干旱区生态环境知识资源中心(Arid): Ar-40/Ar-39 and U-Pb SIMS zircon ages of Ediacaran dikes from the Arabian-Nubian Shield of south Jordan

Arid

DOI	10.1016/j.precamres.2020.105714
	Ar-40/Ar-39 and U-Pb SIMS zircon ages of Ediacaran dikes from the Arabian-Nubian Shield of south Jordan
	Ghanem, Hind; McAleer, Ryan J.; Jarrar, Ghaleb H.; Al Hseinat, Mu'ayyad; Whitehouse, Martin
通讯作者	Ghanem, H
来源期刊	PRECAMBRIAN RESEARCH
ISSN	0301-9268
EISSN	1872-7433
出版年	2020
卷号	343
英文摘要	A spectacular feature of the Arabian-Nubian Shield (ANS) is the abundance of well-exposed and extensive Neoproterozoic dike swarms of variable compositions. Most of these dikes are late to post-orogenic with respect to the East African Orogen (EAO) and are unmetamorphosed. We dated a composite dike with lathe margins and a rhyolite core (607 +/- 6 Ma, U-Pb), a biotite rhyolite dike (600 +/- 4 Ma, Ar-40/Ar-39 age of biotite), an andesite dike (594 +/- 3, Ar-40/Ar-39 age of amphibole) and a dolerite dike (similar to 579 Ma, Ar-40/Ar-39 whole rock total gas age). We propose that the first three dikes represent one generation that was emplaced at different episodes extending between 607 and 590 Ma. Time and composition equivalent dikes are common in the northern ANS. The dikes crosscut late collisional granitoids and geochemically display a subduction-related character as evidenced by a negative Nb-Ta anomaly. These dikes are absent in the alkali feldspar A-type Humrat Syenogranite dated at 586 +/- 5 Ma in Jordan and equivalent rocks in the northern ANS, which are crosscut only by the (similar to 579 Ma) dolerite dikes. The within-plate character of the dolerite dikes is supported by the absence of the Nb-Ta anomaly and high field strength element geochemistry. We propose that the dolerite dikes are a generation, distinct from the similar to 607-590 Ma dikes, that reflects a change in tectonic regime and represents the last magmatic activity of the Neoproterozoic in the northern ANS. The ages of the dikes dated in this study agree with the published age range of the transitional stage from late orogenic calc-alkaline to extensional alkaline tectono-magmatic setting for the ANS. We propose that the magmatic activity was terminated similar to 50 m.y. before the age of the Cambrian unconformity at similar to 530 Ma. Correlation with ages of dikes and magmatic rocks in the northern ANS favors this supposition. The dike geochemistry and geochronology are compatible with a tectonic model that involves mantle lithosphere delamination from below the northern ANS after a significant crust-mantle thickening caused by the EAO, followed by thermal relaxation, subsidence and gradual denudation until the age of the unconformity at similar to 530 Ma.
英文关键词	Ediacaran Dikes Arabian Nubian Shield Ar-40/Ar-39 geochronology U-Pb SIMS zircon Jordan
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000532835600006
WOS关键词	NORTH EASTERN DESERT ; NAJD FAULT SYSTEM ; A-TYPE GRANITES ; CRUSTAL EVOLUTION ; DYKE SWARMS ; TH-PB ; GEOCHEMICAL CONSTRAINTS ; CHEMICAL CLASSIFICATION ; SARAMUJ CONGLOMERATE ; METAMORPHIC COMPLEX
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
来源机构	United States Geological Survey
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/324450
作者单位	[Ghanem, Hind; Jarrar, Ghaleb H.; Al Hseinat, Mu'ayyad] Univ Jordan, Dept Geol, Queen Rania St, Amman 11942, Jordan; [McAleer, Ryan J.] US Geol Survey, 12201 Sunrise Valley Dr, Reston, VA 20192 USA; [Whitehouse, Martin] Swedish Museum Nat Hist, Box 50007, SE-10405 Stockholm, Sweden
推荐引用方式 GB/T 7714	Ghanem, Hind,McAleer, Ryan J.,Jarrar, Ghaleb H.,et al. Ar-40/Ar-39 and U-Pb SIMS zircon ages of Ediacaran dikes from the Arabian-Nubian Shield of south Jordan[J]. United States Geological Survey,2020,343.
APA	Ghanem, Hind,McAleer, Ryan J.,Jarrar, Ghaleb H.,Al Hseinat, Mu'ayyad,&Whitehouse, Martin.(2020).Ar-40/Ar-39 and U-Pb SIMS zircon ages of Ediacaran dikes from the Arabian-Nubian Shield of south Jordan.PRECAMBRIAN RESEARCH,343.
MLA	Ghanem, Hind,et al."Ar-40/Ar-39 and U-Pb SIMS zircon ages of Ediacaran dikes from the Arabian-Nubian Shield of south Jordan".PRECAMBRIAN RESEARCH 343(2020).