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Full-Text Articles in Physical Sciences and Mathematics
Chronicling Magma Transit Beneath Hawaiian Volcanoes: Every Isotope A Word, Every Crystal A Story, Jonathan Pinko
Chronicling Magma Transit Beneath Hawaiian Volcanoes: Every Isotope A Word, Every Crystal A Story, Jonathan Pinko
UNLV Theses, Dissertations, Professional Papers, and Capstones
At many oceanic volcanoes, such as Hawaii, mantle-derived magmas migrate to crustal level magma chambers, where they accumulate before eruption. Understanding the magma chamber residence times, or the time gaps between the arrivals of new magmas and eruptions, is important in volcanic hazard mitigation. Here I apply iron and magnesium isotope effects in olivines to constrain these times at Hawaiian volcanoes. Combined with published data, I present bulk ?56Fe (-1.706 to 0.489) and ?26Mg (-0.400 to 0.356) in 108 Hawaiian olivines erupted from the pre-shield, shield, and post-shield stages. The Hawaiian olivine ?56Fe and ?26Mg represent the largest Fe-Mg isotope …
Carbon Isotope Variations Associated With A Middle Ordovician Karstic Unconformity, Patricia Suzanne Williams
Carbon Isotope Variations Associated With A Middle Ordovician Karstic Unconformity, Patricia Suzanne Williams
UNLV Theses, Dissertations, Professional Papers, and Capstones
Large negative carbon isotope (δ13C) excursions have been documented from late Neoproterozoic-Paleozoic successions. These δ13C excursions have been widely used for regional and global stratigraphic correlation, particularly in strata with limited paleontological and radiometric age controls. Recent studies, however, argued that some negative δ13C excursions from stratigraphic record may have been resulted from meteoric/burial diagenesis, which commonly shifts both carbon and oxygen isotopes toward lower values. Testing the diagenetic origin of δ13C excursions in stratigraphic successions without independent stratigraphic framework has been difficult because it evolves into circular arguments about stratigraphic completeness …