Problematic dating of claimed Younger Dryas boundary impact proxies
نویسندگان
چکیده
منابع مشابه
Cosmic impact or natural fires at the Allerod-Younger Dryas boundary: a matter of dating and calibration.
Wittke et al. (1) present evidence of a major cosmic impact at the onset of the Younger Dryas (YD) episode, including some markers found in the top of the well-known Usselo marker horizon (UH). This finding is contrary to our extensive radiocarbon dating effort from this horizon (2), which shows that the UH at Aalsterhut postdates the onset of the YD. Furthermore, Wittke et al. (1) misinterpret...
متن کاملInconsistent impact hypotheses for the Younger Dryas.
Israde-Alcántara et al. (1) presented evidence from Lake Cuitzeo sediments and argued that it supports the Younger Dryas (YD) impact hypothesis of Firestone et al. (2) for a major extraterrestrial impact event “involving multiple airburst(s) and/or ground impact(s) at 12.9 ka.” Firestone et al. (2) did not specify the details of the impact but proposed that it had “continentwide effects” and wa...
متن کاملReply to van Hoesel et al.: Impact-related Younger Dryas boundary nanodiamonds from The Netherlands.
Van Hoesel et al. (1) refer to nanodiamonds at the top of the Usselo horizon at Aalsterhut, The Netherlands, having an average age of 10.845 ± 0.015 C ka (12.70 ± 0.06 cal ka) (1); they found no nanodiamonds outside hat layer. Earlier, nanodiamonds were reported at the top of theUsselo in Lommel, Belgium,∼30 km southwest of Aalsterhut, acknowledged as the Younger Dryas boundary layer (YDB) [Tia...
متن کاملA Blind Test of the Younger Dryas Impact Hypothesis
The Younger Dryas Impact Hypothesis (YDIH) states that North America was devastated by some sort of extraterrestrial event ~12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB), i.e., ~12.8k cal yrs BP? A test rep...
متن کاملGeochemical proxies of North American freshwater routing during the Younger Dryas cold event.
The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from approximately 12.9 to 11.5 kiloyears B.P. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulatio...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2015
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.1518945112