Eichelberger/Faust The primary goal of this collaborative research between Franklin & Marshall College and the University of Alaska, Fairbanks is to understand processes in composite magma chambers that lead to compositional stratification, magmatic enclaves, and hybridization. The approach aims to reconcile the apparently conflicting insights from plutonic studies of magma chamber processes with insights from the study of active volcanic systems. Specific links will be established between comparable processes in plutonic and volcanic systems, for example, understanding the formation and fate of magmatic enclaves. The research will involve field, petrologic and geochemical studies of magmatic complexes where contemporaneous plutonic and volcanic rocks occur: (1) a Silurian complex on Vinalhaven, Maine, and (2) a Miocene complex on Unalaska Island, Alaska. Analytical work will also be conducted on composite late Holocene volcanic systems, where the pristine character of glasses in enclaves, host lavas, and melt inclusions can be exploited to trace melt histories during magmatic encounters. There are two broader problems upon which this work bears. One is the issue of the triggering of eruptions and subsequent eruptive behavior (explosive vs. effusive) - How does input influence output? The second is a part of the classic problem of igneous petrogenesis - Are the causes of chemical heterogeneity in large-volume eruption products and in plutons to be sought in in-situ differentiation in the source or host chamber, or in deeper, separate magma sources?
