Page 3 - stitt1981

Canyon Megabreccia but prior to deposition of the Mint Canyon

Formation The San Gabriel fault became active after deposition

of the Mint Canyon Formation in late Miocene time The San Gabriel

fault exhibits right-lateral separation of approximately 60 kilometers

on the Mint Canyon and older formations, approximately 30 kilometers

on Violin Breccia and Modelo Formation, and about two kilometers on

the Pico Formation San Gabriel fault "CIi ('p) and Castaic Hills

reverse fault moved in late Miocene time and became inactive prior

to deposition of the Pico Formation. The Charlie Canyon antidli.ae,

Charlie Canyon syncline, Castaic anticLine, and Ridge Basin syncli.ne

were formed in the Castaic Formation prior to deposition of the Saugus

Formation The Saugus is deformed by (1) folding which produced

the Dry Canyon syncline, Dry Canyon anticline, Townsend syncixie,

Lonia Verde anticline, North and South Hasley Canyon synclines, and

Oak Canyon antacline, (2) reverse faulting on the south-dipping Hasley

fault; (3) normal faulting in eastern Castaic Hills oil field; (4) normal

faulting on the San Gabriel fault. The San Gabriel fault may also

offset Quaternary aUuvium by normal separation in Castaic Creek.

Geomorphic evidence suggests continuing movement on the San Gabriel

fault, but the nature of seismic activity on the fault is still unresolved.