Foliated breccias in the active Portuguese Bend landslide complex, California: bearing on melange genesis.

Measured displacement rates range from less than 1 to greater than 30 mm/day on different parts of the landslide,with total displacements over the last 30 yr ranging from about 120 to greater than 150 m. Six types of breccia, each locally with a foliated matrix, were recognized in the active landslide complex and are absent outside the landslide complex. The size breccia types represent the principal types of melange that occur in ancient accretionary settings. Furthermore, the previous classification of melanges into 'olistostromal' and 'tectonic' types is artificial, because the landslide is clearly an olistostrome type that is currently producing structures indistinguishable from those produced tectonically. -from Authors