200 ky paleoclimate record from Death Valley salt core

A 186-m-long core (DV93-1) from Death Valley, California, composed of inter bedded salts and muds contains a 200 k.y. record of closed-basin environmen ts and paleoclimates, interpreted on the basis of sedimentology, ostracodes , homogenization temperatures of fluid inclusions in halite, and correlatio n with shoreline tufa. The 200 k.y. paleoclimate record is dominated by two dry and/or warm and wet and cold cycles that occurred on a 100 k.y. time s cale. These cycles begin with mud-nat deposits (192 ka to bottom of core, a nd 60 ka to 120 ka). Wetter and/or colder conditions produced greater effec tive moisture; saline pan and shallow saline lake evaporites overlie mud-fl at sediments (186 ka to 192 ka and 35 ka to 60 ka), Eventually, enough,vate r entered Death Valley to sustain perennial lakes that had fluctuating wate r levels and salinities (120 ka to 186 ka and 10 ka to 35 ka). When more ar id conditions returned, mud-flat deposits accumulated on top of the perenni al lake sediments, completing the cycle (120 ka and 10 ka). Of particular s ignificance are the major lacustrine phases, 10 ka to 35 ka and 120 ka to 1 86 ka (oxygen isotope stages 2 and 5e-6), which represent markedly colder a nd wetter conditions than those of modern Death Valley. Of the two major la ke periods, the penultimate glacial lakes were deeper and far longer lastin g than those of the last glacial.