The System CaO-CO2-H2O and the Origin of Carbonatites

Wyllie, Peter J.; Tuttle, O. F.

doi:10.1093/petrology/1.1.1

Cited by 282 publications

(91 citation statements)

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“…"In the presence of water vapor at lkbar, calcite begins to melt at 740°C. In the system CaO+C0 2 +H 2 0 at this pressure univariant equilibria CaO+calcite+Ca(OH) 2 +liquid and calcite+Ca(OH) 2 +liquid+vapor occur at 683°C and 675°C respectively" (Wyllie and Tuttle 1960). Christidis and Triantafyllou (2007 and references therein) report the beginning of the breakdown at 640 °C for Greek limestone and marbles.…”

Section: Mineralogymentioning

confidence: 99%

¹⁴C Dating of Fire-Damaged Mortars from Medieval Finland

et al. 2012

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ABSTRACT. This study focuses on radiocarbon dating of mortars that have withstood city fires and display visible fire damage effects. Some fire-damaged and undamaged original Medieval mortars from the same site have also been tested. The mortars were heated at different temperatures and then analyzed using the same preparation procedures as in 14 C dating of mortars to see what kind of changes the heating would introduce to the mineralogy, chemistry, and the carbon and oxygen isotope ratios. We found that decarbonation during heating starts at -600 °C and recarbonation starts as soon as the temperature drops. Already after a few days, most of the lost C0 2 has been replaced with atmospheric C0 2 . The renewed carbonates are readily soluble in the acid hydrolysis process and their carbon and oxygen isotopes have a light signature. Fire-damaged historical mortars display the same features. If a long time has elapsed between hardening of the original mortar and the fire, the new carbonates have 14 C concentrations that point to the fire event rather than to the building event. In several cases, the fire-damaged mortars have an easily soluble carbonate fraction with a 14 C age that could be related to a major fire event, but still most of the soluble carbonate yields a 14 C age that seems like a reasonable age for the original construction.

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Section: Mineralogymentioning

confidence: 99%

¹⁴C Dating of Fire-Damaged Mortars from Medieval Finland

et al. 2012

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“…In the case of Uitkomst, we envisage that the parent magma to the LP was injected concurrently with the initial stages of injected along the contact between the Malmani dolomite and the Bevets conglomerate. In addition to assimilation of the roof rocks, the magma caused devolatisation of the floor dolomite, as well as partial melting facilitated by the presence of H 2 O possibly derived from pelitic interlayers (Wyllie and Tuttle 1960). Slurries of silicate and chromite crystals, together with droplets of sulphide liquid, slumped into the developing troughs which constituted efficient hydrodynamic traps.…”

Section: Magma Emplacementmentioning

confidence: 99%

The Uitkomst intrusion and Nkomati Ni-Cu-Cr-PGE deposit, South Africa: trace element geochemistry, Nd isotopes and high-precision geochronology

et al. 2017

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The Uitkomst intrusion is a tubular maficultramafic layered body that hosts one of South Africa's largest Ni-Cu-Cr-PGE deposits, Nkomati. The sulphide ore occurs in the form of massive lenses in the immediate quartzitic footwall and as disseminations within peridotite. The chromite ore forms an up to ∼10-m-thick layer in the lower portion of the intrusion. Uitkomst has generally been interpreted as a magma conduit, possibly related to the Bushveld event. Here, we present a new high-precision U-Pb zircon date of 2057.64 ± 0.69 Ma that overlaps with the age of the Merensky Reef of the Bushveld Complex and thus demonstrates a coeval relationship between the intrusions. Based on incompatible trace elements as well as O-and Nd isotope data (εNd −4.5 to −6.2), we show that the Uitkomst parent magmas were contaminated with up to 20% Archean upper crust prior to emplacement, and with up to 15% dolomitic country rock during emplacement. Ore formation at Nkomati was critically aided by substantial devolatisation and removal of dolomitic floor rocks leading to hydrodynamic concentration of sulphide and chromite during slumping of crystal mushes into the trough-like centre of the subsiding intrusion and its footwall.

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“…4d; Wyllie & Tuttle, 1960). The residual liquid must be driven toward alkali carbonates (Cooper et al, 1975), (1991), Hamilton & Kjarsgaard (1993), and Kjarsgaard et al (1995) can be more fully illustrated in terms of paths but Kjarsgaard et al (1995) pointed out that the liquids so derived do not match some definitive characteristics of crystallization in the framework of the comprehensive phase diagrams of Figs 2, 8 and 11, although the liquid of natural natrocarbonatites.…”

Section: Crystallization Paths Ofmentioning

confidence: 99%

Liquid Immiscibility in the Join NaAlSiO4--NaAlSi3O8--CaCO3 at 1 GPa: Implications for Crustal Carbonatites

Lee

Wyllie

1997

Journal of Petrology

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The System CaO-CO2-H2O and the Origin of Carbonatites

Cited by 282 publications

References 0 publications

¹⁴C Dating of Fire-Damaged Mortars from Medieval Finland

¹⁴C Dating of Fire-Damaged Mortars from Medieval Finland

The Uitkomst intrusion and Nkomati Ni-Cu-Cr-PGE deposit, South Africa: trace element geochemistry, Nd isotopes and high-precision geochronology

Liquid Immiscibility in the Join NaAlSiO4--NaAlSi3O8--CaCO3 at 1 GPa: Implications for Crustal Carbonatites

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The System CaO-CO2-H2O and the Origin of Carbonatites

Cited by 282 publications

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14C Dating of Fire-Damaged Mortars from Medieval Finland

14C Dating of Fire-Damaged Mortars from Medieval Finland

The Uitkomst intrusion and Nkomati Ni-Cu-Cr-PGE deposit, South Africa: trace element geochemistry, Nd isotopes and high-precision geochronology

Liquid Immiscibility in the Join NaAlSiO4--NaAlSi3O8--CaCO3 at 1 GPa: Implications for Crustal Carbonatites

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¹⁴C Dating of Fire-Damaged Mortars from Medieval Finland

¹⁴C Dating of Fire-Damaged Mortars from Medieval Finland