Lake Mary Fault Zone 2002 Advanced Field Geology Assignment

Due Date: Monday April 21 5:00 pm For this assignment, please turn in the following:

1) Your neatly drafted and compiled map for the Walnut Canyon (2nd day) portion of our mapping effort. See Jeri or the drafting table in F475 for copies of the base map for compilation (also downloadable as 300 dpi tiff from here: LMBase.tif (30 Mb) or EPS (open in Illustrator): LMBase.eps)

2) Your neatly drafted log of the exposure from the Observatory Road site.

3) A narrative of less than 5 pages length to accompany the above figures that addresses the following (% refers to approximate relative weight of each component):

a) Describe the mapping of the Lake Mary Fault zone in the Walnut Canyon area (refer regularly to features on your map). How is the Lake Mary Fault manifest? What is the sense of offset along it and do you have any even rough estimate of the magnitude of offset? What are the secondary structures along it and what does the bedding do? Are any of the Quaternary surfaces affected? Do you find any evidence for recent activity along the Lake Mary Fault in Walnut Canyon? (50%)
b) Choose a site along the Walnut Canyon reach of the Lake Mary Fault where an excavation would probably best be situated in order to evaluate the effect of faulting on younger (Qal) units in the sense of the exposure we logged at the Observatory Road. Locate this site on your map and provide a 1 paragraph justification for the location. (10%)
c) Describe the Observatory Road outrop sedimentary and soil textures and relationships as depicted in the log. Refer to any other observations of the hillslopes or roadcuts in the area around the exposure. How do you think the features in the log formed? In other words, is there evidence for faulting there? How could faulting fit into a sequence of events that developed those relationships? (40%)

Pages maintained by Ramón Arrowsmith
April 13, 2003