| Fluvial fans in the San Joaquin Valley, California are composed of multiple sediment sequences separated by unconformable surfaces (Weissmann, 1999; Weissmann et al. 2002). The individual sequences are composed of channel, overbank, and pedogenically altered sediments. The pedogenically-altered deposits (paleosols) are believed to be (1) laterally continuous sequence stratigraphic bounding unconformities and (2) continuous with the exception of discrete breaks caused by paleochannel activity during glacial times. Using ground-penetrating radar and digitized county soil surveys on the Kings, Merced, and Tuolumne River fluvial fans we show that the Riverbank paleosol is a regionally laterally continuous feature and that discrete erosional breaks due to paleochannel activity do exist in the Kings River fluvial fan. Erosional breaks were not identified in the Merced or Tuolumne River fluvial fans. It is believed that a number of different factors including, basinal subsidence differences, stream base-level, Sierran drainage area, and sediment supply play a role in the morphological differences observed between the Kings, Merced, and Tuolumne River fluvial fans. |
