Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria
The early augite syenite unit in the 1·13-Ga-old Il i ´ maussaq intrusive complex, South Greenland, consists of a magmatic assemblage of ternary alkali feldspar + fayalitic olivine + augite + titanomagnetite + apatite + baddeleyite ± nepheline ± quartz ± ilmenite ± zircon. Feldspar, nepheline and QU...
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fthighwire:oai:open-archive.highwire.org:petrology:42/10/1947 2023-05-15T16:27:58+02:00 Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria MARKS, MICHAEL MARKL, GREGOR 2001-10-01 00:00:00.0 text/html http://petrology.oxfordjournals.org/cgi/content/short/42/10/1947 https://doi.org/10.1093/petrology/42.10.1947 en eng Oxford University Press http://petrology.oxfordjournals.org/cgi/content/short/42/10/1947 http://dx.doi.org/10.1093/petrology/42.10.1947 Copyright (C) 2001, Oxford University Press ARTICLES TEXT 2001 fthighwire https://doi.org/10.1093/petrology/42.10.1947 2015-02-28T20:43:49Z The early augite syenite unit in the 1·13-Ga-old Il i ´ maussaq intrusive complex, South Greenland, consists of a magmatic assemblage of ternary alkali feldspar + fayalitic olivine + augite + titanomagnetite + apatite + baddeleyite ± nepheline ± quartz ± ilmenite ± zircon. Feldspar, nepheline and QUILF thermometry yield <rm>T</rm> = 1000–700°C, at <rm>P</rm> = 1 kbar, which is derived from fluid inclusion data from other parts of the complex. Ternary feldspar was the first major liquidus phase. It crystallized at temperatures between 950 and 1000°C from a homogeneous magma with <rm>a</rm> SiO 2 = 0·8 and <rm>f</rm> O 2 about 1·5–2 log units below the fayalite–magnetite–quartz (FMQ) buffer. Later, closed system fractionation produced nepheline-bearing assemblages with <rm>a</rm> SiO 2 = 0·4 and log <rm>f</rm> O 2 = FMQ – 3 to FMQ – 5. Assimilation of wall rocks produced local variations of melt composition. Four traverses through the unit were sampled parallel to the assumed direction of crystallization. They exhibit significant differences in their mineral assemblages and compositions. The chemical zoning and calculated intensive parameters of four sample suites reflect both closed system fractional crystallization and local assimilation of wall rocks. Text Greenland HighWire Press (Stanford University) Greenland Ilimaussaq ENVELOPE(-45.900,-45.900,60.983,60.983) Wall Rocks ENVELOPE(-129.312,-129.312,52.728,52.728) Journal of Petrology 42 10 1947 1969 |
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HighWire Press (Stanford University) |
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fthighwire |
language |
English |
topic |
ARTICLES |
spellingShingle |
ARTICLES MARKS, MICHAEL MARKL, GREGOR Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria |
topic_facet |
ARTICLES |
description |
The early augite syenite unit in the 1·13-Ga-old Il i ´ maussaq intrusive complex, South Greenland, consists of a magmatic assemblage of ternary alkali feldspar + fayalitic olivine + augite + titanomagnetite + apatite + baddeleyite ± nepheline ± quartz ± ilmenite ± zircon. Feldspar, nepheline and QUILF thermometry yield <rm>T</rm> = 1000–700°C, at <rm>P</rm> = 1 kbar, which is derived from fluid inclusion data from other parts of the complex. Ternary feldspar was the first major liquidus phase. It crystallized at temperatures between 950 and 1000°C from a homogeneous magma with <rm>a</rm> SiO 2 = 0·8 and <rm>f</rm> O 2 about 1·5–2 log units below the fayalite–magnetite–quartz (FMQ) buffer. Later, closed system fractionation produced nepheline-bearing assemblages with <rm>a</rm> SiO 2 = 0·4 and log <rm>f</rm> O 2 = FMQ – 3 to FMQ – 5. Assimilation of wall rocks produced local variations of melt composition. Four traverses through the unit were sampled parallel to the assumed direction of crystallization. They exhibit significant differences in their mineral assemblages and compositions. The chemical zoning and calculated intensive parameters of four sample suites reflect both closed system fractional crystallization and local assimilation of wall rocks. |
format |
Text |
author |
MARKS, MICHAEL MARKL, GREGOR |
author_facet |
MARKS, MICHAEL MARKL, GREGOR |
author_sort |
MARKS, MICHAEL |
title |
Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria |
title_short |
Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria |
title_full |
Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria |
title_fullStr |
Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria |
title_full_unstemmed |
Fractionation and Assimilation Processes in the Alkaline Augite Syenite Unit of the Ilimaussaq Intrusion, South Greenland, as Deduced from Phase Equilibria |
title_sort |
fractionation and assimilation processes in the alkaline augite syenite unit of the ilimaussaq intrusion, south greenland, as deduced from phase equilibria |
publisher |
Oxford University Press |
publishDate |
2001 |
url |
http://petrology.oxfordjournals.org/cgi/content/short/42/10/1947 https://doi.org/10.1093/petrology/42.10.1947 |
long_lat |
ENVELOPE(-45.900,-45.900,60.983,60.983) ENVELOPE(-129.312,-129.312,52.728,52.728) |
geographic |
Greenland Ilimaussaq Wall Rocks |
geographic_facet |
Greenland Ilimaussaq Wall Rocks |
genre |
Greenland |
genre_facet |
Greenland |
op_relation |
http://petrology.oxfordjournals.org/cgi/content/short/42/10/1947 http://dx.doi.org/10.1093/petrology/42.10.1947 |
op_rights |
Copyright (C) 2001, Oxford University Press |
op_doi |
https://doi.org/10.1093/petrology/42.10.1947 |
container_title |
Journal of Petrology |
container_volume |
42 |
container_issue |
10 |
container_start_page |
1947 |
op_container_end_page |
1969 |
_version_ |
1766017577653370880 |