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DOI | 10.1007/s12517-011-0319-2 |
Pan-African (intraplate and subduction-related?) metasomatism in the Fawakhir ophiolitic serpentinites, Central Eastern Desert of Egypt: mineralogical and geochemical evidences | |
Hamdy, Mohamed M.1; Harraz, Hassan Z.1; Aly, Gehan A.2 | |
通讯作者 | Hamdy, Mohamed M. |
来源期刊 | ARABIAN JOURNAL OF GEOSCIENCES
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ISSN | 1866-7511 |
EISSN | 1866-7538 |
出版年 | 2013 |
卷号 | 6期号:1页码:13-33 |
英文摘要 | Fawakhir serpentinites are the most western ophiolitic ultramafics relative to the Pan-African collision suture at the Qift-Quseir road in the Central Eastern Desert of Egypt. Their location is the basis for their selection in examining the possible contribution of the westerly dipping subducted oceanic slab-related melt/fluid with the intraplate granitic intrusion-related melt/fluid in the metasomatism of the Neoproterozoic ophiolitic serpentinites in the Eastern Desert. Non-residual mineralogy and geochemistry of serpentinites (SF1) far from the post-collision A2-type Fawakhir granitoids and those of serpentinites (SF2) in the vicinity of the granitoid pluton were investigated. The Fawakhir serpentinites are harzburgitic in composition and the Cr# (0.66-0.80) and Mg# (0.32-0.50) of their unaltered spinel cores are indicators for their forearc setting, where they were formed in the oceanic mantle wedge. Based on the spinel Cr# and the whole rock Yb-V bivariate, the melt extraction from the primitive mantle is in excess of 18% up to 24%. The HREE pattern of the SF1 serpentinites refers to the fractional type of melting. The formation of non-residual mineral phases particularly in SF2 samples (amphibole, biotite, apatite thorite, and monazite) and the enrichment of all serpentinites in trace incompatible elements refer to these two serpentinite groups having underwent modal metasomatism. It is suggested that viscous fluid/melt related to the Fawakhir granitoid emplacement metasomatized the SF2 serpentinites, causing a strong enrichment in LREE (display concave LREE; La-N/Sm-N = 3.32-6.25 and U-type HREE; Gd-N/Yb-N = 1.14-2.69) and a slight enrichment in Zr (12-16.62 ppm). All serpentinites are enriched in fluid-mobile elements by aqueous fluids, but the SF2 are more enriched in these elements. The spiked B compared to the other fluid-mobile elements (16.97-24.61 and 42.94-60.66 x PM in SF1 and SF2 samples, respectively) suggests that these elements were added to the obducted ophiolitic Fawakhir serpentinites by the percolation of subduction-related fluids at shallow depths. The contribution of B from shallow continental crust-related fluids is debated. Hosting the Fawakhir serpentinites for the gold deposit at Fawakhir Mine implies a possible genetic relation between gold mineralizations hosted in the ultramafic rocks of the ANS and the processes of recycling of the subducted oceanic slab and the interaction with the mantle. Detailed stable and radiogenic isotopic analyses of the mineralization zones are required to address this question. |
英文关键词 | Geochemistry Mineralogy Fawakhir ophiolitic serpentinites Pan-African orogeny Intraplate and subduction-related fluids/melts Modal metasomatism |
类型 | Article |
语种 | 英语 |
国家 | Egypt |
收录类别 | SCI-E |
WOS记录号 | WOS:000313069000002 |
WOS关键词 | ARABIAN-NUBIAN-SHIELD ; OCEANIC LITHOSPHERIC MANTLE ; FEATHER RIVER OPHIOLITE ; A-TYPE-GRANITOIDS ; MARIANA FORE-ARC ; TRACE-ELEMENT ; ION PROBE ; PETROGENETIC INDICATOR ; ISOTOPIC CONSTRAINTS ; ABYSSAL PERIDOTITES |
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/2XILL650/175808 |
作者单位 | 1.Tanta Univ, Fac Sci, Dept Geol, Tanta 31527, Egypt; 2.Nucl Mat Author, Maadi, Egypt |
推荐引用方式 GB/T 7714 | Hamdy, Mohamed M.,Harraz, Hassan Z.,Aly, Gehan A.. Pan-African (intraplate and subduction-related?) metasomatism in the Fawakhir ophiolitic serpentinites, Central Eastern Desert of Egypt: mineralogical and geochemical evidences[J],2013,6(1):13-33. |
APA | Hamdy, Mohamed M.,Harraz, Hassan Z.,&Aly, Gehan A..(2013).Pan-African (intraplate and subduction-related?) metasomatism in the Fawakhir ophiolitic serpentinites, Central Eastern Desert of Egypt: mineralogical and geochemical evidences.ARABIAN JOURNAL OF GEOSCIENCES,6(1),13-33. |
MLA | Hamdy, Mohamed M.,et al."Pan-African (intraplate and subduction-related?) metasomatism in the Fawakhir ophiolitic serpentinites, Central Eastern Desert of Egypt: mineralogical and geochemical evidences".ARABIAN JOURNAL OF GEOSCIENCES 6.1(2013):13-33. |
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