--> Abstract: Low Energy Alluvial Deposits from the Upper Cretaceous Prince Creek Formation, National Petroleum Reserve, North Slope, Alaska; #90063 (2007)

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Low Energy Alluvial Deposits from the Upper Cretaceous Prince Creek Formation, National Petroleum Reserve, North Slope, Alaska

 

Flaig, Peter P.1, Paul J. McCarthy2, Erik Brandlen1, Anthony R. Fiorillo3 (1) University of Alaska-Fairbanks, Fairbanks, AK (2) University of Alaska, Fairbanks, AK (3) Museum of Nature and Science, Dallas,

 

The Upper Cretaceous Prince Creek Formation crops out along the Colville River within the National Petroleum Reserve, North Slope, Alaska, and records a non-marine succession of predominantly low energy stream and associated flood-plain deposits. Overbank mudstones and siltstones contain root traces, drab colors, blocky structure, siderite nodules, and Fe-oxide mottling as well as rare dinosaur bones. Thin sheet sandstones up to 0.5 m thick also occur within floodplain deposits. These non-channelized floodplain facies are interpreted as lakes, lake margins, peat-bogs, levees, and crevasse splays. Poorly drained and weakly developed cumulative paleosols are ubiquitous within this low-lying alluvial plain.

 

Most channel sandbodies are 1 to 3 m thick, single story, very fine-to fine-grained, trough cross-laminated and/or rippled, and frequently contain carbonized root traces and siderite concretions. Finer-grained sandbodies occur either as small, thin, ribbon-like channels surrounded by overbank fines, or as more extensive sheet-like sands with lateral accretion surfaces. Ribbon sandbodies are interpreted as non-migrating anastomosed channel fills while sheet sandbodies display a more meandering character.

 

Rare, multi-story medium-to coarse-grained sheet sandstones up to 7 m thick are also present within the Prince Creek Formation. Coarser-grained sandbodies are dominated by lateral accretion and contain mud rip-up clasts, trough cross-laminations, silicified or carbonized logs, and localized pebble lags. Large dinosaur bones are also found rarely within channel lag deposits. Medium-to coarse-grained sandbodies are highly localized and restricted in area. Multi-story channel sandbodies record the highest energy flows within the Prince Creek, and probably represent meandering trunk channels within this multi-channeled alluvial system.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California