WAS THERE A PLIOCENE-PLEISTOCENE FLUVIAL-LACUSTRINE CONNECTION BETWEEN DEATH-VALLEY AND THE COLORADO RIVER

Since the turn of the century, a Pliocene-Pleistocene connection between the Death Valley-Owens River pluvial system and the Colorado River drainage basin has been frequently postulated. The two most commonly proposed routes involve (1) a southward overflow from the Death Valley Lake system or (2) southward migration of the Mojave River between its present course and a more southerly route. Under the present topographic regime, a Death Valley Lake capable of overflowing the bedrock saddle at Ludlow, California and discharging southward into the Bristol, Cadiz, and Danby Lake basins (and eventually the Colorado River) would be over 12,000 km(2) in size. Few surface and subsurface indicators exist to support either a fluvial or lacustrine connection. Evidence from deep cores and boreholes drilled in Soda, Bristol, Cadiz, and Danby dry lake basins indicate that a hydrologic connection has not occurred during the past 4 myr. No well-documented paleoshoreline features have been located at elevations corresponding to the above hydrologic systems in Death Valley, Silver-Soda, Bristol, or Danby Lake basins. In the Cadiz, Silurian, and Broadwell basins these features have not been found at all. Therefore, we conclude that a hydrologic connection between the Death Valley-Owens River system and the Colorado River has not occurred along either of these routes since the middle Pliocene. (C) 1995 University of Washington.