ABSTRACT: Palynology as a Tool for the Recognition of Parasequence Sets in a Shaly Section: The Kanguk Formation (Upper Cretaceous), Canadian Arctic

NUNEZ-BETELU, L. KOLDO, and L. V. HILLS, University of Calgary, Calgary, Alberta, Canada

A palynological research technique is proposed herein as a biostratigraphic tool for the study of shaly sections and their positioning within sequence-stratigraphic reconstruction models. The section to be studied must be systematically sampled at closely spaced regular intervals to establish a good control on introduction levels of taxa. Detailed counting and statistical analysis, mainly utilizing terrestrial to marine palynomorph ratios, permit establishment of variations in assemblages that reflect changes in the degree of marine influence on them.

Based on this technique, a parasequence set was recognized within a lithologically uniform shaly section of the Kanguk Formation on Remus Creek (Ellesmere Island). The section is about 39 m thick and ranges from late Turonian to early Campanian in age. In the lower part of the section, palynomorphs are arranged in three cycles with bases marked by characteristic marine assemblages and by an abrupt influx of dinocysts and acritarchs that progressively decrease to be replaced by thin-walled miospores. Each one of these cycles represents a parasequence bounded by marine-flooding surfaces and, thus, cyclicity indicates transgressive-regressive events not recorded in the lithology. In the upper interval, poorly preserved marine palynomorphs are still present but terrestrial palynomorphs be ome dominant and no cyclicity is observed.

Based on the palynological content the Remus Creek section of the Kanguk Formation might be interpreted as a condensed section occurring within a transgressive-system tract.

In summary, the technique may be applied to obtain changes in the relative degree of distance to shoreline and, thus, to the recognition of sequence-stratigraphic patterns and to the sequence stratigraphic problem of relating unconformable sequences to conformable sequences within the basin.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)