A combined tectono-climatic control on Holocene sedimentation in Ladakh Himalaya,India:Clues from Anisotropy of Magnetic Susceptibility(AMS)of lake sediments  

作　　者：B.V.Lakshmi K.Deenadayalan Md.Mujahed Baba Saumitra Misra 

机构地区：[1]Indian Institute of Geomagnetism,New Panvel,Navi Mumbai 410218,India [2]Discipline of Geological Sciences,SAEES,University of KwaZulu-Natal,Durban 4000,South Africa

出　　处：《Journal of Palaeogeography》2024年第4期738-753,共16页古地理学报（英文版）

基　　金：financial support under project DST-WOS-A (SR/WOS-A/ES-15/2010);NRF,South Africa (Grant No.91089 and 150817),for providing necessary funds for this collaborative research work。

摘　　要：Anisotropy of Magnetic Susceptibility(AMS)data from a~27.8 m thick soft sedimentary mud sequence(~10.5-3.25 k yrs)from the Spituk Palaeolake Sequence(SPSS)of Holocene age,located in the northern bank of the Indus River in the Leh-Ladakh Himalaya,show effects of tectonic versus climate dynamics responsible for the Himalayan sedimentation.The sedimentary sequence,consisting of alternating of aeolian sand and glacio-fluvial mud flow deposits,has been subdivided into an older Last Glacier Phase I(LGP 1)and a younger Last Glacier Phase II(LGP 2),where the termination of each phase is marked by the occurrence of gravel beds of thickness≤1 m,which were deposited due to glacial melting.The present AMS data along with previously published information on sedimentology confirm that the mudflow deposits of the LGP 1 and LGP 2phases were deposited in a lacustrine environment under glacio-fluvial conditions.However,a weak fluvial flow towards NW and NE could have existed for the LGP 1 and LGP 2,respectively.The glacial beds terminating LGP 1 and LGP 2 appear to have formed by climatic warming and tectonic activity,respectively.Hence,the Holocene Himalayan sedimentation was influenced by both climatic and tectonic activities.However,the thickness of the gravel bed(~0.8 m)terminating LGP 2 occupies only~2.8 vol%of the total studied thickness~28 m,of the SPSS in the present study,which indicated a lesser control of tectonism in the growth of the Himalaya in and around the study area.

关 键 词：Holocene palaeolake sequence AMS studies Gravel beds DEGLACIATION Tectonic instability 

分 类 号：P512.2[天文地球—地质学] P534.632