Reconstructing a Mid-Cretaceous Landscape From Paleosols In Western Canada
Geography and Geology
The Albian Stage of the mid-Cretaceous was a time of equable climate conditions with high sea levels and broad shallow epeiric seas that may have had a moderating affect on continental climates. A Late Albian landscape surface that developed during a regression and subsequent sea-level rise in the Western Canada Foreland Basin is reconstructed on the basis of correlation of paleosols penetrated by cores through the Paddy Member of the Peace River Formation. Reconstruction of this landscape refines chronostratigraphic relationships and will benefit future paleoclimatological studies utilizing continental sphaerosiderite proxy records. The paleosols developed in estuarine sandstones and mudstones, and they exhibit evidence of a polygenetic history. Upon initial exposure and pedogenesis, the Paddy Member developed deeply weathered, well-drained cumulative soil profiles. Later stages of pedogenesis were characterized, by hydromorphic soil conditions. The stages of soil development interpreted for the Paddy Member correlate with inferred stages of pedogenic development in timeequivalent formations located both basinward and downslope (upper Viking Formation), and landward and upslope (Boulder Creek Formation). On the basis of the genetic similarity among paleosols in these three correlative formations, the paleosols are interpreted as having formed along a single, continuous landscape surface. Results of this study indicate that the catena concept of pedogenesis along sloping landscapes is applicable to ancient successions. Sphaerosiderites; in the Paddy Member paleosols are used to provide proxy values for meteoric delta(18)O values at 52 degrees N paleolatitude in the Cretaceous Western Interior Basin. The meteoric delta(18)O values are used to refine existing interpretations about the mid-Cretaceous paleolatitudinal gradient in meteoric delta(18)O values, and the mid-Cretaceous hydrologic cycle.
Journal of Sedimentary Research
Ufnar, D. F.,
González, L. A.,
Ludvigson, G. A.,
Brenner, R. L.,
Witzke, B. J.,
(2005). Reconstructing a Mid-Cretaceous Landscape From Paleosols In Western Canada. Journal of Sedimentary Research, 75(6), 984-996.
Available at: http://aquila.usm.edu/fac_pubs/2619