Quote:
Originally Posted by drumz0rz
On a serious note, how far down would they need to go below the sandy surface to reach bedrock?
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Contrary to what you might think, the surface isn't that sandy - certainly nothing like the Sahara or other sandy deserts. The geology of the area is mostly depositions of fossiliferous limestone and sandstone, formed when the area was under a shallow sea. A good analogue for Jeddah's geologic condition is Miami, where the compressed coral bedrock (oolite) is rarely more than 6 feet beneath the topsoil.
Edit: The analogy between Miami and Jeddah doesn't expand to Saudi as a whole. Florida is obviously flat, sandy and wet, covered with silt and sand runoff from the eroding Appalachians. The Arabian Peninsula, meanwhile, is arid, rocky and home to terrain both flat and mountainous. Jeddah also sits atop a thin sliver of land known as the Red Sea Rift Basin, formed where the Arabian and African continental plates shift against each other. That means oceanic basalt is somewhere in the mix, but I couldn't tell you where.