Most people who drive through Jamestown and Sonora
see Table Mountain in passing but very few think about how it got
here.
Table mountain is an example of inverted
topography. Inverted Topography describes a formation that is a
mountain or hill that used to be a valley floor. An example of how
this happens is when a lava flow flows down a canyon and fills the
bottom and forms basalt. Then the sides of the valley are eroded
away and only the basalt is left, forming a plateau with inverted
topography.
Inverted topography is not to be confused with
sedimentary folding. With sedimentary folding the rocks are pushed
up from below the surface to form a topologically high point while
inverted topography is caused by erosion and volcanism.
To get credit for this earthcache email me the
answers to the following questions:
1. The GC code and name of this cache.
2. The number of people in your group.
3. Describe the two kinds of rock found in the area.
4. Tell me where each of them were when before the topography
changed.
5. Does the profile of Table Mountain support the inverted
topography theory?