Petrology and geochemical characters of metalimestone from Ban Maepong Limestone Mine, Doi Saket District, Chiang Mai Province, Northern Thailand

Abstract

Limestone is economically the most abundant mineral resource in Chiang Mai province, and it has already been excavated for industrial purposes within Chiang Mai and nearby provinces for decades. Geologically, Ban Maepong limestone mine consists of sedimentary rocks, metamorphic rocks, and igneous rocks. According to the geological map, the study area is located within two rock units, such as the Permian rock unit and the Permian-Triassic volcanic rock unit. Moreover, the mountainous area in the east of the study area is located in a Triassic granitic rock unit. The metalimestones that were collected from the limestone mine are divided into two types. The first type is the calcic slate, which metamorphosed from an argillaceous limestone. The second type is metalimestone, which metamorphosed from pure limestone. The result of mineral chemistry revealed that calcite is the sole carbonate rock-forming mineral in both types. Therefore, the protolith of metalimestone from Ban Maepong limestone mine is sedimentary rock. This study can suggest that the metamorphism of the metalimestone in Ban Maepong limestone mine was affected by Permian-Triassic volcanic rock due to the volcanic eruption.