| 大别-苏鲁超高压变质带柯石英榴辉岩成因的实验研究——以辉长岩→榴辉岩固相转换为例 | |
| 马拥军 | |
| 2001 | |
| Degree Grantor | 中国科学院地球化学研究所 |
| Place of Conferral | 中国科学院地球化学研究所 |
| Degree Name | 博士 |
| Degree Discipline | 应用地球化学 |
| Keyword | 高温高压实验 榴辉岩 形成深度 |
| Abstract | 本文通过辉长岩在高温、高压下的进变质作用过程的模拟，实现了辉长岩向榴辉岩的转变。在800，2.5Gpa以下，辉长岩生成了石榴石+辉石+长石±尖晶石的矿物组合，在800，2.5Gpa以上，辉长岩则生成石榴+辉石石英的榴辉岩组合。辉长岩向榴辉岩转变过程中存在一个过渡带，过渡带主要的特征是：随压力升高，石榴石逐渐增加，而斜长石逐渐减少。生成的石榴石中，镁铝榴石分子含量随压力的增大而增加，其成因分类属于地幔成因；生成的单斜辉石主要为富镁普通辉石，辉石中硬玉的含量较低。将实验结果与大别山榴辉岩形成条件相比，可以证实：1.大别山榴辉岩形成的温、压条件是在700-900 ℃，2.5Gpa以上；2.大别山柯石英榴辉岩的形成深度至少在80km以上。 |
| Other Abstract | The mineral assemblages of gabbro composition have been studied experimentally in the pressure range from 10kbar to 30kbar at temperatures above 800 ℃ and below the gabbro solidus. At low pressures, less than 25kbar, at 800 ℃ the mineral assemblages are characterized by the association of garnet + clinopyroxene + plagioclase ± spinel, but above 25kbar at 800 ℃ the major phase are garnet, clinopyroxene and quartz and the mineral assemblages match those of eclogites. At intermediate pressures the mineral assemblages are characterized by co-existence of garnet, clinopyroxene, plagioclase and spinel. The transition interval between the gabboic and eclogitic assemblages is a broad one characterized by gradual increase in garnet and in the pyrope content of the garnet, and decrease in plagioclase. The clinopyroxenes are mainly magnesium-rich augite. By comparison of the experimental data with astimates of the P, T conditions of eclogite in Dabie Mountains, it is argued that the formation of coesite-bearing eclogite in Dabie Mountains are about 700-900 ℃, more than 2.5Gpa; was the product of subduction of continental crust to a depth greater than 80km. |
| Pages | 40 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.gyig.ac.cn/handle/352002/3576 |
| Collection | 研究生_研究生_学位论文 |
| Recommended Citation GB/T 7714 | 马拥军. 大别-苏鲁超高压变质带柯石英榴辉岩成因的实验研究——以辉长岩→榴辉岩固相转换为例[D]. 中国科学院地球化学研究所. 中国科学院地球化学研究所,2001. |
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| LW006629.pdf（3699KB） | 暂不开放 | -- | Application Full Text | |||
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