First estimations of terrestrial heat flow in the TMVB and adjacent areas based on isotopic composition of natural helium.

The Transmexican Volcanic Belt is the most active zone of recent volcanism in Southern Mexico. However, only a few heat flow data have been collected in the region. In the present work a non-traditional approach is used to calculate terrestrial heat flow by means of the 3He/4He ratio in gases of geothermal origin. The data obtained delineate the main volcanic systems of the Belt and its limits.