Journal of Himalayan Earth Sciences最新文献

{"title":"Tectonic Activity In The Ganga Plain Foreland Basin During Quaternary","authors":"I. Singh","doi":"10.3126/HJS.V5I7.1326","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1326","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1326 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.145","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"1 1","pages":"145-145"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79782459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palaeozoic granites and their younger components - A study of Mandi and Rakcham granites from the Himachal Himalaya","authors":"A. Kundu, N. Pant, S. Joshi","doi":"10.3126/HJS.V5I7.1278","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1278","url":null,"abstract":"HIMALAYAN JOURNAL OF SCIENCES | VOL. 5 | ISSUE 7 (SPECIAL ISSUE) | 2008 82 Several occurrences of Palaeozoic granites are recorded from the Lesser Himalayas as well as from the Higher Himalayas (Miller et al. 2001). From Himachal many such bodies have been dated (Bhanot et al. 1979, Frank et al. 1977, Jager et al. 1971, Kwatra et al. 1986, Pognante et al. 1990, Kwatra et al. 1999, Kundu et al. 2006). All of these bodies are deformed and several occur in the vicinity of Main Central Thrust (MCT). Studies have indicated presence of more than one granite type in most of these occurrences (e.g. Gupta 1974, Chatterjee 1976) but definitive reference to the Himalayan orogeny has generally been lacking. The present work supplements the earlier field and petrographic classification with rigorous mineralogical including rare earth element (REE) bearing mineral data for the two Paleozoic granites of Mandi and Rakcham and show association of younger granites with these occurrences. Four petrographic variants of Mandi granites can be identified (Chatterjee 1976). These are as follows. 1. Porphyritic granite: With two mica and two feldspar. The ratio of the micas number to feldspar phenocryst vary. The other mineral phases are quartz, ilmenite, sphene, epidote, zircon, secondary muscovite, chlorite, monazite, allanite, zircon, apatite and fluorite. 2. Fine grained porphyritic granite: Two mica two feldspar granite and mineralogy similar to the porphyritic granite but has distinctly finer ground mass size and less phenocrysts. 3. Trondjhemite/albite granite: Leucocratic rock with one feldspar (albite) and one mica (muscovite). Other minerals are quartz, rare biotite, chlorite, wolframite, iron oxides, monazite, fluorite, apatite and tourmaline. 4. Leucogranite/tourmaline granite: Two feldspar and one mica (muscovite) granite, some outcrops have significant amount of tourmaline (more than 1%). Quartz, k-feldspar, albite, tourmaline, muscovite, fluorite, monazite etc. In Rakcham occurrence three variants are identifiable namely 1. porpyritic granite: two feldspar biotite granite, 2. granodiorite and 3. trondjhemite. The latter two variants are subordinate and the major constituent is the porphyritic granite. Magma mingling is indicated by the presence of mafic pillows in the Mandi occurrence (Miller et al. 2001). Mandi Occurrence: In porphyritic granite plagioclase has a range of composition. The larger grains of plagioclase are zoned with core composition (An29) being more calcic than the rim (An23). Finer grained matrix grains are less calcic (An12) and inclusion of plagioclase within K-feldspar is nearly pure albite. Biotite has a high Fe content (Fe/Fe+Mg~ 0.73). The fine grained porphyritic granite has nearly albitic plagioclase and the biotite is more Fe rich (Fe/Fe+Mg~ 0.780). In trondjhemitic granite the Palaeozoic granites and their younger components A study of Mandi and Rakcham granites from the Himachal Himalaya","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"8 1","pages":"82-83"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79351986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural and metamorphic equivalence across theLHS-HHCS contact, Sikkim Himalaya – indicator of post-deformation metamorphism or the wrong MCT?","authors":"Saibal Gupta, S. Mondal","doi":"10.3126/HJS.V5I7.1261","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1261","url":null,"abstract":"HIMALAYAN JOURNAL OF SCIENCES | VOL. 5 | ISSUE 7 (SPECIAL ISSUE) | 2008 59 In the Sikkim Himalaya, the contact between the base of the Lingtse Gneiss (an augen gneiss body at the base of the Higher Himalayan Crystalline Sequence, HHCS) and the metapelitic schists of the Lesser Himalayan Sequence (LHS) has been considered to be the Main Central Thrust (MCT). The region is characterized by an inverted metamorphic sequence, with the index minerals chlorite to sillimanite appearing at progressively at higher structural levels across the sequence. The study has been conducted along the North-Sikkim Highway (NH -31A), and focuses along the contact zone between HHCS and LHS. Structural studies reveal that the contact zone is a ductile shear zone (the MCT zone) dominated by a single penetrative fabric (S2) trending NW-SE and dipping northeast. This corresponds to a second deformation event that affected lithounits on either side of the contact. Since the intersection