on radon transport into a detached one-story house with a basement is extended by developing an improved model that can be used to predict radon concentration in this house. In particular, emphasis was placed on a more complete set of replotted sump activity data. In the author's reply, this development is welcomed but two concerns regarding the conclusions one might infer from the analysis are discussed. (UK)

System for detecting nuclear explosions

International Nuclear Information System (INIS)

Rawls, L.E.

1978-01-01

Apparatus for detecting underground nuclear explosions is described that is comprised of an antenna located in the dielectric substance of a deep waveguide in the earth and adapted to detect low frequency electromagnetic waves generated by a nuclear explosion, the deep waveguide comprising the high conductivity upper sedimentary layers of the earth, the dielectric basement rock, and a high conductivity layer of basement rock due to the increased temperature thereof at great depths, and means for receiving the electromagnetic waves detected by said antenna means

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.

Thermally induced rock stress increment and rock reinforcement response

International Nuclear Information System (INIS)

Hakala, M.; Stroem, J.; Nujiten, G.; Uotinen, L.; Siren, T.; Suikkanen, J.

2014-07-01

This report describes a detailed study of the effect of thermal heating by the spent nuclear fuel containers on the in situ rock stress, any potential rock failure, and associated rock reinforcement strategies for the Olkiluoto underground repository. The modelling approach and input data are presented together repository layout diagrams. The numerical codes used to establish the effects of heating on the in situ stress field are outlined, together with the rock mass parameters, in situ stress values, radiogenic temperatures and reinforcement structures. This is followed by a study of the temperature and stress evolution during the repository's operational period and the effect of the heating on the reinforcement structures. It is found that, during excavation, the maximum principal stress is concentrated at the transition areas where the profile changes and that, due to the heating from the deposition of spent nuclear fuel, the maximum principal stress rises significantly in the tunnel arch area of NW/SW oriented central tunnels. However, it is predicted that the rock's crack damage (CD, short term strength) value of 99 MPa will not be exceeded anywhere within the model. Loads onto the reinforcement structures will come from damaged and loosened rock which is assumed in the modelling as a free rock wedge - but this is very much a worst case scenario because there is no guarantee that rock cracking would form a free rock block. The structural capacity of the reinforcement structures is described and it is predicted that the current quantity of the rock reinforcement is strong enough to provide a stable tunnel opening during the peak of the long term stress state, with damage predicted on the sprayed concrete liner. However, the long term stability and safety can be improved through the implementation of the principles of the Observational Method. The effect of ventilation is also considered and an additional study of the radiogenic heating effect on the brittle

Thermally induced rock stress increment and rock reinforcement response

Energy Technology Data Exchange (ETDEWEB)

Hakala, M. [KMS Hakala Oy, Nokia (Finland); Stroem, J.; Nujiten, G.; Uotinen, L. [Rockplan, Helsinki (Finland); Siren, T.; Suikkanen, J.

2014-07-15

This report describes a detailed study of the effect of thermal heating by the spent nuclear fuel containers on the in situ rock stress, any potential rock failure, and associated rock reinforcement strategies for the Olkiluoto underground repository. The modelling approach and input data are presented together repository layout diagrams. The numerical codes used to establish the effects of heating on the in situ stress field are outlined, together with the rock mass parameters, in situ stress values, radiogenic temperatures and reinforcement structures. This is followed by a study of the temperature and stress evolution during the repository's operational period and the effect of the heating on the reinforcement structures. It is found that, during excavation, the maximum principal stress is concentrated at the transition areas where the profile changes and that, due to the heating from the deposition of spent nuclear fuel, the maximum principal stress rises significantly in the tunnel arch area of NW/SW oriented central tunnels. However, it is predicted that the rock's crack damage (CD, short term strength) value of 99 MPa will not be exceeded anywhere within the model. Loads onto the reinforcement structures will come from damaged and loosened rock which is assumed in the modelling as a free rock wedge - but this is very much a worst case scenario because there is no guarantee that rock cracking would form a free rock block. The structural capacity of the reinforcement structures is described and it is predicted that the current quantity of the rock reinforcement is strong enough to provide a stable tunnel opening during the peak of the long term stress state, with damage predicted on the sprayed concrete liner. However, the long term stability and safety can be improved through the implementation of the principles of the Observational Method. The effect of ventilation is also considered and an additional study of the radiogenic heating effect on the

Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

Science.gov (United States)

Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

2006-01-01

High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

Comparison of disposal concepts for rock salt and hard rock

International Nuclear Information System (INIS)

Papp, R.

1998-01-01

The study was carried out in the period 1994-1996. The goals were to prepare a draft on spent fuel disposal in hard rock and additionally a comparison with existing disposal concepts for rock salt. A cask for direct disposal of spent fuel and a repository for hard rock including a safeguards concept were conceptually designed. The results of the study confirm, that the early German decision to employ rock salt was reasonable. (orig.)

Provenance and tectonic setting of the Neoproterozoic clastic rocks hosting the Banana Zone Cu-Ag mineralisation, northwest Botswana

Science.gov (United States)

Kelepile, Tebogo; Bineli Betsi, Thierry; Franchi, Fulvio; Shemang, Elisha; Suh, Cheo Emmanuel

2017-05-01

Petrographic and geochemical data were combined in order to decipher the petrogenesis of the Neoproterozoic sedimentary succession associated with the Banana Zone Cu-Ag mineralisation (northwest Botswana), in the Kalahari Copperbelt. The investigated Neoproterozoic sedimentary succession is composed of two formations including the Ngwako Pan and the D'kar Formations. The Ngwako Pan Formation is made up of continental siliciclastic sediments, mainly sandstones interbedded with siltstones and mudstones, whereas the D'kar Formation is comprised of shallow marine laminated siltstones, sandstones and mudstones, with subordinate limestone. Copper-Ag mineralisation is essentially confined at the base of the D'kar Formation, which bears reduced organic components, likely to have controlled Cu-Ag precipitation. Sandstones of both the Ngwako Pan and the D'kar Formations are arkoses and subarkoses, composed of quartz (Q), feldspars (F) and lithic fragments (L). Moreover, geochemically the sandstones are considered as potassic and classified as arkoses. On the other hand, mudrocks of the D'kar Formation are finely laminated and are dominated by muscovite, sericite, chlorite and quartz. The modified chemical index of weathering (CIW‧) values indicated an intense chemical weathering of the source rock. The dominance of detrital quartz and feldspar grains coupled with Al2O3/TiO2 ratios (average 29.67 and 24.52 for Ngwako Pan and D'kar Formations, respectively) and Ni and Cr depletion in the sandstones, suggest a dominant felsic source. However, high concentrations of Ni and Cr and a low Al2O3/TiO2 ratio (block and deposited in a continental rift setting (passive margin) in a humid environment. The source rocks might have been the Palaeoproterozoic basement rocks (granitoids and granitic gneiss) and the Mesoproterozoic Kgwebe volcanic rocks exposed north of the study area.

Structural heritage, reactivation and distribution of fault and fracture network in a rifting context: Case study of the western shoulder of the Upper Rhine Graben

Science.gov (United States)

Bertrand, Lionel; Jusseaume, Jessie; Géraud, Yves; Diraison, Marc; Damy, Pierre-Clément; Navelot, Vivien; Haffen, Sébastien

2018-03-01

In fractured reservoirs in the basement of extensional basins, fault and fracture parameters like density, spacing and length distribution are key properties for modelling and prediction of reservoir properties and fluids flow. As only large faults are detectable using basin-scale geophysical investigations, these fine-scale parameters need to be inferred from faults and fractures in analogous rocks at the outcrop. In this study, we use the western shoulder of the Upper Rhine Graben as an outcropping analogue of several deep borehole projects in the basement of the graben. Geological regional data, DTM (Digital Terrain Model) mapping and outcrop studies with scanlines are used to determine the spatial arrangement of the faults from the regional to the reservoir scale. The data shows that: 1) The fault network can be hierarchized in three different orders of scale and structural blocks with a characteristic structuration. This is consistent with other basement rocks studies in other rifting system allowing the extrapolation of the important parameters for modelling. 2) In the structural blocks, the fracture network linked to the faults is linked to the interplay between rock facies variation linked to the rock emplacement and the rifting event.

Mechanism of Rock Burst Occurrence in Specially Thick Coal Seam with Rock Parting

Science.gov (United States)

Wang, Jian-chao; Jiang, Fu-xing; Meng, Xiang-jun; Wang, Xu-you; Zhu, Si-tao; Feng, Yu

2016-05-01

Specially thick coal seam with complex construction, such as rock parting and alternative soft and hard coal, is called specially thick coal seam with rock parting (STCSRP), which easily leads to rock burst during mining. Based on the stress distribution of rock parting zone, this study investigated the mechanism, engineering discriminant conditions, prevention methods, and risk evaluation method of rock burst occurrence in STCSRP through setting up a mechanical model. The main conclusions of this study are as follows. (1) When the mining face moves closer to the rock parting zone, the original non-uniform stress of the rock parting zone and the advancing stress of the mining face are combined to intensify gradually the shearing action of coal near the mining face. When the shearing action reaches a certain degree, rock burst easily occurs near the mining face. (2) Rock burst occurrence in STCSRP is positively associated with mining depth, advancing stress concentration factor of the mining face, thickness of rock parting, bursting liability of coal, thickness ratio of rock parting to coal seam, and difference of elastic modulus between rock parting and coal, whereas negatively associated with shear strength. (3) Technologies of large-diameter drilling, coal seam water injection, and deep hole blasting can reduce advancing stress concentration factor, thickness of rock parting, and difference of elastic modulus between rock parting and coal to lower the risk of rock burst in STCSRP. (4) The research result was applied to evaluate and control the risk of rock burst occurrence in STCSRP.

Rollerjaw Rock Crusher

Science.gov (United States)

Peters, Gregory; Brown, Kyle; Fuerstenau, Stephen

2009-01-01

The rollerjaw rock crusher melds the concepts of jaw crushing and roll crushing long employed in the mining and rock-crushing industries. Rollerjaw rock crushers have been proposed for inclusion in geological exploration missions on Mars, where they would be used to pulverize rock samples into powders in the tens of micrometer particle size range required for analysis by scientific instruments.

Convective influx/glymphatic system: tracers injected into the CSF enter and leave the brain along separate periarterial basement membrane pathways.

Science.gov (United States)

Albargothy, Nazira J; Johnston, David A; MacGregor-Sharp, Matthew; Weller, Roy O; Verma, Ajay; Hawkes, Cheryl A; Carare, Roxana O

2018-05-12

Tracers injected into CSF pass into the brain alongside arteries and out again. This has been recently termed the "glymphatic system" that proposes tracers enter the brain along periarterial "spaces" and leave the brain along the walls of veins. The object of the present study is to test the hypothesis that: (1) tracers from the CSF enter the cerebral cortex along pial-glial basement membranes as there are no perivascular "spaces" around cortical arteries, (2) tracers leave the brain along smooth muscle cell basement membranes that form the Intramural Peri-Arterial Drainage (IPAD) pathways for the elimination of interstitial fluid and solutes from the brain. 2 μL of 100 μM soluble, fluorescent fixable amyloid β (Aβ) were injected into the CSF of the cisterna magna of 6-10 and 24-30 month-old male mice and their brains were examined 5 and 30 min later. At 5 min, immunocytochemistry and confocal microscopy revealed Aβ on the outer aspects of cortical arteries colocalized with α-2 laminin in the pial-glial basement membranes. At 30 min, Aβ was colocalised with collagen IV in smooth muscle cell basement membranes in the walls of cortical arteries corresponding to the IPAD pathways. No evidence for drainage along the walls of veins was found. Measurements of the depth of penetration of tracer were taken from 11 regions of the brain. Maximum depths of penetration of tracer into the brain were achieved in the pons and caudoputamen. Conclusions drawn from the present study are that tracers injected into the CSF enter and leave the brain along separate periarterial basement membrane pathways. The exit route is along IPAD pathways in which Aβ accumulates in cerebral amyloid angiopathy (CAA) in Alzheimer's disease. Results from this study suggest that CSF may be a suitable route for delivery of therapies for neurological diseases, including CAA.

Range sections as rock models for intensity rock scene segmentation

CSIR Research Space (South Africa)

Mkwelo, S

2007-11-01

Full Text Available This paper presents another approach to segmenting a scene of rocks on a conveyor belt for the purposes of measuring rock size. Rock size estimation instruments are used to monitor, optimize and control milling and crushing in the mining industry...

