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Godin, Laurent, Renaud Soucy La Roche, Lindsay Waffle, and Lyal B. Harris. "Influence of inherited Indian basement faults on the evolution of the Himalayan Orogen." Geological Society, London, Special Publications 481, no. 1 (April 13, 2018): 251–76. http://dx.doi.org/10.1144/sp481.4.
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AbstractIndian basement faults, which bound three orogen-perpendicular palaeotopographic ridges of Precambrian Indian basement south of the Himalaya, extend to the base of the Indian lithosphere and to the northern extent of the Indian lithosphere underneath Tibet. In the eastern Himalaya, the active orogen-perpendicular Yadong–Gulu graben is aligned with an earthquake-generating strike-slip fault in the high Himalaya. We argue that the graben results from crustal necking during reactivation of the underplated basement fault. In the central Himalaya, along-strike diachronous deformation and metamorphism within the Himalayan metamorphic core, as well as lateral ramps in the foreland thrust belt, spatially correspond to the Lucknow and Pokhara lineaments that bound the subsurface Faizabad Ridge in the Indian basement. Analogue centrifuge modelling confirms that offset along such deep-seated basement faults can affect the location, orientation and type of structures developed at various stages of orogenesis and suggests that it is mechanically feasible for strain to propagate through a melt-weakened mid-crust. We suggest that inherited Indian basement faults affect the ramp-flat geometry of the basal Main Himalayan Thrust, partition the Himalayan range into distinct zones, localize east–west extension resulting in the Tibetan graben and, ultimately, contribute to lateral variability in tectonic evolution along the orogen's strike.
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Gireesh, R., and D. K. Pandey. "Basement characteristics along South West Indian Margin." Petroleum Exploration and Development 41, no. 1 (February 2014): 68–73. http://dx.doi.org/10.1016/s1876-3804(14)60007-0.
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Bhattacharya, Nandini. "A ‘Basement’ Cinephilia. Indian Diaspora women watch Bollywood." South Asian Popular Culture 2, no. 2 (October 2004): 161–83. http://dx.doi.org/10.1080/1474668042000275734.
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Chauhan, Hiredya. "Geochemistry, Petrogenesis and Tectonic Setting of the Mafic Dykes from the Amgaon and Khairagarh Regions, Bastar Craton, Central Indian Shield: Constraints on the Precambrian Crustal Evolution." Journal of Atmospheric & Earth Science 6, no. 1 (December 31, 2022): 1–14. http://dx.doi.org/10.24966/aes-8780/100030.
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The presence of dominantly dykes, dyke swarms and sills along with the basement rocks indicate that the study area has undergone deep erosion exposing the basement rocks and these magmatic bodies (dykes, dyke swarms and sills) actually represent the plumbing system for the mantle derived melts, which contributed significantly to the Precambrian crustal evolution processes in the Central Indian shield
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Roy, A. B., and A. Kröner. "Single zircon evaporation ages constraining the growth of the Archaean Aravalli craton, northwestern Indian shield." Geological Magazine 133, no. 3 (May 1996): 333–42. http://dx.doi.org/10.1017/s0016756800009067.
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AbstractSingle grain 207Pb/206Pb zircon ages were determined for granitoids and gneisses which constitute the Archaean basement rocks of the Aravalli craton of Rajasthan, northwestern Indian Shield. The protolith ages for two gneisses, collected from east of Udaipur, are ˜3230 Ma and 2887 Ma respectively. The granitoids display an intrusive relationship with the gneisses and yielded ages ranging between 2666 Ma and 2620 Ma. These ages provide the basis for a geochronological model of evolution of the oldest basement of the Aravalli craton.
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Treloar, Peter J., Richard M. Palin, and Michael P. Searle. "Towards resolving the metamorphic enigma of the Indian Plate in the NW Himalaya of Pakistan." Geological Society, London, Special Publications 483, no. 1 (2019): 255–79. http://dx.doi.org/10.1144/sp483-2019-22.
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AbstractThe Pakistan part of the Himalaya has major differences in tectonic evolution compared with the main Himalayan range to the east of the Nanga Parbat syntaxis. There is no equivalent of the Tethyan Himalaya sedimentary sequence south of the Indus–Tsangpo suture zone, no equivalent of the Main Central Thrust, and no Miocene metamorphism and leucogranite emplacement. The Kohistan Arc was thrust southward onto the leading edge of continental India. All rocks exposed to the south of the arc in the footwall of the Main Mantle Thrust preserve metamorphic histories. However, these do not all record Cenozoic metamorphism. Basement rocks record Paleo-Proterozoic metamorphism with no Cenozoic heating; Neo-Proterozoic through Cambrian sediments record Ordovician ages for peak kyanite and sillimanite grade metamorphism, although Ar–Ar data indicate a Cenozoic thermal imprint which did not reset the peak metamorphic assemblages. The only rocks that clearly record Cenozoic metamorphism are Upper Paleozoic through Mesozoic cover sediments. Thermobarometric data suggest burial of these rocks along a clockwise pressure–temperature path to pressure–temperature conditions of c. 10–11 kbar and c. 700°C. Resolving this enigma is challenging but implies downward heating into the Indian plate, coupled with later development of unconformity parallel shear zones that detach Upper Paleozoic–Cenozoic cover rocks from Neoproterozoic to Paleozoic basement rocks and also detach those rocks from the Paleoproterozoic basement.
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Singh, Kamal Jeet, Anil Chandra, and Shaila Chandra. "Evaluation of earliest Permian flora of India and its equivalents in other Gondwana continents." Journal of Palaeosciences 54, no. (1-3) (December 31, 2005): 107–13. http://dx.doi.org/10.54991/jop.2005.73.
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The Talchir Formation occurs at the base of the Indian Gondwana sequence resting directly on the Precambrian basement and is conformably overlain by the coal bearing Damuda Group. It is a treasure trove of plant fossils and holds clue to the origin and subsequent rise of Glossopteris flora. Mega and palynofossils of the Talchir Formation reported from various basins of peninsular India are reviewed in the light of new researches. A comparative study of homotaxial flora from other Gondwana continents indicates uniformity and similarity in plant types at the generic level. The flora reconfirms an Early Permian age equivalent to Asselian-Sakmarian for the Talchir Formation.
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Davis, Richard H. "Indian Art Objects as Loot." Journal of Asian Studies 52, no. 1 (February 1993): 22–48. http://dx.doi.org/10.2307/2059143.
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Let us imagine a graceful bronze image of Dancing Śiva before us. It was perhaps created by a Cola artist in eleventh-century Tamilnad to be installed in a temple to receive offerings of worship, and to parade around the town in a ceremonial palanquin on festival days. From there, this image might have followed any of several paths to stand before us now in a North American museum. Perhaps it was buried under a banyan tree in the fourteenth century when invading Islamic armies, feared for their iconoclasm, marched through the Kaveri delta on their way to Madurai. It could have been disinterred in the nineteenth century, during British rule, by a Tamil workman on a road crew, who showed it to the civil engineer, who brought it to the attention of the District Collector, who passed it on to the Director of Archaeology. In the twentieth century, perhaps, when an international market developed for such objects, it might have ended up in an auction room, a cosmic dance sold to the highest bidder. Or a government expert on culture might have selected it, after its long hibernation in the basement storehouse of its temple, as an image worthy to travel abroad as an ambassador of independent India in the international diplomatics of traveling exhibitions.
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Shah, Siddharth M., and Drushi D. Patel. "COL4A1 mutation in an Indian child presenting as ‘Cerebral Palsy’ mimic." Indian Journal of Radiology and Imaging 30, no. 04 (October 2020): 500–503. http://dx.doi.org/10.4103/ijri.ijri_274_20.
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AbstractThe COL4A1 gene (COL4A1) plays an important role in vascular basement membrane function and pathogenic mutations have been reported in mice and humans. The gene is expressed mainly in the human brain, eyes and kidneys. Pathogenic mutations result in a vast array of manifestations that can present throughout life including the foetal period. We present a case of an 11-year-old girl with right hemiparesis, congenital cataracts, epilepsy and magnetic resonance imaging (MRI) brain findings with a pathogenic COL4A1 mutation. Many of her clinical features are similar to those of a non-genetic cause of cerebral palsy highlighting the difficulties and delays in making this genetic diagnosis.
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Khan, Majid, Yike Liu, Asam Farid, and Muhammad Owais. "Characterizing Seismo-stratigraphic and Structural Framework of Late Cretaceous-Recent succession of offshore Indus Pakistan." Open Geosciences 10, no. 1 (June 11, 2018): 174–91. http://dx.doi.org/10.1515/geo-2018-0014.
