Catalina fault field trip assignment
Due date: Thursday, March 19, 2009
- Compile all of your geological mapping of the faults and attitude observations onto the map provided: Simple geology with profile location on contours. You can do this by hand or in the computer. Make sure to use standard symbology and provide an explanation. Mark the geologic units (PzLs, fault rocks if mapped, and brecciated and unbrecciated mylontici gneiss) as well by label or color.
- Produce a geologic cross-section on the topographic profile provided. Blue dots are at intersections with Catalina and Javalina Faults. Determine strike and dips from the intersections of the contacts with topography or use your measurements. Use representative values (either your best ones, the closest ones to the line of section, or an average). Make sure to compute the apparent dip of the planar feature in the vertical plane of the cross section. Use observations from the field and geological intuition to complete the profile. Be sure to use standard patterns to help evoke the geologic relationships and rock units graphically.
- Writeup (2-3 pages; all parts will need to be brief and compact):
- Short paragraph on project overview
- Rock descriptions for the major units
- Narration of geologic map relationships
- Discussion of cross-section production procedures and assumptions
- Based on on the cross section, geologic map, and your field observations (include all we observed and the asserted Javalina Fault), what are the structural changes you note as you approach (from below) and cross the Catalina fault? Highlight the ductile and brittle features and how these deformation modes are manifest. Which mode of deformation is younger (what is the evidence), and where is each dominantly preserved?
- Looking at the readings, briefly discuss how your observations and synthesis compares with the core complex/detachment fault models presented?
Chapter 9 (shear zones) and portions of chapter 6 on fault rocks from Davis and Reynolds, 1996, Structural geology of rocks and regions
Spencer, J. E., and Reynolds, S. J., 1989, Middle tertiary tectonics of Arizona and adjacent areas, in Jenney, J. P., and Reynolds, S. J., Geologic evolution of Arizona: Tucson, Arizona Geological Society digest 17, p. 539-574.
Last modified: March 4, 2009