气候变化领域集成服务门户(CCPortal): Evaluating the potential of soil bacterial tetraether proxies in westerlies dominating western Pamirs, Tajikistan and implications for paleoenvironmental reconstructions

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DOI	10.1016/j.chemgeo.2020.119908
	Evaluating the potential of soil bacterial tetraether proxies in westerlies dominating western Pamirs, Tajikistan and implications for paleoenvironmental reconstructions
	Chen, Chihao; Bai, Yan; Fang, Xiaomin; Zhuang, Guangsheng; Khodzhiev, Amriddin; Bai, Xiaojing; Murodov, Azamdzhon
通讯作者	Bai, Y (通讯作者)
发表日期	2021
ISSN	0009-2541
EISSN	1872-6836
卷号	559
英文摘要	The widely distributed paleoclimate archives in Tajikistan, such as loess-paleosol sequences and the fluvial and lacustrine sedimentary rocks, are excellent materials for studying the aridification histories and mechanisms of the westerlies and the uplift of the Pamirs. The branched glycerol dialkyl glycerol tetraethers (brGDGTs)-based proxies have been increasingly used to reconstruct the paleoenvironmental parameters, e.g., paleo-pH, paleotemperature and paleoaltitude, from sedimentary records and represent potential tools to address the above issues. However, a knowledge of the applicability and factors affecting brGDGT-based proxies remains incomplete, especially in westerlies-dominating areas. Here, we present results from a study with 53 surface soils that are collected along altitudinal transects in the windward slope of the western Pamirs, Tajikistan with large environmental parameter gradients (mean annual air temperature (MAT) varying from - 5.1 to 12.6 degrees C; mean annual precipitation (MAP) spanning a range from 135 to 882 mm; pH ranging from 5.9 to 8.9; soil water content (SWC) changing from 0.102 to 0.183 m(3)/m(3)). The proxies (CBT5ME, IR6ME, CBT' and IBT) show significant correlations with measured pH values (r(2) = 0.51, 0.52, 0.51 and 0.53, respectively), implying the great potential of these proxies for pH reconstructions in Tajikistan. For the alkaline soils, the reconstructed temperature lapse rates (TLR) are constrained to be - 1.0 degrees C/km (actual values ranging from - 4.9 to - 5.4 degrees C /km) using the MAT(mr), a brGDGT-based paleothermometer which is thought to be independent of pH. Similar to the traditional brGDGT-based paleothermometer MBT'/CBT, the anomalies in alkaline soils are related to the fact that pH-dependent 6-methyl brGDGTs are not completely excluded from the calculations in MAT(mr). The paleothermometer which excludes 6-methyl brGDGTs (MBT5ME') is no longer influenced by pH, and records MAT variations along the altitudinal transects for soils lower than similar to 3.3 km. For soils higher than similar to 3.4 km, the correlations between the brGDGT-derived MAT and altitude are statistically significant only in samples with high SWC. However, the calculated MAT and TLR are both overestimated in high SWC samples. Our results suggest that brGDGT-based proxies have the potential to reconstruct palaeoenvironmental parameters in arid and semi-arid Tajikistan with the discretion of the appropriate proxies and calibrations.
关键词	DIALKYL GLYCEROL TETRAETHER QINGHAI-TIBETAN PLATEAU BRANCHED TETRAETHERS LIPID DISTRIBUTION MEMBRANE-LIPIDS EARLY EOCENE DELTA-D MOISTURE TEMPERATURE PALEOTOPOGRAPHY
英文关键词	BrGDGTs; MAT(mr); MBTSME '; Paleotemperature; Paleoaltitude; Paleo-pH
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000600546500012
来源期刊	CHEMICAL GEOLOGY
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/260466
推荐引用方式 GB/T 7714	Chen, Chihao,Bai, Yan,Fang, Xiaomin,et al. Evaluating the potential of soil bacterial tetraether proxies in westerlies dominating western Pamirs, Tajikistan and implications for paleoenvironmental reconstructions[J]. 中国科学院青藏高原研究所,2021,559.
APA	Chen, Chihao.,Bai, Yan.,Fang, Xiaomin.,Zhuang, Guangsheng.,Khodzhiev, Amriddin.,...&Murodov, Azamdzhon.(2021).Evaluating the potential of soil bacterial tetraether proxies in westerlies dominating western Pamirs, Tajikistan and implications for paleoenvironmental reconstructions.CHEMICAL GEOLOGY,559.
MLA	Chen, Chihao,et al."Evaluating the potential of soil bacterial tetraether proxies in westerlies dominating western Pamirs, Tajikistan and implications for paleoenvironmental reconstructions".CHEMICAL GEOLOGY 559(2021).