干旱区生态环境知识资源中心(Arid): Suprasubduction-zone origin of the podiform chromitites of the Bir Tuluhah ophiolite, Saudi Arabia, during Neoproterozoic assembly of the Arabian Shield

Arid

DOI	10.1016/j.lithos.2020.105439
	Suprasubduction-zone origin of the podiform chromitites of the Bir Tuluhah ophiolite, Saudi Arabia, during Neoproterozoic assembly of the Arabian Shield
	Abuamarah, Bassam A.1; Asimow, Paul D.2; Azer, Mokhles K.3; Ghrefat, Habes 1
通讯作者	Abuamarah, Bassam A.
来源期刊	LITHOS
ISSN	0024-4937
EISSN	1872-6143
出版年	2020
卷号	360
英文摘要	The ultramafic section of a dismembered ophiolite is exposed at Bir Tuluhah, in the north-central part of the Arabian Shield. It is penetratively serpentinized and locally carbonate-altered to talc-carbonate and quartz-carbonate rocks (listvenite) along shear zones and fault planes. Despite the high degree of mineral replacement, preserved mesh and bastite textures and fresh relics of primary Cr-spinel and olivine show that the protoliths were mainly harzburgite with minor dunite, with sparse massive chromitite bodies of various forms and sizes. Olivine inclusions in the chromitite lenses have higher forsterite content and NiO concentrations than fresh olivine relics in the host harzburgites and clunites, due to subsolidus re-equilibration. Cr-spinels in the chromitites have higher Cr# (0.74-0.82) than those hosted in dunite (0.72-0.76) or harzburgite (0.55-0.66). The scarce Cr-spinel crystals in harzburgite that have Cr# < 0.6 are interpreted to represent the population least affected by melt-rock interaction. The chromitite bodies are interpreted to have formed just below the contact between the oceanic crust and mantle sections (i.e., the petrologic Moho). The primary olivine (high Fo and Ni content) and Cr-spinel core compositions (high Cr# and low TiO2 content) of the Bir Tuluhah serpentinized peridotite are typical of modern supra-subduction zone (SSZ) fore-arc peridotites and consistent with crystallization from boninitic magma. The multistage petrogenesis leading to the chromitite bodies begins with moderate to high degrees of melt extraction from the protoliths of the serpentinized harzburgites, followed by reaction with melt compositions that evolved from tholeiite to boninite and left dunite residues. The massive Cr-rich chromitites in the Bir Tuluhah ophiolite are most probably the residues of such interaction between depleted harzburgite and ascending melts; mixtures of the reacted melts formed boninites, which became saturated with chrome-rich spinel and crystallized chromite pods before ascending past the Moho. We offer a novel thermodynamic model of this mixing and reaction process that quantifies the yield of Cr-spinel. (C) 2020 Elsevier B.V. All rights reserved.
英文关键词	Arabian Shield Bir Tuluhah Cr-rich chromitite Fore-arc Melt-rock reaction Supra-subduction zone
类型	Article
语种	英语
国家	Saudi Arabia ; USA ; Egypt
开放获取类型	Green Accepted
收录类别	SCI-E
WOS记录号	WOS:000528205200019
WOS关键词	SOUTH EASTERN DESERT ; NUBIAN SHIELD ; SPINEL COMPOSITIONS ; MANTLE PERIDOTITES ; LUOBUSA OPHIOLITE ; CHROMIAN SPINEL ; GIANT CHROMITE ; ALASKAN-TYPE ; CR-SPINEL ; GEOCHEMISTRY
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
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/2XILL650/315149
作者单位	1.King Saud Univ, Dept Geol & Geophys, Riyadh 11451, Saudi Arabia; 2.CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA; 3.Natl Res Ctr, Geol Sci Dept, Cairo 12622, Egypt
推荐引用方式 GB/T 7714	Abuamarah, Bassam A.,Asimow, Paul D.,Azer, Mokhles K.,et al. Suprasubduction-zone origin of the podiform chromitites of the Bir Tuluhah ophiolite, Saudi Arabia, during Neoproterozoic assembly of the Arabian Shield[J]. King Saud University,2020,360.
APA	Abuamarah, Bassam A.,Asimow, Paul D.,Azer, Mokhles K.,&Ghrefat, Habes.(2020).Suprasubduction-zone origin of the podiform chromitites of the Bir Tuluhah ophiolite, Saudi Arabia, during Neoproterozoic assembly of the Arabian Shield.LITHOS,360.
MLA	Abuamarah, Bassam A.,et al."Suprasubduction-zone origin of the podiform chromitites of the Bir Tuluhah ophiolite, Saudi Arabia, during Neoproterozoic assembly of the Arabian Shield".LITHOS 360(2020).