DOI: 10.1016/j.earscirev.2021.103595
论文题名: Structural architecture and Late Cretaceous exhumation history of the Saih Hatat Dome (Oman), a review based on existing data and semi-restorable cross-sections
作者: Hansman R.J. ; Ring U. ; Scharf A. ; Glodny J. ; Wan B.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2021
卷: 217 语种: 英语
英文关键词: architecture
; Cretaceous
; deformation
; exhumation
; obduction
; ophiolite
; P-T conditions
; structural geology
; subduction
; tectonic evolution
; tectonic setting
; Oman
; Oman Mountains
; Saih Hatat
英文摘要: The Saih Hatat Dome in the Al Hajar Mountains provides an outstanding opportunity to study subduction/exhumation processes coeval with obduction of the Semail Ophiolite. The exceptionally good outcrop conditions offer a unique opportunity to constrain the geometry of this subduction/obduction complex. In this review, the metamorphic, structural, and tectonic evolution of the Oman high-pressure complex in the Saih Hatat Dome is discussed. New structural cross-sections are developed and are used to interpret a geometrically feasible tectonic model for the Saih Hatat Dome. Our review highlights the importance of two major tectonic boundaries: (1) The As Sheik Shear Zone which separates the high pressure rocks of the As Sifah Unit (1.7–2.3 GPa and 510–550 °C) from the overlying Hulw Unit (1.0–1.2 GPa and 250–300 °C), and was active at ~79–76 Ma; and (2) the Upper Plate–Lower Plate Discontinuity, which forms a major surface in the landscape and developed by ~76–74 Ma, cutting through structures of the HP rocks in the lower plate (footwall). This discontinuity is associated with a pronounced strain gradient, notably in its upper plate (hanging wall), and separates rocks that have markedly different deformation geometry. The Upper Plate–Lower Plate Discontinuity initiated with a modest dip angle, making it a neutral structure in terms of crustal shortening vs extension. As a result, there is no discernable break in P-T conditions across it. The upper plate is dominated by the Saih Hatat Fold Nappe, forming between ~76 and 70 Ma. Subsequently, the upper plate has been dissected by a number of NNE-dipping thrusts at ~70–66 Ma, followed by normal faults at <~66 Ma. Our review and tectonic model indicate that the Oman high-pressure rocks were exhumed in a contractional tectonic setting that was possibly driven by forced return flow assisted by buoyancy forces. During this exhumation, when the rocks reached the greenschist-facies middle crust the Upper Plate–Lower Plate Discontinuity formed, as a shallow, south-dipping backthrust. Final exhumation of the high-P rocks was achieved by late normal faults after ~66 Ma. © 2021 The Authors Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166413
Appears in Collections: 气候变化与战略
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作者单位: State Key Laboratory of Lithospheric Evolution, Innovation Academy for Earth Science, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; Department of Geological Sciences, Stockholm University, Stockholm, 106 91, Sweden; Department of Earth Sciences, College of Science, Sultan Qaboos University, Muscat; GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany
Recommended Citation:
Hansman R.J.,Ring U.,Scharf A.,et al. Structural architecture and Late Cretaceous exhumation history of the Saih Hatat Dome (Oman), a review based on existing data and semi-restorable cross-sections[J]. Earth Science Reviews,2021-01-01,217