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Sunday, December 17, 2017

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Liquid Nitrogen, Blow Torches and Plasma
Shumla Archaeological Center

May, 2017

Note from the Director
 
How old is the rock art of the Lower Pecos Canyonlands? It's a question anyone who has viewed or studied the art has asked. 
 
For a long time it was impossible to apply radiocarbon dating techniques to rock art. That is, until Dr. Marvin Rowe and Dr. Jon Russ at Texas A&M University developed a process that made it possible to prepare tiny samples of paint for radiocarbon dating in 1990. Our own Dr. Karen Steelman joined Dr. Rowe's laboratory in 1999 and has been continuing to develop this pioneering research. 
 
Since that time 33 paint samples from the Lower Pecos have been dated. These dates have shown that the art was produced between 4,200 and 1,200 years ago. We have many more sites to date and may find even older and younger dates. 3,000 years is a really long time for a people to produce the same style of art in the same location. It seems that learning the answer to the antiquity of the rock art only leads to more and more questions. And we wouldn't have it any other way! 
 
I'll share more on the Big Questions the study of this art can answer in our next eNewsletter. Until then, enjoy these incredible images of Shumla's new Plasma Oxidation Laboratory.
 
All the very best,
Jessica
 
Shumla Executive Director
 
What is Plasma Oxidation?
 
Plasma - Plasma is the fourth state of matter (solid, liquid, gas and plasma). Plasma is ionized gas produced by exciting molecules with electricity, heat or other stimulus. You see it everyday in neon lights.
 
Oxidation - Oxidation is a type of chemical reaction. In our case, oxidation refers to the reaction of oxygen with carbon to produce carbon dioxide and water. 
 
Plasma Oxidation - Plasma Oxidation is a technique where we excite oxygen molecules with electricity to make them react with carbon in our paint samples. This allows us to capture the organic carbon, which can be dated through radiocarbon dating. The date tells us how long ago the paint was produced by the original artist. 
We Are 
 For Business!
 
Shumla's plasma oxidation laboratory is operational!
 
Our plasma oxidation lab is one of only two in the world and is devoted to the preparation of ancient paint samples for radiocarbon dating. 
Check out our "plasma ox" instrument and scientists at work!
 
 
Above on the left you can see the custom-designed plasma oxidation instrument. Shumla's Assistant Research Director, Dr. Karen Steelman (pictured right), built it herself, based on over 15 years of research. 
 
This air-tight system is composed of commercially-machined parts including valves, metal fittings, and a glass sample chamber. We use a vacuum pump to remove excess gas and contaminants. Then, specialty gases, such as ultra-high-purity argon and research-grade oxygen (seen in the background on the left), can be delivered to the sample chamber.
 
Pressure gauges such as the ion gauge (above) and thermocouple (below), being read by Shumla intern Marie Desrochers, are critical for monitoring the gases moving inside the instrument's chambers.

 
Karen is training Marie how to operate the instrument. Marie recently graduated with a B.A. degree in Art History and a minor in Chemistry. She is pursuing a career in art conservation.
  
 
The action really happens here - in the glass sample chamber. We run a radio frequency charge to this chamber through copper electrodes. This results in a glow discharge, or plasma, as the gas molecules are excited.  See the bright glow? Our paint sample is inside there.
 
 
The excited gas molecules react with the carbon in the paint sample to make carbon dioxide and water. We trap these reaction products in a glass tube by freezing them with liquid nitrogen. 
This tube is removed from the system by flame-sealing (melting the glass) with a blow torch. Finally, the carbon sample is sent to a national service laboratory for radiocarbon dating. 
 
Then we do it all over again...and again...and again.  
 
We look forward to sharing the dates of our ancient paint samples!
  
It's Official! Comstock has a Historic Cemetery, thanks to the Shumla Scholars!
Comstock's Historic Texas Cemetery
This week, the Shumla Scholars both past and present awarded Alicia Robertson, the cemetery association president, a certificate from the Texas Historical Commission (THC) designating the local Comstock cemetery as a Historic Texas Cemetery. This was the result of the Shumla Scholars efforts to fully document the cemetery using Shumla's methods and preparing a nomination document that was considered and accepted by the THC. Megan Tackett from the Del Rio News Herald was there to witness the occasion and interviewed the students.
 
Well done, Shumla Scholars! This designation will help protect Comstock's deep and rich history for many, many years to come!
Spotlight on the Dangers of Texting While Driving
 
Last month you met Shumla's newest Board Member, Judge Ken Law. Shortly after the eNews was published, Ken was in a horrible car accident. The other driver hit Ken going over 65 miles per hour and didn't even tap the brakes. Why? Because he was on his phone. 

DUI, or driving under the influence, used to only mean under the influence of a substance like alcohol or drugs. Today, however, driving under the influence of our phones is quickly becoming an equally dangerous proposition. 

Ken was lucky to survive the accident with a broken neck, hip and compound fracture of his femur. He was care-flighted to the hospital where he was rushed into emergency surgery. He will be in the hospital and in physical therapy for many months. 

Ken is incredibly strong in body and character and he will be okay. His eternal optimism and easy laughter, along with the support of his family and friends will get him through. I know you'll join me in wishing him a speedy recovery.

Please join us, Shumla's Staff and Board, in a promise to ourselves, our loved ones and to all those unknown to us that we pass on the road, that we will keep our phones out of our hands and our eyes on the road while operating a vehicle. Thank you!
Photo credit: Jerod Roberts
Marfa Public Radio Spot

Shumla Director, Jessica Lee, was recently interviewed for a piece on Marfa Public Radio called NATURE NOTES: In the West Texas Canyonlands, Shumla Center Works to Preserve An Ancient Painted "Library."
 
She talks about her first encounter with the art of the Lower Pecos and the passion that drives her and the whole Shumla team to preserve this Texas treasure. Click here to listen!
Photo credit: Jack Johnson
Make Us Smile!
 
Want to do some good with every Amazon purchase you make? Designate Shumla as your charity on Amazon Smile. We'll receive .5% of every purchase you make at no additional cost to you. 
 
Want to send Shumla a present? Check out our Amazon Wish List!

Thank you!
 
Shumla Archaeological Research & Education Center 
P.O. Box 627, Comstock, TX 78837 USA
enews@shumla.org    432-292-4848    www.shumla.org 
 
Shumla eNews is a free eNewsletter published by Shumla. 
Copyright © 2016 by Shumla. All Rights Reserved.
Questions and comments can be sent to: jlee@shumla.org


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