Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilis and Mammuthus columbi), Channel Islands NationalPark, California, USA

Quaternary Research
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Abstract

Fossils of Columbian mammoths (Mammuthus columbi) and pygmy mammoths (Mammuthus exilis) have been reported from Channel Islands National Park, California. Most date to the last glacial period (Marine Isotope Stage [MIS] 2), but a tusk of M. exilis (or immature M. columbi) was found in the lowest marine terrace of Santa Rosa Island. Uranium-series dating of corals yielded ages from 83.8 ± 0.6 ka to 78.6 ± 0.5 ka, correlating the terrace with MIS 5.1, a time of relatively high sea level. Mammoths likely immigrated to the islands by swimming during the glacial periods MIS 6 (~ 150 ka) or MIS 8 (~ 250 ka), when sea level was low and the island–mainland distance was minimal, as during MIS 2. Earliest mammoth immigration to the islands likely occurred late enough in the Quaternary that uplift of the islands and the mainland decreased the swimming distance to a range that could be accomplished by mammoths. Results challenge the hypothesis that climate change, vegetation change, and decreased land area from sea-level rise were the causes of mammoth extinction at the Pleistocene/Holocene boundary on the Channel Islands. Pre-MIS 2 mammoth populations would have experienced similar or even more dramatic changes at the MIS 6/5.5 transition.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Late Quaternary sea-level history and the antiquity of mammoths (Mammuthus exilis and Mammuthus columbi), Channel Islands NationalPark, California, USA
Series title Quaternary Research
DOI 10.1016/j.yqres.2015.03.001
Volume 83
Issue 3
Year Published 2015
Language English
Publisher Elsevier
Contributing office(s) Geosciences and Environmental Change Science Center
Description 20 p.
First page 502
Last page 521
Country United States
State California
Other Geospatial Channel Islands National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N