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Slip
& Slide |
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Gravity
can move large masses of rock that arch over spaces forming caves.
These can be landslides of rock slabs or rubble, or the slow creep
of gradually sagging clay beds. |
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Step
1. A stream winds its way along cracks in a boulder-strewn landscape.
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Step 2. In time the stream cuts a deep slot canyon through the rocks.
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Step 3. Boulders on the canyon rim tumble into the slot canyon, roofing
it over.
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Step 4. Additional boulders accumulate further roofing over the cave.
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Erosion
sets the stage for the formation of caves of this sort. Streams
and glaciers erode steep-sided canyons in various rock types. In
hard rocks like granite, huge boulders can bridge narrow canyons,
and erosion can continue beneath. In larger canyons, spaces in a
jumble of boulders form talus caves. With canyons cut in sedimentary
rock, layers of rock can slip and arch over the canyons, or landslides
can fill the canyons only to have water erode a mud cave underneath. |
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View Slide Show
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Return
to California Underground Realms |
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