Erwin, Diane M. , Schorn, Howard E. .
Tufa-encrusted plants from Late Pleistocene Searles Lake, California, USA.
California’s Searles Lake (dry) is a former Pleistocene lake bound by the Argus Range to the west, the Slate Range to the east. The local flora is characterized by desert-scrub with Creosote bush (Larrea) dominating lower elevations. Discovered within a small paleoembayment along the western shore of Searles Lake near the Point of Rocks (POR) area are remnants of woody plants encrusted with a rind of tufa, 2.0-17.0 cm thick. Stem imprints occur at 17 sites with most sites located within a 125 m (410 ft.) stretch along the 622 m (2040 ft.) elevation contour. Specimens are 1.0 – 30.0 cm wide, showing long, narrow, parallel ridges and shallow grooves that run in a lengthwise pattern similar to the strip-like bark of Juniperus (juniper). Wood is also juniper-like showing short, narrow, uniseriate rays 1-9 cells high, the majority have five cells or less and lack horizontal resin ducts. Of the two junipers growing in the region today, the tufa imprints most likely were made by J. osteosperma (Utah juniper), which grows on Argus Peak at 1402 m (4600 ft.) northwest of and roughly five miles upslope from the fossil sites. Other nearby Utah juniper populations occur on Maturango Peak about 23 km (14 mi.) northeast of the POR embayment and to the east in the Panamint Range, but are at elevations of 610 to 2073 m (2000 - 6800 ft.) higher than the fossil sites. Study is underway to determine if the tufa imprints at the 622 m contour sites are in situ. Evenness in the thickness of encasing tufa around many stems suggests some were upright partially or fully submerged near shore at a time when the basin was filled with water and under climatic conditions that exist during major glacial (pluvial) episodes as occurred during the late Pleistocene.
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1 - University of California, Museum of Paleontology, 1101 Valley Life Sciences Building, Berkeley, CA, 94720, USA
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM