Clay mineral changes across the Eocene-Oligocene transition in the sedimentary sequence at Xining occurred prior to global cooling

doi:10.1016/j.palaeo.2014.06.031

	Clay mineral changes across the Eocene-Oligocene transition in the sedimentary sequence at Xining occurred prior to global cooling
	Zhang, Chunxia; Guo, Zhengtang
刊名	PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
	2014-10-01
卷号	411 页码:18-29
关键词	Eocene-Oligocene transition Clay minerals Continental record Xining basin
ISSN号	0031-0182
DOI	10.1016/j.palaeo.2014.06.031
文献子类	Article
英文摘要	During the Cenozoic, high-quality long-term sedimentary sequences formed in Xining basin at the northeastern margin of the Tibetan Plateau, which are characterized by alternating gypsiferous layers and reddish mudstone beds. The Tashan section was previously dated in detail by magnetostratigraphy, which yielded an age span of 16 to 35.7 Ma. In this study, bulk and clay mineral assemblages and magnetic parameters of the 33.1-35.7 Ma portion were analyzed using X-ray diffraction and magnetic methods to determine the behavior of the Eocene-Oligocene climate transition. Quartz, calcite, feldspar and clay fractions in sediments that are mainly derived from the surrounding catchments, gypsum and dolomite are authigenic minerals. Illite, chlorite, irregular mixed-layer illite-smectite and smectite are the four main clay-sized fractions (<2 mu m) in the gypsum/gypsiferous layers and the reddish mudstone beds, which suggest that no significant tectonic activity occurred in the catchment area of the Xining basin during the period of 35.7-33.1 Ma. Dominant hematite, illite and gypsum in the sediments indicate that the climate was dominantly hot and dry in the Xining basin. This was controlled by a "planetary" subtropical aridity zonal pattern; the variations in gypsum, dolomite and smectite content are mainly controlled by the climate changes. The characteristics of the clay mineral assemblages suggest that warm and humid fluctuations with hot and dry conditions prevailed during similar to 35.7-34.1 Ma in inner Asia. This changed to cold and dry conditions at similar to 34.1 Ma and remained so from similar to 34.1 to 33.1 Ma. Comparisons with open ocean marine records and Northern Hemisphere continental records indicate that the climate cooling in continental records occurred prior to the main drop of delta O-18 in foraminifera preserved in marine sediments at Oi-1 (33.545 Ma). This demonstrates that the magnitude of Antarctic ice growth during the EOT was not the major contributor to inner Asian aridification, possibly due to the northward moving of subtropical highs that existed in northwest China and was induced by temperate zones moving during the late Eocene to early Oligocene. (c) 2014 Elsevier B.V. All rights reserved.
WOS关键词	CLIMATE TRANSITION ; TIBETAN PLATEAU ; NORTH-AMERICA ; TARIM BASIN ; CHINA ; RECORDS ; EXTINCTIONS ; EVOLUTION ; BOUNDARY ; ATLANTIC
WOS研究方向	Physical Geography ; Geology ; Paleontology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000342269200002
资助机构	Chinese Academy of Sciences(XDB03020500) ; Chinese Academy of Sciences(XDB03020500) ; National Nature Science Foundation of China(41172159) ; National Nature Science Foundation of China(41172159) ; Chinese Academy of Sciences(XDB03020500) ; Chinese Academy of Sciences(XDB03020500) ; National Nature Science Foundation of China(41172159) ; National Nature Science Foundation of China(41172159) ; Chinese Academy of Sciences(XDB03020500) ; Chinese Academy of Sciences(XDB03020500) ; National Nature Science Foundation of China(41172159) ; National Nature Science Foundation of China(41172159) ; Chinese Academy of Sciences(XDB03020500) ; Chinese Academy of Sciences(XDB03020500) ; National Nature Science Foundation of China(41172159) ; National Nature Science Foundation of China(41172159)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84792]
专题	中国科学院地质与地球物理研究所
通讯作者	Zhang, Chunxia
作者单位	Chinese Acad Sci, Inst Geol & Geophys, Key Lab Cenozo Geol & Environm, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Chunxia,Guo, Zhengtang. Clay mineral changes across the Eocene-Oligocene transition in the sedimentary sequence at Xining occurred prior to global cooling[J]. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2014,411:18-29.
APA	Zhang, Chunxia,&Guo, Zhengtang.(2014).Clay mineral changes across the Eocene-Oligocene transition in the sedimentary sequence at Xining occurred prior to global cooling.PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,411,18-29.
MLA	Zhang, Chunxia,et al."Clay mineral changes across the Eocene-Oligocene transition in the sedimentary sequence at Xining occurred prior to global cooling".PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 411(2014):18-29.