Westfield Dome
Part of the La Salle Anticlinorium
Location
Northwestern Clark and parts of Coles and
Cumberland Counties (G-7,8)
References
Mylius 1923, 1927, Moulton and Young 1928, Cohee 1941, Clegg 1959, 1965a, b, Bristol and Buschbach 1973, Stevenson et al. 1981
Description
The Westfield Dome, formerly called the Parker Dome, is an asymmetrical box-fold with a long steep western limb (the Charleston Monocline), a gently dipping eastern limb, and a slightly domed crest. The dome underwent uplift before Pennsylvanian sedimentation, and additional uplift after Pennsylvanian time. Structural relief, therefore, is greater on pre-Pennsylvanian than on Pennsylvanian strata (see table).
The Westfield Oil Field, developed on the dome, has been producing since 1904 from Pennsylvanian, Valmeyeran, and Galena reservoirs.
| Structural horizon | Relief of western limb | Relief of eastern limb |
|---|---|---|
| PENNSYLVANIAN | ||
| Herrin (No. 6) Coal Member (Clegg 1965b) |
1 ,060 ft (323 m) | 600 ft (183 m) |
| Colchester (No. 2) Coal Member (Clegg 1965b) |
1,170 ft (357 m) | 680 ft (207 m) |
| DEVONIAN | ||
| Base of New Albany Group (Stevenson et al. 1981) |
2,700 ft (823 m) | 1 ,200 ft (366 m) |
| ORDOVICIAN | ||
| Top of Galena Group (Bristol and Buschbach 1973) |
2,500 ft (762 m) | 1,100 ft (336 m) |
