The basis of modern fresh-water peatland (mire) classification, namely ground-water influence and source of ionic input, has been adopted in this study for ancient mire analysis. Trends that result from a modern mire’s evolution from a rheotrophic (ground-water influenced) planar to ombrotrophic (solely rain-fed), raised status, under decreasing influence of ground water, include decreasing pH levels, nutrient/ionic supply, ash content, species diversity, and ratio of arboreous to herbaceous vegetation. These attributes are inferred to give rise to the following upward trends within a coal seam: enhanced preservation and reduced biochemical geliflcation within similar tissues; decreasing abundance of liptinite macerals of aquatic affinity, sulfur (especially pyritic) content, and waterborne ash; and decreasing floral diversity. Reversals in these trends may signal change in the trophic status of the ancestral mire (e.g., deflation). The identification of such trends relies heavily upon the description of vitrinite in terms of relative geliflcation. The significance of Eh and the historical use of inertinite in paleomire analysis is questioned. The ancestral mire of the Westphalian B No. 3 seam of the Springhill coalfield, Cumberland Basin, Nova Scotia, formed between a piedmont of coalesced, retreating alluvial fans and the medial reaches of a basin-axis channel belt. The lithologically distinct piedmont, inner mire, and riverine zones of the seam reflect this geomorphic setting. Modeling of a maceral-based index of ground-water influence (strongly gelified tissues and mineral matter versus well preserved tissues) led to the deduction that the paleomire originated as a rheotrophic, and presumably planar, ecosystem that evolved progressively toward a less ground-water-influenced (mesotrophic) state, and possibly to an ombrotrophic, weakly domed system within the inner mire. This maceral-based method suggests a succession of mire types from swamp to fen (and questionably to bog) representing the classic hydroseral succession that forms by the autogenic process of terrestrialization. Contrary to the maceral-based evidence of progressive, albeit weak, raising of the mire surface, ash, sulfur, and miospore diversity increase, and lithotypes become duller upward within the upper third of the seam in the inner zone, suggesting that the mire may have ultimately reverted to a more ground-water-influenced state. A decrease in pH, inferred from an upward increase in tissue structure and decrease in geliflcation, accompanied inner mire development; elsewhere conditions were less acidic. The paleomire flora was dominated throughout by the arboreous lycopsids Lepidodendron hickii and Anabathra (cf. Paralycopodites ), confirming the rheotrophic nature of the ecosystem and the prevalence of flooded conditions. Floral succession of these arboreous lycopsids is evident within the inner mire. Groundwater discharge from alluvial fans at the piedmont margin favored conditions for the colonization of the forest flora. The feedback mechanism of lateral or upslope paludification was aided by the rapid, noncompetitive growth strategy of the arboreous lycopsids. At the riverine margin, autogenic evolution of the ecosystem was stymied by allogenic fluvial processes and by differential compaction about entombed multistory sandstone bodies. Lithotype trends record a general, but similar history of mire development. The ultimate demise of the mire is ascribed to allogenic change, potentially involving precession-induced climate change in concert with basin subsidence and sediment supply.

Recent sedimentation patterns in the central Sumatra basin, Republic of Indonesia, may help to explain the cyclic stratigraphy of the Pennsylvanian System of the eastern United States. Modern influx of fluvial siliciclastic sediment to the epeiric seas of the Sunda shelf, including the Strait of Malacca, appears to be highly restricted by rain forest cover within the ever-wet climate belt of equatorial Sumatra. As a result, much of the marine and estuarine environments appear to be erosional or nondepositional except for localized deposition of sediment in slack water areas, such as the down-stream end of islands. Contemporaneously, thick (>13 m), laterally extensive (>70,000 km 2 ), peat deposits are forming on poorly drained coastal lowlands. Modern peat formation in this study, therefore, is not coeval with aggrading fluvial siliciclastic systems, a situation that commonly is assumed in many depositional models of coal formation. The stratigraphy of Pleistocene and Holocene sediments on the Sunda shelf, as well as those of the Pennsylvanian System, appears to be better explained by the allocyclic controls of climate and sea-level change on sediment flux rather than by depositional models that are based on autocyclic processes. The objective of this paper is to evaluate allocyclic and autocyclic controls on sedimentation in an epeiric setting in a humid (ever-wet) tropical region. Of particular interest are the factors that control peat formation and siliciclastic sediment flux in rivers, estuaries, and open marine environments.