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 Rive...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.展开更多
Bedload transport in alluvial channels has been extensively studied and different equations based on field and/or experimental data have been proposed.Prediction of bed-load transport rate using different equations re...Bedload transport in alluvial channels has been extensively studied and different equations based on field and/or experimental data have been proposed.Prediction of bed-load transport rate using different equations results in wide ranges which are not always reliable.In this study,some of the universal bedload predictors were evaluated with measured load by a Helley-Smith sampler in the Node River,a gravel bed river in the northeast part of Iran.From 19 sets of data,14 series of data were used to evaluate the bed-load transport equations.The results show that the equations presented by Van Rijn,Meyer-Peter and Mueller,and Ackers and White may adequately predict bedload transport in the range of field data.展开更多
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。
文摘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.
文摘Bedload transport in alluvial channels has been extensively studied and different equations based on field and/or experimental data have been proposed.Prediction of bed-load transport rate using different equations results in wide ranges which are not always reliable.In this study,some of the universal bedload predictors were evaluated with measured load by a Helley-Smith sampler in the Node River,a gravel bed river in the northeast part of Iran.From 19 sets of data,14 series of data were used to evaluate the bed-load transport equations.The results show that the equations presented by Van Rijn,Meyer-Peter and Mueller,and Ackers and White may adequately predict bedload transport in the range of field data.
