Composition and construction of high- and low-energy ooid shoals and their relationships with environmental changes: A case study from the Cambrian Zhangxia Formation in the Ordos Basin， North China
出 版 物：《Journal of Earth Science》 (地球科学学刊(英文版))
年 卷 期：2020年
核心收录：
学科分类：070904[理学-构造地质学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学]
基 金：National Natural Science Foundation of China (No. 41290260 and 41872034)
摘 要：On the basis of systematic study of sedimentary facies， microfacies and geochemistry of measured strata sections and wells， the ooid shoals of the Cambrian Miaolingian Zhangxia Formation in the southern Ordos Basin are composed of high- and low-energy ooid shoals. The characteristics of the high-energy shoals are sparry cementation， with moderate to well sorting， large grain size， high ooid content and low micrite， weak micritization， and well-preserved internal textures of the ooids. Macroscopically， the high-energy ooid shoals display a thick-bedded aggradational stacking pattern in upward coarsening and thickening sequences. The low-energy ooid shoals are mainly made up of micritic cementation， with moderate to poor sorting， relatively small grain size， lower ooid content and higher micrite， strong micritization， and poorly-preserved internal textures of the ooids. Macroscopically， the low-energy ooid shoals show a thin-bedded， interbedded stacking pattern in upward fining and thinning sequences. The sedimentological evidence and carbon isotope data show that the differences of internal fabric and sedimentary evolution of high- and low-energy ooid shoals are closely related to the changes of sea levels.
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