Jump to content

Stratigraphy of the Late Cretaceous North America


Troodon

Recommended Posts

Placement of terrestrial formations in the late cretaceous of North America as been constantly evolving and in October 2016 Denver Fowler a Paleontologist at the Museum of the Rockies published a very extensive paper on the subject and updated most units.   This is very important when it comes to understanding dinosaur evolution and aids in describing species. This paper is in the process of going through peer review so is subject to change.

 

Fowler DW. (2016) A new correlation of the Cretaceous formations of the Western Interior of the United States, I: Santonian-Maastrichtian formations and dinosaur biostratigraphy. PeerJ Preprints 4:e2554v1https://doi.org/10.7287/peerj.preprints.2554v1

 

The paper is pretty technical but all of the data is found in this excel file (supplemental information) which is a massive high-resolution stratigraphic chart for all of the formations from the late cretaceous of North America.  It's nice to see it all laid out and a great reference source.

 

https://doi.org/10.7287/peerj.preprints.2554v1/supp-1

 

To make it easy I've broken the chart apart so you can easily see most important dinosaur formations

 

Texas 

The biggest change came with our understanding the Aguja and Javelina Formations of Texas part of the Tornillo group.   The study indicated that the Aguja Formation deposits are only Campanian in age and that the Javelina Formation does not extend into the end of the Cretaceous.  Very important when trying to describe species in those formations.   Sellers have been comparing the Aguja to the Judith River in Montana well there is a correlation but its deposits are much younger that JR.

 

58f76fdb2eefe_TornilloGroup.jpg.d7c21e87beb0b42683bc1a222328d863.jpg

 

Eastern Montana, N. Dakota, S. Dakota and Wyoming

What I found interesting is that the Hell Creek is much older in Montana than in the adjacent states.   The other interesting observation that can been easily be seen on these charts is that the how short a time frame the deposits of the Hell Creek/Lance formation are compared to the other major dinosaur formations.

 

HellCreek.thumb.jpg.e744d94d99380bc788a3df1aa9b72195.jpg

 

Central Montana

Two Medicine and Judith River Formations are the two key formations in this locality

 

TwoMed.jpg.1bfc86ca1de1fdb0f9b125d0e3c6b8ab.jpg

 

Utah and New Mexico

Utah depicted on the left and NM on the right

 

utahnm.jpg.fd773f2ecee7b7956d1a6b6db30a7990.jpg

 

Head North to Canada

 

Alberta and Saskatchewan

 

NWCanada.jpg.1f3921bfbb4472a9fcad8716af56d168.jpg

 

Alberta2.jpg.08adbfa598771d5a3eb846c5c2d52009.jpg

 

58f76fd23b0de_HorseshoeCanyonFm.jpg.dec5bcb0ede3ab49b85ebbf3972383ac.jpg

 

 

Link to comment
Share on other sites

I knew there would be nothing for the West Coast, though it is part of 'Western North America'.....

Looks like a pretty good resource anyway.

Link to comment
Share on other sites

Thanks for taking the effort to post this. I took some screen shots.  Good to have some current info.

 

Just a note.  These are based on info available to build stratigraphic models.  It needs to be remembered that not all areas are studied to the same extent.  For example the 'Wapiti' in Alberta is a bit if a holding tank as it has a lot of variability.  Also definitions of  'groups, formations, members' get a bit murky and are often based on precedence in the literature.  

Link to comment
Share on other sites

1 hour ago, Wrangellian said:

I knew there would be nothing for the West Coast, though it is part of 'Western North America'.....

Looks like a pretty good resource anyway.

 

These are non marine terrestrial formations. There's lots of Cretaceous stratigraphy in western N. America but its mostly marine.

 

On a quirkier note, when we are talking geology at the GSC we dont consider the west coast as North America. Of couse it is geographically  but geologically its 'another beast'.

Link to comment
Share on other sites

6 hours ago, Canadawest said:

 

These are non marine terrestrial formations. There's lots of Cretaceous stratigraphy in western N. America but its mostly marine.

 

On a quirkier note, when we are talking geology at the GSC we dont consider the west coast as North America. Of couse it is geographically  but geologically its 'another beast'.

I knew you would state the 2nd line, but about the first line, I'm confused: Which are non-marine?

 

Link to comment
Share on other sites

12 hours ago, Wrangellian said:

I knew there would be nothing for the West Coast, though it is part of 'Western North America'.....

Looks like a pretty good resource anyway.

 

It covers Alaska and NW alberta

Are there late cretaceous terrestrial deposits in the the west coast that were omitted from this study?

Link to comment
Share on other sites

Thanks for sharing this Frank!

Looking forward to meeting my fellow Singaporean collectors! Do PM me if you are a Singaporean, or an overseas fossil-collector coming here for a holiday!

Link to comment
Share on other sites

8 hours ago, Troodon said:

 

It covers Alaska and NW alberta

Are there late cretaceous terrestrial deposits in the the west coast that were omitted from this study?

No, it was me that was omitting to read the very first line of the post which said "Placement of terrestrial formations..." :blush:

...although there are terrestrial components to our Nanaimo Group, with plant and other terrestrial material here and there. It would be interesting to see how they correlate with the Interior Seaway formations.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...