lineation between the earlier fabric in both units (S1) and S2 is identical, it is inferred that the earlier fabrics in the HHCS and LHS had similar disposition prior to D2 deformation. A third deformation event (D3) is recorded in the mica schists of the LHS, but this is confined to lower structural levels. The late S3 foliation related to this event cuts across the earlier S1 and S2 fabrics in the LHS. Microstructural relationships between the mineral phases and deformation fabrics, and zoning characteristics of garnet indicate a progressive metamorphic history from the syn-D1 to post-D2 period. Peak metamorphic conditions in both the HHCS and the LHS were attained after D2 deformation, and there appears to be no significant difference in the estimated peak P-T (~ 7 Kb, 650°C) across the MCT zone. The pressures and temperatures have been estimated through both conventional thermobarometric techniques and THERMOCALC, and the interpretations cannot be attributed to flaws in the applied methodology, as suggested by some workers. Thus, the estimated conditions are considered to be realistic. The lack of any detectable difference in peak metamorphic conditions that followed D2 deformation in both units may indicate that the entire metamorphic development is independent of and unconnected to, movement along the MCT. Alternatively, it is possible that the observed shear zone does not correspond to the MCT at all, and that the MCT in this sector needs to be relocated. The latter possibility appears to be supported on structural grounds, since the structural orientation of pre-D2 fabrics in the HHCS and LHS are interpreted to be similar. A more comprehensive study is being undertaken across the sequence to confirm one or the other possibility. Structural and metamorphic equivalence across theLHS-HHCS contact, Sikkim Himalaya – indicator of post-deformation metamorphism or the wrong MCT?","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"62 1","pages":"59"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76130484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Landslides in the Kashmir Earthquake of 8th October 2005","authors":"A. Sinvhal, A. D. Pandey, S. Pore","doi":"10.3126/HJS.V5I7.1332","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1332","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1332 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.152-3","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"86 1","pages":"152-153"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78189688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3-D Velocity Structure of the Crust and upper Mantle in Tibet and its Geodynamic Effect","authors":"Zheng Hongwei, He Rizheng, Zhao Dapeng, Li Tingdong, R. Gao","doi":"10.3126/HJS.V5I7.1269","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1269","url":null,"abstract":"The crust and upper mantle structure under Tibet is the direct result of the India plate subducting and colliding with the Eurasian plate. 3-D seismic velocity structure of the crust and upper mantle under Tibet was determined by using the Tomo3D tomography program developed by Prof. Dapeng Zhao (Zhao et al. 1992, 1994). In the tomographic inversion we used 139,021 Pwave arrival times from 9649 teleseismic events recorded by 305 seismic stations. The major results of this study (Zheng 2006) are summarized as follows: 1) The Tibetan crust velocity structure is generally consistent with the surface tectonic features which are oriented nearly eastwest. But the main trend of the velocity anomalies in the upper mantle is generally oriented in the north-south direction. The location of the NNE strike low-velocity zone is consistent with the N-S strike negative aeromagnetic data. 2) Low-velocity anomalies in the crust are clearly visible under the Himalaya Mountain. 3) Our tomographic images show that the Indian lithospheric mantle subducting angles are different under different areas, but their front locations are all beneath the Qiangtang terrain. The tomographic images (Figure 1) along 88°E show that the Indian lithospheric mantle is underthrusting northwards with a dip angle of about 22° beneath the center of Qiangtang terrane at about 34°N latitude, and its frontier has reached to the deep part of the upper mantle. The tomographic images along North-East profile show that the Indian mantle has nearly horizontally underthrusted under the Tibet from Ganges plain to 33°N. Then, the Indian mantle broke off down to the asthenosphere and caused the asthenophere upwelling. The top shows the surface topography. The tectonic lines are the same as those in Figure 1. The middle panel shows tomography. White circles show local earthquake hypocenters. The dash lines indicate the estimated upper and lower boundaries of the subducting Indian lithospheric mantle. The low-left panel shows the P-wave velocity perturbation scale. The low-right panel shows the location of profile AB along 88° E. 4) There is a huge low-velocity body (Wittlinger et al.,1996) which looks like a mantle plume beneath the Qiangtang terrain. Such a prominent low-velocity body is impossible to be the partial melting products. It is speculated to