Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1016/j.jafrearsci.2014.03.022 |
Magnetic fabrics and Pan-African structural evolution in the Najd Fault corridor in the Eastern Desert of Egypt | |
Abdeen, Mamdouh M.1; Greiling, Reinhard O.2; Sadek, Mohamed F.1; Hamad, Sayed S. | |
通讯作者 | Abdeen, Mamdouh M. |
来源期刊 | JOURNAL OF AFRICAN EARTH SCIENCES
![]() |
ISSN | 1464-343X |
EISSN | 1879-1956 |
出版年 | 2014 |
卷号 | 99页码:93-108 |
英文摘要 | In order to assess the Pan-African structural evolution from early orogenic fabrics through Najd wrenching to the latest orogenic collapse/extension, the authors used field work, aided by aerial photographs and satellite images. This work is complemented by the study of the anisotropy of the magnetic susceptibility (AMS, or magnetic fabric). The Pan-African rock associations of the Um Gheig-Kadabora area can be divided into a lower tier composed mainly of amphibolite-migmatite and granitoid gneisses, and an upper tier of ophiolitic rocks, metavolcanics and their related volcaniclastics, and molasse-type Hammamat sediments. Both these units are intruded by late orogenic granitoid plutons and dykes. The lower tier is exposed in a domal structure in the El Sibai area, the upper tier forms a series of weakly to highly deformed thrust units, called Pan-African Nappes here, which are dissected by high strain shear zones. According to their age, these rock units are divided here into early and late-orogenic. The early orogenic rock association is characterized by medium-high metamorphic grades. The late orogenic rock association is characterized by low metamorphic grade. The rocks in the upper tier form a series of low angle thrust sheets, which are bounded by NW-striking high angle shear zones related to the Najd Fault System. The early orogenic rocks show a polyphase structural evolution with early folds, thrusts, and strike-slip shear zones. The late orogenic rocks show a relatively weaker deformation. The latest intrusives studied here are the dykes dissecting the late orogenic Kadabora granite. In the present work magnetic fabric data document the deformational features in detail and assess the role of the Najd Fault System in the deformational evolution. A strong variation in volume susceptibility of various rocks, due to their variations in mineral composition, is observed. Lower values are in the range of 10(-6) SI units for late-orogenic alkaline granite and the dykes dissecting it, the highest susceptibilities exceed 7 x 10(-2) SI units in magnetite-bearing serpentinite. Early orogenic rocks are characterized by relatively high anisotropies (P’ up to 1.7) and are deformed in numerous shear zones. Most of these shear zones can be related to the Najd Fault System. In contrast, late orogenic sediments and intrusives show mostly low anisotropies. However, magnetic lineations are still distinctly oriented parallel with the Najd Fault trend. The very latest Pan-African intrusives, the broadly N-S trending dykes crosscutting the Kadabora pluton, imply c. E-W directed extension. Such an extension is consistent with the magnetic fabric in some of the dykes. Therefore, the Kadabora dykes mark the end of Najd wrenching and a late stage of extension in this part of the Eastern Desert of Egypt. The other dykes display mostly primary fabrics, related to magma flow during their intrusion and are thus post-deformational with regard to the Pan-African orogeny. (C) 2014 Elsevier Ltd. All rights reserved. |
英文关键词 | Arabian-Nubian Shield Pan-African Anisotropy of magnetic susceptibility (AMS) Um Gheig-Kadabora Najd Fault System Late-tectonic extension |
类型 | Article |
语种 | 英语 |
国家 | Egypt ; Germany |
收录类别 | SCI-E |
WOS记录号 | WOS:000345540900008 |
WOS关键词 | ARABIAN-NUBIAN SHIELD ; CORE COMPLEX ; OBLIQUE CONVERGENCE ; TECTONIC EVOLUTION ; SAUDI-ARABIA ; ANISOTROPY ; GEOCHEMISTRY ; SUSCEPTIBILITY ; NAPPES ; PETROGENESIS |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/182881 |
作者单位 | 1.Natl Author Remote Sensing & Space Sci, Cairo, Egypt; 2.Karlsruhe Inst Technol, Inst Angew Geowissensch Strukturgeol & Tektonophy, D-76187 Karlsruhe, Germany |
推荐引用方式 GB/T 7714 | Abdeen, Mamdouh M.,Greiling, Reinhard O.,Sadek, Mohamed F.,et al. Magnetic fabrics and Pan-African structural evolution in the Najd Fault corridor in the Eastern Desert of Egypt[J],2014,99:93-108. |
APA | Abdeen, Mamdouh M.,Greiling, Reinhard O.,Sadek, Mohamed F.,&Hamad, Sayed S..(2014).Magnetic fabrics and Pan-African structural evolution in the Najd Fault corridor in the Eastern Desert of Egypt.JOURNAL OF AFRICAN EARTH SCIENCES,99,93-108. |
MLA | Abdeen, Mamdouh M.,et al."Magnetic fabrics and Pan-African structural evolution in the Najd Fault corridor in the Eastern Desert of Egypt".JOURNAL OF AFRICAN EARTH SCIENCES 99(2014):93-108. |
条目包含的文件 | 条目无相关文件。 |
除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。