Geology of Canyon Country

General Facts

Canyon Country sits atop rock that has been uplifted, folded, and eroded over the last few million years. Most of the hills are made up of rock from the 23 – 30 million year old Miocene Mint Canyon Formation. It was probably uplifted during the latter part of the Coast Ranges Orogeny about 1.8 million years ago. The rest of Canyon Country rests on alluvial fill and terrace deposits from the last few hundred thousand years. Parts of the hills in the Canyon Country area are composed of the Mio-Pliocene Towsley Formation and the Pliocene Castaic Formation. These are mostly marine in origin and are fossil bearing. Whale, dolphin, and countless shells can be found here.

Oil is not found in the Soledad Basin, but is found in the Ventura Basin. The boundary between the two basins is the San Gabriel Fault. This boundary can be seen along Highway 14 south of Golden Valley Road where a large number of oil seeps exist alongside the freeway.

Many fossils have been found out here as well. South of Highway 14 near Via Princessa, the Towsley and Castaic Formations outcrop offering many fossil finds. Everything from shells to whale bone have been found in the hills around here.

Rivers and Drainage

The Santa Clara River is where all the streams drain to in the Canyon Country area. Mint Canyon Creek has its confluence with the Santa Clara River near Solemint Junction. That creek, while dry most of the year, drains a large portion of the mountains to the north. The Santa Clara River generally runs from east to west through the valley. In Canyon Country, it runs in Soledad Canyon and follows Soledad Canyon Road. Only a few miles have manmade levees, making this river the last remaining wild river in Los Angeles County. Shown below, the Santa Clara River runs by the main part of Canyon Country.

Faults and Folds

Most of the folds are aligned north to south in this area. They were formed when the mountains uplifted and the region was compressed. Some of these folds have small thrust faults which are inactive. Fautling is visible in a road cut on Soledad Canyon Road just east of Sand Canyon Road. A result of the folding and subsequent erosion, landslides have formed in parts of the Mint Canyon Formation. These slides, known as dip-slope slides, are formed when the strata is dipping at the same angle as the slope itself. A few of these slides are visible east of Sand Canyon Road on Soledad Canyon Road near Rue Entree and Flowerpark Drive. Other larger landslides are to be found in the vicinity of Antelope Valley Freeway (SR- 14) near Golden Valley Road. There, three major slides exist. One, the Freeway Earthflow, causes the Antelope Valley Freeway (SR-14) to become bumpy between Cedar Valley Way and Golden Valley Road.

• Description of the Mint Canyon Formation