Many massive sulfide deposits have been discovered in the Upper Paleozoic rift-related volcaniclastic sequence in South China, among which the Yushui copper deposit is the most important due to its high grade. The deposit has been variably attributed as SEDEX (sedimentary exhalative) or MVT (Mississippi valley type). The Yushui copper deposit in Guangdong (South China) contains stratiform bornite-chalcopyrite orebodies (102.1 kt Cu @ 3.5%, 186.6 kt Pb @ 4.29%, 117.6 kt Zn @ 2.91%, and 339 t Ag @ 112 g/t) developed along the contact between Upper Carboniferous dolostone and Lower Carboniferous pebbly quartz sandstone, which indicates a shallow marine deposition environment. The Yushui deposit comprises an upper massive sulfide orebody and a lower stockwork orebody with intense alteration. In this study, we newly identified Carboniferous tuffs and syn-volcanic faults in the footwall, and exhalites in the hanging-wall. Hematite from the Cu ores yielded a U-Pb age of 320 ± 15 Ma (MSWD = 2.1, n = 57), and hydrothermal dolomite yielded a Sm-Nd isochron age of 308.1 ± 4.6 Ma (n = 7; MSWD = 0.94), which constrains the timing of mineralization at Yushui. These ages are coeval with the Carboniferous host rocks. Combining the evidence from the geological features (syn-volcanic faults, volcanic rocks, exhalites) and hematite trace element compositions, we suggest that the Yushui is a shallow marine VMS (volcanogenic massive sulfide) deposit. The Sr-Nd isotope composition of hydrothermal dolomite (ε_Nd ~−12) indicates that the ore-forming materials were originated from the crustal basement. The Yushui copper deposit was likely formed during the Late Carboniferous continental back-arc extension in eastern South China. The regional extension may have caused enhanced heat flow, which promoted fluid convection in the basement rocks. In addition, we suggest that volcanic rocks and disseminated chalcopyrite-pyrite mineralization in the Lower Carboniferous quartz sandstone and exhalites are good indicators for regional VMS prospecting.

华南上古生界与裂谷相关的火山碎屑岩层序中发现了许多块状硫化物矿床，其中以玉水铜矿床品位高而最为重要。该矿床被不同地归为 SEDEX（沉积喷流型）或 MVT（密西西比河谷型）。广东（华南）玉水铜矿床含有层状斑铜矿-黄铜矿矿体（102.1 kt Cu @ 3.5%、186.6 kt Pb @ 4.29%、117.6 kt Zn @ 2.91% 和 339 t Ag @ 112 g/t），沿上石炭统白云岩与下石炭统卵石石英砂岩接触，表明其为浅海沉积环境。玉水矿床由上部块状硫化物矿体和下部蚀变强烈的网状矿体组成。在这项研究中，我们新发现了下盘中的石炭系凝灰岩和同火山断层，以及上盘中的喷出岩。铜矿石中的赤铁矿得出的 U-Pb 年龄为 320 ± 15 Ma（MSWD = 2.1，n = 57），热液白云石得出的 Sm-Nd 等时线年龄为 308.1 ± 4.6 Ma（n = 7；MSWD = 0.94） ，这限制了玉水的成矿时间。这些年龄与石炭纪主岩同时代。结合地质特征（同火山断层、火山岩、喷出岩）和赤铁矿微量元素组成等证据，认为玉水矿床为浅海相VMS（火山块状硫化物）矿床。热液白云石( ε _Nd ~−12)的Sr-Nd同位素组成表明成矿物质来源于地壳基底。玉水铜矿床很可能形成于华南东部晚石炭世大陆弧后伸展期间。区域延伸可能导致热流增强，从而促进了基岩中的流体对流。此外，我们认为下石炭统石英砂岩和火山岩中的火山岩和浸染状黄铜矿-黄铁矿矿化是区域VMS找矿的良好指标。