Frank T. Manheim J. M. Gieskes P. C. Mangelsdorf Jr. 1970 <p>Calculations show that gravitational settling of ions in an isothermal sediment column could produce increases of equilibrium concentrations in pore waters ranging from 1 percent per 100 m depth for chloride to 4 percent per 100 m depth for strontium.</p><p>The migration of ions in a thermal gradient (Soret effect) would cause minor salt enrichment upward toward the colder pole, but the presence of cation-exchanging particles such as clays would reverse this tendency and cause pumping of salt downward. A model calculation using literature data for the thermal potentials suggests that about 5-percent enrichment in Cl per 100 m depth may occur under steady-state conditions.</p><p>These mechanisms do not explain the greater enrichments commonly found in subsurface brines, but may modify salt distributions due to other phenomena.</p> application/pdf 10.1306/5D25CA1B-16C1-11D7-8645000102C1865D en American Association of Petroleum Geologists Role of gravity, temperature gradients, and ion exchange media in the formation of fossil brines article