Geological characteristics and prospecting target of the Pali Mountain iron deposit in SaiSongwen County , Vientiane Province, Laos

Abstract：Based on mineral resources survey of the Pali Mountain in SaiSongwen County, Vientiane Province of Laos, this paper deals with geological settings, geological characteristics, geophysical characteristics, ore genesis and prospecting perspective of the Pali Mountain iron deposit. Studies show that Variscan period was an important metallogenic epoch for rich iron deposits in Chuankuang-Changshan structure belt of Laos. The Pali Mountain iron deposit lies at the contact zone between granodiorite and Middle-Upper Devonian limestone in the Chuankuang-Changshan structure belt of Laos. The well-developed skarn bands corresponding to ten iron mineralized bodies are exposed in the mining district. The ore bodies all lie in garnet skarns formed by contact between granodiorite and limestone. The variations of the modes of occurrence of ore bodies are controlled by the skarns. The deposit was formed in magmatic epoch and ore bodies are mainly in lenticular, layered and stratoid forms in marble. Controlled strictly by fractured zones, the ore bodies lie in carbonate rock and calcareous sandstone and limestone of Middle-Upper Devonian period and the NW-, NE- and EW-trending fracture zones in strata. The ore deposit is a mesothermal skarn type iron deposit. The potential resource quantity of the Pali Mountain iron deposit is huge and the favorable places in search for the same type of iron deposits is in the depth and the periphery of the ore deposit. The host rocks are mainly skarn and skarnized limestone and calcareous sandstone of the Middle-Upper Devonian period. Ore minerals are mainly magnetite, hematite and subordinately limonite, chalcopyrite and pyrite. Vein minerals are mainly quartz, calcite, diopside，tremolite，garnet，chlorite, and epidote. This paper sums up the carbonate strata, the intrusion of granodiorite and the multiple activities of the Chuankuang-Changshan structure belt in Laos. The NW-, NE- EW-trending faults are the factors that jointly control the formation of the skarn-type iron deposit. Based on geological features, ore-controlling factors, this paper deals with prospecting criteria and targets in search for iron deposits in this region. The discovery of the Pali Mountain iron deposit has provided new train of thought and new data in search for this type of iron deposits in the Chuankuang-Changshan structure belt of Laos.