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Ankerite

About: Ankerite is a research topic. Over the lifetime, 859 publications have been published within this topic receiving 23960 citations.


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Journal ArticleDOI
TL;DR: The new data suggest that PO2 rose dramatically from about 1 percent PAL (present atmospheric level) to > or = 15 percent PAL between 2.2 and 1.2 bybp but is consistent with the highly oxidized nature of the 1.85 by Flin Flon paleosol.
Abstract: A core drilled near Wolhaarkop in Griqualand West, South Africa, intersected highly oxidized Kuruman Iron Formation below red beds of the Gamagara Formation. The lateral equivalents of the Kuruman Iron Formation in this drill hole consist largely of siderite, ankerite, magnetite, greenalite, and quartz. The oxidation of the Kuruman Iron Formation in WOL 2 occurred almost certainly during weathering prior to the deposition of the Gamagara Formation. The date of this weathering episode is bracketed between about 2.2 and 1.9 bybp by the age of the Ongeluk lavas in the Transvaal sequence below the unconformity and by the age of the Hartley lavas in the Olifantshoek Group above the unconformity. The ratio of iron to SiO2 in the several facies of the weathered Kuruman Iron Formation in WOL 2 is nearly the same as that in their unweathered equivalents. Since SiO2 loss during weathering was almost certainly minor, the similarity of the Fe/SiO2 ratio in the weathered and unweathered BIF indicates that nearly all the "FeO" in the Kuruman Iron Formation was oxidized and retained as FeO3 during weathering. Such a high degree of iron retention is best explained by an O2 content of the atmosphere > or = 0.03 atm at the time of weathering. Such an O2 pressure is very much greater than that suggested by the composition of paleosols developed on basalt > or = 2.2 bybp but is consistent with the highly oxidized nature of the 1.85 by Flin Flon paleosol. The new data suggest that PO2 rose dramatically from about 1 percent PAL (present atmospheric level) to > or = 15 percent PAL between 2.2 and 1.9 bybp.

236 citations

Journal ArticleDOI
TL;DR: The No. 6 coal from the Guanbanwusu Mine, Jungar Coalfield, Inner Mongolia, the authors has a low rank (Ro,ran = 0.56%) and a low-sulfur content (St,d ǫ= 0.58%) and the proportion of inertinite in the coal is higher than that of vitrinite (31%).

235 citations

Journal ArticleDOI
01 Oct 2003-Fuel
TL;DR: The phase-mineral and chemical composition of feed coals and their fly ashes (FAs) produced in four large Spanish thermo-electric power stations was characterized as a basis for multicomponent FA utilization as mentioned in this paper.

219 citations

Journal ArticleDOI
TL;DR: Oxygen isotope ratios were determined for quartz, magnetite, ankerite, siderite, riebeckite, hematite and talc in samples of banded iron-formation from the Dales Gorge Member of the Brockman Iron Formation.

218 citations

Journal ArticleDOI
TL;DR: The first discovery and sampling of vast fields of hydrocarbon-derived carbonate chimneys along the Gulf of Cadiz continental slope, at depths between 500 and 1200 m, was reported in this paper.

217 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202332
202270
202140
202027
201946
201842