No abstract

No abstract

No abstract

Chart 1 summation), caused reorientation of the Missouri River system southeastward to the Mississippi River, resulting in many stream captures and other geomorphic changes (Fig. 4B). Each time the ice blocked eastward-flowing rivers, proglacial lakes formed, spilled across divides, and developed new courses around the glacial margin. The present course of the Missouri River through North and South Dakota is chiefly along a late Illinoian ice margin. The Platte River evolved through spasmodic uplift of the Chadron arch (Stanley and Wayne, 1972) and sev

Permian coal beds occur within a fluvial sedimentary sequence in the Victoria Group of the Beacon Supergroup from the Ohio Range to northern Victoria Land, a 2000-km-long belt in the TransantarcticMountains, Antarctica. Although coal beds as thick as 10.7 m have been reported, most beds are thinner than 2 m. Coal beds are generally lenticular, and exposure along strike is commonly not more than 1-3 km. In northern Victoria Land the Takrouna Formation contains coal in the small North Victoria Basin; in southern Victoria Land the larger South Victoria Basin contains the Weller Coal Measures; and the southernmost and largest basin, Nimrod-Ohio Basin, from the Nimrod Glacier to the Ohio Range, contains the Buckley Formation and its equivalents. One hundred forty-four published analyses of Permian coal from this region show that ash contents range from 3.2 to almost 50% with an arithmetic mean of 15.3%, and sulfur ranges from 0.0 to 4.8% with an arithmetic mean of 0.57%. Apparent rank of the coals ranges from high-volatile C bituminous coal to anthracite, but most of the coal samples have apparent ranks of low-volatile bituminous coal and semianthracite. The relatively high rank of much of the coal of the Transantarctic Mountains probably is related both to heat and pressure from sediment load and to heat from igneous intrusion; the dominant mechanism, however, remains to be determined. Paucity of data on coal thickness and distribution dictates that coal resource estimates be assigned to the hypothetical classification. Calculations based on published geologic maps, geologic descriptions, and measured sections indicate hypothetical resources of 3 billion metric tons in the North Victoria Basin, 50 billion metric tons in the South Victoria Basin, and 100 billion metric tons in the Nimrod-Ohio Basin. "Coal Potential of Antarctica." Those authors show the localities of all major and most minor coal occurrences in Antarctica including Permian, Triassic, Jurassic (?), Cretaceous, and Tertiary coals. They summarize in tabular form the most important articles about each major area and present and discuss representative coal analyses from each area where analyses are available. Particularly useful is their bibliography of nearly a hundred references covering coal in all parts of the continent. Rose and McElroy [1987] and Whitby et al. [1983] discuss some of the difficulties and limiting factors that face any attempt to exploit coal in Antarctica. Included are a unique ecosystem, long distances to markets, and the logistic and human problems involved in maintaining a small remote settlement, as well as the technological problems of working in a cold dry climate. Problems analogous in some ways have been faced in Spitzbergen,