Why Does The Western Interior Seaway No Longer Exist?
- Joe Thomas
The Western Interior Seaway’s genesis – The old Farallon and Kula tectonic plates were subducting beneath the North American Plate during the Cretaceous epoch. This resulted in the deformation of the ground above, forming a massive back-arc basin. Throughout a succession of sea-level rises (or incursions) in the Cretaceous, the basin began to fill with ocean water.
Thus, the Western Interior Seaway was created. In conjunction with the aforementioned plates’ subduction, they suffered partial melting. Multiple strata of ash layers (or bentonites) are preserved today as evidence of volcanic activity caused by the upwelling of ice melt at the edge of the sea. These datable ash layers can be utilized for stratigraphic correlation (or matching rocks of the same age) across the WIS.
Reconstruction of tectonic plate interactions at the period of the Western Interior Seaway in western North America. Further tectonic activity resulted in several sea-level variations in the WIS. At the end of the Cretaceous, the seaway ceased to exist as a result of regional uplift and mountain formation on the western side of North America.
What happened to the Western Interior Seaway?
Fauna – The Western Interior Seaway was a shallow sea, teeming with numerous marine life. Interior Seaway dwellers featured predatory marine like as, and that reached up to 18 metres (59 ft) long. Other marine species includes such as,, and the gigantic -eating (believed to be 10 metres (33 ft) long); and advanced bony fish like,, and the huge 5-metre (16 ft) long, bigger than any current,
Other marine life includes such as,, squid-like, and included that exuded the chalky platelets that gave the its name, and, The Western Interior Seaway was home to early, such the flightless that had robust legs for swimming through water and small wings used for marine steering rather than flight; and the -like, an early bird with a toothy beak.
Ichthyornis shared the sky with big such as and, Pteranodon fossils are exceedingly widespread; it was certainly a prominent player in the surface environment, yet it was found in just the southern sections of the Seaway. (oyster-like bivalve molluscs) were well-adapted to survive in the oxygen-poor bottom muck of the seaway.
These left numerous fossils in the,,,, and formations. There is significant variation in the shells and the numerous diverse species have been dated and may be used to identify certain layers in those rock formations of the seaway. Many species can readily fit in the palm of the hand, while some like Inoceramus (Haploscapha) grandis might measure well over a meter in diameter.
Entire schools of fish occasionally sought safety beneath the shell of the enormous, The shells of the genus are noteworthy for being formed of prismatic calcitic crystals that developed perpendicular to the surface, and fossils frequently preserve a pearly shine.
- Artist’s depiction of a and two circling a dead in the Western Interior Seaway
- platyurus in the in Woodland Park, Colorado
- , an ancient bivalve from the Cretaceous of South Dakota.
This suggests that the creatures perished on land, drifted out to sea, and then sunk. At the conclusion of the Mesozoic Era, dinosaurs, mosasaurs, and many other animals, especially huge ones, perished in a mass extinction. After the final Cretaceous sea withdrew, numerous mammal species grew much larger and expanded over Kansas throughout the succeeding Cenozoic Epoch.
Was El Paso a sea in the past?
The seashells of the Franklin Mountains tell tales that are nearly as old as time By: Karla Draksler Date of publication: March 15, 2021, 11:30 AM MDT 15 March 2021, 11:30 A.M. MDT Texas’ EL PASO (KTSM) – El Paso’s history dates back millions of years to when the desert was at the bottom of the ocean, leaving behind carbonized remnants of aquatic life that may still be found today.
Several hundred million years ago, El Paso was entirely submerged. At various times, we were both farther out at sea and closer to the beach “Amanda Labrado, a doctoral student in Geology Studies in the University of Texas at El Paso, stated as much. Labrado proceeded to narrate a tale nearly as old as time, transporting us back around 500 million years.
Fossils of once-aquatic plants and animals are dispersed around El Paso, particularly in the Franklin Mountains. “There are several varieties of fossils, shells, corals, and brachiopods can be found. Trilobites from the El Paso group are quite interesting and can be found all around Franklins “There are even fossils of sponges and crinoid stems that resemble tubes, remarked Labrado.
