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Which deposits are typical of Pennsylvanian cyclothems in the Northern Hemisphere?

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Carboniferous paleogeography — Carboniferous Period Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the late Carboniferous Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

In the Northern Hemisphere, Pennsylvanian cyclothems are characterized by repetitive, alternating sequences of marine and nonmarine sedimentary deposits that reflect the advance and retreat of shallow seas over deltaic plains.123

While these sequences vary, a typical coal-bearing cyclothem in the eastern interior of North America consists of a nonmarine lower portion and a marine upper portion. The nonmarine sequence generally includes, in ascending order:3
* Sandstone
* Shale
* "Freshwater" limestone
* Underclay (seat-earth)
* Coal bed13

The marine portion of the sequence typically exhibits alternating beds of shale and limestone, often containing marine fossils. In contrast, cyclothems in the western midcontinent are predominantly marine, involving alternations of limestone and shale that reflect transgressive and regressive events. These cycles often begin with sandy shale, progress through carbonate mudstones to a black shale (marking maximum transgression), and return to sandy shale. These deposits are notable for their lateral persistency, allowing individual beds to be traced over hundreds of kilometres.13