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Abstract Regional seismic reflection profiles and deep exploratory wells have been used to characterize the subsurface structural trends and seismo-stratigraphic architecture of the sedimentary successions in offshore Indus Pakistan. To improve the data quality, we have reprocessed the seismic data by applying signal processing scheme to enhance the reflection continuity for obtaining better results. Synthetic seismograms have been used to identify and tie the seismic reflections to the well data. The seismic data revealed tectonically controlled, distinct episodes of normal faulting representing rifting during Mesozoic and transpression at Late Eocene time. A SW-NE oriented anticlinal type push up structure is observed resulted from the basement reactivation and recent transpression along Indian Plate margin. The structural growth of this particular pushup geometry was computed. Six mappable seismic sequences have been identified on seismic records. In general, geological formations are at shallow depths towards northwest due to basement blocks uplift. A paleoshelf is also identified on seismic records overlain by Cretaceous sediments, which is indicative of Indian-African Plates rifting at Jurassic time. The seismic interpretation reveals that the structural styles and stratigraphy of the region were significantly affected by the northward drift of the Indian Plate, post-rifting, and sedimentation along its western margin during Middle Cenozoic. A considerable structural growth along the push up geometry indicates present day transpression in the margin sediments. The present comprehensive interpretation can help in understanding the complex structures in passive continental margins worldwide that display similar characteristics but are considered to be dominated by rifting and drifting tectonics.
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Barr, Sandra M., Robert P. Raeside, and Otto van Breemen. "Grenvillian basement in the northern Cape Breton Highlands, Nova Scotia." Canadian Journal of Earth Sciences 24, no. 5 (May 1, 1987): 992–97. http://dx.doi.org/10.1139/e87-096.
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The northernmost Cape Breton Highlands are underlain by the Blair River Complex, a distinctive assemblage of basement rocks including felsic and mafic gneisses, foliated gabbroic to granitic rocks, anorthosite, and foliated and unfoliated varieties of syenite. Major faults and mylonite zones separate the complex from schists, gneisses, and granitoid rocks typical of the rest of the Cape Breton Highlands. U–Pb dating of zircon from the Lowland Brook syenite of the Blair River Complex indicates a metamorphic age of [Formula: see text] and an igneous age of 1100–1500 Ma. These ages and the distinctive rock assemblage allow the Blair River Complex to be correlated with the Grenvillian rocks in the Long Range Inlier and Indian Head Range Complex of western Newfoundland. This is the first confirmed report of Grenvillian basement in Cape Breton Island, and it places new constraints on correlations between Newfoundland and the northern mainland Appalachians.
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Saravanavel, J., and S. M. Ramasamy. "GIS based 3D visualization of subsurface and surface lineaments / faults and their geological significance, northern tamil nadu, India." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (November 28, 2014): 469–76. http://dx.doi.org/10.5194/isprsarchives-xl-8-469-2014.
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The study area falls in the southern part of the Indian Peninsular comprising hard crystalline rocks of Archaeozoic and Proterozoic Era. In the present study, the GIS based 3D visualizations of gravity, magnetic, resistivity and topographic datasets were made and therefrom the basement lineaments, shallow subsurface lineaments and surface lineaments/faults were interpreted. These lineaments were classified as category-1 i.e. exclusively surface lineaments, category-2 i.e. surface lineaments having connectivity with shallow subsurface lineaments and category-3 i.e. surface lineaments having connectivity with shallow subsurface lineaments and basement lineaments. These three classified lineaments were analyzed in conjunction with known mineral occurrences and historical seismicity of the study area in GIS environment. The study revealed that the category-3 NNE-SSW to NE-SW lineaments have greater control over the mineral occurrences and the N-S, NNE-SSW and NE-SW, faults/lineaments control the seismicities in the study area.
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Polve, Mireille, Rene C. Maury, Philippe Vidal, Bambang Priadi, Herve Bellon, Rubini Soeria-Atmadja, Jean-Louis Joron, and Joseph Cotten. "Melting of lower continental crust in a young post-collision setting; a geochemical study of Plio-Quaternary acidic magmatism from central Sulawesi (Indonesia)." Bulletin de la Société Géologique de France 172, no. 3 (May 1, 2001): 333–42. http://dx.doi.org/10.2113/172.3.333.
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Abstract Acidic potassic calc-alkaline (CAK) magmas have been emplaced in the central part of the western arm of Sulawesi from 6.5 to 0.6 Ma, mostly as peraluminous dacites, rhyolites and granites. They overlay or crosscut a high-grade metamorphic basement including lower crustal garnet peridotites and granulites, the latter showing evidences for incipient melting during rapid uplift. Major and trace element data coupled with a Sr, Nd and Pb isotopic study of the CAK magmas and their lower crustal basement rocks demonstrate that they share a number of common features, including radiogenic Sr and Pb and unradiogenic Nd signatures, consistent with those of Australian granulites and Indian Ocean sediments. We propose that the CAK magmas derived from the anatexis of lower crustal rocks of Australian origin (the Banggai-Sula microcontinent) during the phase of uplift which followed their collision with the Sundaland margin (the western arm of Sulawesi) during the Middle Miocene, and possibly the breakoff of the subducted Molucca Sea slab.
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Shukla, Matsyendra Kumar, Piyal Halder, Kamlesh Kumar, and Anupam Sharma. "Fluid–rock interaction in the basement granitoids: A plausible answer to recurring seismicity." Journal of Palaeosciences 72, no. 1 (July 14, 2023): 1–8. http://dx.doi.org/10.54991/jop.2023.1853.
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The Koyna–Warna Seismogenic Region in the western part of the Indian Subcontinent has been recognized as one of the most significant sites of Reservoir–Triggered–Seismicity (RTS) during the last five decades. The basement granitoids, overlain by the porous and vesicular Deccan Trap basalt, contain numerous interconnecting fractures which act as the ascending and descending pathways of fluid flow. As a result of this fluid flow along fractures, the host rock has been subjected to significant chemical alteration along with the subsequent formation of some new minerals at the expense of a few other pre–existing mineral phases. Mesoscopic observations followed by Optical microscopy in the core samples of the basement rocks upto 1.5 km depth retrieved from the borehole KBH1 near Rasati (about 4.7 km from the Koyna Dam) have revealed the presence of chlorite and the precipitation of calcite, whereas the bulk mineralogical XRD has reaffirmed the presence of chlorite, calcite along with illite at a certain depth. This entire secondary mineral assemblage resembles the propylitic kind of hydrothermal alteration at temperatures < 350°C under acid–to–neutral solution conditions and also indicates water channelization up to the deeper level in the basement granitoids (>1.5 km). In addition, the presence of the hydrophilic clay minerals along fault and fracture zones may be responsible for triggering the seismicity in the Koyna Seismogenic Region as their absorption of water reduces the shear strength of faults and their low frictional strength accelerates the fault weakening process causing the generation of slip surfaces. Thus, in addition to several seismotectonic features, fault geometry and existing stress pattern, the clay mineralisation along the pre–existing faults and fractures of the basement rocks may also be a factor behind the recurring seismicity in this region.
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Ravi Kumar, Sistla. "Crustal deformation of the Central Indian Ocean, south of Sri Lanka as inferred from gravity and magnetic data." Geology, Geophysics and Environment 48, no. 2 (July 5, 2022): 89–110. http://dx.doi.org/10.7494/geol.2022.48.2.89.
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Bathymetry, gravity, and magnetic data across the Central Indian Ocean Basin (CIOB) along a WE track between 5°N to 1°N latitudes and 77°E to 90°E longitudes are used to identify crustal deformation due to tectonic features such as the Comorin Ridge, 85°E ridge, Ninety East Ridge, and major fracture zones. The tectonic features were interpreted along the North Central Indian Ocean using 2D gravity modelling to understand the origin and tectonic activity of the subsurface features. The Comorin Ridge is coupled with gravity anomalies with small amplitude varying 25–30 mGal in comparison with the ridge relief which suggests that the ridge is compensated at deeper depths. The focus of the present study is to prepare a reasonable crustal model of the Central Indian Ocean using gravity and magnetic data. The crustal depths of the Central Indian Ocean Basin (CIOB) determined from gravity data using the spectral method are compared with the 2D gravity modelling results. It has been observed that the crustal depths obtained from the Spectral method are in good correlation with results obtained from 2D gravity modelling. The average basement depths for the profiles were obtained as ~5 km and perhaps deviated approximately 1–2 km from the mean. In the case of curie isotherm, the crustal depths vary 9–12 km for all magnetic profiles which may indicate deformation.
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Jnawali, Bharat Mani. "Tectonic setting of the Nepal Himalaya and its potential for hydrocarbon exploration." Journal of Nepal Geological Society 39 (September 25, 2009): 77–84. http://dx.doi.org/10.3126/jngs.v39i0.31490.
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Nepal lies at the collision zone between the Indian subcontinent and the Tibetan Plateau of the Eurasian continent. It is made up of enormous tectonic stacking of sedimentary and metamorphic rocks with granite intrusions that resulted from the collision and under-plating of the Indian Craton with the Lhasa block of Tibet. The five major tectonic zones separated from each other by thrust contacts from south to north are the Terai, Siwalik or Sub Himalaya, Lesser Himalaya, Higher Himalaya and Tibetan Tethys. On the northern margin of the Indian subcontinent, foreland sedimentary basins began to develop immediately after the terminal collision between the northward drifting Indian Plate and relatively passive Eurasian Plate in Late Eocene time. The southern part of Nepal known as the Terai and Siwalik foothill, lies in the northern margin of the Ganga Basin and Purnea Basin that extend from India. Such basins with thick accumulation of sediments are considered as the potential area for petroleum exploration.
