Geologic Map of a Section of the Palos Verdes Hills: Supplement 1 from "Geology of a section of the Palos Verdes sea coast. Geology of a portion of the Adelanto Hills" (Thesis)

Geology of a Section of the Palos Verdes Sea Coast: The area in which this work was done is located in the San Pedro Hills Quadrangle. It can be reached by following the Roosevelt Highway south from Redondo, California, then following the branch off this highway along the coast. The area begins about one eight mile south of San Vicente Lighthouse at Long Point, extends southeast for a little over four miles along the coast. The area includes the sea cliffs along the ocean. It does not constitute a true area because no extension back from the coast was studied. The area was investigated on foot, there being only two places accessible by car, one at Abalone Cove and the other at Portuguese Bend. Geology of a Portion of the Adelanto Hills: The Adelanto Hills are a low range of folded limestone hills, situated about five miles northwest of Adelanto, California. The limestone is a dark blue, finely crystalline banded type, which has been hydrothermally altered in places to a white crystalline limestone, or to a fine-grained, highly altered brown limestone. The alteration is indistinctly associated with faulting and minor intrusions in the area. The main igneous body in the area is a large granodiorite body that apparently has been faulted into its present position. A complementary association of a fine-grained dark intrusion and numerous pegmatite dikes occur in the northwestern part of the area. Several large, light colored acidic dikes intrude the limestone, and their relationships to the other intrusions cannot be determined. The area is cut by a large fault tending N65 W and by numerous smaller faults trending about N20 W. The structure on either side of the main fault is roughly parallel. Mineralization of the area is mainly a contact-metamorphic type, containing lead, zinc, and silver. Considerable oxidation in the area has occurred, resulting in some secondary enrichment, especially of silver. Some scheelite is mined at the present time from a contact zone between porphyry and limestone