A cosmic impact event at ∼12,800 Cal B.P. formed the Younger Dryas boundary (YDB) layer, containing peak abundances in multiple, high-temperature, impact-related proxies, including spherules, melt glass, and nanodiamonds. Bayesian statistical analyses of 354 dates from 23 sedimentary sequences over four continents established a modeled YDB age range of 12,835 Cal B.P. to 12,735 Cal B.P., supporting synchroneity of the YDB layer at high probability (95%). This range overlaps that of a platinum peak recorded in the Greenland Ice Sheet and of the onset of the Younger Dryas climate episode in six key records, suggesting a causal connection between the impact event and the Younger Dryas. Due to its rarity and distinctive characteristics, the YDB layer is proposed as a widespread correlation datum.
The Younger Dryas impact hypothesis posits that a cosmic impact across much of the Northern Hemisphere deposited the Younger Dryas boundary (YDB) layer, containing peak abundances in a variable assemblage of proxies, including magnetic and glassy impact-related spherules, high-temperature minerals and melt glass, nanodiamonds, carbon spherules, aciniform carbon, platinum, and osmium. Bayesian chronological modeling was applied to 354 dates from 23 stratigraphic sections in 12 countries on four continents to establish a modeled YDB age range for this event of 12,835–12,735 Cal B.P. at 95% probability. This range overlaps that of a peak in extraterrestrial platinum in the Greenland Ice Sheet and of the earliest age of the Younger Dryas climate episode in six proxy records, suggesting a causal connection between the YDB impact event and the Younger Dryas. Two statistical tests indicate that both modeled and unmodeled ages in the 30 records are consistent with synchronous deposition of the YDB layer within the limits of dating uncertainty (∼100 y). The widespread distribution of the YDB layer suggests that it may serve as a datum layer.
A TALE OF TWO CRATERS: CORIOLIS-AWARE TRAJECTORY ANALYSIS CORRELATES TWO PLEISTOCENE IMPACT STREWN FIELDS AND GIVES MICHIGAN A THUMB
Michael Davias, Stamford, CT and Thomas Harris, Lockheed-Martin (Retired), Orbit Operations, Valley Forge, PA
Pleistocene Epoch cosmic impacts have been implicated in the geomorphology of two enigmatic events. Remarkably, in both cases spirited debates remain unsettled after nearly 100 years of extensive research. Consensus opinion holds that the Australasian (AA) tektites are of terrestrial origin despite the failure to locate the putative crater, while a cosmic link to the Carolina bays is considered soundly falsified by the very same lack of a crater.
Likely >100 km in diameter, these impacts during geologically recent times should be readily detectable on the Earth’s surface. The improbability that two craters have eluded detection informs a hypothesis that a single impact at ~786 ka generated AA tektites as distal ejecta and Carolina bays as progeny of proximal ejecta. The AA astroblem search is focused on SE Asia despite a strewn field encompassing >30% of the Earth’s surface. This spatial scope implies to us that interhemispheric transits should be considered, as does findings that AA tektites were solidified in a vacuum, then ablated on re-entry at ~10 km sec-1. A Coriolis-aware triangulation network operating on the orientations of 44,000 Carolina bays indicates a focus near 43ºN, 84ºW. Referencing the work of Urey and Lin, we propose that a near-tangential strike to the Earth’s limb generated the 150 x 300 km oval depression that excises Saginaw Bay and opens Michigan’s Thumb. That region was likely buried under deep MIS 19 Laurentide ice at 786 ka. Schultz has shown that oblique impacts into continental ice sheets yield non-traditional astroblems, and multiple glaciations have since reworked this site, making identification more challenging. Hypervelocity gun tests show that oblique impacts produce a vertical plume of ejecta, biased slightly down-range. Ballistic trajectories reflecting such a plume deliver tektites to all AA finds when lofted at ~10 km sec-1 and parameterized with the proposed depression’s location and 222º azimuth. Chemical and isotopic characteristics of AA tektites suggest they were sourced from sandstone and greywacke of Mesozoic age, which is congruent with Michigan Basin strata lost when The Thumb developed. The distribution of proximal ejecta may explain anomalous pulses of regolith in moraines and sediment loading in regional drainage basins recently dated ~800 ka using 10Be/26Al methods.
