FAULT INDUCED FOLDS

Fault-related folding was one of the first classes of folding recognized by geologists (Powell: monoclines, forced folds; Willis: thrust folds; Rich: Ramp folds), mostly in the late 1800's. Progress on understanding of the particular mechanisms of fault-related folding has been very slow, though. The first mechanism to be carefully worked out was,  by John L. Rich in 1934. At that time he was a professor at the University of Cincinnati and was known for his work in geomorphology, sedimentology and oil geology. He was contemplating, apparently, peculiar cross sections of some southern Appalachian folds mapped by a geologist by the name of Butts. Briefly, Rich deduced that the folds could have formed by duplication of strata caused by thrusting over a ramp. He demonstrated the mechanism experimentally.

At Purdue,  the mechanics of Rich's ramp folding mechanisms were worked out in the late 1970's at Cincinnati. Working on monoclines began in the mid 1970's at Stanford. Ze'ev Reches described a wonderfully exposed monocline in the Grand Canyon and we developed some preliminary analyses of the mechanics of monocline formation at that time. Visit page kaj.html