Friday, August 26, 2011

Accrectionary Wedge #37 - Sexy Geology

Lockwood put out this call for  Accretionary Wedge 37 on July 27.  Its hard to believe the deadline has arrived.  Normally I like to do these things early, but I've been having major computer troubles ever since Yahoo and Mozilla firefox has had updates which ended up crashing my computer.  The computer has been in the shop and I just got it back today.  Just in time so I could get something out for the wedge.


Call for Posts, AW #37: Sexy Geology

July 27, 2011 by lockwooddewitt
This month’s Accretionary Wedge asks the titillating question, “What is ‘Sexy?’”  Hint: we’re not talking Victoria’s Secret.
I mean geology that makes your heart race, your pupils dilate. Rocks and exposures that make you feel woozy and warm. Structures and concepts that make your skin alternately sweaty and covered with goosebumps. Places you’ve visited, read about, or seen photos of that make you feel weak-kneed, and induce a pit in your stomach.
Click over to read the full description of what this month’s topic is (and is not) meant to entail. If you have a post to submit, please leave a comment and link either here or at the original call for submissions, so I can find it when I go to assemble this edition.

   When I saw this there were a lot of different places that came to my mind.   But then I narrowed it down to one.  But after reading this Roadtrippin'  post by Dana  and seeing the pinnacles at Crater Lake with this Volcanic ramblings part 1 teaser @ Outside the Interzone post at Lockwood's I'm torn between which one to choose. Now he's added even more pictures of those pinnacles at this post what-is-sexy-geology that make me even more titillated .  With both of these locations I have never been to, but just the thought of them sets my heart racing. Decisions, Decisions.  I'm in such a corundum. Which one to choose.
   So my two choices are both in U. S. National Parks.   I've read about them and have heard people talk about them a lot.  Everything I hear about them just makes me want to go all the more so and gets me so excited just thinking about them.  The two are BIG BEND NATIONAL PARK, TEXAS. and  CRATER LAKE NATIONAL PARK, OREGON. The one thing I've noticed about both of these locations is that they have unique volcanic structures associated with them.

   I studied Crater lake in school only when we studied it, the instructor was teaching us about 'caldera's' and said it should be called 'Caldera lake not Crater'.  That caught my interest and ever since then I've wanted to see it.  To me it was pretty neat thinking the lake formed in the center of a volcano. While Big Bend I never heard about until I got out into the workforce with a petroleum company.  But its Big Bend that's won the coin toss, which is good because I know Lockwood and Dana Hunter are going to do such a good job with Crater Lake.

  If first heard about Big Ben when I went to work for Marathon Oil.  On the 1st or 2nd day on the job I asked my boss a simple question.  "How did Marathon get its name?'  I was expecting an answer along the lines of something to do with Marathon running or something about Greece at Marathon  or events relating to the battle and the legend of Pheidippides.  The answer surprised me.  He said they were named after the Marathon mountains in Texas.  He then clarified his answer by saying that was the area where the Old Ohio Oil company found a lot of its reserves that lead to the company being able to be the size company it was at the time.  He then told me if I wanted to find out more about the company I should read the book "Portrait in Oil" by Hartzell Spense (1962). Its all about how Ohio Oil became Marathon.  (It took a while to find a copy of the book but I finally got one and read it).
   After I had talked with him I was curious about the Marathon Mountains.  I went to my Rand McNally Road Atlas of Texas and looked for them.  Well Texas is a big state and I couldn't find the Marathon Mountains on them.  So I went back to my boss and asked him exactly were they were.  He said they were part of the Permian Basin in west Texas, just north of the Big Bend National Park, where the Rio Grande river dips down into Mexico. My boss was the main geologist for that office and he just loved geology.  He then said something that got me intrigued about the area - he said 'Now that's a park for a geologist if there ever was one.  It's got a little bit of everything there.  You should go there sometime.  If you ever end up in the Midland office you most definitely will get a chance to see the park then.'
   I went back to my office to find the Marathon mountains- I couldn't find mountains but I did find the Marathon basin and the town of Marathon just like he said it was--just north of Big Bend National Park.  Since it was such an important area to my company I felt like I needed to learn as much as I could about the area as possible.
  I thought I would make an weekend trip so I could see Big Bend for myself.  I looked my map of Texas and realized it was about 750 miles away.  I knew from driving to other areas that it would be a two day trip just to get there and another two day trip to come home.  Also I knew I would want to spend as much time as possible there once I got there. I would need a whole week of vacation just for that trip (and I wouldn't have that for at least one year)  Driving was out.  So I looked into flying there.  That was out too because it is in west Texas and there just is not much there.  The closest place to fly into is El Paso but you still have hours of driving to get there.  The price of the flight was outrageous too, neither location is popular destination spots and it just about made me pass out when I saw how much it was.  So flying was out also, and all I was left was to dream about it and add it to my bucket list of things to do before I die.
   So whenever I heard of anyone going to the area I would ask them to tell me all about it.  Every time I heard anyone talk about it, it just would make me green with envy with wanting to go there. One geologist friend said to me 'imagine a volcano, that is dormant.  Now imagine a river cutting it in half and you can traverse through that volcano.  It was the most incredible thing he's ever done.'  He must have been talking about the Chisos Mountains in the center of the park.
  Another friend that went there is an artist and she said it was an incredibly beautiful place to visit.  It gave her a lot of inspiration just staying there. She really felt like she was in a desert when she went there.  She liked the way it was so remote and she could get back to nature.   I found this very interesting because I love places that get me back to nature.

