Description
The Bedford Canyon Formation in the northern Santa Ana Mountains includes three subdivisions: (1) lower limestone-bearing pebbly and conglomeratic shale, ±300 m thick, (2) sandstone-shale series, ± 2,500 m thick, and (3) upper limestone-bearing pebbly and conglomeratic shale, ± 300 m thick. Fossils indicate Bajocian and Callovian ages for units 1 and 3, respectively. Intrusive feeders related to the Santiago Peak Volcanics intrude the Bedford Canyon Formation. Most of the exposed Bedford Canyon Formation is overturned. Folds, fault trends, general inclinations, and stratigraphy indicate that the northern Santa Ana Mountains are part of an easterly dipping recumbent anticline, the upper limb of which has been removed by erosion. The remaining overturned limb now forms the core and eastern flank of the range. Much of the crest is occupied by intrusive rocks. The upper and lower pebbly shales were deposited in a shallow environment whereas the sandstone-shale series represents an upper-bathial flysch-like deposit transported by turbidity currents. Sole marks, graded bedding, and horizontal-, cross-, and wavy-bedding and lamination are the most abundant sedimentary structures. Paleocurrent directions indicate a source area located to the east.
