Deep Time

Deep Time

The use of ground penetrating radar is a geophysics and remote sensing technique meant to allow for the detection and mapping of subsurface features. It’s been extraordinary being able to learn how to use this device to find anything from archeological artifacts, changes in bedrock, and other subsurface features.

Our GPR unit’s interface, you can see a few “peaks” near the upper right corner of the screen, evidence of underground features/ changes in the lithology.

I’m finishing my report on the work we’ve accomplished this summer. As I research the past archaeological excavations that coincide near the areas where we have identified subsurface features, I will add potential interpretations of what these features may be based on the data we have collected and these past reports.

Some other data we’ve collected include rainwater runoff from downspouts near where a sinkhole appeared several years ago, close to the foundation of Mission Concepcion. We suspect water flowing from these downspouts could be partly to blame for the topography changes seen in the compound. We have tested the water using a chemical direct reading titration and Ion Chromatography to reveal any metal anions that might be present in the water. I’m happy to be learning a lot of useful skills this summer, skills that I hope serve me well in my future career path!

Snapshot of our titration testing for Total/Calcium hardness of our rainwater runoff samples of the church’s roof.

To finish up, I’d like to touch on the GIS side of things. So far, I’ve created some fairly handy maps to go along with my report. Using the GPS data we have also collected this summer, I also managed to create a digital elevation model and elevation profiles based on this DEM, which appears to fit quite well when compared to a county-wide lidar dataset for the city of San Antonio. Our data is a bit more accurate and will hopefully be used to compare to future studies in order to detect any topography changes like the appearance of sinkholes!

An example of an elevation profile comparison between our GPS data and the county-wide lidar data in units of feet.

It feels like I’ve been here for a long time despite it having been only a couple of months, which I find weird to say as a geologist who has to learn of the timescales of millions of years. I’ll be sad when I must finally leave and end my internship. Nonetheless, I’ll enjoy the time I have left and the deep feelings I have grown here at the park! Thanks for reading! 🙂

Also, enjoy a picture of these really beautiful and really old rocks!

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