气候变化领域集成服务门户(CCPortal): A back-arc origin for the Neoarchean megacrystic anorthosite-bearing Bird River Sill and the associated greenstone belt; Bird River subprovince; Western Superior Province; Manitoba; Canada

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DOI	10.1007/s00531-019-01756-0
	A back-arc origin for the Neoarchean megacrystic anorthosite-bearing Bird River Sill and the associated greenstone belt; Bird River subprovince; Western Superior Province; Manitoba; Canada
	Sotiriou P.; Polat A.; Frei R.; Yang X.-M.; van Vessem J.
发表日期	2019
ISSN	14373254
起始页码	2177
结束页码	2207
卷号	108 期号:7
英文摘要	This study presents extensive new field, petrographic, and whole-rock major and trace element and Sm–Nd and Pb isotope data for the Neoarchean megacrystic anorthosite-bearing Bird River Sill, spatially associated Neoarchean supracrustal rocks of the Bird River greenstone belt, and the Mesoarchean Maskwa Lake TTG Batholith I, Manitoba, Canada. Field observations indicate that the 2743 Ma Bird River Sill was emplaced into the Northern Lamprey Falls Formation in an oceanic setting and subsequently intruded by the ca. 2725 Ma Maskwa Lake Batholith II. The Northern Lamprey Falls Formation is in fault contact with the overlying Peterson Creek Formation, which in turn is unconformably overlain by the Bird River Formation. The peridotites of the Bird River Sill were subjected to intense alteration and ductile shearing, resulting in the redistribution of many major and trace elements and resetting of their Sm–Nd and U–Th–Pb isotopic systems. The gabbro, leucogabbro, and anorthosite units of the sill largely retain their primary igneous textures and minerals, REE and HFSE compositions, and Sm–Nd and Pb isotope signatures. These geochemical and petrographic data indicate that these units of the Bird River Sill crystallised from a hydrous, Ca- and Al-rich tholeiitic magma that fractionated from a hydrous primitive arc tholeiitic parental magma. The major and trace element geochemistry and initial εNd values of the Bird River Sill (+ 0.53 to + 4.72) and the Northern Lamprey Falls Formation (+ 1.40 to + 2.66) of the Bird River greenstone belt crystallised from parental magma batches that were derived by partial melting of variably-depleted mantle sources. High-magnesian andesites from the Bird River Formation formed by partial melting of subducting oceanic crust and/or slab sediments and subsequent interaction with sub-arc mantle peridotite, whereas the Peterson Creek Formation dacites and Maskwa Lake TTG Batholith I tonalites formed by partial melting of juvenile lower arc crust. The major and trace element geochemistry of the Bird River Sill and greenstone belt and the Maskwa Lake TTG Batholith I, and geological relationships and lithological associations point to a transition from continental arc to continental back-arc magmatism along the southern active margin of the North Caribou terrane at ca. 2743 Ma, resulting in the formation of the Maskwa Lake microcontinent that occurred prior to subsequent continental arc magmatism along the southern margin of this microcontinent. Combined field observations and geochemical data indicate that the Bird River Sill and Bird River greenstone belt are a dismembered Archean subduction-related ophiolite that marks a suture zone between the Winnipeg River subprovince and the Maskwa Lake microcontinent. © 2019, Geologische Vereinigung e.V. (GV).
英文关键词	Anorthosite; Archean; Bird River greenstone belt; Bird River Sill; Bird River subprovince; Superior Province
语种	英语
来源期刊	International Journal of Earth Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/147790
作者单位	Department of Earth and Environmental Sciences, University of Windsor, Windsor, ON N9B 3P4, Canada; Geology Section, Department of Geosciences and Natural Resource Management, University of Copenhagen, København K, Copenhagen, 1350, Denmark; Manitoba Geological Survey, 360-1395 Ellice Avenue, Winnipeg, MB R3G 3P2, Canada
推荐引用方式 GB/T 7714	Sotiriou P.,Polat A.,Frei R.,et al. A back-arc origin for the Neoarchean megacrystic anorthosite-bearing Bird River Sill and the associated greenstone belt; Bird River subprovince; Western Superior Province; Manitoba; Canada[J],2019,108(7).
APA	Sotiriou P.,Polat A.,Frei R.,Yang X.-M.,&van Vessem J..(2019).A back-arc origin for the Neoarchean megacrystic anorthosite-bearing Bird River Sill and the associated greenstone belt; Bird River subprovince; Western Superior Province; Manitoba; Canada.International Journal of Earth Sciences,108(7).
MLA	Sotiriou P.,et al."A back-arc origin for the Neoarchean megacrystic anorthosite-bearing Bird River Sill and the associated greenstone belt; Bird River subprovince; Western Superior Province; Manitoba; Canada".International Journal of Earth Sciences 108.7(2019).