Petrological and Sr-Nd-Os isotopic constraints on the origin of the   Fanshan ultrapotassic complex from the North China Craton

doi:10.1016/j.lithos.2012.05.017

CORC > 北京大学 > 地球与空间科学学院

	Petrological and Sr-Nd-Os isotopic constraints on the origin of the Fanshan ultrapotassic complex from the North China Craton
	Niu Xiaolu ; Chen Bin ; Liu Ankun ; Suzuki, K. ; Ma Xu
刊名	lithos
	2012
关键词	Ultrapotassic alkaline rocks Petrology Os-Nd-Sr isotopes Mantle metasomatism Fanshan complex North China Craton LITHOSPHERIC MANTLE BENEATH IONIZATION MASS-SPECTROMETRY ULTRAMAFITE-SYENITE COMPLEX LOWER CONTINENTAL-CRUST ASIAN OROGENIC BELT SINO-KOREAN CRATON U-PB HEBEI PROVINCE OSMIUM ISOTOPE TRACE-ELEMENT
DOI	10.1016/j.lithos.2012.05.017
英文摘要	The Fanshan ultramafic-syenitic complex is located on the northern margin of North China Craton, with zircon U-Pb ages of 220 Ma. It is a concentrically zoned complex, with syenite in the core, surrounded by ultramafic rocks (clinopyroxenite, glimmerite) and garnet-clinopyroxene syenite, respectively, towards the rim. Diopside, biotite, orthoclase, melanite, magnetite and apatite are the major minerals, with subordinate sphene and calcite. Mineralogy, petrology and geochemical studies point to the formation of the complex through fractional crystallization and accumulation from a SiO2-undersaturated ultrapotassic alkaline-peralkaline parent magma that is characterized by high CaO, Fe2O3, K2O and fluid compositions (P2O5, CO2, H2O, F), and by high temperature and high oxygen fugacity. Rocks from the complex are highly enriched in light rare earth elements (LREE) and large ion lithophile elements (LILE; e.g., Rb, Ba, Sr), depleted in high field strength elements (HFSE; e.g., Nb, Ta, Ti), and show relatively homogeneous Sr-Nd isotopic compositions with initial Sr-87/Sr-86 = 0.70513-0.70597 and epsilon(Nd)(t)= -5.8 to -5.3. The data suggest that the Fanshan complex originated from a phlogopite-clinopyroxenite-rich lithosphere mantle source that had previously been metasomatized by melts from carbonated oceanic crust above a subduction zone. Highly radiogenic Os isotope compositions (initial Os-187/Os-188 = 0.299-2.449) suggest that the parent magma to the Fanshan complex has been contaminated by Precambrian mafic crustal rocks during magma emplacement in crustal levels. The occurrence of the Fanshan complex, together with many other ultramafic/alkaline plutons of similar ages, on the northern margin of the North China Craton suggests that the northern margin of the craton entered into a large-scale extensional regime in late Triassic after the final amalgamation between Mongolian microcontinent and the craton. (C) 2012 Elsevier BM. All rights reserved.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000309153000012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; Geochemistry & Geophysics; Mineralogy; SCI(E); 15; ARTICLE; ,SI; 146-158; 149
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/155690]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Niu Xiaolu,Chen Bin,Liu Ankun,et al. Petrological and Sr-Nd-Os isotopic constraints on the origin of the Fanshan ultrapotassic complex from the North China Craton[J]. lithos,2012.
APA	Niu Xiaolu,Chen Bin,Liu Ankun,Suzuki, K.,&Ma Xu.(2012).Petrological and Sr-Nd-Os isotopic constraints on the origin of the Fanshan ultrapotassic complex from the North China Craton.lithos.
MLA	Niu Xiaolu,et al."Petrological and Sr-Nd-Os isotopic constraints on the origin of the Fanshan ultrapotassic complex from the North China Craton".lithos (2012).