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Singh, Sandeep
- Ductile Shearing of the Proterozoic Chor Granitoid in the Lesser Himalaya and its Tectonic Significance
Abstract Views :186 |
PDF Views:167
Authors
Sandeep Singh
1,
A. K. Jain
1
Affiliations
1 Department of Earth Sciences, University of Roorkee, Roorkee - 247 667, IN
1 Department of Earth Sciences, University of Roorkee, Roorkee - 247 667, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 47, No 1 (1996), Pagination: 133-138Abstract
A newly identified Chor Thrust demarcates the southern margin of the Proterozoic Chor granitoid massif within the Jutogh Group metamorphics of the Lesser Himalaya in Himachal Pradesh. Numerous shear criteria reveal a topto- SW overthrust-type Intense ductile strain along this margin and are consistent with the southward propagating nappes.- Biotite Rb-Sr Ages: Constraints on Exhumation of the Karakoram Metamorphic Complex, Eastern Ladakh
Abstract Views :182 |
PDF Views:112
Authors
Affiliations
1 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Geochronology Division, KDMIPE, ONGC, Kaulagarh Road, Dehradun - 248 001, IN
3 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667
1 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Geochronology Division, KDMIPE, ONGC, Kaulagarh Road, Dehradun - 248 001, IN
3 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 67, No 1 (2006), Pagination: 27-31Abstract
Biotite and K-feldspar Rb-Sr ages from three granitoid intrusives within the Karakoram Metamorphic Belt (KMB), eastern Ladakh yield indistinguishable ages between 12-10 Ma. Since the closure temperature of biotite for Sr diffusion is 300±50°C, we interpret these ages due to exhumation at 10 to 7 km depth within the crust. This implies that the Pangong Metamorphic Belt of the KMB, located at the southern termination of the Eurasian Plate, was undergoing a fast exhumation in a transpressional regime during Middle Miocene. These data also indicates that the southern edge of the Eurasian Plate has exhumed rapidly in comparison to the Higher Himalayan Crystallines within the Indian Plate segment.Keywords
Rb-Sr Ages, Granitoids, Karakoram Complex, Eastern Ladakh.- 2.0 Ga Granite of the Lower Package of the Higher Himalayan Crystallines, Maglad Khad, Sutlej Valley, Himachal Pradesh
Abstract Views :238 |
PDF Views:154
Authors
Sandeep Singh
1,
Stefan Claesson
2,
A. K. Jain
1,
David G. Gee
3,
P. G. Andreasson
4,
R. M. Manickavasagam
5
Affiliations
1 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Laboratory for Isotope Geology, Swedish Museum of Natural History, Box 50007, SE- 104 05 Stockholm, SE
3 Department of Earth Sciences, Uppsala University, Villavagen 16, SE-752 36, Uppsala, SE
4 Department of Lithosphere and Biosphere Science, Solvegatan 12, SE-223 62, Lund, SE
5 Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee 247 667, IN
1 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Laboratory for Isotope Geology, Swedish Museum of Natural History, Box 50007, SE- 104 05 Stockholm, SE
3 Department of Earth Sciences, Uppsala University, Villavagen 16, SE-752 36, Uppsala, SE
4 Department of Lithosphere and Biosphere Science, Solvegatan 12, SE-223 62, Lund, SE
5 Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee 247 667, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 67, No 3 (2006), Pagination: 295-300Abstract
Along the Sutlej valley, the lower package of the Higher Himalayan Crystallines (HHC) exposes a small concordant to discordant intrusive grey granite -The Maglad Khad Granite, within garnet mica schist/Banded gneiss of the Jeori Formation. This body is fine grained and foliated along the margins, whereas the central part is relatively undeformed. This body along with aplites and pegmatites intrudes the country rock during early to syn-D1 deformation. This is later affected by the most pervasive D2-deformation producing gneissosity within the granite. U-Pb dating of zircons by conventional isotopic dilution technique yield an upper intercept age of 2068±5 Ma (2σ) from 6 zircon-Fractions with MSWD=0.93, constraining the age of crystallization in the basal parts of the HHC during Early Proterozoic as well as the constraining pre-Himalayan fabric development.Keywords
Higher Himalayan Crystallines, Maglad Khad Granite, Geochronology, U-Pb Zircon Dating, Sutlej Valley, Himachal Pradesh.- Conventional and SHRIMP U-Pb Zircon Dating of the Chor Granitoia, Himachal Himalaya
Abstract Views :184 |
PDF Views:2
Authors
Affiliations
1 Department of Earth Sciences, Indian Institute of Technology, Roorkee - 247 667, IN
1 Department of Earth Sciences, Indian Institute of Technology, Roorkee - 247 667, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 62, No 5 (2003), Pagination: 614-626Abstract
Conventional zircon U-Pb analyses of optically clear multi-grain fractions from the Chor Granitoid sample - CH 1/1:provide a comp1ex pattern with eight points yielding a reference line with an upper intercept age of c. 910 Ma and large scatter. Three zircon fractions from the more deformed sample CH 4/11 of this body define a-discordia line with an imprecise upper and lower intercept ages of 859±11927 Ma and 460±264 Ma respectively. On the other hand, SHRIMP analyses of carefully selected core and rim of CH 1/1 zircon give magmatic rim/grain age of 823± 5 Ma with zircon cores having more than 5% discordant 207Pb/206Pb ages ranging from ∼900 Ma to ∼1560 Ma. The presence of older cores indicate that 0.9 Ga age obtained from conventional TlMS U-Pb technique is probably a mixed age of magmatic and inherited zircons.Keywords
U-Pb dating, Zircons, TIMS, SHRIMP, Chor granitoid, Himachal Himalaya.- Microstructures of Mylonites Along the Karakoram Shear Zone, Tangste Valley, Pangong Mountains, Karakoram
Abstract Views :220 |
PDF Views:0
Authors
Affiliations
1 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee – 247 667, IN
1 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee – 247 667, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 75, No 5 (2010), Pagination: 679-694Abstract
The Karakoram Shear Zone is a northwest-southeast trending dextral ductile shear zone, which has affected the granitic and granodioritic bodies of the southern Asian Plate margin in three distinct episodes. The ductile shearing of the granitic bodies at Tangste and Darbuk has resulted in the development of mylonites with mylonitic foliation and stretching lineation. More intense deformation is noted in the Tangste granite grading up to orthomylonite, as compared to the Darbuk granite. Kinematic indicators include S-C foliation, synthetic C' and C" antithetic shear bands, Type A s-mantled porphyroclasts, oblique quartz foliation, micro-shears with bookshelf gliding, mineral fishes including Group 2 mica fishes, and Type 1 and 2a pull-apart microstructures, and exhibit strong dextral sense of ductile shearing towards southeast. The textural features of the minerals, especially that of quartz and feldspar, indicate temperature of mylonitisation ranging between 300 and 500°C in the upper greenschist facies, and appear to have been evolved during exhumation as a consequence of oblique strike-slip movements along the Karakoram shear zone.Keywords
Karakoram Shear Zone, Mylonites, Texture, Kinematic Indicators, Karakoram, Uttarakhand.- Crustal Accretion and Metamorphism of Mesoarchean Granulites in Palghat-Cauvery Shear Zone, Southern India
Abstract Views :228 |
PDF Views:0
Authors
Affiliations
1 Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
1 Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN
2 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, IN