Windward and leeward margins of an Upper Ordovician carbonate platform in the Central Tarim Uplift, Xinjiang, northwestern China

doi:10.1016/j.palaeo.2016.12.040

	Windward and leeward margins of an Upper Ordovician carbonate platform in the Central Tarim Uplift, Xinjiang, northwestern China
	Zhang, YY (张园园); Li, Y (李越); Wang, G; Munnecke, A
	2017
发表期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN	0031-0182
卷号	474 期号:SI 页码:79-88
摘要	In the Central Uplift of the Tarim Basin, northwestern China, the Katian (Upper Ordovician) limestones of the Lianglitag Formation extend from outcrops in the Bachu area to the subsurface in the Tazhong Oil Field (TZOF) area. Reefs and inner platform deposits are the dominant facies throughout the formation. The reef composition illustrates a palaeoecologic gradient from microbial-dominated buildups on the northwestern margin to metazoan-dominated reefs on the eastern and southern margins of the platform. Between these areas no outcrops are present. In the present study, data including litho- and biofacies logs and correlations from eight wells are presented, six of them of the region between Bachu and Tazhong, and two wells along the former platform margin from the TZOF. Calcimicrobial carbonates are common in core from the inner platform part. Benthic biota documented here resembles that of the microbial mounds and bioclastic limestones in the Bachu outcrop area, and thus is considered as the eastward extension of this realm. However, metazoan-dominated boundstones formed by corals, stromatoporoids, sponges together with calcareous algae are abundant along the southern platform margin, and are similar in composition to the reefs of TZOF in the easternmost part of the platform. The palaeoecologic differentiation between microbial- and metazoan-dominated reefs suggests a strong environmental gradient from a well-oxygenated windward eastern and southern side of the platform, which favoured the open ocean and which was dominated by metazoan reefs, and the inner platform as well as the northwestern, leeward margin of the platform with warmer, less-oxygenated water, which favoured the growth of microbial carbonates. Assuming the trade winds as cause for the contrasting facies on both sides of the platform a palaeo-position of Tarim south of the ITCZ seems probable because a position north of it would require a post Ordovician clockwise rotation of Tarim of about 90 which is possible but less probable. Crown Copyright (C) 2017 Published by Elsevier B.V. All rights reserved.
关键词	Palaeoecologic gradient Palaeogeographic implication Metazoan reef Microbialite Lianglitag Formation
DOI	10.1016/j.palaeo.2016.12.040
收录类别	SCI
语种	英语
WOS研究方向	Physical Geography ; Geology ; Paleontology
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary ; Paleontology
WOS记录号	WOS:000399261500008
出版者	ELSEVIER SCIENCE BV
文献类型	期刊论文
条目标识符	http://ir.nigpas.ac.cn/handle/332004/13638
专题	中国科学院南京地质古生物研究所中国科学院南京地质古生物研究所其他
通讯作者	Zhang, YY (张园园)
推荐引用方式 GB/T 7714	Zhang, YY ,Li, Y ,Wang, G,et al. Windward and leeward margins of an Upper Ordovician carbonate platform in the Central Tarim Uplift, Xinjiang, northwestern China[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2017,474(SI):79-88.
APA	Zhang, YY ,Li, Y ,Wang, G,&Munnecke, A.(2017).Windward and leeward margins of an Upper Ordovician carbonate platform in the Central Tarim Uplift, Xinjiang, northwestern China.Palaeogeography, Palaeoclimatology, Palaeoecology,474(SI),79-88.
MLA	Zhang, YY ,et al."Windward and leeward margins of an Upper Ordovician carbonate platform in the Central Tarim Uplift, Xinjiang, northwestern China".Palaeogeography, Palaeoclimatology, Palaeoecology 474.SI(2017):79-88.