Integrated High-Resolution Cretaceous Stratigraphy & Basin Analysis

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Approximately one hundred million year old Cretaceous rocks beneath the Plains of western Canada are globally-significant because they provide one of the most complete records of Cretaceous climate and sea-level change. Abundant records from oil and gas boreholes allow us to map rock layers in great detail, reconstructing ancient shorelines, rivers, deltas and flood- plains. One of the most interesting results coming from our mapping is that sea-level oscillated up and down by perhaps 5-20 m on time-scales of about 20,000 to 400,000 yrs. Such changes are most logically attributed to the growth and melting of modest ice-caps on the Antarctic continent. This however is contrary to the popular conception of the Cretaceous climate as being a 'greenhouse', ice-free world with very high atmospheric CO2 levels. Our results from western Canada have led us to collaborate with scientists in Canada, the UK, US, Czech Republic and Poland to study paleoclimate, high-precision radiometric dating, biostratigraphic and sequence-stratigraphic correlation in an attempt to demonstrate that sea-level changes observed in Canada are of global extent, - proof of which would greatly strengthen the argument for waxing and waning Antarctic ice caps, and cause serious re-thinking of the nature of the 'Cretaceous greenhouse'.