Regional scale seismic reflection, gravity and magnetic data combined with surface mapping and basin analysis have established the subsurface framework of southern Nepal. Geological settings potential for hydrocarbon prospects recognized in Nepal include structural traps related to normal faulting involving pre-Siwalik formation and thrusting involving Siwaliks, structural traps associated with frontal blind thrusts, anticlines and thrust-faults, basement controlled structures and stratigraphic pinchouts.
Drilling data consists of only one well drilled in the eastern part of Nepal. Oil and gas seeps have been observed in Dailekh area emanating through deep faults. Geochemical analyses of these seep samples indicate that these oil and gas have geologic origin from mature source rocks. Various outcrop samples from different parts of the country have been found rich in organic carbon. Source-rock maturity basin modeling constructed for various sections indicates that the level of thermal maturity is within oil and gas generating window. The Potwar Basin to the west in Pakistan and Assam Basin to the east in India having similar geologic setting to that of Nepal are producing oil and gas for a long time. In the Indo-Gangetic Plain across the border on Indian side, many deep wells have recorded the presence of gas and high content of organic carbon. Assessment of the available data acquired so far indicate that there is a fairly good possibility of discovering petroleum resource in Nepal.
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Ginting, Jody Martin, and Vivianty Vivianty. "Analysis of Retaining Wall Calculations in the Pollux Meisterstadt Habibie Batam Project with Indian Standard." Civilla : Jurnal Teknik Sipil Universitas Islam Lamongan 7, no. 2 (September 15, 2022): 183. http://dx.doi.org/10.30736/cvl.v7i2.899.
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Soil retaining wall infrastructure is an important supporting structure in preventing soil cladding. This infrastructure has as much in the city as a basement development. The design of the infrastructure requires effective and efficient standardization and with the difference in standardization of other countries, it does not hurt to try to use foreign standards to find out the difference. This research aims to analyze the moment of upsizing, shearing force with Indian Standard where data obtained from the field. The methods that have been used for this analysis are observational studies, literatures and interviews with consultants. In this research, the author produced calculations by the author regarding the reinforcements used in the field with SNI and the results of comparisons calculated by the author with the Indian Standard. This analyst started from calculating the moment of scrolling, the sliding force that will occur on the retaining wall then from the moment and we got the required reinforcement on the retaining wall. With existing loads and factors used according to Indian standards, especially in IS 456-2000. The resulting report on the results of comparison and the cause of the need for reinforcements realized with those that have been taken into account.
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SRIVASTAVA, DEEPAK C. "Geometrical similarity in successively developed folds and sheath folds in the basement rocks of the northwestern Indian Shield." Geological Magazine 148, no. 1 (August 20, 2010): 171–82. http://dx.doi.org/10.1017/s0016756810000610.
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AbstractAn intensely deformed gneiss–migmatite terrane and a relatively undeformed granulite–granitoid terrane constitute the bulk of Precambrian basement in the northwestern Indian Shield. This article traces the structural evolution in the gneiss–migmatite terrane, where traditional methods of structural analysis are difficult to apply, and shows how successively developed folds can assume identical geometry and orientation at an advanced stage of progressive ductile shearing. The gneiss–migmatite terrane exemplifies a regional-scale ductile shear zone that preserves the history of polyphase folding and sheath folding. Geometrical similarity between individual/domain-scale sheath folds and mesoscopic/regional-scale folds implies that sheath folding is common at all scales in the gneiss–migmatite terrane. As the mylonite foliation that traces successive folds is curviplanar, the successively initiated hinge lines were curvilinear from their inception in the shear zone. At the advanced stage of ductile shearing, the hinge line curvatures were accentuated due to their rotation towards subvertically directed maximum stretching (X), and variably oriented fold axial planes were brought into approximate parallelism with the upright principal plane (XY) of the bulk strain ellipsoid. Eventually all the folds, irrespective of their relative order of development, became strongly non-cylindrical, extremely tight, isoclinal and approximately co-planar with respect to each other. It is due to the above geometrical modifications during ductile shearing that folds, irrespective of their order of development, now appear identical with respect to isoclinal geometry, axial plane orientation and hinge line curvilinearity. Evidence from the fold orientations, the deformed lineation patterns and the sheath fold geometry suggest that the shearing occurred in a general shear type of bulk strain, and NNW–SSE-directed subhorizontal compression resulted in subvertically directed stretching in the gneiss–migmatite terrane.
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Trivedi, Premila, Juha Risteli, Leila Risteli, M. Stuart Tanner, Sheila Bhave, Anand N. Pandit, and Alex P. Mowat. "Serum type III procollagen and basement membrane proteins as noninvasive markers of hepatic pathology in Indian childhood cirrhosis." Hepatology 7, no. 6 (November 1987): 1249–53. http://dx.doi.org/10.1002/hep.1840070612.
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SCHAMING, MARC, and YAIR ROTSTEIN. "Basement reflectors in the Kerguelen Plateau, south Indian Ocean: Indications for the structure and early history of the plateau." Geological Society of America Bulletin 102, no. 5 (May 1990): 580–92. http://dx.doi.org/10.1130/0016-7606(1990)102<0580:britkp>2.3.co;2.
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Maashari, Raghda Saeed Al, Al Mahmood Noaf S, and Saleem Tausif. "Vesiculo-Bullous Eruption Following COVID Vaccination." Saudi Journal of Medicine 7, no. 9 (September 23, 2022): 501–4. http://dx.doi.org/10.36348/sjm.2022.v07i09.007.
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Bullous pemphigoid (BP) is an autoimmune sub-epidermal bullous disorder with a complex etiopathogenesis, predominately affecting the elderly. We report a case of COVID vaccination- induced BP, in a 30-year-old previously healthy Indian male who presented with a 1month history of itchy generalized vesiculo-bullous eruption that developed 3 days after receiving the first dose of the COVID vaccination. Histological examination and direct immunofluorescence study showed a sub-epidermal blister with a dermal inflammatory infiltrate and linear epidermal staining of IgG and C3 along the basement membrane zone in an n-serrated pattern. Treatment with oral prednisolone and oral doxycycline resulted in significant improvement in his condition. To our knowledge, there are limited case reports to date particularly in the Middle-East, which describe BP triggered by COVID vaccination.
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Marie, Pettenati, Picot-Colbeaux Géraldine, Thiéry Dominique, Boisson Alexandre, Alazard Marina, Perrin Jérome, Dewandel Benoît, Maréchal Jean-Christophe, Ahmed Shakeel, and Kloppmann Wolfram. "Water Quality Evolution During Managed Aquifer Recharge (MAR) in Indian Crystalline Basement Aquifers: Reactive Transport Modeling in the Critical Zone." Procedia Earth and Planetary Science 10 (2014): 82–87. http://dx.doi.org/10.1016/j.proeps.2014.08.016.
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RAVI KUMAR, Sistla, and Shaik Kareemunnisa BEGUM. "Interpretation of gravity and magnetic data in the Central Indian Ocean." Contributions to Geophysics and Geodesy 52, no. 3 (September 30, 2022): 359–93. http://dx.doi.org/10.31577/congeo.2022.52.3.2.
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The crustal deformation in the Central Indian Ocean is due to major undulations of the oceanic crust, longitudinal fracture zones, and sea-floor topography. The gravity and magnetic data along with six long profiles across the Central Indian Ocean Basin on W–E tracks between 6°S – 1°S latitudes and 77°E – 90°E longitudes are used to study this deformation. It has been observed that the crustal depths obtained from spectral analysis of gravity and magnetic data are in good agreement with 2D forward gravity modelling results which supports seismic results. The computed seismic velocities for the sediments are 2.0 – 5.7 km/s and 6.1 – 7.7 km/s for the oceanic igneous layer and 8.3 – 8.5 km/s for the oceanic upper mantle are used to determine the densities of oceanic crust with the velocity-density relationship. The average basement depths for all the gravity and magnetic profiles are obtained as ~5 km with deviations of about 1 – 2 km from the mean and for the deeper marker, the crustal depths vary from 9 km to 12 km. In the case of curie isotherm, the crustal depths vary from 9 km to 12 km for all magnetic profiles which may indicate deformation. The crustal top depths vary in the range of 3.5 – 8 km (3.2 – 6 km) and the bottom depth varies in the range of 8.2 – 13.5 km (8.5 – 13 km) for magnetic field anomaly data using the spectral method (the Werner method). The crustal top depths vary in the range of 3.6 – 6.5 km and the bottom depth varies in the range of 7.5 – 11.5 km for free-air anomaly data using the spectral method. The above depths are almost correlated with interpreted 2D gravity modelling and available Seismic results.
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O'Brien, Patrick J. "Eclogites and other high-pressure rocks in the Himalaya: a review." Geological Society, London, Special Publications 483, no. 1 (December 3, 2018): 183–213. http://dx.doi.org/10.1144/sp483.13.
