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Tuesday, May 6, 2014

Fast and Slow Rates of Tectonic Change: New Zealand and Arizona

     I received an alert from The New York Times today with this "breaking news" about climate change. Temperatures rising slightly less than 2 ° F are certainly cause for concern but, for most scientists it is hardly breaking news. The data are important, though, especially the possible projected rise in mean temperatures by up to 10 °F by the end of this century:

        CLIMATE CHANGE REPORT

    As a focus today, I'd like to compare the relatively quickly-changing tectonic geomorphology of New Zealand to the much slower-changing tectonic geomorphology of Arizona.
Tectonic geomorphology involves the interplay of surface features with underlying tectonics.

     In this geologic map of New Zealand, rates of up to 5 mm uplift per year are noted in red:




      Areas of rapid uplift are marked by active faults, seismic activity, waterfalls, and newly developing stream systems:





     New Zealand sits at the junction of the Australian and New Zealand tectonic plates and displays the features of a rapid convergent plate tectonic zone.

      In contrast, Arizona sits within the North American plate, rather than at the convergence of two plates. The fluvial (river) geomorphology is well developed and integrated. The landscape has had long periods of time to adjust to ancient fault scarps creating well-developed alluvial fans:


     One of the most interesting parts of tectonic geomorphology to me is that features like alluvial fans may also mark places of more rapid uplift, where the alluvium is adjusting to more active uplift as in here in Iran:



     But, back to climate change (you knew I'd get back there, right?), the increased overall temperatures, torrential downpours, and periods of drought are all intimately connected to this skin of our earth. The climate we are changing will inevitably affect the tectonic geomorohology as landscapes adjust to the wide swings in temperature and rainfall.

      Looking forward to your thoughts on this interplay of climate and tectonic geomorphology, all you alluvial fans!

Tectonically,

Word Woman (aka Scientific Steph)


P.S.

Mid May in the Colorado Mountains:







24 comments:

  1. SS,

    When we talk of “uplift,” as in the New Zealand map, does that mean the red areas are 5 mm higher in elevation? If so how are those relatively small increases measured?

    A question I’ve never asked myself: How are waterfalls formed? Obviously abrupt drops in elevation are involved. Were these the result of earthquakes? Or what? My impression is that most U.S. rivers have no waterfalls (Mississippi, Missouri, Chippewa ;-) except those created for hydroelectric power. Was the river featuring that beautifully cascading waterfall at one time just a run of the mill river (that perhaps ran a mill)?

    The alluvial fans are “gorge-ous.” My MW Collegiate 10th dictionary defines them a bit abstrusely. (Using the word “abstrusely” is a prime example of abstrusity!) They are dry, I gather, vestiges of rivers that suddenly have multiple options as to which path to take, so they take them all, kind of like tributaries in reverse.

    Are alluvial fans a little like fossils of rivers that dried out?

    Did I just dream this, but in “The Music Man” wasn’t the hometown baseball team called the River City Alluvials? Lots of Alluvial fans among those denizens. Alleluvia!

    LegoLuvial

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    Replies
    1. Lego, the 5 mm uplift is a relative measure of change. GPS is used to measure the difference in elevation change. 5 mm is pretty dramatic in one year.

      The main thing to know about waterfalls is that they are signs of a young river. They can be formed by faults, at edges of glacial hanging valleys or by differences in resistant vs. less resistant rock type. With time (millions of years), the rivers become more like the rivers in the center of the US--slowly meandering behemoths. There are some natural waterfalls in New England (right on the Smith campus) and plenty in CO. The Frank Lloyd Wright House at Falling Water also comes to mind.

      The alluvial fans splay out from a higher elevation to a lower one. The water does, indeed, go everywhere in a triangular shape.

      Hmmm, maybe like reverse fossil rivers...

      Alleluvia indeed!

      Great questions, Lego.

      Delete
  2. Thanks, SS.

    I a-lluvi-all your geo-logical answers.
    Lego

    ReplyDelete
  3. And I a-lluvi-all that you make me think about stuff that I take for granted as well as thinking of new ways to see things geologically, Lego.

    The alluvial fans in AZ are really quite amazing. Have you seen them?

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  4. Some of the text above reminded me of Sally Rand, a well developed ancient alluvial fan dancer, known for dropping scarps in early films. (Sorry, my fault.) Another geography tie-in: her stage name was reportedly inspired by a Rand McNally atlas, though I'm not sure of the connection.

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    Replies
    1. I don't see why Ruth on the other blog thinks we get off topic.

