New Mexico Geological Society Annual Spring Meeting — Abstracts

Heat flows in the Socorro area vary widely within relatively short distances, suggesting that uppermost crustal phenomena are responsible. Heat flows as high as 490 mW/m**2 are measured in the Socorro mountain block, while in La Jencia Basin (less than 10 km west) heat flows below 30 mW/m**2 are observed (regional heat flows average 75-100 mW/m**2. Low heat flows in La Jencia Basin are probably caused by downward ground-water flow. We suggest that ground water flowing eastward in the basin subsurface is constrained to move downward into deeper aquifers by low permeability clays and claystones in the eastern part of the basin. Percolation of hydrologic recharge down from the surface may also influence heat flows, but we believe this is a relatively minor effect.

High heat flow in the Socorro mountain block may be caused by either an upper crustal heat source (such as magma), and/or upward ground-water flow. We suggest that upIward ground-water flow is a major influence, if not the entire cause of the high heat flows. High heat flows coincide with upfaulted blocks of permeable fractured volcanic rocks, which are located 'downstream' from thick, relatively impermeable, claystone units. These upfaulted blocks act as hydrologic windows allowing confined groundwater to flow upward, elevating near surface heat flows.

Finite difference modeling demonstrates that the hydrologic phenomena we postulate are, in fact, consistent with the hydrogeology of the Socorro area. In addition, modeling also demonstrates that such hydrologic phenomena can produce anomalous heat flows of the magnitudes and relative locations observed in the Socorro area.