干旱区生态环境知识资源中心(Arid): Evolution of a Neoproterozoic island arc in the northern Arabian-Nubian Shield: Volcanic rocks and their plutonic equivalents in the Hamash area, south Eastern Desert, Egypt

Arid

DOI	10.1016/j.precamres.2021.106145
	Evolution of a Neoproterozoic island arc in the northern Arabian-Nubian Shield: Volcanic rocks and their plutonic equivalents in the Hamash area, south Eastern Desert, Egypt
	Gharib, Moustafa E.; Maurice, Ayman E.; Ahmed, Ahmed H.; Asimow, Paul D.; Bakhit, Bottros R.; Selim, Hussam A.
通讯作者	Maurice, AE (corresponding author), Helwan Univ, Fac Sci, Geol Dept, Cairo 11795, Egypt.
来源期刊	PRECAMBRIAN RESEARCH
ISSN	0301-9268
EISSN	1872-7433
出版年	2021
卷号	358
英文摘要	A suite of Neoproterozoic island arc volcanic and plutonic rocks are exposed in the Hamash area of the south Eastern Desert of Egypt. The volcanic assemblage includes metabasalt, a group of andesites with subordinate basalts (the Hamash Volcanics), and felsic volcanic porphyry. The plutonic rocks include a diorite-tonalite series, fine-grained granite, and granite porphyry. The volcanic rocks are generally sub-alkaline and feature a strong depletion in Nb and Ta. The metabasalt belongs to the low-K tholeiitic series and has nearly flat rare-earth element patterns. Its compositional characteristics indicate generation by partial melting of a depleted mantle source in an immature oceanic island arc setting. On the other hand, the basalt, andesite and felsic volcanic porphyry have low- to medium-K calc-alkaline affinity and are enriched in light rare-earth elements and large ion lithophile elements. Their parental magmas likely formed by fluid-assisted partial melting of a less depleted mantle source with major subduction input, in a mature island arc setting. The andesite cannot be derived from the basalt by fractional crystallization; their parental magmas likely represent different degrees of melting underneath crust of different thickness. Estimation of the arc crustal thickness during formation of these rocks yields similar to 5 km for the metabasalt, similar to 20 km for the Hamash basalt, and similar to 30 km for the Hamash andesite, consistent with a progression in maturity of the arc over time. The geochemical characteristics of the dioritetonalite series suggest that it represents an intrusive equivalent of the medium-K calc-alkaline Hamash andesite, and the fine-grained granite represents residual liquid after continued fractionation of the parental magma of the andesite and diorite-tonalite. We present thermodynamic fractionation models that constrain the conditions of fractionation for the andesite, diorite-tonalite, and fine-grained granite suite. The compositional similarity of the granite and rhyolite porphyries, especially their SiO2 and Al2O3 contents and Y/Nb ratios, indicate generation by partial melting of similar crustal sources, although greater assimilation of upper crust is evident in elevated Rb/Sr ratios and K2O and light rare-earth element concentrations in the granite porphyry. We conclude that the magmatic rocks of the Hamash area represent an arc crustal section that records the evolution of a Neoproterozoic oceanic island arc. The arc was later caught up in the assembly of the northern Arabian-Nubian Shield.
英文关键词	Neoproterozoic Arc evolution Magma generation Arabian-Nubian Shield Eastern Desert Egypt
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000652101500006
WOS关键词	CONTINENTAL-CRUST FORMATION ; ISUA GREENSTONE-BELT ; SILICIC MAGMAS ; ELEMENT TRANSPORT ; GEOCHEMICAL EVIDENCE ; SOUTHEASTERN DESERT ; MELTING EXPERIMENTS ; DOKHAN VOLCANICS ; WEST GREENLAND ; PETROGENESIS
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/2XILL650/351424
作者单位	[Gharib, Moustafa E.; Maurice, Ayman E.; Ahmed, Ahmed H.; Selim, Hussam A.] Helwan Univ, Fac Sci, Geol Dept, Cairo 11795, Egypt; [Ahmed, Ahmed H.] King Abdulaziz Univ, Fac Earth Sci, Jeddah, Saudi Arabia; [Asimow, Paul D.] CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA; [Bakhit, Bottros R.] Beni Suef Univ, Fac Sci, Geol Dept, Bani Suwayf 62517, Egypt
推荐引用方式 GB/T 7714	Gharib, Moustafa E.,Maurice, Ayman E.,Ahmed, Ahmed H.,et al. Evolution of a Neoproterozoic island arc in the northern Arabian-Nubian Shield: Volcanic rocks and their plutonic equivalents in the Hamash area, south Eastern Desert, Egypt[J],2021,358.
APA	Gharib, Moustafa E.,Maurice, Ayman E.,Ahmed, Ahmed H.,Asimow, Paul D.,Bakhit, Bottros R.,&Selim, Hussam A..(2021).Evolution of a Neoproterozoic island arc in the northern Arabian-Nubian Shield: Volcanic rocks and their plutonic equivalents in the Hamash area, south Eastern Desert, Egypt.PRECAMBRIAN RESEARCH,358.
MLA	Gharib, Moustafa E.,et al."Evolution of a Neoproterozoic island arc in the northern Arabian-Nubian Shield: Volcanic rocks and their plutonic equivalents in the Hamash area, south Eastern Desert, Egypt".PRECAMBRIAN RESEARCH 358(2021).