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https://hdl.handle.net/11681/25409| Title: | Heavy minerals in beach and stream sediments as indicators of shore processes between Monterey and Los Angeles, California |
| Authors: | Judge, Charles W. |
| Keywords: | Heavy minerals Littoral drift Sand |
| Publisher: | Coastal Engineering Research Center (U.S.) |
| Series/Report no.: | Technical memorandum;no. 33 |
| Abstract: | Abstract: A study of heavy minerals along the California Coast was made at the Coastal Engineering Research Center (CERC) as an adjunct to the Radioisotopic Sand Trace(RIST) and the Littoral Environmental Observation (LEO) programs of the Center. Sand samples taken at the waterline during various times of the year were supplemented by samples from the offshore zone and the rivers heavy minerals in the 63-125 micron fraction of the samples were identified by optical techniques. Five heavy-mineral provinces were identified: 1) a northern Hornblende province from north of Monterey Bay to Piedras Blancas Point; 2) a northern Augite Province from Piedras Blancas Point to Avila Beach; 3) an Epidote province from Avila Beach to Ventura; 4) a southern Augite Province from Ventura to Palos Verdes Point; and 5) a southern Hornblende Province from Point Fermin south. The ratios of the less stable augite and hornblende to the more stable garnet and zircon indicated a definite southward littoral transport north of Point Conception. The increase in grain sizes and in augite and hornblende content south of the input from the Ventura and Santa Clara Rivers indicated a southward net littoral transport there. Similar trends could not be found between Point Conception and Ventura. Because of possible multiple sources for augite and because of reversals in the littoral transport, heavy minerals are not definitive indicators of littoral drift along beaches from Point Conception to Ventura. However, coupled with other evidence from radioisotopic tracer surveys, historical surveys, and dredging projects, it is reasonable to conclude that, although Point Conception-Point Arguello may act as a partial barrier, some sand moves south and east around them. |
| Description: | Technical Memorandum |
| Rights: | Approved for public release; distribution is unlimited. |
| URI: | http://hdl.handle.net/11681/25409 |
| Appears in Collections: | Technical Memorandum |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| CERC Technical Memorandum No 33.pdf | 8.89 MB | Adobe PDF |  View/Open |