Origin of Eocene Granitoids in Prince William Sound, Alaska

By Emily Johnson
Whitman College, Walla Walla WA

Magmatism along the coast of south-central Alaska is attributed to the west-to-east subduction of a mid-ocean ridge spreading center between 51 and 60 million years ago.  An anomalously young suite of 35-40 million-year-old igneous rocks in Prince William Sound does not fit easily into this tectonic model.  Field and microscopic observations indicate that magma mixing is likely a major process during the emplacement of these intrusions.  The origin of the magmas themselves is as yet unconstrained thus examination of geochemical results will shed light on the relationship between the tectonic setting and the formation of the parental magmas of these rocks. 

The Keck Geology Consortium and the National Science Foundation funded this research opportunity. Whitman faculty sponsor Kirsten Nicolaysen.