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INTEGRATED PALEOPEDOLOGY AND PALYNOLOGY FROM ALLUVIAL
PALEOSOLS OF THE CRETACEOUS (CENOMANIAN) DUNVEGAN
FORMATION, ALBERTA AND BRITISH COLUMBIA, CANADA:
PALEOENVIRONMENTAL AND STRATIGRAPHIC IMPLICATIONS
JACOB R. MONGRAIN* AND PAUL J. MCCARTHY
Department of Geology & Geophysics, and Geophysical Institute, University of Alaska,
Fairbanks, Alaska 99775-5780, USA
*Present address: Shell Exploration and Production Company, Houston,
Texas 77079-1115, USA
e-mail: Jacob.Mongrain@shell.com
A. GUY PLINT
Department of Earth Sciences, The University of Western Ontario, London,
Ontario, N6A 5B7, Canada
AND
SARAH J. FOWELL
Department of Geology & Geophysics, University of Alaska, Fairbanks,
Alaska 99775-5780, USA
ABSTRACT: The Dunvegan Formation is a mid-Cretaceous alluvial plain–deltaic deposit exposed along
the Rocky Mountain Foothills and Peace River Valley of Alberta and British Columbia, Canada. A
multiproxy approach, combining paleosol micromorphology, geochemistry, and mineralogy with
palynology, is used to reconstruct the climatic, pedogenic, and depositional history of this high-latitude
setting during a greenhouse climate regime. Intrinsic features of paleosols within the Dunvegan
Formation suggest a warm to cool temperate paleoclimate. These paleosols experienced multiple
depositional phases superimposed on pedogenic phases that resulted in complicated compound, complex,
and welded paleosol profiles. Well-preserved palynomorph assemblages within the paleosols are
composed primarily of fern spores, with small percentages of gymnosperm pollen. The palynomorphs
suggest a humid paleoclimate ranging from cool temperate to subtropical. The abundance of fern spores
in all of the paleosol profiles suggests early successional colonization of the floodplain. Better-developed
interfluve paleosols contain greater percentages of tree pollen, indicating the presence of nearby forests.
Within interfluve paleosols, intervals barren of pollen coincide with sequence boundaries identified on the
basis of micromorphology and geochemistry. Our combined paleopedological and palynological data sets,
together with macrofloral and geochemical paleoclimate indicators, suggest that the Dunvegan alluvial–
coastal plain complex probably formed under a humid, warm to cool temperate paleoclimate with a mean
annual temperature (MAT) between 12 and 14° C and mean annual precipitation (MAP) between 1200
and 1300 mm yr -1 . These integrated data sets also provide a better understanding of the stratigraphic
development of the coastal plains.