Characteristics and mass distribution of extraterrestrial dust from the Greenland ice cap

Maurette, M.; Jèhanno, C.; Robin, Éric; Hammer, C. U.

doi:10.1038/328699a0

Cited by 128 publications

(87 citation statements)

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“…For these two reasons, a volcanic cause for the dark region seems unlikely. As the REE patterns for the different sites reveal a source with a chemical composition similar to the upper continental crust, the material does not seem to contain micrometeorites, which have been found on the Greenland ice sheet (Maurette et al, 1987). This is confirmed by our microscopic analyses.…”

Section: Discussionsupporting

confidence: 74%

Dust from the dark region in the western ablation zone of the Greenland ice sheet

et al. 2011

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Abstract.A dark region tens of kilometres wide is located in the western ablation zone of the Greenland ice sheet. The dark appearance is caused by higher amounts of dust relative to the brighter surroundings. This dust has either been deposited recently or was brought to the surface by melting of outcropping ice. Because the resulting lower albedos may have a significant effect on melt rates, we analysed surface dust on the ice, also called cryoconite, from locations in the dark region as well as locations from the brighter surrounding reference ice with microscopic and geochemical techniques to unravel its composition and origin. We find that (part of) the material is derived from the outcropping ice, and that there is little difference between dust from the dark region and from the reference ice. The dust from the dark region seems enriched in trace and minor elements that are mainly present in the current atmosphere because of anthropogenic activity. This enrichment is probably caused by higher precipitation and lower melt rates in the dark region relative to the ice marginal zone. The rare earth elemental ratios of the investigated material are approximately the same for all sites and resemble Earth's average crust composition. Therefore, the cryoconite probably does not contain volcanic material. The mineralogical composition of the dust excludes Asian deserts, which are often found as provenance for glacial dust in ice cores, as source regions. Consequently, the outcropping dust likely has a more local origin. Finally, we find cyanobacteria and algae in the cryoconite. Total Organic Carbon accounts for up to 5 weight per cent Correspondence to: I. G. M. Wientjes (i.g.m.wientjes@uu.nl) of the cryoconite from the dark region, whereas dust samples from the reference ice contain only 1 % or less. This organic material is likely formed in situ. Because of their high light absorbency, cyanobacteria and the organic material they produce contribute significantly to the low albedo of the dark region.

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Section: Discussionsupporting

confidence: 74%

Dust from the dark region in the western ablation zone of the Greenland ice sheet

et al. 2011

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“…Nickel-isotopic analysis of I-type spherules from the DSS show that Ni is mass fractionated with Ni loss ranging 36-95% (Xue et al, 1995). The rare, unmelted metal grains described by Maurette et al (1987) may be the unmelted precursor of I-type spherules. Note that I-type spherules account for only 2% of the SPWW collection, a value similar to the 7% found for iron meteorite falls (McSween, 1987).…”

Section: Effects Of Atmospheric Heatingmentioning

confidence: 99%

“…Maurette and his colleagues found that unmelted micrometeorites constitute 32% of their Greenland samples (Maurette et al, 1987) and 40% of their Cap Prudhomme samples (Maurette et al, 1991) averaged across all size fractions. Michel Maurette kindly sorted, particle by particle, a small (0.1 g) sample of the SPWW 106-250 p m size fraction.…”

Section: Unmelted Micrometeoritesmentioning

confidence: 99%

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

Taylor

Lever

Harvey

2000

Meteorit & Planetary Scien

177

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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“…The primary source of information about the composition and morphology of IDPs are the 36 large collections of micrometeorites retrieved in the stratosphere (Rietmeijer, 2000, 37 Zolensky and Lindstrom, 1992), the ice caps (Maurette, et al, 1987, Taylor, et al, 1998, 38 deserts (Kohout, et al, 2014) and deep sea sediments (Blanchard, et al, 1980). While these 39 collections include particles exhibiting different degrees of thermal alteration (ranging from 40 unmelted particles to cosmic spherules) and weathering, it has been possible to establish 41 their general properties before aerobraking (Jessberger, et al, 2001, Kohout, et al, 2014, 42 Taylor, et al, 2012.…”

Section: Composition Morphology and Size Distribution Of Interplanetmentioning

confidence: 99%

Prognostic Value of Cardiovascular Magnetic Resonance and Single-Photon Emission Computed Tomography in Suspected Coronary Heart Disease: Long-Term Follow-up of a Prospective, Diagnostic Accuracy Cohort Study

et al. 2016

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11Analogues have been developed and characterised for both interplanetary dust and 12 meteoric smoke particles. These include amorphous materials with elemental compositions 13 similar to the olivine mineral solid solution series, a variety of iron oxides, undifferentiated 14 meteorites (chondrites) and minerals which can be considered good terrestrial proxies to 15 some phases present in meteorites. The products have been subjected to a suite of 16 analytical techniques to demonstrate their suitability as analogues for the target materials. 17

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Characteristics and mass distribution of extraterrestrial dust from the Greenland ice cap

Cited by 128 publications

References 0 publications

Dust from the dark region in the western ablation zone of the Greenland ice sheet

Dust from the dark region in the western ablation zone of the Greenland ice sheet

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

Prognostic Value of Cardiovascular Magnetic Resonance and Single-Photon Emission Computed Tomography in Suspected Coronary Heart Disease: Long-Term Follow-up of a Prospective, Diagnostic Accuracy Cohort Study

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