The origin and mode of emplacement of lujavrites in the Ilímaussaq alkaline complex, South Greenland☆

Sørensen, H.; Bohse, H; Bailey, J.C.

doi:10.1016/j.lithos.2006.03.021

Cited by 50 publications

(35 citation statements)

References 26 publications

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“…The units are numbered from -11 to + 16, relative to the welldeveloped marker horizon of unit 0. The layering steepens towards the margins of the intrusion and gradually disappears into a marginal pegmatite zone of the kakortokite (up to 100 m wide; Sørensen et al, 2006), ending with a sharp intrusive contact against the earlier augite syenite (Fig. 1).…”

Section: Geological Settingmentioning

confidence: 99%

Zirconosilicates in the kakortokites of the Ilímaussaq complex, South Greenland: Implications for fluid evolution and high-field-strength and rare-earth element mineralization in agpaitic systems

et al. 2016

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The layered agpaitic nepheline syenites (kakortokites) of the Ilímaussaq complex, South Greenland, host voluminous accumulations of eudialyte-group minerals (EGM). These complex Na-Ca-zirconosilicates contain economically attractive levels of Zr, Nb and rare-earth elements (REE), but have commonly undergone extensive autometasomatic/hydrothermal alteration to a variety of secondary mineral assemblages. Three EGM alteration assemblages are recognized, characterized by the secondary zirconosilicates catapleiite, zircon and gittinsite. Theoretical petrogenetic grid models are constructed to assess mineral stabilities in terms of component activities in the late-stage melts and fluids. Widespread alteration of EGM to catapleiite records an overall increase in water activity, and reflects interaction of EGM with late-magmatic Na-, Cl- and F-rich aqueous fluids at the final stages of kakortokite crystallization. Localized alteration of EGM and catapleiite to the rare Ca-Zr silicate gittinsite, previously unidentified at Ilímaussaq, requires an increase in CaO activity and suggests post-magmatic interaction with Ca-Sr bearing aqueous fluids. The pseudomorphic replacement of EGM in the kakortokites was not found to be associated with significant remobilization of the primary Zr, Nb and REE mineralization, regardless of the high concentrations of potential transporting ligands such as F and Cl. We infer that the immobile behaviour essentially reflects the neutral to basic character of the late-magmatic fluids, in which REE-F compounds are insoluble and remobilization of REE as Cl complexes is inhibited by precipitation of nacareniobsite-(Ce) and various Ca-REE silicates. A subsequent decrease in F– activity would furthermore restrict the mobility of Zr as hydroxyl-fluoride complexes, and promote precipitation of the secondary zirconosilicates within the confines of the replaced EGM domains.

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Section: Geological Settingmentioning

confidence: 99%

Zirconosilicates in the kakortokites of the Ilímaussaq complex, South Greenland: Implications for fluid evolution and high-field-strength and rare-earth element mineralization in agpaitic systems

et al. 2016

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“…2) led to the concept of the Kangerluarssuk-Lakseelv hinge-fault causing lowering of the northern part of the magma chamber by at least 600 m relative to the southern part in this area (e.g. Bohse et al, 1971;Sørensen et al, 2006b;Fig. 2), however, no exposure of this fault could be found (Bohse, personal communication).…”

Section: The Ilímaussaq Complexmentioning

confidence: 99%

Emplacement and geochemical evolution of highly evolved syenites investigated by a combined structural and geochemical field study: The lujavrites of the Ilímaussaq complex, SW Greenland

Ratschbacher

Marks

Bons

et al. 2015

Lithos

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“…1 and 2), by far the most thoroughly studied of the 12 major intrusives of the Gardar igneous province (Sørensen, 2006b), has been dated to1060 AE 5 Ma (Krumrei et al, 2006). Four intrusive phases may be distinguished in the formation of the Ilímaussaq complex (Sørensen et al, 2006). The first phase is made up of augite syenite, which is preserved only as a partial marginal shell and in the roof (Fig.…”

Section: Regional Geologymentioning

confidence: 99%

“…In their study of hydrocarbon gas inclusions hosted in quartz veins, also noted a strong fluorescence, which they attributed to the presence of higher hydrocarbons. Thus, it is likely that mixtures of hydrocarbons, both gases and higher hydrocarbons, migrated though the Sørensen et al, 2006) showing the sample locations. Full circles represent samples of the present study.…”

Section: Occurrence Of Bitumenmentioning

confidence: 99%

Bitumen biomarkers in the Mid-Proterozoic Ilímaussaq intrusion, Southwest Greenland – A challenge to the mantle gas theory

Laier

Nytoft

2012

Marine and Petroleum Geology

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The origin and mode of emplacement of lujavrites in the Ilímaussaq alkaline complex, South Greenland☆

Cited by 50 publications

References 26 publications

Zirconosilicates in the kakortokites of the Ilímaussaq complex, South Greenland: Implications for fluid evolution and high-field-strength and rare-earth element mineralization in agpaitic systems

Zirconosilicates in the kakortokites of the Ilímaussaq complex, South Greenland: Implications for fluid evolution and high-field-strength and rare-earth element mineralization in agpaitic systems

Emplacement and geochemical evolution of highly evolved syenites investigated by a combined structural and geochemical field study: The lujavrites of the Ilímaussaq complex, SW Greenland

Bitumen biomarkers in the Mid-Proterozoic Ilímaussaq intrusion, Southwest Greenland – A challenge to the mantle gas theory

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