干旱区生态环境知识资源中心(Arid): Geochemistry and Petrogenesis of Late Ediacaran Rare-metal Albite Granites of the Arabian-Nubian Shield

Arid

DOI	10.1111/1755-6724.14379
	Geochemistry and Petrogenesis of Late Ediacaran Rare-metal Albite Granites of the Arabian-Nubian Shield
	Abuamarah, Bassam A.; Azer, Mokhles K.; Asimow, Paul D.; Ghrefat, Habes; Mubarak, Heba S.
通讯作者	Abuamarah, BA (corresponding author), King Saud Univ, Dept Geol & Geophys, Riyadh 11451, Saudi Arabia.
来源期刊	ACTA GEOLOGICA SINICA-ENGLISH EDITION
ISSN	1000-9515
EISSN	1755-6724
出版年	2021
卷号	95 期号:2 页码:459-480
英文摘要	The Abu Dabbab albite granite (ADAG), in the central Eastern Desert of Egypt, hosts the most significant rare metal ore deposit in the northern part of the Neoproterozoic Arabian-Nubian Shield. Here, we report detailed field, petrographic, mineralogical and geochemical investigation of the ADAG, an isolated stock-like granitic body with sharp intrusive contacts against metamorphic country rocks, probably emplaced at about 600 Ma. The fine-grained porphyritic upper unit is a preserved remnant of the shallowly-emplaced apex of the magma chamber, whereas the medium-grained lower unit crystallized at deeper levels under subvolcanic conditions. The peraluminous leucocratic ADAG shares common geochemical characteristics with post-collisional intraplate A-type magmas. In addition to the conspicuous enrichment in Na2O, the ADAG is remarkable for its anomalous concentrations of Ta, Nb, Li, Hf, Ga, Sn, Zn and heavy rare-earth elements. Nb-Ta minerals in the ADAG are mixed with Fe-Mn oxides, forming black patches that increase in abundance toward of the base of the intrusion. Columbite-tantalite, cassiterite and wolframite are the most important ore minerals. Pronounced negative Eu anomalies (Eu/Eu* = 0.10-0.24) reflect extreme magmatic fractionation and perhaps the effects of late fluid-rock interaction. The ADAG was most likely generated by partial melting of the juvenile middle crust of the ANS as the geotherm was elevated by erosional uplift following lithospheric delamination and it was emplaced at the intersection of lineations of structural weakness. Although formation of the ADAG and its primary enrichment in rare metals are essentially due to magmatic processes, late-stage metasomatism caused limited redistribution of rare metals. Fluid-driven subsolidus modification was limited to the apex of the magma chamber and drove development of greisen, amazonite, and quartz veins along fracture systems.
英文关键词	amazonite greisen rare-metal bearing granite stockscheider pegmatite tetrad effect post-collisional Arabian-Nubian Shield
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000653317300010
WOS关键词	A-TYPE GRANITES ; EASTERN DESERT ; RING COMPLEX ; TECTONOMAGMATIC EVOLUTION ; BAERZHE GRANITES ; BARREN GRANITES ; EARTH-ELEMENTS ; SOUTHERN SINAI ; PLUTONIC ROCKS ; CALC-ALKALINE
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
来源机构	King Saud University
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/349256
作者单位	[Abuamarah, Bassam A.; Ghrefat, Habes] King Saud Univ, Dept Geol & Geophys, Riyadh 11451, Saudi Arabia; [Azer, Mokhles K.; Mubarak, Heba S.] Natl Res Ctr, Dept Geol Sci, Cairo 12622, Egypt; [Asimow, Paul D.] CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA
推荐引用方式 GB/T 7714	Abuamarah, Bassam A.,Azer, Mokhles K.,Asimow, Paul D.,et al. Geochemistry and Petrogenesis of Late Ediacaran Rare-metal Albite Granites of the Arabian-Nubian Shield[J]. King Saud University,2021,95(2):459-480.
APA	Abuamarah, Bassam A.,Azer, Mokhles K.,Asimow, Paul D.,Ghrefat, Habes,&Mubarak, Heba S..(2021).Geochemistry and Petrogenesis of Late Ediacaran Rare-metal Albite Granites of the Arabian-Nubian Shield.ACTA GEOLOGICA SINICA-ENGLISH EDITION,95(2),459-480.
MLA	Abuamarah, Bassam A.,et al."Geochemistry and Petrogenesis of Late Ediacaran Rare-metal Albite Granites of the Arabian-Nubian Shield".ACTA GEOLOGICA SINICA-ENGLISH EDITION 95.2(2021):459-480.