Allen West

Allen West
Comet Research Group

Ph.D.

About

91
Publications
57,959
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,153
Citations

Publications

Publications (91)
Article
Full-text available
We present evidence that in ~ 1650 BCE (~ 3600 years ago), a cosmic airburst destroyed Tall el-Hammam, a Middle-Bronze-Age city in the southern Jordan Valley northeast of the Dead Sea. The proposed airburst was larger than the 1908 explosion over Tunguska, Russia, where a ~ 50-m-wide bolide detonated with ~ 1000× more energy than the Hiroshima atom...
Article
Full-text available
At Abu Hureyra (AH), Syria, the 12,800-year-old Younger Dryas boundary layer (YDB) contains peak abundances in meltglass, nanodiamonds, microspherules, and charcoal. AH meltglass comprises 1.6 wt.% of bulk sediment, and crossed polarizers indicate that the meltglass is isotropic. High YDB concentrations of iridium, platinum, nickel, and cobalt sugg...
Article
Full-text available
A multi-proxy study of changing environmental conditions in a Younger Dryas sequence in southwestern Manitoba, Canada: Response to comments by Breslawski et al., Quaternary Research Volume 94, 210–211 - Volume 94 - Allen West, James Kennett, James Teller, Matthew Boyd
Chapter
The Younger Dryas (YD) impact hypothesis proposes that fragments of a large, disintegrating asteroid/comet struck the Earth ∼12,800 years ago. This event simultaneously deposited high concentrations of platinum, high-temperature spherules, melt glass and nanodiamonds into the YD boundary layer (YDB) at >50 sites worldwide. Here, we report on a ∼12,...
Article
Full-text available
A widespread platinum (Pt) anomaly was recently documented in Greenland ice and 11 North American sedimentary sequences at the onset of the Younger Dryas (YD) event (~12,800 cal yr BP), consistent with the YD Impact Hypothesis. We report high-resolution analyses of a 1-meter section of a lake core from White Pond, South Carolina, USA. After develop...
Article
Multi-proxy analyses of a sequence spanning the Younger Dryas (YD) in the Glacial Lake Hind basin of Manitoba provides insight into regional paleohydrology and paleovegetation of meltwater rivers and lakes spanning >4000 yr; the sequence is controlled by 25 new accelerator mass spectrometry ages. This lake, dammed by the Laurentide Ice Sheet, overf...
Data
Raw data and references for Table S7 in Moore et al. (2017) Widespread platinum anomaly documented at the Younger Dryas onset in North American sedimentary sequences. Scientific Reports, Sci Rep., 44031. doi: 10.1038/srep44031 Table compares Pt, Pd, Pt/Pd concentrations at Younger Dryas Boundary to values for Impactites (65 Ma, 145 Ma, 2.55 Ga), M...
Article
Full-text available
The Younger Dryas (YD) impact hypothesis posits that fragments of a large, disintegrating asteroid/comet struck North America, South America, Europe, and western Asia ~12,800 years ago. Multiple airbursts/impacts produced the YD boundary layer (YDB), depositing peak concentrations of platinum, high-temperature spherules, meltglass, and nanodiamonds...
Conference Paper
Full-text available
This paper overviews the multiple lines of evidence that collectively suggest a Tunguska-like, cosmic airburst event that obliterated civilization-including the Middle Bronze Age (MBA) city-state anchored by Tall el-Hammam-in the Middle Ghor (the 25 km diameter circular plain immediately north of the Dead Sea) ca. 1700 BCE, or 3700 years before pre...
Article
Full-text available
Although much has been written about a cosmic impact event in the Western Alps of the Mt. Viso area, the event closely tied with the Younger Dryas Boundary (YDB) of 12.8 ka and onset of the Younger Dryas (YD), the affected land surface is considered to contain a similar black mat suite of sediment found on three continents. While work elsewhere has...
Chapter
The Younger Dryas cooling episode came about in the Northern Hemisphere in an abrupt manner atypical of deglaciation events. This cooling resulted in the Pleistocene extinctions of many genera of faunas and coincided with the disappearance of the Clovis culture. The Younger Dryas Cosmic Impact of 12.8 kya is then considered as a hypothesis that exp...
Chapter
Chapter 8 reviews the evidence for a suspected cosmic impact over North America at the onset of the Younger Dryas climatic period with the near simultaneous extinction of classic Pleistocene megafauna and the Clovis technoculture. The impact related proxies that are used to detect the impact layer, such as spherules, silica-rich glass, nanodiamonds...
Article
Full-text available
Controversy over the alpine route taken by the Hannibalic Army from the Rhône Basin into Italia in 218 bc (2168 cal bp) has raged amongst classicists for over two millennia. Because Hannibal crossed the Alps, the significance for identifying the route taken by the Punic Army lies more in its potential for identifying sites of historical archaeologi...
Article
Full-text available
The Younger Dryas boundary (YDB) cosmic-impact hypothesis is based on considerable evidence that Earth collided with fragments of a disintegrating ≥100-km-diameter comet, the remnants of which persist within the inner solar system ∼12,800 y later. Evidence suggests that the YDB cosmic impact triggered an “impact winter” and the subsequent Younger D...
Article
Full-text available
