Volcano–tectonic structures, gravity and helium in geothermal areas of Tuscany and Latium (Vulsini volcanic district), Italy

Since the early 1980s, geological and structural mapping, gravity, and helium soil±gas studies have been performed in the eastern sector of the Vulsini Volcanic District (Roman Magmatic Province) in an attempt to locate potential geothermal reservoirs. This area is characterised by an anomalous geothermal gradient of >1008C/km, and by widespread hydrothermal mineralization, thermal springs, high gas ¯uxes, and fossil and current travertine deposits. The results of these surveys indicate the existence of a number of fault systems, with N±S and E±W structures that appear to be superimposed on older NW±SE and NE±SW features. Comparison of the results of the various studies also reveals di€erences in permeability and potential reservoir structures at depth. # 1999 CNR. Published by Elsevier Science Ltd. All rights reserved.