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DOI	10.1016/j.epsl.2020.116536
	Carbon ordering in an aseismic shear zone: Implications for Raman geothermometry and strain tracking
	Kedar L.; Bond C.E.; Muirhead D.
发表日期	2020
ISSN	0012821X
卷号	549
英文摘要	Determining the burial and strain history of sedimentary rocks is important for understanding crustal behaviour. When rocks contain organic carbon, increased temperatures at depth can alter the molecular structure of the carbon. This change, known as carbon ordering, can be detected using Raman spectroscopy. As a result, Raman spectroscopy is increasingly used to estimate burial depths and associated maximum temperatures in carbon-bearing rocks. It is known from experiments and natural samples that other factors can affect Raman-derived maximum temperatures, including frictional heating on fault planes and interaction with hot fluids. For faulted samples, a question remains as to whether it is purely frictional heating that causes carbon ordering or strain, or a combination of the two. In this study, we use a mid-crustal shear zone to show that strain-related carbon ordering occurs in natural rock samples during aseismic shear strain. A traverse across the shear zone, whose relative strain we quantify with respect to the surrounding less deformed rock, shows a marked decrease in Raman D/G peak intensity ratios indicating greater carbon ordering within the shear zone. We interpret this as evidence for carbon ordering as a result of aseismic shear strain, rather than inflated temperatures, due to frictional heating commonly associated with seismic strain rates on faults. Our results have implications for the further development of Raman spectroscopy as a geothermometer (which may yield erroneous results in strained rock samples) and for understanding strain localisation processes in the Earth's crust, and its associated rheological implications. © 2020
关键词	geothermometry organic carbon Raman spectroscopy shear zone strain
英文关键词	Friction; Organic carbon; Raman spectroscopy; Sedimentary rocks; Shear strain; Structural geology; Carbon bearing; Frictional heating; Geothermometers; Increased temperature; Maximum temperature; Peak intensity ratio; Seismic strain; Strain localisation; Strain rate; carbon emission; fault plane; geothermometry; Raman spectroscopy; rock mechanics; sedimentary rock; shear strain; shear zone; strain analysis; strain rate
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/202695
作者单位	School of Geosciences, University of Aberdeen, King's College, Aberdeen, AB24 3UE, United Kingdom
推荐引用方式 GB/T 7714	Kedar L.,Bond C.E.,Muirhead D.. Carbon ordering in an aseismic shear zone: Implications for Raman geothermometry and strain tracking[J],2020,549.
APA	Kedar L.,Bond C.E.,&Muirhead D..(2020).Carbon ordering in an aseismic shear zone: Implications for Raman geothermometry and strain tracking.Earth and Planetary Science Letters,549.
MLA	Kedar L.,et al."Carbon ordering in an aseismic shear zone: Implications for Raman geothermometry and strain tracking".Earth and Planetary Science Letters 549(2020).