Contributions Series Nr. 27

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Miospores of the Kekiktuk Formation (Lower Carboniferous), Endicott Field Area, Alaska North Slope
Robert L. Ravn
1991

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178 pp.

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Description

Abstract

The Kekiktuk Formation of the Alaska North Slope is a non-marine unit of Early Carboniferous age that crops out in the Brooks Range and is present in the subsurface over a large area. In the vicinity of Endicott Field near Prudhoe Bay, where it forms a major hydrocarbon reservoir, it is divided into three informal units: A lower member consists mainly of shales and coals, with minor sandstones; a middle member is dominated by thick sandstones and conglomerates recording deposition mainly by braided stream systems, with minor intervals of shale and coal; an upper unit, consists of a complex of coals, shales and sandstones representing a variety of lower-energy fluvial deposits, developed in the early stages of a long transgressional episode that resulted in the deposition of strata of marine origin above the Kekiktuk Formation.

In the Endicott Field area, the Kekiktuk Formation yields a prolific and diverse miospore flora containing forms characteristic of the boreal Monilospora Suite, or Region, widely described and discussed as evidence of marked provincialism among Early Carboniferous miofloras. It ranges in age from ?latest Tournaisian/early Visean to early late Visean, equivalent to the Pu-VF miospore biozones of northwestern Europe. The localities presently nearest to northern Alaska from which miospores of similar age have been described are in the Northwest Territories of Canada. The Kekiktuk mioflora closely resembles those from northwestern Canada, but it also bears a strong resemblance to miospore assemblages reported from Spitsbergen. This latter similarity supports a paleogeographic reconstruction placing the northern Alaska shelf near Spitsbergen during Visean time.

Two new miospore genera are described, Granomurospora Ravn n. gen., and Teratodaspora Williams & Ravn n. gen., along with the following new species: Anapiculatisporites kekiktukensis, Apiculiretusispora microseta, Cingulizonates flammulus, Colatisporites? papillatus, Converrucosisporites owensii, Convolutispora? occulta, “Corrugatisporites borealis, Densosporites steinii, Densosporites undulatus, Foveosporites gracilifoveatus, Foveosporites? wigginsii, Grandispora melvinii, Granomurospora bensonii, Heterotriletes ternensis, Knoxisporites plaryradiatus, Loplwzonotriletes undulimarginatus, Murospora complicata, Murospora tumida, Neoraistrickia coronata, Neoraistrickia williamsii, Pilosisporites xiphoformis, Reticulatisporites labiatus, Reticulatisporites waloweekii, Spelaeotriletes asperatus and Verrucosisporites endicottensis. A number of other taxa are reassigned or emended.