   While I was with Marathon I would very occasionally come across some of the electric logs in that area that was north of the park and other areas associated with the Ouachita Orogeny.  It was highly faulted with thrust fault from the Ouachita Orogeny. Imagine that during the Paleozoic Era there being an deep ocean where shales, limestones, chert and novaculite were deposited.  The chert and novaculite have a very distinct characteristic look to their formations and make it very easy to map over large areas because they were so massive since they were in the deep ocean.  It would blow my mind to see these same sequences layer one on top of each other over and over again.  Each layer was there because it was thrust on top of the other when the northern continent collided with the southern continent to from one huge land mass.
    In the book 'Geology of National Parks, 6th ed' by Ann G. Harris, Ester Tuttle & Sherwood D. Tuttle (1975/2004) Chapter 53 pgs 791-804 Big Bend National Park, they talk about being able to see some of this in the northern part of Big bend at the Persimmon Gap area.  In fact not only do you see the thrust plates of the Ouachita Orogeny but the effects of three Orogenys.  As they put it 'The Paleozoic rocks in the thrust slices are the result of the Ouachita orogeny.  Later, during the Laramide orogeny these rocks and their Cretaceous cover unites were altered by overthrusting.  More recently , the rock unit have undergone extensional faulting due to Basin & Range deformation. (Tauvers and Muehlberger 1988  Persimmon Gap in Big Bend National Park, Texas; Ouachita Facies and Creatceous Cover Deformation in a Laramide Overthrust. Geological Soc. of America South Central Sec, Centiennial Field Guide v.4 p 417-422. )
Just imaging that boggles my mind.- thrusts upon thrust then normal faulting also.  How they ever figured that out must have taken an incredible amount of time and imagination.  Now I want to go see if their interpretations are reasonable.  (I bet it is just from the seeing the subsurface stuff that I have seen).
   Also what I keep on thinking about is here we have sedimentary rocks that must be changed into metamorphic rocks.  Not once but twice- I'm sure there has to be some pretty unique geologic features associated with that.
  Then it dawn upon me that the Big Bend park has all three rock types: sedimentary, metamorphic and igneous.  What could be more exciting to a geologist than an area where you can observe all three types.  Not only that the rocks come from three distinct Eras: the Palezoic - shelf to deep ocean; The Mesozoic with Cretaceous formations that are transitional, shallow marine deposition, to the top formation (Javelina Formation) that is non-marine deposition complete with dinosaur bones (pterosaurs) and silicified wood. And finally the Cenozoic with igneous intrusions, volcanic ash, hydrothermal mineralization and normal erosion, deposition feature. I could go on about other things it has like anticlines and canyons but I think you get an idea what the place is like.
   Talk about a complex area!!!  I would have been happy to go there just to look for dinosaur fossils in the Javelina formation.  It's a good thing its in a national park and you can't gather samples there otherwise I would have figured out a way to get there a long time ago.

   To me this place seems to have it all, and that is why I muse upon Big Bend being such a geologically sexy place to visit.   

Oops I forgot to add the link for Big Bend National Park info it's here.