Ge11a Field Trip: Friday 10/26/01

First stop was Red Rock State Park, home of several large features boasting red and white layered rocks with many vertical columns. This is caused by pillaring, which happens when there is a top layer of relatively hard rock over a bottom layer of softer material - the top layer will not erode very much, and the bottom layer will mainly erode due to water dripping down the sides, creating columns.

Close up of a fault line. The direction of motion is not clear (nor was it very obvious on site.) Some people thought it was a normal fault.

Me, holding a sample rock, the coloration and striping of which got completely washed out by the bright sun.

An hour or so drive away is Red Hill (not pictured) and the Fossil Falls, which are the very interestingly-weathered remains of a long-ago waterfall. In the background are the Sierra Nevadas.

Geology students riddle the landscape, crawling through the large holes cut out by many years of erosion. The falls themselves are ~50 or more feet deep.

The origin of the surreal landscape can be seen in this small mound. Since the basalt which makes up the rocks is porous (you can see the small holes in the main rock), water and small grains of dust or sand easily sept into small cavities. Since the water was moving quite fast this close to the edge of the falls, the water and sand began to wear away at the cavities, as seen by the circular indentation surrounding a small central mound here.

Eventually the whirling sands created huge hollowed out areas, which would merge with other hollowed out areas to create very bizarre and twisted looking features.

Go to: Saturday or Sunday

Return to my home page