Dynamics of Late Pleistocene Vertebrate Extinctions: Absolute Chronologies Based on AMS 14C Dating

在新大陆，至少有33个属的大型哺乳动物在距今11000年前灭绝，这为研究大陆规模灭绝的动力学提供了一个极好的机会。类似的大规模灭绝发生在整个新生代，并有助于确定生物地层陆地哺乳动物时代。由于灭绝发生在放射性碳测年的范围内，晚更新世事件可以用解决生态问题所需的精确度和准确度来确定。通过使用加速器质谱仪对单个化石进行14C测年，可以确定物种的年龄为+80年，距今11000年。拟议的研究将是对代表至少15个北美属的大型哺乳动物化石进行14C测年，这些化石在地理分布上发生了重大变化。测年将有助于确定：1)物种灭绝是否发生在10,800年后；2)如果属在几千年后灭绝，或集体灭绝超过几百年；3)晚更新世的生物变化是否发生在单个物种或整个动物群落的水平上。这项研究将是在多学科FAUNAP项目中提供时间控制的一个重要开端，该项目综合了北美晚更新世和全新世脊椎动物动物群的地理范围。

The extinction of at least 33 genera of large mammals ca 11,000 yr B.P. in the New World provides an excellent opportunity to study the dynamics of continental scale extinctions. Similar magnitude extinctions occurred throughout the Cenozoic and help define biostratigraphic Land Mammal Ages. Because the extinctions occurred within the range of radiocarbon dating, the Late Pleistocene events can be dated with the precision and accuracy needed to address ecological issues. By using accelerator mass spectrometry 14C dating of individual fossils, it is possible to date species to +80 years at 11,000 yr B.P. The proposed research will be the 14C dating of ~80-100 large mammal fossils representing at least 15 North American genera that have undergone major changes in geographic distribution. The dating will help establish 1) If extinctions occurred significantly after 10,800 yr B.P., 2) If genera went extinct over several millennia, or en masse over a few hundred years and 3) If Late Pleistocene biotic changes were at the level of individual species or entire animal communities. This research will be a major beginning for providing time control in the multidisciplinary FAUNMAP project, a synthesis of geographic ranges for Late Pleistocene and Holocene vertebrate faunas in North America.