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AbstractHimalayan high-pressure metamorphic rocks are restricted to three environments: the suture zone; close to the suture zone; and (mostly) far (>100 km) from the suture zone. In the NW Himalaya and South Tibet, Cretaceous-age blueschists (glaucophane-, lawsonite- or carpholite-bearing schists) formed in the accretionary wedge of the subducting Neo-Tethys. Microdiamond and associated phases from suture-zone ophiolites (Luobusa and Nidar) are, however, unrelated to Himalayan subduction–collision processes. Deeply subducted and rapidly exhumed Indian Plate basement and cover rocks directly adjacent to the suture zone enclose eclogites of Eocene age, some coesite-bearing (Kaghan/Neelum and Tso Morari), formed from Permian Panjal Trap, continental-type, basaltic magmatic rocks. Eclogites with a granulite-facies overprint, yielding Oligocene–Miocene ages, occur in the anatectic cordierite ± sillimanite-grade Indian Plate mostly significantly south of the suture zone (Kharta/Ama Drime/Arun, north Sikkim and NW Bhutan) but also directly at the suture zone at Namche Barwa. The sequence carpholite-, coesite-, kyanite- and cordierite-bearing rocks of these different units demonstrates the transition from oceanic subduction to continental collision via continental subduction. The granulitized eclogites in anatectic gneisses preserve evidence of former thick crust as in other wide hot orogens, such as the European Variscides.
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Chatterjee, Sankar, and Dhiraj Kumar Rudra. "Shiva impact event and its implications for Deccan Volcanism and Dinosaur Extinction." Journal of Palaeosciences 57, no. (1-3) (December 31, 2008): 235–50. http://dx.doi.org/10.54991/jop.2008.241.
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We have identified a buried 500 km diameter Shiva structure on the western shelf of India as a possible impact crater that formed at the Cretaceous-Tertiary (KT) boundary time. The location of the Shiva crater was initially suggested between India-Seychelles block, when Seychelles was part of the Indian Plate at its western margin around 65 Ma. This work refines previous interpretations of the structure, morphology and the extent of the Shiva crater, which now appears to be located entirely on the Mumbai Offshore Basin encircling the Bombay High area. The Shiva crater is largely submerged on the passive western continental shelf and is buried by 7 km thick strata of post-impact Cenozoic sediments. It is the largest impact crater known on Earth, about 500 km diameter and is a rich source of oil and gas. It has the morphology of a complex peak ring structure with a multiring basin configuration, thus providing an ideal structural trap for petroleum entrapment. Four different ring structures have been identified, where the inner peak ring represents the central uplift of the Bombay High area with a core of Neoproterozoic granite basement. Inside the peak ring, a series of rugged mountainous peaks tower more than 7 km above the basin floor. We speculate that the Shiva bolide (~40 km diameter) crashed obliquely on the western continental shelf of India around 65 Ma, excavating the crater, shattering the lithosphere, initiated the rifting between India and the Seychelles and triggered the acceleration of the Indian Plate northward. The Cretaceous-Tertiary boundary sections of India have yielded several proximal ejecta components linked to the Shiva event such as shocked quartz, spherules and glass shards and iridium-rich alkaline melt rocks. Other cosmic signatures at the KT boundary of India from the vapourized meteorite include iridium anomaly, natural fullerenes, nickelrich spinels and magnetic nanoparticles. Although the Reunion hotspot responsible for Deccan eruption was close to the Shiva crater in time and space, impact did not trigger the hotspot because the first phase of the Deccan volcanism preceded the Shiva impact by 400,000 years or more. Two large impacts such as Shiva and Chicxulub in quick succession on the antipodal position, in concert with Deccan eruption, would have devastating effects globally leading to climatic and environmental calamity that wiped out the dinosaurs and many other organisms at the KT boundary.
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Palmer, Sarah E., John W. F. Waldron, and D. M. Skilliter. "Post-Taconian shortening, inversion and strike slip in the Stephenville area, western Newfoundland Appalachians." Canadian Journal of Earth Sciences 39, no. 9 (September 1, 2002): 1393–410. http://dx.doi.org/10.1139/e02-041.
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Deformed terrigenous and carbonate sedimentary rocks representing the early Paleozoic Laurentian continental margin form a series of elongate, fault-bounded blocks that plunge north beneath the Humber Arm Allochthon in the Stephenville area, west Newfoundland Appalachians. The continental shelf succession was folded and thrust-faulted after emplacement of the Humber Arm Allochthon. In the west of the area, Table Mountain is cut by a "pop-up" structure bounded by downward-converging reverse faults. Structures at the east margin of Table Mountain indicate both dextral and reverse slip. The Phillips Brook Structure, farther east, contains multiple, fault-bounded carbonate slices; one slice, carried by the West Blanche Brook fault, is thrust over the Humber Arm Allochthon. The western edge of the Indian Head massif, consisting of Grenville basement, is also a thrust contact. These reverse faults and thrusts, which cut the carbonate succession and postdate emplacement of the Humber Arm Allochthon, are in turn overprinted by structures formed during dextral strike-slip motion. Unconformable Early Carboniferous cover postdates most of the deformation. Cross-sections indicate shortening of a few kilometres, and basement was clearly involved in the deformation. The Port au Port Peninsula, immediately to the west, records a history of Acadian inversion of Taconian basins. The prevalence of pop-up structures and mappable variations within the stratigraphic units forming the top of the carbonate succession indicate that a complex geometry of Taconian horsts and grabens was inverted during post-Taconian (?Acadian) shortening and dextral strike-slip motion. These relationships suggest a variety of attractive targets in petroleum exploration.
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Bielenberg, U., W. Burns, W. Clark Lambert, R. A. Schwartz, and E. Marquet. "Dermatopathia Pigmentosa Reticularis." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 3 (August 12, 1990): 236–37. http://dx.doi.org/10.1017/s0424820100158728.
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Dermatopathia pigmentosa reticularis (DPR) is a reticulate pigmentary disorder of as yet unclear inheritance that was first described in 1958. Since then only an additional eight cases have been reported, all in the European literature. To our knowledge, this is the first case from the United States of America and the first with an ultrastructural study.The patient is a 44-year-old man of mixed Black, Hispanic and American Indian descent with generalized, variably pigmented skin over the entire body present since birth.A punch biopsy of pigmented forearm skin was taken for light microscopy which demonstrated hyperkeratosis, an intact granular layer, and epidermal atrophy with focal liquefaction degeneration of the basal cell layer. The dermis showed pigment incontinence. Direct immunofluorescence was negative for immunoglobulins and complement at the basement membrane zone. A second skin biopsy of an elbow plaque showed the above changes except for the alteration of the basal layer.
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Bai, Ling, Simon L. Klemperer, James Mori, Marianne S. Karplus, Lin Ding, Hongbing Liu, Guohui Li, Bowen Song, and Sanjev Dhakal. "Lateral variation of the Main Himalayan Thrust controls the rupture length of the 2015 Gorkha earthquake in Nepal." Science Advances 5, no. 6 (June 2019): eaav0723. http://dx.doi.org/10.1126/sciadv.aav0723.
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The Himalaya orogenic belt produces frequent large earthquakes that affect population centers along a length of over 2500 km. The 2015 Gorkha, Nepal earthquake (Mw 7.8) ruptured the Main Himalayan Thrust (MHT) and allows direct measurements of the behavior of the continental collision zone. We study the MHT using seismic waveforms recorded by local stations that completely cover the aftershock zone. The MHT exhibits clear lateral variation along geologic strike, with the Lesser Himalayan ramp having moderate dip on the MHT beneath the mainshock area and a flatter and deeper MHT beneath the eastern end of the aftershock zone. East of the aftershock zone, seismic wave speed increases at MHT depths, perhaps due to subduction of an Indian basement ridge. A similar magnitude wave speed change occurs at the western end of the aftershock zone. These gross morphological structures of the MHT controlled the rupture length of the Gorkha earthquake.
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Godin, Laurent, and Lyal B. Harris. "Tracking basement cross-strike discontinuities in the Indian crust beneath the Himalayan orogen using gravity data – relationship to upper crustal faults." Geophysical Journal International 198, no. 1 (May 2, 2014): 198–215. http://dx.doi.org/10.1093/gji/ggu131.
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Ameen, S. M. Mahbubul, Simon A. Wilde, Md Zafrul Kabir, Eunuse Akon, Khalil R. Chowdhury, and Md Sharif Hossain Khan. "Paleoproterozoic granitoids in the basement of Bangladesh: A piece of the Indian shield or an exotic fragment of the Gondwana jigsaw?" Gondwana Research 12, no. 4 (November 2007): 380–87. http://dx.doi.org/10.1016/j.gr.2007.02.001.
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Gobeil, Jean-Philippe, Georgia Pe-Piper, and David JW Piper. "The West Indian Road pit, central Nova Scotia: key to the Early Cretaceous Chaswood Formation." Canadian Journal of Earth Sciences 43, no. 3 (March 1, 2006): 391–403. http://dx.doi.org/10.1139/e06-032.
