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Contents |
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Geological Setting |
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The flat-lying, poorly consolidated sediments which include the mummified forests are assigned to the Buchanan Lake Formation (Ricketts 1986). The study site is east of the Geodetic Hills on Axel Heiberg Island (79°55'N, 89°02'W). The Buchanan Lake Formation, (Ricketts 1986, 1991, 1994), consists of four members composed of interbedded non-marine conglomerate, sandstone, siltstone, and lignitic beds. The Upper Coal member contains the forests we propose to study. At the fossil forest site, the Upper Coal member is represented by approximately 400 m of sandstone, siltstone and forest layers. Individual sandstone-forest sequences are 1.5-5.0 m thick, composed of basal sandstone beds that fine upward into silty-sands and finally into siltstones. The sequence is commonly capped by the organic remains of a forest. Figure 1 shows the section of this sequence which has the most potential for the studies we propose. During the Eocene, foreland style folding and faulting associated with uplift of the Princess Margaret Arch to the west, resulted in formation of the Axel Heiberg Basin and deposition of the Buchanan Lake Formation (Ricketts 1987, 1991; Ricketts and McIntyre 1986). Erosion of Upper Paleozoic and Mesozoic bedrock along the Stoltz Thrust resulted in the syn- and post-orogenic deposition of gravels, sands, and silts by braided and meandering river systems and debris flows in the Axel Heiberg Basin (McIntyre 1991; Ricketts 1986, 1987, 1991; Ricketts and McIntyre 1986; Tozer 1960). Figure 2 shows the spatial relationships among the Stoltz Thrust, the Buchanan Lake Formation, and the associated paleoenvironments. The fossil forests under study constituted the meanderplain flora.
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