The Naked Scientists

The Naked Scientists Forum

Author Topic: How reliable are present rock features as a guide to past geology?  (Read 1485 times)

Offline OokieWonderslug

  • Full Member
  • ***
  • Posts: 93
    • View Profile
I was told once (I think it was on this forum) that today's topology has nothing to do with past topology. I took that to mean that things do not erode and expose previous landforms as they were before they were covered.

I was also told that there is a missing 5 miles of sediment in the Carolina piedmont and coastal plain.

If that is so, then why does it seriously appear that the coastal plain and the border area with the piedmont is ocean bottom and a shore line? If you follow 250ft asl it looks like it was a beach. It looks just like either the ocean lost 250ft of water or the area was raised up that amount.

I mean, how is it possible that erosion would so perfectly erode away all of that dirt and rock and leave such a perfect representation of the previous ocean bottom? Could it be the ocean was higher recently (geologically speaking) and the created landform is yet to erode?
Or could the area be subject to some sort of tectonic uplift? I have read that there was a period some 5 million years ago when the Uwharries experienced uplift and another 25 million years ago for the Appalachians. Could whatever event that caused the uplift have caused the sea bed to raise 250ft?

Or is the whole "65 million year old sea bed eroded out of 5 miles of sediments" thing orthodoxy and set in stone so to speak?
« Last Edit: 08/03/2014 15:03:40 by chris »


 

Offline OokieWonderslug

  • Full Member
  • ***
  • Posts: 93
    • View Profile
Maybe all the ice melted everywhere just before the last ice age and sea level rose 250ft? Like it is melting now? I have read that if all the glaciers and ice caps melted it would raise sea levels 250 ft. Is that what happened?

We can't ignore this. It is too obvious to not see. Anyone with Google Earth can see it instantly. So what is the reason? Is it erosion of miles of sediments uncovering an old ocean bottom or the remains of the last time all the ice was gone?

Darn it, I am trying to make sense of this area and all I get are crickets when I ask a question. And this seemingly is the most active geology forum on the net. There is no where to discuss this stuff it seems.
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1338
  • Thanked: 5 times
    • View Profile
OW, the coastal plain-Piedmont contact was a shoreline at one time.  Which is why the "fall line" exists.  Don't have time to delve into the particulars right now, but will revisit this in more detail later if someone else doesn't beat me to it.
 

Offline Bass

  • Neilep Level Member
  • ******
  • Posts: 1338
  • Thanked: 5 times
    • View Profile
In the meantime, I suggest you check out the following website http://csmres.jmu.edu/geollab/vageol/vahist/16pghisH.html
This is a very readable website with information on the geologic evolution of Virginia (and surrounding areas) that should give you all sorts of information.  Put together by some folks at James Madison University.
 

Offline Bill S

  • Neilep Level Member
  • ******
  • Posts: 1802
  • Thanked: 11 times
    • View Profile
Andrew Alden might be able to help.

http://geology.about.com/
 

The Naked Scientists Forum


 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums