9614670 Morrison Results from a laser-based oxygen isotope pilot study of four textural varieties of epidote in the Mt. Lowe intrusion of southern California indicate that oxygen isotope compositions of epidote and adjacent phases can be used to distinguish magmatic from subsolidus epidote. The PIs will conduct a combined petrographic, petrologic and laser-based oxygen isotope study of epidote from eight different well documented epidote-bearing plutons to assess the reliability of the textural criteria that are commonly used to distinguish magmatic from subsolidus epidote. The Mt. Lowe intrusion and other epidote-bearing intrusions will be studied. Detailed textural characterization, thermobarometry and laser-based oxygen isotopic analyses will be conducted.
