From Cyclothems to Sequences: The Record of Eustasy and Climate on an Icehouse Epeiric Platform (Pennsylvanian-Permian, North American Midcontinent)

Abstract

The stratigraphic succession of the North American Midcontinent contains a high-resolution (Ͻ 100,000 year) record of sea level and climate change spanning the Pennsylvanian-Permian boundary. Outcrop-based sequence stratigraphic analysis on the upper Wabaunsee, Admire, and lower Council Grove groups in Kansas and Nebraska reveals a hierarchy of fifty-one fifth-order meter-scale cycles grouped into five fourth-order composite sequences. Fifth-order cycles are bounded by subaerial unconformities in nearshore settings and correlative conformities in offshore settings, and are therefore very thin depositional sequences. Lowstand systems tracts, observed only in nearshore deposits, are expressed as sandy, incised-valley fills in these meter-scale cycles. Transgressive systems tracts, which are dominated by carbonate deposition, include coastal evaporites indicating arid climatic conditions. Highstand systems tracts, which are dominated by siliciclastic deposition, include thin but persistent coals in muddy coastal successions indicating humid climatic conditions. Paleosols at sequence boundaries evolve from vertic to calcic, indicating climate change from relatively humid to relatively arid conditions during subaerial exposure. This indicates that relatively arid climate coincided with eustatic lows while relatively humid climate coincided with eustatic highs on this low-latitude platform. Composite sequences are bounded by subaerial, angular unconformities and display a transgressive-regressive stacking pattern of meter-scale cycles. The highresolution stratigraphic record of the Midcontinent helps constrain the rate and magnitude of environmental change in ancient icehouse conditions and can serve as a baseline of environmental change for comparison with other coeval successions.

Sequence stratigraphy and onlap history of the Donets Basin, Ukraine: Insight into Carboniferous icehouse dynamics

“…Donets cyclothems range from 5 to 100 meters in thickness (most between 40-60 m) and are comparable to other Carboniferous cyclothems (e.g. Heckel, 1977, Tandon andGibling, 1994;Olszewski and Patzkowsky, 2003). Not only are stratigraphic patterns observed in single cores or outcrop, but the laterally extensive marker beds permit the NOTICE: This is the author's version of a work accepted for publication by Elsevier.…”

Facies arrangement and cyclostratigraphic architecture of a shallow-marine, warm-water carbonate platform: the Late Carboniferous Ny Friesland Platform in eastern Spitsbergen (Pyefjellet Beds, Wordiekammen Formation, Gipsdalen Group)

“…On the northern hemisphere, comparable successions have been studied within the North American Midcontinent by Boardman and Heckel (1989), West et al (1997) and Olszewski and Patzkowsky (2003), and in the Sverdrup Basin of the Canadian Arctic by Beauchamp (1994), Morin et al (1994) and Beauchamp and Desrochers (1997). Håkansson and Stemmerik (1989), Cecchi et al (1995), , Stemmerik and Worsley (1995), Stemmerik (1997) and Samuelsberg and Pickard (1999) presented similar features in the strata of the Wandel Sea Basin from northern Greenland and the Barents Sea.…”

Wetland-Dryland Vegetational Dynamics in the Pennsylvanian Ice Age Tropics

“…During any such individual cycle, climate also changes systematically (Cecil et al 1985(Cecil et al , 2003bTandon and Gibling 1994;Olszewski and Patzkowsky 2003;Falcon-Lang 2004;Feldman et al 2005;DiMichele et al 2009a;Horton et al 2012), strongly covarying with sea level changes. Within the pages of the articles cited above and others, however, the reader will find disagreement regarding the sea level position of key climate indicators, particularly paleosols (seasonally dry) and especially coals (wet with minimal seasonality): the principal points of contention regarding coals are that they formed during lowstand, during sea level rise and transgression, or at highstand, thus covering nearly all of the possibilities.…”