Timing of the Early Paleozoic Yangtze and Cathysian Convergence： Constraint from U-Pb Geochronology of Hydrothermal Zircons from Mafic Mylonite within the Shoucheng-Piaoli Ductile Shear Zone, Northern Guangxi

Objective The northern Guangxi region is in the southwestern part of the Southern China continent,which is located at the junction of the southwest section of the Early Paleozoic Yangtze block and Cathaysian block.A series of NNE-trending ductile shear zones are developed in this region,and these ductile shear zones are mostly previously suggested boundary faults of the Early Paleozoic Yangtze block and Cathaysian block,such as the Shoucheng–Piaoli ductile shear zone in Northern Guangxi （Meng Yuanku et al., 2016; Zhang Xuefeng et al., 2015）.

Metallogenesis and Geodynamic Setting of the Early Paleozoic Orogenic Gold Deposits in the North Altyn

The North Altyn has underwent a complex tectonic history in the Early Paleozoic and formed a number of orogenic gold deposits controlled by ductile to brittle shear zones adjacent to the southern side of the Northern Altyn Tagh fault e.g. the Dapinggou, Beiketan and Xiangyun. The Dapinggou gold deposit, a typical orogenic gold deposit in North Altyn, is predominantly hosted in the Precambrian carbonate and Cambrian volcano- sedimentary rocks which were strongly deformed and were subjected to low-grade metamorphism. The ore bodies occurred in K-feldspar quartz veins and hydrothermally altered mylonite within the ductile shear belt. Hydrothermal alteration including silicification, pyritization.