气候变化领域集成服务门户(CCPortal): Miocene C(4)Grassland Expansion as Recorded by the Indus Fan

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DOI	10.1029/2020PA003856
	Miocene C(4)Grassland Expansion as Recorded by the Indus Fan
	Feakins, Sarah J.; Liddy, Hannah M.; Tauxe, Lisa; Galy, Valier; Feng, Xiaojuan; Tierney, Jessica E.; Miao, Yunfa; Warny, Sophie
通讯作者	Feakins, SJ (通讯作者)
发表日期	2020
ISSN	2572-4517
EISSN	2572-4525
卷号	35 期号:6
英文摘要	In the late Miocene, grasslands spread across the forested floodplains of the Himalayan foreland, but the causes of the ecological transition are still debated. Recent seafloor drilling by the International Ocean Discovery Program (IODP) provides an opportunity to study the transition across a larger region as archived in the Indus submarine fan. We present a multiproxy study of past vegetation change based on analyses of the carbon isotopic composition (delta C-13) of bulk organic carbon, plant waxn-alkanes andn-alkanoic acids, and quantification of lignin phenols, charcoal, and pollen. We analyze the hydrogen isotopic composition (delta D) of plant wax to reconstruct precipitation delta D. We use the Branched and Isoprenoid Tetraether (BIT) index to diagnose shifts between terrestrial versus marine lipid inputs between turbidite and hemipelagic sediments. We reconstruct ocean temperatures using the TEX(86)index only where marine lipids dominate. We find evidence for the late Miocene grassland expansion in both facies, confirming this was a regional ecosystem transformation. Turbidites contain dominantly terrestrial matter from the Indus catchment (D-depleted plant wax), delivered via fluvial transport as shown by the presence of lignin. In contrast, hemipelagic sediments lack lignin and bear D-enriched plant wax consistent with wind-blown inputs from the Indian peninsula; these show a 7.4-7.2 Ma expansion of C(4)grasslands on the Indian subcontinent. Within each facies, we find no clear change in delta D values across the late Miocene C(4)expansion, implying consistent distillation of rainfall by monsoon dynamics. Yet, a cooling in the Arabian Sea is coincident with the C(4)expansion.
关键词	C-4 PLANT EXPANSION VEGETATION CHANGE ATMOSPHERIC CO2 ARABIAN SEA ISOTOPIC COMPOSITION LATE QUATERNARY WAX BIOMARKERS CLAY-MINERALS RIVER-BASIN EVOLUTION
英文关键词	International Ocean Discovery Program; Expedition 355; Site U1457; Indus Fan; biomarker
语种	英语
WOS研究方向	Geology ; Oceanography ; Paleontology
WOS类目	Geosciences, Multidisciplinary ; Oceanography ; Paleontology
WOS记录号	WOS:000545646500002
来源期刊	PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/260070
推荐引用方式 GB/T 7714	Feakins, Sarah J.,Liddy, Hannah M.,Tauxe, Lisa,et al. Miocene C(4)Grassland Expansion as Recorded by the Indus Fan[J]. 中国科学院青藏高原研究所,2020,35(6).
APA	Feakins, Sarah J..,Liddy, Hannah M..,Tauxe, Lisa.,Galy, Valier.,Feng, Xiaojuan.,...&Warny, Sophie.(2020).Miocene C(4)Grassland Expansion as Recorded by the Indus Fan.PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY,35(6).
MLA	Feakins, Sarah J.,et al."Miocene C(4)Grassland Expansion as Recorded by the Indus Fan".PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 35.6(2020).