Journal of Himalayan Earth Sciences最新文献

{"title":"Deformation and exhumation of the Higher and Lesser Himalayan Crystalline sequences in the Kumaon region, NW-Himalaya based on structural and fission-track analysis","authors":"R. Patel, N. Lal, Yogesh Kumar","doi":"10.3126/HJS.V5I7.1294","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1294","url":null,"abstract":"The crystalline rocks of the Himalayan orogen, exposed in the Kumaon Himalaya, consist of two distinct high-grade metamorphic units separated by a sequence of meta-sedimentary rocks of the Lesser Himalayan Zone (Figure 1). The northern unit corresponds to the Higher Himalayan Crystalline (HHC) sequence composed mainly of amphibolite facies to migmatitic para-gneiss. At the base, the Main Central Thrust (MCT) (locally named as Munsiari Thrust: MT) bounds the HHC, which is separated from the overlying lowgrade meta-sediments of the Tethyan Sedimentary Zone (TSZ) by a gradational contact. A normal fault, equivalent to the South Tibetan Detachment System (STDS), is demarcated within the upper part of the HHC due to the presence of several normal faults. The southern unit i.e. the Chiplakot Crystalline Belt (CCB) is located within the Lesser Himalayan meta-sedimentary sequence (LHMS) of rocks to the south of the MCT. The North Chiplakot Thrust (NCT) in the north and South Chiplakot Thrust (SCT) in the south separate the CCB from the Lesser Himalayan meta-sedimentary rocks. Both the thrusts dip due NE and join to each other in the west along the Goriganga valley. The LHMS is overriding the CCB along the NCT while the CCB is overriding the LHMS along the SCT. A major NEdipping thrust zone i.e. Central Chiplakot Thrust (CCT) breaks the CCB into two blocks along which the northern block is thrust over the southern block (Kumar and Patel 2004, Patel and Kumar 2006). The CCB mainly consists of greenschist facies rock derived from an early Proterozoic basement. Structural results indicate that both the CCB and the HHC have undergone deformation history of pre-Himalayan (D1) to Himalayan deformations (D2/D3/D4). The prominent penetrative fabric in the CCB and the HHC, developed during the D2 reflect the ductile stage of deformation. It resulted in crustal thickening during Himalayan orogeny and became zone of rapid exhumation. The whole HHC moved along a broad ductile top-to-SW shear zone and the MCT/MT over the LHMS, while the CCB has undergone intense horizontal shortening in a NE-SW direction. It gave rise to the evolution of the CCB by emplacement over the LHMS zone along a broad shear zone developed within the duplex structure that formed south of the MCT (Patel and Kumar 2006). Apatite and zircon fission-track data along the Darma and the Kaliganga valleys along with other published data from the CCB (Patel et al. 2007) and communicated data along the Goriganga valley (Patel and Carter, Communicated to Tectonics) from NW-Himalaya document bedrock cooling histories of the HHC and the CCB units exposed in the Kumaon region. Apatite FT ages range from 0.7±0.2 Ma to 2.9±0.6 Ma along the Goriganga Valley, from 1.0±0.1Ma to 2.8±0.3 Ma along the Darma valley and from 1.4±0.2 Ma to 2.4±0.3 Ma along the Kaliganga valley within the HHC. These show no relationship to either structural position or elevation. The uniform","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"4 1","pages":"101-102"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80136084","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":"Melting and Exhumation of the upper structural levels of the Greater Himalaya Sequence and Makalu granite: constraints from thermobarometry, metamorphic modeling and U-Pb geochronology","authors":"M. Streule, M. Searle, M. Horstwood, David D. Waters","doi":"10.3126/HJS.V5I7.1339","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1339","url":null,"abstract":"The Makalu massif of Eastern Nepal displays a complex suite of Leucogranites and host sillimanite grade gneisses. These leucogranites are linked to the intrusions at the base of the Everest-Lhotse-Nuptse massif immediately to the west (Searle et al 2003) The Makalu intrusion is multiphase and forms the structurally highest foliationparallel sheets of leucogranite along the top of the Greater Himalayan Sequence on the Nepal-Tibet border. It is comprised of massive Grt + Tur + Ms ± Bt leucogranites that also occasionally contain large cordierite crystals. The abundance of cordierite in the upper granite sheet is unlike other granites in the Nepalese Himalaya. The cordierite bearing leucogranite overlies lower sheets of ‘normal’ Himalayan granites intruded into black sillimanite gneisses and is thought to be the most recent phase of magmatism. A few crosscutting feeder dykes mapped adjacent to the upper Barun glacier have channeled magma to the upper sheet. Petrology shows evidence for muscovite dehydration melting (~<700°C) in the upper part of the Barun gneiss which is a likely mechanism by which to produce the Makalu granite melts. Host gneisses retain biotite and so melting temperatures did not exceed 800°C (White et al. 2001). Secondary cordierite rims around garnets in these gneisses and the presence of cordierite in leucogranites record the last low pressure phase of melting. We use these field and petrographic observations for the basis of detailed metamorphic modeling of decompression and geochronology work for the upper parts of the GHS. P-T determinations (THERMOCALCv.3.30) detail peak","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"49 1","pages":"162-162"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90542530","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":"Implications of biostratigraphy in the Himalayan Paleogene Foreland Basin","authors":"S. Bhatia, O. Bhargava","doi":"10.3126/HJS.V5I7.1237","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1237","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1237 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.29-30","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"5 1","pages":"29-30"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86898707","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":"Carbon and sulfur isotope records of Ediacaran carbonates of