A reworked Lake Zone margin: Chronological and geochemical constraints from the Ordovician arc-related basement of the Hovd Zone (western Mongolia)

Science.gov (United States)

Soejono, Igor; Buriánek, David; Janoušek, Vojtěch; Svojtka, Martin; Čáp, Pavel; Erban, Vojtěch; Ganpurev, Nyamtsetseg

2017-12-01

The primary relationships and character of the boundaries between principal lithotectonic domains in the Mongolian tract of the Central Asian Orogenic Belt (CAOB) are still poorly constrained. This brings much uncertainty in understanding of the orogeny configuration and the complete accretionary history. The plutonic Khuurai Tsenkher Gol Complex and the mainly metasedimentary Bij Group represent associated medium- to high-grade basement complexes exposed in the Hovd Zone close to its boundary with the Lake Zone in western Mongolia. The Khuurai Tsenkher Gol Complex is composed of variously deformed acid to basic magmatic rocks intimately associated with the metamorphosed sedimentary and volcanic rocks of the Bij Group. Results of our field work, new U-Pb zircon ages and whole-rock geochemical data suggest an existence of two separate magmatic events within the evolution of the Khuurai Tsenkher Gol Complex. Early to Mid-Ordovician (476 ± 5 Ma and 467 ± 4 Ma protoliths) normal- to high-K calc-alkaline orthogneisses, metadiorites and metagabbros predominate over Mid-Silurian (430 ± 3 Ma) tholeiitic-mildly alkaline quartz monzodiorites. Whereas the geochemical signature of the former suite unequivocally demonstrates its magmatic-arc origin, that of the latter quartz monzodiorite suggests an intra-plate setting. As shown by Sr-Nd isotopic data, the older arc-related magmas were derived from depleted mantle and/or were generated by partial melting of juvenile metabasic crust. Detrital zircon age populations of the metasedimentary rocks together with geochemical signatures of the associated amphibolites imply that the Bij Group was a volcano-sedimentary sequence, formed probably in the associated fore-arc wedge basin. Moreover, our data argue for an identical provenance of the Altai and Hovd domains, overall westward sediment transport during the Early Palaeozoic and the east-dipping subduction polarity. The obvious similarities of the Khuurai Tsenkher Gol Complex

Perlecan (basement membrane heparan sulfate proteoglycan and its role in oral malignancies: An overview

Directory of Open Access Journals (Sweden)

Mithilesh Mishra

2011-01-01

Full Text Available Perlecan means pearl-like structures. Perlecan is a large proteoglycan (400-500 kDa present in virtually all vascularized tissues with a distribution that is primarily confined to basement membranes including those of oral mucosa. It is a basement membrane-type heparan sulfate proteoglycan. Perlecan is synthesized by basal cells and fibroblasts adjacent to the basal lamina . Perlecan is also synthesized by vascular endothelial and smooth muscle cells present in the extracellular matrix. It has been demonstrated in recent years that perlecan is distributed in the stromal space of various pathophysiological conditions. The complex pleiotropy of perlecan suggests that this gene product is involved in several developmental processes, at both early and late stages of embryogenesis, as well as in cancer and diabetes. In the oral cavity, perlecan expression is reported to basal cells in normal mucosa and its expression increases in precancer and cancerous conditions. It is also expressed in various odontogenic tumors such as ameloblastoma, keratocyst odontogenic tumor, and also salivary gland tumors such as adenoid cystic carcinoma, mucoepidermoid carcinoma, etc.

A method for evaluating basement exhumation histories from closure age distributions of detrital minerals

International Nuclear Information System (INIS)

Lovera, Oscar M.; Grove, Marty; Kimbrough, David L.; Abbott, Patrick L.

1999-01-01

We have developed a two-dimensional, thermokinetic model that predicts the closure age distributions of detrital minerals from pervasively intruded and differentially exhumed basement. Using this model, we outline a method to determine the denudation history of orogenic regions on the basis of closure age distributions in synorogenic to postorogenic forearc strata. At relatively high mean denudation rates of 0.5 km m.y.-1 sustained over millions of years, magmatic heating events have minimal influence upon the age distributions of detrital minerals such as K-feldspar that are moderately retentive of radiogenic Ar. At lower rates, however, the effects of batholith emplacement may be substantial. We have applied the approach to detrital K-feldspars from forearc strata derived from the deeply denuded Peninsular Ranges batholith (PRB). Agreement of the denudation history deduced from the detrital K-feldspar data with thermochronologic constraints from exposed PRB basement lead us to conclude that exhumation histories of magmatic arcs should be decipherable solely from closure age distributions of detrital minerals whose depositional age is known. (c) 1999 American Geophysical Union

Raetrad model extensions for radon entry into multi-level buildings with basements or crawl spaces.

Science.gov (United States)

Nielson, K K; Rogers, V C; Rogers, V; Holt, R B

1997-10-01

The RAETRAD model was generalized to characterize radon generation and movement from soils and building materials into multi-level buildings with basements or crawl spaces. With the generalization, the model retains its original simplicity and ease of use. The model calculates radon entry rates that are consistent with measurements published for basement test structures at Colorado State University, confirming approximately equal contributions from diffusion and pressure-driven air flow at indoor-outdoor air pressure differences of deltaP(i-o) = -3.5 Pa. About one-fourth of the diffusive radon entry comes from concrete slabs and three-fourths comes from the surrounding soils. Calculated radon entry rates with and without a barrier over floor-wall shrinkage cracks generally agree with Colorado State University measurements when a sustained pressure of deltaP(i-o) = -2 Pa is used to represent calm wind (<1 m s(-1)) conditions. Calculated radon distributions in a 2-level house also are consistent with published measurements and equations.

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)

Physical properties of sidewall cores from Decatur, Illinois

Science.gov (United States)

Morrow, Carolyn A.; Kaven, Joern; Moore, Diane E.; Lockner, David A.

2017-10-18

To better assess the reservoir conditions influencing the induced seismicity hazard near a carbon dioxide sequestration demonstration site in Decatur, Ill., core samples from three deep drill holes were tested to determine a suite of physical properties including bulk density, porosity, permeability, Young’s modulus, Poisson’s ratio, and failure strength. Representative samples of the shale cap rock, the sandstone reservoir, and the Precambrian basement were selected for comparison. Physical properties were strongly dependent on lithology. Bulk density was inversely related to porosity, with the cap rock and basement samples being both least porous (

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

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

Basement membranes contain several proteoglycans, and those bearing heparan sulfate glycosaminoglycans such as perlecan and agrin usually predominate. Most mammalian basement membranes also contain chondroitin sulfate, and a core protein, bamacan, has been partially characterized. We have now....... 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...

Expression and deposition of basement membrane proteins by brain capillary endothelial cells in a primary murine model of the blood-brain barrier

DEFF Research Database (Denmark)

Thomsen, Maj Schneider; Birkelund, Svend; Larsen, Annette Burkhart

2016-01-01

The blood-brain barrier (BBB) represents the interface between the blood and the brain parenchyma and consists of endothelial cells which are tightly sealed together by tight junction proteins. The endothelial cells are in addition supported by pericytes, which are embedded in the vascular basement...... of the present study was to create four different in vitro constructs of the murine BBB to characterise if the expression and secretion of basement membrane proteins by the murine brain capillary endothelial cells (mBCECs) was affected by co-culturing with pericytes, mixed glial cells, or both. Primary m......BCECs and pericytes were isolated from brains of adult mice. Mixed glial cells were prepared from cerebral cortices of newborn mice. The mBCECs were grown as mono-culture, or co-cultured with pericytes, mixed glial cells, or both. To study the expression of basement membrane proteins RT-qPCR, mass spectrometry...

Synthesis and deposition of basement membrane proteins by primary brain capillary endothelial cells in a murine model of the blood-brain barrier.

Science.gov (United States)

Thomsen, Maj Schneider; Birkelund, Svend; Burkhart, Annette; Stensballe, Allan; Moos, Torben

2017-03-01

The brain vascular basement membrane is important for both blood-brain barrier (BBB) development, stability, and barrier integrity and the contribution hereto from brain capillary endothelial cells (BCECs), pericytes, and astrocytes of the BBB is probably significant. The aim of this study was to analyse four different in vitro models of the murine BBB for expression and possible secretion of major basement membrane proteins from murine BCECs (mBCECs). mBCECs, pericytes and glial cells (mainly astrocytes and microglia) were prepared from brains of C57BL/6 mice. The mBCECs were grown as monoculture, in co-culture with pericytes or mixed glial cells, or as a triple-culture with both pericytes and mixed glial cells. The integrity of the BBB models was validated by measures of transendothelial electrical resistance (TEER) and passive permeability to mannitol. The expression of basement membrane proteins was analysed using RT-qPCR, mass spectrometry and immunocytochemistry. Co-culturing mBCECs with pericytes, mixed glial cells, or both significantly increased the TEER compared to the monoculture, and a low passive permeability was correlated with high TEER. The mBCECs expressed all major basement membrane proteins such as laminin-411, laminin-511, collagen [α1(IV)] 2 α2(IV), agrin, perlecan, and nidogen 1 and 2 in vitro. Increased expression of the laminin α5 subunit correlated with the addition of BBB-inducing factors (hydrocortisone, Ro 20-1724, and pCPT-cAMP), whereas increased expression of collagen IV α1 primarily correlated with increased levels of cAMP. In conclusion, BCECs cultured in vitro coherently form a BBB and express basement membrane proteins as a feature of maturation. Cover Image for this issue: doi: 10.1111/jnc.13789. © 2016 International Society for Neurochemistry.

WHERE DO THE ALPS' FOOTHILLS END? THE DEPTHS OF THE PRE-CENOZOIC BASEMENT IN THE FOREGROUND OF VAS-HEGY– ALPOKALJA, WESTERN HUNGARY

Directory of Open Access Journals (Sweden)

SZÉKELY BALÁZS

2013-11-01

Full Text Available In the past three decades numerous researches have been published containing maps describing basement morphology. The first basement interpretations were based on the correlation of borehole data, then in the ’80s further seismic surveys offered the possibility to refine the outcomes. We collected and compared these data – by following a geoinformatical approach - and integrated them during the preparation stage of the measurement obtained in the 2012 field trip of Eötvös Loránd University, Department of Geophysics and Space Science. By summing up all the data we are able to create a more accurate Pre-Cenozioc basemap of the studied area. The map covers approx. 300 km2 area in the west of Hungary, between the national border and Szombathely, in the eastern foreground of Vas-hegy. We compared five basemaps (KILENYI & RUMPLER 1984, FLÜGEL 1988, KILÉNYI & ŠEFARA 1989, DANK & FÜLÖP 1990, HASS et al. 2010, two magnetic (HOFFER 1960, FANCSIK et al. 2006, a Bouguer-anomaly map (FANCSIK et al. 2005 and torsion balance anomaly map (VAJK 1938. Apparently, by this comparison we can see that the depth of Pre-Cenozoic basement is interpreted in different ways in each article. In contradictory and information deficient areas an attempt was made to produce supplement data with seismic and magnetic measurements. Eventually, a refined Pre-Cenozoic basemap of the area has been created with the help of our complementing measurements, the old maps and more than twenty boreholes reaching basement. Our results revealed an eastern foothill buried under the surface, although the saddle morphology is unlikely. The model contains a basement with fairly steady slope based on industrial sesmic surveys, our results doubt its hole-like feature.

Dwellings with cellars and basements. A BRE guide to radon remedial measures in existing dwellings

International Nuclear Information System (INIS)

Scivyer, C.R.; Jaggs, M.P.R.

1998-01-01

This guide is one of a series giving practical advice on methods of reducing radon levels in existing dwellings. It is intended to help surveyors, builders and householders who are trying to reduce indoor radon levels in houses with cellars or basements. The guide is based on a large body of remedial work carried out to advice given by BRE, and on discussions with others working in the field. The measures it describes are applicable, in principle, to all dwellings and other buildings of a similar scale and construction which have cellars or basements. Contact details of other organisations referred to are listed at the back of this guide. Basements and cellars are relatively uncommon in the United Kingdom, but where they do occur they are likely to be major contributors to the radon problem within a building. Experience shows that most houses with high indoor radon levels can be remedied through the use of straightforward building works. These can be carried out by a builder or householder competent in DIY. The cost should not be excessive. Before reading this guide, for background information on radon, consult Radon: a householder's guide and Radon: a guide to reducing levels M your home, obtainable from local Environmental Health Officers or from the Department of the Environment, Transport and the Regions. The Government recommends that, if the average radon concentration in a dwelling exceeds 200 Bq/m 3 (the 'action' level), measures should be taken to reduce it. This guide assumes that radon measurements have been made in the building and that the annual average indoor radon level was shown to exceed the action level

Modeling and Inversion of Magnetic Anomalies Caused by Sediment–Basement Interface Using Three-Dimensional Cauchy-Type Integrals

DEFF Research Database (Denmark)

Cai, Hongzhu; Zhdanov, Michael

2014-01-01

This letter introduces a new method for the modeling and inversion of magnetic anomalies caused by crystalline basements. The method is based on the 3-D Cauchy-type integral representation of the magnetic field. Traditional methods use volume integrals over the domains occupied by anomalous...... is particularly significant in solving problems of the modeling and inversion of magnetic data for the depth to the basement. In this letter, a novel method is proposed, which only requires discretizing the magnetic contrast surface for modeling and inversion. We demonstrate the method using several synthetic...... susceptibility and on the prismatic representation of the volumes with an anomalous susceptibility distribution. Such discretization is computationally expensive, particularly in 3-D cases. The technique of Cauchy-type integrals makes it possible to represent the magnetic field as surface integrals, which...

Fluid and rock interaction in permeable volcanic rock

International Nuclear Information System (INIS)

Lindley, J.I.

1985-01-01

Four types of interrelated changes -geochemical, mineralogic, isotopic, and physical - occur in Oligocene volcanic units of the Mogollon-Datil volcanic field, New Mexico. These changes resulted from the operation of a geothermal system that, through fluid-rock interaction, affected 5 rhyolite ash-flow tuffs and an intercalated basaltic andesite lava flow causing a potassium metasomatism type of alteration. (1) Previous studies have shown enrichment of rocks in K 2 O as much as 130% of their original values at the expense of Na 2 O and CaO with an accompanying increase in Rb and decreases in MgO and Sr. (2) X-ray diffraction results of this study show that phenocrystic plagioclase and groundmass feldspar have been replaced with pure potassium feldspar and quartz in altered rock. Phenocrystic potassium feldspar, biotite, and quartz are unaffected. Pyroxene in basaltic andesite is replaced by iron oxide. (3) delta 18 O increases for rhyolitic units from values of 8-10 permil, typical of unaltered rock, to 13-15 permil, typical of altered rock. Basaltic andesite, however, shows opposite behavior with a delta 18 of 9 permil in unaltered rock and 6 permit in altered. (4) Alteration results in a density decrease. SEM revealed that replacement of plagioclase by fine-grained quartz and potassium feldspar is not a volume for volume replacement. Secondary porosity is created in the volcanics by the chaotic arrangement of secondary crystals

Lithology of the Late Valdaian glacial moraine in the western part of the Kola Peninsula

Directory of Open Access Journals (Sweden)

Yevzerov V. Ya.

2017-03-01

Full Text Available A profound study of the moraine has been provided. The results have been grouped according to the basement rocks composition. The basal moraines bedding on disintegration products of crystalline rocks, sandy siltstone sediments in the area of abundant metamorphosed and igneous rocks, and on clays in the sandstones occurrence of the Terskaya Suite have been considered. It has been defined that in the basement of the moraine bed there is a clear dependence of the large detrial material composition and the granular composition of the moraine silt on the basement rocks composition. The dependence considerably weakens upwards the section. The received data testify to the plastic glacier flow having dominated in the region, when layers in the glacier basement shifted slowest and the speed of the glacier movement increased upwards the section. The plastic flow has been associated with shifting along internal splits, which provides the inflow of the detrial material to the upper layers of the glacier. Some faults of the moraine that formed under the Middle Dryas advance of the glacier are considered as erratic mass of sedimentary rocks. Their contemporary appearance formed during the change of the glacier gliding along the bed for its inner shifting along internal splits and by plastic flow. An irregularstructured moraine occurred, when the detrial material in flakes, which lost their plasticity and as a result peeled off the basement of the moving glacier, did not consolidate before each flake peeled off. When the interval between the exfoliation of flakes was longer, the transferred detrial material interacted with the formed moraine. In result of the debris abrasion fine layers enriched by clayey particles occurred. The layers can be observed in a moraine with a bedded structure. The tabular structure was produced under the freezing of the previously deposited moraine. The ablation moraine differs from the basal one in its lower silt content. Along

Pan-African deformations in the basement of the Negele area, southern Ethiopia

Science.gov (United States)

Yihunie, Tadesse

2002-03-01

Polydeformed and metamorphosed Neoproterozoic rocks of the East African Orogen in the Negele area constituted three lithostructurally distinct and thrust-bounded terranes. These are, from west to east, the Kenticha, Alghe and Bulbul terranes. The Kenticha and Bulbul terranes are metavolcano-sedimentary and ultramafic sequences, representing parts of the Arabian-Nubian Shield (ANS), which are welded to the central Alghe gneissic terrane of the Mozambique Belt affinity along N-S-trending sheared thrust contacts. Structural data suggest that the Negele basement had evolved through three phases of deformation. During D1 (folding) deformation, north-south upright and inclined folds with north-trending axes were developed. East and west-verging thrusts, right-lateral shearing along the north-oriented Kenticha and Bulbul thrust contacts and related structural elements were developed during D2 (thrusting) deformation. The pervasive D1 event is interpreted to have occurred at 620-610 Ma and the D2 event ended prior to 554 Ma. Right-lateral strike-slips along thrust contacts are interpreted to have been initiated during late D2. During D3, left-lateral strike-slip along the Wadera Shear Zone and respective strike-slip movements along conjugate set of shear zones were developed in the Alghe terrane, and are interpreted to have occurred later than 557 Ma. The structural data suggest that eastward thrusting of the Kenticha and westward tectonic transport of the Bulbul sequences over the Alghe gneissic terrane of the Mozambique Belt, during D2, were accompanied by right-lateral strike-slip displacements along thrust contacts. Right-lateral strike-slip movements along the Kenticha thrust contact, further suggest northward movement of the Kenticha sequence during the Pan-African orogeny in the Neoproterozoic. Left-lateral strike-slip along the orogen-parallel NNE-SSW Wadera Shear Zone and strike-slip movements along a conjugate set of shear zones completed final terrane

Deposition of nucleosomal antigens (histones and DNA) in the epidermal basement membrane in human lupus nephritis.

NARCIS (Netherlands)

Grootscholten, C.; Bruggen, M.C.J. van; Pijl, J.W. van der; Jong, E.M.G.J. de; Ligtenberg, G.; Derksen, R.H.W.M.; Berden, J.H.M.

2003-01-01

OBJECTIVE: Antinuclear autoantibodies complexed to nucleosomes can bind to heparan sulfate (HS) in the glomerular basement membrane. This binding is due to the binding of the positively charged histones to the strongly anionic HS. Nucleosomes and histones have been identified in glomerular deposits

Study of the relationship between mononuclear inflammatory infiltrate and Ki-67 and basement membrane and extracellular matrix protein expression in radicular cysts.

Science.gov (United States)

Mourão, R V C; Júnior, E C Pinheiro; Barros Silva, P G; Turatti, E; Mota, M R L; Alves, A P N N

2016-05-01

To evaluate the relationship between mononuclear inflammatory infiltrate and the expression of a proliferative immunomarker (Ki-67) as well as to evaluate basement membrane and extracellular matrix proteins (laminin and collagen type IV) in radicular cysts and dentigerous cysts (DC). Immunohistochemical analyses were performed in heavily inflamed radicular cysts (HIRC), slightly inflamed radicular cysts (SIRC) and DC (n = 20) using Ki-67 (Dako(®) , 1 : 50), anticollagen type IV (DBS(®) , 1 : 40) and antilaminin (DBS(®) , 1 : 20). The data were analysed using anova/Tukey's test (Ki-67) and Kruskal-Wallis/Dunn's test (collagen type IV and laminin) (P collagen type IV in the basement membrane of the SIRC group was significantly more continuous (P = 0.0475) than in the HIRC group. DC had significantly less collagen type IV in extracellular matrix immunoexpression than HIRC and SIRC (P = 0.0246). Laminin was absent in the basement membrane in the SIRC and DC groups, and the extracellular matrix of the HIRC was weak and punctate. The presence of inflammatory factors in the radicular cyst wall modified the expression of proliferation factors in the epithelial lining and the expression of collagen type IV and laminin in the basement membrane, but did not modify extracellular matrix behaviour in radicular cysts. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Methods and uncertainty estimations of 3-D structural modelling in crystalline rocks: a case study

Directory of Open Access Journals (Sweden)

R. Schneeberger

2017-09-01

Full Text Available Exhumed basement rocks are often dissected by faults, the latter controlling physical parameters such as rock strength, porosity, or permeability. Knowledge on the three-dimensional (3-D geometry of the fault pattern and its continuation with depth is therefore of paramount importance for applied geology projects (e.g. tunnelling, nuclear waste disposal in crystalline bedrock. The central Aar massif (Central Switzerland serves as a study area where we investigate the 3-D geometry of the Alpine fault pattern by means of both surface (fieldwork and remote sensing and underground ground (mapping of the Grimsel Test Site information. The fault zone pattern consists of planar steep major faults (kilometre scale interconnected with secondary relay faults (hectometre scale. Starting with surface data, we present a workflow for structural 3-D modelling of the primary faults based on a comparison of three extrapolation approaches based on (a field data, (b Delaunay triangulation, and (c a best-fitting moment of inertia analysis. The quality of these surface-data-based 3-D models is then tested with respect to the fit of the predictions with the underground appearance of faults. All three extrapolation approaches result in a close fit (> 10 % when compared with underground rock laboratory mapping. Subsequently, we performed a statistical interpolation based on Bayesian inference in order to validate and further constrain the uncertainty of the extrapolation approaches. This comparison indicates that fieldwork at the surface is key for accurately constraining the geometry of the fault pattern and enabling a proper extrapolation of major faults towards depth. Considerable uncertainties, however, persist with respect to smaller-sized secondary structures because of their limited spatial extensions and unknown reoccurrence intervals.

The chest X-ray in antiglomerular basement membrane antibody disease (Goodpasture's syndrome)

International Nuclear Information System (INIS)

Bowley, N.B.; Steiner, R.E.; Chin, W.S.

1979-01-01

The chest radiographs of 25 patients with proven antiglomerular basement membrane antibody disease (Goodpasture's syndrome) were analysed. All except two of the patients had pulmonary haemorrhage at some stage of their disease. Altogether there were 39 episodes of pulmonary haemorrhage, 25 being relapses. During seven episodes the chest radiograph was normal. Relapses of pulmonary haemorrhage never occurred in isolation but were usually associated with infection (not necessarily a chest infection) or occasionally fluid overload. Conversely fluid overload or infection were always associated with pulmonary haemorrhage provided there were high or rising titres of circulating antibodies at the time. Therefore in a patient with antiglomerular basement membrane antibody disease, the presence of shadowing in the lung fields on the chest radiograph almost invariably means the patient has pulmonary haemorrhage whether or not pulmonary oedema or a chest infection are present. Limitation of shadowing by a fissure, loss of major portions of the diaphragmatic or cardiac silhouette, involvement of the lung apex or costophrenic angles suggest an underlying chest infection. Septal lines suggest fluid overload. Pleural effusions are seen with chest infections and fluid overload. The carbon monoxide uptake (KCO) was invariably high in the presence of pulmonary haemorrhage even if the chest radiograph was normal. A combined use of KCO and chest radiographs is the best method of monitoring lung disease in these patients. (author)

Crustal basement controls granitoid magmatism, and implications for generation of continental crust in subduction zones: A Sr-Nd-Hf-O isotopic study from the Paleozoic Tongbai orogen, central China

Science.gov (United States)

Wang, Hao; Wu, Yuan-Bao; Yang, Jin-Hui; Qin, Zheng-Wei; Duan, Rui-Chun; Zhou, Lian; Yang, Sai-Hong

2017-06-01

Ascertaining the petrogenesis of granitoid rocks in subduction zones holds the key for understanding the processes of how continental crust is produced. The synchronous Taoyuan and Huanggang plutons occur in two different geological units of the Paleozoic Tongbai orogen of central China. They provide an optimal opportunity for a study to address the role of the crustal basement in generating voluminous granitoid magmatism in subduction zones. The Taoyuan and Huanggang plutons have identical U-Pb zircon crystallization ages of 440-444 Ma, which are temporally related to northward subduction of the Paleotethyan Ocean. The Taoyuan samples show high SiO2 (73.36-79.16%) and low Al2O3 (12.00-13.45%) contents, Mg numbers (20.6-38.2), and Sr/Y (2.04-10.1) and (La/Yb)N (2.34-7.32) ratios with negative Eu anomalies (Eu/Eu* = 0.33-0.93). They yielded positive εNd(t) (+ 3.0 to + 6.7) and εHf(t) (+ 11.8 to + 13.2) values, elevated initial Sr isotopic ratios (0.7040-0.7057) and relatively low zircon δ18O values of 4.62-5.39‰. These suggest that they were produced through partial melting of hydrothermally altered lower crust of the accreted Erlangping oceanic arc. In contrast, the Huanggang samples exhibit variable whole-rock geochemical and isotopic compositions with SiO2 contents of 57.01-64.42 wt.%, initial Sr isotopic ratios of 0.7065-0.7078, and εNd(t) values of - 5.7 to - 9.4. Additionally, they have high zircon δ18O values of 7.57-8.45‰ and strongly negative zircon εHf(t) values of - 14.4 to - 10.5. They were suggested to have been mainly derived from ancient continental crust of the Kuanping crustal unit with the addition of 20-40% juvenile, mantle-derived material. Accordingly, the granitoids in both oceanic and continental arcs are likely to be mainly derived from intracrustal melting of their crustal basement. It is revealed by the Huanggang pluton that little net continental crust growth occurs in continental arcs, and addition of new volume of continental

Disc cutter wear and rock texture in hard rock TBM tunneling

International Nuclear Information System (INIS)

Koizumi, Yu; Tsusaka, Kimikazu; Tanimoto, Chikaosa; Nakagawa, Shigeo; Fujita, Naoya

2008-01-01

Disc cutter wear in TBM tunneling is caused by initial fragmentation of a solid rock face (the primary fragmentation) and fragmentation of residual rock pieces between a cutterhead and the face (the secondary fragmentation). In two projects through sedimentary and granitic rocks, the authors investigated the relationships between the rate of cutter wear caused by the primary fragmentation, point load index and the grain size and contents of abrasive minerals. As a result, it was found that the tensile strength and the mineral contents of rocks significantly influenced the cutter wear in both projects and thus it is necessary to take into account of rock type. (author)

Rocks Can Wow? Yes, Rocks Can Wow!

Science.gov (United States)

Hardman, Sally; Luke, Sue

2016-01-01

Rocks and fossils appear in the National Curriculum of England science programmes of study for children in year 3 (ages 7-8). A frequently asked question is "How do you make the classification of rocks engaging?" In response to this request from a school, a set of interactive activities was designed and organised by tutors and students…

Anti-glomerular basement membrane: A rare cause of renal failure in children

Directory of Open Access Journals (Sweden)

Indira Agarwal

2017-01-01

Full Text Available Anti-glomerular basement membrane (GBM disease is a rare cause of acute renal failure and known to have bad prognosis regarding renal functions recovery and patient survival specially when diagnosed late and presents with severe renal failure that requires dialysis. We report a case of 11-year-old child with acute renal failure secondary to anti-GBM disease and associated with antineutrophil cytoplasmic antibody-positive vasculitis. He was treated with plasmapheresis, steroids, and cyclophosphamide with recovery of his kidney functions.

Shear Zone-Hosted Base Metal Mineralization near Abraha ...

African Journals Online (AJOL)

Tadesse

of Arabia; B) Plan view of northern Ethiopia showing the roads and position ... within NE trending shear zone in the basement rocks with well developed alterations ...... country rocks and transported to the sites of deposition i.e. structural weak.

Relative chronology in high-grade crystalline terrain of the Eastern Ghats, India: new insights

Science.gov (United States)

Bhattacharya, S.; Kar, R.; Saw, A. K.; Das, P.

2011-01-01

The two major lithology or gneiss components in the polycyclic granulite terrain of the Eastern Ghats, India, are the supracrustal rocks, commonly described as khondalites, and the charnockite-gneiss. Many of the workers considered the khondalites as the oldest component with unknown basement and the charnockite-protoliths as intrusive into the khondalites. However, geochronological data do not corroborate the aforesaid relations. The field relations of the hornblende- mafic granulite with the two gneiss components together with geocronological data indicate that khondalite sediments were deposited on older mafic crustal rocks. We propose a different scenario: Mafic basement and supracrustal rocks were subsequently deformed and metamorphosed together at high to ultra-high temperatures - partial melting of mafic rocks producing the charnockitic melt; and partial melting of pelitic sediments producing the peraluminous granitoids. This is compatible with all the geochronological data as well as the petrogenetic model of partial melting for the charnockitic rocks in the Eastern Ghats Belt.

Groundwater chemistry, storage and dynamics in parts of Jigawa ...

African Journals Online (AJOL)

pc

fractures in the fresh basement are inte certain depth. Wright and Burgess weathering profile grade for the basement rocks of Kano State; they identified three water .... Flame photometer was used to analysed the. Cations in the laboratory. One litre Plastic containers were used for the collection of water samples in the field.

Basement membrane and interstitial proteoglycans produced by MDCK cells correspond to those expressed in the kidney cortex

DEFF Research Database (Denmark)

Erickson, A C; Couchman, J R

2001-01-01

Multiple proteoglycans (PGs) are present in all basement membranes (BM) and may contribute to their structure and function, but their effects on cell behavior are not well understood. Their postulated functions include: a structural role in maintaining tissue histoarchitecture, or aid in selective...... filtration processes; sequestration of growth factors; and regulation of cellular differentiation. Furthermore, expression PGs has been found to vary in several disease states. In order to elucidate the role of PGs in the BM, a well-characterized model of polarized epithelium, Madin-Darby canine kidney (MDCK...... core proteins or CS stubs generated by cABC treatment, revealed that both basement membrane and interstitial PGs are secreted by MDCK cells. HSPGs expressed by MDCK cells are perlecan, agrin, and collagen XVIII. Various CSPG core proteins are made by MDCK cells and have been identified as biglycan...

Rock Physics

DEFF Research Database (Denmark)

Fabricius, Ida Lykke

2017-01-01

Rock physics is the discipline linking petrophysical properties as derived from borehole data to surface based geophysical exploration data. It can involve interpretation of both elastic wave propagation and electrical conductivity, but in this chapter focus is on elasticity. Rock physics is based...... on continuum mechanics, and the theory of elasticity developed for statics becomes the key to petrophysical interpretation of velocity of elastic waves. In practice, rock physics involves interpretation of well logs including vertical seismic profiling (VSP) and analysis of core samples. The results...

Image-based modelling of lateral magma flow: the Basement Sill, Antarctica.

Science.gov (United States)

Petford, Nick; Mirhadizadeh, Seyed

2017-05-01

The McMurdo Dry Valleys magmatic system, Antarctica, provides a world-class example of pervasive lateral magma flow on a continental scale. The lowermost intrusion (Basement Sill) offers detailed sections through the now frozen particle microstructure of a congested magma slurry. We simulated the flow regime in two and three dimensions using numerical models built on a finite-element mesh derived from field data. The model captures the flow behaviour of the Basement Sill magma over a viscosity range of 1-10 4  Pa s where the higher end (greater than or equal to 10 2  Pa s) corresponds to a magmatic slurry with crystal fractions varying between 30 and 70%. A novel feature of the model is the discovery of transient, low viscosity (less than or equal to 50 Pa s) high Reynolds number eddies formed along undulating contacts at the floor and roof of the intrusion. Numerical tracing of particle orbits implies crystals trapped in eddies segregate according to their mass density. Recovered shear strain rates (10 -3 -10 -5  s -1 ) at viscosities equating to high particle concentrations (around more than 40%) in the Sill interior point to shear-thinning as an explanation for some types of magmatic layering there. Model transport rates for the Sill magmas imply a maximum emplacement time of ca 10 5 years, consistent with geochemical evidence for long-range lateral flow. It is a theoretically possibility that fast-flowing magma on a continental scale will be susceptible to planetary-scale rotational forces.

Mineral and rock chemistry of Mata da Corda Kamafugitic Rocks (Minas Gerais State, Brazil)

International Nuclear Information System (INIS)

Albuquerque Sgarbi, Patricia B. de; Valenca, Joel G.

1995-01-01

The volcanic rocks of the Mata da Corda Formation (Upper Cretaceous) in Minas Gerais, Brazil, are mafic potassic to ultra potassic rocks of kamafugitic affinity containing essentially clinopyroxenes, perovskite, magnetite and occasionally olivine, phlogopite, melilite pseudomorphs and apatite. The felsic phases are kalsilite and/or leucite pseudomorphs. The rocks are classified as mafitites, leucitites and kalsilitites. The analysis of the available data of the rocks studied, based on the relevant aspects of the main proposals for the classification of alkaline mafic to ultramafic potassic rocks leads to the conclusion that Sahama's (1974) proposal to divide potassium rich alkaline rocks in two large families is the one to which the Mata da Corda rocks adapt best. According to this and the data in the literature on the mineralogy and mineral and rock chemistries of the other similar occurrences, these rocks may be interpreted as alkaline potassic to ultra potassic rocks of hamafugitic affinity. 11 figs., 5 tabs

Investigations of possibilities to dispose of spent nuclear fuel in Lithuania: a model case. Volume 3, Generic Safety Assessment of Repository in Crystalline Rocks

International Nuclear Information System (INIS)

Motiejunas, S.; Poskas, P.

2005-01-01

In this Volume a generic safety assessment of the repository for spent nuclear fuel in crystalline rock in Lithuania is presented. Modeling of safety relevant radionuclide release from the defected canister and their transport through the near field and far field was performed. Doses to humans due to released radionuclides in the well water were calculated and compared with the dose restrictions existing in Lithuania. For this stage of generic safety assessment only two scenarios were chosen: base scenario and canister defect scenario. KBS-3 concept developed by SKB for disposal of spent nuclear fuel in Sweden was chosen as prototype for repository in crystalline basement in Lithuania. The KBS-3H design with horizontal canister emplacement is proposed as a reference design for Lithuania

Basement control of alkalic flood rhyolite magmatism of the Davis Mountains volcanic field, Trans-Pecos Texas, U.S.A.

Science.gov (United States)

Parker, Don F.; White, John C.; Ren, Minghua; Barnes, Melanie

2017-11-01

Voluminous silicic lava flows, erupted 37.4 Ma from widespread centers within the Davis Mountains Volcanic Field (DMVF), covered approximately 10,000 km2 with an initial volume as great as 1000 km3. Lava flows form three major stratigraphic units: the Star Mountain Rhyolite (minimum 220 km3) of the eastern Davis Mountains and adjacent Barilla Mountains, the Crossen Formation ( 75 km3) of the southern Davis Mountains, and the Bracks Rhyolite ( 75 km3) of the Rim Rock region west of the Davis Mountains proper. Similar extensive rhyolite lava also occurs in slightly younger units (Adobe Canyon Rhyolite, 125 km3, 37.1 Ma), Sheep Pasture Formation ( 125 km3, 36 Ma) and, less voluminously, in the Paisano central volcano ( 36.9 Ma) and younger units in the Davis Mountains. Individual lava flows from these units formed fields as extensive as 55 km and 300-m-thick. Flood rhyolite lavas of the Davis Mountains are marginally peralkaline quartz trachyte to low-silica rhyolite. Phenocrysts include alkali feldspar, clinopyroxene, FeTi oxides, and apatite, and, rarely, fayalite, as well as zircon in less peralkaline units. Many Star Mountain flows may be assigned to one of four geochemical groupings. Temperatures were moderately high, ranging from 911 to 860 °C in quartz trachyte and low silica rhyolite. We suggest that flood rhyolite magma evolved from trachyte magma by filter pressing processes, and trachyte from mafic magma in deeper seated plutons. The Davis Mountains segment of Trans-Pecos Texas overlies Grenville basement and is separated from the older Southern Granite and Rhyolite Province to the north by the Grenville Front, and from the younger Coahuila terrane to the south by the Ouachita Front. We suggest that basement structure strongly influenced the timing and nature of Trans-Pecos magmatism, probably in varying degrees of impeding the ascent of mantle-derived mafic magmas, which were produced by upwelling of asthenospheric mantle above the foundered Farallon slab

Rock History and Culture

OpenAIRE

Gonzalez, Éric

2013-01-01

Two ambitious works written by French-speaking scholars tackle rock music as a research object, from different but complementary perspectives. Both are a definite must-read for anyone interested in the contextualisation of rock music in western popular culture. In Une histoire musicale du rock (i.e. A Musical History of Rock), rock music is approached from the point of view of the people – musicians and industry – behind the music. Christophe Pirenne endeavours to examine that field from a m...

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

Directory of Open Access Journals (Sweden)

Ahmed Khalil

2016-12-01

Full Text Available 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.

Fluid flow and permeabilities in basement fault zones

Science.gov (United States)

Hollinsworth, Allan; Koehn, Daniel

2017-04-01

Fault zones are important sites for crustal fluid flow, specifically where they cross-cut low permeability host rocks such as granites and gneisses. Fluids migrating through fault zones can cause rheology changes, mineral precipitation and pore space closure, and may alter the physical and chemical properties of the host rock and deformation products. It is therefore essential to consider the evolution of permeability in fault zones at a range of pressure-temperature conditions to understand fluid migration throughout a fault's history, and how fluid-rock interaction modifies permeability and rheological characteristics. Field localities in the Rwenzori Mountains, western Uganda and the Outer Hebrides, north-west Scotland, have been selected for field work and sample collection. Here Archaean-age TTG gneisses have been faulted within the upper 15km of the crust and have experienced fluid ingress. The Rwenzori Mountains are an anomalously uplifted horst-block located in a transfer zone in the western rift of the East African Rift System. The north-western ridge is characterised by a tectonically simple western flank, where the partially mineralised Bwamba Fault has detached from the Congo craton. Mineralisation is associated with hydrothermal fluids heated by a thermal body beneath the Semliki rift, and has resulted in substantial iron oxide precipitation within porous cataclasites. Non-mineralised faults further north contain foliated gouges and show evidence of leaking fluids. These faults serve as an analogue for faults associated with the Lake Albert oil and gas prospects. The Outer Hebrides Fault Zone (OHFZ) was largely active during the Caledonian Orogeny (ca. 430-400 Ma) at a deeper crustal level than the Ugandan rift faults. Initial dry conditions were followed by fluid ingress during deformation that controlled its rheological behaviour. The transition also altered the existing permeability. The OHFZ is a natural laboratory in which to study brittle fault

Distribution of two basement membrane proteoglycans through hair follicle development and the hair growth cycle in the rat

DEFF Research Database (Denmark)

Couchman, J R; King, J L; McCarthy, K J

1990-01-01

The distribution of two distinct populations of basement membrane proteoglycans has been monitored through hair growth development in the rat embryo and subsequent hair growth cycle. An antiserum against a small heparan sulfate proteoglycan uniformly stained the dermal-epidermal junction...... of embryonic rats throughout the period of hair follicle formation. On the other hand, monoclonal antibodies recognizing a basement membrane-specific chondroitin sulfate proteoglycan only weakly stained 16-d embryo dermal-epidermal junction, but strong staining was associated with hair follicle buds...... as they developed. Through the hair growth cycle, it was found that the heparan sulfate proteoglycan persisted around the follicles, while the chondroitin sulfate proteoglycan decreased in amount through catagen until it was undetectable at the base and dermal papilla of the telogen follicle. As anagen commenced...

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.

(U-Th)/He thermochronometry reveals Pleistocene punctuated deformation and synkinematic hematite mineralization in the Mecca Hills, southernmost San Andreas Fault zone

Science.gov (United States)

Moser, Amy C.; Evans, James P.; Ault, Alexis K.; Janecke, Susanne U.; Bradbury, Kelly K.

2017-10-01

The timing, tempo, and processes of punctuated deformation in strike-slip fault systems are challenging to resolve in the rock record. Faults in the Mecca Hills, adjacent to the southernmost San Andreas Fault, California, accommodate active deformation and exhumation in the Plio-Pleistocene sedimentary rocks and underlying crystalline basement. We document the spatiotemporal patterns of San Andreas Fault-related deformation as recorded in crystalline basement rocks of the Mecca Hills using fault microstructural observations, geochemical data, and hematite (n = 24) and apatite (n = 44) (U-Th)/He (hematite He, apatite He) thermochronometry data. Reproducible mean hematite He dates from minor hematite-coated fault surfaces in the Painted Canyon Fault damage zone range from ∼0.7-0.4 Ma and are younger than ∼1.2 Ma apatite He dates from adjacent crystalline basement host rock. These data reveal concomitant Pleistocene pulses of fault slip, fluid flow, and synkinematic hematite mineralization. Hematite textures, crystal morphology, and hematite He data patterns imply some damage zone deformation occurred via cyclic crack-seal and creep processes. Apatite He data from crystalline basement define distinct date-eU patterns and indicate cooling across discrete fault blocks in the Mecca Hills. Uniform ∼1.2 Ma apatite He dates regardless of eU are located exclusively between the Painted Canyon and Platform faults. Outside of this fault block, samples yield individual apatite He dates from ∼30-1 Ma that define a positive apatite He date-eU correlation. These patterns reveal focused exhumation away from the main trace of the San Andreas Fault at ∼1.2 Ma. Low-temperature thermochronometry of fault-related rocks provides an unprecedented window into the 105-106-yr record of San Andreas Fault-related deformation in the Mecca Hills and documents hematite deformation mechanisms that may be operative in other strike-slip faults world-wide.

The Geology of the Bergamasc Alps Lombardia Italy

NARCIS (Netherlands)

Sitter, de L.U.; Sitter-Koomans, de C.M.

1949-01-01

In the Bergamasc Alps we have observed one major unconformity between the Basement rock and the overlying Permian. The total absence of any recognisable Palaeozoic sedimentary rocks accentuates this unconformity, and moreover this enormous hiatus makes the dating of any Palaeozoic event impossible.

Geophysical modeling of the northern Appalachian Brompton-Cameron, Central Maine, and Avalon terranes under the New Jersey Coastal Plain

Science.gov (United States)

Maguire, T.J.; Sheridan, R.E.; Volkert, R.A.

2004-01-01

A regional terrane map of the New Jersey Coastal Plain basement was constructed using seismic, drilling, gravity and magnetic data. The Brompton-Cameron and Central Maine terranes were coalesced as one volcanic island arc terrane before obducting onto Laurentian, Grenville age, continental crust in the Taconian orogeny [Rankin, D.W., 1994. Continental margin of the eastern United States: past and present. In: Speed, R.C., (Ed.), Phanerozoic Evolution of North American Continent-Ocean Transitions. DNAG Continent-Ocean Transect Volume. Geological Society of America, Boulder, Colorado, pp. 129-218]. Volcanic island-arc rocks of the Avalon terrane are in contact with Central Maine terrane rocks in southern Connecticut where the latter are overthrust onto the Brompton-Cameron terrane, which is thrust over Laurentian basement. Similarities of these allochthonous island arc terranes (Brompton-Cameron, Central Maine, Avalon) in lithology, fauna and age suggest that they are faulted segments of the margin of one major late Precambrian to early Paleozoic, high latitude peri-Gondwana island arc designated as "Avalonia", which collided with Laurentia in the early to middle Paleozoic. The Brompton Cameron, Central Maine, and Avalon terranes are projected as the basement under the eastern New Jersey Coastal Plain based on drill core samples of metamorphic rocks of active margin/magmatic arc origin. A seismic reflection profile across the New York Bight traces the gentle dipping (approximately 20 degrees) Cameron's Line Taconian suture southeast beneath allochthonous Avalon and other terranes to a 4 sec TWTT depth (approximately 9 km) where the Avalonian rocks are over Laurentian crust. Gentle up-plunge (approximately 5 degrees) projections to the southwest bring the Laurentian Grenville age basement and the drift-stage early Paleozoic cover rocks to windows in Burlington Co. at approximately 1 km depth and Cape May Co. at approximately 2 km depths. The antiformal Shellburne

Methodology for deriving hydrogeological input parameters for safety-analysis models - application to fractured crystalline rocks of Northern Switzerland

International Nuclear Information System (INIS)

Vomvoris, S.; Andrews, R.W.; Lanyon, G.W.; Voborny, O.; Wilson, W.

1996-04-01

Switzerland is one of many nations with nuclear power that is seeking to identify rock types and locations that would be suitable for the underground disposal of nuclear waste. A common challenge among these programs is to provide engineering designers and safety analysts with a reasonably representative hydrogeological input dataset that synthesizes the relevant information from direct field observations as well as inferences and model results derived from those observations. Needed are estimates of the volumetric flux through a volume of rock and the distribution of that flux into discrete pathways between the repository zones and the biosphere. These fluxes are not directly measurable but must be derived based on understandings of the range of plausible hydrogeologic conditions expected at the location investigated. The methodology described in this report utilizes conceptual and numerical models at various scales to derive the input dataset. The methodology incorporates an innovative approach, called the geometric approach, in which field observations and their associated uncertainty, together with a conceptual representation of those features that most significantly affect the groundwater flow regime, were rigorously applied to generate alternative possible realizations of hydrogeologic features in the geosphere. In this approach, the ranges in the output values directly reflect uncertainties in the input values. As a demonstration, the methodology is applied to the derivation of the hydrogeological dataset for the crystalline basement of Northern Switzerland. (author) figs., tabs., refs

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)

Rapid formation of rock armour for soil - rock fragment mixture during simulated rainfall

Science.gov (United States)

Poultney, E.; McGrath, G. S.; Hinz, C.

2009-04-01

Preventing erosion is an important issue in disturbed semi-arid and arid landscapes. This is in particular of highest importance for mining companies while undertaking land rehabilitation. An onsite investigation of the impact of surface rock fragments on erosion was conducted at Telfer goldmine in the Great Sandy Desert, Western Australia. The study site is a waste rock dump designed to mimic the concave slope of a natural mesa to both discourage erosion and blend in with its natural surroundings. Four treatments were used to construct the slope: two are topsoil mixed with rock fragments, and two are unmixed topsoil. A field study investigating erosion rills, particle size distribution, rock fragment coverage surface roughness and vegetation was carried out to determine changes down and across slope. The treatments constructed by mixing topsoil and rock fragments are more stable and show rock fragment distributions that more closely resemble patterns found on natural mesas surrounding Telfer. A controlled study using trays of topsoil mixed with rock fragment volumes of 50%, 60%, 70% and 80% were used to investigate how varying mixtures of rock fragments and topsoil erode using rainfall intensities between 20 and 100 mm h-1. Two runs of 25 minutes each were used to assess the temporal evolution of rock armouring. Surface coverage results converged for the 50%, 60% and 70% mixtures after the first run to coverage of about 90%, suggesting that fine sediment proportion does not affect rate and degree of rock armouring.

Chemistry of reference waters of the crystalline basement of Northern Switzerland for safety assessment studies

International Nuclear Information System (INIS)

Pearson, F.J. Jr.; Scholtis, A.

1993-08-01

The chemistry of groundwater in formations being considered as host rocks for nuclear waste repositories must be known to assess the performance of those repositories, and as media for laboratory experiments. Two potential repository siting areas in the crystalline basement of northern Switzerland are being assessed. This report gives the chemistry of water in both areas for reference use in this assessment. The western area is in the region defined by the Kaisten, Leuggern, Boettstein, and Zurzach boreholes. The western reference water is based on samples from the Leuggern, Boettstein, and Zurzach boreholes. Kaisten water is of higher salinity (1.3 g/l). The concentration ranges of the reference water include Kaisten values, however. High quality samples and analyses, particularly from long term sampling at Zurzach and Leuggern, define the concentration ranges of many trace elements. The definition of this water assumes saturation with respect to calcite, baryte, fluorites, chalcedony, and kaolinite. The reference pe is based on the assumption that dissolved iron concentrations are controlled by the solubility of the mineral goethite, and is consistent with other redox indicators such as the measured Pt-electrode potential and the ratio of dissolved As(V) to As(III). The eastern area is characterized by the Siblingen boreholes. The eastern reference water is a Na-HCO 3 -SO 4 -(Cl) type with a total dissolved solids content of about 0.5 g/l. Only three samples taken during borehole drilling are available to define this water, so it can be specified in less detail and with less precision than the western water. Its definition assumes saturation with respect to calcite, baryte, and fluorites. The samples permit only a broad definition of its oxidation potential and content of redox-sensitive metals such as Fe, As, Mn, and U. Trace element data for the most part are lacking. (author) figs., tabs., 28 refs

Development of artificial soft rock

International Nuclear Information System (INIS)

Kishi, Kiyoshi

1995-01-01

When foundation base rocks are deeper than the level of installing structures or there exist weathered rocks and crushed rocks in a part of base rocks, often sound artificial base rocks are made by substituting the part with concrete. But in the construction of Kashiwazaki Kariwa Nuclear Power Station of Tokyo Electric Power Co., Inc., the foundation base rocks consist of mudstone, and the stiffness of concrete is large as compared with the surrounding base rocks. As the quality of the substituting material, the nearly same stiffness as that of the surrounding soft rocks and long term stability are suitable, and the excellent workability and economical efficiency are required, therefore, artificial soft rocks were developed. As the substituting material, the soil mortar that can obtain the physical property values in stable form, which are similar to those of Nishiyama mudstone, was selected. The mechanism of its hardening and the long term stability, and the manufacturing plant are reported. As for its application to the base rocks of Kashiwazaki Kariwa Nuclear Power Station, the verification test at the site and the application to the base rocks for No. 7 plant reactor building and other places are described. (K.I.)

Pentoxifylline Ameliorates Glomerular Basement Membrane Ultrastructural Changes Caused by Gentamicin Administration in Rats

Directory of Open Access Journals (Sweden)

Nenad Stojiljković

2009-08-01

Full Text Available Gentamicin is commonly used for the treatment of severe gram negative bacterial infections but inevi-tably cause renal failure during prolonged use. The aim of our study was to emphasize protective effects of pentoxifylline on glomerular basement membrane (GBM alterations induced by gentamicin in rats. Experiments were done on 40 male Wistar rats divided in three experimental groups. GM-group was treated daily with gentamicin in dose of 100 mg/kg during 8 days. PTX-group was treated daily with pentoxifylline in dose of 45 mg/kg and the same dose of gentamicin as in GM-group during 8 days. The control group received 1 ml/day saline intraperitoneally. Morphometric parameter measured during the analysis was glomerular basement membrane thickness. In GM-group of animals glomeruli were en-larged and GMB was diffusely and unequally thickened with neutrophil cells infiltration. In proximal tu-bules epithelial cells, vacuolization of cytoplasm with coagulation-type necrosis were observed. In PTX-group of animals glomeruli were somewhat enlarged and GBM was thickened only in some segments. Coagulation-type necrosis was not found. Blood urea and serum creatinine concentration in GM-group were significantly elevated in comparison with PTX-group while potassium level was decreased. Our results suggest that PTX has protective effects on GBM and proximal tubules in GM-treated rats.

77 FR 51993 - Western Technical College; Notice of Availability of Environmental Assessment

Science.gov (United States)

2012-08-28

... project area (Source: Normandeau Associates, Inc., 2002)... Table 6. Sustained and burst swimming speeds... time, followed by a layer of Potsdam sandstone surface rock. The Potsdam sandstone layer of this... layer is Archaean-age basement rock, namely highly metamorphic gneiss, granite, and schists. The basin...

Database for Regional Geology, Phase 1: A Tool for Informing Regional Evaluations of Alternative Geologic Media and Decision Making

Energy Technology Data Exchange (ETDEWEB)

Perry, Frank Vinton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kelley, Richard E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Birdsell, Suzanne M. [Clark Univ., Worcester, MA (United States); Lugo, Alexander Bryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dobson, Patrick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, James [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2014-11-12

Reported is progress in the following areas: Phase 1 and 2 websites for the regional geology GIS database; terrane maps of crystalline basement rocks; inventory of shale formations in the US; and rock properties and in-situ conditions for shale estimated from sonic velocity measurements.

Basement membrane abnormalities in human eyes with diabetic retinopathy

DEFF Research Database (Denmark)

Ljubimov, A V; Burgeson, R E; Butkowski, R J

1996-01-01

Vascular and parenchymal basement membranes (BMs) are thickened in diabetes, but alterations in individual BM components in diabetic eyes, especially in diabetic retinopathy (DR), are obscure. To identify abnormalities in the distribution of specific constituents, we analyzed cryostat sections...... of human eyes obtained at autopsy (seven normal, five diabetic without DR, and 13 diabetic with DR) by immunofluorescence with antibodies to 30 BM and extracellular matrix components. In non-DR eyes, no qualitative changes of ocular BM components were seen. In some DR corneas, epithelial BM was stained...... discontinuously for laminin-1, entactin/nidogen, and alpha3-alpha4 Type IV collagen, in contrast to non-DR corneas. Major BM alterations were found in DR retinas compared to normals and non-DR diabetics. The inner limiting membrane (retinal BM) of DR eyes had accumulations of fibronectin (including cellular...

Petrology and Geochemistry of Neoproterozoic Arc Plutons Beneath the Atlantic Coastal Plain, SRS, SC

Energy Technology Data Exchange (ETDEWEB)

Maryak, M.

1998-10-21

In this report is presented first a brief review of the regional geologic setting of the Savannah River Site, descriptions of the plutonic rock units sampled here, whole rock geochemical data on the plutonic igneous rocks, and finally, a discussion of how the crystalline basement rocks of the Savannah River Site formed and how they may correlate with other terranes exposed in the Piedmont of the Carolinas, Georgia, and Virginia.

H2-rich and Hydrocarbon Gas Recovered in a Deep Precambrian Well in Northeastern Kansas

International Nuclear Information System (INIS)

Newell, K. David; Doveton, John H.; Merriam, Daniel F.; Lollar, Barbara Sherwood; Waggoner, William M.; Magnuson, L. Michael

2007-01-01

In late 2005 and early 2006, the WTW Operating, LLC (W.T.W. Oil Co., Inc.) no. 1 Wilson well (T.D. = 5772 ft; 1759.3 m) was drilled for 1826 ft (556.6 m) into Precambrian basement underlying the Forest City Basin in northeastern Kansas. Approximately 4500 of the 380,000 wells drilled in Kansas penetrate Precambrian basement. Except for two previous wells drilled into the arkoses and basalts of the 1.1-Ga Midcontinent Rift and another well drilled in 1929 in basement on the Nemaha Uplift east of the Midcontinent Rift, this well represents the deepest penetration into basement rocks in the state to date. Granite is the typical lithology observed in wells that penetrate the Precambrian in the northern Midcontinent. Although no cores were taken to definitively identify lithologies, well cuttings and petrophysical logs indicate that this well encountered basement metamorphic rocks consisting of schist, gneiss, and amphibolitic gneiss, all cut by aplite dikes.The well was cased and perforated in the Precambrian, and then acidized. After several days of swabbing operations, the well produced shows of low-Btu gas, dominated by the non-flammable component gases of nitrogen (20%), carbon dioxide (43%), and helium (1%). Combustible components include methane (26%), hydrogen (10%), and higher molecular-weight hydrocarbons (1%). Although Coveney and others [Am. Assoc. Petroleum Geologists Bull., v. 71, no, 1, p. 39-48, 1987] identified H 2 -rich gas in two wells located close to the Midcontinent Rift in eastern Kansas, this study indicates that high levels of H 2 may be a more widespread phenomenon than previously thought. Unlike previous results, the gases in this study have a significant component of hydrocarbon gas, as well as H 2 , N 2 , and CO 2 . Although redox reactions between iron-bearing minerals and groundwater are a possible source of H 2 in the Precambrian basement rocks, the hydrocarbon gas does not exhibit the characteristics typically associated with proposed

Teaching the Rock Cycle with Ease.

Science.gov (United States)

Bereki, Debra

2000-01-01

Describes a hands-on lesson for teaching high school students the concept of the rock cycle using sedimentary, metamorphic, and igneous rocks. Students use a rock cycle diagram to identify pairs of rocks. From the rock cycle, students explain on paper how their first rock became the second rock and vice versa. (PVD)

Recreating Rocks

DEFF Research Database (Denmark)

Posth, Nicole R

2008-01-01

Nicole Posth and colleagues spent a month touring South African rock formations in their quest to understand the origin of ancient iron and silicate layers.......Nicole Posth and colleagues spent a month touring South African rock formations in their quest to understand the origin of ancient iron and silicate layers....

Hydrological characteristics of Japanese rock

International Nuclear Information System (INIS)

Ijiri, Yuji; Sawada, Atsushi; Akahori, Kuniaki

1999-11-01

It is crucial to evaluate the hydrogeological characteristics of rock in Japan in order to assess the performance of geosphere. This report summarizes the hydrogeological characteristics of various rock types obtained from broad literature surveys and the fields experiments at the Kamaishi mine in northern Japan and at the Tono mine in central Japan. It is found that the hydraulic conductivity of rock mass ranges from 10 -9 m/s to 10 -8 m/s, whereas the hydraulic conductivity of fault zone ranges from 10 -9 m/s to 10 -3 m/s. It is also found that the hydraulic conductivity tends to decrease with depth. Therefore, the hydraulic conductivity of rock mass at the depth of a repository will be smaller than above values. From the investigations at outcrops and galleries throughout the country, fractures are observed as potential pathways in all rock types. All kinds of crystalline rocks and pre-Neogene sedimentary rocks are classified as fractured media where fracture flow is dominant. Among these rocks, granitic rock is considered the archetype fractured media. On the other hand, andesite, tuff and Neogene sedimentary rocks are considered as intermediate between fractured media and porous media where flow in fractures as well as in rock matrix are significant. (author)

Immunological characterization of a basement membrane-specific chondroitin sulfate proteoglycan

DEFF Research Database (Denmark)

McCarthy, K J; Accavitti, M A; Couchman, J R

1989-01-01

with the proteoglycan preparation and four mAbs recognizing the core protein of a high-density, buoyant chondroitin sulfate proteoglycan were raised. Confirmation of antibody specificity was carried out by the preparation of affinity columns made from each of the mAbs. Chondroitin sulfate proteoglycans (CSPGs) were...... (Mr = 5-6 x 10(5)), with a core protein of Mr = approximately 1.5-1.6 x 10(5) and composed exclusively of chondroitin sulfate chains with an average Mr = 1.6-1.8 x 10(4). In addition, a CSPG was purified from adult rat kidney, whose core protein was also Mr = 1.6 x 10(5). The proteoglycan and its core...... sulfate proteoglycans, it therefore appears that at least one CSPG is a widespread basement membrane component....

Groundwater Exploration in the Basement Complex Around Chibok ...

African Journals Online (AJOL)

admin

Available online at http://www.ajol.info/index.php/njbas/index. Nigerian ... fresh crystalline rock at shallow depth. Keywords: ... has been deformed either by deep fracturing,. Study Area .... logarithmic paper for further processing. Eight VES ...

Rock Goes to School on Screen: A Model for Teaching Non-"Learned" Musics Derived from the Films "School of Rock" (2003) and "Rock School" (2005)

Science.gov (United States)

Webb, Michael

2007-01-01

What can be learned from two films with "rock" and "school" in their titles, about rock in school and about music and schooling more broadly? "School of Rock" (2003), a "family comedy," and "Rock School" (2005), a documentary, provoke a range of questions, ideological and otherwise, surrounding the inclusion of rock in formal instructional…

Faults in Paleozoic basement and their participation in Alpine deformation of Greater Caucasus – evidences from materials of restored (balanced) sections in folded sedimentary cover

Science.gov (United States)

Yakovlev, Fedor

2015-04-01

Method. As each fold has information about strain, numerous folds (0.1-1 km width) inside of hinterland (stripe about 1000 x 50 km) of Greater Caucasus (GC) allow to restore structure for whole sedimentary cover. Material of 24 detailed sections of 510 km total actual length in three regions was used for restoration of structure. These sections were split on 505 domains as associations of 2-5 folds. Three parameters of morphology were measured in these domains: dip of axial plain, dip of envelope plain, value of shortening as interlimb angle [1, 2, 3]. Because these parameters correlate with ellipsoid (ellipse) of strain for domain, sequence of three kinematic operations allow to restore actual state of domain to pre-folded state (from ellipse to circle): rotation to horizontal position of envelope plain, horizontal simple shear to vertical axial plain and vertical flattening (pure shear). Aggregation of chain of pre-folded domains is forming a pre-folded state of whole section, and it allows to calculate of shortening value. For correct detailing of strain study, 78 "structural cells" were formed by aggregation of 5-10 domains in each cell. Some additional observations and calculations allow to find initial and post-folded thickness of sedimentary cover, depth of cover bottom, virtual position of cover top (amplitude of erosion) for all tectonic cells. The received result for 78 cells allowed to understand the main features of GC structure, to see a distribution of basement top depth, to give behavior pattern of the basement and to find a role of faults in shortening of the basement and of sedimentary cover. Results. Three regions of GC were studied: North-Western Caucasus (NWC) [1], Chiaur tectonic zone in South Ossetia (ChZ) and two zones in South-Eastern Caucasus - Tfan Zone (TZ) and Shakhdag zone (ShZ) [3]. The shortening values for structural cells were found as 49% in average for ShZ (with deviations 37÷62%), 55% for TZ (36÷67%), 57% for ChZ (46÷67%) and

Grinding into Soft, Powdery Rock

Science.gov (United States)

2004-01-01

This hole in a rock dubbed 'Clovis' is the deepest hole drilled so far in any rock on Mars. NASA's Mars Exploration Rover Spirit captured this view with its microscopic imager on martian sol 217 (Aug. 12, 2004) after drilling 8.9 millimeters (0.35 inch) into the rock with its rock abrasion tool. The view is a mosaic of four frames taken by the microscopic imager. The hole is 4.5 centimeters (1.8 inches) in diameter. Clovis is key to a developing story about environmental change on Mars, not only because it is among the softest rocks encountered so far in Gusev Crater, but also because it contains mineral alterations that extend relatively deep beneath its surface. In fact, as evidenced by its fairly crumbly texture, it is possibly the most highly altered volcanic rock ever studied on Mars. Scientific analysis shows that the rock contains higher levels of the elements sulfur, chlorine, and bromine than are normally encountered in basaltic rocks, such as a rock dubbed 'Humphrey' that Spirit encountered two months after arriving on Mars. Humphrey showed elevated levels of sulfur, chlorine, and bromine only in the outermost 2 millimeters (less than 0.1 inch) of its surface. Clovis shows elevated levels of the same elements along with the associated softness of the rock within a borehole that is 4 times as deep. Scientists hope to compare Clovis to other, less-altered rocks in the vicinity to assess what sort of water-based processes altered the rock. Hypotheses include transport of sulfur, chlorine, and bromine in water vapor in volcanic gases; hydrothermal circulation (flow of volcanically heated water through rock); or saturation in a briny soup containing the same elements. In this image, very fine-grained material from the rock has clumped together by electrostatic attraction and fallen into the borehole. NASA/JPL/Cornell/USGS

Ultrastructural localization of the core protein of a basement membrane-specific chondroitin sulfate proteoglycan in adult rat skin

DEFF Research Database (Denmark)

McCarthy, K J; Horiguchi, Y; Couchman, J R

1990-01-01

Basement membranes are complex extracellular matrices present at epithelial/mesenchymal interfaces of tissues. The dermal-epidermal junction has been shown to contain numerous components, some of the most well known being laminin, types IV and VII collagens, heparan sulfate proteoglycan, fibronec...

Expression of periglandular tenascin-C and basement membrane laminin in normal prostate, benign prostatic hyperplasia and prostate carcinoma

NARCIS (Netherlands)

Xue, Y.; Li, J.; Latijnhouwers, M. A.; Smedts, F.; Umbas, R.; Aalders, T. W.; Debruyne, F. M.; de la Rosette, J. J.; Schalken, J. A.

1998-01-01

To evaluate the structural relationship of the distribution between tenascin (tenascin-C, an extra-cellular matrix glycoprotein involved in stromal-epithelial interactions in both normal and pathological conditions) and laminin, an important component of the basement membrane, in normal and

Identification and characterization of rock slope instabilities in Val Canaria (TI, Switzerland) based on field and DEM analyses

Science.gov (United States)

Ponzio, Maria; Pedrazzini, Andrea; Matasci, Battista; Jaboyedoff, Michel

2013-04-01

In Alpine areas rockslides and rock avalanches represent common gravitational hazards that potentially constitute a danger for people and infrastructures. The aim of this study is to characterize and understand the different factors influencing the distribution of large slope instabilities affecting the Val Canaria (southern Switzerland). In particular the importance of the tectonic and lithological settings as well as the impact of the groundwater circulations are investigated in detail. Val Canaria is a SW-NE trending lateral valley that displays potential large rock slope failure. Located just above one of the main N-S communication way (Highway, Railway) through the Alps, the development of large instabilities in the Val Canaria might have dramatic consequences for the main valley downstream. The dominant geological structure of the study area is the presence of a major tectonic boundary separating two basement nappes, constituted by gneissic lithologies, i.e. the Gotthard massif and the Lucomagno nappe that are located in the northern and southern part of the valley respectively. The basement units are separated by meta-sediments of Piora syncline composed by gypsum, dolomitic breccia and fractured calc-mica schists. Along with detailed geological mapping, the use of remote sensing techniques (Aerial and Terrestrial Laser Scanning) allows us to propose a multi-disciplinary approach that combines geological mapping and interpretation with periodic monitoring of the most active rockslide areas. A large array of TLS point cloud datasets (first acquisition in 2006) constitute a notable input, for monitoring purposes, and also for structural, rock mass characterization and failure mechanism interpretations. The analyses highlighted that both valley flanks are affected by deep-seated gravitational slope deformation covering a total area of about 8 km2 (corresponding to 40% of the catchment area). The most active area corresponds to the lower part of the valley

THM-coupled modeling of selected processes in argillaceous rock relevant to rock mechanics

International Nuclear Information System (INIS)

Czaikowski, Oliver

2012-01-01

Scientific investigations in European countries other than Germany concentrate not only on granite formations (Switzerland, Sweden) but also on argillaceous rock formations (France, Switzerland, Belgium) to assess their suitability as host and barrier rock for the final storage of radioactive waste. In Germany, rock salt has been under thorough study as a host rock over the past few decades. According to a study by the German Federal Institute for Geosciences and Natural Resources, however, not only salt deposits but also argillaceous rock deposits are available at relevant depths and of extensions in space which make final storage of high-level radioactive waste basically possible in Germany. Equally qualified findings about the suitability/unsuitability of non-saline rock formations require fundamental studies to be conducted nationally because of the comparatively low level of knowledge. The article presents basic analyses of coupled mechanical and hydraulic properties of argillaceous rock formations as host rock for a repository. The interaction of various processes is explained on the basis of knowledge derived from laboratory studies, and open problems are deduced. For modeling coupled processes, a simplified analytical computation method is proposed and compared with the results of numerical simulations, and the limits to its application are outlined. (orig.)

Seismic response of rock joints and jointed rock mass

International Nuclear Information System (INIS)

Ghosh, A.; Hsiung, S.M.; Chowdhury, A.H.

1996-06-01

Long-term stability of emplacement drifts and potential near-field fluid flow resulting from coupled effects are among the concerns for safe disposal of high-level nuclear waste (HLW). A number of factors can induce drift instability or change the near-field flow patterns. Repetitive seismic loads from earthquakes and thermal loads generated by the decay of emplaced waste are two significant factors. One of two key technical uncertainties (KTU) that can potentially pose a high risk of noncompliance with the performance objectives of 10 CFR Part 60 is the prediction of thermal-mechanical (including repetitive seismic load) effects on stability of emplacement drifts and the engineered barrier system. The second KTU of concern is the prediction of thermal-mechanical-hydrological (including repetitive seismic load) effects on the host rock surrounding the engineered barrier system. The Rock Mechanics research project being conducted at the Center for Nuclear Waste Regulatory Analyses (CNWRA) is intended to address certain specific technical issues associated with these two KTUs. This research project has two major components: (i) seismic response of rock joints and a jointed rock mass and (ii) coupled thermal-mechanical-hydrological (TMH) response of a jointed rock mass surrounding the engineered barrier system (EBS). This final report summarizes the research activities concerned with the repetitive seismic load aspect of both these KTUs

HYDROGEOLOGICAL SIGNIFICANCE OF GEOELECTRIC ...

African Journals Online (AJOL)

... basement complex rock and the sedimentary rock of Abeokuta formation. Thus for Ijebu-ode and its environs, a thorough geophysical survey is required before citing a borehole to guide against failure or dry hole. KEY WORDS: Aquifer, Coarse sand, Resistivity, Compacted Clay, Borehole. Global Jnl Geological Sciences.

Effects of confinement on rock mass modulus: A synthetic rock mass modelling (SRM study

Directory of Open Access Journals (Sweden)

I. Vazaios

2018-06-01

Full Text Available The main objective of this paper is to examine the influence of the applied confining stress on the rock mass modulus of moderately jointed rocks (well interlocked undisturbed rock mass with blocks formed by three or less intersecting joints. A synthetic rock mass modelling (SRM approach is employed to determine the mechanical properties of the rock mass. In this approach, the intact body of rock is represented by the discrete element method (DEM-Voronoi grains with the ability of simulating the initiation and propagation of microcracks within the intact part of the model. The geometry of the pre-existing joints is generated by employing discrete fracture network (DFN modelling based on field joint data collected from the Brockville Tunnel using LiDAR scanning. The geometrical characteristics of the simulated joints at a representative sample size are first validated against the field data, and then used to measure the rock quality designation (RQD, joint spacing, areal fracture intensity (P21, and block volumes. These geometrical quantities are used to quantitatively determine a representative range of the geological strength index (GSI. The results show that estimating the GSI using the RQD tends to make a closer estimate of the degree of blockiness that leads to GSI values corresponding to those obtained from direct visual observations of the rock mass conditions in the field. The use of joint spacing and block volume in order to quantify the GSI value range for the studied rock mass suggests a lower range compared to that evaluated in situ. Based on numerical modelling results and laboratory data of rock testing reported in the literature, a semi-empirical equation is proposed that relates the rock mass modulus to confinement as a function of the areal fracture intensity and joint stiffness. Keywords: Synthetic rock mass modelling (SRM, Discrete fracture network (DFN, Rock mass modulus, Geological strength index (GSI, Confinement

Rock Physical Interpretation of the Relationship between Dynamic and Static Young's Moduli of Sedimentary Rocks

Science.gov (United States)

Takahashi, T.

