Type of Submission
Poster
Keywords
Independence Dike Swarm, petrology, geochemistry, mineral alteration
Abstract
Petrologic studies are important because they provide insights into the conditions under which rocks form. The Late Jurassic Independence Dike Swarm is a series of vertical igneous dikes that crop out in eastern and southern California, and range from mafic to felsic in composition. In order to examine their petrology and geochemistry, surface samples were collected from four different dike outcrops within Owen’s Valley, CA. The samples were examined through thin-section analysis under a petrographic microscope, X-ray diffraction analysis, and X-ray fluorescence analysis. Mineral composition, mineral size, major, trace, and rare earth element concentrations were collected from these analyses. Results from all samples were compared. Petrologically, the dikes range in classification from gabbro to diorite to granite, with the more gabbroic and dioritic dikes having larger concentrations of plagioclase. The more granitic dikes have larger concentrations of quartz and potassium feldspars. There is considerable mineral alteration, especially among the feldspars, with some of the samples having been almost completely altered into clay minerals. The presence of epidosite within a dike suggests the source magma incorporated country rock on the way toward the surface. Geochemical analysis shows chemical variability among the dikes and possible source magma differentiation within the Owen’s Valley area.
Campus Venue
Stevens Student Center
Location
Cedarville, OH
Start Date
4-20-2016 11:00 AM
End Date
4-20-2016 2:00 PM
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
The Petrology and Geochemistry of the Independence Dike Swarm, Owen’s Valley, California
Cedarville, OH
Petrologic studies are important because they provide insights into the conditions under which rocks form. The Late Jurassic Independence Dike Swarm is a series of vertical igneous dikes that crop out in eastern and southern California, and range from mafic to felsic in composition. In order to examine their petrology and geochemistry, surface samples were collected from four different dike outcrops within Owen’s Valley, CA. The samples were examined through thin-section analysis under a petrographic microscope, X-ray diffraction analysis, and X-ray fluorescence analysis. Mineral composition, mineral size, major, trace, and rare earth element concentrations were collected from these analyses. Results from all samples were compared. Petrologically, the dikes range in classification from gabbro to diorite to granite, with the more gabbroic and dioritic dikes having larger concentrations of plagioclase. The more granitic dikes have larger concentrations of quartz and potassium feldspars. There is considerable mineral alteration, especially among the feldspars, with some of the samples having been almost completely altered into clay minerals. The presence of epidosite within a dike suggests the source magma incorporated country rock on the way toward the surface. Geochemical analysis shows chemical variability among the dikes and possible source magma differentiation within the Owen’s Valley area.
