Is neogenic chlorite responsible for the conductive basement in shield volcanoes of Reunion Island? A chemical modelling approach

摘要

Various hypotheses are proposed to explain the omnipresence of a conductive basement in oceanic shield volcanoes. We evaluate here the prime appearance of neogenic chlorite with depth, under the geothermal gradient, as a major factor of resistivity fall in basaltic formations 600 to 800 m beneath the volcano flanks. Results of chemical modeling are confronted to new geological data collected in Reunion Island volcanoes.