2017-12-01

The static Young's modulus (deformability) of a rock is indispensable for designing and constructing tunnels, dams and underground caverns in civil engineering. Static Young's modulus which is an elastic modulus at large strain level is usually obtained with the laboratory tests of rock cores sampled in boreholes drilled in a rock mass. A deformability model of the entire rock mass is then built by extrapolating the measurements based on a rock mass classification obtained in geological site characterization. However, model-building using data obtained from a limited number of boreholes in the rock mass, especially a complex rock mass, may cause problems in the accuracy and reliability of the model. On the other hand, dynamic Young's modulus which is the modulus at small strain level can be obtained from seismic velocity. If dynamic Young's modulus can be rationally converted to static one, a seismic velocity model by the seismic method can be effectively used to build a deformability model of the rock mass. In this study, we have, therefore, developed a rock physics model (Mavko et al., 2009) to estimate static Young's modulus from dynamic one for sedimentary rocks. The rock physics model has been generally applied to seismic properties at small strain level. In the proposed model, however, the sandy shale model, one of rock physics models, is extended for modeling the static Young's modulus at large strain level by incorporating the mixture of frictional and frictionless grain contacts into the Hertz-Mindlin model. The proposed model is verified through its application to the dynamic Young's moduli derived from well log velocities and static Young's moduli measured in the tri-axial compression tests of rock cores sampled in the same borehole as the logs were acquired. This application proves that the proposed rock physics model can be possibly used to estimate static Young's modulus (deformability) which is required in many types of civil engineering applications

Spumiform basement membrane aberrations in the microvasculature of the midbrain periaqueductal gray region in hamster : Rostro-caudal pathogenesis?

NARCIS (Netherlands)

Gerrits, P.O.; Kortekaas, R.; de Weerd, Heleen; Luiten, P.G.M.; van der Want, J.J.L.; Veening, Jan

2013-01-01

Spumiform basement membrane degeneration (sbmd) is a specific kind of aberration present in the capillaries of the midbrain periaqueductal gray (PAG) region of the senescent hamster. These capillaries, separated by the ependymal cell layer, are bordering the Sylvian cerebral aqueduct. The aqueduct,

Spumiform basement membrane aberrations in the microvasculature of the midbrain periaqueductal gray region in hamster: rostro-caudal pathogenesis?

NARCIS (Netherlands)

Gerrits, P.O.; Kortekaas, R.; Weerd, H. de; Luiten, P.G.M.; Want, J.J. van der; Veening, J.G.

2013-01-01

Spumiform basement membrane degeneration (sbmd) is a specific kind of aberration present in the capillaries of the midbrain periaqueductal gray (PAG) region of the senescent hamster. These capillaries, separated by the ependymal cell layer, are bordering the Sylvian cerebral aqueduct. The aqueduct,

Basement membrane heparan sulfate proteoglycan from the L2 rat yolk sac carcinoma

DEFF Research Database (Denmark)

Fenger, M; Wewer, U; Albrechtsen, R

1984-01-01

Heparan sulfate proteoglycan from the L2 rat yolk sac carcinoma has been purified and partially characterized. The proteoglycan has an apparent Mr of 750 000, 35% of which represents the core protein. The core protein seems to be homogeneous, whereas the heparan sulfate chains are heterogeneous...... with an Mr of about 50 000-70 000, with 30% of the glucosamine being N-sulfated. Antibodies raised against the core protein of the heparan sulfate proteoglycan reacted with basement membranes of various rat and human tissue....

Application of AMT in detecting deep geological structures in Lejia district of Xiangshan uranium ore field

International Nuclear Information System (INIS)

Duan Shuxin; Liu Hu

2014-01-01

In recent years, exploration in Xiangshan uranium ore field shows that the intersection of faults and the interface of different rock formation and the basement is an important sign of deep ore- prospecting. In order to evaluate deep uranium resource in Lejia district, audio magnetotelluric method (AMT) was undertaken to carry out profile investigation. With that method, we discerned the interface of different rock formation and the basement successfully, and faults in the deep, which provides a good basis for the prediction of deep uranium resource. Drilling results show that AMT method has an obvious advantage in detecting deep geological structures in Xiangshan. (authors)

The Rock Cycle

Science.gov (United States)

Singh, Raman J.; Bushee, Jonathan

1977-01-01

Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

Water-rock interaction in a high-FeO olivine rock in nature

International Nuclear Information System (INIS)

Hellmuth, K.H.; Lindberg, A.; Tullborg, E.L.

1992-12-01

The long-term behaviour in nature of high-FeO olivine rock in contact with surface water has been studied at the Lovasjaervi instrusion, SE-Finland. The rock has been proposed as a high-capasity, higly reactive redox-buffer backfill in a repository for spent fuel. Favourable groundwater chemistry is a major parameter relevant to safety of such a repository. Reducing conditions favour the retardation of long-lived, redox-sensitive radionuclides. Weathering influences have been studied at the natural outcrop of the rock mass. The interaction of oxidizing surface waters with rock at greater depths has been studied by using fissure filling minerals. Investigation of weathered rock from the outcrop indicates that the olivine rock is highly reactive on a geological time scale and its redox capasity is available although the instrusion as a whole is surprisingly well preserved. The fissure fillings studied allow the conclusion that oxygen seems to be efficiently removed from intruding surface water. Oxidation seem to have caused visible effects only along very conducting fractures and near the contact zones of the surrounding granitic rock. Stable isotope data of fissure filling calcites indicate that the influence of surface waters can be traced clearly down to a depth of about 50 m, but also at greater depths re-equilibration has occurred. Groundwater data from the site were not available. (orig.)

Cecal bacterial communities in wild Japanese rock ptarmigans and captive Svalbard rock ptarmigans.

Science.gov (United States)

Ushida, Kazunari; Segawa, Takahiro; Tsuchida, Sayaka; Murata, Koichi

2016-02-01

Preservation of indigenous gastrointestinal microbiota is deemed to be critical for successful captive breeding of endangered wild animals, yet its biology is poorly understood. Here, we investigated cecal bacterial communities in wild Japanese rock ptarmigans (Lagopus muta japonica) and compared them with those in Svalbard rock ptarmigans (L. m. hyperborea) in captivity. Ultra-deep sequencing of 16S rRNA gene indicated that the community structure of cecal microbiota in wild rock ptarmigans was remarkably different from that in captive Svalbard rock ptarmigans. Fundamental differences between bacterial communities in the two groups of birds were detected at the phylum level. Firmicutes, Actinobacteria, Bacteroidetes and Synergistetes were the major phyla detected in wild Japanese rock ptarmigans, whereas Firmicutes alone occupied more than 80% of abundance in captive Svalbard rock ptarmigans. Furthermore, unclassified genera of Coriobacteriaceae, Synergistaceae, Bacteroidaceae, Actinomycetaceae, Veillonellaceae and Clostridiales were the major taxa detected in wild individuals, whereas in zoo-reared birds, major genera were Ruminococcus, Blautia, Faecalibacterium and Akkermansia. Zoo-reared birds seemed to lack almost all rock ptarmigan-specific bacteria in their intestine, which may explain the relatively high rate of pathogenic infections affecting them. We show evidence that preservation and reconstitution of indigenous cecal microflora are critical for successful ex situ conservation and future re-introduction plan for the Japanese rock ptarmigan.

Rock engineering in Finland

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

Contains a large collection of short articles concerned with tunnels and underground caverns and their construction and use. The articles are grouped under the following headings: use of the subsurface space; water supply; waste water services; energy management (includes articles on power stations, district heating and oil storage and an article on coal storage); multipurpose tunnels; waste disposal; transport; shelters; sporting and recreational amenities located in rock caverns; storage facilities; industrial, laboratory, and service facilities; rock foundations; tourism and culture; utilization of rock masses; research on the disposal of nuclear waste; training and research in the field of rock engineering; site investigation techniques; design of structures in rock; construction; the environment and occupational safety; modern equipment technology; underground space in Helsinki.

Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.

Directory of Open Access Journals (Sweden)

Richard D Norris

Full Text Available The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice.

Rock stresses (Grimsel rock laboratory)

International Nuclear Information System (INIS)

Pahl, A.; Heusermann, S.; Braeuer, V.; Gloeggler, W.

1989-01-01

On the research and development project 'Rock Stress Measurements' the BGR has developed and tested several test devices and methods at GTS for use in boreholes at a depth of 200 m and has carried out rock mechanical and engineering geological investigations for the evaluation and interpretation of the stress measurements. The first time a computer for data processing was installed in the borehole together with the BGR-probe. Laboratory tests on hollow cylinders were made to study the stress-deformation behavior. To validate and to interprete the measurement results some test methods were modelled using the finite-element method. The dilatometer-tests yielded high values of Young's modulus, whereas laboratory tests showed lower values with a distinct deformation anisotropy. Stress measurements with the BGR-probe yielded horizontal stresses being higher than the theoretical overburden pressure and vertical stresses which agree well with the theoretical overburden pressure. These results are comparable to the results of the hydraulic fracturing tests, whereas stresses obtained with CSIR-triaxial cells are generally lower. The detailed geological mapping of the borehole indicated relationships between stress and geology. With regard to borehole depth different zones of rock structure joint frequency, joint orientation, and orientation of microfissures as well as stress magnitude, stress direction, and degree of deformation anisotropy could be distinguished. (orig./HP) [de

Agrin is a major heparan sulfate proteoglycan in the human glomerular basement membrane.

Science.gov (United States)

Groffen, A J; Ruegg, M A; Dijkman, H; van de Velden, T J; Buskens, C A; van den Born, J; Assmann, K J; Monnens, L A; Veerkamp, J H; van den Heuvel, L P

1998-01-01

Agrin is a heparan sulfate proteoglycan (HSPG) that is highly concentrated in the synaptic basal lamina at the neuromuscular junction (NMJ). Agrin-like immunoreactivity is also detected outside the NMJ. Here we show that agrin is a major HSPG component of the human glomerular basement membrane (GBM). This is in addition to perlecan, a previously characterized HSPG of basement membranes. Antibodies against agrin and against an unidentified GBM HSPG produced a strong staining of the GBM and the NMJ, different from that observed with anti-perlecan antibodies. In addition, anti-agrin antisera recognized purified GBM HSPG and competed with an anti-GBM HSPG monoclonal antibody in ELISA. Furthermore, both antibodies recognized a molecule that migrated in SDS-PAGE as a smear and had a molecular mass of approximately 200-210 kD after deglycosylation. In immunoelectron microscopy, agrin showed a linear distribution along the GBM and was present throughout the width of the GBM. This was again different from perlecan, which was exclusively present on the endothelial side of the GBM and was distributed in a nonlinear manner. Quantitative ELISA showed that, compared with perlecan, the agrin-like GBM HSPG showed a sixfold higher molarity in crude glomerular extract. These results show that agrin is a major component of the GBM, indicating that it may play a role in renal ultrafiltration and cell matrix interaction. (J Histochem Cytochem 46:19-27, 1998)

Review on the prevailing methods for the prediction of potential rock burst / rock spalling in tunnels

OpenAIRE

Panthi, Krishna Kanta

2017-01-01

Rock burst / rock spalling is among the prevailing stability challenges, which can be met while tunneling through hard rock mass. Especially, this is very relevant for the mountainous country like Norway where hard rock is dominating and many road, railway and hydropower tunnels have to be aligned deep into the mountain with steep valley slope topography. Tunnels passing beneath deep rock cover (overburden), in general, are subjected to high in-situ stresses. If the rock mass is relatively un...

Synthetic Rock Analogue for Permeability Studies of Rock Salt with Mudstone

Directory of Open Access Journals (Sweden)

Hongwu Yin

2017-09-01

Full Text Available Knowledge about the permeability of surrounding rock (salt rock and mudstone interlayer is an important topic, which acts as a key parameter to characterize the tightness of gas storage. The goal of experiments that test the permeability of gas storage facilities in rock salt is to develop a synthetic analogue to use as a permeability model. To address the permeability of a mudstone/salt layered and mixed rock mass in Jintan, Jiangsu Province, synthetic mixed and layered specimens using the mudstone and the salt were fabricated for permeability testing. Because of the gas “slippage effect”, test results are corrected by the Klinkenberg method, and the permeability of specimens is obtained by regression fitting. The results show that the permeability of synthetic pure rock salt is 6.9 × 10−20 m2, and its porosity is 3.8%. The permeability of synthetic mudstone rock is 2.97 × 10−18 m2, with a porosity 17.8%. These results are close to those obtained from intact natural specimens. We also find that with the same mudstone content, the permeability of mixed specimens is about 40% higher than for the layered specimens, and with an increase in the mudstone content, the Klinkenberg permeability increases for both types of specimens. The permeability and mudstone content have a strong exponential relationship. When the mudstone content is below 40%, the permeability increases only slightly with mudstone content, whereas above this threshold, the permeability increases rapidly with mudstone content. The results of the study are of use in the assessment of the tightness of natural gas storage facilities in mudstone-rich rock salt formations in China.

U-Th-PbT Monazite Gechronology in the South Carpathian Basement: Variscan Syn-Metamorphic Tectonic Stacking and Long-Lasting Post-Peak Decompressional Overprints

Science.gov (United States)

Săbău, G.; Negulescu, E.

