Saturday, February 06, 2010

Discovery Park

I was just down here in November (
West Point) but the tide had been too high to let me visit the big landslide on the south side of the park. Today, the water was lower and we were able to get a good look at this complicated stretch of shoreline.

There's been plenty of recent sliding - maybe a combination of early fall rains and the recent high tides. The beach was littered with scraps of wood and there was little logic or pattern to the sediment on the upper beach - suggesting lots of fresh material, lots of sorting still to happen.
The large central portion of the slide was dumping large amounts of sand onto the beach and a raised band of deformed clay 20-30 feet out on the beach marked the toe of the active slide. The lower beach at the south end of the park is marked by a confused series of ridges or berms. They did not appear to be normal bars - maybe they reflect irregularity in the topography of the platform due to historic deep-seated sliding or otherwise messed up geology.

There was little mobile sediment in this southern area. Maybe it's an an indication of a sediment-starved beach. The historic source of material is the two miles of updrift, and unstable, shoreline now called
Perkins Lane (2007) - which has been largely armored for most of a century.

No comments: