Quantifying the distribution of nanodiamonds in pre-Younger Dryas to recent age deposits along Bull Creek, Oklahoma Panhandle, USA

Abstract

Significance In 2007, scientists proposed that the start of the Younger Dryas (YD) chronozone (10,900 radiocarbon years ago) and late Pleistocene extinctions resulted from the explosion of a comet in the earth’s atmosphere. The ET event, as it is known, is purportedly marked by high levels of various materials, including nanodiamonds. Nanodiamonds had previously been reported from the Bull Creek, Oklahoma, area. We investigate this claim here by quantifying the distribution of nanodiamonds in sediments of different periods within the Bull Creek valley. We found high levels of nanodiamonds in YD boundary deposits, supporting the previous claim. A second spike in nanodiamonds during the late Holocene suggests that the distribution of nanodiamonds is not unique to the YD.

Did Nanodiamonds Rain from the Sky as Woolly Mammoths Fell in their Tracks Across North America 12,900 Years Ago?

“…Thus, the mere presence of nano/microdiamonds in sediments is not an indicator of impact processes. However, nanodiamonds concentrated at the YDB (and their complete absence immediately above and below this level), as reported [3][4][5][6][7][8], would suggest a unique event occurred at the time the sediments were deposited. In regard to the nature of the event, much emphasis has been placed on the reported presence of lonsdaleite in YDB sediments because it has been traditionally associated with shock processing [4][5][6][7].…”

“…[3]. Later, Bement et al [8] reported a three order-of-magnitude larger 190 p.p.m. spike of nanodiamonds at the Bull Creek YDB, which is higher than that reported at all other YDB sites studied [7].…”

“…While there are no known impact structures in North America that date to the onset of the YD stadial, physical evidence of one or more impact/bolide events is argued present in a stratigraphic horizon that is inferred to date to the Bølling-Ållerod/YD boundary (YDB) and span several continents (North America, South America, Greenland Ice Sheet, Europe, and the Middle East). While many of the proposed impact markers have been abandoned or rejected [1], reports of elevated concentrations of nanometer-sized diamonds, in particular the rare 2H polytype of diamond, lonsdaleite, in YDB sediments and Greenland ice, continue to be presented as the strongest evidence for an impact [2][3][4][5][6][7][8].Nanodiamonds are reported to occur in YDB sediments and in millimeter-scale carbon forms (variously termed, 'glass-like', 'spherules', and 'elongates') in those sediments. The carbon forms are proposed to be products of the impact [2,7] and/or the resulting continent-wide wildfires [2,4].…”

“…Further, we determined that measurements of a nanodiamond abundance spike at the YDB reported by [7], and other impact proponents that used similar techniques, are critically flawed and are not credible [9]. Note, that the majority of the reported YDB nanodiamonds are not diamond, but rather are a controversial modified form of diamond termed 'n-diamond' [3][4][5][6][7][8]. Controversial 'i-carbon' is also reported at the YDB of many sites [6,7].…”

“…Controversial 'i-carbon' is also reported at the YDB of many sites [6,7]. While neither are diamond polytypes, impact proponents describe them as nanodiamonds [3][4][5][6][7][8]. In YDB sediments, 'n-diamonds' are usually reported at higher abundances than diamond [6,7].…”