Cosmic dust and micrometeorites in the transitional clay layer at the Cretaceous-Paleogene boundary in the gams section (Eastern Alps): Morphology and chemical composition

Grachev, A. F.; Korchagin, O. A.; Tselmovich, V. A.; Kollmann, Heinz A.

doi:10.1134/s1069351308070069

Cited by 21 publications

(21 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Metal vapors could have been raised by the explosion to a height up to tens of kilometers, where their crystallization took place (Grachev et al . ). Because of the difference in evaporation temperatures (boiling point for Fe is 2750°C, and for Ni is 2732°C, both of which are much lower than boiling points for the PGE), the growth from the vapor phase gives an explanation for the lack of Ni and especially the PGE in the magnetic microspherules of the studied type (cf.…”

Section: Discussionmentioning

confidence: 97%

“…; Grachev et al . ; Voldman et al . and references therein), the element is useful to distinguish between terrestrial and extraterrestrial magnetic particles.…”

Section: Discussionmentioning

confidence: 99%

“…Because magnetic particles of cosmic origin contain only negligible amounts of Ti (e.g. Szöőr et al 2001;Grachev et al 2008;Voldman et al 2012 and references therein), the element is useful to distinguish between terrestrial and extraterrestrial magnetic particles. For example, volcanic magnetic microspherules (real microspherules, not rounded crystals) are always titaniferous, (usually >10% of Ti) and, as important, are never hollow (Cornen et al 1992;Grebennikov 2011;Voldman et al 2012 and references therein).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

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: Discussionmentioning

confidence: 97%

“…; Grachev et al . ; Voldman et al . and references therein), the element is useful to distinguish between terrestrial and extraterrestrial magnetic particles.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

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

“…Cosmic dust derives from the ablation of meteoritic bodies, cometary dust, terrestrial impact, and passage of the solar system through an interstellar cloud (18,19). Between 4,000-10,000 t of cosmic dust is thought to land on the earth's surface annually (20). By some estimates, a square meter collects about one 10-μm particle per day and one 100-μm particle per year (17,21).…”

Section: Discussionmentioning

confidence: 99%

“…The Clovis surface at the top of the F 1 channel fill might be expected to have more cosmic dust than the sides of the valley if it concentrated there during activation of the Clovis channel. Cosmic dust therefore cannot be overlooked as a reasonable explanation for the presence of an ET component, including nanodiamonds (20,22,23), from the Murray Springs strata.…”

Section: Discussionmentioning

confidence: 99%

The Murray Springs Clovis site, Pleistocene extinction, and the question of extraterrestrial impact

Haynes

Boerner

Domanik

et al. 2010

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

View full text Add to dashboard Cite

Some of the evidence for the recent hypothesis of an extraterrestrial impact that caused late Pleistocene megafaunal extinctions [Firestone et al. (2007) Proc Natl Acad Sci USA 104:16016–16021] was based upon samples collected at Murray Springs, a Clovis archaeological site in southeastern Arizona. Here we describe sampling and analyses of magnetic separates from within, above, and below the lower Younger Dryas boundary (LYDB) black mat at Murray Springs, as well as radiation measurements from the LYDB at Murray Springs and two other well-stratified Clovis sites. The main magnetic fraction at Murray Springs is maghemite. Magnetic microspherules have terrestrial origins but also occur as cosmic dust particles. We failed to find iridium or radiation anomalies. The evidence for massive biomass burning at Murray Springs is addressed and found to be lacking. We could not substantiate some of the claims by Firestone and others, but our findings do not preclude a terminal Pleistocene cosmic event.

show abstract

Determination of element composition and extraterrestrial material occurrence in moss and lichen samples from King George Island (Antarctica) using reactor neutron activation analysis and SEM microscopy

Mróz

Szufa

Frontasyeva

et al. 2017

Environ Sci Pollut Res

View full text Add to dashboard Cite

Seven lichens (Usnea antarctica and U. aurantiacoatra) and nine moss samples (Sanionia uncinata) collected in King George Island were analyzed using instrumental neutron activation analysis, and concentration of major and trace elements was calculated. For some elements, the concentrations observed in moss samples were higher than corresponding values reported from other sites in the Antarctica, but in the lichens, these were in the same range of concentrations. Scanning electron microscopy (SEM) and statistical analysis showed large influence of volcanic-origin particles. Also, the interplanetary cosmic particles (ICP) were observed in investigated samples, as mosses and lichens are good collectors of ICP and micrometeorites.Electronic supplementary materialThe online version of this article (10.1007/s11356-017-0431-2) contains supplementary material, which is available to authorized users.

show abstract

Cosmic dust and micrometeorites in the transitional clay layer at the Cretaceous-Paleogene boundary in the gams section (Eastern Alps): Morphology and chemical composition

Cited by 21 publications

References 45 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)

The Murray Springs Clovis site, Pleistocene extinction, and the question of extraterrestrial impact

Determination of element composition and extraterrestrial material occurrence in moss and lichen samples from King George Island (Antarctica) using reactor neutron activation analysis and SEM microscopy

Contact Info

Product

Resources

About