Paleoenvironment of Mesoproterozoic Gaoyuzhuang and Wumishan Formations, North China: New Insights from Geochemistry and Carbon and Oxygen Isotopes of Dolostones

The Mesoproterozoic Gaoyuzhuang and Wumishan Formations are major geothermal reservoirs in the Hebei Province, North China. Compared to exploration of resources heat-controlling structures, carbon oxygen isotopic records two formations limited. Here, we present integrated field, petrological, geochemical, carbon, data carbonate rocks from Formations. Formation is characterized by higher CaO MgO contents lower SiO2 than Formation, indicating that source likely contains less terrigenous clastic materials. have low total rare earth element contents, similar marine rocks. They show different Eu Ce anomalies, Al/(Al + Fe Mn) Fe/Ti ratios, (Co Ni Cu) contents. generally compositions, whereas middle-upper δ18O values samples These suggest experienced transgressive–regressive cycles their sedimentary environments varied were unstable periods. was affected hydrothermal fluids, composed normal seawater deposits. Integrated evidence reveals both deposited rift caused breakup Columbia/Nuna supercontinent.