The emerald mineralization in the Habachtal (Austria) is geologically and tectonically complex, and previous investigators have identified fluid inclusion evidence for a hydrothermal/metamorphic origin for the emeralds. In this paper we report the discovery of emeralds with a distinctly different inclusion population including melt inclusions, which demonstrates that at least some and probably most of the emerald mineralization in the Habachtal occurred from an extremely fluid-rich pegmatite-like aluminosilicate melt under supercritical conditions, at high temperatures and moderate pressures (~700 °C, 5 kbar). This conclusion is based on the presence of very highly-ordered graphite, and extremely water-rich melt inclusions in emerald. The Lorentz distribution of MgCO 3 against the water concentration is a very robust proof for the supercritical state. We suggest that the purely metamorphic model, based on the extrapolation of fluid inclusion data to the regional metamorphic conditions (550 °C and 5 kbar) by some previous investigators are inconsistent with our finding of high-temperature indications (well-ordered graphite, high-temperature fluid inclusions and melt inclusions). This apparent conflict suggests a more complex situation and requires a re-investigation of the emerald genesis in the Habachtal deposit.

中文翻译：

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来自哈巴赫谷的祖母绿：新观察

Habachtal（奥地利）的祖母绿矿化在地质和构造上非常复杂，之前的研究人员已经确定了祖母绿的热液/变质成因的流体包裹体证据。在本文中，我们报告了具有明显不同包裹体群的祖母绿的发现，包括熔体包裹体，这表明 Habachtal 中至少部分和可能大部分的祖母绿矿化发生在超临界条件下极其富含流体的伟晶岩状铝硅酸盐熔体, 在高温和中等压力下 (~ 700 °C, 5 kbar)。这一结论是基于祖母绿中存在高度有序的石墨和极其富水的熔体包裹体。MgCO 3 相对于水浓度的洛伦兹分布是超临界状态的一个非常可靠的证据。我们认为，基于流体包裹体数据外推到区域变质条件（550 °C 和 5 kbar）的纯变质模型由一些先前的研究人员与我们发现的高温迹象（有序石墨，高-温度流体包裹体和熔体包裹体）。这种明显的冲突表明情况更为复杂，需要重新调查 Habachtal 矿床中祖母绿的成因。基于流体包裹体数据外推到区域变质条件（550℃和5kbar）之前一些研究者与我们发现的高温迹象（有序石墨、高温流体包裹体和熔体包裹体）不一致. 这种明显的冲突表明情况更为复杂，需要重新调查 Habachtal 矿床中祖母绿的成因。基于流体包裹体数据外推到区域变质条件（550℃和5kbar）之前一些研究者与我们发现的高温迹象（有序石墨、高温流体包裹体和熔体包裹体）不一致. 这种明显的冲突表明情况更为复杂，需要重新调查 Habachtal 矿床中祖母绿的成因。