Magnetite Spherules in Miocene Versus Recent Sands of New Jersey

Puffer, John H.

doi:10.1111/j.1945-5100.1974.tb01196.x

Cited by 3 publications

(3 citation statements)

References 7 publications

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“…Magnetic spherule surface morphology is distinctive when created by processes involving high temperatures followed by rapid cooling, such as during meteoritic atmospheric ablation and impacts (4)(5)(6)(7)(8)(9)(10)(11)(12). For identification of spherule surficial morphology (microstructure), we followed the work of Zagurski et al (25), who used SEM imaging to develop indices of magnetic particles in soil samples extracted from 33 Russian sites.…”

Section: Resultsmentioning

confidence: 99%

“…Sedimentary iron-and silica-rich spherules are believed to form from the influx of ET material, directly by meteoritic ablation and indirectly during the sudden cooling of molten terrestrial ejecta from a cosmic impact (6)(7)(8)(9)(10). They can also be formed by volcanism, anthropogenic processes, biogenesis, and diagenesis (11,12) and, in the laboratory, by electrostatic discharge (13). Consequently, determining the nature and origin of observed spherules is essential.…”

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confidence: 99%

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Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis

LeCompte

Goodyear

Demitroff

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Firestone et al. sampled sedimentary sequences at many sites across North America, Europe, and Asia [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 106:16016–16021]. In sediments dated to the Younger Dryas onset or Boundary (YDB) approximately 12,900 calendar years ago, Firestone et al. reported discovery of markers, including nanodiamonds, aciniform soot, high-temperature melt-glass, and magnetic microspherules attributed to cosmic impacts/airbursts. The microspherules were explained as either cosmic material ablation or terrestrial ejecta from a hypothesized North American impact that initiated the abrupt Younger Dryas cooling, contributed to megafaunal extinctions, and triggered human cultural shifts and population declines. A number of independent groups have confirmed the presence of YDB spherules, but two have not. One of them [Surovell TA, et al. (2009) Proc Natl Acad Sci USA 104:18155–18158] collected and analyzed samples from seven YDB sites, purportedly using the same protocol as Firestone et al., but did not find a single spherule in YDB sediments at two previously reported sites. To examine this discrepancy, we conducted an independent blind investigation of two sites common to both studies, and a third site investigated only by Surovell et al. We found abundant YDB microspherules at all three widely separated sites consistent with the results of Firestone et al. and conclude that the analytical protocol employed by Surovell et al. deviated significantly from that of Firestone et al. Morphological and geochemical analyses of YDB spherules suggest they are not cosmic, volcanic, authigenic, or anthropogenic in origin. Instead, they appear to have formed from abrupt melting and quenching of terrestrial materials.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis

LeCompte

Goodyear

Demitroff

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…В силикатных расплавах доказана возможность возникновения несмесимости, в результате которой расплав распадается на две несмесимые жидкости разного состава [71,85]. Ликват меньшего объема при этом образует жидкие микросферулы в матрице ликвата большего объема [48,64].…”

Section: медь-золото-серебряные микросферулыunclassified

Silicate, Iron Oxide and Copper-Gold-Silver Microspherules in Ores and Pyroclastics of the Kostenginskoye Iron Ore Deposit (Russian Far East)

Бердников¹,

Nevstruev²,

Kepezhinskas³

et al. 2021

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Iron-oxide ores and pyroclastics from the Kostenginskoye deposit in the Malyi Khingan (Russian Far East) contain numerous silicate, iron-oxide, and copper-gold-silver microspherules. Silicate spherules are composed of immiscible iron- and silica-rich glasses, gas cavities and mineral inclusions. Iron-oxide spherules include magnetite with minor ilmenite and Fe-rich silicate glass. Copper-gold-silver spherules contain inclusions predominantly of copper oxide compositions. The studied microspherules are considered to have formed during the rapid ascent of metal-silicate melts from depth and their degassing controlled by liquid immiscibility differentiation. The paper discusses the possible volcanic origin of iron-oxide ores and the associated noble metal mineralization for the deposits of this type.

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Silicate, Fe-Oxide, and Au–Cu–Ag Microspherules in Ores and Pyroclastic Rocks of the Kostenga Iron Deposit, in the Far East of Russia

Бердников

Nevstruev

Kepezhinskas

et al. 2021

Russ. J. of Pac. Geol.

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Magnetite Spherules in Miocene Versus Recent Sands of New Jersey

Cited by 3 publications

References 7 publications

Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis

Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis

Silicate, Iron Oxide and Copper-Gold-Silver Microspherules in Ores and Pyroclastics of the Kostenginskoye Iron Ore Deposit (Russian Far East)

Silicate, Fe-Oxide, and Au–Cu–Ag Microspherules in Ores and Pyroclastic Rocks of the Kostenga Iron Deposit, in the Far East of Russia

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