Cosmic nickel-iron alloy spherules from Pleistocene sediments, Alberta, Canada

Bi, Dong; Morton, R. D.; Wang, Kun

doi:10.1016/0016-7037(93)90359-5

Cited by 29 publications

(14 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Metallic micrometeorites and solid cosmic microspherules, which are a part of the constant cosmic influx, usually contain high concentrations of Ni. However, hollow magnetic microspherules from elsewhere either display low concentrations of Ni (up to several per cents) or are virtually Ni free (Bonté et al 1987;Koeberl and Hagen 1989;Bi et al 1993;Marini et al 2004;Stankowski et al 2006;Genge et al 2008;Guaita and Martegani 2008;van Ginneken et al 2010;Rudraswami et al 2014aRudraswami et al , 2014b. However, although high Ni content indicates extraterrestrial origin, low concentrations of Ni do not rule out such an origin (e.g.…”

Section: Mms#1mentioning

confidence: 99%

Implications from chemical, structural and mineralogical studies of magnetic microspherules from around the lower younger dryas boundary (new mexico, usa)

Andronikov

Andronikova

Loehn

et al. 2016

Geografiska Annaler: Series A, Physical Geography

View full text Add to dashboard Cite

Hollow magnetic microspherules from along the lower Younger Dryas boundary (c. 12.9 ka bp) in New Mexico (USA) were studied using scanning electron microscopy, electron probe microanalysis, X‐ray diffraction, and laser‐ablation inductively coupled‐plasma mass spectrometry methods. The shell of the microspherules (10–15% of the spherule's diameter) displays dendritic surface textures, which are likely due to quenching during rapid cooling of molten material. Structurally, multiple single‐magnetite crystals attached together form the bulk of the microspherules. Iron dominates the microspherules’ composition (∼90% FeOtot), Mn is the second most abundant element (up to 0.4% MnO), Al is detected in low concentrations (<0.30% of Al2O3). Among the trace elements, the rare earth elements display slightly fractionated patterns with concentrations of 0.1–1.0× CI chondrite. The microspherules contain elevated concentrations of Ni relative to detrital magnetite (up to 435 ppm) and very low concentrations of Ti (down to 5 ppm). Chemical, structural and mineralogical features of the microspherules do not contradict the existing models of the formation during ablation while a meteoroid goes through the Earth's atmosphere. Elevated concentrations of the magnetic microspherules in sediments can be a stratigraphic marker for the lower Younger Dryas boundary in North America.

show abstract

Section: Mms#1mentioning

confidence: 99%

Implications from chemical, structural and mineralogical studies of magnetic microspherules from around the lower younger dryas boundary (new mexico, usa)

Andronikov

Andronikova

Loehn

et al. 2016

Geografiska Annaler: Series A, Physical Geography

View full text Add to dashboard Cite

show abstract

“…In these objects, metallic Fe‐Ni most commonly occurs as spheroids, rounded particles, or coarse anhedral grains. Ni‐Fe alloy with Ni > 90% forms the metallic cores of magnetic cosmic spherules (impact and nonimpact) found in deep‐sea sediments, ice caps and ancient sedimentary successions on Earth [ El Goresy , 1968; Kelly et al , 1974; Bi et al , 1993]. Ni 0 particles from TAG appear in sediment situated among layers rich in cosmic microspherules (Figure 1c).…”

Section: Resultsmentioning

confidence: 99%

“…This, however, does not completely rule out the possibility of cosmic genesis of Ni 0 particles. A cogent argument against the cosmic origin of the TAG Ni 0 is their form: flat, flake‐like in contrast to the spherical, drop‐ or tear‐like shape of the extraterrestrial Fe‐Ni particles [ El Goresy , 1968; Kelly et al , 1974; Czajkowski , 1987; Bi et al , 1993]. …”

Section: Resultsmentioning

confidence: 99%

“…Chalcophile (Cu, Zn, Pb) and siderophile (Fe, Co, Ni, PGE) elements are often found in native state, and their occurrences do not provoke particular discussions. Nickel‐iron alloy grains attributed to either cosmic [ Bi et al , 1993] or mantle [ Bai et al , 2000] input are frequently described, whereas reports on pure native Ni 0 are rare.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Native nickel in the TAG hydrothermal field sediments (Mid‐Atlantic Ridge, 26°N): Space trotter, guest from mantle, or a widespread mineral, connected with serpentinization?

