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	On the cratonization of the Arabian-Nubian Shield: Constraints from gneissic granitoids in south Eastern Desert, Egypt
	Khudeir Ali A; Paquette Jean Louis; Nicholson Kirsten; Johansson Ake; Rooney Tyroneo; Hamid Sadiq; El-Fadly Mohamed A; Corcoran Loretta; Malone Shawn J; El-Rus Mohamed Ali Abu
来源期刊	地学前缘
ISSN	1674-9871
出版年	2021
卷号	12 期号:4 页码:1674-9871
英文摘要	The Shaitian granite complex(SGC)spans more than 80 Ma of crustal growth in the Arabian-Nubian Shield in southeast Egypt. It is a voluminous composite intrusion(60 km~2)comprising a host tonalite massif intruded by subordinate dyke-like masses of trondhjemite, granodiorite and monzogranite. The host tonalite, in turn, encloses several, fine-grained amphibolite enclaves. U-Pb zircon dating indicates a wide range of crystallization ages within the SGC(800 18Ma for tonalites;754 3.9 Ma for trondhjemite;738 3.8 Ma for granodiorite;and 7173.2 Ma for monzogranite), suggesting crystallization of independent magma pulses. The high positive epsilonNdi(+6-+8)indicate that the melting sources were dominated by juvenile material without any significant input from older crust. Application of zircon saturation geothermometry indicates increasing temperatures during the generation of melts from 74531 °C for tonalite to 81025 °C for trondhjemite;84010 °C for granodiorite;and 86810 °C for monzogranite. The pressure of partial melting is loosely constrained to be below the stability of residual garnet(<10 kbar)as inferred fromthe almost flatHREE pattern((Gd/Lu)_N=0.9-1.1), but>3 kbar for the stability of residual amphibole as inferred from the significantly lower Nb_N and Ta_N compared with LREE_N and the sub-chondrite Nb/Ta ratios exhibited by the granitic phases. The inverse relation between the generation temperatures and the ages estimates of the granitoid lithologies argue against a significant role of fractional crystallization. The major and trace element contents indicate the emplacement of the SGC within a subduction zone setting. It lacks distinctive features for melt derived from a subducted slab(e.g. high Sr/Y and high(La/Yb)_N ratios), and the relatively low MgO and Ni contents in all granite phases within the SGC suggest melting within the lower crust of an island arc overlying a mantlewedge. Comparisonwith melts produced during melting experiments indicates an amphibolite of basaltic composition is the best candidate as source for the tonalite, trondhjemite and granodiorite magmas whereas the monzogranite magma is most consistent with fusion of a tonalite protolith. Given the overlapping Sm-Nd isotope ratios as well as several trace element ratios between monzogranite and tonalite samples, it is reasonable to suggest that the renewed basaltic underplating may have caused partialmelting of tonalite and the emplacement ofmonzogranite melt within the SGC. The emplacement of potassic granite(monzogranite)melts subsequent to the emplacement of Na-rich granites(tonalitetrondhjemite-granodiorite)most likely suggests major crustal thickening prior arc collision and amalgamation into the over thickened proto-crust of the Arabian-Nubian shield. Eventually, after complete consolidation, the whole SGC was subjected to regional deformation, most probably during accretion to the Saharan Metacraton(arc-continent collisions)in the late Cryogenian-Ediacaran times(650-542 Ma).
英文关键词	Arabian-Nubian Shield(ANS) Cratonization Fractional crystallization Partial melting Subduction zones Tonalite-Trondhjemite-granodiorite(TTG)
类型	Article
语种	英语
国家	中国
收录类别	CSCD
WOS类目	Geology
CSCD记录号	CSCD:7013958
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/364978
作者单位	Khudeir Ali A, Geology Department, Faculty of Science, Assiut University, 71516, Egypt.; Hamid Sadiq, Geology Department, Faculty of Science, Assiut University, 71516, Egypt.; El-Fadly Mohamed A, Geology Department, Faculty of Science, Assiut University, 71516, Egypt.; El-Rus Mohamed Ali Abu, Geology Department, Faculty of Science, Assiut University, 71516, Egypt.; Paquette Jean Louis, Universite Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, Clermont-Ferrand, F-63000, France.; Nicholson Kirsten, Ball-State University, Department of Environment, Geology and Natural Resources, Muncie, 47306, USA.; Malone Shawn J, Ball-State University, Department of Environment, Geology and Natural Resources, Muncie, 47306, USA.; Johansson Ake, Department of Geosciences, Swedish Museum of Natural History, Stockholm, SE-104 05, Sweden.; Rooney Tyroneo, Department of Earth and Environmental Sciences, Michigan-State University, East Lansing, 48824, USA.; Corcoran Loretta, Notre Dame University, Department ...
推荐引用方式 GB/T 7714	Khudeir Ali A,Paquette Jean Louis,Nicholson Kirsten,et al. On the cratonization of the Arabian-Nubian Shield: Constraints from gneissic granitoids in south Eastern Desert, Egypt[J],2021,12(4):1674-9871.
APA	Khudeir Ali A.,Paquette Jean Louis.,Nicholson Kirsten.,Johansson Ake.,Rooney Tyroneo.,...&El-Rus Mohamed Ali Abu.(2021).On the cratonization of the Arabian-Nubian Shield: Constraints from gneissic granitoids in south Eastern Desert, Egypt.地学前缘,12(4),1674-9871.
MLA	Khudeir Ali A,et al."On the cratonization of the Arabian-Nubian Shield: Constraints from gneissic granitoids in south Eastern Desert, Egypt".地学前缘 12.4(2021):1674-9871.