Development of a Circum-Arctic Chronostratigraphic Framework: Application and Refinement of the Sequence Stratigraphic Record on the North Slope of Alaska

Biostratigraphy has been a fundamental tool used to establish and apply the principles of sequence stratigraphy. Detailed chronostratigraphy has aided worldwide exploration efforts in many basins, but a comparable high resolution chronostratigraphic framework has generally been lacking for the North Slope. Detailed bio- and chronostratigraphic analyses in the North Sea and Atlantic Margin regions have resulted in the development of a robust Mesozoic and Tertiary chronostratigraphic framework which has been successfully applied to the stratigraphy of the North Slope of Alaska. Active tectonism throughout the Mesozoic and Tertiary resulted in the development of multiple unconformities and the recycling of sediment which prevented many workers from recognizing in-situ and chronostratigraphically relevant taxa. Improved datasets and quantitative analyses have shown that a detailed chronostratigraphic framework can be established for the North Slope of Alaska. A new chronostratigraphic chart has been constructed for the region.

Sequence stratigraphy modes based solely on log motif can be severely flawed particularly on tectonically active margins. Chronostratigraphic control is essential to establishing the presence of unconformity bounded sequences, and can be used to jump correlate in fault bounded basins. Quantitative biostratigraphic analysis has been used to identify regionally significant flooding surfaces in Alaska and to establish their paleobathymetric significance. Subsequently, paleobathymetric maps can be constructed for a series of time intervals on the North Slope of Alaska which aid in the interpretation of gross depositional environment (GDE). The acquisition and analyses of new quantitative biostratigraphic data would enhance the present biozonation scheme and further calibrate the circum-Arctic Mesozoic and Tertiary time scale.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California