Late Miocene Intensified Tectonic Uplift and Climatic Aridification on the Northeastern Tibetan Plateau: Evidence From Clay Mineralogical and Geochemical Records in the Xining Basin
SOUTH CHINA SEA
; EAST-ASIAN MONSOON
; NORTH PACIFIC-OCEAN
; TARIM BASIN
; LINXIA BASIN
; QAIDAM BASIN
; PALEOCLIMATIC INTERPRETATION
; STEPWISE ARIDIFICATION
; SEDIMENTARY ARCHIVE
; CENOZOIC EVOLUTION
WOS学科分类:
Geochemistry & Geophysics
WOS研究方向:
Geochemistry & Geophysics
英文摘要:
The uplift of the Tibetan Plateau (TP) during the late Cenozoic is thought to be one of crucial factors controlling Asian climate. However, the complex interaction between tectonics and climate change is still unclear. Here we present the first record of clay mineralogy and elemental geochemistry covering 12.7-4.8Ma in a fluvial-lacustrine sequence in the Xining Basin. Geochemical provenance proxies (Th/Sc, Zr/Sc, and Cr/Zr) in the <2-m fraction show a significant provenance change at 8.8Ma. Silicate-based weathering indexes (CIA, CIW, and PIA) displayed coeval changes with provenance but discrepant changes with regional climate. Since the clay mineralogy exhibits significant change at 7.8Ma uncorrelated with modifications in provenance, it can be employed to reveal regional climate change. The rise in illite and associated decrease in the sum of smectite and illite/smectite mixed layers reflect gradual and slow aridification since 12.7Ma with intensified drying since 7.8Ma until approaching the modern climate status. Our results, together with other regional climatic and tectonic records, clearly illustrate that accelerated uplift of the northeastern TP since 8-9Ma has mainly modulated the regional erosion, weathering, transportation, and sedimentation and amplified the global cooling and drying trend toward the regional climate of modern conditions. Our study suggests that in the tectonically active northeastern TP, a comprehensive mineralogical and geochemical investigation of the fine-grained fraction of the basin sediments could retrieve the interactions between tectonics and climate behind the complex change in exhumed lithology and sedimentary routing systems.
1.Chinese Acad Sci, Inst Tibetan Plateau Res, Key Lab Continental Collis & Plateau Uplift, Beijing, Peoples R China 2.Univ Chinese Acad Sci, Coll Resources & Environm, Beijing, Peoples R China 3.CNRS, UMR7358, Ctr Rech Petrograph & Geochim, Vandoeuvre Les Nancy, France 4.Univ Lorraine, Vandoeuvre Les Nancy, France 5.Chinese Acad Sci, CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing, Peoples R China 6.Lanzhou Univ, Sch Earth Sci, Lanzhou, Gansu, Peoples R China 7.Lanzhou Univ, Key Lab Western Chinas Mineral Resources Gansu Pr, Lanzhou, Gansu, Peoples R China 8.Linyi Univ, Coll Resources & Environm, Linyi, Peoples R China
Recommended Citation:
Yang, Rongsheng,Yang, Yibo,Fang, Xiaomin,et al. Late Miocene Intensified Tectonic Uplift and Climatic Aridification on the Northeastern Tibetan Plateau: Evidence From Clay Mineralogical and Geochemical Records in the Xining Basin[J]. GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,2019-01-01,20(2):829-851