Morphometric age and petrological characteristics of volcanic rocks from the Bajawa Cinder Cone Complex, Flores, Indonesia

Abstract

The Bajawa Cinder Cone Complex consists of at least 78 cinder cones, which can be grouped into five morphometric ages. The oldest group, Bajawa 01, is dated between 0.53 and 0.73 Ma. The groups Bajawa 02, 03, and 04 have an age range from 0.41 Ma to 0.51 Ma, 0.32 Ma to 0.40 Ma, and 0.22 Ma to 0.31 Ma, respectively; the youngest cinder cone group, Bajawa 05, is aged between 0 and 0.20 Ma.
    Three batches of magma have contributed to the long eruptive episode of the complex. Magma mixing and fractional crystallization were important processes in differentiation. Magma mixing may have been caused by recharge of a mafic contributor to form a mixed magma in a temperature range of 836 °C-978 °C and at a pressure of less than 1.25 kbar before eruption.