Circulation patterns in the Late Pennsylvanian North American Midcontinent Sea inferred from spatial gradients in sediment chemistry and mineralogy

The North American Midcontinent Sea (NAMS) reached its maximum extent during glacio-eustatic highstands of the Late Paleozoic Ice Age, during which organic-rich “core shales” accumulated under a stratified water column with anoxic deep waters. The core shales of cyclothems are composed of a lower organic-rich laminated black shale and an upper bioturbated gray shale. The present study investigates circulation patterns within the NAMS by...