DOI: 10.1038/s41561-020-0640-z
论文题名: Active crustal differentiation beneath the Rio Grande Rift
作者: Cipar J.H. ; Garber J.M. ; Kylander-Clark A.R.C. ; Smye A.J.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2020
卷: 13, 期: 11 起始页码: 758
结束页码: 763
语种: 英语
英文关键词: collapse structure
; continental crust
; differentiation
; extensional tectonics
; granulite
; heat transfer
; lower crust
; partial melting
; thermochronology
; ultrahigh temperature metamorphism
; xenolith
; Mexico [North America]
; Rio Grande Rift
; United States
; Valley of Mexico
英文摘要: Silicon-rich continental crust is unique to Earth. Partial melting during high- to ultrahigh-temperature metamorphism (700 °C to >900 °C) promotes the long-term stability of this crust because it redistributes key elements between the crust and mantle and ultimately produces cooler, more-differentiated continents. Granulites—rocks formerly at high- to ultrahigh-temperature conditions—preserve a record of the stabilization of Earth’s continents, but the tectonic mechanisms that drive granulite formation are enigmatic. Here we present an analysis of lower-crustal xenoliths from the Rio Grande Rift—a nascent zone of extension in the southwestern United States. Uranium–lead geo- and thermochronology combined with thermobarometric modelling show that the lower 10 km of the crust currently resides at granulite-facies conditions, with the lowermost 2 km at ultrahigh-temperature conditions. Crust and mantle xenoliths define a continuous pressure-and-temperature array, indicating that a thin lithospheric mantle lid mediates elevated conductive heat transfer into the crust. These findings establish a direct link among ultrahigh-temperature metamorphism, collapse of the Laramide orogen and lithospheric mantle attenuation. Other indicators of modern ultrahigh-temperature metamorphism are consistent with these conditions prevailing over thousands of square kilometres across the US–Mexico Basin and Range province. Similarities between the pressure-and-temperature path from the Rio Grande lower crust and those from exhumed granulite terranes imply that post-thickening lithospheric extension is a primary mechanism to differentiate Earth’s continental crust. © 2020, The Author(s), under exclusive licence to Springer Nature Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/169573
Appears in Collections: 气候变化与战略
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作者单位: Department of Geosciences, The Pennsylvania State University, University Park, PA, United States; Department of Earth Science, University of California, Santa Barbara, CA, United States
Recommended Citation:
Cipar J.H.,Garber J.M.,Kylander-Clark A.R.C.,et al. Active crustal differentiation beneath the Rio Grande Rift[J]. Nature Geoscience,2020-01-01,13(11)