Tolu Arch

Part of the Fluorspar Area Fault Complex

Location

Hardin County, Illinois, Crittenden and Livingston Counties, Kentucky (plate 1)

References

Baxter et al. 1963, Trace and Amos 1984

Description

The origin of this name is unknown; the feature has been labeled both as an arch and a dome. The term arch is preferable for such an elongated feature. The arch trends about N40°W, toward Hicks Dome, which can be regarded as its culmination. Tolu Arch is greatly broken by northeast-trending block faults. Ultramafic intrusions that radiate from Hicks Dome are numerous along the Tolu Arch. The origin of the arch is uncertain. It may be a partially collapsed magmatic or explosive volcanic uplift.

Figure(s)

Plate 1   Structural Features in Illinois