      Yes, Sally Rand and alluvial fan dancing was a good way to get "scarp" into the conversation. You name dropper, you! Hope that comment is protected by your no-fault insurance.

      Delete
    2. Dr. Suess's unpublished geologic books for kids: Harp on Scarp and One Scarp, Two Scarp, Red Scarp, Blue Scarp.

      Delete
    3. Ridiculous!

      Any thoughts on this very confusing article from NPR's Robert Krulwich today? The opening illustration and text about combining science and art make no sense to me...and it goes on from there:


      http://www.npr.org/blogs/krulwich/2014/05/07/309828787/draw-my-left-no-no-my-other-left-a-hidden-bias-in-art-history-revealed

      Delete
    4. Krulwich is usually better than this. That stuff about "But — as you probably know — your right brain operates mainly through the left side of your body. So when you look at someone's face, your right brain pulls in information from the left of your visual field" might be true in Mike Gazzaniga's commissurotomy patients (whose corpus callosum was severed), but the rest of us have hemispheres that talk to each other.

      Delete
    5. Indeed! I was surprised that much of Krulwich's post was indeed posted as it contradicts itself several times...

      They aren't making (having) editors like they used to.

      Delete
  5. Breaking news: Stanford U.'s $18-billion endowment fund has divested of all coal stocks.

    ReplyDelete
    Replies
    1. Remind me what Leland Stanford's Southern Pacific and Central Pacific Railroad locomotives ran on?

      Delete
    2. Cole Porter songs?

      Oh, the irony (carbony?)!

      Delete
  6. I heard on the radio today some politician or someone saying that “the coal industry was being killed” by one thing or another. (Ironic use of the word “killed.” Those favoring capital punishment for mass murder might argue that the coal industry should be killed!)

    My efforts to google the quote failed but it likely referred to a Supreme Court ruling documented here.

    jan,

    Sally Rand is a fine name, but Sally McNally has a nicer ring to it.

    LegoRiverFanDanceFan

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  7. Lego, thanks for the link. Interesting spot.

    As to Sally Rand (nee McNally), she seems less alluvial and more fluvial (pronounced floozie-al).

    Stream of Consciousness River. . .

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  8. PEOTSites,*

    Today I am launching my first blog, a puzzle blog called Puzzleria!.

    I believe my Puzzleria! blog will appeal to followers of PEOTS: Intellegent people who love both science and words. Puzzleria! will serve up a steady diet of both word puzzles and number puzzles. I will try to sprinkle in a dash of science, also, as in the inaugural blog’s second puzzle on the menu.

    Our own Scientific Steph, creator and maintainer of this PEOTS blog (Partial Ellipsis Of The Sun), gave me invaluable assistance and encouragement in the creation and launch of Puzzleria! Thank you, Steph.

    If you like my Puzzleria! blog, please follow, participate in, and tell others about it. Thank you, PEOTSites!

    * PEOTSites = Partial Ellipsis Of The Sun followers and contributors… and “peotsite” is the name of a mineral that will in the future be discovered by Scientific Steph.

    LegoLambda

    ReplyDelete
  9. Helix is very cute. (Assuming that's Helix the (wonderful, wonderful) Dog in the photo.)

    ReplyDelete
    Replies
    1. Paul, it is Helix, aka Maizie. Thanks. Far different weather in the hills this weekend though.

      Canines, felines, muskrats your way?

      Delete
    2. Maizie, of course! You mentioned that somewhere before, and I forgot.

      Lots of chirping birds this morning, but I didn't notice any mammalian activity, except, of course, the (yawn) human kind.
      I don't know if I've ever actually seen a muskrat:

      Creation of the World (Blackfoot)

      "In the beginning, all the world was water. One day the Old Man, also called Napi, was curious to find out what might be beneath the water. So he sent animals to dive beneath the surface. First duck then otter, then Badger dived in vain. The Old Man then sent Muskrat diving to the depths. After a long time muskrat rode to the surface holding between his paws, a little ball of mud, and then blew upon it. The mud began to swell, growing larger, and larger, until it became the whole earth. Then the Old Man made the people."

      Delete
    3. Thanks for the muskrat tale. I have seen a couple of them but had no idea their breath was that powerful!

      A friend is growing out his mustache so we've been calling the couple he is a part of "Muskrat Susie, Mustache Sam." That's where the muskrats came from in this part of the world. . .

      Delete
    4. I think a significant percentage of muskrats do not floss. I may be wrong about that.

      Delete