Composition of arsenopyrite from topaz greisen veins in southeastern Missouri
Composition of arsenopyrite from topaz greisen veins in southeastern Missouri
复制标题
密苏里州东南部黄玉灰岩脉中毒砂的成分
DOI：
--
复制
发表时间：
1982
期刊：
影响因子：
--
通讯作者：
C. Gasparrini
中科院分区：
文献类型：
--
作者：
G. R. Lowell;C. Gasparrini
毒砂产于密苏里州东南部银矿区未变质的前寒武纪花岗岩和流纹岩中的云英岩-硫化物脉中，云英岩化和硫化物矿化似乎是一个连续的沉积序列，记录了近地表矿脉环境中温度的下降。纹理标准意味着毒砂和黄铁矿之间存在平衡，这对结晶在云英岩和热液阶段之间的中间共生位置。对Einstein矿脉和Gabriel矿脉中的15个毒砂晶体进行了38次电子探针点样分析，未能揭示As/S的化学分带。所分析的毒砂的成分范围为32。9比31 0原子% As。Gabriel矿脉的毒砂结晶温度范围为485°C（±15°）至455°C（±15°）。相比之下，爱因斯坦矿脉中的毒砂的结晶温度范围较低，但较宽，为440°C（±15°）至368°C（±15°）。
Arsenopyrite occurs in greisen-sulfide veins hosted by unmetamorphosed Precambrian granite and rhyolite in the Silver Mine district of southeastern Missouri, Greisenization and sulfide mineralization appear to have been a continuous depositional sequence which recorded falling temperature in a near-surface vein environment. Textural criteria imply that equilibrium existed between arsenopyrite and pyrite and that this pair crystallized in an intermediate paragenetic position between the greisen and hydrothermal stages. Thirty-eight electron microprobe spot analyses of 15 arsenopyrite crystals from the Einstein and Gabriel veins failed to disclose chemical zoning of As/S. The compositional range of the analyzed arsenopyrites is 32. 9 to 31. 0 atomic % As. A range of arsenopyrite crystallization temperature from 485°C (±15°) to 455°C (±15°) is indicated for the Gabriel vein. In contrast, arsenopyrites from the Einstein vein record a lower and broader crystallization range of 440°C (±15°) to 368°C (±15°).