Prior to eruption at mid-ocean ridges, melts must travel through >6 km of crust from their origin in the mantle. The final composition of the melts is dependent on both the melting conditions and magmatic processes within the crust. While mid-ocean ridge basalt (MORB) glasses are commonly used to infer...
Three broadly interrelated problems of critical significance to the proper interpretation of melt inclusion (MI) data are addressed in this thesis. The first issue, the petrogenesis of anorthitic plagioclase phenocrysts in MORB lavas, has relevance due to the presence of numerous MI in many high-An feldspars. This problem was addressed...
Magmatic processes control the chemical compositions of all lavas erupted at
mid-ocean ridges. In this thesis, I present studies of magmatic processes on three
different mid-ocean ridges to determine which processes are in action and to what extent
each has affected the chemistry of mid-ocean ridge basalts at each location....
To understand the processes that lead to the formation of the oceanic crust, one must know the composition and the depth at which primary melts originate. Towards this end, this dissertation focuses on plagioclase-hosted melt inclusions from plagioclase ultraphyric basalts (PUBs). Plagioclase is usually considered to be the second phase,...
Snow Peak is a voluminous shield volcano located ~50 km west of the axis of
the modern Cascade arc. A previously published K-Ar age estimate indicates that the
Snow Peak lavas are ~3 Ma. Subsequently, the preliminary research framework for
studying the Snow Peak lavas focused on constraining the petrogenesis...
The primary goal of this study is to assess the impact of a subduction component
added to the mantle wedge beneath the Oregon Cascades to the composition and fO2 of
primitive Cascade basalts. Olivine-hosted melt inclusions from compositionally diverse
basalts across the Cascade arc (~100 km) are utilized in an...
