difference of temperature of caldera forming felsic magma

Abstract

Using the CL images and Ti concentrations of quartz, we estimate magma temperatures. (1)We compare the Obirakiyama tuff mainly contains two types of quartz bearing pumice clast (Bt-type and Hb-type; Kudo et al.,2007). CL images of Bt-type quartz crystals are almost uniform (710C). In contrast, Hb-type quartz crystals has darker core (750C) with brighter rim(800C). It is concluding that only Hb-type magma has recharged mafic magma its triggered eruption. (2)There is a across arc variation of the caldera forming felsic magma. Chijimisawa tuff (volcanic front region) has higher temperature (40-90C) than Obirakiyama tuff (back arc region).