Formation of the Miaoan Au-Polymetallic Deposit in the Northern Taihang Mountain, North China Craton: Ore Geology, Geochronological and Geochemical Perspectives

Several gold ore-concentrated areas have been recognized in the destruction zone of the North China Craton (NCC). However, the deposits in the western part of the destruction zone have received less attention. Miaoan, a typical Au-polymetallic deposit in the northern Taihang Mountain, provides a good sample for deepening our understanding of the genesis of gold deposits in the western destruction zone. In this study, detailed ore geology, pyrite Rb-Sr age, trace element and S-C-O isotopes of Au-bearing ores were conducted to constrain the source of ore-forming materials and their tectonic setting. The pyrites obtain an Rb-Sr isochron age of 129.5 +/- 2.5 Ma, consistent with those of magmatic rocks in this deposit, suggesting their genetic relationship. The delta S-34 values ranging from -5.5 parts per thousand to 1.6 parts per thousand and the high Co/Ni and Y/Ho ratios of pyrites indicate the mantle-crust mixing characteristics of ore-forming fluids. The delta C-13 (-6.3 parts per thousand to -2.0 parts per thousand) and delta O-18 (9.3 parts per thousand to 17.6 parts per thousand) values of Au-bearing ores and calcites suggest mixing characteristics as well. Geochronologically, the Miaoan Au-polymetallic deposit was formed during the destruction of the NCC. We propose that the Miaoan Au-polymetallic deposit is a decratonic gold deposit and that its ore-forming materials have a mixed source of mantle and crust.

Automated summary

By studying the pyrite Rb-Sr age, trace elements, and S-C-O isotopes, the source of ore-forming materials and tectonic setting of the Miaoan Au-polymetallic deposit in the destruction zone of the North China Craton have been identified. Geochemical analysis suggests that the Miaoan Au-polymetallic deposit is a decratonic gold deposit with ore-forming materials sourced from both mantle and crust.