An Upside-down Land

No, not Australia, New Zealand, and those places well south of the Equator. I’m thinking about the area where I live. It’s been said that people should have known that Texas was odd because they had to dig for wood and climb for water. Up here, you also have to dig to get to the mountains.

People driving east on I-40 get to see just how dramatic the plateau of the Llano Estacado is. Those coming from the east observe their rapidly dropping gas gauges, and that the semis on I-40 or US-287 seem to be staggering a bit. Then the land flattens out, and people don’t realize that they’ve come up two thousand feet or so, until they start panting and wheezing. Welcome to the High Plains and the enormous plateau lurking between the Canadian River and the Edwards Plateau.

Underneath the mostly-flat surface lies a mountain range. It is very, very old, as in around 300,000,000 years old, and lies along a fault system that ties it into the Wichita Mts of Oklahoma.* No one had a clue that such a thing might exist until the 1920s and 1930s, when people drilling for oil kept hitting granite. They also observed that most of the oil and gas followed a northwest-southeast line to the east of the granite. That didn’t fit with what people knew about the Anadarko Basin. As companies published their seismograph studies and well logs, people realized that a mountain range lay hidden under the surface. If you dig, you get to the mountains.

Blame other mountains for the lack of downhill skiing in the Texas Panhandle. All the sediment that washed off of the Rocky Mountains as they rose had to go somewhere. Back then, rivers as large as the Amazon carried millions of tons (or tonnes) of sand and gravel onto the flat land east of the volcanoes and rising fault-block peaks. The ancient mountains also sank as this part of North America disappeared under the Cretaceous Interior Seaway, 145-66 million years ago, more or less. They formed an excellent trap for oil and gas, and helium.

People found the gas first, much to their disgust. They wanted water. Instead, “bad air” blew the drill bit and casing out of the hole. To make things worse, natural gas was considered an unwanted and useless hazard when people wanted oil. Not until the 1930s did the “dirty” local natural gas become a source of carbon black and fuel.

So you have to climb a windmill in order to get water, and dig for mesquite roots to get wood. And excavate a thousand feet of soil and gravel to reach mountains. No wonder this part of the world is a little eccentric!

*You can see these around Altus, OK, in the southwestern part of the state.

For more about the geology, try THIS article, originally from the Shale Shaker Digest. It’s pretty technical, but not bad. Skim to around page 20 and later for the western part of the mountain and fault system, or red the entire thing for a very good picture of the system and how it might have formed.


8 thoughts on “An Upside-down Land

  1. Three hundred million years … that’s the end of the Carboniferous. Maybe connected with the end-Carboniferous extinction?

    Go back a bit further, to about 335 million years, and you get to the time when the supercontintent Pangaea was forming.

    Historical-geology puzzles are fun.

  2. Now I wonder if the continental shelf off the Atlantic coast hides a similar low range. The young Appalachians were 6-7 miles high in many places, and all the sediment washed down both sides. Time to do some research.

    • I don’t think so. The Atlantic Ocean only dates back to the early Jurassic, roundabouts 200 million years ago. The ancestral Appalachians are much, much older – like, “before Pangaea” old. If they buried any older mountains to their east, those mountains would today be somewhere under western Europe.

      • That’s right, should have remembered the plate broke and separated. Shelf is probably the remains of collision, buried under gravel and sedimentary rock.

  3. The continental shelf is NOT like Texas, no stray mountain ranges under it, just a gradual slope for about 600 miles… And a ‘note’ on the gas, quite a bit of it IS poisonous… Just for an added fillup, if you will.

  4. No buried mountains, just a sunken continent – 94% of the continent of Zealandia that formed when Gondwanaland split 83-79 mYA is under water. What you see on the map today as New Zealand is just the backbone of that forgotten land. The historic of plate tectonics is a fascinating study.

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