Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1007/s001260050287 |
Petrological characteristics of podiform chromitites and associated peridotites of the Pan African Proterozoic ophiolite complexes of Egypt | |
Ahmed, AH; Arai, S; Attia, AK | |
通讯作者 | Ahmed, AH |
来源期刊 | MINERALIUM DEPOSITA
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ISSN | 0026-4598 |
EISSN | 1432-1866 |
出版年 | 2001 |
卷号 | 36期号:1页码:72-84 |
英文摘要 | Mafic-ultramafic fragments of a dismembered ophiolite complex are abundant in the late Precambrian Pan African belt of the Eastern Desert of Egypt and north-east Sudan. The ultramafic bodies in the Eastern Desert of Egypt are mostly characterised by the harzburgite-dunite-chromitite association. Because of their severe metamorphism, almost all primary silicates were converted to secondary minerals and we use the chrome spinel as a reliable petrogenetic indicator. The podiform chromitite deposits are common as small and irregularly shaped masses in the central and southern parts of the Eastern Desert. They strongly vary in texture, degree of alteration and chemical composition of chrome spinel. The podiform chromitites exhibit a wide range of composition from high Cr to high Al varieties. The Cr of chrome spinel ranges from 0.65 to 0.85 in dunite, quite similar in the high-Cr chromitite, whereas it is around 0.5 in harzburgite. Primary hydrous mineral inclusions, amphibole and phlogopite, in chrome spinel are reported for the first time from the Pan African Proterozoic podiform chromitites. The petrological characteristics of Pan African podiform chromitites and associated peridotites of Egypt are similar to those of Phanerozoic ophiolites. The Proterozoic podiform chromitites may have formed in the same way as the Phanerozoic ones, namely by melt-harzburgite reaction and subsequent melt mixing. The similarity of the mantle section of the late Proterozoic and the Phanerozoic ophiolites suggests that the thermal conditions controlling genesis of the crust-mantle system basically have not changed since the late Proterozoic era. The Pan African harzburgite is very similar to abyssal peridotite at fast-spreading ridges, and the high-Cr, low-Ti character of spinel in chromitite and dunite indicates a genetic link with a supra-subduction zone setting. The late Proterozoic ophiolites of Egypt are possibly a fragment of oceanic lithosphere modified by are-related magmatic rocks, or a fragment of back-arc basin lithosphere. |
类型 | Article |
语种 | 英语 |
国家 | Japan ; Egypt |
收录类别 | SCI-E |
WOS记录号 | WOS:000166222000006 |
WOS关键词 | COMPOSITIONAL VARIATION ; SPINEL PERIDOTITES ; CHROMIAN SPINEL ; OMAN OPHIOLITE ; FLUID PHASE ; DEPOSITS ; OLIVINE ; RICH ; DISSOLUTION ; INCLUSIONS |
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/2XILL650/141479 |
作者单位 | (1)Kanazawa Univ, Fac Sci, Dept Earth Sci, Kanazawa, Ishikawa 9201192, Japan;(2)CMRDI, Cairo, Egypt |
推荐引用方式 GB/T 7714 | Ahmed, AH,Arai, S,Attia, AK. Petrological characteristics of podiform chromitites and associated peridotites of the Pan African Proterozoic ophiolite complexes of Egypt[J],2001,36(1):72-84. |
APA | Ahmed, AH,Arai, S,&Attia, AK.(2001).Petrological characteristics of podiform chromitites and associated peridotites of the Pan African Proterozoic ophiolite complexes of Egypt.MINERALIUM DEPOSITA,36(1),72-84. |
MLA | Ahmed, AH,et al."Petrological characteristics of podiform chromitites and associated peridotites of the Pan African Proterozoic ophiolite complexes of Egypt".MINERALIUM DEPOSITA 36.1(2001):72-84. |
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