147 Recent Advances in Archaeological Geology (Posters)

Monday, 26 September 2016
9:00 AM - 6:30 PM
Exhibit Hall E/F

THE LATE PLEISTOCENE TO HOLOCENE ARCHAEOLOGY AND LAKE LEVELS OF PLUVIAL LAKE WARNER, OREGON

Paper number: 147-24
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

When Paleoindians moved into the northern Great Basin, they occupied the shores of pluvial Lake Warner located near the intersection of Oregon, California, and Nevada. The types of resources available to this basin’s initial inhabitants depended on the lake’s changing bathymetry, with marsh expanding or contracting around quiet open water. To better understand when these people first arrived and their adaptation as the lake receded, we reconstructed pluvial Lake Warner’s lake levels from the Late Pleistocene to Holocene using diagnostic artifact type distribution, radiocarbon dating of shoreline features, and tephrochronology.

What we found is that pluvial Lake Warner reached its highstand ca. 16,000 cal BP (post-LGM) and quickly receded during the latest Pleistocene. People arrived carrying fluted (i.e., Western Clovis) and Western Stemmed points before 12,000 cal BP, after the lake had lost over half of its previous volume. As the lake continued to decline, people using Western Stemmed points followed its regression, reaching the broad valley floor below around 9650 cal BP, when the fine-grained silts and sands blown from the dry playa began accumulating in the floors of nearby rockshelters. By the time Mazama tephra fell ca. 7600 cal BP, pluvial Lake Warner had withdrawn to the modern level of Warner Lakes. The valley floor developed dune-and-slough topography in response to the repeated wetting-and-drying episodes during the middle Holocene, and by 5500 cal BP these dunes separated the once large lake into a series of small remnants. These lakeshores continued to draw people to their abundant resources of endemic fish and marsh plants into the historic period, despite occasional inundation, which included a weak transgression during the late Holocene.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-287174

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