The early evangelist Paul became a Christian because of a dazzling light on the road to Damascus, but one astronomer thinks it was an exploding meteor
NEARLY two thousand years ago, a man named Saul had an experience that changed his life, and possibly yours as well. According to Acts of the Apostles, the fifth book of the biblical New Testament, Saul was on the road to Damascus, Syria, when he saw a bright light in the sky, was blinded and heard the voice of Jesus. Changing his name to Paul, he became a major figure in the spread of Christianity.
William Hartmann, co-founder of the Planetary Science Institute in Tucson, Arizona, has a different explanation for what happened to Paul. He says the biblical descriptions of Paul’s experience closely match accounts of the fireball meteor seen above Chelyabinsk, Russia, in 2013.
Hartmann has detailed his argument in the journal Meteoritics & Planetary Science (doi.org/3vn). He analyses three accounts of Paul’s journey, thought to have taken place around AD 35. The first is a third-person description of the event, thought to be the work of one of Jesus’s disciples, Luke. The other two quote what Paul is said to have subsequently told others.
“Everything they are describing in those three accounts in the book of Acts are exactly the sequence you see with a fireball,” Hartmann says. “If that first-century document had been anything other than part of the Bible, that would have been a straightforward story.”
The Tusk has a large library of books related to catastrophism. I love them all. From the laboratory inspired to the ridiculously speculative, the range of publications touching on what happened 12,800 years ago is delightfully enormous. Unfortunately, many of these books have painfully small sales — sometimes in inverse proportion to their attention to the Younger Dryas Boundary event.
But that is changing this year. The world’s most popular alternative historian Graham Hancock has written “Magicians of the Gods.” By all accounts the book is an attentive study of the Tusk’s favorite planetary disaster and its consequences, and gives direct credit to the research of Kennett, West, Bunch and the gang for providing an empirical basis for many years of speculation and inference by others. A prolific author in the meantime, Hancock is presenting the new publication as a bookend to his enormously popular bestseller twenty years ago: Fingerprints of the Gods.
The YDB subject needs attention of all kinds in order to be widely appreciated and further researched. Thankfully, the science journal press has been (somewhat) busy for nearly a decade publishing point and counter-point to the YDB claims. And mainstream science reporters pay attention from time to time. But surprisingly, the popular and hyper-speculative “New Age” press has lagged behind, with scant attention paid to YDB data, despite support for many of their traditionally wild claims. You can find more about the YDB at Google Scholar or Academia.edu than the “Alternative” section of your local bookstore.
So, love him or scoff, Hancock is a welcome figure to the Tusk. He is a big deal and in our camp. Fingerprints of the Gods sold millions. His fans are everywhere and will soon be curious new experts in the Younger Dryas Boundary phenomena. Perhaps it is juvenile, but I enjoy the thought of the The Bos and his “Requiem” chorus cringing before the wave of attention this book will bring. Our subject is going precisely nowhere but up in the imagination of the public.
The Younger Dryas impact hypothesis suggests that multiple airbursts or extraterrestrial impacts occurring at the end of the Allerød interstadial resulted in the Younger Dryas cold period. So far, no reproducible, diagnostic evidence has, however, been reported. Quartz grains containing planar deformation features (known as shocked quartz grains), are considered a reliable indicator for the occurrence of an extraterrestrial impact when found in a geological setting. Although alleged shocked quartz grains have been reported at a possible Allerød-Younger Dryas boundary layer in Venezuela, the identification of shocked quartz in this layer is ambiguous. To test whether shocked quartz is indeed present in the proposed impact layer, we investigated the quartz fraction of multiple Allerød-Younger Dryas boundary layers from Europe and North America, where proposed impact markers have been reported. Grains were analyzed using a combination of light and electron microscopy techniques. All samples contained a variable amount of quartz grains with (sub)planar microstructures, often tectonic deformation lamellae. A total of one quartz grain containing planar deformation features was found in our samples. This shocked quartz grain comes from the Usselo palaeosol at Geldrop Aalsterhut, the Netherlands. Scanning electron microscopy cathodoluminescence imaging and transmission electron microscopy imaging, however, show that the planar deformation features in this grain are healed and thus likely to be older than the Allerød-Younger Dryas boundary. We suggest that this grain was possibly eroded from an older crater or distal ejecta layer and later redeposited in the European sandbelt. The single shocked quartz grain at this moment thus cannot be used to support the Younger Dryas impact hypothesis.