Part 1 of this study investigated evidence of biomass burning in global ice records, and here we continue to test the hypothesis that an impact event at the Younger Dryas boundary (YDB) caused an anomalously intense episode of biomass burning at ∼12.8 ka on a multicontinental scale (North and South America, Europe, and Asia). Quantitative analyses...
Article
Full-text available
The Younger Dryas interval (YD) was a period of widespread, abrupt climate change that occurred between 12,900 and 11,700 cal yr BP (10,900–10,000 ¹⁴C BP). Many sites in the Northern Hemisphere preserve a sedimentary record across the onset of the YD interval, including sites investigated in sedimentary basins located in central Mexico (Chapala, Cu...
Article
Full-text available
Download paper at: http://rdcu.be/zYNl ..... Large quantities of impact-related microspherules have been found in fine-grained sediments retained within seven out of nine, radiocarbon-dated, Late Pleistocene mammoth (Mammuthus primigenius) and bison (Bison priscus) skull fragments. The well-preserved fossils were recovered from frozen “muck” deposi...
Article
Full-text available
Previously, a large platinum (Pt) anomaly was reported in the Greenland ice sheet at the Younger Dryas boundary (YDB) (12,800 Cal B.P.). In order to evaluate its geographic extent, fire-assay and inductively coupled plasma mass spectrometry (FA and ICP-MS) elemental analyses were performed on 11 widely separated archaeological bulk sedimentary sequ...
Article
Full-text available
Previous evidence for fragments of a cosmic airburst in the Western Alps has been shown to reside in weathering rinds in surface clasts of Late Glacial (LG) (mid-LG-post Allerød) deposits and in Ah horizons of several associated paleosols. In contrast to outlying strata, Younger Dryas (YD) paleosol horizons contain minor reworked airburst evidence...
Article
Full-text available
The enigma of Hannibal’s route across the Alps in 218 BC is one of the most enduring questions of antiquity. Many authorities, some of whom have never ventured into the mountains, have argued for various preferred crossings of the Alps. Earlier efforts to identify the route focused on the two-tier rockfall and regrouping area on the lee side of the...
Article
Full-text available
As discussed in Part I, a large accumulation of mammalian faeces at the mire site in the upper Guil Valley near Mt. Viso, dated to 2168 cal 14C yr., provides the first evidence of the passage of substantial but indeterminate numbers of mammals within the time frame of the Punic invasion of Italia. Specialized organic biomarkers bound up in a highly...
Article
Full-text available
Controversy over the alpine route that Hannibal of Carthage followed from the Rhône Basin into Italia has raged amongst classicists and ancient historians for over two millennia. The motivation for identifying the route taken by the Punic Army through the Alps lies in its potential for identifying sites of historical archaeological significance and...
Article
Full-text available
Understanding the mechanism associated with rates of weathering and evolution of rocks→sediment→soil→paleosol in alpine environments raises questions related to the impact of microbial mediation versus various diverse abiotic chemical/physical processes, even including the overall effect of cosmic impact/airburst during the early stage of weatherin...
Article
Full-text available
Controversy over the alpine route that Hannibal of Carthage followed from the Rhône Basin into Italia has raged amongst classicists and ancient historians for over two millennia. The motivation for identifying the route taken by the Punic Army through the Alps lies in its potential for identifying sites of historical archaeological significance and...
Conference Paper
Full-text available
The presence of a dark stratal layer, known as Younger Dryas black mat, has been reported globally at many different sites. Samples of this black mat have been carbon dated to approximately 12,800 years BP, which coincides with the Younger Dryas Stadial, a period of extensive cooling. One hypothesis for the presence of the black mat layer is that a...
Article
Full-text available
Holliday (1) rejects age-depth models for the Younger Dryas boundary layer (YDB) in Kennett et al. (2), claiming that they are incorrect for several reasons, including age reversals, high age uncertainties, and use of optically stimulated luminescence (OSL) dating. These same claims previously were presented in Meltzer et al. (3) and were discussed...
Article
Full-text available
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, aci...
Conference Paper
Full-text available
A sediment column (0-110 cm) from Squires Ridge (38ED365), a stratified archaeological site on the Tar River in North Carolina, was analyzed to evaluate magnetic microspherules and other geochemical markers reported for the Younger Dryas Boundary (YDB). Here we report on microspherules using a Scanning Electron Microscope (SEM) and Energy Dispersiv...
Article
Full-text available
A major cosmic-impact event has been proposed at the onset of the Younger Dryas (YD) cooling episode at ≈12,800 ± 150 years before present, forming the YD Boundary (YDB) layer, distributed over >50 million km2 on four continents. In 24 dated stratigraphic sections in 10 countries of the Northern Hemisphere, the YDB layer contains a clearly defined...