Dekov

2006

J. Geophys. Res.

View full text Add to dashboard Cite

[1] Tiny metallic particles have been found in the sediments of the Trans-Atlantic Geotraverse (TAG) hydrothermal field, Mid-Atlantic Ridge (MAR). The metallic grains are almost pure Ni and have compositional and structural characteristics similar to those of other terrestrial metallic Ni 0 occurrences. Native nickel grains, documented here for the first time in oceanic sediments, appear in calcareous oozes intercalated with metalliferous layers, layers with bedrock rubble, and sporadically scattered cosmic microspherules. There are three possibilities for the metallic Ni 0 genesis: (1) cosmic, (2) lower mantle at the core-mantle boundary, or (3) upper mantle/lower crust. The flake-like appearance of the Ni 0 grains rules out cosmic ablation origin. No unequivocal evidence was found that the Ni 0 particles could have formed under high-pressure conditions similar to those at the core-mantle boundary. Ni 0 formation through seawater serpentinization of the upper mantle/lower crust is the most plausible mechanism. At the slow spreading MAR, seawater penetrates down through highly fractured crest zone and serpentinizes the olivine and pyroxene of the upper mantle/lower crust ultramafics/mafics. Serpentinization results in the generation of highly reduced volatile species: H 2 and hydrocarbons. In such an extremely reduced environment, Fe and other transition metals (Co, Ni, Cu, Zn) released from olivines and pyroxenes tend to appear as native metals if fS 2 approaches 0. The lightened serpentinized blocks uplift and expose the serpentinized ultramafics/mafics at the rift valley's walls. I speculate that tectonic movements and weathering could liberate the native metallic grains scattered in the serpentinized rocks, which may then have been dispersed in the proximate sediments by near-bottom currents.

show abstract

“…A significant proportion of the metallic liquid oxidizes during entry heating, leaving a high Ni metallic core, very occasionally with a Pt group‐rich nugget. Depending on the deceleration experienced, metallic cores of the spherules migrate to the front of the particle and separate, leaving a remnant that comprises a Fe‐oxide spherule free of Ni (Bi et al ., ; Yada et al ., ). Similar I‐type spherules depleted in Ni occur in Ordovician rocks of the Durness Group in NW Scotland (Dredge et al ., ), in Oligocene sediments in the coastal plain of South Carolina, USA (Taylor et al ., ), and in modern collections from the Transantarctic Mountains (Rochette et al ., ) and the Central Indian Ocean (Parashar et al ., ).…”

Section: Discussionmentioning

confidence: 99%

Cosmic spherules from the Ordovician of Argentina

et al. 2012

View full text Add to dashboard Cite

The discovery of magnetic spherules in acid‐insoluble residues from conodont samples encouraged a systematic search for Ordovician micrometeorites from northwestern Argentina. Some 220 melted micrometeorites were recovered from the magnetic fraction of six samples (total rock weight: 23 kg) from the Cordillera Oriental (Santa Rosita Formation) and 17 from five samples (total rock weight: 8.9 kg) from the Argentine Precordillera (Las Aguaditas, Gualcamayo and Las Vacas formations). The specimens resemble I‐type cosmic spherules, in their chemistry and distinct dendritic and polygonal crystalline structures. They represent a flux of micrometeorites several orders of magnitude greater than present. The wide differences in spherule abundance between the Precordillera and the Cordillera Oriental samples could reflect uncertainties in the sedimentary rates or temporal variations in the flux of extraterrestrial matter to Earth. The micrometeorite‐bearing formations span the late Tremadocian to the late Darriliwian (~480–460 Ma), which is consistent with a period of elevated flux of extraterrestrial material, as recorded several thousand kilometres away from coeval horizons in Scotland, Sweden and central China. Copyright © 2012 John Wiley & Sons, Ltd.

show abstract

Cosmic nickel-iron alloy spherules from Pleistocene sediments, Alberta, Canada

Cited by 29 publications

References 25 publications

Implications from chemical, structural and mineralogical studies of magnetic microspherules from around the lower younger dryas boundary (new mexico, usa)

Implications from chemical, structural and mineralogical studies of magnetic microspherules from around the lower younger dryas boundary (new mexico, usa)

Native nickel in the TAG hydrothermal field sediments (Mid‐Atlantic Ridge, 26°N): Space trotter, guest from mantle, or a widespread mineral, connected with serpentinization?

Cosmic spherules from the Ordovician of Argentina

Contact Info

Product

Resources

About