Matches in SemOpenAlex for { <https://semopenalex.org/work/W29737582> ?p ?o ?g. }
Showing items 1 to 63 of
63
with 100 items per page.
- W29737582 abstract "The dykes from the Igaliko Nepheline Syenite complex belong to at least 3 individual swarms (i) a Mid-Gardar swarm in the Ostfjordsdal valley, (ii) a Late-Gardar, Si-oversaturated swarm associated with the Younger Giant Dykes of Tugtutoq and (iii) a Si-undersaturated swarm intimately associated with the Late Gardar Igaliko Nepheline Syenite Central Complexes. In addition Early Gardar activity is recorded by the presence of some ultramafic lamprophyres which predate the Motzfeldt centre, sparse trachytes which are truncated by intrusions within the Motzfeldt centre and a possible BD(_0) dolerite which is also cut by the Motzfeldt centre. Most dykes however are bracketed between the Early and Late Igdlerfigssalik syenite intrusions. The main oversaturated and undersaturated suites can be separated on their Zr/Nb ratios (≈6.4 and 3.9 respectively). In addition, the undersaturated basic rocks have smooth chondrite normalised incompatible element spidergrams whereas the oversaturated basic rocks are characterised by negative Nb and positive P anomalies. Evolution of both suites can be modelled in terms of fractional crystallisation of feldspar, clinopyroxene, olivine, apatite and opaques from basaltic parents to either phonolitic or rhyolitic minimum compositions. In each instance these evolved composi tions are extremely rich in incompatible trace elements (REE, Nb, Zr, Rb). In some cases a high CO(_2) content in the undersaturated rocks may lead to the formation (by liquid immiscibility) of late stage carbonatite magmas. High CO(_2) also produces high ƒo(_2) in these magmas and it is argued that in some cases this can suppress the development of negative Eu anomalies on feldspar fractionation. The undersaturated swarm may have evolved from lamprophyric parental magmas, eg. camptonites, which are relatively abundant basic dykes. Ultramafic lamprophyres, often early, may have formed as extremely small degree partial melts at the onset of Gardar rifting. In the Late Gardar, magma genesis is related to the different extensional tectonic regimes which were operative at that time. Mineralogical evolution follows paths similar to several other Gardar suites and records a higher ƒo(_2) in the undersaturated rocks. Zr becomes concentrated in interstitial residual liquids in benmoreites and substitutes into amphibole as the newly proposed end-member zirconian-arfvedsonite." @default.
- W29737582 created "2016-06-24" @default.
- W29737582 creator A5007521759 @default.
- W29737582 date "1988-01-01" @default.
- W29737582 modified "2023-09-26" @default.
- W29737582 title "The petrology and geochemistry of the Igaliko Dyke swarm, south Greenland." @default.
- W29737582 hasPublicationYear "1988" @default.
- W29737582 type Work @default.
- W29737582 sameAs 29737582 @default.
- W29737582 citedByCount "3" @default.
- W29737582 crossrefType "dissertation" @default.
- W29737582 hasAuthorship W29737582A5007521759 @default.
- W29737582 hasConcept C11872896 @default.
- W29737582 hasConcept C127313418 @default.
- W29737582 hasConcept C140441402 @default.
- W29737582 hasConcept C161509811 @default.
- W29737582 hasConcept C17409809 @default.
- W29737582 hasConcept C2778849375 @default.
- W29737582 hasConcept C2779289598 @default.
- W29737582 hasConcept C2780981397 @default.
- W29737582 hasConcept C2910463356 @default.
- W29737582 hasConcept C44938399 @default.
- W29737582 hasConcept C5900021 @default.
- W29737582 hasConcept C67236022 @default.
- W29737582 hasConceptScore W29737582C11872896 @default.
- W29737582 hasConceptScore W29737582C127313418 @default.
- W29737582 hasConceptScore W29737582C140441402 @default.
- W29737582 hasConceptScore W29737582C161509811 @default.
- W29737582 hasConceptScore W29737582C17409809 @default.
- W29737582 hasConceptScore W29737582C2778849375 @default.
- W29737582 hasConceptScore W29737582C2779289598 @default.
- W29737582 hasConceptScore W29737582C2780981397 @default.
- W29737582 hasConceptScore W29737582C2910463356 @default.
- W29737582 hasConceptScore W29737582C44938399 @default.
- W29737582 hasConceptScore W29737582C5900021 @default.
- W29737582 hasConceptScore W29737582C67236022 @default.
- W29737582 hasLocation W297375821 @default.
- W29737582 hasOpenAccess W29737582 @default.
- W29737582 hasPrimaryLocation W297375821 @default.
- W29737582 hasRelatedWork W1996684680 @default.
- W29737582 hasRelatedWork W2017458605 @default.
- W29737582 hasRelatedWork W2027262466 @default.
- W29737582 hasRelatedWork W2034227965 @default.
- W29737582 hasRelatedWork W2051348095 @default.
- W29737582 hasRelatedWork W2054615175 @default.
- W29737582 hasRelatedWork W2080424264 @default.
- W29737582 hasRelatedWork W2106837803 @default.
- W29737582 hasRelatedWork W2126559808 @default.
- W29737582 hasRelatedWork W2137335623 @default.
- W29737582 hasRelatedWork W2139023853 @default.
- W29737582 hasRelatedWork W2150273205 @default.
- W29737582 hasRelatedWork W2300194048 @default.
- W29737582 hasRelatedWork W2332599345 @default.
- W29737582 hasRelatedWork W2614672254 @default.
- W29737582 hasRelatedWork W2780478187 @default.
- W29737582 hasRelatedWork W3023492021 @default.
- W29737582 hasRelatedWork W3166471557 @default.
- W29737582 hasRelatedWork W3167036956 @default.
- W29737582 hasRelatedWork W651694141 @default.
- W29737582 isParatext "false" @default.
- W29737582 isRetracted "false" @default.
- W29737582 magId "29737582" @default.
- W29737582 workType "dissertation" @default.