Sunday, January 30, 2011

Evolution

I'm fascinated by the process of evolution.

The Texas Hill Country is ribboned with rivers.  Most spring from permeable limestone formations imprisoned by dense rock. The rivers make this land habitable.  And desirable.

Denny and I drink water from the Edwards aquifer, a formation of limestone created and eroded as shallow seas rose and fell, until water could pass through the limestone, trickling, flowing through cracks, fissures, crevices, caverns.  

The Edwards was eventually surrounded in dense layers of rock, until it became a captive limestone vessel.  
Map from the Edwards Aquifer Website. 

One imprisoning layer, the Del Rio Clay, "consists primarily of windblown ash that originated with volcanism on the Pacific coast of Mexico." (1)

I don't think of Pacific coast volcanoes when I go down to the Guadalupe River and dabble my toes in the swift cold water.  But if, somewhere in the stretch  between 248 to 65 million years ago, ancient volcanic ash had not erupted and been carried here, the Texas Hill Country would support little human life.

Today the Hill Country is a land of stark beauty, a good place for contemplation and exploration.  
We came from yesterday, but today is ours.

(1) from Hydrogeology of the Edwards Aquifer

Copyright 2009-2011 Kathleen Scott, for Hill Country Mysteries. Unauthorized reproduction is prohibited.

11 comments:

  1. That is amazing and how great to drink spring water from an aquifer, it would be sweet and fresh and no pollution.
    That little water bird is adorable, is it a duckling?

    xoxoxo ♡

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  2. Out of curiosity, is canoeing a big pastime in your area? Those rivers look quite inviting.

    Cheers.

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  3. We, too, drink from an aquifer here. The best water.
    This was just a gorgeous post.

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  4. Very interesting. And to think - water is the beginning of everything.

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  5. You never realize how lucky you are to have great water to drink until you move to a house that requires all kinds of treatment just to make it palatable.
    Enjoy your fresh tasting water! Such a gift.
    Very interesting post!

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  6. Kathleen,

    For many years now you've shown a keen interest in the natural beauty of the things around you, particularly in the details of those things that many of us often overlook. This is one of the reasons why I find your photographs and descriptions of the natural beauty you blog about so captivating.

    However, in your blog today, I think I sense another important influence in your life. A regional aquifer map and reference to a geological event that occurred over 65 million years ago? Methinks someone is very pleased that her long-separated little sister, an accomplished professional geologist, has returned to Texas. Consciously or not, I think your blog today reflects another sentiment, "Welcome home, Woos!"

    Wilson

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  7. The latest issue of How to Find Great Plants is here and your Texas betony post is featured. Thanks so much for participating, I hope you will again next month. Here’s the issue:

    http://www.appalachianfeet.com/2011/02/01/how-to-find-great-plants-issue-3/

    I love the photo of the little duck and the underground plants. Your aquifer sounds like a delightful place to visit (and it is always nice to see people appreciating where their water comes from).

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  8. I truly enjoy getting to know more about your state through your writings. Such a bounty of nature and beauty.

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  9. Oh! To dip your feet in a body of water without worrying about being yanked under by by a gator or doing the stingray shuffle. Lovely!

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  10. Well put! You always have a wonderful way of making me want to go out and learn new things!

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  11. This is wonderful! Thank you for the reminder about our connection to the past that makes a difference today. And for the geology lesson!

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My readers are all geniuses. Can't wait to see what you have to say.