DOI: 10.1016/j.epsl.2020.116536
论文题名: Carbon ordering in an aseismic shear zone: Implications for Raman geothermometry and strain tracking
作者: Kedar L. ; Bond C.E. ; Muirhead D.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2020
卷: 549 语种: 英语
中文关键词: 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
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 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165073
Appears in Collections: 气候变化与战略
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作者单位: School of Geosciences, University of Aberdeen, King's College, Aberdeen, AB24 3UE, United Kingdom
Recommended Citation:
Kedar L.,Bond C.E.,Muirhead D.. Carbon ordering in an aseismic shear zone: Implications for Raman geothermometry and strain tracking[J]. Earth and Planetary Science Letters,2020-01-01,549