New Mexico Geological Society Annual Spring Meeting — Abstracts

We propose a new model for emplacement of the Socorro Magma Body (SMB) that is based on numerical models of crustal deformation as a result of sill emplacement, and supported by (geophysical) data. In this model, the SMB was emplaced in the last few hundred years at the brittle-ductile transition, and has been injected with magma in recent decades. The sill is imaged as a liquid body with seismic data, and in order for it to be detectable as liquid, our models predict that it needs to be younger than ~500 years. Thermal expansion as a result of sill emplacement results in a surface uplift pattern that is not compatible with observations; surface uplift is in agreement with inflation as a result of recent magma injection pulses. Sill inflation results in tensional crustal stresses above ~13 km depth that are large enough to cause tectonic earthquakes, in agreement with seismic data. This results in an apparent brittle-ductile transition at depths shallower than the sill.