Recent searches
Search options
@dinogami@sauropods.winSandstone-infilled paleochannel in the Lower Jurassic Kayenta Formation in St. George, Utah. A standard stop for all of our introductory-level geology course field trips, and a great example of a disconformity! #geology #geoscience #jurassic #kayenta #utah #stgeorge #redrock #sedimentology
@dinogami Awesome outcrop!!
@DrRocktagon Thank you! It really is! The horizon the paleochannel is in has two others just lateral to the one shown in the same outcrop, but I've been as yet unable to get a good photo of the whole thing showing all of them!
@dinogami sounds like a good job for a drone. It is great to be able to get that eye in the sky and still have detailed photos of entire outcrops
@DrRocktagon Agreed--I've had the same thought, but no opportunity as yet to do it! Our department does have a drone, and I REALLY need to learn to use it! Sooo many things around here need it for the best geology shots!
@dinogami Ohhh, how utterly lovely! Wish I could have done some of my geology studies in the US...
@dinogami @vickyveritas For the ignorant normal person, explain what I’m looking at and how it was formed, please
@tombarkas @dinogami I will. I have a busy morning today, but I’ll get back to this later.
@tombarkas @dinogami Sorry, got this mixed up with another post. LOL! Great stuff, Jerry!
@vickyveritas @dinogami Is that an example of a disconformity or a unconcomformity?
@tombarkas @vickyveritas Well, a disconformity is a type of unconformity (along with angular unconformities, nonconformities, and paraconformities). So it is both! 
@dinogami @vickyveritas Do you know the geology stuff (I’m using technical terms here) around Inchnadamph in NW Scotland? The unconformity stuff if I’m correct. I’d spent years looking at the map in this area and telling people hills just didn’t do this, then I found out why!
@tombarkas @vickyveritas If I'm not mistaken, that's the general vicinity where the Torridonian units nonconformably overlie the Lewisian Gneiss...?
@dinogami @vickyveritas Speaking as an idiot non-specialist, you could be right! Does this make any sense?
@tombarkas @vickyveritas Ah, it does! So the Eriboll Quartzite sits in some places atop the Torridonian Sandstone (this contact would be a disconformity), and in other places atop the Lewisian Gneiss (this contact would be a nonconformity). This implies that, when the Eriboll was being deposited, the surface on which deposition was occurring had the gneiss exposed in some places and the Torridonian Sandstone exposed in others.
@tombarkas @vickyveritas Happy to! So, the layer in the middle of the outcrop with the flat top but down-bulging bottom is the paleochannel. It's basically a cross section through what used to be a stream channel ~195 million years ago: at that time, what is now that flat top was ground level, and a stream flowed out of (or into) what is now the outcrop face. At some point, the stream abandoned this channel and it got filled in with sand.
@dinogami @vickyveritas Thanks! That’s very interesting