Diffuse emission of carbon dioxide, methane, and helium‐3 from Teide Volcano, Tenerife, Canary Islands

Abstract

Diffuse emission of CO 2 , CH 4 and ³He was investigated in the summit crater of Teide volcano, Tenerife, Canary Islands. The results indicate that Teide volcano releases abundant CO 2 not only from its active crater, but also from its flanks as diffuse soil emanations. The spatial distribution of these emanations correlates quite closely with that of geothermal anomalies and manifestations. Our flux measurements indicate a total output of 380 ton·day −1 of CO 2 and 1.6 on·day −1 of CH 4 by diffuse degassing. From the ³He/CO 2 ratios and the CO 2 flux we estimate a diffuse ³He flux of 0.052 mol·year −1 . Isotopic analysis of carbon in soil gas samples from sites of high soil CO 2 flux indicates a magmatic origin for the CO 2 , also reported by high ³He/ 4 He ratios of 5.50 and 5.87 Ra. The origin of methane is more uncertain with low δ 13 C values suggesting a biogenic contribution.