ACICULAR SPHALERITE ENRICHED IN Ag, Sb, AND Cu EMBEDDED WITHIN COLOR-BANDED SPHALERITE FROM THE KOKANEE RANGE, BRITISH COLUMBIA, CANADA
ACICULAR SPHALERITE ENRICHED IN Ag, Sb, AND Cu EMBEDDED WITHIN COLOR-BANDED SPHALERITE FROM THE KOKANEE RANGE, BRITISH COLUMBIA, CANADA
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DOI：
10.2113/gscanmin.38.6.1387
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发表时间：
2000-12
影响因子：
0.9
通讯作者：
G. Beaudoin
中科院分区：
文献类型：
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作者：
G. Beaudoin
来自不列颠哥伦比亚省科卡尼山脉的闪锌矿显示出从浅棕色到深棕色的色带。闪锌矿形成块状层，其暗色基底富含Fe和Cu。层具有尖锐的边界，可以是平面的或起伏的。闪锌矿层的基底通常含有垂直于层边界取向的闪锌矿针状晶体。针状闪锌矿富集Sb、Ag、Cu，在结构上替代Zn。地层的底部通常以黄铜矿、方铅矿、硫银矿和Freiberelite的复杂包裹体链为标志，这些包裹体模仿色带。层的厚度显示对数正态分布归因于一个随机过程，它被解释为依赖于在一个层的沉淀之前引入裂缝内的热液流体的量。针状闪锌矿可能是从富含Cu、Fe、Ag和Sb的溶液中形成的快速沉淀的纤锌矿转化而来的，这一推断得到了亚铁闪锌矿层底部硫化物和硫盐链的支持。针状纤锌矿的沉淀将耗尽溶液中的Cu、Ag、Sb，针状晶体嵌入富Zn闪锌矿中。在这些条件下，闪锌矿的色带受当地条件的控制，这阻止了其用于从一个矿脉到另一个矿脉的对比（闪锌矿地层学）。
Sphalerite from the Kokanee Range, British Columbia, displays color banding ranging from light to dark brown. Sphalerite forms massive layers with a dark base enriched in Fe and Cu. Layers have sharp boundaries that can be planar or undulating. The base of the sphalerite layers commonly contains acicular crystals of sphalerite oriented perpendicular to the layer boundary. Acicular sphalerite is enriched in Sb, Ag and Cu, which substitute for Zn in the structure. The base of the layers is commonly marked by chains of complex inclusions of chalcopyrite, galena, pyrargyrite and freibergite, which mimic color banding. The layer thickness displays a lognormal distribution ascribed to a random process; it is interpreted to be dependent on the amount of hydrothermal fluid introduced within a fracture prior to precipitation of a layer. The acicular sphalerite probably inverted from rapidly precipitated wurtzite formed from a solution enriched in Cu, Fe, Ag and Sb, an inference that is supported by chains of sulfides and sulfosalts at the base of ferroan sphalerite layers. The precipitation of acicular wurtzite would have depleted the solution in Cu, Ag, Sb, the acicular crystals becoming embedded in Zn-rich sphalerite. Under those conditions, the color banding of sphalerite is controlled by local conditions, which prevents its use for correlation (sphalerite stratigraphy) from one vein to the other.