Controls of temperature and mineral growth rate on Mg incorporation in aragonite

The incorporation of Mg in aragonite was experimentally investigated as a function mineral growth rate at 5, 15 and 25 °C using the constant addition technique. Aragonite found to be major parameter affecting partitioning coefficient (i.e. DMg=(MgCa)solid(MgCa)fluid) between fluid, whereas effect temperature is smaller but measurable. At similar surface normalized rates, DMg values decrease increases from 5 °C. magnitude for all experiments this study where varied range 10-8.6 ≤ rp 10-7.1 (mol/m2/s). combined on can described by linear equation: Log = 0.583(±0.020) − 0.026(±0.001) T + 0.863(±0.153); R2 0.97. degrees Celsius. increase decreasing temperatures conducted rates consistent with fluid supersaturation respect aragonite. Thus, it inferred that increased higher associated greater presence defect sites growing surface, other incompatible ions carbonate minerals. Overall, relationship content degree saturation phase suggests or Mg/Ca ratio natural aragonites used proxy formation CaCO3