Calcite carbonatite

Calcite carbonatites are igneous rocks that belong to the group of carbonatites . They consist of more than 50 percent by volume calcite . Calcite carbonatites can be further divided into coarse-grained sövites and medium- to fine-grained alvikites .

definition

Sövit from Magnet Cove in Arkansas, a typical calcite carbonatite

Calcite carbonatites are defined by the modal calcite content, which must be more than 50 percent by volume. The definition was first made in 1978 by Albert Fahrtisen .

mineralogy

The main mineral in calcite carbonatites is by definition calcite, which is represented with more than 50 percent by volume.

Secondary components are the carbonate anchorite , the phosphate apatite , clinopyroxene ( aegirine-augite ), biotite , magnetite and quartz , fluorite and sulphide minerals (such as pyrite , chalcopyrite and galena ), occasionally also amphibole , allanite , chlorite , melilite , monticellite, are added , Olivine , garnet (high in titanium), monazite , phlogopite , pyrochlore , titanite and wollastonite .

Post Magma table appear apatite, barite , dolomite , orthoclase , Parisit , rhodochrosite , Strontianit and Synchisit .

Chemical composition

The following table illustrates the chemical composition of calcite carbonatites:

Weight%	Average savit Amba Dongar	Phlogopit-Sövit Kaiserstuhl	Average alvikite	Alvikite Kaiserstuhl
SiO ₂	2.97	2.08	1.50	1.09
TiO ₂	0.09	0.04	0.07	0.00
Al ₂ O ₃	0.16	0.49	0.18	0.17
Fe ₂ O ₃	2.63	3.60	2.70	0.91
MnO	0.50	0.30	0.57	0.46
MgO	0.99	1.21	0.58	0.31
CaO	49.34	49.51	49.40	52.20
Na ₂ O	0.04	0.40	0.13	0.00
K ₂ O	0.06	0.51	0.08	0.00
P ₂ O ₅	1.69	1.62	0.66	1.23
CO ₂	39.76	37.06	39.85	41.10
SO ₃		2.29
BaO	0.41		0.54	0.10
SrO	0.69	1.16	0.26	0.80

Occurrence

Afghanistan
- Khanneshin
Angola :
- Bonga
Australia :
- Cummins Range
Brazil
- Jacupiranga - Hauterivian - 131 million years BP
- Serra Negra , Minas Gerais
- Topira
People's Republic of China :
- Miaoya , Hubei
Germany :
- Altvogtsburg and Schelingen in the Kaiserstuhl - 18 to 13 million years old BP - Burdigalium to Serravallian
- Laacher See
Finland :
- Siilinjärvi - Rhyacium - 2094 million years BP
- Sokli - Frasnium - 365 million years BP
India :
- Amba Dongar in Gujarat - Danium - 65.5 million years old BP
- Barra - Calymmium - 1490 million years BP
- Danta - Langera - Mahabar - Tertiary
- Kamthai
- Mahadwa - Bhagdari
- Mundwara , Rajasthan
- Munnar , Kerala
- Panwad - Kawant , Gujarat
- Samalpatti
- Sarnu - Dandali
- Sung Valley , Meghalaya - Turonian to Santonian - 90 ± 10 to 84 ± 13 million years BP
- Vinjamur
Italy :
- Monte Vulture
- Polino
Canada :
- British Columbia :
  - Aley
- Ontario :
  - Argor
  - Lackner Lake
  - Manitou Island
  - Mortinson Lake
  - Nemegosenda Lake
  - Prairie Lake
- Québec :
  - Oka carbonatite complex - Albium - 109 million years BP

Cape Verde

Brava (Santa Bárbara)

Kenya :

Malawi :

Morocco :

Tamazeght near Midelt , High Atlas

Mongolia :

Namibia :

Thick Willem - Ypresium - 49 million years BP
Kalkfeld

Norway :

Söve in the Fen area of Telemark (type locality) - Cambrian - 539 million years BP
Stjernøy

Paraguay :

Chiriguelo

Zambia :

Nkombwa Hill

Sweden :

Alnön (type locality)
Smedsgården on Alnön - Ediacarium - 560 million years old BP

South Africa :

Kruidfontein
Phalaborwa - Orosirian - 2047 million years BP
Sandhead drif

Tanzania :

Turkey :

Kizilcaşren

Uganda :

United States of America :

Arkansas :
Wyoming :
- Bear Lodge , Bear Lodge Mountains

Individual evidence

↑ Fahrtisen , A .: IUGS Subcomission on the Systematics of Igneous Rocks. Classification and nomenclature of volcanic rocks, lamprophyres, carbonatites and melilite rocks. Recommendations and suggestions. In: New Yearbook for Mineralogy . Treatises. Vol. 143. Stuttgart 1978, p. 1-14 .
↑ R. Ayuso et al: Preliminary radiogenic isotope study on the origin of the Khanneshin carbonatite complex, Helmand Province, Afghanistan . In: Journal of Geochemical Exploration . 2013.
↑ M. Santosh et al: Rare Earth Element Geochemistry of the Munnar Carbonatite, Central Kerala . In: Journal Geological Society of India . Vol. 29, 1987, pp. 335-343 .
↑ P. Kresten: Alnöområdet . Ed .: Lundqvist, T .: Beskrivning till berggrundskartan över västernorrlandslän. ser Ba 31. Sveriges geologiska undersökening, 1990, p. 238-278 .
^ GR McCormick, RC Heathcote: Mineral chemistry and petrogenesis of carbonatite intrusions . In: American Mineralogist . Vol. 72, 1987, pp. 59-66 .
^ GR McCormick, RC Heathcote: Major-cation substitution in phlogopite and evolution of carbonatites in the Potash Sulfur Springs complex, Garland County, Arkansas . In: American Mineralogist . Vol. 74, 1989, pp. 132-140 .

[1] Fahrtisen , A .: IUGS Subcomission on the Systematics of Igneous Rocks. Classification and nomenclature of volcanic rocks, lamprophyres, carbonatites and melilite rocks. Recommendations and suggestions. In: New Yearbook for Mineralogy . Treatises. Vol. 143. Stuttgart 1978, p. 1-14 .

[2] R. Ayuso et al: Preliminary radiogenic isotope study on the origin of the Khanneshin carbonatite complex, Helmand Province, Afghanistan . In: Journal of Geochemical Exploration . 2013.

[3] M. Santosh et al: Rare Earth Element Geochemistry of the Munnar Carbonatite, Central Kerala . In: Journal Geological Society of India . Vol. 29, 1987, pp. 335-343 .

[4] P. Kresten: Alnöområdet . Ed .: Lundqvist, T .: Beskrivning till berggrundskartan över västernorrlandslän. ser Ba 31. Sveriges geologiska undersökening, 1990, p. 238-278 .

[5] GR McCormick, RC Heathcote: Mineral chemistry and petrogenesis of carbonatite intrusions . In: American Mineralogist . Vol. 72, 1987, pp. 59-66 .

[6] GR McCormick, RC Heathcote: Major-cation substitution in phlogopite and evolution of carbonatites in the Potash Sulfur Springs complex, Garland County, Arkansas . In: American Mineralogist . Vol. 74, 1989, pp. 132-140 .