New heat flow data and recent relative Vs (ΔVs/Vs) studies suggest differential crustal warming from prolonged intrusions in the Socorro magma body area. Heat flow above the Socorro magma body, relative to the adjacent Colorado Plateau and Datil-Mogollon region, indicates that ∼8 times more heat has been introduced into the crust than contained in a basaltic Socorro magma body. A combination of relative Vs contours and heat flow data suggests this differential is less, a factor ∼4.5. From relative Vs contours, depth of Socorro magma body, and conduction time constants, the minimum time required to increase heat flow resulting from midcrustal intrusions is ∼1–3 m.y. Recent models indicate that observed historic uplift at the Socorro magma body is explained by viscoelastic response of crustal material surrounding the Socorro magma body. Our estimates suggest that a long time scale (∼106 yr) for emplacement of basaltic magma sill(s) and surface uplift need not be directly related. Based on heat flow, we estimate >600 m of basaltic intrusion during Pliocene–Pleistocene time. Compared with adjacent rift basins, the Socorro magma body area shows anomalous landscape instability but no significant uplift of stream terraces across the magma body. Contiguous areas in the Rio Grande Rift have high heat flow but no present magma layer, no historic uplift, and little seismicity. Elliptical relative Vs crustal contours for the area suggest conductive heat transfer. The relative Vs model implies that the Socorro magma body is fed by narrow conduits (dikes) from the upper mantle and that the depth of the sill-like Socorro magma body is primarily controlled by rheology.
- Received 8 June 2010.
- Revision received 25 August 2010.
- Accepted 27 August 2010.
- © 2010 Geological Society of America