Characterization of the La Reforma Mini Basin and Range Province, and constraining the nature of the Seri Tahue terrane boundary, Tasajeras Quadrangle, northwestern Mexico

Conor Correll McDonough, University of Texas at El Paso

Abstract

The region selected for this study is northwestern Mexico more specifically in Sinaloa located just south of the area of the intersection of the three states Sinaloa, Sonora, and Chihuahua. The area was chosen for study because of unique structural, isotopic, and geophysical properties, and the tectonic implications of these properties. Detailed field mapping and structural analysis using Landsat ETM + and SRTM DEM imagery show a strong NNW structural grain caused by high angle listric faults and dike formation, which are bounded by low angle WNW structures. Recent isotopic studies of the geographic distribution of initial 87Sr/86Sr, eNd and REE of the batholith suites in northwestern Mexico, along with the compilation map created in this study support the existence of a crustal discontinuity, possibly a terrane boundary. Results from the thermobarometric study on the Sinaloa batholith based on Al-in-hornblende and hornblende-plagioclase thermometry suggest a shallow emplacement depth with temperatures below solidus (655–700°C). The models for the crustal density and thickness derived from gravity describe the map region as a transition zone from relatively thin crust (20–30 km) to thick crust (40–50 km) with densities between 2.8 and 3.3 g/cm 2. This transition zone is marked by cratonic to non-cratonic isotope, magnetic, and gravity signaturs. ^

Subject Area

Geology

Recommended Citation

McDonough, Conor Correll, "Characterization of the La Reforma Mini Basin and Range Province, and constraining the nature of the Seri Tahue terrane boundary, Tasajeras Quadrangle, northwestern Mexico" (2005). ETD Collection for University of Texas, El Paso. AAI1425891.
http://digitalcommons.utep.edu/dissertations/AAI1425891

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