硬玉成矿理论综述

翡翠作为一种稀缺的宝石资源,近年来价格一路飙升,对翡翠成矿理论的研究也逐渐升温。本文简述了作为宝石级翡翠的主要产地--缅甸的硬玉矿床地质概况,综述了硬玉的四类成矿理论,包括岩浆成因、变质成因、双交代成因和交代成因,认为硬玉由硅酸盐熔体在高温高压条件下直接结晶而成的观点比较科学合理。该岩浆成因理论根据硬玉的结构、包裹体、矿物组合、以及形成时的温压条件,推断出硬玉岩是岩浆在结晶压力低限为p>1.5GPa,温度变化范围在650～800℃之间的温压条件下形成的。本文对熔体来源问题进行了探讨,认为硅酸盐熔体可能与变质深熔的成岩成矿作用有关。

A discussion on jadeite formation mechanism

As a rare gemstone resource, jadeite has seen a rapid rise in price in recent years, resulting in warming study on jadeite formation mechanism. This paper summarized geological features of the jadeite deposits in Burma, the major production area of gemstone-grade jadeite, introduced four theories on jadeite formation such as magmatic origin, meta- morphic origin, double-metasomatic origin and metasomatic origin, and thought it more scientifically reasonable that jadeite had been directly crystallized from silicate melt under high-T and high-P conditions. Based on its texture, inclu- sion, mineral assemblage and T-P conditions at formation, jadeitite was thought to have been formed from magma by crystallization at the lower pressure limit of P〉I.5GPa and temperature range of 650 to 800℃. This paper discussed the source of the melt and argued that the silicate melt might have been related to diagenesis and metallogenesis of metamorphic anatexis.