Tektite research 1936–1990*

Barnes, V. E.

doi:10.1111/j.1945-5100.1990.tb00990.x

Cited by 21 publications

(15 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Barnes (e.g., Barnes and Pitakpaivan, 1962;Barnes, 1989Barnes, , 1990, mainly from studying Muong Nong-type tektites, suggested that the Australasian tektites have originated from an impact of a "diffuse object such as a comet." However, it is not easy to understand how the impact of a cometary nucleus would differ from that of an asteroid because upon passing through the atmosphere any cometary coma would be stripped off.…”

Section: Australasian Strewn Fieldmentioning

confidence: 99%

Tektite origin by hypervelocity asteroidal or cometary impact: Target rocks, source craters, and mechanisms

Koeberl¹

1992

Geological Society of America Special Papers

123

164

View full text Add to dashboard Cite

Tektites are natural glasses that occur on earth in four distinct strewn fields (North American, Central European, Ivory Coast, and Australasian). Geochemical arguments have shown that tektites have been derived by hypervelocity impact melting from terrestrial upper crustal rocks, most likely sediments. The contents of Be-10 in tektites are evidence for a derivation of tektites from surface rocks, thus precluding an origin from greater depth in the crater. For two of the four tektite strewn fields (Ivory Coast, Central European), a possible connection to impact craters (Bosumtwi, and Ries, respectively) has been suggested on the basis of chemical, isotopic, and age data. No clear crater identifications have been made for the North American or Australasian strewn fields, although there are good candidates for both. Even though the geochemistry of tektites is in unequivocal favor of an origin by impact melting of terrestrial rocks, the unambiguous demonstration of the presence of an extraterrestrial contribution to the chemistry of tektites remains a problem. However, recent osmium isotope studies have shown that there is a clear meteoritic signature in at least some tektites. The exact mechanism of tektite formation is still not obvious, although some facts become increasingly clear. Tektite production requires specific impact conditions-otherwise there would be many more tektite strewn fields connected to the 150 or so known impact craters. Tektites are produced by nonequilibrium shock melting of surficial rocks, and the superheated melt may be subjected to a plasma phase during which they are subjected to partial reduction. They are then lofted through the atmosphere (probably in the wake of the expanding vapor cloud), quenched, and distributed over a geographically extended area-the strewn field. Some tektites solidify in a near-vacuum and re-enter the atmosphere. During the re-entry they melt again and form ablation-shaped tektites. Larger tektites, from a lower part of the target stratigraphy, are only distributed closer to the source crater. Many of them are more inhomogeneous melts and show a layered structure; they are called Muong Nong-type tektites. The study of tektites and the identification of possible new strewn fields provide important contributions toward the understanding of impact cratering.

show abstract

Section: Australasian Strewn Fieldmentioning

confidence: 99%

Tektite origin by hypervelocity asteroidal or cometary impact: Target rocks, source craters, and mechanisms

Koeberl¹

1992

Geological Society of America Special Papers

123

164

View full text Add to dashboard Cite

show abstract

“…Tektites, glassy or crystalline bodies ranging in size from micrometers to 0.1 m, are ejecta from terrestrial impact craters (e.g., Taylor 1973;King 1977;Barnes 1990;Koeberl 1990). The majority of papers on tektites have been dedicated to determining the source of tektites or to attempting to discover the terrestrial crater from which they were ejected.…”

Section: Introductionmentioning

confidence: 99%

A laboratory model of splash‐form tektites

Elkins-Tanton

Aussillous

Bico

et al. 2003

Meteorit & Planetary Scien

View full text Add to dashboard Cite

Abstract-Splash-form tektites are generally acknowledged to have the form of bodies of revolution. However, no detailed fluid dynamical investigation of their form and stability has yet been undertaken. Here, we review the dynamics and stability of spinning, translating fluid drops with a view to making inferences concerning the dynamic history of tektites. We conclude that, unless the differential speed between the molten tektite and ambient is substantially less than the terminal velocity, molten tektites can exist as equilibrium bodies of revolution only up to sizes of 3 mm. Larger tektites are necessarily non-equilibrium forms and so indicate the importance of cooling and solidification during flight. An examination of the shapes of rotating, translating drops indicates that rotating silicate drops in air will assume the shapes of bodies of rotation if their rotational speed is 1% or more of their translational speed. This requirement of only a very small rotational component explains why most splash-form tektites correspond to bodies of revolution. A laboratory model that consists of rolling or tumbling molten metallic drops reproduces all of the known forms of splashform tektites, including spheres, oblate ellipsoids, dumbbells, teardrops, and tori. The laboratory also highlights important differences between rolling drops and tumbling drops in flight. For example, toroidal drops are much more stable in the former than in the latter situation.

show abstract

“…This may be the result oflower formation temperatures compared to splash-form tektites. They probably formed from the same or a very similar source material, but were less thoroughly heated (see e.g., Barnes, 1990, for petrographic evidence for this statement, based on vesicularity oflechatelierite particles) and have, therefore, lost less of their volatile element content than the splash form tektites. Muong Nong-type tektites may be the key to some important questions.…”

Section: Geochemistry and Petrography Of Tektitesmentioning

confidence: 92%

The Sedimentary Record of Impact Events

Koeberl

2001

Accretion of Extraterrestrial Matter Throughout Earth’s History

View full text Add to dashboard Cite

Some impact events in the geological record have been recognized because of the discovery of ejecta layers. Ejecta are classified into proximal ejecta, which are found in the immediate vicinity of an impact crater, within <5 crater radii from the rim, and distal ejecta, i.e., those that occur at considerable distances from the source crater (>5 crater radii from the crater rim). Distal ejecta consist of (usually fine-grained) rock and mineral fragments, and/or contain impact glasses.

show abstract

Tektite research 1936–1990*

Cited by 21 publications

References 66 publications

Tektite origin by hypervelocity asteroidal or cometary impact: Target rocks, source craters, and mechanisms

Tektite origin by hypervelocity asteroidal or cometary impact: Target rocks, source craters, and mechanisms

A laboratory model of splash‐form tektites

The Sedimentary Record of Impact Events

Contact Info

Product

Resources

About