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Full-Text Articles in Physical Sciences and Mathematics
Petrology Of An Oxidized Blueschist Cobble From The San Onofre Breccia, California, Usa, Alaina A. Helm
Petrology Of An Oxidized Blueschist Cobble From The San Onofre Breccia, California, Usa, Alaina A. Helm
Honors Papers
The mid-Miocene San Onofre Breccia (SOB) found along the southern California borderlands contains clasts of several lithologies including high-pressure metamorphic rocks commonly thought to be shed from the Catalina Schist. Sorensen concluded the San Onofre Schist was part of the Franciscan Complex, although at that time the Catalina subduction was considered to be part of the Franciscan Complex. In this study, a ~10 cm cobble collected from the San Onofre type locality was studied to describe its mineralogy and estimate its conditions of metamorphism. The cobble is composed of glaucophane (35%) + epidote (15%) + garnet (13%) + phengite (12%) …
Eclogites And Eclogites: Oxygen Isotope Evidence Of A Shared Subduction Origin For Franciscan Eclogites And Moses Rock Eclogite Xenoliths, William F. Hoover
Eclogites And Eclogites: Oxygen Isotope Evidence Of A Shared Subduction Origin For Franciscan Eclogites And Moses Rock Eclogite Xenoliths, William F. Hoover
Honors Papers
Eclogites can be found in two distinct tectonic settings in the western USA: in the Franciscan Complex as tectonic blocks in a fossil accretionary wedge, and in the Navajo Volcanic Field as xenoliths in diatremes. Intra-crystal oxygen isotope analyses of garnets from these two settings provide important information on the source, composition and timing of fluid interactions in both eclogite settings. Because of the well-documented relationship between Franciscan subduction and the volcanism in the Navajo Volcanic Field, the samples in this study can be directly compared to determine if they share a common origin. The Navajo eclogites in this study …
Thermobarometric Modeling Of The Catalina Amphibolite Unit: Implications For Tectonic And Metasomatic Models, Henry W. Towbin
Thermobarometric Modeling Of The Catalina Amphibolite Unit: Implications For Tectonic And Metasomatic Models, Henry W. Towbin
Honors Papers
On Santa Catalina Island, Ca high-grade amphibolite units overlie progressively lower- grade blueschist units in an inverted stack structure. This juxtaposition of high grade and low-grade metamorphic units has long been the subject of much debate as to the tectonic origins of the formation and how it relates to California's tectonic evolution. Previous petrography and thermobaromety of blocks in the amphibolite unit estimate pressures and temperatures of ~8-11 kbar and ~640-750 °C (Platt, 1975; Sorensen and Barton 1987). These estimates were calculated before many of the computational advances in modern thermobarometry. Using Equilibrium Assemblage Diagrams (EAD) calculated with Theriak Domino, …