Paleotopography and Sea-Level Controls on Facies and Thickness Variability of Transgressive Limestones: Upper Pennsylvanian Merriam Limestone, NE Kansas

Paleotopography and Sea-Level Controls on Facies and Thickness Variability of Transgressive Limestones: Upper Pennsylvanian Merriam Limestone, NE Kansas
Kansas Geological Survey
Open-file Report 2003-26

After erosion into Bonner Springs Shale and initial transgression, the first Merriam deposits occur in channels, and drape channel margins. The facies consist of silty-sandy skeletal PS, containing Bonner Springs clasts and aligned skeletal fragments, deposited during continued transgression.
With continued rise in sea-level, siliciclastic influx decreases, and cleaner skeletal WS-PS containing whole, unabraded fossils is deposited in channels, also draping the margins.
Shallow-subtidal, low-energy brachiopod, Osagia WS forms in channels and on surrounding highs, blanketing paleo- topography.
High-energy, shallow-subtidal coated-grain GS (oncoids and ooids) form on highs, with lower energy skeletal WS-PS deposited in quieter channel areas. Beds in channels locally contain coated-grains likely washed in from surrounding highs. Most accommodation in channels is filled.
Siliciclastic influx into the area (either due to delta lobe switch or sea-level fall?) further subdues any remaining topography.
Deeper subtidal Phylloid-algal WS are deposited over the entire area, displaying consistent thickness and facies character, indicating relief had been largely filled.

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Last updated May 2003
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