GEOSCAN, résultats de la recherche


TitreCorrelating mid-Cretaceous strata in the Canadian High Arctic using palynology
AuteurGalloway, J M; Sweet, A R; Pugh, A; Schröder-Adams, C J; Swindles, G T; Haggart, J W; Embry, A F
Source39th Annual Yellowknife Geoscience Forum, abstracts of talks and posters; par Fischer, B J; Watson, D M; Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume vol. 2011, 2011 p. 41
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120164
Réunion39th Annual Yellowknife Geoscience Forum; Yellowknife; CA; Novembre 15-17, 2011
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetsanalyses palynologiques; palynologie; palynostratigraphie; corrélation; corrélations stratigraphiques; Bassin de Sverdrup ; Formation d'Hassel ; stratigraphie; paléontologie; Crétacé
ProgrammeBassins sédimentaires de la baie de Baffin - Systèmes de pétrole dans l'Arctique canadien est (CAPSE), GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Quantitative palynological analyses undertaken on the mid-Cretaceous Hassel Formation of Sverdrup Basin and reputedly equivalent rocks from Eclipse Trough, about 850 km east, provide convincing evidence that they are coeval and of Late Albian to Cenomanian age. We base this conclusion on statistical definition of two palynomorph populations that occur in both spot samples from Eclipse Trough and in samples from Ellef Ringnes Island in the central Sverdrup Basin and correlation to previously reported palyno-assemblages from North America. By applying ordination techniques, we demonstrate that the range of variability of palynomorph composition of samples from reputed Hassel Formation in Eclipse Trough are within the range of variability defined for samples from Hassel Formation, Ellef Ringnes Island. However, because it remains unknown whether the mid-Cretaceous basin was a continuous feature linking the western and eastern Canadian Arctic regions, we continue to consider the reputed Hassel Formation of Eclipse Trough as stratigraphically and genetically distinct from the Hassel Formation of Sverdrup Basin.
Comparable proportions of dicotyledonous angiosperm pollen characterize samples from both localities, but diversity and relative abundance are lower in both of the Canadian Arctic deposits than in more southern Middle and Late Albian to Cenomanian-aged rocks of North America and macrofloral evidence of diverse angiosperm-dominated mid-Cretaceous communities in northern Alaska and northeastern Asia. To explain this, we propose that restricted angiosperm diversity and continued dominance of gymnosperms and ferns into the Cenomanian in the Canadian Arctic reflected barriers to migration, such as the Western Interior Seaway, or the existence of relatively cool continental climate conditions.