Presentation Title

REFINEMENT OF TECTONOSTRATIGRAPHY OF THE NORTH EAST BIG MARIA MOUNTAINS, RIVERSIDE COUNTY, CALIFORNIA

Faculty Mentor

Nicholas Van Buer

Start Date

18-11-2017 2:15 PM

End Date

18-11-2017 3:15 PM

Location

BSC-Ursa Minor 1

Session

Poster 3

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

The Big Maria mountains in the eastern Mojave, north of Blythe, California, contain the same Paleozoic stratigraphy as the Grand Canyon, which has been overturned and in some places attenuated to a tenth of its original thickness. The structure, nature, and timing of these events has been well documented; whereas, published maps lack the finer details of the stratigraphy and geology of the range. There are three rock units with undetermined ages, an augen gneiss, a quartz-epidote schist, and a fine grained quartzofeldspathic gneiss. The ages of these rock are estimated to be either Proterozoic or Mesozoic. They are concentrated in the northeast of the range and obscure the nature and extent of faulting and large-scale folding. Multiple approaches were used to resolve this issue. A map based on field data and satellite imagery was created with GIS software. Samples of pertinent units were collected and prepared for both X-ray fluorescence and optical petrography. Zircons were separated from samples of particularly complex geology for geochronology. Mapping has confirmed a second nappe within the range but did not clarify the chronostratigraphy of the units with undefined ages. Petrographic analysis reveals that nearly all samples exhibit epidote-amphibolite metamorphic textures and mineralogy and that the units are very similar in composition. Completion of XRF analysis and radiometric dating should clarify the origin of these rocks. Determining the ages and origin of them is necessary to refine the nature and extent of faulting in the Big Maria mountains and region.

Summary of research results to be presented

Mapping has confirmed a second nappe within the range but did not clarify the chronostratigraphy of the units with undefined ages. Petrographic analysis reveals that nearly all samples exhibit epidote-amphibolite metamorphic textures and mineralogy and that the units are very similar in composition. Completion of XRF analysis and radiometric dating should clarify the origin of these rocks

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Nov 18th, 2:15 PM Nov 18th, 3:15 PM

REFINEMENT OF TECTONOSTRATIGRAPHY OF THE NORTH EAST BIG MARIA MOUNTAINS, RIVERSIDE COUNTY, CALIFORNIA

BSC-Ursa Minor 1

The Big Maria mountains in the eastern Mojave, north of Blythe, California, contain the same Paleozoic stratigraphy as the Grand Canyon, which has been overturned and in some places attenuated to a tenth of its original thickness. The structure, nature, and timing of these events has been well documented; whereas, published maps lack the finer details of the stratigraphy and geology of the range. There are three rock units with undetermined ages, an augen gneiss, a quartz-epidote schist, and a fine grained quartzofeldspathic gneiss. The ages of these rock are estimated to be either Proterozoic or Mesozoic. They are concentrated in the northeast of the range and obscure the nature and extent of faulting and large-scale folding. Multiple approaches were used to resolve this issue. A map based on field data and satellite imagery was created with GIS software. Samples of pertinent units were collected and prepared for both X-ray fluorescence and optical petrography. Zircons were separated from samples of particularly complex geology for geochronology. Mapping has confirmed a second nappe within the range but did not clarify the chronostratigraphy of the units with undefined ages. Petrographic analysis reveals that nearly all samples exhibit epidote-amphibolite metamorphic textures and mineralogy and that the units are very similar in composition. Completion of XRF analysis and radiometric dating should clarify the origin of these rocks. Determining the ages and origin of them is necessary to refine the nature and extent of faulting in the Big Maria mountains and region.