Mississippi River Arch
Location
Along the Mississippi River in southeastern Iowa, northwestern Illinois, and northeastern Missouri (fig. 1)
References
Howell 1935, Wilson 1939, Lee 1943, Bell et al. 1964, Edmund and Anderson 1967, Atherton 1971, Bunker et al. 1985
Description
The name Mississippi River Arch has been applied rather vaguely and loosely to the structural divide between the Illinois and Forest City Basin Basins. Bunker et al. (1985) advocated that the term Mississippi River Arch be restricted to the present arch that developed after the Morrowan (early Pennsylvanian) Epoch. A basin existed astride the position of the arch in the Quad Cities area during the Morrowan Epoch, and sediments (Caseyville Formation) were deposited. An earlier arch existed in the same general area and was beveled by the sub-Kaskaskia (pre-middle Devonian) unconformity. Bunker (1981) proposed the name Northeast Missouri Arch for the pre-Kaskaskia structure, the axis of which lay somewhat west of the post-Morrowan Mississippi River Arch. The recommendations of Bunker are accepted here.
