U–Pb geochronology of the Eocene Kærven intrusive complex, East Greenland: constraints on the Iceland hotspot track during the rift-to-drift transition
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U–Pb geochronology of the Eocene Kærven intrusive complex, East Greenland : constraints on the Iceland hotspot track during the rift-to-drift transition. / Þórarinsson, Sigurjón Böðvar; Holm, Paul Martin; Tappe, Sebatstian; Heaman, Larry M.
I: Geological Magazine, Bind 153, Nr. 1, 2016, s. 128-142.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - U–Pb geochronology of the Eocene Kærven intrusive complex, East Greenland
T2 - constraints on the Iceland hotspot track during the rift-to-drift transition
AU - Þórarinsson, Sigurjón Böðvar
AU - Holm, Paul Martin
AU - Tappe, Sebatstian
AU - Heaman, Larry M.
PY - 2016
Y1 - 2016
N2 - Several major tholeiitic (e.g. the Skaergaard intrusion) and alkaline (e.g. the Kangerlussuaq Syenite) intrusive complexes of the North Atlantic Large Igneous Province are exposed along the Kangerlussuaq Fjord in East Greenland. The Kærven Complex forms a satellite intrusion to the Kangerlussuaq Syenite and includes early tholeiitic gabbros and a series of cross-cutting alkaline intrusions ranging from monzonite to alkali granite. The alkaline intrusions cut the gabbros, and are cut by the outer nordmarkite zone of the Kangerlussuaq Syenite. This study presents the first U–Pb zircon ages from the alkaline units of the Kærven Complex. Fourteen multi-grain zircon fractions have been analysed by thermal ionization mass spectrometry (TIMS). Absolute age differences could not be resolved between the different units, suggesting a relatively rapid succession of intrusions between c. 53.5 and 53.3 Ma. Our compilation of precise radiometric age data shows that most of the alkaline magmatism in the Kangerlussuaq Fjord occurred prior to 50 Ma. Moreover, pre-50 Ma alkaline intrusions and lavas show a SSE-younging trend, which is interpreted as the track of the Iceland hotspot during the rift-to-drift transition of the North Atlantic.
AB - Several major tholeiitic (e.g. the Skaergaard intrusion) and alkaline (e.g. the Kangerlussuaq Syenite) intrusive complexes of the North Atlantic Large Igneous Province are exposed along the Kangerlussuaq Fjord in East Greenland. The Kærven Complex forms a satellite intrusion to the Kangerlussuaq Syenite and includes early tholeiitic gabbros and a series of cross-cutting alkaline intrusions ranging from monzonite to alkali granite. The alkaline intrusions cut the gabbros, and are cut by the outer nordmarkite zone of the Kangerlussuaq Syenite. This study presents the first U–Pb zircon ages from the alkaline units of the Kærven Complex. Fourteen multi-grain zircon fractions have been analysed by thermal ionization mass spectrometry (TIMS). Absolute age differences could not be resolved between the different units, suggesting a relatively rapid succession of intrusions between c. 53.5 and 53.3 Ma. Our compilation of precise radiometric age data shows that most of the alkaline magmatism in the Kangerlussuaq Fjord occurred prior to 50 Ma. Moreover, pre-50 Ma alkaline intrusions and lavas show a SSE-younging trend, which is interpreted as the track of the Iceland hotspot during the rift-to-drift transition of the North Atlantic.
U2 - 10.1017/S0016756815000448
DO - 10.1017/S0016756815000448
M3 - Journal article
VL - 153
SP - 128
EP - 142
JO - Geological Magazine
JF - Geological Magazine
SN - 0016-7568
IS - 1
ER -
ID: 122776246