Mineralogy of pockets of the Malkhan tourmaline deposit (Transbaikalia): feldspars of the Sosedka vein
- 作者：V.Ye. Zagorsky ; victzag@igc.irk.ru
- 关键词：pegmatite ; microcline ; orthoclase ; adularia ; plagioclase ; structural ordering
- 刊名：Russian Geology and Geophysics
- 出版年：2012
- 期刊代码：10_10687971
- 类别：ear
- 出版时间：June, 2012
- 卷：53
- 期：6
- 页码：522-534
- 文件大小：584 K
摘要
A detailed study was given to the composition and structure of alkali feldspars from the pockets of the Sosedka pegmatite vein, a large source of gems within the Malkhan tourmaline deposit. The vein is of concentric-zonal structure. Three types of pockets were recognized by mineral composition: A鈥攓uartz-lepidolite-Mn-Li-Al-tourmaline (卤 pollucite, hambergite, borocookeite, boromuscovite, danburite, light pink beryl); B鈥攓uartz-adularia-axinite (卤 laumontite); and C鈥攓uartz and laumontite (卤 B-containing cookeite). Each type of pockets contains feldspars of specific composition and structure. This evidences that pockets formed in strongly different conditions, though some pockets of different types are localized as close as 0.5-2 m from each other within a zone. The reported data disagree with the common model implying the formation of zonal pegmatite bodies as a result of crystallization differentiation within the vein.