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DOI	10.1016/j.epsl.2020.116235
	Experimental stabilization of carbonate sediments to calcite: Insights into the depositional and diagenetic controls on calcite microcrystal texture
	Hashim M.S.; Kaczmarek S.E.
发表日期	2020
ISSN	0012821X
卷号	538
英文摘要	Aragonite and high-magnesium calcite are abundant constituents of modern shallow marine carbonate sediments, but are rare in ancient carbonate rocks. Because these minerals are metastable, they tend to stabilize to microcrystalline calcite which is ubiquitous in most Phanerozoic marine and lacustrine limestones. Calcite microcrystals exhibit a range of textures that have been classified in terms of crystal size, morphology, and contact geometry. These textures have the potential to reveal information about the precursor sediments as well as the diagenetic conditions of stabilization, and thus may serve as a proxy for paleoenvironmental conditions. However, despite their ubiquity and importance, the origin of these textures is controversial. Hypotheses regarding the origin of calcite microcrystal textures typically involve inferences regarding the precursor depositional sediments, diagenetic conditions of stabilization, or diagenetic processes. Here, hundreds of laboratory experiments were conducted in which metastable carbonate sediments were stabilized to calcite. The goal of these experiments was to investigate the depositional and diagenetic controls on calcite microcrystal textures. The depositional variables investigated were precursor mineralogy, type, and size, and the diagenetic variables were temperature, fluid chemical composition, and fluid:solid ratio. Our results show that experimental stabilization of carbonate sediments produces calcite with a wide variety of textures depending on the various depositional and diagenetic parameters. These textures are remarkably similar to those commonly observed in the rock record. Calcite microcrystal morphology is controlled by fluid chemistry, fluid:solid ratio, and reactant type. Calcite microcrystal size is controlled by temperature, fluid chemistry, fluid:solid ratio, and reactant size. The degree to which calcite microcrystals are fitted together is controlled by reactant size and reactant microstructure. Our findings challenge most of the existing hypotheses regarding the origin of calcite microcrystal textures. We specifically show that textures that have been interpreted to indicate late diagenetic processes such as dissolution and cementation, may be the result of the early diagenetic processes of stabilization. © 2020 Elsevier B.V.
关键词	calcite crystal carbonate diagenesis experiment stabilization texture
英文关键词	Calcite; Carbonation; Crystals; Deposition; Experiments; Lime; Morphology; Sediments; Stabilization; Textures; Calcite crystals; Carbonate sediments; Contact geometry; Diagenetic process; Fluid chemicals; Fluid chemistry; Laboratory experiments; Magnesium calcite; Microcrystals; calcite; carbonate sediment; crystal; deposition; diagenesis; limestone; marine sediment; Phanerozoic; texture
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202633
作者单位	Department of Geological and Environmental Sciences, Western Michigan University, Kalamazoo, MI 49008, United States
推荐引用方式 GB/T 7714	Hashim M.S.,Kaczmarek S.E.. Experimental stabilization of carbonate sediments to calcite: Insights into the depositional and diagenetic controls on calcite microcrystal texture[J],2020,538.
APA	Hashim M.S.,&Kaczmarek S.E..(2020).Experimental stabilization of carbonate sediments to calcite: Insights into the depositional and diagenetic controls on calcite microcrystal texture.Earth and Planetary Science Letters,538.
MLA	Hashim M.S.,et al."Experimental stabilization of carbonate sediments to calcite: Insights into the depositional and diagenetic controls on calcite microcrystal texture".Earth and Planetary Science Letters 538(2020).