The Rambla highstand shoreline and the Holocene lake-level history of Tulare Lake, California, USA

Abstract

The stratigraphy associated with a highstand, wave-cut shoreline and with sites farther out into the lake plain constrain the Holocene lake-level history of Tulare Lake, California, USA as follows: Seven to eight major fluctuations in lake level occurred during the past 11,500 yr. Lake level was generally higher during the early Holocene (prior to ∼6000 cal yr BP) peaking in two highstands (65–70 masl) at 9500–8000 cal yr BP and 6900–5800 cal yr BP. Thereafter, it fluctuated at lower amplitude until reaching a major highstand during the most recent millennium between ∼750 and 150 cal yr BP. Two lake-level rises of lower amplitude were centered on 3300 and 1600 cal yr BP. At least three, probably brief, lowstands (<58 masl) occurred at: ∼9700, 5500, and soon after 3000 cal yr BP. None of the trenches studied penetrated materials as old as the Clovis era, suggesting that the prolific, near surface Clovis shoreline sites found at the southern margin of Tulare Lake are absent at the western margin. An archeological midden of middle to late Holocene age was found near the top of the highstand shoreline feature. This site was probably occupied for much of the Holocene after 5000 cal yr BP, a time interval during which the lake would have been much lower in elevation than that of the site and several hundreds of meters distant from the site.