Open AccessThe age of the Kap Washington Group volcanics, North Greenland
Author(s) -
Ole Larsen
Publication year - 1982
Publication title -
bulletin of the geological society of denmark
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.674
H-Index - 28
eISSN - 2245-7070
pISSN - 0011-6297
DOI - 10.37570/bgsd-1982-31-04
Subject(s) - geology , rhyolite , peralkaline rock , volcanic rock , rift , extrusive , volcano , cretaceous , geochemistry , group (periodic table) , paleontology , structural basin , chemistry , organic chemistry
The Kap Washington Group of peralkaline volcanics is exposed along the coast of North Greenland at 40°W. This coastal region is intruded by numerous NNE-NW-trending dolerite dykes of alkaline affinity. The volcanics and their basic intrusive counterparts appear to be related to the initial rifting in the Arctic Ocean basin. The timing of this rifting may be supported by accurate dating of the associated volcanic activity. An improved Rb/Sr age of 64±3 million years (i.e. approximately at the Cretaceous-Tertiary boundary) has been determined on rhyolitic lavas collected at Kap Kane, probably near the top of the volcanic sequence. The extrusive volcanic activity probably started already in late Cretaceous time, as indicated by fossil plant remains, found in sediments interbedded with the lavas on Lockwood 0.