Mineral Deposit Model of Cu–Fe–Au Skarn System in the Edongnan Region, Eastern China

Abstract

Cu and Fe skarns are the world's most abundant and largest skarn type deposits, especially in China, and Au‐rich skarn deposits have received much attention in the past two decades and yet there are few papers focused on schematic mineral deposit models of Cu–Fe–Au skarn systems. Three types of Au‐rich deposits are recognized in the Edongnan region, Middle–Lower Yangtze River metallogenic belt: ∼140 Ma Cu–Au and Au–Cu skarn deposits and distal Au–Tl deposits. 137–148 Ma Cu–Fe and 130–133 Ma Fe skarn deposits are recognized in the Edongnan region. The Cu–Fe skarn deposits have a greater contribution of mantle components than the Fe skarn deposits, and the hydrothermal fluids responsible for formation of the Fe skarn deposits involved a greater contribution from evaporitic sedimentary rocks compared to Cu–Fe skarn deposits. The carbonate‐hosted Au–Tl deposits in the Edongnan region are interpreted as distal products of Cu–Au skarn mineralization. A new schematic mineral deposit model of the Cu–Fe–Au skarn system is proposed to illustrate the relationship between the Cu–Fe–Au skarn mineralization, the evaporitic sedimentary rocks, and distal Au–Tl deposits. This model has important implications for the exploration for carbonate–hosted Au–Tl deposits in the more distal parts of Cu–Au skarn systems, and Fe skarn deposits with the occurrence of gypsum‐bearing host sedimentary rocks in the MLYRB, and possibly elsewhere.

Reconstruction of the Pacific plate: Constraints from ocean floor and eastern China

“…2,71,114 The LYRB is roughly linearly distributed (~30 km × 500 km), albeit with several kinks and formed within several million years (Figure 6). It consists mainly of skarn and porphyry Cu-Au, polymetallic deposits, 79,[115][116][117][118][119] and iron deposits, 92,118,[120][121][122][123][124][125][126][127][128] which belong to iron oxide copper gold (IOCG) deposits.…”

Origin of the dioritic porphyrite and its associated Matouniu skarn gold polymetallic deposits in the Eastern Hebei Province, North China: Evidence from geochronology, geochemistry, and C–O–S–Pb–Hf isotopes

“…Most skarn gold deposits in China are located in the collisional orogenic belts, intracontinental fault-controlled magmatic belts, and reactivated cratonic margins, and were formed by geodynamics that involved a transition from a compression to an extension regime (Chang et al, 2019;Chen et al, 2007;Meinert et al, 2005;Xie, Mao, et al, 2020;Zhao et al, 1999). Magmatic rocks related to the mineralization of skarn-type gold deposits in China were mainly formed during the late Yanshanian (Jurassic-Cretaceous), with ore bodies mainly distributed in or near the contact zone of intrusions and the rock surrounding them (Chang et al, 2019;Chen et al, 2007).…”