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DOI | 10.1016/j.gr.2015.04.009 |
Time constraints on deformation of the Ajjaj branch of one of the largest Proterozoic shear zones on Earth: The Najd Fault System | |
Hassan, M.1,2,5; Stuewe, K.1; Abu-Alam, T. S.3,4,5; Kloetzli, U.6; Tiepolo, M.7 | |
通讯作者 | Hassan, M. |
来源期刊 | GONDWANA RESEARCH
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ISSN | 1342-937X |
EISSN | 1878-0571 |
出版年 | 2016 |
卷号 | 34页码:346-362 |
英文摘要 | In active tectonic regions, shear zones play an important role in re-configuring the structure of the lithosphere. One of the largest shear zones on Earth is the Najd Fault System of the Arabian-Nubian Shield. The main active phase of this shear zone was during the last stages of the Pan-African Orogeny (ca. 630-540 Ma). Six samples of intrusive rocks that were emplaced into the shear zone at different stages during its active phase are used to illustrate the progressive evolution of the Ajjaj shear zone. A sample of coarse-grained diorite, with an intercept U-Pb zircon age of 696 6 Ma, shows very weak deformation. Two samples from deformed granodiorite-tonalite intrusions at the border of the Ajjaj shear zone show conspicuous degrees of deformation, and define two U-Pb clusters of concordia ages at 747 +/- 12 Ma-668 +/- 8 Ma and 742 +/- 5 Ma-702 +/- 12 Ma. Two samples of granites show mylonitic foliation with flattened quartz and biotite parallel to the trend of the shear zone. These samples yield U-Pb ages of 601 +/- 3 Ma-584 +/- 3 Ma. Another granite sample is undeformed and shows crosscutting relations with the shear foliation of the Ajjaj shear zone. It yields a concordia age of 581 +/- 4 Ma. The metamorphic rocks of the Hamadat complex host the Ajjaj shear zone, and have been useful in determining the metamorphic P-T conditions attending the activity of the shear zone. The peak metamorphism of the Hamadat Complex is 505-700 degrees C at two ranges of pressure 8-11 and 14.5 +/- 2 lobar. New data confine the activation of the Ajjaj shear zone in a limited period of time between 604 Ma and 581 Ma and the operation at different crustal levels with a maximum depth of 58 km. (C) 2015 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. |
英文关键词 | U-Pb Zircon Deformation P-T condition Ajjaj shear zone Arabian-Nubian Shield |
类型 | Article |
语种 | 英语 |
国家 | Austria ; Egypt ; Norway ; Italy |
收录类别 | SCI-E |
WOS记录号 | WOS:000384702600023 |
WOS关键词 | ARABIAN-NUBIAN SHIELD ; CORE COMPLEX EXHUMATION ; PB ZIRCON GEOCHRONOLOGY ; CENTRAL EASTERN DESERT ; MC-ICP-MS ; SAUDI-ARABIA ; GEOCHEMICAL CONSTRAINTS ; METAMORPHIC ROCKS ; AFRICAN OROGEN ; TRACE-ELEMENT |
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/2XILL650/193335 |
作者单位 | 1.Graz Univ, Inst Erdwissensch, Univ Pl 2, A-8010 Graz, Austria; 2.Suez Canal Univ, Fac Sci, Dept Geol, Ismailia 41522, Egypt; 3.Norwegian Polar Res Inst, Hjalmar Johansens Gt 14, NO-9296 Tromso, Norway; 4.Tanta Univ, Fac Sci, Dept Geol, Tanta, Egypt; 5.Egyptian Inst Geodynam, Cairo, Egypt; 6.Univ Vienna, Dept Lithospher Res, Althanstr 14, A-1090 Vienna, Austria; 7.UOS Pavia, CNR Ist Geosci & Georisorse, Via Ferrata 1, I-27100 Pavia, Italy |
推荐引用方式 GB/T 7714 | Hassan, M.,Stuewe, K.,Abu-Alam, T. S.,et al. Time constraints on deformation of the Ajjaj branch of one of the largest Proterozoic shear zones on Earth: The Najd Fault System[J],2016,34:346-362. |
APA | Hassan, M.,Stuewe, K.,Abu-Alam, T. S.,Kloetzli, U.,&Tiepolo, M..(2016).Time constraints on deformation of the Ajjaj branch of one of the largest Proterozoic shear zones on Earth: The Najd Fault System.GONDWANA RESEARCH,34,346-362. |
MLA | Hassan, M.,et al."Time constraints on deformation of the Ajjaj branch of one of the largest Proterozoic shear zones on Earth: The Najd Fault System".GONDWANA RESEARCH 34(2016):346-362. |
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