AbstractsEarth & Environmental Science

Petrology and geochemistry of boninites and related lavas from the Mata Volcanoes, NE Lau Basin

by Sarah Elizabeth Glancy




Institution: University of Hawaii – Manoa
Department:
Year: 2015
Keywords: Mata Volcanoes; Lau Basin
Posted: 02/05/2017
Record ID: 2064777
Full text PDF: http://hdl.handle.net/10125/101076


Abstract

M.S. University of Hawaii at Manoa 2014. The Lau Basin is an excellent location for studying suprasubduction zone processes due to numerous volcanoes spanning from the forearc, arc, reararc, to backarc settings, providing windows into different aspects of the subduction zone. The young, primarily boninitic submarine Mata Volcanoes, located between the arc and the backarc spreading center, are an important part of this picture. This thesis presents a preliminary study of the Mata Volcanoes, including XRF whole rock and glass, and mineral EPMA analysis of samples, thermometry, and crystallization modeling. Differentiation at the Mata Volcanoes occurred under oxidizing conditions, and over a temperature range of approximately 1000-1200 ⁰C. Starting magmas had high water contents of at least 1.7-2 wt%. Lavas preserve heterogeneities, suggesting that no well-developed magma storage system/homogenization zone is present. Complex crystal chemistry and compositions suggest that magma mixing played a role in the formation of these magmas.