FT410. The San Andreas Fault through Gorgonio Pass

FT410. The San Andreas Fault through Gorgonio Pass

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Full title: Kirk Bryan Field Trip: The Holocene Trace of the San Andreas Fault through San Gorgonio Pass

Cosponsors: GSA Quaternary Geology and Geomorphology Division

Leaders: Richard Heermance, Nathan D. Brown, Andrew Cyr

Dates: Sat., 21 September 2024

Location: GSA Connects 2024, Anaheim, California, USA

Start Time: 7:30 AM

The San Andreas Fault bifurcates into strands through San Gorgonio Pass northwest of Palm Springs. Here, the Mission Creek Strand cuts through Mission Creek Preserve near Desert Hot Springs, where it cuts and/or is overlain by late Quaternary deposits. This field trip will visit locations along the fault within the preserve to decipher the late Quaternary and/or Holocene slip history, where slip rate estimates vary between 0 and >20 mm/yr among researchers. Sites are within ~2 km of the parking area. Site 1 will be a recently dated (OSL) Holocene terrace, which overlies or is cut by the Mission Creek Strand. Site 2 looks at the Mission Creek Strand where it forms an obvious lineation and bench along a canyon wall, where Quaternary sediment has been uplifted and exposed. Here we can observe the San Andreas Fault and discuss the timing of fault slip. Site 3 will be a right-laterally offset channel within Quaternary sediment west of Site 2, where we will discuss OSL dating of alluvial deposits. Specifically, we will discuss the syn- or post-tectonic origin of the inset alluvium. The field trip will depart from Anaheim and participants will be driven via SUV to the Stone Cabin at Mission Creek Preserve, where there are restrooms and a picnic area. From there, Site 1 is an easy 1-km walk. Site 2 will be another ~400-m walk up a low-gradient alluvial surface. Site 3 requires a relatively steep hike another 1000 m beyond Site 1 for those willing and able. Transportation, lunch, and snacks are included.

By purchasing this item, you are buying a seat on an in-person geological field trip

Students and Early Career Professionals: Apply for a grant to make this trip free, courtesy of GSA Divisions and a new partnership with Chevron.

Please review these Field Safety Documents. You will be contacted to provide your consent to these forms after purchasing a field trip.

Learn more about this and other field trips.

For additional information, please contact Rebecca Taormina, rtaormina@geosociety.org, GSA Field Trip and Short Program Coordinator.

Product Code: FT24CN410

Product Category: FTRIP

55.00