榴辉岩中传统地质温压计新解:来自PT视剖面图的证据

CORC > 北京大学 > 地球与空间科学学院

	榴辉岩中传统地质温压计新解:来自PT视剖面图的证据; A new interpretation of the conventional thermobarometry in eclogite: Evidence from the calculated PT pseudosections
	魏春景 ; 苏香丽 ; 娄玉行 ; 李艳娟
刊名	岩石学报
	2009
关键词	榴辉岩地质温压计 PT视剖面图 Eclogite Geothermobarometry PT pseudosection
英文摘要	石榴石-单斜辉石(GC)温度计和石榴石-单斜辉石-多硅白云母(GCP)压力计是确定榴辉岩形成温压条件的最常用方法,二者主要依据石榴石、绿辉石和多硅白云母中相组分之间的交换和转换变质反应。依据MORB成分计算的PT视剖面图表明,在不同榴辉岩矿物组合中,控制3个矿物相成分变化的相组分之间的变质反应不同。在低温含绿泥石、滑石和蓝闪石榴辉岩组合中,石榴石和绿辉石的镁含量主要受到含水矿物脱水反应的控制,并都随温度升高而升高,二者之间的铁镁交换反应并不起主要作用。因此,在自然界含有蓝闪石等含水矿物的低温榴辉岩中,由于绿辉石相对富镁而常常导致GC温度计结果偏低。在含有硬柱石的高压-超高压榴辉岩中,石榴石中的...; The garnet-clinopyroxene ( GC) thermometer and garnet-clinopyroxene-phengite(GCP) barometer are commonly used for determining the PT conditions of eclogite metamorphism. These thermobarometries are calibrated from the exchange and net transfer reactions among the phase components in garnet, clinopyroxene and phengite. The calculated PT pseudosections from a MORB composition indicate that in different eclogite assemblages there are different exchange and net transfer reactions among the phase components to control the compositions of the three minerals: In the chlorite-, talc- and glaucophane-bearing low-T eclogites, the Mg-contents in garnet and omphacite are dependent on the dehydrations of hydrous minerals, increasing as temperature rise, and the Fe-Mg exchange reaction between garnet and omphacite plays a trivial role. Thus, in the natural low-T eclogites which contain glaucophane and other hydrous minerals, omphacite is usually rich in Mg, which may result in the GC thermometer giving lower temperature results, In the lawsonite-bearing HP-UHP eclogites, the Ca-contents in garnet are dependent on the proportions of lawsonite, decreasing as pressure rise or temperature decrease. In this case, the net transfer reactions among garnet, omphacite and phengite may have a minor effect on the garnet compositions, an(] the GCP barometer may give lower pressure results due to garnet poor-in Ca. In the medium-T kyanite-bearing UP-UHP eclogites, the garnet, omphacite and phengite compositions are largely controlled by the Fe-Mg exchange reactions between garnet and omphacite, and the net transfer reactions in garnet- omphacite- phengite- kyanite- quartz / coesite. Thus, both GC thermometer and GCP barometer can give available PT results. In the lower-P hornblende-bearing eclogite, the Mg-contents in garnet and omphacite mainly reflect pressure changes, and commonly do not reflect temperature variations. The average PT mode (avPT) in Thermocalc could give available temperature results, and relatively lower pressures similar to those from the GCP barometer for the glaucophane-bearing low-T eclogites, but could not yield reasonable PT formation for the medium-T kyanite eclogites without the hydrous minerals such as glaucophane and epidote etc. Comparatively, the pseudosection thermobarometry can provide much more PT formation, and is the most optimal method for determining the metamorphic PT conditions.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000270044500004&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); 19; 09; 2078-2088; 25
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/50139]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	魏春景,苏香丽,娄玉行,等. 榴辉岩中传统地质温压计新解:来自PT视剖面图的证据, A new interpretation of the conventional thermobarometry in eclogite: Evidence from the calculated PT pseudosections[J]. 岩石学报,2009.
APA	魏春景,苏香丽,娄玉行,&李艳娟.(2009).榴辉岩中传统地质温压计新解:来自PT视剖面图的证据.岩石学报.
MLA	魏春景,et al."榴辉岩中传统地质温压计新解:来自PT视剖面图的证据".岩石学报 (2009).