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The West Indian Road pit is the only large outcrop in Nova Scotia of the Chaswood Formation, the terrestrial equivalent of the offshore Missisauga and Logan Canyon formations. It provides outcrop information on sedimentology, gravel petrology, and structures for a formation that is otherwise known from a few small overgrown pits and from boreholes. The Chaswood Formation in the pit is > 60 m thick and consists principally of sorted sand and gravel with three thinner clay units. Successions of sedimentary structures indicate deposition from a coarse-bedload river flowing to the east-southeast. Gravel consists principally of vein quartz, quartz arenite, and subarkose, together with minor igneous lithologies that can be matched to sources in the Cobequid Highlands to the north. Quartz arenite and subarkose appear derived from Carboniferous Horton Group. Single-crystal 40Ar/39Ar dates of detrital muscovite are a little older than the muscovite ages for the South Mountain batholith, interpreted to mean that the muscovite is second cycle from the Horton Group, which records the earliest unroofing of the batholith. The Chaswood Formation accumulated during progressive tectonic deformation along NNE-trending strike-slip faults in basement rocks, resulting in syn-sedimentary faulting and local unconformities. Sedimentation kept pace with the creation of accommodation. Unrelated younger deformation folded the Chaswood Formation at the pit into an eastwest-trending syncline. The Early Cretaceous paleogeography of the Maritime Provinces is interpreted to have consisted of fault-bound horsts shedding coarse detritus surrounded by an interconnected series of basins that accumulated fluvial sands and gravels and overbank muds with well-developed paleosols.
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Rajesh, S., and T. J. Majumdar. "Effects of Ninetyeast Ridge magmatism and pre India-Eurasia collision dynamics on basement and crust-lithospheric structures of the Northeastern Indian Ocean." Journal of the Geological Society of India 84, no. 5 (November 2014): 531–43. http://dx.doi.org/10.1007/s12594-014-0161-8.
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Khalid, Adnan, Sajjad Ahmad, Asghar Ali, Gohar Rehman, and Muhammad Yaseen. "Structural Analysis of Kirthar Fold Belt, Lower Indus Basin, Balochistan, Pakistan; Implications from Compression and Inversion Tectonics." Sains Malaysiana 52, no. 2 (February 28, 2023): 417–30. http://dx.doi.org/10.17576/jsm-2023-5202-08.
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The current research work mainly focuses on tectonic evolution of the Central Kirthar Fold Belt. It also deals with the structural impact of the Late Cretaceous/Paleocene, Indian-Eurasian collision on the Central Kirthar Fold Belt which is situated in the western shear zone of Indian Plate. The Kirthar Fold Belt is different from the rest of western shear zone because it is mainly deformed by compressional tectonics which has created wide anticlines, narrow synclines and overturned folds as shown by geological mapping. It has been observed that thin-skinned deformation has played a major role in structural disharmony which is mainly seen in the Early Eocene Ghazij and Oligocene Nari formations. Seismic data shows thick-skinned deformation because the faults seem to penetrate deeper stratigraphic levels. Involvement of the basal decollement and the penetration of the interpreted faults to the level of basement rocks is also evident from the exposure of Jurassic/Cretaceous rocks at surface on the western part of the mapped area. Cross sections data shows that Kirthar Thrust Fault has a structural throw around 3-4 km in the Kirthar Folded Zone featuring deformational front while the seismic data and well data shows that this intensity decreases in the Kirthar Foredeep Zone towards east where the structural throw is about 2-3 km. Restoration of cross sections show an overall 17.3% shortening which shows that the area is under influence of compressional stresses.
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Kashin, Valeriy P. "Between the Temple and the Mosque in Varanasi." Asia and Africa Today, no. 4 (2023): 54. http://dx.doi.org/10.31857/s032150750025337-2.
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The conflict in the Indian city of Varanasi caused by the request of the Hindus to be allowed to enter the territory of Gyanvapi mosque to perform their rituals is in the center of the author’s attention. The mosque was constructed in 1669 on the site of the demolished Hindu temple. In 2021 a stone cylinder, which is supposed to be the symbol of Shiva, was found in the water tank used by the Muslims to wash themselves before the Namaz. Nevertheless, the representatives of the mosque think the object is the basement of the fountain. The case of Gyanvapi mosque received a wide public response and caused a surge of legal proceedings in the courts of the country. Radically concerned Hindu nationalists threaten to demolish the Gyanvapi mosque, as it happened in 1992 with Babri Masjid in Ayodhya. The Prime Minister Narendra Modi has repeatedly received delegations of Muslim communal leaders. He promised support for the protection of mosques and madrasas’ property and government assistance in educational programs for the Muslim youth. Nonetheless, Modi cannot stop people from applying to courts.
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Barr, Sandra M., Sonya A. Dehler, and Louis Zsámboki. "Connecting Cape Breton Island and Newfoundland, Canada: Geophysical Modeling of pre-Carboniferous 'Basement' Rocks in the Cabot Strait Area." Geoscience Canada 41, no. 2 (May 7, 2014): 186. http://dx.doi.org/10.12789/geocanj.2014.41.041.
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Magnetic and gravity data from northeastern Cape Breton Island, southwestern Newfoundland, and the intervening Cabot Strait area were compiled and used to generate a series of maps displaying magnetic (filtered total field, first and second derivative) and gravity (Bouguer anomaly onshore, free-air anomaly offshore) information to enhance the anomaly pattern associated with regional geology. With further constraints from previously published seismic reflection interpretations and detailed maps of onshore geology, five two-dimensional subsurface models were generated. Potential field anomalies in the offshore can be correlated with onshore faults, rock units, and pre-Carboniferous terranes. In Newfoundland, the Cabot – Long Range Fault separates Grenvillian basement to the northwest from peri-Gondwanan Port aux Basques subzone basement in the southeast and can be traced to the Wilkie Brook Fault on Cape Breton Island. The Cape Ray Fault/Red Indian Line merges offshore with the Cabot – Long Range Fault so that Notre Dame subzone rocks do not extend across the Cabot Strait area. The Port aux Basques – Exploits subzone boundary crosses the strait but is likely buried by younger rocks onshore in Cape Breton Island. Magnetic halos in the Exploits subzone are probably caused by Silurian – Devonian plutons like those in the Burgeo Intrusive Suite. The Exploits – Bras d’Or terrane boundary is located within the Ingonish magnetic anomaly, which was resolved into four overlapping components representing basement sources intruded into metasedimentary rocks and dioritic and granodioritic plutons of the Bras d’Or terrane. The Bras d’Or terrane can be traced to the Cinq-Cerf block and Grey River areas in southern Newfoundland. The interpretations suggest that Bras d’Or terrane ‘basement’ may underlie all of Exploits subzone, and that the Aspy terrane of Cape Breton Island is part of that subzone. SOMMAIRELes données magnétométriques et gravimétriques du nord-est de l’île du Cap-Breton, dans le sud-ouest de Terre-Neuve, et de la région du détroit de Cabot contigu, ont été compilées et utilisées pour produire une série de cartes affichant les particularités magnétiques (champ total filtré, dérivé première et seconde) et gravimétriques (anomalie de Bouguer de la côte, anomalie à l’air libre extracôtière) pour ajouter à la compréhension des motifs d’anomalie de la géologie régionale. En tenant compte des limitations imposées par les interprétations de données de levés de sismique réflexion déjà publiées et de cartes détaillées de géologie continentale, cinq modèles 2D du sous-sol ont été produits. Des anomalies de champ potentiel en zone extracôtière peuvent être corrélées avec des failles, des unités lithologiques et des terranes pré-carbonifères sur la côte. Sur l’île de Terre-Neuve, la faille de Cabot-Long Range qui sépare le socle grenvillien au nord-ouest de la sous-zone de socle péri-gondwanienne, de Port-aux- Basques au sud-est, peut être reliée à la faille de Wilkie Brook sur l’île du Cap-Breton. La faille du Cap Ray et la linéation de Red Indian se fondent au large avec la faille de Cabot – Long Range, ce qui signifie que les roches de la sous-zone de Notre-Dame ne traversent pas la région du détroit de Cabot. La limite de la sous-zone de Port aux Basques-Exploits traverse le détroit, mais elle est vraisemblablement enfouie sous des roches plus jeunes sur l’île du Cap-Breton. Les halos magnétiques dans la sous-zone Exploits sont probablement causés par des plutons siluro-dévoniens comme c’est le cas de ceux de la séquence intrusive de Burgeo. La limite du terrane Exploits-Bras d’Or est située dans l’anomalie magnétique Ingonish, laquelle s’est révélée être constituée de quatre composantes superposées représentant des sources de socle engoncées dans des roches métasédimentaires, et dans des plutons dioritiques et granodioritiques du terrane de Bras d’Or. On peut suivre le terrane de Bras d’Or jusque dans les régions du bloc de Cinq-Cerf et de Grey River dans le sud de Terre-Neuve. Les interprétations permettent de penser que le « socle » du terrane de Bras d’Or pourrait constituer l’assise rocheuse de la sous-zone Exploits, et que le terrane Aspy de l’île du Cap-Breton ferait partie de cette sous-zone.
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Karamatic Crew, Vanja, Nicholas Burton, Alexander Kagan, Carole A. Green, Cyril Levene, Frances Flinter, R. Leo Brady, Geoff Daniels, and David J. Anstee. "CD151, the first member of the tetraspanin (TM4) superfamily detected on erythrocytes, is essential for the correct assembly of human basement membranes in kidney and skin." Blood 104, no. 8 (October 15, 2004): 2217–23. http://dx.doi.org/10.1182/blood-2004-04-1512.
