Source Characteristics of the Carboniferous Ortokarnash Manganese Deposit in the Western Kunlun Mountains

The specific source of ancient sedimentary manganese (Mn) deposits is commonly complex. Here we use systematic major and trace element data with strontium (Sr) neodymium (Nd) isotopic analyses the Ortokarnash Mn(II) carbonate ores associated rocks from Upper Carboniferous Kalaatehe Formation (ca. 320 Ma) in order to constrain Mn source. This formation consists three members: first member a volcanic breccia limestone, second sandy third black marlstone interlayers. Petrographic observations combination low Al2O3 (<3.0 wt%) Hf (<0.40 ppm) contents lack correlations between 87Sr/86Sr ratios as well εNd(t) values demonstrate negligible influence terrigenous detrital contamination on both Sr Nd compositions ores. isotopes are most likely affected by post-depositional alteration, while remain unaltered. initial result mixture chemical components (i.e., seawater) Al-rich (e.g., volcanoclastic material), effects negligible. In addition, these non-mineralized wall remained unchanged during processes. relatively Th/Sc positive suggest that aluminosilicate fraction calcarenite limestone was mainly derived weathering depleted mafic source, representing riverine input into seawater. Given characterized negative values, seafloor-vented hydrothermal fluids interaction underlying old continental crust contribute carbonates.