Earth-surface effects on the temperature distribution in the earth's crust due to magma intrusion

We have carried out a 2-D analysis for the isotherm evolution resulting from the intrusion of a hot dike in a cold rock, including earth-surface effects. Our analysis differs from previous analysis in that we include the influence of the earth surface in the isotherm evolution. The analysis in this case is more complex than in the usual 1-D case. A relatively simple solution has been found despite the additional complexity due to the depth dependence. The analysis carried out leads to analytic solutions for the isothermal evolution in time. A good view of this evolution is given by the curve envelope of the isothermals. One of the aims of this analysis is to determine the location of gold veins in the Callao mines, Venezuela. The 400°C and 500°C isotherms have been studied in detail because of their importance for the determination of the gold-vein sites. One important difference between our analysis and previous 1-D treatments is that our analysis shows that the isotherms move further away from the dike with depth-a result borne out by mapping in the Callao mines. © 2002 Society of Exploration Geophysicists.