Pergamon Quaterml 0 (;e<J('hron<d(Jgy (Qmm>rnarv S<icme f~,elic.~). \ol. 13, pp 417-422. 19'44 ('op~,righi ~) 10{;4 El',c~lcl Science Lid. Printed m (;real Britain. All right~ rcscr~ect ()277-37tJl/n4 $2(~.11(~ 0277-3791 (94) E 0033-7 LUMINESCENCE DATING OF LATE QUATERNARY AEOLIAN DEPOSITS AT DALE LAKE AND CRONESE MOUNTAINS, MOJAVE DESERT, CALIFORNIA H.M. Rendell,* N. Lancaster and V.P. Tchakerian$ *Geography Laboratory, University of Sussex, Falmer, Brighton BN1 9QN, U.K. .Quaterna O, Sciences Center, Desert Research Institute, P.O. Box 60220, Rend, NV 89500, U.S.A. SDepartment of Geography, Texas A&M University, College Station, TX 77843, U.S.A. Relict aeolian deposits and landforms that can provide important information on the timing, geographical extent and intensity of periods of aeolian sand accumulation are widespread in the Mojave Desert, California. The Pleistocene part of the record is mostly undated. The stratigraphy and sedimentology of sites near Dale Lake (Dale Lake sand ramp) and the Cronese Mountains (Cat Dune) were studied, and luminescence dating techniques used to try to establish a chronological framework for the deposits. The dating of these sites proved difficult, with major disparities between the results of quartz and feldspar thermoluminescence (TL) dating, particularly where the sediments comprised a mixture of aeolian and colluvial material. However, initial results. based on quartz TL and feldspar infra-red stimulated luminescence dating, indicate the existence of two main periods of Late Pleistocene aeolian deposition between >35 to 25 ka and 15 to 10 ka. INTRODUCTION Aeolian deposits are widespread in the Mojave Desert and occur in relation to well-defined regional and local-scale sand transport corridors that extend from source areas in the western and central Mojave to depositional sinks to the east and the south (Smith, 1984; Zimbelman and Williams, 1990). Areas of relict dunes and sand sheets that are stabilized by vegetation, talus deposits and soil development, as well as ventifacts that are covered by desert varnish, indicate a long history of episodic transport along these pathways (e.g. Smith, 1967; Laity, 1992: Tchakerian, 1992), but the chronology of these events is poorly known. SAND RAMP GEOMORPHOLOGY AND STRATIGRAPHY Sand ramps are topographically controlled accu- mulations that represent the amalgamation of deposits of aeolian sand, talus derived from adjacent mountain slopes and fluvial and colluvial sediments. Most sand ramps in the Mojavc Desert are situated on the western piedmont slopes of mountain ranges and accumulated as sand was blown up against the mountain front by the prevailing westerly winds. They range in thickness from 5 m to as much as 70 m. Variations in sand ramp volume probably reflect the size of the sand source region. To test the application of luminescence dating x ,a. ram0,tu,,s,e, MO AVE '. I- /o.Eoo, - E.~-~ dry lakes E ~ W ,~" ~ ".. I ~ l - / ..... t ~ [ ~ = = interstatehighway Ci°n. ese ~ ~ ~ ~'.,. I ~ taKes , Baker x" '~t l ~yZ .... state boundary ~ \,~ /"} ,¢"e ~" r~ r "4 =~ SaltLake {~,~. ~ .... ~-, ...... l= 0~/ NEVADA Sa Cat Dune ~J~2:l a°°a LaKe I San '~'/"~o.~ ,.. L UTAH ,,.~. ~1 ~-:.Z'Uf~'-Y Kelso I F~ %.\~=l------ v" . . Manix -' l Dunes I \ '< u a r . ~ Basin Palaeolake ~ l / ARIZONA • ~,.-." I/ ~ ~ i si,,~,~,~_ ~to~x f I t ii Io~4~ \~ t /, c~ ~" ~ .BristotLake L' , <..-~:..x Cadiz Lake ) ~ ~'~'.~:..,. Oanby Lake .i Z~ DaleLake ~:~": i../" i ~ardino Twentynine = Palms • ~ " X t Palm Springs Dale Lake Sand Ramp / \o km 30 i i I FIG. 1. East-central Mojave Desert. showing location of the sand ramps investigated. 417