干旱区生态环境知识资源中心(Arid): Extreme fractionation and magmatic-hydrothermal transition in the formation of the Abu Dabbab rare-metal granite, Eastern Desert, Egypt

Arid

DOI	10.1016/j.lithos.2019.105329
	Extreme fractionation and magmatic-hydrothermal transition in the formation of the Abu Dabbab rare-metal granite, Eastern Desert, Egypt
	Zoheir, Basem 1,2; Lehmann, Bernd 3; Emam, Ashraf 4; Radwan, Abdelhady 4; Zhang, Rongqing 5; Bain, Wyatt M.6; Steele-MacInnis, Matthew 6; Nolte, Nicole 7
通讯作者	Zoheir, Basem
来源期刊	LITHOS
ISSN	0024-4937
EISSN	1872-6143
出版年	2020
卷号	352
英文摘要	The Abu Dabbab rare-metal granite in the Central Eastern Desert of Egypt is a peraluminous alkali-feldspar leucogranite stock with minimummelt composition of albite-rich haplogranite and is characterized by economic resources of columbite group minerals (CGM) and cassiterite. The bulk-rock trace element composition is characterized by very low Sr, Ba, REE+Y, Zr, Ti, Ni, Cr concentrations, elevated Li and F, and very high Sn, Ta and Ga. The non-chondritic, low Y/Ho ratios and extremely low Nb/Ta and Zr/Hf ratios of the Abu Dabbab granite are consistent with highly evolved peraluminous granites. The chondrite-normalized REE patterns with significant tetrad effects (TE1,3 similar to 1.6-2.6) and strongly negative Eu anomalies are indicative of the magmatic to hydrothermal transition. Heterogeneous Sm-147/Nd-144 (0.20411-0.51923) and Nd-143/Nd-144 (0.512968-0.514056) values of the bulk-rock reflect a disturbed Sm-Nd isotope system. Nevertheless, the initial epsilon Nd values calculated for a wide range of Neoproterozoic ages (500-700 Ma) are consistently positive, suggesting a juvenile source. Laser ablation ICP-MS analyses of the CGM, cassiterite, wolframite and Mn-ilmenite show elevated rare metal concentrations and complex REE tetrad patterns, reflecting fluid-melt interactions. The metasomatic fluids associated with the Abu Dabbab rare-metal granite were primarily low-salinity (<6 wt.% NaCl eq.), high-density (similar to 0.8-0.9 g/cm(3)), CO2-rich aqueous fluids with up to similar to 50 mol% CO2(+CH4). The minimum entrapment conditions of carbonic-aqueous inclusions are calculated as 2-3 kbar and 350-360 degrees C, whereas aqueous inclusions in the granite and crosscutting quartz veins most likely correspond to lower-pressure conditions and fluid phase separation by decompression. The extreme level of fractionation and complex tetrad effects of the bulk-rock and ore minerals coupled with criteria indicating the magmatic-hydrothermal transition are in accord with regional seismic tomography and heat flow data. A much larger, unexposed parental granite system, from which the exposed Abu Dabbab rare-metal tip has fractionated, must be present at depth. The interaction between extreme fractionation and fluid-melt interaction at shallow crustal levels gave rise to economic-grade Ta-Nb-Sn +/- W mineralization in the granite body and associated quartz veins. (C) 2019 Elsevier B.V. All rights reserved.
英文关键词	Abu Dabbab rare-metal granite Egypt Elemental and isotopic data Extreme fractionation Magmatic-hydrothermal transition
类型	Article
语种	英语
国家	Egypt ; Germany ; Peoples R China ; Canada
收录类别	SCI-E
WOS记录号	WOS:000515201500031
WOS关键词	A-TYPE GRANITES ; COLUMBITE-TANTALITE MINERALS ; LA-ICP-MS ; FLUID INCLUSIONS ; TRACE-ELEMENTS ; BEARING LEUKOGRANITE ; CHEMICAL EVOLUTION ; TA MINERALIZATION ; GEOCHEMISTRY ; TIN
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
来源机构	南京大学
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/315146
作者单位	1.Benha Univ, Fac Sci, Dept Geol, Banha 13518, Egypt; 2.Univ Kiel, Inst Geosci, Ludewig Meyn Str 10, D-24118 Kiel, Germany; 3.Tech Univ Clausthal, Mineral Resources, D-38678 Clausthal Zellerfeld, Germany; 4.Aswan Univ, Fac Sci, Dept Geol, Aswan 81528, Egypt; 5.Nanjing Univ, Dept Earth Sci, Nanjing 210093, Peoples R China; 6.Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada; 7.Geosci Ctr, Dept Isotope Geol, D-337077 Gottingen, Germany
推荐引用方式 GB/T 7714	Zoheir, Basem,Lehmann, Bernd,Emam, Ashraf,et al. Extreme fractionation and magmatic-hydrothermal transition in the formation of the Abu Dabbab rare-metal granite, Eastern Desert, Egypt[J]. 南京大学,2020,352.
APA	Zoheir, Basem.,Lehmann, Bernd.,Emam, Ashraf.,Radwan, Abdelhady.,Zhang, Rongqing.,...&Nolte, Nicole.(2020).Extreme fractionation and magmatic-hydrothermal transition in the formation of the Abu Dabbab rare-metal granite, Eastern Desert, Egypt.LITHOS,352.
MLA	Zoheir, Basem,et al."Extreme fractionation and magmatic-hydrothermal transition in the formation of the Abu Dabbab rare-metal granite, Eastern Desert, Egypt".LITHOS 352(2020).