Alluvium, young
Alluvium, young
Holocene to late Pleistocene
Young fluvial deposits occurring within active channels, adjacent younger alluvial terraces, and active alluvial fans. Minimally consolidated and dissected; grain size is variable and includes gravel (pebble to cobble and rarely boulder), sand, silt, and minor clay. Composition is highly variable and dependent on source rock types. Locally includes undifferentiated glacial outwash, lacustrine, eolian, colluvial, and debris flow deposits. Includes Modesto Formation fluvial facies (Davis and Hall, 1959; Marchand and Allwardt, 1981) and many undifferentiated young alluvial units.