Petrogenesis of the similar to 500 Ma Fushui mafic intrusion and Early Paleozoic tectonic evolution of the Northern Qinling Belt, Central China

TitlePetrogenesis of the similar to 500 Ma Fushui mafic intrusion and Early Paleozoic tectonic evolution of the Northern Qinling Belt, Central China
Publication TypeJournal Article
Year of Publication2017
AuthorsShi Y., Pei X.L, Castillo P.R, Liu X.J, Ding H.H, Guo Z.C
JournalJournal of Asian Earth Sciences
Volume141
Pagination74-96
Date Published2017/06
Type of ArticleArticle
ISBN Number1367-9120
Accession NumberWOS:000404708500006
KeywordsEarly Paleozoic arc setting; geological; guanzizhen ophiolite; hf isotopes; high-field-strength; Metasomatized mantle source; Northern Qinling Belt; oceanic basalts; orogenic belt; Shangdan; significance; suture zone; tongbai orogen; trace-element; u-pb ages; volcanic-rocks
Abstract

The Fushui mafic intrusion in the Qinling orogenic belt (QOB) is composed of meta-gabbro, meta-gabbrodiorite, diorite, and syenite. Most of these rocks are metamorphosed under the upper greenschist facies to lower amphibolite facies metamorphism. Zircon separates from eight samples have LA-ICP-MS U-Pb ages of 497-501 Ma which are taken to be the emplacement age of magmas that formed the Fushui intrusion. Most of the zircon grains exhibit negative epsilon(HF) values, correspond to T-DMS model ages of late Paleoproterozoic-early Mesoproterozoic or Neoproterozoic and suggest that the mafic rocks were most probably derived from mafic melts produced by partial melting of a previously metasomatized litho spheric mantle. The intrusion is not extensively contaminated by crustal materials and most chemical compositions of rocks are not modified during the greenschist to amphibolite-facies metamorhism. Rocks from the intrusion have primitive mantle-normalized trace element patterns with significant enrichment in light-REE and large ion lithophile elements (LILE) and depletion in high field-strength elements (HFSE). On the basis of the trace element contents, the Fushui intrusion was derived from parental magmas generated by <10% partial melting of both phlogopite-lherzolite and garnet-lherzolite mantle sources. These sources are best interpreted to be in a subduction-related arc environment and have been modified by fluids released from a subducting slab. The formation of the Fushui intrusion was related to the subduction of the Paleotethyan Shangdan oceanic lithosphere at similar to 500 Ma. (C) 2016 Elsevier Ltd. All rights reserved.

DOI10.1016/j.jseaes.2016.09.003
Short TitleJ. Asian Earth Sci.
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