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DOI | 10.1016/S0899-5362(97)00004-3 |
Formation of Neoproterozoic metamorphic core complexes during oblique convergence (Eastern Desert, Egypt) | |
Fritz, H; Wallbrecher, E; Khudeir, AA; ElEla, FA; Dallmeyer, DR | |
通讯作者 | Fritz, H |
会议名称 | Proceedings of the 3rd Meeting of the Mozambique and Related Belts Project |
会议日期 | MAR, 1995 |
会议地点 | JOHANNESBURG, SOUTH AFRICA |
英文摘要 | Major portions of the Pan-African Orogen in the Eastern Desert of Egypt were formed by island-are accretion in the Neoproterozoic. These areas are characterized by their lack of major crustal thickening. Metamorphic core complexes occur parallel to the strike of the Eastern Desert Orogen. These domes exhibit polyphase metamorphism and deformation in contrast to the structurally overlying nappes which include ophiolitic melanges and island-are volcanic rocks. These nappes show northwest directed, orogen-parallel thrusting in the internal parts and west to southwest directed imbrication in the external parts of the orogen. Structures related to exhumation of the metamorphic core complexes partition into different displacement paths localized within a crustal-scale wrench corridor of the Najd fault system. Northwest trending orogen-parallel, sinistral strike-slip faults define the western and eastern margins of the domes. North and south dipping low-angle normal faults developed along the northern and southern margins of the domes and form extensional bridges between them. Ar-40/Ar-39 ages obtained from syntectonic muscovites within the shear zones gave Neoproterozoic ages of 595.9 +/- 0.5 and 588.2 +/- 0.3 Ma. The synchronous activity of strike-slip and normal faults suggests a regional east-west shortening which was accomodated by deep-level basal decollement beneath the metamorphic core complexes and a coeval northwest-southeast, orogen-parallel extension. This extension was accompanied by intramontane molasse sedimentation and emplacement of calc-alkaline plutons. Since the rapid exhumation of gneisses in the core complexes cannot be explained by thickening of the crust, the authors favour a model which calls for enhanced heat flow along the Najd fault system which would have enabled the formation of syn-extensional plutonism and triggered the exhumation of the metamorphic core complexes. Lateral buoyancy forces were concentrated within the Najd wrench corridor and enabled orogen-parallel extension. Copyright (C) 1997 Elsevier Science Ltd. |
来源出版物 | JOURNAL OF AFRICAN EARTH SCIENCES |
ISSN | 1464-343X |
出版年 | 1996 |
卷号 | 23 |
期号 | 3 |
页码 | 311-329 |
出版者 | PERGAMON-ELSEVIER SCIENCE LTD |
类型 | Article;Proceedings Paper |
语种 | 英语 |
国家 | EGYPT;USA |
收录类别 | SCI-E ; CPCI-S |
WOS记录号 | WOS:A1996WL61000004 |
WOS关键词 | ARABIAN-NUBIAN SHIELD ; SAUDI-ARABIA ; PRESSURE ; EVOLUTION ; SYSTEMS ; ROCKS ; TEMPERATURE ; OPHIOLITES ; QUARTZITE ; EXTENSION |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
资源类型 | 会议论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/291587 |
作者单位 | (1)ASSIUT UNIV, DEPT GEOL, ASSIUT, EGYPT;(2)UNIV GEORGIA, DEPT GEOL, ATHENS, GA 30602 USA |
推荐引用方式 GB/T 7714 | Fritz, H,Wallbrecher, E,Khudeir, AA,et al. Formation of Neoproterozoic metamorphic core complexes during oblique convergence (Eastern Desert, Egypt)[C]:PERGAMON-ELSEVIER SCIENCE LTD,1996:311-329. |
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