气候变化领域集成服务门户(CCPortal): Clay mineralogy and geochemistry of the Lower Pleistocene Loess in the Iranian Loess Plateau (Agh Band section) and implications for its provenance and paleoclimate change

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DOI	10.1016/j.quaint.2019.09.011
	Clay mineralogy and geochemistry of the Lower Pleistocene Loess in the Iranian Loess Plateau (Agh Band section) and implications for its provenance and paleoclimate change
	Taheri, Mehdi; Khormali, Farhad; Wang, Xin; Amini, Arash; Landi, Ahmad; Wei, Haitao; Kehl, Martin; Chen, Fahu
通讯作者	Khormali, F (通讯作者)
发表日期	2020
ISSN	1040-6182
EISSN	1873-4553
起始页码	91
结束页码	99
卷号	552
英文摘要	The clay mineralogy and geochemistry of loess is sensitive to variations in sediment source area, transport processes and weathering regime over time, and thus careful study of them can provide some insight into past climate variability. The well-known loess-paleosol sequences (Upper Pleistocene Loess (UPL)) on the Iranian Loess plateau (ILP) are generally underlain by the red deposits consisting of reddish clay to silt-sized sediments of wind-blown origin (Lower Pleistocene Loess (LPL)). Study and analyzing of this oldest brown and reddish brown loess has a specific role in paleoclimate reconstruction but no previous study of the clay mineralogical and geochemical characteristics of them has been performed to date. Therefore, total (Fe-t) and free iron (Fe-d) concentrations and Fe-d/Fe-t ratios, X-ray diffraction as well as geochemical analysis were carried out on a section near the Agh Band village in northeastern province Golestan. Geochemical analysis revealed the same provenance of all deposits in LPL and similarity of them by UPL. X-ray diffraction detected the kaolinite, smectite, chlorite, illite, vermiculite, mica-vermiculite and mica-smectite minerals in the red deposits. The results demonstrated that detrital input is the main source of kaolinite, chlorite and illite, while pedogenic formation during the early Pleistocene could be the dominant cause of smectite and vermiculite occurrences in the LPL. The presence of smectite and vermiculite is in accordance with the xeric and udic soil moisture regime in UPL, respectively. As such it can be concluded that the climate at the time of Agh Band LPL formation varied from semi-arid to sub-humid climate and wetter and more favorable conditions than the overlying late Pleistocene loess and modern soils. These results are confirmed by Al2O3/Na2O, Na2O/K2O, MgO/TiO2 and Fe-d/Fe-t ratios.
关键词	CHINESE LOESS GRAIN-SIZE MAGNETIC-SUSCEPTIBILITY ISOTOPE GEOCHEMISTRY CHEMICAL-COMPOSITION PALEOSOL SEQUENCE DEPOSITS CLIMATE SOILS DUST
英文关键词	Clay mineralogy; Geochemistry; Paleoclimate; Lower Pleistocene loess; Iran
语种	英语
WOS研究方向	Physical Geography ; Geology
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary
WOS记录号	WOS:000573017600002
来源期刊	QUATERNARY INTERNATIONAL
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/260003
推荐引用方式 GB/T 7714	Taheri, Mehdi,Khormali, Farhad,Wang, Xin,et al. Clay mineralogy and geochemistry of the Lower Pleistocene Loess in the Iranian Loess Plateau (Agh Band section) and implications for its provenance and paleoclimate change[J]. 中国科学院青藏高原研究所,2020,552.
APA	Taheri, Mehdi.,Khormali, Farhad.,Wang, Xin.,Amini, Arash.,Landi, Ahmad.,...&Chen, Fahu.(2020).Clay mineralogy and geochemistry of the Lower Pleistocene Loess in the Iranian Loess Plateau (Agh Band section) and implications for its provenance and paleoclimate change.QUATERNARY INTERNATIONAL,552.
MLA	Taheri, Mehdi,et al."Clay mineralogy and geochemistry of the Lower Pleistocene Loess in the Iranian Loess Plateau (Agh Band section) and implications for its provenance and paleoclimate change".QUATERNARY INTERNATIONAL 552(2020).