河北矾山杂岩体中单斜辉石的研究

CORC > 北京大学 > 地球与空间科学学院

	河北矾山杂岩体中单斜辉石的研究; Clinopyroxenes from the Fanshan pluton, Hebei
	牛晓露 ; 陈斌 ; 马旭
刊名	岩石学报
	2009
关键词	单斜辉石岩装演化过钾质碱性岩矾山杂岩体河北 Clinopyroxene Magma evolution Ultrapotassic alkaline rocks Fanshan pluton Hebei
英文摘要	河北矾山杂岩体属于二氧化硅不饱和的超钾质碱性-过碱性岩浆系列,由单斜辉石岩、辉石正长岩和碱长正长岩等不同类型岩石组成。各类型岩石主要组成矿物为单斜辉石、黑云母、石榴石和正长石。本文利用电子探针对单斜辉石进行了详细研究,发现所有单斜辉石属于高钙透辉石,随着岩浆的演化,主要表现为Fe~(2+)对Mg~(2+)的替代关系,结晶趋势为透辉石→钙铁辉石,这揭示矾山杂岩体岩浆体系的特点是高温、中等大小的氧逸度、贫硅、富碱(尤其是钾)。辉石中的Al~Ⅳ含量取决于岩浆的硅饱和度,硅越不饱和,Al~Ⅳ含量越高;Al~Ⅵ含量则与体系中的Al含量呈正相关关系。由Al对Si的替代引起的电荷不平衡主要由八面体位置的Fe...; The Fanshan complex from northern Hebei is an ultrapotassic alkaline-peralkaline pluton (silica-undersaturated), including clinopyroxenites, pyroxene-bearing syenites and alkali feldspar syenite. All the rocks mainly consist of clinopyroxenes, biotites, garnets and orthoclases. The clinopyroxenes have been studied in detail using microprobe in this paper. All of them are diopside belonging to Ca-rich clinopyroxene. Crystallization trend from diopside to hedenbergite, related to the replacement of Mg(2+) by Fe(2+) during magma evolution, is recognized from these clinopyroxexes. The features of clinopyroxenes above reflect that the magma system of the Fanshan pluton is characterized by high temperature, moderate oxygen fugacity, silica-undersaturated and high alkalis (especially potassium). The Al(IV) contents in clinopyroxene from the Fanshan pluton depend on SiO(2) concentrations in magma system; Al(IV) contents increase with decreasing SiO(2). Al(VI) contents are mainly controlled by At concentrations in magma system. The excess of the negative charge caused by the Si-Al substitution is mainly compensated by the entrance of Fe(3+) in the octahedral position, then by minor Ti(4+) and much lesser Al(3+). The Ti contents of clinopyroxenes are positively related to the temperature of the magma system; also, Na contents show positive relationship with the contents of Ti and Fe(3+) of clinopyroxenes. The evolution trends of the At and Ti contents from core to rim with decreasing Mg(#) are different in individual clinopyroxene grains from rocks of different types, and this is because the clinopyroxenes crystallized at different stages of magma evolution. That is, different clinopyroxene grains experienced different magma evolution history. The appearance of Ca-rich clinopyroxenes and the development of zoned clinopyroxenes in alkaline rocks are all caused by the characters of impoverished silica and enriched potassium of magma system. Clinopyroxene compositions are controlled not only by the P-T conditions when it crystallizes, but also the total magma compositions and its variations.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000265945400010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; SCI(E); 中文核心期刊要目总览(PKU); 中国科技核心期刊(ISTIC); 中国科学引文数据库(CSCD); 6; 02; 359-373; 25
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/49231]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	牛晓露,陈斌,马旭. 河北矾山杂岩体中单斜辉石的研究, Clinopyroxenes from the Fanshan pluton, Hebei[J]. 岩石学报,2009.
APA	牛晓露,陈斌,&马旭.(2009).河北矾山杂岩体中单斜辉石的研究.岩石学报.
MLA	牛晓露,et al."河北矾山杂岩体中单斜辉石的研究".岩石学报 (2009).