Birkbeck Syncline

Part of the Upper Mississippi Valley Zinc-Lead District

Location

T29N, R1E, Jo Daviess County (A-3)

References

Willman and Reynolds 1947, Bradbury et al. 1956

Description

The Birkbeck is a gentle fold that was mapped from outcrops and prospect borings for lead and zinc. The axis strikes north-northwest and is slightly sinuous. Dips on both flanks are gentle from 1° to 4°; maximum structural relief is about 50 feet (15 m). Two zinc and lead mines formerly operated within the syncline.