Chronological data doesn't support cosmic impact 12,800 ybp
Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago
David J. Meltzera,1, Vance T. Hollidayb, Michael D. Cannonc, and D. Shane Millerd
Significance
A key element underpinning the controversial hypothesis of a widely destructive extraterrestrial impact at the onset of the Younger Dryas is the claim that 29 sites across four continents yield impact indicators all dated to 12,800 ± 150 years ago. This claim can be rejected: only three of those sites are dated to this window of time. At the remainder, the supposed impact markers are undated or significantly older or younger than 12,800 years ago. Either there were many more impacts than supposed, including one as recently as 5 centuries ago, or, far more likely, these are not extraterrestrial impact markers.
Abstract
According to the Younger Dryas Impact Hypothesis (YDIH), ∼12,800 calendar years before present, North America experienced an extraterrestrial impact that triggered the Younger Dryas and devastated human populations and biotic communities on this continent and elsewhere. This supposed event is reportedly marked by multiple impact indicators, but critics have challenged this evidence, and considerable controversy now surrounds the YDIH. Proponents of the YDIH state that a key test of the hypothesis is whether those indicators are isochronous and securely dated to the Younger Dryas onset. They are not. We have examined the age basis of the supposed Younger Dryas boundary layer at the 29 sites and regions in North and South America, Europe, and the Middle East in which proponents report its occurrence. Several of the sites lack any age control, others have radiometric ages that are chronologically irrelevant, nearly a dozen have ages inferred by statistically and chronologically flawed age–depth interpolations, and in several the ages directly on the supposed impact layer are older or younger than ∼12,800 calendar years ago. Only 3 of the 29 sites fall within the temporal window of the YD onset as defined by YDIH proponents. The YDIH fails the critical chronological test of an isochronous event at the YD onset, which, coupled with the many published concerns about the extraterrestrial origin of the purported impact markers, renders the YDIH unsupported. There is no reason or compelling evidence to accept the claim that a cosmic impact occurred ∼12,800 y ago and caused the Younger Dryas.
Re: Chronological data doesn't support cosmic impact 12,800
This 11,000 BC time frame has many circumstantial observations that do favor the theory oi an earth shaking cataclysm around that date. In his book "Atlantis: the Antediluvian World," Gramercy, NY 1949 ed. p.27, Ignatius Donnelly, adapting data from j. Opperts' "Chronologia Biblique fixee par les Inscriptions Cuneiformes" Paris 1868, compared the Egyptian zodiacal calendar with the cyclical lunar calendar of the Assyrians. Donnelly arrived at the date for coincidence of the two calendars as 11,542 BC.
A number of animal extinctions occurred in this general time frame (11,000 BC to 10,000 BC): the giant bison, the new world horse, the sabre toothed tiger, the mammoth, the North American sloth, and the North American camel.
11,000 BC is also the time frame for the appearance of Clovis Man. (A world wide catastrophe would be a likely stimulus for migrations of large population groups to new areas.)
Immanuel Velikovsky's book "Worlds in Collision" 1950 was discredited by scholars at the time in part because his chronology for a world cataclysm, caused by Earth's close brush with cometary (future planetary) Venus, was shown to be wrong, because ancient astronomical charts show Venus in its present orbit at an earlier time than the date of 1500 BC that Velikovsky's book had assigned to the cataclysm. Velikovsky had amassed a very vast number of ancient accounts of an apparent world-wide catastrophe within the memory of man. Was the actual time frame around 11,000 BC?
