Palynological correlation of major Pennsylvanian (Middle and Upper Carboniferous) chronostratigraphic boundaries in the Illinois and other coal basins

Abstract

Palynology provides chronostratigraphic correlations of Pennsylvanian (Middle and Upper Carboniferous) strata between the Illinois basin, which is the main focus of this study, and other coal basins in the UnitedStates, western Europe, and the Donets basin. Published reports and recent palynological analyses of coal samples from the Illinois basin, western part of the Midcontinent, and the Appalachian coal region were used in making the correlations. Correlations are made on the basis of first and last appearances and major changes in relative abundance of spore taxa. Studies of plant megafossils and faunas are discussed briefly in relation to some of the palynological correlations. Stratigraphers in the Midcontinent have considered the Lower Pennsylvanian Series equivalent to the Morrowan Stage, the Middle Pennsylvanian equivalent to the Atokan and Desmoinesian Stages, and the Upper Pennsylvanian equivalent to the Missourian and Virgilian Stages. I propose extending this nomenclature to the Illinois Basin. The chronostratigraphic classification of the Pennsylvanian System in the western part of the Midcontinent region was adopted by the Illinois State Geological Survey for the Illinois basin largely on the basis of studies of marine fossils. The precise position of the Morrowan−Atokan Stage boundary in Illinois is still not satisfactorily known. It generally has been correlated with the base of the Tradewater Formation but is herein correlated with the top of the Reynoldsburg Coal Bed, which is at the base of the formation. The top of the Morrowan occurs just above the base of the Tradewater Formation in western Kentucky and in the upper part of the Mansfield Formation in Indiana. I propose that the Atokan−Desmoinesian Stage boundary in Illinois correlates with the top of the Seville Limestone Member and equivalent limestone beds in Indiana and western Kentucky. The Desmoinesian−Missourian (Middle−Upper Pennsylvanian) boundary is correlated with the base of the Lake Creek Coal Member or, if that is not present, at the top of the Lonsdale Limestone Member in western Illinois and the top of the middle bench of the West Franklin Limestone Member in eastern Illinois and western Indiana. The Missourian−Virgilian Stage boundary has been correlated, in the absence of adequate palynological data, with strata a little below the Shumway Limestone Member as determined by fusulinid evidence. The Lower−Middle Pennsylvanian boundary in the Pennsylvanian stratotype in West Virginia proposed by the U.S. Geological Survey (USGS) is older than the Lower−Middle Pennsylvanian boundary of the Midcontinent. The latter correlates with the base of the Pounds Sandstone Member in Illinois and the Bee Spring Sandstone Member in western Kentucky. Although the Middle−Upper Pennsylvanian Series boundary has been correlated with the boundary between the Allegheny and Peppers, R. A., 1996, Palynological Correlation of Major Pennsylvanian (Middle and Upper Carboniferous) Chronostratigraphic Boundaries in the Illinois and Other Coal Basins: Boul...

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

“…Descriptions of the macroflora, both compression-impression and anatomically preserved, can be found in numerous publications dating to the early 1800s, when formal paleobotanical taxonomic nomenclature was established (von Sternberg 1820). The palynoflora is equally well known, primarily from studies of coal and associated rocks (Peppers 1996). There were two major species pools that comprised this flora, and these succeeded each other in time.…”

“…However, comparisons at a broader level show consistent differences in quantitative aspects of composition, such as the more common occurrence of the lycopsid Sigillaria or the greater dominance of pteridosperms (King et al 2011;Wagner and Castro 2011) in mineral substrate wetlands than in peat swamps. Some larger-scale patterns, such as the qualitative rise in importance of the marattialean fern clade in wetlands of the late Middle Pennsylvanian (Phillips et al 1974;Pfefferkorn and Thomson 1982;Phillips and Peppers 1984;Peppers 1996;Dimitrova et al 2005;Dimitrova and Cleal 2007) or the decline in wetland cordaitales (Phillips and Peppers 1984;Raymond et al 2010), are detectable in both forms of preservation and appear to occur at approximately the same time in both, despite differences in quantitative aspects (for the rise in tree ferns, cf. Pfef-ferkorn and Thomson 1984or Peppers 1996; the timing is the same even though quantitative expression differs).…”

“…This seasonality becomes apparent even during the wet phases of glacial-interglacial cycles beginning near the Desmoinesian/Atokan (Bolsovian-Asturian) boundary, revealed by changes from ombrotrophic domed peats to rheotrophic planar peats (Cecil 1990), associated with increases in coal sulfur (Cecil et al 1985;Neuzil et al 2005) and with changes in sandstones, indicating a transition from wet low-seasonality climates to greater seasonality (Bertier et al 2008). The wetland flora also undergoes many compositional and dominance-diversity changes at this same time (Pfefferkorn and Thomson 1982;Phillips and Peppers 1984;Peppers 1996), much more abruptly than the seasonally dry flora.…”

“…Analysis of the wetland biome, particularly that of peat-forming landscapes, indicates a considerable amount of conservatism in species composition and dominance-diversity structure through millions of years and multiple glacial-interglacial cycles. This assessment has been based on both macrofossils and microfossils recovered from successive coal beds Willard and Phillips 1993;DiMichele and Phillips 1996b;Peppers 1996;Pfefferkorn et al 2000Pfefferkorn et al , 2008DiMichele et al 2002;Willard et al 2007), representing the wettest parts of glacial-interglacial cycles. It appears, furthermore, to be undergirded by considerable phylogenetic conservatism in the resource centroids of the major clades, resulting in phylogenetically conservative patterns of species replacement through time (DiMichele and Phillips 1996a), so-called niche conservatism (this is currently an active field of study; see Ackerly 2003;Wiens 2004;Wiens and Graham 2005;Wiens et al 2010).…”

Lycopsida from the lower Westphalian (Middle Pennsylvanian) of the Maritime Provinces, Canada

“…The remains of large, arborescent lycopsids in coalbearing deposits of Pennsylvanian age have generally fascinated paleobotanists and coal geologists. The predominant role of lycopsids in coal formation is generally acknowledged (e.g., DiMichele and Phillips 1985), and is particularly obvious from palynological data (e.g., Peppers 1996). Large external impressions of lycopsid trees caught the eye of the early paleobotanists, particularly those connected with coal mining (e.g., Graf Kaspar von Sternberg, whose last resting place, near Radnice in Bohemia, is adorned by a superb specimen of Lepidodendron aculeatum).…”