kingwinner Posted October 1, 2005 Report Posted October 1, 2005 1) Graben and fault-block mountain are created by a faulted block moving up or down. But from definition grabens are flat horizontal valleys but fault-block mountains are not flat horizontal plateaus? (I think a block moving up should simply create flat plateaus...) This following figure is what I mean. Why the fault-block mountains are not flat while the grabens are flat? 2) How does a fold mountain look like and how does a fault-block mountain look like, in terms of appearance? I mean, how can I distinguish a folded mountain from a fault-block mountain? (I have seen pictures of both types of mountains, but honestly, I can't tell a single difference) I hope someone can explain to me! Thank you! Quote
Turtle Posted October 1, 2005 Report Posted October 1, 2005 1) Keep in mind the simple drawing is a gneralization. Erosion forms irregularities dependending on rock types. See 'angle of repose'.2) Where's Waldo? :Waldo: Quote
kingwinner Posted October 2, 2005 Author Report Posted October 2, 2005 edit to insert question on dome mountains Quote
kingwinner Posted October 2, 2005 Author Report Posted October 2, 2005 1) I see, fault-block mountains are perferentially eroded, thus they are not flat. On the other hand, grabens are lower so much less erosion occurs, so there are quite flat! But why plateaus (ie high land formed beside folded mountains instead of a fault block dropping) like the Colorado and Tibetan Plateaus are flat-topped? How is a plateau different from a fault-block mountain? 2) So fold mountains and fault-block mountains look similar that it is hard to distinguish...so how do people identify which mountains are fold mountains (e.g. Himalayas) and which are fault-block mountains (e.g. Sierra Nevada mountains in the US)? How do they know that? By examining rock layers? 3) "Dome mountains are the result of a great amount of melted rock pushing its way up under the earth without folding or faulting resulting in a rounded dome" (quote from web sites)How can this "without folding" be possible? When magma pushes rock layers upward, the rock layers above are deformed by bending, or in other words, folding...or else dome mountains can't be formed...can someone please explain why dome mountains are formed without folding? Quote
kingwinner Posted October 10, 2005 Author Report Posted October 10, 2005 Can someone clarify? (especailly for Q3, I don't get how rock layers of dome mountains are considered undeformed and unfolded...) Quote
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