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地球科学进展  2004, Vol. 19 Issue (5): 722-731    DOI: 10.11867/j.issn.1001-8166.2004.05.0722
研究论文     
青藏东缘六合—香多镁铁质深源包体的平衡 P-T条件及其指示意义
魏启荣1,2;王江海2
中国地质大学材料科学与化学工程学院,湖北 武汉 430074;中国科学院广州地球化学研究所,广东 广州 510640
EQUILIBRIUM P-T CONDITIONS OF MAFIC DEEP-DERIVED ENCLAVES AND ITS SIGNIFICANCE IN LIUHE-XIANGDUO AREA OF EASTERN TIBET
WEI Qi-rong1,2, WANG Jiang-hai2
1.College of Materials Science & Chemical Engineering, China University of Geosciences,Wuhan 430074, China; 2. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
 全文: PDF(243 KB)  
摘要:

依据青藏东缘六合-香多镁铁质深源包体中石榴石、辉石、角闪石和斜长石的矿物电子探针成分,采用GrtCpx温度计(T EG79、T P85、T K88、和 T R2000)、GrtHbl温度计(T GP84和 T RV2000)和HblPl温度计(T BH90)以及角闪石Al压力计(P AlinHb l)估算了包体的平衡温压条件。结果表明,石榴透辉岩、石榴斜长角闪岩、石榴角闪岩、斜长角闪岩和角闪石岩包体的平衡温压分别是770~920℃和 0.83~1.50GPa(相当于27~50km深)、730~950℃和 0.85~1.04GPa(相当于28~34km深)、 720~900℃和 0.74~1.32GPa(相当于24~44km深)、512~753℃和 0.71~0.98GPa(相当于23~32km深)以及 0.60~0.84GPa(相当于20~28km深)。前 3类包体主要来自下地壳,平衡温压较高(720~950℃、0.74~1.50GPa);后 2类包体主要来自中地壳,平衡温压较低(510~735℃、0.60~0.98GPa)。包体的平衡温压条件还暗示了高钾岩浆起源的最小深度在50km以上。

关键词: 六合-香多青藏东缘镁铁质深源包体平衡温压    
Abstract:

Based on electron microprobe analyses of garnets, pyroxenes, amphiboles and plagioclases from mafic deep-derived enclaves in Liuhe-Xiangduo area, eastern Tibet, calculated equilibrium temperatures of the enclaves by Grt-Cpx geothermometers (TEG79, TP85,TK88, and TR2000), Grt-Hblgeothermometers (TGP84and TRV2000), and Hbl-Plgeothermometers (TBH90), and equilibrium pressures by aluminum-in-amphibole geobarometrys (PAl-in-Hbl). The results showed that equilibrium temperatureand pressureconditions of garnet diopsidite, garnet amphibolite, garnet hornblendite, amphiboliteand hornblenditewere 770~920 ℃ and 0.83~1.50 GPa (equivalent to27~50 km depth), 730~950 ℃ and 0.85~1.04 GPa (28~34 km), 720~900 ℃ and 0.74~1.32 GPa (24~44 km), 512~753 ℃ and 0.71~0.98 GPa (23~32 km), and 0.60~0.84 GPa (20~28 km). The P-T conditions in the enclaves revealed the former three types of enclaves came from low-crust with higher P-T (720~950 ℃ and 0.74~1.50 GPa), and the latter two derived from middle-crust with lower P-T ( 510~735 ℃ and 0.60~0.98 GPa). The P-Tconditionof enclaves still indicated the source depth of the high-K magma is 50km at least. 

Key words: Eastern Tibet    Liuhe-Xiangduo    Mafic deep-derived enclave    Equilibrium temperature and pressureconditions.
收稿日期: 2003-06-05 出版日期: 2004-10-01
:  P58  
基金资助:

国家重点基础研究发展规划项目“大陆碰撞过程中壳幔物质能量交换及冈底斯带成矿背景评估”(编号:G1998040807);中国博士后科学基金项目“三江中段扬子与冈瓦纳陆块间地球化学边界的研究”资助

通讯作者: 魏启荣(1964-),男,湖北蒲圻人,副教授,主要从事火山岩岩石学、地球化学和无机材料研究.     E-mail: E-mail:weiqr1030@cug.edu.cn
作者简介: 魏启荣(1964-),男,湖北蒲圻人,副教授,主要从事火山岩岩石学、地球化学和无机材料研究.E-mail:weiqr1030@cug.edu.cn
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引用本文:

魏启荣;王江海. 青藏东缘六合—香多镁铁质深源包体的平衡 P-T条件及其指示意义[J]. 地球科学进展, 2004, 19(5): 722-731.

WEI Qi-rong, WANG Jiang-hai. EQUILIBRIUM P-T CONDITIONS OF MAFIC DEEP-DERIVED ENCLAVES AND ITS SIGNIFICANCE IN LIUHE-XIANGDUO AREA OF EASTERN TIBET. Advances in Earth Science, 2004, 19(5): 722-731.

链接本文:

http://www.adearth.ac.cn/CN/10.11867/j.issn.1001-8166.2004.05.0722        http://www.adearth.ac.cn/CN/Y2004/V19/I5/722

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