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DOI | 10.1016/j.lithos.2008.12.014 |
Geochemistry and tectonic evolution of the Neoproterozoic Wadi Ghadir ophiolite, Eastern Desert, Egypt | |
El-Rahman, Yasser Abd1,2; Polat, Ali1; Dilek, Yildirim3; Fryer, Brian1,4; El-Sharkawy, Mohamed2; Sakran, Shawki2 | |
通讯作者 | El-Rahman, Yasser Abd |
来源期刊 | LITHOS
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ISSN | 0024-4937 |
EISSN | 1872-6143 |
出版年 | 2009 |
卷号 | 113期号:1-2页码:158-178 |
英文摘要 | We report new geochemical data from the Neoproterozoic ophiolite in the Wadi Ghadir area, Eastern Desert, Egypt. The Wadi Ghadir ophiolite (WGO) is composed of layered and isotropic gabbros and amygdaloidal to porphyritic pillow lavas. Both the gabbroic rocks and the pillow lavas are intruded by dike swarms with different chemical affinities and spatial orientations. The WGO occurs in an ophiolitic melange (Wadi Ghadir melange, WGM), and both the WGO and WGM are intruded by granitic rocks to the west. On the basis of Zr and Y variations, units of the WGO are classified as tholeiites (e.g., gabbros, amygdaloidal pillow lavas, D1, and D3 dikes).The late-stage D4 dikes show a calc-alkaline affinity, whereas porphyritic pillow lavas and D2 dikes have a transitional character. All ophiolitic units display subduction zone trace element signatures characterized by the enrichment of LILE over HFSE and negative Nb-Ta anomalies. Tholeiitic rocks are further divided into LREE-depleted (gabbros, D3 dikes) and LREE-enriched (amygdaloidal pillow lavas, D1 dikes) groups. Light REE-depleted tholeiitic rocks were derived from melting of a slightly depleted mantle source, whereas the LREE-enriched tholeiitic rocks were derived from a fertile N-MORB source. Calc-alkaline D4 dikes are characterized by steep REE patterns and have low Zr/Nb ratios (23-29), indicating melt contribution from an enriched mantle source, such as sub-continental lithospheric mantle and/or garnet peridotite. The transitional group has LREE-enriched patterns, but its degree of REE enrichment and Zr/Nb ratios are intermediate between the tholeiitic and calc-alkaline groups. The WGO is interpreted to have formed in a back-arc setting behind the Nugrus volcanic arc developed above a NE-clipping subduction zone. The collision of this arc-back-arc system with the passive margin of the Nubian shield (Hafafit dome) resulted in the accretion of the Nugrus arc and the WGO onto the Nubian continental margin and in the initiation of a new subduction zone dipping SW beneath the newly accreted arc-back-arc crust and Hafafit dome. The establishment of this new Andean-type continental margin produced the calc-alkaline D4 dikes, leucogabbros and granitoid plutons intrude the Hafafit dome, the WGO, and the ophiolitic melange. (C) 2009 Elsevier B.V. All rights reserved. |
英文关键词 | Ophiolites Ophiolitic melange Back-arc basin Active continental margin Arabian-Nubian Shield Egypt |
类型 | Article |
语种 | 英语 |
国家 | Canada ; Egypt ; USA |
收录类别 | SCI-E |
WOS记录号 | WOS:000272370500009 |
WOS关键词 | BACK-ARC BASIN ; ISUA GREENSTONE-BELT ; NUBIAN SHIELD ; FRACTIONAL CRYSTALLIZATION ; PROTEROZOIC OPHIOLITES ; ELEMENT MOBILITY ; VOLCANIC-ROCKS ; LOW-TI ; ZONE ; PETROGENESIS |
WOS类目 | Geochemistry & Geophysics ; Mineralogy |
WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/161895 |
作者单位 | 1.Univ Windsor, Dept Earth & Environm Sci, Windsor, ON N9B 3P4, Canada; 2.Cairo Univ, Dept Geol, Giza 12613, Egypt; 3.Miami Univ, Dept Geol, Oxford, OH 45056 USA; 4.Univ Windsor, Great Lake Inst Environm Res, Windsor, ON N9B 3P4, Canada |
推荐引用方式 GB/T 7714 | El-Rahman, Yasser Abd,Polat, Ali,Dilek, Yildirim,et al. Geochemistry and tectonic evolution of the Neoproterozoic Wadi Ghadir ophiolite, Eastern Desert, Egypt[J],2009,113(1-2):158-178. |
APA | El-Rahman, Yasser Abd,Polat, Ali,Dilek, Yildirim,Fryer, Brian,El-Sharkawy, Mohamed,&Sakran, Shawki.(2009).Geochemistry and tectonic evolution of the Neoproterozoic Wadi Ghadir ophiolite, Eastern Desert, Egypt.LITHOS,113(1-2),158-178. |
MLA | El-Rahman, Yasser Abd,et al."Geochemistry and tectonic evolution of the Neoproterozoic Wadi Ghadir ophiolite, Eastern Desert, Egypt".LITHOS 113.1-2(2009):158-178. |
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