Helium-3 Distribution in Western Turkey

Abstract

In this study, to investigate the mantle-crust interaction in Western Turkey, geothermal fluids from various locations are analyzed for their 3He/4He ratios. The results reveal a mixing between mantle - and (continental) crustal - helium components. The distribution of mantle-helium, which is characterized by high 3He/4He ratios, does not show any correlation with the spatial and/or temporal distribution of the surface volcanics in the region, but appears to be governed by the distribution of tectonic deformation. The lack of any correlation between the distribution of mantle-helium and surface volcanism suggests that helium, now degassing from mantle, has most probably entered the crust in association with the melts emplaced at deeper levels. The fault systems of the present extensional tectonics are thought to have had an efficient role in the escape of helium to the surface through the brittle parts of crust.