2012-12-01

Dating metamorphic events appears to be unsatisfactorily addressed by most of the widely-employed and otherwise accurate and productive isotopic techniques, because the phases and systems investigated do not directly relate to the metamorphic events themselves. An adequate answer to this challenge is instead provided by microprobe-assisted chemical U-Th-PbT monazite geochronology, by its spatial resolution, truly in situ character and the possibility to reference analyses against well-defined textural environments and features, as well as a qualitative timeframe derived therefrom. Though chemical U-Th-PbT monazite geochronology is increasingly applied to seek answers ranging form a general characterization to fine details of the thermotectonic evolution of magmatic and metamorphic rocks, there are so far, unlike in the case of isotopic geochronological methods, no clearly defined standard analytical and data processing protocols. Two main reasons for this have to be mentioned, namely that chemical U-Th-PbT chronology is actually a proxy for isotopic geochronology, and the quantification of the errors and their propagation cannot be directly assessed because apparent ages are related to the measured element concentrations by an implicit function, the law of radioactive decay. Current approaches rely on treating calculated individual age values as primary data, a priori grouping of analyses supposed (and subsequently tested) to be coeval, and their statistical processing in order to obtain age values. An alternative approach we applied in basement units of the South Carpathians consists in an explicit approximation of the age formula and associated errors propagated from element concentrations to age values, and individual treatment of each age datum. The separation of the age clusters from the overall age spectrum of each sample was operated by tracing the variations of the normalized age gradient on the age spectrum sorted by increasing age values, and fine

'Mister Badger' Pushing Mars Rock

Science.gov (United States)

1976-01-01

Viking's soil sampler collector arm successfully pushed a rock on the surface of Mars during the afternoon of Friday, October 8. The irregular-shaped rock was pushed several inches by the Lander's collector arm, which displaced the rock to the left of its original position, leaving it cocked slightly upward. Photographs and other information verified the successful rock push. Photo at left shows the soil sampler's collector head pushing against the rock, named 'Mister Badger' by flight controllers. Photo at right shows the displaced rock and the depression whence it came. Part of the soil displacement was caused by the collector s backhoe. A soil sample will be taken from the site Monday night, October 11. It will then be delivered to Viking s organic chemistry instrument for a series of analyses during the next few weeks. The sample is being sought from beneath a rock because scientists believe that, if there are life forms on Mars, they may seek rocks as shelter from the Sun s intense ultraviolet radiation.

Source rock

Directory of Open Access Journals (Sweden)

Abubakr F. Makky

2014-03-01

Full Text Available West Beni Suef Concession is located at the western part of Beni Suef Basin which is a relatively under-explored basin and lies about 150 km south of Cairo. The major goal of this study is to evaluate the source rock by using different techniques as Rock-Eval pyrolysis, Vitrinite reflectance (%Ro, and well log data of some Cretaceous sequences including Abu Roash (E, F and G members, Kharita and Betty formations. The BasinMod 1D program is used in this study to construct the burial history and calculate the levels of thermal maturity of the Fayoum-1X well based on calibration of measured %Ro and Tmax against calculated %Ro model. The calculated Total Organic Carbon (TOC content from well log data compared with the measured TOC from the Rock-Eval pyrolysis in Fayoum-1X well is shown to match against the shale source rock but gives high values against the limestone source rock. For that, a new model is derived from well log data to calculate accurately the TOC content against the limestone source rock in the study area. The organic matter existing in Abu Roash (F member is fair to excellent and capable of generating a significant amount of hydrocarbons (oil prone produced from (mixed type I/II kerogen. The generation potential of kerogen in Abu Roash (E and G members and Betty formations is ranging from poor to fair, and generating hydrocarbons of oil and gas prone (mixed type II/III kerogen. Eventually, kerogen (type III of Kharita Formation has poor to very good generation potential and mainly produces gas. Thermal maturation of the measured %Ro, calculated %Ro model, Tmax and Production index (PI indicates that Abu Roash (F member exciting in the onset of oil generation, whereas Abu Roash (E and G members, Kharita and Betty formations entered the peak of oil generation.

Low enthalpy Na-chloride waters from the Lunigiana and Garfagnana grabens, Northern Apennines, Italy: Tracing fluid connections and basement interactions via chemical and isotopic compositions

Science.gov (United States)

Boschetti, Tiziano; Toscani, Lorenzo; Barbieri, Maurizio; Mucchino, Claudio; Marino, Tiziana

2017-12-01

The Na-Cl waters from NW Tuscany (central Italy) record similar water isotopic and major chemical compositions, which demonstrate their meteoric origin and interactions with Upper Triassic evaporites and the metamorphic units of the Paleozoic basement. Slight differences are found in the deep temperature-pressure conditions of the Lunigiana graben (39-42 °C/143-145 bar) and the Garfagnana graben (73-78 °C/250-256 bar). In particular, the thermal fluids outpouring from Garfagnana are probably related to a common deep reservoir or interconnected fluids. Their differences are mainly evidenced by strontium isotopic ratio data (87Sr/86Sr), which combined with previously published sulfur isotope ratios (34S/32S) demonstrate the involvement of vein barites in water-rock interactions. Most likely, these minerals formed during Upper Oligocene-Miocene tectogenesis due to the mixing of fluids from the Verrucano Group and Upper Triassic units. The results of this hydrogeochemical study of the deep Na-Cl fluids could better clarify the distribution of the Verrucano Group within this area and the related discrepancies in the stratigraphic interpretations of the Palaeozoic-Mesozoic transition. Furthermore, the possible presence of an interconnected reservoir could be used to help interpret data produced by the local geochemical monitoring of seismic activity.

Interim rock mass properties and conditions for analyses of a repository in crystalline rock

International Nuclear Information System (INIS)

Tammemagi, H.Y.; Chieslar, J.D.

1985-03-01

A summary of rock properties for generic crystalline rock is compiled from literature sources to provide the input data for analyses of a conceptual repository in crystalline rock. Frequency histograms, mean values and ranges of physical, mechanical, thermal, and thermomechanical properties, and the dependence of these properties on temperature are described. A description of the hydrogeologic properties of a crystalline rock mass and their dependence on depth is provided. In addition, the temperature gradients, mean annual surface temperature, and in situ stress conditions are summarized for the three regions of the United States currently under consideration to host a crystalline repository; i.e., the North Central, Northeastern, and Southeastern. Brief descriptions of the regional geology are also presented. Large-scale underground experiments in crystalline rock at Stripa, Sweden, and in Climax Stock in Nevada, are reviewed to assess whether the rock properties presented in this report are representative of in situ conditions. The suitability of each rock property and the sufficiency of its data base are described. 110 refs., 27 figs., 4 tabs

Intercellular deposits of basement membrane material in active human pituitary adenomas detected by immunostaining for laminin and electron microscopy

DEFF Research Database (Denmark)

Holck, S; Wewer, U M; Albrechtsen, R

1986-01-01

and one patient with Cushing's syndrome). Concurrently, at the ultrastructural level, bunches of basement membrane-like material intermingled between the adenoma cells were demonstrated in seven of these ten active adenomas. Furthermore, secretory granules were entrapped occasionally in this intercellular...

Pore-scale analysis of electrical properties in thinly bedded rock using digital rock physics

International Nuclear Information System (INIS)

Sun, Jianmeng; Zhao, Jianpeng; Liu, Xuefeng; Chen, Hui; Jiang, LiMing; Zhang, JinYan

2014-01-01

We investigated the electrical properties of laminated rock consist of macro-porous layers and micro-porous layers based on digital rock technology. Due to the bedding effect and anisotropy, traditional Archie equations cannot well describe the electrical behavior of laminated rock. The RI-Sw curve of laminated rock shows a nonlinear relationship. The RI-Sw curve can be divided into two linear segments with different saturation exponent. Laminated sand-shale sequences and laminated sands of different porosity or grain size will yield macroscopic electrical anisotropy. Numerical simulation and theoretical analysis lead to the conclusion that electrical anisotropy coefficient of laminated rock is a strong function of water saturation. The function curve can be divided into three segments by the turning point. Therefore, the electrical behavior of laminated rock should be considered in oil exploration and development. (paper)

Aeromagnetic and gravity investigations of the Coastal Area and Continental Shelf of Liberia, West Africa, and their relation to continental drift

Science.gov (United States)

Behrendt, John C.; Wotorson, Cletus S.

1970-01-01

An aeromagnetic survey has shown the existence of several basins in which magnetic basement depths are greater than 5 km on the continental shelf off Liberia. Magnetic diabase of 176 to 192 m.y. (Jurassic) in age intruding the Paleozoic (?) rocks and overlain by younger rocks onshore requires the distinction between “magnetic basement” and “basement.” Several lines of evidence suggest that the Paleozoic(?) rocks are less than 1 km thick; this implies that the diabase does not introduce a large error in depth-to-basement estimates. The dikes or their extrusive equivalents are traceable, on the basis of the magnetic data, beneath the younger sedimentary rock in the basins to the edge of the continental slope. The magnetic data also delineate a second zone of diabase dikes 90 km inland, parallel to the coast, which cross the entire country. The intrusion of the younger dikes probably coincides with rifting at the beginning of the separation of Africa and South America, and the associated magnetic anomaly zones appear to be parallel with and continuous into the anomaly bands in the Atlantic. A major northeast-trending break in the magnetic fabric intersects the coast near 9° W. and is associated with Eburnean age rocks (about 2000 m.y.) to the southeast as contrasted with Liberian-age rocks (about 2700 m.y.) to the northwest. Change in magnetic fabric direction inland from northeast to northwest in the coastal area allows recognition of a boundary between the Liberian-age rocks inland and Pan-African-age (about 550 m.y.) rocks in the coastal area northwest of about 9° 20'W. Sets of north-northwest-and west-northwest—trending faults of 1 to 2 km vertical displacement cut the Cretaceous sedimentary rocks onshore and can be traced into the offshore basins. Vertical displacements of several kilometers in the magnetic basement underlying the continental shelf suggest a pattern of block faulting all along the coast and continental shelf. Negative Bouguer

Research into basic rocks types

International Nuclear Information System (INIS)

1993-06-01

Teollisuuden Voima Oy (TVO) has carried out research into basic rock types in Finland. The research programme has been implemented in parallel with the preliminary site investigations for radioactive waste disposal in 1991-1993. The program contained two main objectives: firstly, to study the properties of the basic rock types and compare those with the other rock types under the investigation; secondly, to carry out an inventory of rock formations consisting of basic rock types and suitable in question for final disposal. A study of environmental factors important to know regarding the final disposal was made of formations identified. In total 159 formations exceeding the size of 4 km 2 were identified in the inventory. Of these formations 97 were intrusive igneous rock types and 62 originally extrusive volcanic rock types. Deposits consisting of ore minerals, industrial minerals or building stones related to these formations were studied. Environmental factors like natural resources, protected areas or potential for restrictions in land use were also studied

Nanoscale protein architecture of the kidney glomerular basement membrane

Science.gov (United States)

Suleiman, Hani; Zhang, Lei; Roth, Robyn; Heuser, John E; Miner, Jeffrey H; Shaw, Andrey S; Dani, Adish

2013-01-01

In multicellular organisms, proteins of the extracellular matrix (ECM) play structural and functional roles in essentially all organs, so understanding ECM protein organization in health and disease remains an important goal. Here, we used sub-diffraction resolution stochastic optical reconstruction microscopy (STORM) to resolve the in situ molecular organization of proteins within the kidney glomerular basement membrane (GBM), an essential mediator of glomerular ultrafiltration. Using multichannel STORM and STORM-electron microscopy correlation, we constructed a molecular reference frame that revealed a laminar organization of ECM proteins within the GBM. Separate analyses of domains near the N- and C-termini of agrin, laminin, and collagen IV in mouse and human GBM revealed a highly oriented macromolecular organization. Our analysis also revealed disruptions in this GBM architecture in a mouse model of Alport syndrome. These results provide the first nanoscopic glimpse into the organization of a complex ECM. DOI: http://dx.doi.org/10.7554/eLife.01149.001 PMID:24137544

FROM BASEMENTS AND FOUNDATIONS TO LEADING MODERN SCIENTIFIC SCHOOL

Directory of Open Access Journals (Sweden)

SEDIN V. L.

2016-10-01

Full Text Available Problem statement. Everything starts with the bases, both in philosophy and construction sense, Basements and Foundations Department was an essential part for the formation of Dnipropetrovsk Civil Engineering Institute. For its 85 years of existence, it was a reflection of development of the native institute later academy and the construction industry also in the whole. Thanks to a classical base and 40 years traditions of the scientific school, the department staff always did scientific basis and took part in the development of the state construction norms documents. Today, the department develops with considering the requirements of the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE, the science combining the engineering geology, studying the soil, soil mechanics, creating the model, designing of the foundation and subsurface structure with the use of the modern program complex, production technology works for foundation, monitoring of these works and the safety of the surrounding construction.

Evaluation of Rock Bolt Support for Polish Hard Rock Mines

Science.gov (United States)

Skrzypkowski, Krzysztof

2018-03-01

The article presents different types of rock bolt support used in Polish ore mining. Individual point resin and expansion rock bolt support were characterized. The roof classes for zinc and lead and copper ore mines were presented. Furthermore, in the article laboratory tests of point resin rock bolt support in a geometric scale of 1:1 with minimal fixing length of 0.6 m were made. Static testing of point resin rock bolt support were carried out on a laboratory test facility of Department of Underground Mining which simulate mine conditions for Polish ore and hard coal mining. Laboratory tests of point resin bolts were carried out, especially for the ZGH Bolesław, zinc and lead "Olkusz - Pomorzany" mine. The primary aim of the research was to check whether at the anchoring point length of 0.6 m by means of one and a half resin cartridge, the type bolt "Olkusz - 20A" is able to overcome the load.The second purpose of the study was to obtain load - displacement characteristic with determination of the elastic and plastic range of the bolt. For the best simulation of mine conditions the station steel cylinders with an external diameter of 0.1 m and a length of 0.6 m with a core of rock from the roof of the underground excavations were used.

Igneous Rocks

Science.gov (United States)

Doe, Bruce R.