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November 6, 2016 Weekly Geology Guess: The K-T Boundary.

November 6, 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
Cretaceous – Tertiary Extinction
A bad eon to get out of bed

“The Cretaceous–Paleogene (K–Pg) extinction event,[a] also known as the Cretaceous–Tertiary (K–T) extinction,[b] was a mass extinction of some three-quarters of the plant and animal species on Earth that occurred over a geologically short period of time[2][3][4] approximately 66 million years ago.  ”    Wikipedia

There is a tremendous amount of material written about this extinction event.  The popular TV presentation of the event is a 6-8-mile wide asteroid striking the Yucatan Peninsula.  This event ended the Reign of the Dinosaurs and allowed the mammals to become the next ruling life form.

Other events may have combined to cause this extinction event, they include

–    Chicxulub Impact

–    Deccan Traps flood basalts (volcanic)(West-Central India)

–    Multiple Impact Event

–   Maastrichtian sea-level regression

–    Multiple Causes

The Alabama Cretaceous – Tertiary Boundary Impact Hypothesis from “Lost Worlds in Alabama Rocks” by Jim Lacefield

–    The impact was quite close to Alabama.

–    “The impact created huge tsunamis, or seismic sea waves, hundreds of feet high along the Gulf of Mexico coastline that devastate the coastal plain for many miles inland.”

–    “Storm deposits of unprecedented proportions dating to the time of this event are found in Texas and other areas.”

>    Note:  Sea level was higher in those times so the coast line was located further inland.

–    “Tiny beads of glassy rock known as tektites that are believed to have been formed from the crustal melt during the impact are spread across the Gulf and Caribbean regions.”

–    “The impact caused severe environmental damage that included global wildfires, an atmosphere so contaminated with dust and soot that sunlight could barely penetrate for many months, strongly acidic rainfall, and a virtual collapse of all ecosystems on Earth at the time.”

>    K-T boundary sites found in Alabama:

        +    Moscow Landing on the Tombigbee River in Sumter County.

        +    Shell Creek in Wilcox County.

        +    Mussel Creek in Butler County.

Geological Survey of Alabama, Reprint Series 112.  The Cretaceous-Tertiary Boundary at Moscow Landing, West Central Alabama.

K – T Boundary Images
Cretaceous-Tertiary Videos
1.    The K-T Extinction [3}.  7 Worst Days on the Planet Earth.

2.    Walter Alverez and the K-T Boundary Story.  Dr. Alverez and his father co-authored the original hypothetical article on the asteroid impact (now the Chicxulub Impact Crater).
>    Very good and humorous video.  R

Attached Images:

1.    Extinction Graph:     The blue graph shows the apparent percentage (not the absolute number) of marine animal genera becoming extinct during any given time interval. It does not represent all marine species, just those that are readily fossilized. The labels of the “Big Five” extinction events are clickable hyperlinks; see Extinction event for more details. (source and image info)


4.    A Wyoming rock with an intermediate claystone layer that contains 1000 times more iridium than the upper and lower layers. Picture taken at the San Diego Natural History Museum

>    As some of you will notice, as we go up the geologic column the more complex and numerous life becomes.

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 Cenozoic, Paleocene (Tertiary) Period.


Enjoy the adventure!













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