be either the subducted delamination of the Indian lithospheric mantle according to its location and extending depth with Qaidam block holding back the thermal disturbance in the area, and so resulting in higher temperature which begets falling velocity or be the mantle upwelling materials along the surface of Indian lithospheric mantle.","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"9 1","pages":"69-69"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83079369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Present-day E-W extension in the NW Himalaya (Himachal Pradesh, India)","authors":"E. Hintersberger, R. Thiede, M. Strecker, F. Krüger","doi":"10.3126/HJS.V5I7.1268","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1268","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1268 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.67-68","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"15 1","pages":"67-68"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90750730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrology and geochronology of eclogitic and retrograde micas from Tso Morari UHP Complex, Ladakh Himalaya","authors":"I. Villa, J. Sigoyer, S. Guillot","doi":"10.3126/HJS.V5I7.1342","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1342","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1342 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.167","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"121 1","pages":"167-167"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89469535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical stratigraphic variations and sedimentation model of the Lower Siwalik sequence in Kumaun Himalaya, India","authors":"Uk Shukla, D. Bora","doi":"10.3126/HJS.V5I7.1324","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1324","url":null,"abstract":"HIMALAYAN JOURNAL OF SCIENCES | VOL. 5 | ISSUE 7 (SPECIAL ISSUE) | 2008 143 Lower Siwalik sequence of Kumaun Himalaya is about 300– 900 m thick and shows characteristic stratigraphic changes in sedimentation pattern. Available magnetostratigraphic dates indicate Late Miocene age. Based on detailed facies analysis four depositional settings are identified namely Sandstone Succession (Channel deposits), Mudstone Succession (Floodplain deposits), Mottled Mudstone Succession (Palaeosols), and Mottled Siltstone Succession (Interfluve deposits). Stratigraphic succession shows systematic changes of facies association, palaeocurrent and petrography and palaeochannel patterns. Starting from base, about 500 m thick, coarsening upward Megacycle A is internally made up of two Mesocycles I and II. The sequence is made up of meandering and anastomosing rivers towards the base (Mesocycle I) that gradually evolve into braided towards top (Mesocycle II). This megacycle indicates sedimentation in a narrow subsiding basin by prograding mega fans. The Megacycle evolved under initially more pronounced tectonic activation in the source Vertical stratigraphic variations and sedimentation model of the Lower Siwalik sequence in Kumaun Himalaya, India","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"1 1","pages":"143"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89780480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Degree of Magnetic anisotropy as a strain intensity gauge: An example from the Footwall of MCT Zone along Bhagirathi valley, Garhwal Himalaya, India","authors":"N. R. Tripathy, T. Singh","doi":"10.3126/HJS.V5I7.1341","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1341","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1341 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.164","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"29 1","pages":"164-166"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89793930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Tectonics of the Tso Morari Ultra High Pressure Nappe in Ladakh, NW Indian Himalaya","authors":"A. Steck, J. Epard","doi":"10.3126/HJS.V5I7.1337","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1337","url":null,"abstract":"A tectonic model for the structural development of the Tso Morari ultra-high pressure nappe is proposed. It is integrated into the context of the formation of the North Himalayan nappes of the Ladakh Himalaya. In the area, this stack of nappes is composed by, from base to top, the Tso Morari, Tetraogal, Karzok ophiolite, Nyimaling-Tsarap and Mata nappes (Steck et al. 1998, Steck 2003). Four stretching lineations, L1 – L4, are successively developed on the main schistosity in the North Himalayan nappes (Epard and Steck 2008). L1, with its top-to-the E shear indicators, was formed during the W-directed high temperature extrusion of the ultra high pressure Tso Morari nappe. L2, with its top-to-the S shear indicators, was formed during an early N-directed underthrusting of India below Asia. It is developed in the roof of the Tso Morari nappe as well as at the base and frontal part of the Nyimaling-","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"113 1","pages":"159-160"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88426569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}