<i>Principles of Meteoritics</i>

Krinov, E. L.; Brown, Harrison; Anders, Edward

doi:10.1063/1.3057157

Cited by 25 publications

(33 citation statements)

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“…In the ordinary chondrites the fusion crust usually exhibits three well developed zones with a melted crust overlying an outer substrate dominated by silicate glass veins and an inner substrate containing metal and sulphide veins (Genge and Grady, 1999). Equivalent zones (1, 2 and 3) were also recognized by Ramdohr (1967) and by Krinov (1960). The outer substrate is present only in the EH chondrites and is poorly developed.…”

Section: The Textures and Mineralogies Of Fusion Crustsmentioning

confidence: 99%

“…The mineralogy and petrology of fusion crusts have been little studied, since the alteration that results from heating obscures the 'primary' characteristics that make meteorites useful as samples of ancient solar system materials. Pioneering studies of meteorite fusion crusts (Ramdohr, 1967(Ramdohr, , 1973Krinov, 1960) provided many interesting insights into their mineralogy but are limited by the lack of microanalysis. Studies of fusion crust, however, have provided estimates of the mass of meteoritic stones prior to their entry into the Earth's atmosphere (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Unequilibrated assemblages of sulphide, metal and oxide in the fusion crusts of the enstatite chondrite meteorites

Genge

Grady

1999

Mineral. mag.

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The fusion crusts of meteorites form due to heating during atmospheric entry and have mineralogies which are strongly influenced by changes in oxidation state. We have studied the fusion crusts of the most reduced primitive meteorite group, the enstatite chondrites, since they should demonstrate pronounced changes on oxidation. The fusion crusts are dominated by highly unequilibrated assemblages of sulphide, metal and oxide with compositions indicative of progressive oxidation by the reaction with atmospheric oxygen. Troilite becomes depleted in Ti, Cr and Mn, and enriched in Ni with increasing oxidation. Enrichments in the Ni-contents of kamacite and depletions in Si-content also occur with oxidation, although contemporaneous enrichments in Si within metal droplets occurs by partial melting. Assemblages dominated by Fe-oxide are found within fusion crusts as reaction rims on metal, as veins and within troilite-metal assemblages as droplets and formed by oxidation of metal during heating. Despite the evidence for large increases in redox state during heating, fusion crusts also contain lithophile sulphides indicating a high degree of disequilibrium during the atmospheric reprocessing of enstatite chondrite materials. Based on comparisons with experimental phase relations, ablation rates of 0.08-0.25 cm s -1 are predicted from the thermal gradients recorded in fusion crusts; these rates are broadly similar to those suggested for other meteorite groups.

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Section: The Textures and Mineralogies Of Fusion Crustsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Unequilibrated assemblages of sulphide, metal and oxide in the fusion crusts of the enstatite chondrite meteorites

Genge

Grady

1999

Mineral. mag.

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“…The impact, if any, was probably due to small pieces falling at the terminal velocity of 100 mls to 300 mls with much less energy than an earthquake (Heide, 1957). Indeed, most meteorite falls result in slight effects at the impact site (Krinov, 1960). The "shock caused by the fall" referred to by the newspaper was most likely a sonic boom, or an explosion high above the earth rather than an impact and the "great column of steam" was almost certainly the smoke trail.…”

Section: Field Investigationmentioning

confidence: 99%

The Saskatchewan Fireball of 1922 and a Possible Link With the Wynyard Chondrite

Gendzwill¹,

Stauffer²

1984

Meteoritics

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A brilliant smoking meteor appeared in a clear sky in bright sunlight at 11 a.m., July 24, 1922 near Wynyard, Saskatchewan, Canada. The sight and thunderous sounds were witnessed by many hundreds of people in the rural district but no craters or meteorites were found at that time. Investigation and interviews with surviving witnesses in 1981 indicated a defined area near Big Quill Lake in which a meteorite may have fallen. Field investigation led to the Wynyard meteorite which had been found by a farmer sometime in the late 1960's at 104° 11'W 51°33'N. The Wynyard meteorite is a chondrite weighing 3.5 kg. It is moderately weathered and it may or may not have been part of the 1922 fall.

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“…Although the range of possible velocities of incoming meteorites is between 11 and 70 km S-1 (Krinov, 1960), the majority of initial velocities are below 25 km S-1 (McCrosky, 1970), with a mean of 16.5 km S-1 (Whipple and Hughes, 1955).…”

Section: Rates and Velocities Of Impactsmentioning

confidence: 99%

“…Smaller meteorites, given that some mass survives ablation, willbe slowed to their terminal fall speed, typically 100 to 200 m S-1 (Heide, 1964), and at impact will be travellingalmost vertically (Krinov, 1960). During descent meteorites are subject to considerable stress from air drag (Krinov, 1966), which frequently causes fragmentation.…”

Section: Rates and Velocities Of Impactsmentioning

confidence: 99%