Geology and Mineralization Characteristics of Khamkeut Saen Oudom Gold Deposit, Bolikhamxai, Lao PDR
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Abstract
The Khamkeut Saen Oudom (KSO) gold deposit is located at Bolikhamxai province, central Lao PDR. It lies within the Truong Son Fold Belt where there are several significant mineral deposits particularly gold and copper. At KSO deposit, the mineralization occurs as quartz - carbonate veins, minor stockworks and breccias. Major veins are trending almost E-W where it forms as single ore zone in the west and splays to three narrow veins at the eastern part of area. Several ore lenses are present along this E-W structure (e.g., Houay Keh, Nam Pan-east, Nam Pan-west). The gold mineralized veins/stockworks/breccias are mainly hosted by meta-sedimentary rocks (e.g., meta-sandstone, meta-siltstone and phyllite) of inferred Ordovician to Silurian age. At least three stages of mineralization have been identified namely; Stage 1, microcrystalline quartz - arsenopyrite - pyrite; Stage 2, quartz ± calcite - sulfides (arsenopyrite - pyrite - sphalerite - chalcopyrite - galena-pyrrhotite) - gold and Stage 3, quartz - chlorite - calcite. Alteration at KSO deposit is less pervasive and extensive and mainly characterized by quartz - calcite - sericite - chlorite and chlorite - sericite - calcite assemblages, and the both are developed in ore lenses. The quartz - calcite - sericite - chlorite alteration is featured by predominant presence of cryptocrystalline quartz, calcite, and sericite. EPMA analysis reveals that gold fineness of Houay Keh ore lens range 827 to 866 (represented by native gold) and Nam Pan ore lens range from 637 to 715 (represented by electrum).
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Copyright © 2008 Department of Geology, Faculty of Science, Chulalongkorn University. Parts of an article can be photocopied or reproduced without prior written permission from the author(s), but due acknowledgments should be stated or cited accordingly.
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