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Appraisal of active tectonics in Hindu Kush:Insights from DEM derived geomorphic indices and drainage analysis 被引量:20
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作者 Syed Amer Mahmood Richard Gloaguen 《Geoscience Frontiers》 SCIE CAS 2012年第4期407-428,共22页
Landscapes in tectonically active Hindu Kush (NW Pakistan and NE Alghanistanl result from a complex integration of the effects of vertical and horizontal crustal block motions as well as erosion and deposition proces... Landscapes in tectonically active Hindu Kush (NW Pakistan and NE Alghanistanl result from a complex integration of the effects of vertical and horizontal crustal block motions as well as erosion and deposition processes. Active tectonics in this region have greatly influenced the drainage system and geomorphic expressions. The study area is a junction of three important mt^unlain ranges (Hindu Kush-Karakorunl-Himalayas) and is thus an ideal natural laboratory to investigate the relative tectonic activity resulting from the India-Eurasia collision. We evaluate active tectonics using DEM derived drainage network and geomorphic indices hypsometric integral (Hl). stream-length gradient (SL), fractal dimension (FD), basin asymmetry factor (AF), basin shape index (B,), valley floor width to wllley height ratio (Vf) and motmtain front sinuosity (Star). The results obtained from these indices were combined to yield an index of relative active tectonics (IRAT) using GIS. The average of the seven measured geomorphic indices was used to ewfluate the distri- bution of relative tectonic activity in the study area. We defined tour classes to define the degree of rela- tive tectonic activity: class 1 very high (1.0 ≤ IRAT 〈 1.3); class 2 high (1.3 ≥ IRAT 〈 1.5): class 3--moderate (1.5 〉 IRAT 〈 1.8); and class 4--low (1.8 〉 IRAT). In view of the results, we conclude that this combined approach allows the identification of the highly deformed areas related to active tectonics. Landsat imagery and field observations also evidence the presence of active tectonics based on the deflected streams, deformed landforms, active mountain fronts and triangular facets. The indicative values of IRAT are consistent with the areas of known relative uplift rates, landforms and geology. 展开更多
关键词 Active tectonics:Geomorphic indices:IRAT (index of relativeactive tectonics):Hindu Kush:Pakistan--Alghanistan
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The 144–140 Ma Mafic Dykes in North China and Northeast China Indicating Regional Extensional Tectonic Setting 被引量:1
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作者 XU Huan LIU Yongqing +1 位作者 KUANG Hongwei PENG Nan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第1期353-354,共2页
Objective Previous studies indicate that the North China Craton(NCC)had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle(the destruction of... Objective Previous studies indicate that the North China Craton(NCC)had undergone the loss of thickened lithosphere and fundamental change of physical and chemical property of lithospheric mantle(the destruction of NCC)during the Mesozoic.The peak period of the destruction of NCC is estimated to be 130 Ma,accompanied by widespread metamorphic core complex,rift basins,A-type granites and mafic dykes. However, it remains greatly controversial on the tectonic setting of NCC in the pre- 130Ma. 展开更多
关键词 NCC Ma Mafic Dykes in North China and Northeast China Indicating Regional Extensional tectonic Setting The 144 SHRIMP
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Quaternary tectonic control on channel morphology over sedimentary low land:A case study in the Ajay-Damodar interfluve of Eastern India 被引量:3
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作者 Suvendu Roy Abhay Sankar Sahu 《Geoscience Frontiers》 SCIE CAS CSCD 2015年第6期927-946,共20页
The style of active tectonic on the deformation and characterization of fluvial landscape has been investigated on three typical skrike-slip fault zones of the Ajay-Damodar Interfluve(ADI) in Eastern India through f... The style of active tectonic on the deformation and characterization of fluvial landscape has been investigated on three typical skrike-slip fault zones of the Ajay-Damodar Interfluve(ADI) in Eastern India through field mapping,structural analysis and examination of digital topography(ASTER-30 m),multispectral imageries,and Google Earth images,Channel morphology in Quaternary sediment is more deformed than Cenozoic lateritic tract and igneous rock system by the neotectonic activities,The structural and lithological controls on the river system in ADI region are reflected by distinct drainage patterns,abrupt change in flow direction,offset river channels,straight river lines,ponded river channel,marshy lands,sag ponds,palaeo-channels,alluvial fans,meander cutoffs,multi-terrace river valley,incised compressed meander,convexity of channel bed slope and knick points in longitudinal profile,Seven morphotectonic indices have been used to infer the role of neotectonic on the modification of channel morphology,A tectonic index map for the ADI region has been prepared by the integration of used morphotectonic indices,which is also calibrated by Bouguer gravity anomaly data and field investigation. 展开更多
关键词 Active tectonic Skrike-slip fault Channel morphology Morphotectonic indices Neotectonic map
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Quantitative Tectonic Markers of Large Coastal Earthquakes in Fujian, Guangdong, Taiwan and Hainan——with a Discussion of Qualitative Indicators
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作者 Bi Fuzhi Yuan Youshen Institute of Crustal Dynamics, State Seismological Bureau, Beijing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1997年第4期395-406,508-510,共15页
This paper expounds the quantitative tectonic indicators and some qualitative indicators of large earthquakes in the coast areas of Fujian, Guangdong, Taiwan and Hainan. The main quantitative indicators include uplift... This paper expounds the quantitative tectonic indicators and some qualitative indicators of large earthquakes in the coast areas of Fujian, Guangdong, Taiwan and Hainan. The main quantitative indicators include uplift amplitude of the Moho, Quaternary and Late Holocene coasts. The paper also gives a brief account of the research method on quantitative indicators of surface uplifted zones. Taiwan is a famous neotectonic zone and an area of large earthquakes in the world. There is only one large-earthquake area in each of Fujian, Guangdong and Hainan Provinces. Along the coast large earthquake areas there are certainly many remains of crustal activity. Among these remains, coast activity, taking the sea level as the accurate marker horizon, can determine not only the amplitude of coastal elevation and subsidence in a certain period, but also the cycle and rate of positive or negative movements. 展开更多
关键词 quantitative tectonic indicator of large earthquake uplift amplitude of the oho uplift amplitude of the Quaternary high beachrock cycle of coastal large earthquakes
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