Geologic map of a part of the Tick Canyon area, Los Angeles County, California: Supplement 2 from "The Vasquez series in the upper Tick Canyon area, Los Angeles County, California" (Thesis)

The Vasquez series of probable Gligocene age consists of interbedded sedimentary and basic volcanic rocks, and is well exposed in the vicinity of Tick Canyon, northern Los Angeles County, California. In this area the section is 4810 feet thick. The sediments are nonmarine deposits that were laid down under alternating lacustrine and fluviatile conditions in a semi-arid climate. The basic igneous rocks are extrusive, and comprise flows, flow breccias, and minor tuffs. The beds occur in a sharply-folded syncline with a gentle southwesterly plunge. They are in fault contact with a much older, pre-Cretaceous complex of crystalline rocks, and are nonconformably overlain by the Tick Canyon formation of Lower Miocene age. Sets of northeasterly- and northwesterly-trending faults cut the syncline. Movement along these faults was predominantly strike slip. Those of the northeasterly-trending set show much the larger displacements, and blocks on the southeast side are offset to the north with respect to blocks on the northwest side. Faulting appears to have been contemporaneous with the later stages of folding from pro-Tick Canyon to post-Mint Canyon time. Vertebrate and invertebrate fossil remains were found in several beds, but none proved diagnostic as a means for dating the Vasquez series. Mining for borate minerals was once an active industry in the area. Many gold prospects are present in the area underlain by crystalline rocks. Major faults in the area are water-bearing in places, and have important significance in regard to water supply.