Beach Processes and Geology of Southern California
September 30-October 3 1994
We thought we'd have a difficult time convincing the Department to send us to the beach, but it turned out that a real scientific opportunity came our way. The scientific planning group for an advanced Mars orbiter mission (possibly part II of the Pathfinder program) wanted to know what kind of resolution would be needed on an orbiter to see beach features that may be interpreted as ancient shorelines. We examined beach formation processes and their manifestations on the shores of Southern California to determine the features characteristic to shorelines and the scales on which they occur. We determined that one-meter resolution was probably fine to identify major shoreline features. Plus, we got to splash in the surf, too.
The features we examined ranged from fine laminae in beach sands to large estuary systems, and everything in between: swash marks, ripples, beach cusps, sand spits, wave-cut platforms, offshore bars, lagoons, and submarine canyons. The physics of breaking waves, rip currents, beach profiles, grain movement, tides, and wave generation were all studied. We discussed ancient shorelines as well--Lake Bonneville in Utah and the possibilities on Mars and Titan. Related to the beach environments were talks at the Channel Islands and Santa Barbara Harbor.
We didn't miss the inland geology, though. Highlights of this part of the trip were the Portuguese Bend Landslide near Palos Verdes Estates and the natural tar occurring on the beaches at Carpenteria. Other geology included discussions of the Sentinel volcanic field in Arizona and the regional geology of Los Angeles. The trip concluded with a stop for date shakes at the fabled Shields Date Farm in Indio, CA.
This is Silver Strand Beach in San Diego, as we prepared to kill all marine life with potentially carcinogenic Rhodamine-G dye tracer.
One small crack can be the precursor to one huge landslide. This is the Palos Verdes Estates landslide south of L.A.
|Natural tar oozing from the ground.
Oil rigs line up along the fold axis of the petroleum deposit off Carpenteria State Beach.
|Andy, Ellen, and Zibi attempt to eat field-trip ice cream while Doug attemps to eat his flashlight.|
|The obligatory stop for a wrecked vehicle ("don't check the oil when the motor's running!")
--also a convenient ice run.
|Will visits with a farmstand pig ("here, have this...pineapple!).|
|Overlooking historically troubled Santa Barbara Harbor.|
|"...these blackest of black dates are red when they're green."
From The Sex Life of the Date, Shields Date Gardens.