Coal seams and their surrounding strata share several spatial and genetic relationships, some of which are common to all sediments, while others are specific to the transition from primarily inorganic to organic sedimentation and vice versa. Although coal seams and their enclosing inorganic sediments differ in many aspects, a mutual influence on each other’s composition and structural relationships is often observed in the vicinity of their contacts. Examples are the distribution of elements and minerals, which may be quite uniform in a vertical seam section, but undergo considerable changes in concentration near the sediment/coal interface (Nicholls 1968; Gluskoter et al. 1977; Pareek and Bardhan 1985). The observation of Dorsey and Kopp (1985) of a gradual upward decrease in elemental concentration in the Pewee Seam of the Wartburg Basin in Tennessee, U.S.A., followed by a sharp reversal of the trend (increase in Si, Al, Ti, K, Mg) below the seam roof is probably not an isolated occurrence. The authors regard the gradual upward element depletion as an indication of the decreasing influx into the Pewee swamp of terrigenous minerals, which was followed by renewed flooding and abundant sediment supply, thus terminating peat accumulation. While this interpretation is probably correct, an additional factor in the upward elemental depletion may be the recycling of essential elements, when plants cannot obtain sufficient nutrients from a deeply buried and water-logged soil, or because of the cessation of nutrient supply by flood waters.
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- The Relationship Between Coal and Interseam Sediments
Claus F. K. Diessel
- Springer Berlin Heidelberg
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