120 likes | 225 Views
Ultra-High Pressure (UHP) rocks of the Cordillera Septinrional, Dominican Republic. Bonnie N. Broman Appalachian State University. BACKGROUND:.
E N D
Ultra-High Pressure (UHP) rocks of the Cordillera Septinrional, Dominican Republic Bonnie N. Broman Appalachian State University
BACKGROUND: • The Cordillera Septintrional, which consists of metamorphic and igneous basement rocks overlain by Miocene-Eocene siliciclastic and carbonate rocks, is located in the northern part of the Dominican Republic • Stratigraphic windows (inliers) of metamorphic and igneous rocks are exposed in various places such as the Rio San Juan (RSJ) complex
Within the RSJ, are three rock types of particular interest in regards to magma genesis:garnet peridotite, garnet clinoproxenite, and corundum bearing garnet clinnopyroxenite (composed of clinopyroxene, garnet, spinel, corundum and secondary hornblende with evidence of a magmatic origin) Garnet Clinopyroxenite Garnet Peridotite
Corundum-bearing Garnet Clinopyroxenite thin-section
RESEARCH GOALS: • To determine Pressure and Temperature conditions under which these rocks form
METHODS: • Field work which consisted of collecting samples and looking at relationships within the boulders in the Dominican Republic
Analyze our samples using the SEM and EDAX • SEM PROCESS: • We obtained homogenous natural mineral standards to analyze and compare to the samples we collected • Analyze sample DR03-12b which is the corundum-bearing garnet clinopyroxenite to determine the exact composition of the minerals, mainly garnet, clinopyroxenite, spinel, and corundum • Collected data for garnet, and clinopyroxene using our standards SEM image of garnet standard SEM image of augite standard
DATA: Example of Garnet analysis
REMAINING WORK: • Normalize analyses • Determine pressure and temperature conditions at which the compositions of these minerals are stable