Lesser Himalayas: implications on oxidative state of the contemporary oceans","authors":"D. Banerjee","doi":"10.3126/HJS.V5I7.1232","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1232","url":null,"abstract":"High resolution geochemical data from fossil-poor Blaini-Krol and fossiliferous Lower Tal succession in the Lesser Himalayas closely conform to the geochemical trends demonstrated by the rock sequences at Oman, Newfoundland, South China and Western United States. Geochemistry of all these known Ediacaran sections suggest long term oxidation of the terminal Proterozoic oceans which led to gradual depletion of dissolved organic carbon reservoir. It is interpreted that the increase in the dissolved organic carbon was responsible for the radiation of acritarchs and algal population (McFadden et al 2008). Such coupling of oceanic oxidation event and the evolution of organisms can be suggested only when chemostratigraphy is adequately supported by biostratigraphy. Lower Himalayan sections do not offer such an opportunity due to low suphate but high sulfide contents in the Krol carbonates and the consequent paucity of preserved organic life in these strata. The Krol basin carbonates show fairly stable organic carbon isotopes, but three profound negative carbonate carbon excursions and a positive excursion close to the rock junction of Lower Tal phosphorite. Two of these excursions are associated with facies changes, hence suspected to be artifacts, while one negative excursion in the transgressive facies represent biogeochemical anomaly co relatable through different continents (Kaufmann et al. 2006). On the other hand, sulfate sulfur isotopes associated with the carbonates are compatible with large buffered dissolved organic carbon reservoir and low sulfate concentrations but high sulfide sulfur. Sharp negative isotopic shift in the upper part of the Krol succession therefore records pulsed oxidation of the deep oceanic dissolved organic carbon reservoir, leading to sudden proliferation of small Shelly Fossils and associated eukaryotic diversity in the Lower Tal phosphate/Chert which follow the sharp negative carbonate carbon excursion. Two negative excursions in the lower Cambrian Tal succession reflect changes in the oceanic chemistry while one small excursion is an artifact and influenced by the facies. On the other hand, at the bottom of the whole succession, representing the end phase of the Blaini Formation, a prominent negative carbonate carbon excursion has matching trends in most of the continents and reflects last phase of the glacial activity in the terminal Proterozoic time.","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"22 1","pages":"21-21"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82802138","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":"Lateral heterogeneity in lithospheric structure in SE Tibet","authors":"A. Meltzer, B. Zurek, S. Sol, Lucy Brown","doi":"10.3126/HJS.V5I7.1284","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1284","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1284 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.90","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"103 1","pages":"90-90"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83048056","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":"Late Quaternary climatic changes in the eastern Kumaun Himalaya, India as deduced from multi-proxy studies","authors":"B. Kotlia, J. Sanwal, B. Phartiyal, L. Joshi, Anjali Trivedi, C. Sharma","doi":"10.3126/HJS.V5I7.1277","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1277","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1277 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.81","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"1 1","pages":"81-81"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88188339","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":"Complex Seismic Discontinuities in the Mantle Transition Zone beneath NW Himalaya and Ladakh- Karakoram","authors":"K. Prakasam, S. S. Rai, K. Priestley, V. Gaur","doi":"10.3126/HJS.V5I7.1298","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1298","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1298 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.108","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"5 1","pages":"108-108"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81555495","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":"Identification of necessary conditions for supershear wave rupture speeds: Application to Californian and Asian Fault","authors":"David L. Robinson, Shamita Das","doi":"10.3126/HJS.V5I7.1311","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1311","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1311 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.125","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"479 1","pages":"125-125"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73642110","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":"Active tectonics and origin of Tso Morari Lake observed by Remote sensing and GIS techniques","authors":"C. Dubey, D. Shukla","doi":"10.3126/HJS.V5I7.1251","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1251","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1251 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.47-48","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"43 1","pages":"47-48"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82023747","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":"Miocene exhumation of the granulite-eclogite of the Ama Drime range (high Himalayas) through polyphased syn-convergence normal faulting","authors":"P. Leloup, E. Kali, N. Arnaud, G. Mahéo, E. Boutonnet","doi":"10.3126/HJS.V5I7.1283","DOIUrl":"https://doi.org/10.3126/HJS.V5I7.1283","url":null,"abstract":"DOI = 10.3126/hjs.v5i7.1283 Himalayan Journal of Sciences Vol.5(7) (Special Issue) 2008 p.89","PeriodicalId":42873,"journal":{"name":"Journal of Himalayan Earth Sciences","volume":"4 1","pages":"89-89"},"PeriodicalIF":0.4,"publicationDate":"2008-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85650141","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}