Paleo-Tethys tectonic-magmatic evolution and gold-copper metallogenesis in Luang Prabang (Laos)-Loei (Thailand) metallogenic belt

The Luang Prabang (Laos)-Loei (Thailand) metallogenic belt is located on the northwestern margin of the Indochina Block and is one of the important gold-copper metallogenic belts in the Indo-China Peninsula. It has experienced the Paleo-Tethys tectonic-magmatic evolution during the Late Paleozoic-Mesozoic, leading to complex metallogenic activities and forming porphyry-skarn Cu-Au, epithermal Au-Ag, and hydrothermal vein-type gold deposits, respectively. However, the genetic type of hydrothermal vein-type gold deposits is still controversial. There is no summary as well on relationship between the three types of gold-copper deposits and the regional tectonic evolution up to now.In this paper, by summarizing the previous research data of typical deposits, and combining with new evidence from study on source and evolution of ore-forming fluids, we conclude the hydrothermal vein-type gold deposits in the belt as orogenic gold deposits. Based on regional tectonic-magmatic-metallogenic research, the temporal and spatial distribution, as well as metallogenic characteristics of three types of typical gold-copper deposit including porphyry-skarn Cu-Au deposits, epithermal Au-Ag deposits and orogenic gold deposits in the belt was summarized. We also establish a regional metallogenic model related to the subduction-closure of the Paleo-Tethys Ocean plate and subsequent continental-continental collision process, consisting of porphyry-skarn Cu-Au in Late Permian-Early Triassic subduction period, epithermal Au-Ag inEarly-Middle Triassic closure period, and orogenic Au in Late Triassic collision period.