Article
Full-text available
Recent analyses of sediment samples from “black mat” sites in South America and Europe support previous interpretations of an ET impact event that reversed the Late Glacial demise of LGM ice during the Bølling Allerød warming, resulting in a resurgence of ice termed the Younger Dryas (YD) cooling episode. The breakup or impact of a cosmic vehicle a...
Article
Full-text available
Boslough et al. (1) offer no alternate explanation for ∼10 million tonnes of Younger Dryas spherules recovered from 18 sites across ∼50 million square kilometers of North America, Europe, and the Middle East (2). In addition, the authors claim that our hypothesis “demonstrates a misunderstanding of comets.” However, the misunderstanding is theirs a...
Article
Full-text available
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 14C ka (12.70 ± 0.06 cal ka) (1); they found no nanodiamonds outside hat layer. Earlier, nanodiamonds were reported at the top of the Usselo in Lommel, Belgium, ∼30 km southwest of Aalsterhut, acknowle...
Article
Full-text available
Ives and Froese (1) challenge the identification of the Chobot black mat layer at the Younger Dryas (YD) boundary (YDB), claiming that no black mats have been documented in western Canada (2). To the contrary, Haynes, a lead investigator of YD-age black mats, mapped two YD-age mat sites in western Canada (figure 1 in ref. 3): one ∼200 km south of t...
Article
Full-text available
Weathering rinds have been used for decades as relative age indicators to differentiate glacial deposits in long Quaternary sequences, but only recently has it been shown that rinds contain long and extensive palaeoenvironmental records that often extend far beyond mere repositories of chemical weathering on both Earth and Mars. When compared with...
Article
Full-text available
Previous work has ascribed a cosmic impact origin to black, high-temperature, carbon-encrusted beds (2–3 cm thick), associated with the Younger Dryas readvance of ice at 12.8 ka during the Late Glacial in the northern Andes of Venezuela. The evidence for this includes carbon spherules, aluminosilicate melt rocks, melted coatings of glass-like amorp...
Article
Full-text available
Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently co...
Article
Full-text available
Iturralde may have formed under natural circumstances unrelated to an impact. However, there is the presence of millions of clusters of glass beads in sediment.
Article
Full-text available
No excess magnetization of the Younger Dryas microspheres refutes the hypothesis that these microspheres could have formed during lightning discharges.
Article
A diverse assemblage of nanodiamonds found in the Younger Dryas boundary layer (YDB) across North America is consistent with a high-temperature cosmic event at 12.9 ka. Abundance peaks in biomass-burning proxies, such as charcoal, grape-cluster soot, carbon spherules, and glass-like carbon suggest that a major, cross-continental episode of biomass-...
Article
Full-text available
Blaauw et al. (1) take issue with our age–depth model for the Cuitzeo core. They state that no offset for our accelerator mass spectrometry (AMS) 14C dates was quantified, that our identification of the Cieneguillas tephra is doubtful, that we used an outdated calibration model, and they object to our rejection of six AMS dates in the anomalous zon...
Article
Full-text available
It has been proposed that fragments of an asteroid or comet impacted Earth, deposited silica- and iron-rich microspherules and other proxies across several continents, and triggered the Younger Dryas cooling episode 12,900 years ago. Although many independent groups have confirmed the impact evidence, the hypothesis remains controversial because so...
Article
Full-text available
We report the discovery in Lake Cuitzeo in central Mexico of a black, carbon-rich, lacustrine layer, containing nanodiamonds, microspherules, and other unusual materials that date to the early Younger Dryas and are interpreted to result from an extraterrestrial impact. These proxies were found in a 27-m-long core as part of an interdisciplinary eff...
Article
Full-text available
Three approaches are used to test whether or not human populations across North America were affected by abrupt climate change and/or other environmental factors associated with the onset of the Younger Dryas (YD) cooling episode at ca. 12,900 cal BP. They are: (1) frequency analyses of Paleoindian projectile points from across North America; (2) t...
Article
Full-text available
We report the discovery in the Greenland ice sheet of a discrete layer of free nanodiamonds (NDs) in very high abundances, implying most likely either an unprecedented influx of extraterrestrial (ET) material or a cosmic impact event that occurred after the last glacial episode. From that layer, we extracted n-diamonds and hexagonal diamonds (lonsd...
Conference Paper
Full-text available
Research into the proposed Younger Dryas impact event (1) revealed that across North America and NW Europe, 12,900-year-old sediments contain nanodiamonds at >1 billion cm-1 and ranging in size from 1 to 1700 nm (2). They appear in bulk sediment but mostly occur inside carbon spherules and glass-like carbon, which appear to be the charred, amorphou...