Correlating middle Cretaceous palynological records from the Canadian High Arctic based on a section from the Sverdrup Basin and samples from the Eclipse Trough

Abstract

Quantitative palynological analyses undertaken on the middle Cretaceous Hassel Formation of the Sverdrup Basin and reputedly equivalent rocks from the Eclipse Trough, about 850 km east, provide convincing evidence that they are coeval and of Late Albian–Cenomanian age. We base this conclusion on statistical definition of two palynomorph populations that occur in both spot samples from the Eclipse Trough and in samples from a measured section at Hoodoo Dome, Ellef Ringnes Island in the central Sverdrup Basin, which demonstrate a broad correlation to previously reported palynofloras from North America. By applying ordination techniques, we demonstrate that the range of variability of palynomorph composition of samples from the reputed Hassel Formation in the Eclipse Trough are within the range of variability defined for samples from the Hassel Formation, Hoodoo Dome. 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–Cenomanian-aged rocks of North America. To explain this, we propose that restricted angiosperm diversity and continued dominance of gymnosperms and ferns into the Cenomanian in the Canadian Arctic reflect relatively cool continental climate conditions or barriers to migration, such as the Western Interior Seaway.

Keywords:

• Cretaceous
• Eclipse Trough
• Hassel Formation
• pollen and spores
• Sverdrup Basin; Arctic

Acknowledgements

The authors wish to acknowledge the logistic support of the Polar Continental Shelf Project. Financial support was provided by the GeoMapping for Energy and Minerals Program (Geological Survey of Canada), a National Science and Engineering Research Council Visiting Fellow in a Canadian Government Laboratory award to JMG. CSA is funded by the National Science and Engineering Research Council and ConocoPhillips. The late Hans Wielens, formerly of the Geological Survey of Canada (GSC)-Dartmouth, and Andrew Arreak, Pond Inlet, Nunavut, helped with collection of field samples from the Eclipse Trough. Rick Fontaine, GSC-Calgary, located archival samples collected by HR Balkwill from the Eclipse Trough in GSC holdings. Linda Dancey, also of GSC-Calgary, prepared all palynological samples. Jared Fath provided drafting assistance with the help of Dr Lisel Currie. Drs Graham L. Williams and Robert A. Fensome (both of GSC-Atlantic, Dartmouth) provided constructive comments that greatly improved this manuscript.