Parental magma of the Skaergaard intrusion: constraints from melt inclusions in primitive troctolite blocks and FG-1 dykes

Jakob K. Jakobsen, Christian Tegner, C. Kent Brooks, Adam J.R. Kent, Charles E. Lesher, Troels F.D. Nielsen, Michael Wiedenbeck

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

31 Citationer (Scopus)

Abstrakt

Troctolite blocks with compositions akin to the Hidden Zone are exposed in a tholeiitic dyke cutting across the Skaergaard intrusion, East Greenland. Plagioclase in these blocks contains finely crystallised melt inclusions that we have homogenised to constrain the parental magma to 47.4-49.0 wt.% SiO2, 13.4-14.9 wt.% Al2O3 and 10.7-14.1 wt.% FeOT. These compositions are lower in FeOT and higher in SiO2 than previous estimates and have distinct La/SmN and Dy/YbN ratios that link them to the lowermost volcanic succession (Milne Land Formation) of the regional East Greenland flood basalt province. New major- and trace element compositions for the FG-1 dyke swarm, previously taken to represent Skaergaard magmas, overlap with the entire range of the regional flood basalt succession and do not form a coherent suite of Skaergaard like melts. These dykes are therefore re-interpreted as feeder dykes throughout the main phase of flood basalt volcanism.

OriginalsprogEngelsk
Sider (fra-til)61-79
Antal sider19
TidsskriftContributions to Mineralogy and Petrology
Vol/bind159
Udgave nummer1
DOI
StatusUdgivet - jan. 2010

Programområde

  • Programområde 4: Mineralske råstoffer

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