Paleoclimatic and provenance implications of magnetic parameters from the Miocene sediments in the Subei Basin  

作　　者：YouSheng Li JiMin Sun ZhiLiang Zhang Bai Su ShengChen Tian MengMeng Cao 

机构地区：[1]Key Laboratory of Cenozoic Geology and Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [2]Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100101,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Earth and Planetary Physics》2020年第3期308-316,共9页地球与行星物理（英文版）

基　　金：the National Nature Science Foundation of China(grants 41888101);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20070202).

摘　　要：Thick sediments from foreland basins usually provide valuable information for understanding the relationships between mountain building,rock denudation,and sediment deposition.In this paper,we report environmental magnetic measurements performed on the Miocene sediments in the Subei Basin,northeastern Tibetan Plateau.Our results show two different patterns.First,the bulk susceptibility and SIRM,ARM,and HIRM mainly reflect the absolute-concentration of magnetic minerals;all have increased remarkably since 13.7 Ma,related to provenance change rather than climate change.Second,the ratios of IRM100mT/SIRM,IRM100mT/IRM30mT,and IRM100mT/IRM60mT,together with the redness and S ratio,reflect the relative-concentration of hematite,being climate-dependent.Their vertical changes correlate in general with the long-term Miocene climatic records of marine oxygen isotope variations,marked by the existence of higher ratios between 17 and 14 Ma.This may imply that global climate change,rather than uplift of the Tibetan Plateau,played a dominant role in the long-term climatic evolution of the Subei area from the early to middle Miocene.

关 键 词：Environmental magnetism MMCO global cooling the Subei Basin 

分 类 号：P534.62[天文地球—古生物学与地层学] P532[天文地球—地质学] P512.2