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Abstract Tetraspanins are thought to facilitate the formation of multiprotein complexes at cell surfaces, but evidence illuminating the biologic importance of this role is sparse. Tetraspanin CD151 forms very stable laminin-binding complexes with integrins α3β1 and α6β1 in kidney and α3β1 and α6β4 in skin. It is encoded by a gene at the same position on chromosome 11p15.5 as the MER2 blood group gene. We show that CD151 expresses the MER2 blood group antigen and is located on erythrocytes. We examined CD151 in 3 MER2-negative patients (2 are sibs) of Indian Jewish origin with end-stage kidney disease. In addition to hereditary nephritis the sibs have sensorineural deafness, pretibial epidermolysis bullosa, and β-thalassemia minor. The 3 patients are homozygous for a single nucleotide insertion (G383) in exon 5 of CD151, causing a frameshift and premature stop signal at codon 140. The resultant truncated protein would lack its integrin-binding domain. We conclude that CD151 is essential for the proper assembly of the glomerular and tubular basement membrane in kidney, has functional significance in the skin, is probably a component of the inner ear, and could play a role in erythropoiesis.
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Papavassiliou, C. T. "GEOCHEMICAL- MINERALOGICAL AND METALLOGENETICAL ASPECTS CONCERNING THE ORIGIN OF SEDIMENTS FROM LEG. 22 D.S.D.P DRILLED SITES 212 AND 213 IN EASTERN INDIAN OCEAN." Bulletin of the Geological Society of Greece 40, no. 2 (January 1, 2007): 918. http://dx.doi.org/10.12681/bgsg.16747.
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Basic mineralogical and geochemical data, are presented for sediment core samples from Deep Sea Drilling Project(D.S.D.P) boreholes .Sites 212 and 213 respectively, from the eastern Indian Ocean. In both Sites the Fe-Mn oxides are abundant controlling a numerous suite of trace elements. In Site 212 the Fe-Mn oxides are more abundant in the upper part of the borehole having mainly a diagenetic or hydrogenous origin, whilst in Site 213 these oxides are more abundant in the lower part having mainly a hydrothermal origin. In both Sites clay minerals are consisting mostly of the expandable mixed layered smectite/illite. The geochemical data shows that in both Sites the majority of the sediments have the characteristics of typical deep sea clay being both of detrital and authigenic origin. In Site 212 these clays with considerable amount of palygorskite and the zeolite clinoptilolite, both of authigenic origin, opaline silica, biogenous CaCOj ,the Fe-Mn oxides and some other detrital minerals together control the bulk chemical composition of the sediments. In Site 213 the clays with large amounts of Fe-Mn oxides and considerable amounts of the zeolite Phillipsite and Palygorskite in small amounts and some other detrital minerals, control the chemical composition of the sediments. The increase in the Ti/Al and Mg/Al ratios with depth in both Sites implies a volcanoclastic input in the bottom sediments probably from the underlying basaltic basement
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Valdiya, K. S. "Emergence and evolution of Himalaya: reconstructing history in the light of recent studies." Progress in Physical Geography: Earth and Environment 26, no. 3 (September 2002): 360–99. http://dx.doi.org/10.1191/0309133302pp342ra.
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India collided with mainland Asia at 65 Ma. The pressure rose to 9-11 kbar in the collision zone. As the Indian lithosphere bent down and its upper crust buckled up as an upwarp in the period 35-45 Ma, the southern margin of Asia became the water-divide of the Himalayan rivers. A variety of Eurasian fauna migrated to the Indian landmass. The southern margin of the Himalayan province synchronously sagged to give rise to the foreland basin that was linked with the Indian sea. In this Paleocene foreland basin 48-49 Ma ago, the whales from one of the species of the immigrant terrestrial mammals evolved. The sea retreated from the Himalayan province by the early Miocene, even as the crust broke up along faults 20-22 million years ago. The basement rocks, which had attained high-grade metamorphism at 600-800°C and 6-10 kbar, were thrust up to give rise to what later became the Himādri or Great Himalaya. Differential melting of the high-grade metamorphic rocks of the Himadri extensively produced 21 ± 1 Maold granites. Rivers carried detritus generated by the denudation of the fast emerging Himalaya and deposited it in the foreland basin which turned fluvial around 23 Ma. Another fluvial foreland basin, the Siwalik, was formed at ~18 Ma in front of the rapidly rising orogen and was filled by river-borne sediments at the rate of 20-30 cm year-1 in the early stage and at 50-55 cm year-1 later when the Himadri was uplifted and briskly exhumed in the Late Miocene (9-7.5 Ma). The Himadri then became high enough to cause disruption of wind circulation, culminating in the onset of monsoon. The climate change that followed caused migration of a variety of quadrupeds from Africa and Eurasia, bringing about considerable faunal turnovers in the Siwalik life. Spasmodic uplift of the outer ranges of the Lesser Himalaya and tectonic convulsion in the Siwalik domain at 1.6 Ma resulted in widespread landslides with debris flows and emplacement of the Upper Siwalik Boulder Conglomerate. Strong tectonic movements at 0.8 Ma caused the partitioning of the foreland basin into the rising Siwalik Hills and the subsiding IndoGangetic Plains, and also the initiation of glaciation in the uplifted domain of the Great Himalaya. After the end of the Pleistocene ice age around 0.2 Ma, there was oscillation of dry-cold and wet-warm climates. This climatic vicissitude is recorded in the sediments of the lakes that had formed because of reactivation of faults crossing rivers and streams. Activeness of faults, continuing uplift and current seismicity imply ongoing strain-buildup in the Himalayan domain.
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Kimeli, Amon, Oliver Ocholla, Judith Okello, Nico Koedam, Hildegard Westphal, and James Kairo. "Geochemical and petrographic characteristics of sediments along the transboundary (Kenya–Tanzania) Umba River as indicators of provenance and weathering." Open Geosciences 13, no. 1 (January 1, 2021): 1064–83. http://dx.doi.org/10.1515/geo-2020-0275.
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Abstract The Umba River basin is one of the smaller-scale hydrological basins in the East African region. It traverses two countries, with its catchment in the Usambara mountains in Tanzania, while it drains its waters to the Indian Ocean in Vanga, Kenya. The chemical and mineralogical compositions of the riverbank and bottom sediments of the Umba River were analyzed and evaluated to describe their source characteristics and provenance. The dominant minerals include quartz, K-feldspars, plagioclase, hornblende, pyroxenes, muscovite, biotite, and likely presence of clays such as kaolinite. The chemical index of alteration of the sediments indicate a moderate to high degree of alteration. They reflect a dominant mafic to intermediate igneous provenance consistent with the geology of the Umba River catchment that is characterized by the outcrops of the granitic Precambrian basement and the quartz-dominated Paleozoic Karoo Supergroup, overlain by Mesozoic and Cenozoic sediments dominated by both mafic and felsic minerals. The similarity of the chemical and mineralogical compositions of the Umba River sediments from source to mouth further indicates a uniform source in the upper course of the river and only subordinate contributions from the lower course where it passes the Karoo and the younger sediments.
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Coombs, April M., Alex Zagorevski, Vicki McNicoll, and John M. Hanchar. "Preservation of terranes during the assembly of the Annieopsquotch Accretionary Tract: Inferences from the provenance of a Middle Ordovician ophiolite to arc transition, central Newfoundland Appalachians1Geological Survey of Canada Contribution 20100463.2This article is one of a series of papers published in this CJES Special Issue: In honour of Ward Neale on the theme of Appalachian and Grenvillian geology." Canadian Journal of Earth Sciences 49, no. 1 (January 2012): 128–46. http://dx.doi.org/10.1139/e11-042.
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The Newfoundland Appalachians are a classic area for studying the record of arc development and terrane accretion processes with excellent exposure to different crustal levels that are minimally deformed and metamorphosed. This area also provides a link between the once continuous Appalachian and Caledonian orogens. The Annieopsquotch Accretionary Tract lies along the Red Indian Line, within the peri-Laurentian realm of the central Newfoundland Appalachians. The Darriwilian (468–461 Ma) tectonostratigraphic units of the Annieopsquotch Accretionary Tract are commonly characterized by polymictic volcanogenic conglomerate horizons. A conglomerate horizon at the interface between a suprasubduction zone ophiolite and its calc-alkaline volcanic arc cover sequence is herein investigated for zircon and geochemical provenance. Geochronology revealed a maximum age of deposition of 467 ± 4 Ma with zircon inheritance ranging from ca. 500 to 2800 Ma, consistent with a peri-Laurentian continental basement source. Four types of volcanogenic conglomerate clasts are noted on the basis of lithogeochemistry: arc andesite; calc-alkaline basalt; tholeiitic basalt; and non-arc rhyodacite. Tholeiitic basalt clasts are likely locally derived, perhaps from the underlying Skidder Formation. Other volcanic clasts do not have any known geochemical equivalents in the Annieopsquotch Accretionary Tract and hence appear to be exotic. The dominant zircon population suggests that the exotic clasts were derived from a ca. 467 Ma peri-Laurentian andesitic volcanic arc that once formed part of the Annieopsquotch Accretionary Tract.
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Duvall, Michael J., John W. F. Waldron, Laurent Godin, and Yani Najman. "Active strike-slip faults and an outer frontal thrust in the Himalayan foreland basin." Proceedings of the National Academy of Sciences 117, no. 30 (July 13, 2020): 17615–21. http://dx.doi.org/10.1073/pnas.2001979117.
