Sentences with phrase «iron pyrites»
First sulphuric acid, caused by rusting of iron pyrites in the fossils, is neutralised by ethanolamine thioglycollate, a chemical used for perming hair.
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«As bacteria ate the tissues of the animals that fell to the bottom,» he says, «they deposited a mineral called iron pyrite over the animal.
The iron pyrite then preserved the fossil.
The best idea, from Don Canfield [of the University of Southern Denmark], is that building up a little bit of atmospheric oxygen causes iron pyrite minerals in the continents to oxidize and form sulfate.
The red was rust — an oxidized form of iron pyrite, which commonly appears on local Precambrian fossil beds.
Intrigued by the ways in which iron pyrite forms natural aggregates, I began to experiment and to use cuboids to form body masses.»
A Small Visual - Voice to Celebrate the End of the Twentieth Century Machine Age, 1962/99 brass, iron pyrite, stained glass, and marble 23» x 11» x 5»
Not exact matches
The structures were exceptionally well preserved, the eggs and exoskeletons of the trilobites replaced with an iron sulfide ore called pyrite.
«Our experiments mimicking mantle conditions demonstrate that more research is needed on this pyrite - like phase of iron oxide.»
The elemental signature of these objects differed from the standard pyrite framboid, which includes iron and sulfur.
Dated to 3.43 billion years ago in sandstone from the Strelley Pool Formation in Western Australia, the microstructures were found with micrometer - sized pyrite crystals (fool's gold, an iron - sulfur mineral), as would be expected as the metabolic by - products of sulfur - based life that employ «sulphate - reduction and sulphur - disproportionation pathways.»
The results initially showed that the iron sulfide in the form of framboidal pyrite is abundant in the fine - grained fraction of this sediment.
On the seabed, dissolved iron (II) ions have combined with the hydrogen sulphide to form iron sulphides, for example pyrite, FeS2, which is unstable when the moist wood is exposed to oxygen: FeS2 (s) + 7 / 2O2 + (n +1) H2O → FeSO4 · n (H2O)(s) + H2SO4 (aq)
Commercial concentrations of gold are found in widely distributed areas: in association with ores of copper and lead, in quartz veins, in the gravel of stream beds, and with pyrites (iron sulfide).
The % TS were high in all the examined intervals and the sedimentary sulfur occurred mainly as framboidal pyrite, indicating that sufficient sulfate, indicative of seawater, was present in the deep layer of the paleo - Arctic basin and that the pyrite was formed in the sediments under sufficient iron input.
Similarly, iron which is far more abundant in the crust, thermodynamically and kinetically prefers to exist as ferric (Fe111) in our oxidising atmosphere unlike its ferrous form in the crust eg pyrite.