| Actual Image
Reading the Rocks (48)
Silke
![Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 727 W: 98 N: 1694]](http://i1.treknature.com/misc/g-g-g.gif) (5406) | The coast of California is a wonderful place for a bit of natural history, which I hope makes up for the heaviness of the weather in this shot. When I arrived that afternoon, the rain had already begun and would continue for a few days, though I was so happy to breathe the warm sea air that it never dampened my spirits one iota :)
The tilt of some of the foreground rocks that border the edge of Hazzard Creek suggests prehistoric subduction in this area (see my notes here). It appears be the classic fold and crumple formation that resulted when the Pacific Plate slipped under the North American Plate. The layer cake you are looking at is primarily limestone, which continues offshore and provides a fabulous habitat for abalone (Pearl Oysters).
Limestone is a sedimentary rock formed either by the deposit of chemicals or by the accumulation of shells from tiny sea creatures. Many invertebrate animals (animals with no backbones) take calcite (CaCO3) from sea water to construct their shells. When they die the shells drift down to the sea bed. If there is no mud or sand in the area, the minute shells gradually build up a deposit. The purest limestone is chalk but most contain varying quantities of mud or sand or other material. In the limestone here you can clearly see how the sediments have built up on layers over time, with layers of other material in between.
You can also see how soft it is by the way wave action has eaten small caves into it. Once the fissure is created, it is easy for the water to pound into the opening and wear it away even faster. Since we also have a small river (or a large creek) making its way down to the sea here, there is additional erosion created by the creek waters at flood times. At this moment, the waters are quiet and keep to a fairly narrow channel, but when it is in full flood, the waters rush against the cliffs here and add to the eroding effect of the sea water waves.
These caves are no barely head-high but eventually will becoming higher and deeper. In Great Britain, the famous King Arthur cave in the cliffs at Tintagel was created this way. And caves like this have historically been superb hiding places for the treasures of pirates and rumrunners. Caves are wonderful places for the imagination to run free.
PP: Minor cropping to straighten the horizon so that the Creek still runs downhill :)
Thanks for your visits, your critiques and your time & have a super Labour Day Weekend
(And I hope you’ll be back for a much prettier bit of landscape next week, when I take a look at the intriguing Morro Rock, just a few minutes north of here.) |
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