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The Himalayan foreland basin formed by flexure of the Indian Plate below the advancing orogen. Motion on major thrusts within the orogen has resulted in damaging historical seismicity, whereas south of the Main Frontal Thrust (MFT), the foreland basin is typically portrayed as undeformed. Using two-dimensional seismic reflection data from eastern Nepal, we present evidence of recent deformation propagating >37 km south of the MFT. A system of tear faults at a high angle to the orogen is spatially localized above the Munger-Saharsa basement ridge. A blind thrust fault is interpreted in the subsurface, above the sub-Cenozoic unconformity, bounded by two tear faults. Deformation zones beneath the Bhadrapur topographic high record an incipient tectonic wedge or triangle zone. The faults record the subsurface propagation of the Main Himalayan Thrust (MHT) into the foreland basin as an outer frontal thrust, and provide a modern snapshot of the development of tectonic wedges and lateral discontinuities preserved in higher thrust sheets of the Himalaya, and in ancient orogens elsewhere. We estimate a cumulative slip of ∼100 m, accumulated in <0.5 Ma, over a minimum slipped area of ∼780 km2. These observations demonstrate that Himalayan ruptures may pass under the present-day trace of the MFT as blind faults inaccessible to trenching, and that paleoseismic studies may underestimate Holocene convergence.
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Talukdar, Susmita. "Story-telling Silk Route Collapsing the Walls of Differences: An Analysis on Chitra Banerjee Divakaruni’s One Amazing Thing." Literary Studies 29, no. 01 (December 1, 2016): 68–72. http://dx.doi.org/10.3126/litstud.v29i01.39614.
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The article examines power of narrative/storytelling in developing collective force that would serve as survival strategy for facing catastrophe. In Divakaruni’s One Amazing Thing the nine characters, who are trapped by a major earthquake in the basement of a high-rise building of Indian visa office in US, go on telling his/her stories of their past, ‘one amazing thing’ of their lives that they have never been able to share with anyone. Like a very ancient story telling form e.g. the Panchatantra, stories lead to more stories. One story makes the listeners to muse about how it applies to their lives, and that ultimately leads them coming up with their own stories, the choice of which is influenced by the previous story. In their manner of telling stories, the characters feel strangely bound to each other, though they are so different from each other. It is the incredible power of storytelling that collapses the wall of several tags of identity, and brings together the strangers, who are stuck in one room due to natural disaster. Ironically the story takes place in a visa office that confirms one’s identity in terms of his/her nationality, race, ethnicity and similar others. It is a natural disaster that brings people from different origin closer to each other and it is the healing power of narrative/storytelling that dissolves all differences revealing what it means to be human.
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Buslov, M. M. "Stress-strain state of the earth’s crust of the Central Asian mountain belt: distant effect of the tectonic impact of the Indo-Eurasian collision." IOP Conference Series: Earth and Environmental Science 929, no. 1 (November 1, 2021): 012003. http://dx.doi.org/10.1088/1755-1315/929/1/012003.
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Abstract In recent decades, extensive geological, geophysical and geochronological data have been obtained that characterize in detail the results of the distant tectonic impact of the Indo-Eurasian collision on the lithosphere of Central Asia, which led to the formation of the mountain systems of the Pamirs, Tien Shan, Altai-Sayan region and Transbaikalia from the Late Paleogene (about 25 million years ago). It has been established that the formation of the structure of Central Asia occurred as a result of the transmission of deformations from the Indo-Eurasian collision over long distances according to the “domino principle” through the rigid structures of Precambrian microcontinents located among the Paleozoic-Mesozoic folded belts. The study of peneplain surfaces deformed into simple folds on high-mountain plateaus surrounded by rugged mountain ranges made it possible to reveal the parameters of the deformations of the earth’s crust, the interrelationship of the formation of relief and sedimentary basins. Apatite track dating data, structural and stratigraphic analyses of Late Cenozoic sediments in the basins prove a period of intense tectonic activation the entire lithosphere of Central Asia from the Indian continent to the Siberian platform starting from the Pliocene (about 3.5 million years). As a result of reactivation of the heterogeneous basement of Central Asia, high seismicity was manifested, which is concentrated mainly along the border of the microcontinents (Central Tianshan, Junggar and Tuva-Mongolian) and the Siberian craton, as well as in the zones of articulation of regional faults.
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Loosveld, Ramon J. H., Andy Bell, and Jos J. M. Terken. "The Tectonic Evolution of Interior Oman." GeoArabia 1, no. 1 (January 1, 1996): 28–51. http://dx.doi.org/10.2113/geoarabia010128.
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ABSTRACT The evolution of Oman’s onshore sedimentary basins from the Late Precambrian to the Present is reflected by six tectono-stratigraphic units. Unit I, the Precambrian basement, represents continental accretion. Units II and III, Infracambrian to Ordovician, may reflect two periods of rifting, possibly related to Najd movements in western Saudi Arabia. The northeast-southwest trending salt basins formed during this time interval. A classical “steer’s head” basin geometry is developed in North Oman, whereas a less complete rift-sag sequence is preserved in South Oman. Of the entire time-span from Late Silurian to Mid-Carboniferous, only little Devonian (Emsian) sediment is preserved. Unit IV, Late Carboniferous to Mid-Cretaceous, reflects the break-up of Gondwana and the creation of the northeastern and southeastern passive margins of the Arabian Plate. Unit V documents intra-plate deformation related to Late Cretaceous continent-ocean obduction in the north and transpressional movements of the Indian Plate in the east. Unit VI, spanning the Tertiary, represents a return to quiet conditions followed by continent-continent collision in the north. Following Late Eocene uplift, the Gulf of Aden rift developed in the south in the early Oligocene, with sea-floor spreading from the Late Miocene onwards. Salt flow and dissolution, both playing a major role in the configuration of most intra- and post-salt hydrocarbon traps in Oman, are episodic and can be related to tectonic events.
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Dorais, Michael J., Miles Atkinson, Jon Kim, David P. West, and Gregory A. Kirby. "Where is the Iapetus suture in northern New England? A study of the Ammonoosuc Volcanics, Bronson Hill terrane, New Hampshire1This article is one of a series of papers published in this CJES Special Issue: In honour of Ward Neale on the theme of Appalachian and Grenvillian geology." Canadian Journal of Earth Sciences 49, no. 1 (January 2012): 189–205. http://dx.doi.org/10.1139/e10-108.
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The ∼470 Ma Ammonoosuc Volcanics of the Bronson Hill terrane of New Hampshire have back-arc basin basalt compositions. Major and trace element compositions compare favorably to coeval volcanic rocks in the Miramichi Highlands of New Brunswick and the Munsangan and Casco Bay volcanics of Maine, back-arc basin basalts of known peri-Gondwanan origins. Additionally, the Ammonoosuc Volcanics have Nd and Pb isotopic compositions indicative of peri-Gondwanan provenance. Thus, the Ammonoosuc Volcanics correlate with Middle Ordovician, peri-Gondwanan, Tetagouche–Exploits back-arc rocks of eastern New England and Maritime Canada. This correlation indicates that the Red Indian Line, the principle Iapetus suture, lies along the western margin of the Bronson Hill terrane. However, the younger (∼450 Ma) Oliverian Plutonic Suite rocks that intruded the Ammonoosuc Volcanics, forming domes along the core of the Bronson Hill anticlinorium, have Laurentian isotopic signatures. This suggests that the Ammonoosuc Volcanics were thrust westwardly over the Laurentian margin, and that Laurentian basement rocks are present under the Bronson Hill terrane. A plausible explanation for these relationships is that an easterly dipping subduction zone formed the Ammonoosuc Volcanics in the Tetagoughe–Exploits oceanic tract, just east of the coeval Popelogan arc. With the closure of the Iapetus Ocean, this terrane was thrust over the Laurentian margin. Subsequent to obduction of the Ammonoosuc Volcanics, subduction polarity flipped to the west, with the Oliverian arc resulting from a westerly dipping subduction zone that formed under the Taconic Orogeny-modified Laurentian margin.
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Dunn, T. S., W. A. Nizami, and R. E. B. Hanna. "Studies on the ultrastructure and histochemistry of the lymph system in three species of amphistome (Trematoda: Digenea) Gigantocotyle explanatum, Gastrothylax crumenifer and Srivastavaia indica from the Indian Water Buffalo Bubalus bubalis." Journal of Helminthology 59, no. 1 (March 1985): 1–18. http://dx.doi.org/10.1017/s0022149x00034416.
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AbstractThe lymph system of three amphistome parasites from buffaloes, Gigantocotyle explanatum, Gastrothylax crumenifer and Srivastavaia indica was studied using light microscope histochemistry and electron microscopy. In each case the system comprised a single pair of main longitudinal vessels which gave rise to numerous sub-dividing lateral branches. Although the finer lymph channels associated with most internal systems, they did not penetrate the basement membrane of any organ. The lymph vessels were delimited by a unit membrane and separated from adjacent cells by interstitial material. The lymph fluid consisted of an amorphous proteinaceous, lipid-rich matrix, containing naked nuclei and granules of various sizes. Complexes of endoplasmic reticulum were frequently associated with the nuclei. No distinct Golgi bodies or mitochondria were evident. The granules noted throughout the lymph morphologically resembled autophagosomes and lysosomes. Autophagy within the lymph system presumably mobilizes amino acids for subsequent transport to tissues undergoing active protein synthesis. The lymph channels displayed an intimate relationship with the general parenchyma. In particular, numerous protrusions of lymph occurred into the cytoplasm of certain specialized parenchymal cells surrounding the pharynx. Within these ‘juxtapharyńigeal’ cells autophagic degradation of sequestered lymph cytoplasm apparently occurred. In the three species of amphistome studied, the lymph system appears to function in storage and mobilization of amino acids and possibly lipids. It may also serve to distribute other small molecules throughout the body. The detection of haemoglobin in the lymph system of G. crumenifer and S. indica, but not in Gigantocotyle explanatum, suggests a further role in oxygen storage and transport.
