- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
Joints (fractures) are propagated from areas of high to areas of low stress. They may originate at inhomogeneities on, or by slickensiding along bedding planes. Plumose marks on the surface of joints radiating from volcanic, meteor, or man-made explosion craters should, in stratified rock, reveal whether the joints were propagated with their leading edge convex or concave forward.