Eolian versus fluvial supply to the northern Arabian Sea during the Holocene based on Nd isotope and geochemical records  

作　　者：Waliur Rahaman N.Lathika Priyesh Prabhat Mohd.Tarique K.S.Arya Ravi Mishra Meloth Thamban 

机构地区：[1]National Centre for Polar and Ocean Research,Ministry of Earth Sciences,Goa 403802,India [2]Kerala University of Fisheries and Ocean Studies,Cochin 682506,Kerala,India

出　　处：《Geoscience Frontiers》2023年第5期280-294,共15页地学前缘（英文版）

摘　　要：The north-eastern Arabian Sea(NE-AS)comes under a strong influence of land–ocean–climate interactions and regulates biogeochemical processes through the supply of huge amounts of dissolved and particulate materials and nutrients via eolian and fluvial supply.These processes underwent dramatic changes in the coastal regions due to sea-level rise and climate change during the Holocene;however,their relative roles remain elusive.The NE-AS receives large amounts of dissolved and particulate fluxes,and therefore,reconstruction of the past surface water Nd isotope composition(eNd)and tracing the provenance of sediment using detrital eNd and geochemical records would enable us to assess the role of various processes controlling these fluxes to the northern Arabian Sea.In this study,we have generated authigenic and detrital eNd records and geochemical records in a sediment core from the coastal region of the NE-AS,offshore Saurashtra.We found that the authigenic eNd profile closely followed the Holocene sea-level records;early Holocene less radiogenic values(-8)were sharply shifted to more radiogenic values(-5.5)during the mid-Holocene(6–7 ka)and thereafter remained stable,close to the modern surface water eNd value.The detrital eNd record broadly followed the authigenic eNd record,however,they differ in magnitude.The geochemical records based on major and trace elemental abundances show a similar trend to the authigenic eNd record and concomitant changes with the Holocene sea-level.Our investigation reveals that lower sea-level stand combined with a stronger monsoon during the early Holocene resulted in enhanced fluvial weathering fluxes from the west-flowing rivers and contributed to less radiogenic Nd.This situation changed dramatically during the mid-Holocene due to the weakening of the south-west monsoon and rapid sea level rise,which caused enhanced influence of open ocean water characterised by more radiogenic eNd(-6)derived from the dissolution of dust from Arabia and African desserts.This dramatic shift in

关 键 词：Nd isotopes Circulation Arabian Sea SEA-LEVEL HOLOCENE 

分 类 号：P597.3[天文地球—地球化学] P512.2[天文地球—地质学]