Directly dated MIS 3 Lake-Level Record from Lake Manix, Mojave Desert, California, USA

Abstract

An outcrop-based lake-level curve, constrained by ~ 70 calibrated 14C ages on Anodonta shells, indicates at least 8 highstands between 45 and 25 cal ka BP within 10 m of the 543-m upper threshold of Lake Manix in the Mojave Desert of southern California. Correlations of Manix highstands with ice, marine, and speleothem records suggest that at least the youngest three highstands coincide with Dansgaard–Oeschger (D–O) stadials and Heinrich events 3 and 4. The lake-level record is consistent with results from speleothem studies in the Southwest that indicate cool wet conditions during D–O stadials. Notably, highstands between 43 and 25 ka apparently occurred at times of generally low levels of pluvial lakes farther north as interpreted from core-based proxies. Mojave lakes may have been supported by tropical moisture sources during oxygen-isotope stage 3, perhaps controlled by southerly deflection of Pacific storm tracks due to weakening of the sea-surface temperature gradient in response to North Atlantic climate perturbations.

A late Wisconsin (32–10k cal a BP) history of pluvials, droughts and vegetation in the Pacific south‐west United States (Lake Elsinore, CA)

“…(G) Lake Manix altitude redrawn from Reheis et al . (). P5–8 represent Lake Manix highstands from Reheis et al .…”

“…As a result, the aquatic fauna‐based carbon dates used by Reheis et al . () for the glacial are probably different than reported due to an unknown glacial reservoir effect. Together, these two site age limitations provide some flexibility in the correlation between the two sites.…”

“…However, Reheis et al . () use a standard reservoir correction of 140 years as determined by Owen et al . () and Miller et al .…”

Environmental history recorded in aeolian deposits under stone pavements, Mojave Desert, USA

“…One way or the other, the bimodal clast alignment pattern argues for some rearrangement of the rock fragments by lateral processes (Dietze et al, 2013). The OSL age of 50.9 ± 4.1 ka within unit S I implies that formation of this unit started prior to Afton Canyon incision (25 cal ka BP) but overspill discharge of the Mojave River into the Soda basin during OIS 4/6 (Reheis and Redwine, 2008;Reheis et al, 2015) is a plausible source of aeolian material. The timing of the onset of this aeolian accretion period remains unresolved.…”

“…We infer that the onset of Lake Mojave I is approximately recorded by the OSL sample at 33 cm depth (25.9 ± 2.0 ka). Thus, the lower 20 cm of this unit were accumulated before Lake Mojave formed but when the Mojave River already delivered water to the Soda basin (several highstands between 42 cal ka BP and 25 cal ka BP; Reheis and Redwine (2008); Reheis et al (2015)). A slightly younger aeolian activity onset was noticed by Lancaster and Tchakerian (2003), who describe a sand ramp at Hanks Mountain, near Silver Lake Playa (Figure 1) with a maximum IRSL deposition age of 34.7 ka.…”