Metallogenic age of the Khar Morit W-Sn deposit in Gebi Tianshan of Mongolia and geological significance of its comparison with ore-forming age of Beishan area in China

Abstract: SHRIMP U-Pb data of zircons from the strongly greisenized granite at the Khar Morit W-Sn ore deposit in Gobi Tianshan of South Mongolia shows that the emplacement age of granite intrusion is (214±3) Ma, which indicates that the W-Sn mineralization of the deposit took place during Triassic in Early Mesozoic. According to the comprehensive analysis of the data avialable, the authors hold that two episodes of W-Sn mineralization existed in Beishan area of China: one in Devonian and the other in Triassic. The metallogenic time of the Khar Morit W-Sn deposit in Mongolia’s Gobi Tianshan is coeval with that of the second W-Sn ore-forming event in Beishan, China. The spatial-temporal relationships between the tectonic evolution and the W-Sn mineralization suggest that the W-Sn ore deposits produced during the two metallogenic episodes all occurred in a collision to post-collision setting. The Devonian W-Sn ore deposits were related to the collisional event between the Dunhuang and Beishan blocks, which took place during Late Silurian-Early Devonian period, whereas the Triassic ones were likely related to the orogeny brought about by the final closure of the Paleo-Asian Ocean at about the end of Late Paleozoic.