Deep-sea spherules from Pacific clay: mass distribution and influx rate

Murrell, M. T.; Davis, Philip A.; Nishiizumi, K.; Millard, H.T.

doi:10.1016/0016-7037(80)90204-5

Cited by 55 publications

(28 citation statements)

References 17 publications

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“…The proportions of the spherule types were similar to those of the much larger DSS collection, which was both collected and processed magnetically (Table I). Murrell et al (1980) came to a similar conclusion when they magnetically extracted spherules from 411 kg of deep-sea mud collected nonmagnetically and found no spherules in the nonmagnetic fractions. This conclusion would probably not hold for deposits rich in glassy, iron-poor particles.…”

Section: Sample Collection and Preparationsupporting

confidence: 56%

Cosmic spherules in the geologic record

Taylor

Brownlee

1991

Meteoritics

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Abstract-Cosmic spherules obtained from the Greenland ice cap, deep-sea sediments, and ancient oceanic deposits of Eocene and Jurassic age were chemically and texturally compared. The proportions of spherule types were found to change as a function of time, with the number of iron spherules increasing as the age of the sample increased. It is not yet possible, however, to determine if the variation in spherule types represents a real change in the meteoroid complex or is a result of differential weathering of the spherules in the Earth's environment.The age of these spherules ranges from less than 3000 years to about 190 million years. Although only a few spherules older than 500000 years are chemically unaltered, textural information is available even from the oldest spherules and, by comparison with contemporary spherules, gives some insight into the original compositions of the particles.

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Section: Sample Collection and Preparationsupporting

confidence: 56%

Cosmic spherules in the geologic record

Taylor

Brownlee

1991

Meteoritics

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“…Taking the meteor density to be 3 g/cm 3 , this distribution yields masses between 10 −12 and 10 −6 g. Note that Evans (1966) used δ = 1 g/cm 3 to calculate the mass of the meteors. The range of our results will not change significantly if we use 1 g/cm 3 or other common meteor densities (Whipple 1952, Murrell et al 1980McDonnell et al 1998). …”

Section: Discussionmentioning

confidence: 55%

Micrometeor Observations Using the Arecibo 430 MHz Radar I. Determination of the Ballistic Parameter from Measured Doppler Velocity and Deceleration Results

Janches

Mathews

Meisel

et al. 2000

Icarus

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“…The DSS are much more weathered (e.g., missing interstitial glass) and have proportionally far fewer glass and cryptocrystalline spherules and many more I-type and G-type spherules than either polar collection ( Table 4). Because the magnetically and nonmagnetically collected DSS are similar (Murrell et al, 1980;Taylor and Brownlee, 1991), collection technique does not account for the paucity of glass spherules. More likely, glass-rich spherules dissolve and I-type spherules persist in deepsea sediments (Blanchard et al, 1980;Kyte, 1983).…”

Section: --mentioning

confidence: 99%

Numbers, types, and compositions of an unbiased collection of cosmic spherules

Taylor

Lever

Harvey

2000

Meteorit & Planetary Scien

181

326

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Abstract-Micrometeorites collected from the bottom of the South Pole water well (SPWW) may represent a complete, well-preserved sample of the cosmic dust that accreted on Earth from 1100-1500 A.D. We classified 1588 cosmic spherules in the size range 50-800 pm. The collection has 41% barred olivine spherules, 17% glass spheres, 12% cryptocrystalline spherules, 1 1% porphyritic olivine spherules, 12% relicgrain-bearing spherules, 3% scoriaceous spherules, 2% I-type spherules, 1 % Ca-Al-Ti-rich (CAT) spherules, and 1% G-type spherules. We also found bubbly glass spherules, spherules with glass caps, and ones with sulfide coatings-particles that are absent from other collections. A classification sequence of the stony spherules (scoriaceous, relic-grain-bearing, porphyritic, barred olivine, cryptocrystalline, glass, and CAT) is consistent with progressive heating and evaporation of Fe from chondritic materials. The modem-day accretion rate and size distribution measured at the SPWW can account for the stony spherules present in deep-sea collection through preferential dissolution of glass and small stony spherules. However, weathering alone cannot account for the high accretion rate of I-type spherules determined for two deep-sea collections. The SPWW collection provides data to constrain models of atmospheric-entry heating and to assess the effects of terrestrial weathering.

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Deep-sea spherules from Pacific clay: mass distribution and influx rate

Cited by 55 publications

References 17 publications

Cosmic spherules in the geologic record

Cosmic spherules in the geologic record

Micrometeor Observations Using the Arecibo 430 MHz Radar I. Determination of the Ballistic Parameter from Measured Doppler Velocity and Deceleration Results

Numbers, types, and compositions of an unbiased collection of cosmic spherules

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