I stumbled on this construction site while walking my dog the other day. There's a vertical cut showing about 4' of strata.
Here's another cross section from a few feet away showing a narrower, more distinctly red band:
I'm most interested in the redish/brownish band in the middle. Is this from the shallow sea, or are these river deposits? It's a redish sandy clay with smoothed rounded pebbles, these must have been formed either by beaches/shallow seas(millions of years ago), or by river runoff during glacial melting(10k to 20k years ago)So my question is, are these pebbles just 10s of thousand of years old, river pebbles from ice-age runoff? Or are these ancient beaches with sand and pebbles from 100s of thousands or millions of years ago?
Most pebbles are 0.5 inches to 2 inches. See below:
Anyway it's pretty cool to think DFW used to be on top of a vast mountain range with peaks as high as the contemporary Rockies, and was also a beach and shallow sea at times. I guess I didn't time my property investment properly.
cross posted on DFW board
https://texags.com/forums/37/topics/2867319
- this is half a mile from White Rock Creek in central Dallas county, a Trinity River tributary
- My research has discovered the Trinity was once much larger with a much greater flood plain
Here's another cross section from a few feet away showing a narrower, more distinctly red band:
- The top layer is 1-2 feet stiff clay(I'm pretty sure).
- At 3-4 foot depth, whitish band at the bottom, is "slightly weathered chalk" from the Austin chalk formation(I think), which would be 65 million years old. Formed from coral reefs when Texas was under the ancient North American Seaway.
I'm most interested in the redish/brownish band in the middle. Is this from the shallow sea, or are these river deposits? It's a redish sandy clay with smoothed rounded pebbles, these must have been formed either by beaches/shallow seas(millions of years ago), or by river runoff during glacial melting(10k to 20k years ago)So my question is, are these pebbles just 10s of thousand of years old, river pebbles from ice-age runoff? Or are these ancient beaches with sand and pebbles from 100s of thousands or millions of years ago?
Most pebbles are 0.5 inches to 2 inches. See below:
Anyway it's pretty cool to think DFW used to be on top of a vast mountain range with peaks as high as the contemporary Rockies, and was also a beach and shallow sea at times. I guess I didn't time my property investment properly.
cross posted on DFW board
https://texags.com/forums/37/topics/2867319