Mineralogy, Fluid Inclusion, and Stable Isotope Studies of the Chengchao Deposit, Hubei Province, Eastern China: Implications for the Formation of High-Grade Fe Skarn Deposits

摘要

The Chengchao Fe skarn deposit (280 Mt @ 45% Fe; nearly half of the total Fe reserve has an ore grade higher than 53 wt %) is the largest high-grade magnetite skarn deposit in the Middle-Lower Yangtze River metallogenic belt. The magnetite orebodies and skarns occur mainly along the contact zones between granitic (129 ± 2 Ma) rocks and diorite (133 ± 1 Ma) and Triassic strata. The paragenesis of the Chengchao deposit includes the following five stages: Na-K alteration stage (albite + K-feldspar), prograde skarn stage (garnet + pyroxene), retrograde skarn stage (magnetite + phlogopite + amphibole), sulfate-sulfide stage (anhydrite + pyrite ± garnet ± magnetite), and carbonate stage (calcite).