Déodat Gratet de Dolomieu made the first report of the presence of the mineral, rocks and mountains that bear his name in 1791 in the ‘Journal de Physique’. Dolomite is a relatively ‘stable’ carbonate mineral that doesn’t react easily with weak acid and classically contains equal amounts of Mg and Ca in the mineral lattice. The origins of early dolomite creation has remained a mystery for over 200 years. To complicate the mystery of its origins, the mass of dolomite as a sedimentary rock declines through the past 60 million years of time. This is in stark contrast to the mass-age distributions of other sedimentary rocks with time. Their masses all increase as the rocks get younger due to weathering and preservation effects on the Earth’s surface. The reduction of dolomite precipitation has also had a profound effect on the Mg/Ca of seawater over the last 60 million years. Over this time interval the Mg/Ca of seawater has increased from less than 2 to over 5 today… directly as a result of the reduction of dolomite precipitation in neritic (shallow water) environments. If you would like to hear about our discovery and the solution of to the long standing ‘Dolomite problem’, please come to the talk!