Taxonomy of Cretaceous–Paleogene coniferous woods and their distribution in fossil Lagerstätten of the high latitudes
M. Dolezych, L. Reinhardt, J. Kus, V. Annacker, "Taxonomy of Cretaceous–Paleogene coniferous woods and their distribution in fossil Lagerstätten of the high latitudes", Circum-Arctic Structural Events: Tectonic Evolution of the Arctic Margins and Trans-Arctic Links with Adjacent Orogens, Karsten Piepjohn, Justin V. Strauss, Lutz Reinhardt, William C. McClelland
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Anatomical analyses of fossil woods, supplemented by information from coal petrographic investigations, provide data for reconstructing the Cretaceous–Paleogene, mostly swampy woodland vegetation of the high latitudes. This paper is focused on the taxonomic description of conifers that have been recovered from a number of plant fossil Lagerstätten in Nathorstland, Yukon North Slope–western Mackenzie Delta, Ellesmere Island, northern Trolleland, and Kotel’nyi Island. The investigation revealed a relatively low taxonomic diversity. Wood-anatomical identification of Taxodioxylon vanderburghii provides evidence for the genus Metasequoia. The determination of Glyptostroboxylon cf. rudolphii demonstrates the most likely presence of Glyptostrobus, and the genus Cunninghamia is proved by the identification of Glyptostroboxylon tenerum. Moreover, this first evidence of Cunninghamia in the high latitudes establishes this plant as an “Arctic conifer.” Piceoxylon laricinoides (Høeg) comb. nov., a new combination, is proposed for a fossil wood species that represents the genus Larix. Fossils identified as Protopiceoxylon woods, Protopiceoxylon sp., and Protopiceoxylon yukonense represent the extinct gymnospermous Protopinaceae group. A fossil forest from the Split Lake Lagerstätte focusing on the habitus of in situ trunks and stumps was reconstructed. The vegetation encompasses a succession with three stages, an Equisetum reed facies, a Metasequoia swamp forest facies, and a Larix swamp forest facies. The taxonomic investigation suggests a widely distributed zone of vegetation with various conifers in the high latitudes. The lignite samples are characterized by predominantly woody (xylite) tissues with well-preserved, mummified stems and roots and a variable content of liptinite macerals, mostly resinite and suberinite. The intensive yellow fluorescent textinite of characteristic zoned structures and distinct microspores was observed in all investigated lignites.