HE-3 EMISSION IN AND AROUND TEIDE VOLCANO, TENERIFE, CANARY-ISLANDS, SPAIN

Air corrected He-3/He-4 ratios of fluid samples collected in and aroun d Teide volcano, Tenerife, Canary Islands, ranged from 5.97 to 8.06 Ra . Helium-3 emission spatial distribution has a quite different pattern from other stratovolcanoes which show commonly a decreased trend for the He-3/He-4 ratio with respect to distance from the summit crater. T his finding might be related to the volcano-tectonic setting differenc es between subduction-type and oceanic island-type statrovolcanoes. Ra diogenic helium production is a significant process for the dilution o f uprising derived-mantle fluids in and around subduction-type stratov olcanoes while it can be almost negligible for polygenetic volcanoes a t oceanic islands.