385 D41. Structural Geology (Posters): Analysis of Faulting, Deformation and Flow

Wednesday, 25 October 2017
9:00 AM - 6:30 PM
Halls 4EF

MAPPING MAGMATIC FLOW VIA ENCLAVE DEFORMATION IN THE THREE SISTERS ANDESITE: EL PASO, TEXAS

Paper number: 385-2
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

  • Shannon E Brink Presenting Author
    University of Wisconsin Baraboo/Sauk County, Baraboo, WI

Abstract

Three Sisters is an Eocene aged trio of andesitic hills located in El Paso, Texas containing enclaves. Enclaves are compositionally distinct aggregates of minerals found within a host rock due to magma mixing and crystal fractionation. The orientations, plunge and dimensions of these enclaves indicate the direction of flow within a magma body. By documenting and studying the trend and plunge of enclaves over an igneous body, a flow pattern can be seen. When analyzed in conjunction with a geologic map, the reasoning for the route of intrusion can be found. Our flow maps contain variable alignment patterns, which can be attributed to shortened dimensions accessible from an outcrop view as well as the presence of compositionally-identical xenoliths (which are potentially less affected by shear). Various stereonets and flow maps flush out trends based on the composition as well as the location of the enclaves found in the hills. The composition of enclaves may be utilized to determine a velocity range of the churning and ascending magma body due to a difference in interfacial tension between enclaves of differing compositions and the host, this can allow for location of convection cells, which gives further insight into the mechanics of magma bodies.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-308379

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