Pinnoite Deposit in DaQaidam Saline Lake, Qaidam Basin, China_Hydroclimatic, Sedimentologic, and Geochemical Constraints

doi:10.3390/min8060258

CORC > 青海盐湖研究所 > 中国科学院青海盐湖研究所 > 盐湖地质与环境实验室

	Pinnoite Deposit in DaQaidam Saline Lake, Qaidam Basin, China_Hydroclimatic, Sedimentologic, and Geochemical Constraints
	Yu, JunQing; Hong, Rongchang; Gao, Chunliang; Cheng, Aiying; Zhang, Lisa
刊名	MINERALS
	2018-06
卷号	8 期号:6
ISSN号	2075-163X
DOI	10.3390/min8060258
英文摘要	Mg-borates were traditionally thought to be diagenetic products of other primary borate minerals. Here we report results from the study of pinnoite deposit from DaQaidam saline lake, indicating that pinnoite minerals are primary in origin. Within the detecting limit of X-ray powder diffraction analysis (XRD) analysis, no other borate minerals than pinnoite are detected from the Mg-borate deposit. The cemented pinnoite orebody shows the sedimentary structure of light-dark lamination couplets, which signal marked seasonal variations in brine chemistry. The scanning electronic microscopy coupled with an energy dispersive X-ray spectrometer (SEM-EDX) examination reveals that all pinnoite minerals displayed euhedral, giving no indication of diagenetic origin. A marked shift in lithology from clastic sediment to evaporitic deposit reflects a critical change in sedimentation regime associated with abrupt changes in hydroclimatic conditions. The deposition of the pinnoite ore-layer containing abundant hydromagnesite marked the beginning of the evaporite formation and the end of the clastic deposition. This suggests that aridification occurred abruptly and the saline lake was much more alkaline than today in the early-stage of the evaporite deposition. The intensified summer evaporation and seasonal variations in water chemistry brought about a shallow to nearly desiccated paleo-lake with pH exceeding 9.3, Mg/Ca ratio >39, and boron concentration >600 mg/L, which favored pinnoite precipitation and the formation of pinnoite deposit in the central DaQaidam saline lake.
内容类型	期刊论文
源URL	[http://ir.isl.ac.cn/handle/363002/34412]
专题	青海盐湖研究所_盐湖地质与环境实验室
推荐引用方式 GB/T 7714	Yu, JunQing,Hong, Rongchang,Gao, Chunliang,et al. Pinnoite Deposit in DaQaidam Saline Lake, Qaidam Basin, China_Hydroclimatic, Sedimentologic, and Geochemical Constraints[J]. MINERALS,2018,8(6).
APA	Yu, JunQing,Hong, Rongchang,Gao, Chunliang,Cheng, Aiying,&Zhang, Lisa.(2018).Pinnoite Deposit in DaQaidam Saline Lake, Qaidam Basin, China_Hydroclimatic, Sedimentologic, and Geochemical Constraints.MINERALS,8(6).
MLA	Yu, JunQing,et al."Pinnoite Deposit in DaQaidam Saline Lake, Qaidam Basin, China_Hydroclimatic, Sedimentologic, and Geochemical Constraints".MINERALS 8.6(2018).