Geochemistry of Calc-alkaline Volcanic Rocks in relation to deep Structure of Ecuador and Southern Colombia

Resumen

Geochemistry of 104 samples of young volcanic rocks from the Western and Eastern Cordilleras of Ecuador and Southern Colombia was correlated with the deep structure of the region between parallels 1.5°N and 2°S and meridians 77°W and 79°W. The geochemical zonation of volcanic products was confirmed in dependence on the depth of the primary source of calc-alkaline magma in the partially melted part of the subduction zone. It was found that the contents of K 2 O, U, Th, Rb, Sr, Ba, Zr, V, TiO 2 and P 2 O 5 in andesites significantly increase with the depth of the upper boundary of the intermediate depth aseismic gap in the Andean Wadati-Beniof zone