Cyclical Sedimentation of the Pennsylvanian Period and Its Significance

Weller, J. Marvin

doi:10.1086/623695

Cited by 210 publications

(96 citation statements)

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“…Beginning about 1960, workers started to interpret the genesis of various members of the Carboniferous cyclothem in light of the growing volume of research on modern depositional environments and facies. Numerous Carboniferous rock types similar to those defined in Western Illinois by Weller (1930) have been interpreted elsewhere to represent deposition in specific deltaic environments (Wanless, 1964(Wanless, , 1969Wanless and others, 1963Wanless and others, , 1969Wanless and others, , 1970D. Moore, 1959;Brown, 1969).…”

Section: Regional Depositional Settingmentioning

confidence: 99%

Clay Mineralogy in Relation to Deltaic Sedimentation Patterns of Desmoinesian Cyclothems in Iowa-Missouri

Brown

Bailey

Cline

et al. 1977

Clays and clay miner.

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AMtraet--Almost four decades of study of Desmoinesian strata of Middle Pennsylvanian age in southcentral Iowa and north-central Missouri have provided the stratigraphic control required to test the variation of clay mineralogy vertically and laterally within various paralic clay and shale facies. Local and regional variations in clay mineralogy within Desmoinesian strata are generally predictable and are in agreement with current knowledge of deltaic deposition. A principal environmental variation within a deltaic system is the change from normal marine salinities in deltaic marine environments to brackish-and fresh-water conditions in the marshy delta plains, in upper interdistributary bays, and within flanking interdeltaic embayments. Changes from marine to nonmarine facies coincide with a decrease in illite, and an increase in kaolin, mixed-layer clays, and in the percentage of expansible layers in the mixed-layer clay. The principal clay detritus entering the area was illite, which underwent various degrees of alteration in different aqueous and subaerial environments within deltaic and interdeltalc areas. Clay-mineral composition alone does not provide unique environmental answers. The distribution of clay-mineral suites within these systems, however, both supports the deltaie-interdeltaic depositional model and can be understood within the context of this framework.

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Section: Regional Depositional Settingmentioning

confidence: 99%

Clay Mineralogy in Relation to Deltaic Sedimentation Patterns of Desmoinesian Cyclothems in Iowa-Missouri

Brown

Bailey

Cline

et al. 1977

Clays and clay miner.

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“…Underclay is generally several centimeters to a meter thick, but may be as much as 6 m or more (Grim and Allen, 1938). It occurs in cyclothems that represent depositional sequences repeated throughout the Pennsylvanian (Weller, 1930(Weller, , 1931(Weller, , 1956Wanless, 1931Wanless, , 1947.…”

Section: Introductionmentioning

confidence: 99%

“…He also noted the sharp contact between the underclay and the coal, and the fact that Stigmaria never pass into the coal. Weller (1930Weller ( , 1931 also noted that both the underclay and the coal may occur alone and that the thickness of coal is not necessarily related to the thickness of its underclay. Thus, he concluded that the two are unrelated, and that underclay is a fossil soil that formed prior to peat accumulation.…”

Section: Introductionmentioning

confidence: 99%

Origin of an Underclay as Revealed by Vertical Variations in Mineralogy and Chemistry

Rimmer

Eberl²

1982

Clays and clay miner.

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Abstract--Regular vertical variations in mineralogy and chemistry indicate that underclay beneath the Herrin (No. 6) coal in southwestern Illinois has undergone in situ alteration. Alteration resulted from the downward movement of hydrogen ions, as indicated by the progressive leaching of acid-sensitive minerals adjacent to the coal. Mineralogical trends observed in the underclay with increasing depth below the coal include: (1) a decrease in the expandability of mixed-layer illite/smectite (I/S); (2) an increase in the amount of ordered US with respect to randomly interstratified US; (3) an increase in the amount of discrete illite with respect to expandable clays; and (4) an increase in chlorite and calcite. Ordered I/S is the dominant mixed-layer clay where calcite is present, but randomly interstratified US dominates where calcite is absent. The pH of the underclay also increases with depth. These trends are consistent with an origin by acid leaching of a preexisting mineral assemblage that included illite, chlorite, and calcite. Other acid-alteration trends may be expected for different precursor minerals and for different leaching intensities and durations.

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“…According to Udden [19] a cycle commences at the base of coal seam whereas Weller [20] gave a formation status to each cycle with sandstone at the base and coal seam at the top. Read and Dean [21] suggested the minimum thickness of a cycle to be 0.3 m while Casshyap [5] put it 1 m. In the present work, the sequence of strata of more than 1 m thickness with basal coarse member (conglomerate or sandstone) and terminating with a coal seam has been considered to constitute a cycle.…”

Section: Methodsmentioning

confidence: 99%

Cyclic Sedimentation of the Barakar Formation, Singrauli Coalfield, India: Statistical Assessment from Borehole Logs

Hota¹,

Adhikari²,

Mohanty³

et al. 2012

OJG

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The succession of lithofacies of a part of the Barakar Formation of the Singrauli coalfield has been studied by statistical techniques. The lithologies have been grouped under five facies states viz. coarse-, medium-, and fine-grained sandstones, shale and coal for statistical analyses. Markov chain analysis indicates the arrangement of Barakar lithofacies in the form of fining-upward cycles. A complete cycle consists of conglomerate or coarse-grained sandstone at the base sequentially succeeded by medium-and fine-grained sandstones, shales and coal seam at the top. The entropy analysis puts the Barakar cycles in A-4 type of cyclicity, which consists of different proportions of lower-, side-and uppertruncated cycles of lithologic states. Regression analysis indicates a sympathetic relationship between total thickness of strata (net subsidence) and number of coal cycles and an antipathic relationship between average thickness and number of coal cycles. The cyclic sedimentation of the Barakar Formation was controlled by autocyclic process, which occurred due to the lateral migration of streams triggered by intrabasinal differential subsidence. In many instances, the clastic sediments issued from the laterally migrating rivers interrupted the sedimentation resulting in thinner cycles in areas where the numbers of cycles are more. Principal component and multivariate regression analyses suggest that the net subsidence of the basin is mostly controlled by number and thickness of sandstone beds and coal seams.

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Cyclical Sedimentation of the Pennsylvanian Period and Its Significance

Cited by 210 publications

References 0 publications

Clay Mineralogy in Relation to Deltaic Sedimentation Patterns of Desmoinesian Cyclothems in Iowa-Missouri

Clay Mineralogy in Relation to Deltaic Sedimentation Patterns of Desmoinesian Cyclothems in Iowa-Missouri

Origin of an Underclay as Revealed by Vertical Variations in Mineralogy and Chemistry

Cyclic Sedimentation of the Barakar Formation, Singrauli Coalfield, India: Statistical Assessment from Borehole Logs

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