| State | California |
|---|---|
| Name | Older Quaternary alluvium and marine deposits |
| Geologic age | Pleistocene |
| Lithologic constituents |
Major
Unconsolidated > Coarse-detrital (Alluvial, Terrace, Bed)
Minor
Unconsolidated > Fine-detrital (Lacustrine, Bed)
|
| Comments | from the 2010 data source metadata: The depiction of Quaternary geologic units on the original map by Jennings (1977) was simplified by the author who noted that "various surficial deposits of Quaternary age are lumped into the unit 'Q'." Since Jennings' work, subdivisions of these deposits have been found to have very different potential for liquefaction and for amplification of seismic shaking. Relative age of Quaternary alluvial fan deposits have also been found to correlate with potential for flooding. Since these units are important for evaluation of geologic hazards, the 2010 update of the geologic map includes a subdivision of Jennings "Q" into younger alluvium "Q" and older alluvium "Qoa". |
| References | Jennings, C.W., with modifications by Gutierrez, C., Bryant, W., Saucedo, G., and Wills, C., 2010, Geologic map of California, Version 2.0 (California Geological Survey 150th Anniversary Edition), Department of Conservation, California Geological Survey: California Geologic Data Map Series, GDM No. 2, scale 1:750,000. |
| NGMDB product | |
| Counties | Alameda - Butte - Colusa - Contra Costa - Del Norte - Fresno - Glenn - Humboldt - Imperial - Inyo - Kern - Kings - Lake - Lassen - Los Angeles - Madera - Marin - Mendocino - Merced - Modoc - Monterey - Napa - Orange - Plumas - Riverside - Sacramento - San Benito - San Bernardino - San Diego - San Joaquin - San Luis Obispo - San Mateo - Santa Barbara - Santa Clara - Santa Cruz - Shasta - Sierra - Siskiyou - Solano - Sonoma - Stanislaus - Tulare - Ventura - Yuba |