| DOI: | 10.1016/j.epsl.2018.02.041
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| Scopus记录号: | 2-s2.0-85043289766
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| 论文题名: | Dating exhumed peridotite with spinel (U–Th)/He chronometry |
| 作者: | Cooperdock E.H.G.; Stockli D.F.
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| 刊名: | Earth and Planetary Science Letters
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| ISSN: | 0012821X
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| 出版年: | 2018
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| 卷: | 489 | | 起始页码: | 219
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| 结束页码: | 227
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| 语种: | 英语
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| 英文关键词: | (U–Th)/He thermochronology
; peridotite
; spinel
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| Scopus关键词: | Computerized tomography
; Lead
; Submarine geology
; Tectonics
; Volcanoes
; Weathering
; Abyssal peridotites
; Detachment faulting
; Passive continental margin
; peridotite
; Slow-spreading ridges
; spinel
; Thermochronology
; X-ray computed tomography
; Volcanic rocks
; cooling
; exhumation
; peridotite
; petrology
; spinel
; tectonic setting
; thermochronology
; uranium series dating
; New Mexico
; United States
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| 英文摘要: | The timing of cooling and exhumation of mantle peridotites in oceanic and continental settings has been challenging to determine using traditional geo- and thermochronometric techniques. Hence, the timing of the exhumation of mantle rocks to the Earth's surface at mid-ocean ridges, rifted and passive continental margins, and within continental volcanic and orogenic systems has remained largely elusive or only loosely constrained by relative age bracketing. Magmatic spinel [(Mg, Fe)(Al,Cr)2O4] is a ubiquitous primary mineral phase in mantle peridotites and is often the only primary mineral phase to survive surface weathering and serpentinization. This work explores spinel (U–Th)/He thermochronology as a novel tool to directly date the exhumation and cooling history of spinel-bearing mantle peridotite. Samples were chosen from a range of tectonic and petrologic settings, including a mid-ocean ridge abyssal peridotite (ODP Leg 209), an orogenic tectonic sliver of sub-continental mantle (Lherz massif, France), and a volcanic-rock hosted mantle xenolith (Green Knobs, NM). Spinel grains were selected based on grain size and morphology, screened for internal homogeneity using X-ray computed tomography, and air abraded to eliminate effects of alpha ejection/implantation. These case studies yield spinel He age results that are reproducible and generally in good agreement with independent age constraints. For ODP Leg 209, a spinel He age of 1.1 ± 0.3 Ma (2 SE) (n=8) is consistent with independent U–Pb and magnetic anomaly ages for the exhumation of oceanic crust by detachment faulting along this segment of the slow-spreading ridge. Spinel from the Lherz massif yield He ages from 60–70 Ma (n=3), which correspond well with independent thermochronometric constraints for cooling associated with Pyrenean collisional exhumation. Spinel from a mantle xenolith within a previously undated kimberlite diatreme at Green Knobs, New Mexico, generate a reproducible mean He age of 11.7 ± 1.8 Ma (2 SE) (n=6) that appears to record young volcanism in the area or age resetting by post-emplacement re-heating or alteration. The combined results of these case studies demonstrate the viability for spinel He thermochronometry to resolve cooling histories of peridotite exhumed through tectonic and volcanic processes. © 2018 Elsevier B.V. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/109969
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| Appears in Collections: | 影响、适应和脆弱性
气候变化事实与影响
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作者单位: | Department of Geological Sciences, The University of Texas, Austin, TX 78712, United States
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| Recommended Citation: | |
Cooperdock E.H.G.,Stockli D.F.. Dating exhumed peridotite with spinel (U–Th)/He chronometry[J]. Earth and Planetary Science Letters,2018-01-01,489
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