A New Model for Formation of Lacustrine Primary Dolomite by Subaqueous Hydrothermal Venting

Almost 230 years after it was first described, formation of the mineral dolomite remains enigmatic. Dolomitic rocks are abundant throughout geological record, and most thought to form by replacement limestone. Recent work has identified substantial volumes high-temperature primary deposited in Cretaceous lacustrine rift basins Northern China. Here we provide missing conceptual understanding fundamental processes that may have formed such dolomitic sediments combining an analysis physics chemistry sub-lacustrine hydrothermal systems with new data on mineralogy geochemistry dolomites. This novel mechanism accounts for systematic changes characteristics sequence intimately link evolution convection within fault damage zone venting brine-rich mixtures lake basin, provides a model be tested against high-enthalpy settings as rifting basins.