Gold metallogeny of Southern Mongolia

DOI: 10.47765/0869-5997-2025-10006

Abstract

Within the Southern Mongolia, the South Gobi gold ore belt stretching in the sublatitudinal direction for almost 1000 km is the most promising in terms of ore gold. Several gold ore regions are distinguished within its boundaries, the most significant of which are the Oyu Tolgoi, Kharmagtai, OlonOvoot, Dayangar, Manlai, and Tsagaan Suvarga ones. In the eastern segment of the belt, within the MandalOvoot terrane, the Olon-Ovoot ore region is distinguished with different-age hydrothermal-metasomatic gold ore mineralization of various types, represented by the Olon-Ovoot, Khurimt-Khuduk, Itgel, and UnegenDel ore deposits. The maximum potential for gold reserves in Southern Mongolia is related to gold-copper porphyry deposits comprised into the Oyu Tolgoi and Kharmagtai ore regions. In the Oyu Tolgoi ore region, the Oyu Tolgoi ore field is exclusively highly estimated. It comprises seven individual ore deposits that contain in total more than 42 million tons of copper and 1850 tons of gold with fairly high grades. The ore mineralization is genetically associated with quartz monzodiorites and alkaline basalts of the Late Devonian. To the east of the Oyu Tolgoi region, the Tsagaan Suvarga ore cluster is distinguished with the Tsagaan Suvarga molybdenum-copper porphyry type deposit and several ore occurrences. They are characterized by rather
low gold (0.08 g/t) and silver (2 g/t) grades. The gold-copper porphyry deposits of the Kharmagtai ore district located 160 km northeast of the Oyu Tolgoi deposit have a great potential for gold reserves. The main Au-Cu porphyry mineralization is concentrated in the Kharmagtai ore field and is associated with porphyry systems of the Kharmagtai igneous complex. Resources of the ore field are estimated at 1.1 billion tons of ore, 37 million tons of copper, and 1.3 thousand tons of gold. In general, the South Mongolian metallogenic province can be considered one of the world richest ones in
terms of ore gold reserves. The most significant in this region are the gold-copper porphyry deposits located in the Oyu Tolgoi and Kharmagtai ore regions.