DOI: 10.1016/j.epsl.2020.116235
论文题名: Experimental stabilization of carbonate sediments to calcite: Insights into the depositional and diagenetic controls on calcite microcrystal texture
作者: Hashim M.S. ; Kaczmarek S.E.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 538 语种: 英语
中文关键词: 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
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165011
Appears in Collections: 气候变化与战略
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作者单位: Department of Geological and Environmental Sciences, Western Michigan University, Kalamazoo, MI 49008, United States
Recommended Citation:
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]. Earth and Planetary Science Letters,2020-01-01,538