| 大别山-苏鲁超高压变质带的矿物学和岩石学研究进展 |
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| 引用本文： | 叶凯.大别山-苏鲁超高压变质带的矿物学和岩石学研究进展[J].矿物岩石地球化学通报,2001,20(3):141-148. |
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| 作者姓名： | 叶凯 |
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| 作者单位： | 中国科学院地质与地球物理研究所 |
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| 基金项目： | 国家自然科学基金项目 ( 40 0 2 5 2 10 )，科技部国家基础研究发展规划项目 (G19990 75 5 0 1) |
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| 摘 要： | 本文总结了近年来大别山 苏鲁超高压变质带的矿物学和岩石学进展。针对大别山 苏鲁超高压变质带中的区域片麻岩围岩是否经历超高压变质的问题 ,研究者在常规岩石学和矿物学手段不能奏效的情况下 ,引入显微喇曼光谱测试 ,最终在各种类片麻岩的锆石中发现柯石英、硬玉和雯石等高压和超高压矿物包裹体 ,证明大别山 苏鲁超高压变质带中的大多数岩石曾与榴辉岩一起被俯冲到地幔深度 ,后又一起回返到地表。在喇曼光谱的测试过程中 ,发现锆石中的柯石英包裹体有 0～ 2 3 0 0MPa不等的现时晶内超压 ,并证明这种晶内超压是超高压变质岩回返过程中 ,柯石英向石英转化而导致的体积膨胀造成的。研究者在产于青岛仰口榴辉岩的石榴子石中发现大量单斜辉石、金红石和磷灰石出熔 ,精细的晶体化学和岩石学研究证明出熔前的石榴子石形成于大于 70 0 0MPa的压力条件 ,说明苏鲁地区的部分陆壳岩石可能曾被俯冲到大于 2 0 0km深的地幔。岩石学研究发现产于桃行地区的榴辉岩在角闪岩相区域退变质之前 ,在 4 0～ 5 0km的浅部地幔深度发育有一期高压麻粒岩相 过渡榴辉岩相变质。进一步研究发现这期变质是由于峰期的多硅白云母在回返到 4 0～5 0km深的浅部地幔时脱水熔融导致的
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| 关 键 词： | 超高压变质带 大别山苏鲁地区 矿物学 岩石学 |
| 文章编号： | 1007-2802(2001)03-0141-08 |
| 修稿时间： | 2001年6月21日 |
Study Progress of Mineralogy and Petrology in Dabieshan-Sulu Ultrahigh-Pressure (UHP) Metamorphic Terrane |
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| YE,Kai.Study Progress of Mineralogy and Petrology in Dabieshan-Sulu Ultrahigh-Pressure (UHP) Metamorphic Terrane[J].Bulletin of Mineralogy Petrology and Geochemistry,2001,20(3):141-148. |
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| Authors: | YE Kai |
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| Abstract: | This paper reviewed recent mineralogical and petrological progresses of the Dabieshan Sulu ultrahigh pressure (UHP) metamorphic terrane. The areal extent and tectonic process of the UHP metamorphism in the Dabieshan Sulu UHP terrane is a long term debate, the key problem is whether the country gneisses of coesite eclogite suffered UHP metamorphism. Traditional petrological methods revealed only amphibolite facies metamorphism in the country gneisses. Recently, Raman microspectroscopy was frequently used to identify minute inclusions in zircon, which was regard as good container of minerals formed in previous evolution. Coesite, jadeite and aragonite were commonly identified in zircons extracted from all types of the country gneisses in the Dabieshan Sulu UHP terrane, indicating that the terrane had ever been subducted to depth greater than 80 km as a coherent slab. Micro Raman analysis also revealed 0-2.3 GPa present day overpressures in the coesite zircon system. Detailed studies show that the overpressure was resulted from volume enlargement induced by coesite quartz transition in zircon. Petrological observation revealed abundant clinopyroxene, rutile and apatite exsolutions in garnet of eclogite from Yangkou. Combination of studies of high pressure experiments and crystal chemistry proved that the parent homogeneous garnet was formed at pressures greater than 7 GPa, indicating that the host eclogite had ever been subducted to depths greater than 200 km. Detailed petrological work indicated that the coesite eclogite from Taohang region suffered a transitional eclogite to high pressure granulite facies overprint predated the pervasive amphibolite facies retrogression, further study proved that the transitional eclogite to high pressure granulite facies overprint is triggered by dehydration melting of peak phengite during the earlier exhumation to 40-50 km depths. |
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| Keywords: | ultrahigh pressure (UHP) metamorphic terrane Dabieshan Sulu area mineralogy petrology |
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