Nanometre-size diamonds in the Cretaceous/Tertiary boundary clay of Alberta

Carlisle, D. B.; Braman, Dennis R.

doi:10.1038/352708a0

Cited by 70 publications

(27 citation statements)

References 15 publications

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“…These observations are confirmed by our own work at 22 YDB sites. Similarly, NDs have not been found above or below the K-Pg impact layer (Carlisle and Braman 1991;Gilmour et al 1992;Bunch et al 2008), even though biomass burning is accepted as having been broadly pervasive over the K-Pg boundary interval (Wolbach 1990).…”

Section: Potential Origin From Volcanism or In The Mantlementioning

confidence: 99%

“…Daulton (2012) and Boslough et al (2012) questioned whether YDB NDs are robust cosmic-impact markers. However, cubic NDs are widely accepted to have formed during the K-Pg impact event and were not found in sediment before or after the event (Carlisle and Braman 1991;Gilmour et al 1992;Hough et al 1997Hough et al , 1999 berta, Canada. The K-Pg NDs were reported to range in size from 1 nm to 30 mm, whereas YDB NDs are smaller, spanning a narrower range of ≈1 to ≈2.9 mm, perhaps because that older impact was larger and more energetic than the YDB event.…”

Section: Introductionmentioning

confidence: 98%

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Nanodiamond-Rich Layer across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP

Kinzie¹,

Hee

Stich

et al. 2014

The Journal of Geology

170

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. A B S T R A C TA major cosmic-impact event has been proposed at the onset of the Younger Dryas (YD) cooling episode at ≈12,800 ‫ע‬ 150 years before present, forming the YD Boundary (YDB) layer, distributed over 150 million km 2 on four continents. In 24 dated stratigraphic sections in 10 countries of the Northern Hemisphere, the YDB layer contains a clearly defined abundance peak in nanodiamonds (NDs), a major cosmic-impact proxy. Observed ND polytypes include cubic diamonds, lonsdaleite-like crystals, and diamond-like carbon nanoparticles, called n-diamond and i-carbon. The ND abundances in bulk YDB sediments ranged up to ≈500 ppb (mean: 200 ppb) and that in carbon spherules up to ≈3700 ppb (mean: ≈750 ppb); 138 of 205 sediment samples (67%) contained no detectable NDs. Isotopic evidence indicates that YDB NDs were produced from terrestrial carbon, as with other impact diamonds, and were not derived from the impactor itself. The YDB layer is also marked by abundance peaks in other impact-related proxies, including cosmic-impact spherules, carbon spherules (some containing NDs), iridium, osmium, platinum, charcoal, aciniform carbon (soot), and high-temperature melt-glass. This contribution reviews the debate about the presence, abundance, and origin of the concentration peak in YDB NDs. We describe an updated protocol for the extraction and concentration of NDs from sediment, carbon spherules, and ice, and we describe the basis for identification and classification of YDB ND polytypes, using nine analytical approaches. The large body of evidence now obtained about YDB NDs is strongly consistent with an origin by cosmic impact at ≈12,800 cal BP and is inconsistent with formation of YDB NDs by natural terrestrial processes, including wildfires, anthropogenesis, and/or influx of cosmic dust.

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Section: Potential Origin From Volcanism or In The Mantlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Nanodiamond-Rich Layer across Three Continents Consistent with Major Cosmic Impact at 12,800 Cal BP

Kinzie¹,

Hee

Stich

et al. 2014

The Journal of Geology

170

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“…In Caravaea an organic associalion of Ir has been proposed; Schmitz (1988) considered thal 50 % of the bulk sample Ir is associated with organic eompounds. On the other hand, the presence of relict carOOn (microdiamonds) has been reponed in the Crelaceousffertiary OOundary layer at Red Deer VaIley (Alberta, Canada) by Carlisle & Braman (1991). Recently an exlraterrestrial origin for these mierodiamonds was confirmed by Carlisle (1992).…”

Section: Discussionmentioning

confidence: 99%

Untitled

Ortega-Huertas¹,

Ruiz²,

Acquafredda³

et al. 1994

Estud. geol.

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The abundant spherules present in the Cretaceous-Tertiary boundary layer at Caravaca are diagenetically transformed to potassium feldspar. Before our study no possible relicts of the precursor material had been reported. but in this paper we describe the presence of cores in these spherules that could represent a relict of the «unknown precursor». These cores are made up of C mixed with Si. Mg. AL Cr. Ca among other elements. Laser Ablation System analysis also reveals an enrichment in pe; E could suggest an extraterrestrial origin for this material. PI. Pd and Ir do not show a chondritic ratio: however. asevere modification of their concentration could be expected during the early diagenetic processes. RESUMENLas esférulas existentes en la lámina de sedimento del tránsito Cretácico-Terciario de la sección de Caravaca han sido transformadas diagenéticamente a feldespato potásico. En este trabajo se describe la existencia de núcleos encontrados en el interior de las esférulas. los cuales' pueden representar relictos del material precursor. Dichos núcleos están constituidos por C. Si. Mg, AL Cr y Ca entre otros elementos. Se pone de relieve, por vez primera, su notable enriquecimiento en elementos del grupo del platino, cuyas relaciones no condríticas pueden ser debidas a la existencia de importantes modificaciones en su concentración inicial causadas por los procesos diagenéticos y por la existencia de materia orgánica.

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“…Compared to the mammoth efforts poured into DPP in the 1980s and early 1990s, work in the Edmonton Group was somewhat slower in starting, although some notable discoveries were made (e.g., Figs. 4A, 4B) and studies conducted in the decade following the museum's opening, and carrying through to the present (e.g., Fox and Naylor 1986;Carlisle and Braman 1991;Eberth and O'Connell 1995;Zelenitsky et al 2012b;Eberth et al 2013). With the re-discovery in 1997 of Barnum Brown's lost Albertosaurus bonebed in Dry Island Buffalo Jump Provincial Park (see Currie and Koppelhus 2010), the RTMP began focusing more attention on the Edmonton Group (e.g., numerous papers in Currie and Koppelhus 2010;Eberth and Braman 2012;Eberth et al 2013).…”

Section: Fieldworkmentioning

confidence: 99%