Five distinct heavy mineral assemblages are found in late Cenozoic and modern sediments along the central California coast. Nine heavy mineral provinces distributed in the central California Coast Ranges and adjacent continental shelf are formed by these assemblages. They are: (1) hornblende-sphene, derived from granodiorite and quartz diorite rocks; (2) hornblende-garnet, derived from mixed granitic and metamorphic rocks; (3) glaucophane-jadeite, derived from Franciscan rocks; (4) augite, derived from Cenozoic volcanic rocks; and (5) hornblende-augite-hypersthene, derived from volcanic and plutonic rocks. These assemblages are based on nonmicaceous, nonopaque minerals in the sand-size fraction of sediments. Micaceous and opaque minerals differ greatly in hydraulic properties from most heavy minerals. They are generally not indicative of provenance but instead are useful indicators of depositional environment.

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