Ag‐rich Tetrahedrite in the El Zancudo Deposit, Colombia: Occurrence, Chemical Compositions and Genetic Temperatures
Ag‐rich Tetrahedrite in the El Zancudo Deposit, Colombia: Occurrence, Chemical Compositions and Genetic Temperatures
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DOI：
10.1111/j.1751-3928.2010.00133.x
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发表时间：
2010-09
期刊：
影响因子：
1.4
通讯作者：
A. Gallego Hernández;M. Akasaka
中科院分区：
文献类型：
--
作者：
A. Gallego Hernández;M. Akasaka
富银四面体-Freiberite固溶体的化学组成对哥伦比亚安蒂奥基亚El Zancudo存款9个矿脉17个样品的石英和碳酸盐岩中的流体包裹体（富银四面体）和均一温度进行了研究，以揭示富银四面体中银的来源，推导出它们的结晶温度，并研究富银四面体的化学组成与它们的结晶温度之间的关系。矿石由毒砂、黄铁矿、闪锌矿、富银四面体辉石、方铅矿、方铅矿、硫锑铅矿、硅镁矾、黄绿柱石、脆硫锑铅矿、硫银矿、水银矿、黄铜矿和银金矿组成。富银四面体石约占矿石总量的10体积%，是该存款中最常见和分布最广的磺酸盐之一。富含Ag的四面体富含Ag（1.13至31.02重量%）和Sb（22.93至29.82重量%），并且缺乏As（0.06至2.43重量%），这与所报道的富含Ag的四面体中Ag和As的不相容性一致。Zn/（Zn + Fe）-、Ag/（Ag + Cu）-和Sb/（Sb + As + Bi）-原子比在矿脉之间表现出一些变化。具有较高Ag/（Ag + Cu）比率的富Ag四面体与黄英石共存，而具有较低比率的富Ag四面体与该硫盐不相关。富Ag四面体元素+闪锌矿和富Ag四面体元素+水硼镁石+方铅矿的组合中的富Ag四面体元素分别在核和边缘之间没有Zn ParticipFe和Cu ParticipAg变化，否定了冷却过程中固态反应的可能性。因此，富银四面体被认为是主相。石英和碳酸盐中原生流体包裹体的均一化温度与富银四面体共存，确定矿化温度为134至263°C。利用Sack的热化学数据库，根据与银银矿、银银矿和黄铜矿等银矿物伴生的富银四面体的Zn/（Zn + Fe）和Ag/（Ag + Cu）比值，估算出富银黝铜矿的独立结晶温度在170 ° C至1250 °C之间。因此，这两个结果非常一致。
Chemical compositions of tetrahedrite—Ag‐rich tetrahedrite—freibergite solid solutions (Ag‐rich tetrahedritess) and homogenization temperatures of fluid inclusions in quartz and carbonates of seventeen samples from nine veins in the El Zancudo deposit, Antioquia, Colombia, were investigated to reveal the origin of silver in Ag‐rich tetrahedritess, to derive their crystallization temperatures and to examine the relationship between chemical compositions of Ag‐rich tetrahedritess and their crystallization temperatures. The ores consist of arsenopyrite, pyrite, sphalerite, Ag‐rich tetrahedritess, galena, boulangerite, andorite, owyheeite, diaphorite, jamesonite, miargyrite, bournonite, chalcopyrite, and electrum. Ag‐rich tetrahedritess forms about 10 volume % of the total ores and is one of the most common and widely distributed sulfosalts in this deposit. Ag‐rich tetrahedritess is rich in Ag (1.13 to 31.02 wt%) and Sb (22.93 to 29.82 wt%), and poor in As (0.06 to 2.43 wt%), consistent with the reported incompatibilities of Ag and As in Ag‐rich tetrahedritess. The Zn/(Zn + Fe)‐, Ag/(Ag + Cu)‐ and Sb/(Sb + As + Bi)‐atomic ratios exhibit some variations among the veins. Ag‐rich tetrahedritess with higher Ag/(Ag + Cu) ratios coexist with diaphorite, whereas those with lower ratios are not associated with this sulfosalt. Ag‐rich tetrahedritess in the assemblages of Ag‐rich tetrahedritess+ sphalerite and of Ag‐rich tetrahedritess+ bournonite + galena shows no Zn ↔ Fe and Cu ↔ Ag variations between core and rim, respectively, negating the possibility of solid state reaction during cooling. Ag‐rich tetrahedritess is thus regarded as primary phase. Homogenization temperatures of primary fluid inclusions in quartz and carbonates co‐existing with Ag‐rich tetrahedritess define the mineralization temperatures of 134 to 263°C. Independent crystallization temperatures of Ag‐rich tetrahedrite estimated based on Zn/(Zn + Fe) and Ag/(Ag + Cu) ratios of the Ag‐rich tetrahedritess associated with silver minerals such as miargyrite, andorite and diaphorite using Sack's thermochemical database lie in a range between 170 and ∼250°C. Both results are thus in good agreement.