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Droxler, André W., and Stéphan J. Jorry. "The Origin of Modern Atolls: Challenging Darwin's Deeply Ingrained Theory." Annual Review of Marine Science 13, no. 1 (January 3, 2021): 537–73. http://dx.doi.org/10.1146/annurev-marine-122414-034137.
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In 1842, Darwin identified three types of reefs: fringing reefs, which are directly attached to volcanic islands; barrier reefs, which are separated from volcanic islands by lagoons; and ring reefs, which enclose only a lagoon and are defined as atolls. Moreover, he linked these reef types through an evolutionary model in which an atoll is the logical end point of a subsiding volcanic edifice, as he was unaware of Quaternary glaciations. As an alternative, starting in the 1930s, several authors proposed the antecedent karst model; in this model, atolls formed as a direct interaction between subsidence and karst dissolution that occurred preferentially in the bank interiors rather than on their margins through exposure during glacial lowstands of sea level. Atolls then developed during deglacial reflooding of the glacial karstic morphologies by preferential stacked coral-reef growth along their margins. Here, a comprehensive new model is proposed, based on the antecedent karst model and well-established sea-level fluctuations during the last 5 million years, by demonstrating that most modern atolls from the Maldives Archipelago and from the tropical Pacific and southwest Indian Oceans are rooted on top of late Pliocene flat-topped banks. The volcanic basement, therefore, has had no influence on the late Quaternary development of these flat-topped banks into modern atolls. During the multiple glacial sea-level lowstands that intensified throughout the Quaternary, the tops of these banks were karstified; then, during each of the five mid-to-late Brunhes deglaciations, coral reoccupied their raised margins and grew vertically, keeping up with sea-level rise and creating the modern atolls.
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Yan, Dong, You Tian, Zhiqiang Li, and Hongli Li. "Upper Mantle Velocity Structure Beneath the Yarlung–Tsangpo Suture Revealed by Teleseismic P-Wave Tomography." Remote Sensing 15, no. 11 (May 24, 2023): 2724. http://dx.doi.org/10.3390/rs15112724.
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We applied teleseismic tomography to investigate the 3D P-wave velocity (Vp) structure of the crust and upper mantle at depths of 50–400 km beneath the Yarlung–Tsangpo suture (YTS), by using 6164 P-wave relative travel-time residuals collected from 495 teleseismic events recorded at 20 three-component broadband seismograms. A modified multi-channel cross-correlation method was adopted to automatically calculate the relative arrival-time residuals of all teleseismic events, which significantly improved the efficiency and precision of the arrival-time data collection. Our results show that alternating low- and high-Vp anomalies are visible beneath the Himalayan and Lhasa blocks across the YTS, indicating that strong lateral heterogeneities exist beneath the study region. A significant high-Vp zone is visible beneath the southern edge of the Lhasa block at 50–100 km depths close to the YTS, which might indicate the rigid Tibetan lithosphere basement. There exists a prominent low-Vp zone beneath the Himalayan block to the south of the YTS extending to ~150 km depth, which might be associated with the fragmentation of the underthrusting Indian continental lithosphere (ICL) and induce localized upwelling of asthenospheric materials from the upper mantle. In addition, significant low-Vp anomalies were observed beneath the Yadong–Gulu rift and the Cona–Sangri rift extending to ~300 km depth, indicating that the tearing of the subducted ICL might provide pathways for the localized asthenospheric materials upwelling, which contributes to the widespread distribution of north–south trending rifts and geothermal activities in southern Tibet.
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Yan, Yu-Hao, Bing-Jia Li, Wei-Ren Pan, Liang Song, Lin-Lin Fu, Chuan-Xiang Ma, Fan-Qiang Zeng, and M. Dip. "Morphology and Ultrastructure of the Collecting Lymph Vessel, Lumbar Trunk and Thoracic Duct in the Rat." Scholars Journal of Applied Medical Sciences 10, no. 3 (March 11, 2022): 286–90. http://dx.doi.org/10.36347/sjams.2022.v10i03.004.
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Objective: To determine morphological and ultrastructural details of the collecting lymph vessel, lumbar trunk and thoracic duct of the rat. Methods: Sixteen adult SD rats were utilized for the study. A small amount of 6% hydrogen peroxide was applied to find the lymph vessel in the dorsodistal hind-limb and sides of the abdominal aorta in the rat. Under a surgical microscope, the vessel was injected by Indian ink or a radiopaque mixture via a fine needle to locate sites of the collecting lymphatic vessel, lumbar trunk and thoracic duct. Vessels were then harvested for the histological and transmission electron microscopic examinations. Results: Diameters of the collecting lymph vessel, lumbar trunk and thoracic duct in the rat were diverse, small in the former and large in the latter. Containing multiple valves in the lumen, their walls were very thin and composed of three layers of tissue. Ultrastructures of the tunica intima and externa of these vessels were similar. A single layer of endothelium cells with a discontinuous basement membrane formed the tunica intima of the vessel. One or two discontinuous layers of smooth muscle cells was found in the tunica media of the collecting lymph vessel, one to three layers of smooth muscle cells in the lumbar trunk and three to five layers of smooth muscle cells in the thoracic duct. The tunica externa of the vessel was comprised by connective tissue (collagen fibrils) and fibroblasts. Conclusion: Morphological and ultrastructural details of the collecting lymph vessel, lymphatic trunk and duct in the rat have been demonstrated that may help for the purpose of further lymphatic vessels studies.
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Affinati, Suzanne Craddock, Thomas D. Hoisch, Michael L. Wells, and Jeffrey D. Vervoort. "Pressure-temperature-time paths from the Funeral Mountains, California, reveal Jurassic retroarc underthrusting during early Sevier orogenesis." GSA Bulletin 132, no. 5-6 (September 17, 2019): 1047–65. http://dx.doi.org/10.1130/b35095.1.
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Abstract New metamorphic pressure-temperature (P-T) paths and Lu-Hf garnet ages reveal a temporal correlation between Middle to Late Jurassic retroarc underthrusting and arc magmatism in southwestern North America. P-T paths were determined for 12 garnet porphyroblasts from six samples from the Chloride Cliff area of the Funeral Mountains in southeastern California. The composite path shows a pressure increase from 4.2 to 6.5 kbar as temperature increased from 550 to 575 °C, followed by a pressure decrease to 5.1 kbar during a further increase in temperature to 590 °C. Lu-Hf garnet ages from a pelitic schist (167.3 ± 0.7 Ma) and a garnet amphibolite (165.1 ± 9.2 Ma) place these P-T paths in the Middle Jurassic. We interpret the near-isothermal pressure increase portion of the P-T path to have developed during thrust-related burial, similar to lower grade rocks at Indian Pass, 8 km to the southeast, where garnet P-T paths show a pressure increase dated by the Lu-Hf method at 158.2 ± 2.6 Ma. We interpret the pressure decrease portion of the composite P-T path from the Chloride Cliff area to reflect exhumation contemporaneous with cooling in the Indian Pass area documented from muscovite 40Ar/39Ar step-heating ages of 152.6 ± 1.4 and 146 ± 1.1 Ma. The conditions and timing of metamorphism determined for the Indian Pass and Chloride Cliff areas, and isogradic surfaces that cut across stratigraphy, support the interpretation that the strata were dipping moderately NW during metamorphism, parallel to the thrust ramp that buried the rocks. Burial likely resulted from top-SE motion along the Funeral thrust, which was later reactivated as a low-angle normal fault with opposite motion to become the currently exposed Boundary Canyon detachment that was responsible for Miocene and possibly older exhumation. The part of the burial history captured by garnet growth occurred ∼6 m.y. before the 161 Ma peak of high-flux magmatism in the arc. Burial was contemporaneous with metamorphic ages from the western Sierra Nevada metamorphic belt, with the possible timing of accretion of arc terranes in northern California, and with the initiation of Franciscan subduction. Burial ages are also similar in timing with generally E-W crustal shortening in the retroarc that produced the East Sierra thrust system, the Luning-Fencemaker fold and thrust belt, the possible early history of the Central Nevada thrust belt, and the western thrusts of the southern Sevier belt. The timing of tectonic burial documented in this study and of high-flux magmatism in the arc supports the interpretation that the development of a coherent arc-trench system in the Early Jurassic resulted in the underthrusting of melt-fertile material beneath the arc along west- to northwest-dipping faults such as the Funeral thrust in the Jurassic, which penetrated the basement to the west as well as the roots of the magmatic arc, leading to increased magmatism.