A core workshop: Late Mississippian (Chesterian) through early Pennsylvanian (Atokan) strata, Michigan Basin, USA
Published:January 01, 2013
Shannon Towne, Dave Barnes, David B. Westjohn, William B. Harrison III, 2013. "A core workshop: Late Mississippian (Chesterian) through early Pennsylvanian (Atokan) strata, Michigan Basin, USA", Insights into the Michigan Basin, Robb Gillespie
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Over 2000 linear feet of recently acquired conventional core and hundreds of well logs were analyzed to reevaluate regional, middle Carboniferous litho- and bio-stratigraphic relationships in the Michigan Basin, USA. The main objective of this workshop is to interpret the evolution of the Michigan Basin relative to other more extensively studied, North American cratonic interior basin successions in the Illinois and Appalachian basins. Stratigraphic relationships are evaluated in the Michigan, Bayport, and Saginaw formations on the basis of sedimentary lithofacies, contact relationships, and facies stacking patterns, in addition to new age determinations from several distinct pollen and spore assemblages. Core and well-log cross sections are presented to establish regional stratal geometry and corroborate stratigraphic relationships established in core studies. Biostratigraphic analysis has established the age range of these middle Carboniferous strata, which range from late Mississippian (Chesterian) through the early–middle Pennsylvanian (Morrowan and Atokan) North American stages, with no indication of significant hiatus relative to existing chronostratigraphic resolution. Significant soil horizons and incised valley-fill deposits found at the Mississippian-Pennsylvanian systemic boundary, however, are interpreted to represent the basal Absaroka sequence boundary.
Significant variations in eustatic, climatic, and tectonic signals recorded in Carboniferous strata of the Michigan Basin are found to be in close agreement with regional geological relationships established in recent sequence stratigraphic and basin analysis studies conducted in adjacent cratonic interior basins. Shallow, mostly restricted marine, mixed clastic, carbonate, and evaporite strata of the Mississippian Michigan and Bayport formations are overlain by carbonaceous debris-rich, terrigenous clastics dominated marginal marine and terrestrial strata of the Pennsylvanian Saginaw Formation. These strata record the complex interplay among second and higher order eustatic changes, global climate variations, and the culmination of Appalachian orogenic activity along the eastern margin of North America during the middle Carboniferous. These geological factors resulted in the dramatic transition from carbonate-dominated, stable cratonic interior basin sedimentation during the Siluro-Devonian to siliciclastic-dominated strata in the latest Devonian through Carboniferous in the Michigan Basin.
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Insights into the Michigan Basin
This guidebook volume is a compilation of field excursions offered at the 47th annual meeting of the North-Central Section of the Geological Society of America, held in Kalamazoo, Michigan, May 2013. These field trips examine a wide range of geological time intervals and topics, from Silurian salt, to Cretaceous cosmic impact, to newly interpreted Mississippian–Pennsylvanian Michigan stratigraphy, to Quaternary glacial landscape formation, sand dune development, and present-day coastal bluff stability/erosion issues. Trips geographically range throughout southern Michigan and northern Indiana from Detroit, Michigan, in the east to the Kentland Quarry in Indiana to the west.
Early depositional events within the Michigan Basin are examined deep underground in the Detroit Salt Mine (trip leaders: W.B. Harrison III and E.Z. Manos [onsite leader]). This salt mine has been in operation for more than 100 years, and extends for miles beneath the city of Detroit.
Kentland Quarry, located in northwest Indiana, is the site of a Cretaceous-aged meteorite impact (trip leader: J.C. Weber). This site allows for surface examination of a similar style impact event that occurred in now buried Ordovician-age (Trenton) rocks located in Cass County, (southwest) Michigan.
Mississippian-aged fluvial deposits have been traditionally classified as the youngest bedrock exposed in Michigan. These rocks crop out in the center of the Michigan Basin near Grand Ledge, Michigan (trip leaders: N.B.H. Venable, D.A. Barnes, D.B. Westjohn, and P.J. Voice). Younger, more recently identified, Pennsylvanian rocks will be the subject of a related core workshop at the Michigan Geological Repository for Research and Education (MGRRE) in Kalamazoo (workshop leaders: S. Towne, W.B. Harrison, and D.B. Westjohn).
The regional, surficial geology of southwest Michigan is highlighted by three field trips. The first trip details the glacial landforms and sedimentary features formed by the differing dynamics of the Michigan and Saginaw lobes of the Laurentide Ice Sheet (trip leaders: A.E. Kehew, A.L. Kozlowski, B.C. Bird, and J.M. Esch). The two other trips follow along the Lake Michigan eastern shoreline and examine development of sand dune complexes (trip leader: E. Hansen) and present-day, coastal bluff stability and erosion issues (trip leaders: R.B. Chase and J.P. Selegean).
- depositional environment
- Michigan Basin
- Middle Pennsylvanian
- North America
- planar bedding structures
- Saginaw Formation
- sedimentary structures
- stratigraphic units
- United States
- Upper Mississippian
- Bayport Formation