SYNCHRONOUS GEOMORPHIC RESPONSE TO HOLOCENE CLIMATE CHANGE IN THE CARRIZO PLAIN, CALIFORNIA
By 3.3+/-0.2 ka (TL date), Soda Lake had become hypersaline and a 9.5-km long clay dune had grown along its eastern and southern limits. With the cooler and wetter climate that followed, the average lake level began to rise and reached a high stand (2.9-2.6 ka). During this same period, channel incision occurred at Wallace Creek (after 3.7 ka), the small channels nearby, and the Phelan Creeks (3.5-2.5 ka). With higher lake levels, the clay dune system was stabilized and underwent a period of erosion and soil formation. The average level of Soda Lake dropped precipitously at ~2.1 ka and then remained relatively low. This interval was characterized by stability in the fluvial systems. A short-lived slightly higher lake level occurred at the same time that incision occurs in the small channels (1.35 ka). The other drainages were stable. The average lake level remained low until the modern level was achieved at 0.8 ka. Incision occurred at Phelan Creeks about 0.5 ka. Most of the dune complex is now eroding. Fluvial, aeolian, and lacustrine processes of this closed system show synchronous response to climate change as recorded by channel incisions and dune stability during high lake level and channel stability and dune formation during low lake level.