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In response to
"Tonight is our lecture on the study that said man was in SoCal 150,000 years ago. I'm not yet sure what side our presenter is on."
by
Meg
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He's a paleontologist so we'll see :/
Posted by
Meg (aka Mojave)
Apr 8 '21, 18:02
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The talk will focus on the Cerutti Mastodon (CM) site, which yielded remains of a single American mastodon (Mammut americanum) associated with evidence indicating hominins used stone hammers and anvils to break limb bones and molars 130.7 ± 9.4 ka during the MIS 6 to 5 transition. Taphonomic evidence for human agency will be presented and includes bone impact features (cone flakes, bulbs of percussion, and an arcuate impact notch); stone impact and usewear features (negative flake scars, Hertzian initiations, and angular fractures); bone, tusk, and stone distribution patterns (femoral diaphysis fragments clustered around a single large cobble, detached femoral heads positioned side-by-side, and a vertically oriented tusk); differential bone breakage (intact fragile ribs vs. fragmented limb bones); and bone, molar, and stone refits (80 cm displacement of pieces of a partial femoral diaphysis, 3-m displacement of pieces of a single molar, 3-m displacement of pieces of a single large cobble). Significantly, most CM bones and stones were enclosed within crusts of pedogenic carbonate that establish a “chain of evidence” showing that breakage and positioning of objects at the site occurred many thousands of years ago before burial of the site. No knapped stones or cut-marked bones were recovered at the CM site, which is hypothesized to represent a bone-processing site occupied for a short period of time for a limited set of activities (expedient stone hammers and anvils used to break mastodon bones for marrow extraction and/or production of raw materials). Reaction to the hypothesis for human agency also will be discussed, as well as the results of a recent follow-up study documenting the presence of bone residues on CM cobble hammerstones and anvils.
Dr. Thomas Deméré is Curator of Paleontology and Director of PaleoServices at the San Diego Natural History Museum located in San Diego’s historic Balboa Park. He received his BS in Geology from San Diego State University, his MS in geological sciences from the University of Southern California, and his Ph.D. in evolutionary biology from the University of California, Los Angeles. Dr. Deméré has worked at the Museum since 1979, where he oversees paleontological research and collection activities, as well as the paleontological mitigation program. His research broadly involves documenting the Cenozoic biological and geological history of the southern California region, with special focus on the evolutionary history and comparative anatomy of marine mammals and the regional Plio-Pleistocene record of marine and terrestrial biotas and paleoenvironments.
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