Hydrothermal Albitite from the Myanmar Jadeite Deposit
详细信息
- 责任者：Wang Jing (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Shi Guanghai
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(4)
- 关键词：钠长石 ; albite ; 翡翠 ; jadeite ; 缅甸 ; Burma
- 页码：p.1450-1460
- 图表：illus., 3 tables, 54 refs.
- 分类号：0700
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
Albitites occur commonly in the jadeitite area. Jadeitite, a rock made up almost entirely of jadeitic pyroxene, forms under a relatively high-P/T condition in the subduction zones. Jadeitites have attracted remarkable attention of geologists and gemologists from all over the world and many localities of jadeitites have been well-documented. However, there has been little understanding about the albitites. Albitites in the Myanmar jadeite area, which are always associated with jadeitites, are perfect samples for understanding formation of the jadeitite and related events. Albitite is mainly composed of low-temperature albite, pyroxene minerals such as jadeite, omphacite and diopside and amphibole minerals such as richterite, winchite and magnesio-riebeckite, natrolite. Replacement of the jadeite by albite in the albitite along its cleavage and crack indicates that albite forms later than the jadeite. Albite record conditions of lower pressure than the jadeitite, and it was formed at temperature lower than 300℃, thus it is concluded that albite forms during uplift of the jadeitite through hydrothermal filling and precipiation. Diopside in the albitite consists of two types: one formed by replacement of jadeite which contains some components of diopside, the other is inferred to be the residual which was part of the replaced rocks like rodingite or pyroxenite belonging to the host serpentine melánge. The latter can be used as mineralogical evidence for confirmation of jadeitized pyroxenite and jadeitized rodingite. Existence of the abitite shows that Na-rich fluids are thorough and traversing.
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