#Fold mountains
>>>Until, of course, there is deposition on top of the stubs, as there is
already in GA and AL where the southern range disappears under the Mesozoic.
Should that area ever be uplifted and subsequently eroded, newly re-exposed
faults and folds will once again provide relief.<<<
I'd think that if erosion proceeds to the point of actually flattening out the
countryside and the area is then uplifted again, new drainage patterns will
develop away from the center of the uplift. There may certainly be traces of
the former drainage pattern. What makes me sceptical of the Appalachians as a
reuplifted range is that the major drainage patterns either follow the folds
or, in the case of rivers like the New and Susquehanna seem to predate the
folding entirely. The drainage is what you'd expect to see in a folded mountain
range, not a folded range that has eroded, then re-emerged.
There is also the question of why No Middle or Lower Mesozoic sediments occur
around the ranges. There are, not suprisingly, some sedimentary layers in the
Triassic Jurrasic Rift Valley deposits along the East Coast, but no particular
evidence (that I'm aware of) that the sediments originated in the Appalachians.
I really can't see any hard evidence that the Applachians are older than the
Early Cretaceous.
The whole thing looks kind of like bending the facts — moderate erosion —
maybe 100,000,000 years worth to fit modern theory that requires the mountains
to be three times that old. Don't know why this bothers me. I don't really
much care how old the Appalachians are.
Of course I don't know enough about geology (other than what sediments are
found where) to even qualify as an informed amateur so what do I know?