雪宝顶绿柱石的谱学研究

Mineral Spectroscopic Studies of Beryls from Xuebaoding, Sichuan

本文对雪宝顶绿柱石的晶体化学、矿物谱学、热释光和流体包裹体特征等进行了分析讨论。结果表明 ,雪宝顶绿柱石化学成分具有富碱、富水 ,过渡金属离子以Fe3+、Fe2 +为主的特点。碱金属离子、水和Fe2 +存在于绿柱石结构隧道中 ,隧道水分为Ⅰ型和Ⅱ型两类 ,Ⅰ型水可以进一步区分为Ⅰ1和Ⅰ2 两亚类 ,Fe2 +主要与隧道水结合形成水合离子 [Fe2 +(H2 O) ]。Fe3+主要占位于绿柱石AlO6八面体中的Al3+位 ,是导致绿柱石呈浅绿色的主要杂质离子。绿柱石的热释光强度和峰温可作为其标型特征之一。成矿溶液属于气成高温热水溶液 ,且富含大量碳酸或碳酸气。

Studies of beryls from Xuebaoding by means of crystal chemistry, optical analysis, EPR and infrared spectroscopy indicate that beryls have high alkali ions and water content. Ferric ions(Fe 3+ ) occupy octaheral sites, whereas ferrous ions(Fe 2+ ), alkali ions and water molecules exist in the channel sites. There are two types of water molecules in the channel structure, namely Ⅰ type and Ⅱ type. Ⅰ type water molecules can probably be further divided into two subtypes(Ⅰ 1 and Ⅰ 2). The combination of ferrous ions(Fe 2+ ) with water molecules in the channel structure results in hydrated ferrous ions[Fe 2+ (H 2O)]. The green colour of beryls is caused by ferric ions(Fe 3+ ). The thermoluminescence strengths and peak temperatures of beryls can be regarded as the typomorphic characteristics. The deposit is genetically of hypothermal type. Ore_forming solutions have abundant acidulous water and mephitic air.