Monday, October 22, 2007

Big Bend Part 2: Geology

Don't let the title scare you away...I don't know much about the subject, so I won't go on forever about it! :) Again, I have a disclaimer.

1) I do not claim to have any recollection of any geology studies I may or may not have suffered through in school or at home (my dad was a geology major in his college days). So if I make a complete fool of myself by trying to recap what I did or didn't learn during this trip regarding geology, feel free to comment...or you can let me live in ignorant bliss.

Monday morning we got up at 6:30am in the DARK and cooked pancakes and eggs by headlamp. It was quite interesting, especially since the stove’s lowest setting was too hot for the pancakes to cook right. So Heather and I took turns holding the pan 2 inches above the burner instead of letting it rest on the burner.

This is what we were seeing (or not seeing).
Here we are with the flash so you can see us. :)

This is the MORNING sky - the sun is coming up!
We had planned to go to a “Geology for Dummies” tour led by Ranger Angelina Yost which started at 8:30am. By the skin of our teeth we arrived on time and started to be edjumacated about the geology of Big Bend National Park. And here is where my disclaimer will play a major role in my story.

Ranger Yost started out at the Panther Junction visitor’s center with comparing the timeline of the earth’s evolution to a 12 month calendar year.

I think the gist of the outline was that there was a Precambrian Era that would have taken up from January 1 through Christmas. Then there was a Paleozoic era that started at Christmas, followed by a Mesozoic era (I don’t recall when that started), and then the Cenozoic era which may have started on Dec 31st (which includes the Quaternary period that we’re in now). Heather may recall more details better than I do – Ranger Yost was good, but I think I must have been one of her “dumber” dummies because I still didn’t quite catch all of the terms that she was throwing out there.
Ranger Yost then told us what was happening geologically during these eras and started breaking down the eras into periods. There were deep seas in the Paleozoic era, then sedimentation occurred to create shallow seas and beaches started forming as land masses started moving, creating the Appalachian mountains. Dinosaurs were thrown in there somewhere (Mesozoic era??), and then they died and the Rocky Mountains were formed. Somewhere in there she mentioned a chocolate covered caramel bar which got my attention (surprise, surprise). It was to illustrate land pulling apart and stretching, which causes the middle part to sink in elevation while the ends stay tall. (I'll throw some pictures in here so you don't get bored, but I don't have explanations because I don't remember what she said about the geologists' theories for these formations).

Obviously I didn’t catch all of the details she was sharing, and I’ll admit that I wasn’t really paying attention that closely because I don’t agree with the “a billion years ago the earth was formed” timeline. I did find it interesting that the Appalachian mountains reach as far south/west as Texas, so Texas has mountains that are members of both the Appalachian mountain range and the Rockies Mountain range. I think most people think of the Appalachian Trail which stretches from Georgia to Maine, and figure that the mountain range starts/stops in those states, too. But according to the all-knowing geologists, “The Ouachita mountain belt extended from the Southern Appalachian region across the Mississippi Valley region, all the way across Texas into the Big Bend Region, and southward into Mexico.” Well I’ll be!

Once we got on the road, we were shown mountains that were formed by the erosion around intrusions (magma, or underground lava, that pushed through older rock but didn’t come out on the earth’s surface); and extrusions (volcanoes that blew up spewing lava). Laccoliths were pointed out, as well as dikes and volcanic domes (don’t ask me the definitions though).

The next part that got my attention was when Ranger Yost started explaining that over the past 10 years, geologists have changed their mind about how some of the mountains formed, and how old they really are. Apparently after Mt. St. Helens erupted, a lava dome started forming faster than geologists thought it could/should form. And a guy in Japan recorded a mountain “growing” in the 1940s, also proving that mountains can form a lot faster than geologists guessed. So now they think some mountains in Big Bend are actually volcanic dome, rather than intrusions that required millions of years of erosion to expose.

This map was made in the 60's by a geologist riding on a horse. So Ranger Yost said that part of it (encompasing the harder to reach mountains I believe) is wrong. Yet it's still the only map that the Park has. She mentioned that there is a project being proposed to create a new map using modern technology (GPS, satellite, etc). But for now, they have to use this old map. Incredible!
I had to bite my tongue (hard) to keep from asking about how geologists thought a world-wide flood that would create a water covered world for a little less than a year, which would recede in a matter of 2-3 months would affect their geologic timeline theories (see Genesis ch 7 and 8). Because what I took away from Ranger Yost’s talk was that the geologists really have no idea how anything formed, their theories change every decade, and that nature really does reflect God’s glory and prove He exists (see Psalm 19).

Okay, no more soap box from Kelli…Here are some pictures!!








This picture and the one right after it are pictures of dikes. Basically, I think it's the thin protrusions that were formed when magma seeped up through a crack, and then when everything else eroded around it, the formations were left standing.














After our tour, we drove around to different overlooks and vistas and had fun taking pictures. (Erin Valerius, this was for you - we tried to make an "EV" with our shadows in your honor.)



(The lengths we'll go to to get a great picture!)
Then we drove down to the Santa Elena Canyon and hiked along the Rio Grande. It was magnificent! I was blown away by how big the canyon walls were. I didn’t get to go to the bottom of the Grand Canyon when I visited as a kid, but I bet it is a lot like Santa Elena Canyon. UNLIKE the Grand Canyon, we didn’t have to deal with a thousand people all clamoring to see the same vista. During the Ranger talk that we attended on Tuesday night, Ranger Mary Kay even mentioned that Big Bend National Park is one of the least visited National Parks (one of Texas’ best kept secrets in my opinion).


That's Paul down there next to the river.


This is looking back at the mountains from the Rio Grande at Santa Elena Canyon.
After spending about 2 hours hiking around Santa Elena Canyon, we drove some more to different sites. But we hadn't packed a lunch, and by 4pm, some of us were starting to show the effects of low blood sugar. So we went back to camp for some supper!!
Here's the "creative" picture at Mule Ears that I mentioned in my previous post. Paul's such a funny guy, isn't he?


The Window from the NE again, but with the sun higher in the sky so you can see the details better.

2 comments:

Anonymous said...

You guys are awesome. I am honored by your efforts, only wish I could have been there. Awesome pics by the way. You have an eye for this stuff. Love you and miss you! E

Heather said...

I don't remember anything about the time period stuff - what they were named, what happened in them, etc. But I do remember how the formations were formed. The first with the slanted layers: The layers are sediment that were laid down over time (as part of the ocean bed I think). Later on after the ocean dried up, the bed was thrust up on one side.

We asked the ranger about the chimney looking formation. She didn't know for sure what made it, but thought it was probably a vent in the ocean floor. Over time, minerals built up around the vent.