Magmatic history of lavas from Kilauea volcano, Hawai'i and South Pagan volcano, Northern Mariana Islands

Petrologic and geochemical time-series studies of active volcanoes yield valuable insight into the crustal processes (e.g., crystal fractionation and accumulation, and crustal assimilation) and mantle source and melting variations (e.g., mantle source heterogeneity, and melt production, extraction, and transportation). This dissertation is composed of three main projects related to the magmatic history of lavas from Kilauea Volcano, Hawai'i and South Pagan Volcano, Northern Mariana Islands. These volcanoes are highly active providing an excellent opportunity to investigate the magmatic processes that operate in both infra-plate (Kilauea) and island-arc (South Pagan) settings over timescales of hours to thousands of years. Here, I present a comprehensive petrologic evaluation of: (1) 1998--2005 Pu'u 'O'o lavas from Kilauea's east rift zone (Chapter 1); (2) Quaternary to Holocene lavas from two volcanoes in South Pagan (Chapter 2); and (3) Historical (1790--1980 A.D.) K ilauea rift lavas (Chapter 3) using Pb, Sr, and Nd isotope ratios, major and trace element abundances, olivine compositions, and petrographic data. Chapter 1 discusses the compositional evolution of 1998--2005 Pu'u 'O'o lavas and the implications for the nature and scale of mantle source heterogeneity within the Hawaiian plume. Chapter 2 examines the chemistry of stratigraphically-controlled southern Pagan lavas to assess and identify the slab contributions (fluid and sediment components) involved in arc magma genesis, determine the nature and extent of mantle partial melting, and evaluate crustal magmatic processes beneath Mariana volcanoes. Chapter 3 investigates the temporal geochemical variations of historical Kilauea rift lavas to examine the petrogenetic relationship between summit and rift parental magmas, evaluate the magmatic link between the summit and rift zones, and determine the timescales of magma transport, mixing, and differentiation processes within the shallow plumbing system.