Late Quaternary palaeowindflow of the Owens Lake region, California

Authors: Julie Laity*,
Topics: Geomorphology, Climatology and Meteorology, Arid Regions
Keywords: palaeowindflow, climate change, ventifacts, aeolian geomorphology, downslope winds
Session Type: Paper
Day: 4/10/2018
Start / End Time: 4:40 PM / 6:20 PM
Room: Napoleon B2, Sheraton 3rd Floor
Presentation File: No File Uploaded


The western Great Basin of the United States experienced major shifts in temperature, moisture, and circulation during climatic events that fluctuated from glacial to interglacial conditions. Late Pleistocene to mid-Holocene surface palaeocirculation for the Owens Lake region, east of the Sierra Nevada, California, was reconstructed by mapping groove orientations on ventifacts located near dated shorelines. Three principal wind flow directions – northwesterly (~315˚), southerly (~180˚), and southwesterly (~225˚) - were identified. Bidirectional northwesterly and southerly wind regimes (valley winds) have persisted from the late Pleistocene to the present. By contrast, southwesterly (downslope) winds are absent in today’s record, but were an important component of wind flow from the late Pleistocene to mid-Holocene. The results support the presence of a strong southern branch of the polar jet stream during the Last Glacial Maximum, as well as a southward shift in the tracks of Pacific winter storm track during millennial-scale cold intervals of the ensuing deglaciation. High velocity (>~30ms-1) downslope winds developed in association with a southwesterly storm track, with their development enhanced by cold, high-density air at the summit of the glaciated Sierra Nevada. Moisture-laden winds from 220 – 240˚ are approximately perpendicular to the range and associated with the greatest orographic enhancement of precipitation, the track of atmospheric rivers, and the highest wind velocities. The documented high velocity southwesterly flow across the region sheds light on the hydroclimatology of pluvial lakes, barrier beach development, wind erosion (both surface abrasion and dust entrainment), sand deposition, and seed and pollen transport.

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