The Naked Scientists
  • Login
  • Register
  • Podcasts
      • The Naked Scientists
      • eLife
      • Naked Genetics
      • Naked Astronomy
      • In short
      • Naked Neuroscience
      • Ask! The Naked Scientists
      • Question of the Week
      • Archive
      • Video
      • SUBSCRIBE to our Podcasts
  • Articles
      • Science News
      • Features
      • Interviews
      • Answers to Science Questions
  • Get Naked
      • Donate
      • Do an Experiment
      • Science Forum
      • Ask a Question
  • About
      • Meet the team
      • Our Sponsors
      • Site Map
      • Contact us

User menu

  • Login
  • Register
  • Home
  • Help
  • Search
  • Tags
  • Member Map
  • Recent Topics
  • Login
  • Register
  1. Naked Science Forum
  2. Non Life Sciences
  3. Geology, Palaeontology & Archaeology
  4. New Madrid a failed rift?
« previous next »
  • Print
Pages: [1]   Go Down

New Madrid a failed rift?

  • 2 Replies
  • 3533 Views
  • 0 Tags

0 Members and 1 Guest are viewing this topic.

Offline OokieWonderslug (OP)

  • Sr. Member
  • ****
  • 113
  • Activity:
    0%
    • View Profile
New Madrid a failed rift?
« on: 19/01/2012 04:18:03 »
I have read that the New Madrid rift is a failed rift. Then I read that it is still spreading at 1mm per year. I then did a quick calculation and found that at 1mm a year it is exactly as wide as it should be for it's age. So if it is failed, why is it still moving? And why is it as wide as it should be if it never stopped moving at that rate? Sure, it might be slow, but apparently it is still moving.

Granted, it is filling as fast as it is getting wider so it won't ever make an ocean.

But how can a continent that is being pushed at both sides be splitting apart both in New Madrid and in Nevada? How can it rift apart while being crushed together by both the Pacific and the Atlantic? Something smells fishy to me.
« Last Edit: 19/01/2012 04:22:48 by OokieWonderslug »
Logged
 



Offline Bass

  • Naked Science Forum King!
  • ******
  • 1385
  • Activity:
    0%
  • Thanked: 16 times
    • View Profile
Re: New Madrid a failed rift?
« Reply #1 on: 24/01/2012 04:16:11 »
Most active rifts are speading at rates of >2 cm/year.  From my dim memory, I think the New Madrid rift was active around 750 million years ago, then failed to tear apart the continent.  I believe it is called "failed" because the rift stopped developing and never truly split the continent.

Remember that tectonic forces are dynamic.  You're right that Nevada (or more accurately, the Basin and Range) is extensional.  This may have to do with rotation, especially with the San Andreas and Walker Lane motions- or may be a mantle phenomena associated with the Yellowstone hotspot.  Look up "back arc basins" for other examples of extensional terrains in compressive regimes.
Logged
Old enough to have grandsons
Slow enough to study rocks
Thirsty enough to build a pub
 

Offline OokieWonderslug (OP)

  • Sr. Member
  • ****
  • 113
  • Activity:
    0%
    • View Profile
Re: New Madrid a failed rift?
« Reply #2 on: 24/01/2012 16:14:47 »
But the New Madrid is still spreading at 1mm a year. It is spreading as fast as it fills with sediment which I read is more than a couple miles deep now. At that rate it will never form an ocean basin. Even if it spreads forever. So you're saying it is failed because it never spread fast enough to get ahead of sedimentation. That sorta makes sense.
Logged
 



  • Print
Pages: [1]   Go Up
« previous next »
Tags:
 

Similar topics (5)

Jupiter--a "failed star"?

Started by DocNBoard Physics, Astronomy & Cosmology

Replies: 14
Views: 12215
Last post 08/04/2006 19:23:36
by Ophiolite
failed universes?

Started by eternityBoard Physics, Astronomy & Cosmology

Replies: 0
Views: 1730
Last post 20/03/2014 12:13:54
by eternity
Why did Amplifier Lakes in the Rift Valley only undergo cycles every 800K years?

Started by SnowlessBoard Physics, Astronomy & Cosmology

Replies: 2
Views: 334
Last post 05/10/2020 23:34:38
by Petrochemicals
What's the lowdown on the asthenospheric dome that can produce rift valleys?

Started by whalejailBoard Geology, Palaeontology & Archaeology

Replies: 1
Views: 2555
Last post 19/03/2016 00:32:09
by evan_au
East African Rift Valley..pls advise

Started by Maverick27Board Geology, Palaeontology & Archaeology

Replies: 4
Views: 4571
Last post 13/05/2011 03:57:09
by Bass
There was an error while thanking
Thanking...
  • SMF 2.0.15 | SMF © 2017, Simple Machines
    Privacy Policy
    SMFAds for Free Forums
  • Naked Science Forum ©

Page created in 0.078 seconds with 39 queries.

  • Podcasts
  • Articles
  • Get Naked
  • About
  • Contact us
  • Advertise
  • Privacy Policy
  • Subscribe to newsletter
  • We love feedback

Follow us

cambridge_logo_footer.png

©The Naked Scientists® 2000–2017 | The Naked Scientists® and Naked Science® are registered trademarks created by Dr Chris Smith. Information presented on this website is the opinion of the individual contributors and does not reflect the general views of the administrators, editors, moderators, sponsors, Cambridge University or the public at large.