Abstract

Raymond Canyon is an unique geologic showplace that displays a well exposed structural cross section through part of the Crawford thrust sheet, Idaho-Wyoming thrust belt. It contains excellent exposures of steeply dipping upper Paleozoic and Mesozoic strata, a splay in the hanging wall of the Crawford thrust, small-scale folds and northwest-trending strike-slip faults. Formations exposed range in age from Late Pennsylvanian to Tertiary (Pliocene) and are generally thinner than in nearby areas to the west and northwest.

Raymond Canyon lies on the upper plate of the Crawford thrust in the central unit of an imbricate stack of shallowly dipping faults. A steeply dipping splay off the Crawford places older Jurassic and Triassic rocks on younger Jurassic rocks near the middle of the canyon.

Numerous northwest-trending strike-slip faults, with both left- and right-lateral separation, occur. Some die out to open concentric folds within the Rich Member of the Twin Creek Limestone while others are tear faults displacing the thrust splay.