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October 23, 2016 Weekly Geology Guess of the Cretaceous Period

October 22, 2016
Greetings from the Bluff Park Back Porch, way up yonder on Shades Mountain (1,109′) in Alabama:

My discussion on Alabama Geology will continue with the Geologic Time Scale or the Geologic Column and the critters that abide within each pigeon holes.

As with most sciences, especially natural sciences, we love to pigeon hole our data.  Most of the pigeon holes have scientific merit and accuracy.  With the Geologic Time Scale we start with the oldest layers and work upward to the youngest layers.

For some of you this will be new, novel, and maybe heretical.

Expedition Earth: Geological time scale
zoic  Era

Mesezoic Era

“The Mesozoic Era (pronunciation: /ˌmɛsəˈzɪk, ˌm, s/ or /ˌmɛzəˈzɪk, ˌm, s/[1][2]) is an interval of geological time from about 252 to 66 million years ago. It is also called the Age of Reptiles or the Age of Conifers.[3]

The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth’s history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction which is known for having killed off non-avian dinosaurs, as well as other plant and animal species. The Mesozoic was a time of significant tectonic, climate and evolutionary activity.”  Wikipedia

Cretaceous Period

“The Cretaceous (pronunciation: /krˈtʃəs/, krə-TAY-shəs) is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago (Mya) to the beginning of the Paleogene Period 66 Mya. It is the last period of the Mesozoic Era. The Cretaceous Period is usually abbreviated K, for its German translation Kreide (chalk).

The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists, while dinosaurs continued to dominate on land. During this time, new groups of mammals and birds, as well as flowering plants, appeared. The Cretaceous ended with a large mass extinction, the Cretaceous–Paleogene extinction event, in which many groups, including non-avian dinosaurs, pterosaurs and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt K–Pg boundary, a geologic signature associated with the mass extinction which lies between the Mesozoic and Cenozoic eras.”

The write up in Wikipedia includes a lot of interesting details.

Encyclopedia Britannica



Alabama Cretaceoous Period Paleontology and Geology

“Rocks from the early part of the Cretaceous Period are all deeply buried in Alabama, but the last half of the Cretaceous is well preserved at the surface. These rocks contain both freshwater and nearshore sediments, indicating that the shoreline of the Gulf of Mexico lay far inland from its present position. This sandy shoreline ran from near Auburn in the east to just north of Montgomery and Tuscaloosa, then curved northward to just west of the Muscle Shoals area.

Fossil leaves from these sedimentary layers suggest that near-tropical forests covered the part of the state not inundated by the sea. Offshore lay a rich, warm ocean filled with marine life that left behind many fossils of clams, snails, ammonites, nautiloids, and even some complete skeletons of marine vertebrates such as turtles, fish, and mosasaurs. Fossils are so abundant in these layers that Alabama is recognized as one of the best locations in the world for collecting a variety of Cretaceous marine fossils”

Cretaceous Images


Cretaceous Video

(See the dinosaurs dancing to Star Wars music???)

>    I decided to go with some simpler pictures rather that all the cut and posting that goes with the individual photos.  Thanks, R

?????    Let me know which method you prefer, videos or slides.  R

>    As some of you will notice, as we go up the geologic column the more complex and numerous life becomes.
>    As with most of my weekly fores into geology, with each topic I could write many papers and dissertations.
Note:  I have intentionally reduced the amount of linked graphics in this email due to the amount of space required and trying to untangle everything the following week has been a mess.
References include:


–    Wikipedia
–    “Lost Worlds of Alabama”, Second Edition, 2013, by Jim Lacefield


Editors Note:  It is the intent of this site to keep this discussion as simple as possible, so as to educate the interested general public and not to discuss with the geology crowd the latest geologic theories and nuances.  Thanks, R
“No copyright infringement intended.
The rights belong to their respective owners”
Copyright Disclaimer: Under Section 107 of the Copyright Act 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use.


Author’s Request:  If you see any pictures that you know the source and photographer, let me know immediately.  Thanks!  R

Images have been searched by TinEye Reverse Image Search.


Next time we will venture into the Paleocene Period.

Enjoy the adventure!
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