Any local geologists on SA-CD? (San Antonio, Austin: home, live, club)

[wCat]

Anyone here a geologist (amateur or professional) that knows about SA geological history. Total dummy here, other than I know most of Texas falls in the Cretaceous period. We went on and outing yesterday and came home with a zillion questions.

[majormadmax]

wCat

Might try these folks...

UTSA Department of Geological Sciences

I have an undergrad degree in physical geography, but that's been decades ago when I lived in Florida, so my knowledge of local specifics is very limited! However, I can tell a sink hole from a landslide!

Oh, and if you are interested in local geology, I highly recommend the tour at Canyon Lake Gorge; it is a very fascinating place!

Cheers! M2

[huckster]

Yea, If you Go the website -edwards aquifer.net and then click the Hydrogeology tab -the entire story of Texas geology is there in detail. It is a great site with information also on springflow rates ,caves, aquifer levels, water resource history here in S.A. and the surrounding area. Just more stuff than I can describe in a short reply here.
It is GREAT website and I have read every corner of it more than on
one occasion. Many things have happened on this location over millions of years. I guess the Texas coastline was reversed- with the shore line to
the north and away from S.A. and the gulf was a mountain range.
Fascinating stuff, or so I thought.

Originally Posted by wCat

Anyone here a geologist (amateur or professional) that knows about SA geological history. Total dummy here, other than I know most of Texas falls in the Cretaceous period. We went on and outing yesterday and came home with a zillion questions.

[doss1]

Sounds like fun!

Have you guys been to Enchanted Rock yet?

[Smilenknight]

A geologist was one of the 3 things I wanted to be when I was a child, the other 2 were pilot and police officer. I was a MP in the army, now I am in the Air Force (medical) all I need is some rocks to study.

[wCat]

Originally Posted by TexasNick

Sounds like fun!

Have you guys been to Enchanted Rock yet?

Yes, Nick...it's awesome. I wasn't sure what to expect when we saw it. Once you're on it, it's hard to believe the expanse of it.

Thanks all...for the other info. I wish we had time to study it more and go on more explorations. Texas is full of a lot of fun things to explore. I know the basics about Texas in general, but we found a few things this weekend that were really neat.

BTW...MMM...I have been dying to go to the gorge for sometime. Unfortunately an injury prevented the four hour tour.....plus I understand the wait to go is weeks if not a few months long. This would be the time of year to go. The weather was perfect this weekend for exploring, other than the wind.

The only way to describe it was an external fossil mold of a plant. It almost looked like a delicate branch coral design etched into this limestone and bedrock. It's hard to explain because we didn't break it open to find it.

Imagine walking on a flat rock bed along side several step up layers that look like a steep street curb. Apparently maybe in a heavy rain in recent years, a large rectangular chunk of the "curb" snapped off and just fell over on it's side. The very bottom layer was limestone that was pitted and looked like swiss cheese....like the limestone in the aquifer. The middle layer was a light sandy color but hard and sparkled like it was crystalised. The top layer was white/gray solid rock. Right where it split, was this beautiful pattern of this plant.

Here's a couple of pictures ...a little hard to see because it was getting late in the afternoon and the light was not great. Hope it shows up...... I'm ready to go back!

I just want to talk to a geologist to see what it is. We were not sure if it was something growing, or if it was upside down and we were looking at the roots.

This first closeup shows the sandy colored layer. It looks really soft like beach sand but it is very hard. We tested a spot to try to chip off a corner and it did not break easily. The little holes are apparently where the branches or roots were.




The pic below shows a view of the chunk of rock that snapped off somehow. There is another little fossil growth off to the right, but not as easy to see.

[gy2020]

Cat, I was a geology major and took courses at SAC and later UT Austin. Math was my downfall. I later took some courses at UTSA long after my Business Degree from UT Austin. San Antonio's southside has seen about 70 shorelines since the Cretaceous, 65,000,000 years ago. That's why all the sand on the southside. The northside of Bexar County (hill country) is Cretaceous, the southside much more recent. There are many dinosaur footprints from Bandera, Blanco and in between. Also around Canyon Lake. Over in Bandera County you can see some Allasaurus prints. The prints near Blanco are sauropods. Most of the prints are in the Glen Rose formation which dates 100,000,000 years. This is the same formation that you see in Glen Rose, Texas, where Dinosaur State Park exists.

Back in this time, the ocean ran from the Gulf to Canada slicing the US in half. During the Cretaceous we were in the ocean. West Texas up to Canada along the Rocky Mountain spine is where you can find dinosaur bones. All we seem to find are footprints. When you do find bones in this are they tend to be of marine variey. Back about 1988 a young boy, and his father, were walking along Slaughter Creek in South Austin and the boy spotted some bones. The father contacted UT Paleo dept and they uncovered a Marine Reptile, similar to Lock Ness monster (a plesiosaur, that is long neck, long tail and four flippers. It appeared it ran into an underwater rock formation that broke its neck.

If you do see large bones, that many interpret as dinosaurs in this region, they are usually mammoths that ranged the area up to about 10,000 years ago.

Back in 1987, a friend and I started the Geology Club of San Antonio. I no longer attend, but I was there untill 1999 when I moved to St. Louis. The current president is Larry Tillick and his email is ltillick@sbcglobal.net. The club meets monthly and has a field trip each month. I'm sure they would like to hear from you and anyone else interested in this hobby.
gy2020

[gy2020]

Cat, from the two pictures above. Its possible those are marine invertebrates (tube worms) that have made trails in the mud that were later fossilized. They could also be marine plants. Someone needs to see them or the actual photo. It could also just be erosion. Nature has a funny since of humor. I have seen what I thought was a fossilized snake, but my prof never bought it. If you see dinosaur footprints, they don't exist unless you have more than one. Here is a sauropod trailway near Blanco, Texas.

[doss1]

Read something the other day that blew my mind:

To get an idea of how long the dinosaur era spanned, you can place one T-Rex in Los Angeles in single file all the way to Brooklyn, while compared to human existence, humans only can span the length of Madison Square Garden.

Plenty of fossil fuels.

[brenty13]

I have a geologist friend who works at Southwest Research Institute. I'll see if I can get a hold of him to find out more info for you.