- When hiking through the Franklin Mountains or walking through parks in El Paso, Labrado recommends searching for fossils, but cautions against damaging the local geology.
- Labrado added, “We don’t want to harm any of the rocks because the more people remove items from these locations, the less we will be able to see in the future, so we must attempt to conserve as much as possible.” She stated that some fossils may be hidden deeper in the earth and attached to a rock, while others may be in plain view.
She permitted its retention if it could be accessed without harming the earth. Some of these fossils gathered throughout the years may be found in the UTEP Centennial Museum, where they are studied by Geology students. Labrado stated that the El Paso Geological Society organizes treks to anybody interested in exploring the history of El Paso grounds.
Western Interior Seaway during the middle Cretaceous, approximately one hundred million years ago The Western Interior Seaway, also known as the Cretaceous Seaway, the Niobraran Sea, and the North American Inland Sea, was a massive inland sea that divided the North American continent in two throughout the majority of the early and middle Cretaceous Period.
The Seaway was formed when the North American and Pacific tectonic plates clashed, forcing the Rocky Mountains to rise. Numerous fossil sites in North America exist because to the Western Interior Seaway. It was a shallow sea teeming with a variety of aquatic life, including predatory marine reptiles such as 18-meter-long mosasaurs, ichthyosaurs, and plesiosaurs.
There were several sharks, such as Squalicorax, and advanced bone fish, such as Pachyrhizodus, Enchodus, and the enormous 18-foot-long Xiphactinus, which was larger than any extant bony fish, as well as another monster. Other marine organisms included invertebrates such as mollusks, ammonites, squid-like belemnites, and plankton such as coccolithophores, foraminiferans, and radiolarians, which excreted the chalky platelets that gave the Cretaceous its name.
In most parts, the depth of the water was likely less than 200 meters (600 feet), and its bottom was relatively flat, mushy, and composed of mud. The so-called Kansas Chalk is among the most renowned fossil locations (Niobrara chalk formation). In what is now Kansas, sediments were deposited at a rapid rate, resulting in the formation of approximately one inch of compacted chalk every 700 years.
Here, some of the world’s greatest fossils have been unearthed, including crinoid and fish fossils. Early bird fossils originated in the Western Interior Seaway, including those of the flightless Hesperornis, which had thick legs for swimming and short wing-like appendages used for marine steering rather than flight, and the toothed Ichthyornis, which resembled a tern.
Was the Midwest underwater?
This assemblage of marine fossils was discovered in Montana, which was formerly covered by a vast body of water. Wilson44691 – Commons Wikimedia Approximately 100 million years ago, the majority of what is now North America was submerged. The expanse of water that scientists refer to as the Western Interior Seaway extended over the entire Midwest.
However, its secrets have been stored in innumerable fossils, of which over 100,000 are now being scanned. Eight universities are engaged in a massive effort to digitize specimens from the long-lost seaway. With the support of a $2.1 million grant from the National Science Foundation, they will move fossils out of museum drawers and into the public domain by creating a massive digital database with free pictures, 3D models, scans, and classroom content.
The undertaking is ambitious: According to the NSF award, around 164,000 samples must be digitized. It is a corpus of work that will make it simpler than ever to examine a time of remarkable evolution that created our current world. The enormous sea was teeming with dinosaurs, birds, and mollusks, all of which left their remains behind as the water receded.
- Not only did the seaway leave behind fossils, but also other traces.
- Chalk deposits composed of crushed shells are still visible in Kansas, as are rocks and sediments throughout the Midwest.
- Scientists believe that the vanished body of water might give insight into how species dispersed and finally became extinct during the “marine highway’s” heyday, as well as how the warm temperature of the Late Cretaceous may be related to the current global warming trend.
To disclose their secrets, however, these fossils must be accessible; to become accessible, they must be meticulously scanned and catalogued. In a news release, the Yale Peabody Museum of Natural History states that it has digitized over 41,000 specimens in its first year, the majority of which are sea-related bone and shell pieces.