Geothermal zones get close scrutiny



A recent study of the interaction of groundwaters and brines with magma-heated zones in the crust could result in a number of far-reaching geophysical implications if the conclusions reported by J.C. Dunn and H.C. Hardee are correct (J. Volcanol. Geotherm. Res., 11, 189–201, 1981). Fluid convection in near-critical aqueous groundwater solutions is strongly enhanced, resulting in significantly enhanced heat flow. Single- and two-phase flow may lead to processes that cause shallow pooling of magma in the crust. The solutions are chemically active and could initiate formation of extensive hydrothermal ore deposits. Geophysical data and experimental values make it possible to predict depths to superconnecting zones in the crust. Improved heat transfer in these zones could be responsible for the development of geothermal fields in the southwestern United States and other areas in the world that overlie shallow magma zones.