Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ∼12,800 Years Ago: A Reply.

Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ~12,800 Years Ago: A Reply Most of the following discussion deals with the implications of the Younger Dryas Boundary (YDB) layer, including evidence supporting extensive YDB burning and its proposed age, identification, and context within the chronological record. It is important to note that the actual radiocarbon date ( HT $\mathrm{10,900}\pm 100$ ht SP 14 sp C y BP) for the YDB impact event has remained the same in all YDB publications, whereas the calibrated age has been revised multiple times by an independent, international body. Even so, the stratigraphic context of a proxy-rich layer or samples at these sites I supports a YDB age i " (p. E4351; emphasis added) and later, they wrote that "because these nine sites contain the same abundance peaks in proxies that are found at well-dated YDB sites, we have I proposed i that they are of YDB age" (app., p. 34; emphasis added). Here is the inferred sequence of events: (1) ~12,800 y ago, Clovis artisans at Topper were producing chert projectile points just before the YDB impact event occurred, as shown by the lack of YDB spherules beneath the debitage; (2) then, the YDB impact event occurred, as shown by spherules directly atop the debitage; (3) a multicentury hiatus in quarry usage followed, after which post-Clovis Paleoindians resumed quarry activity after the middle of the Younger Dryas. [Extracted from the article]
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