Word Formation | |
---|---|
Stratigraphic range: Roadian-Wordian ~ | |
Type | Formation |
Sub-units | Appel Ranch, China Tank & Willis Ranch members |
Overlies | Road Canyon Formation |
Lithology | |
Primary | Limestone |
Location | |
Coordinates | 30°24′N103°12′W / 30.4°N 103.2°W |
Approximate paleocoordinates | 1°36′N33°00′W / 1.6°N 33.0°W |
Region | Texas |
Country | United States |
Extent | Glass Mountains |
Type section | |
Named for | Old Word Ranch |
The Word Formation is a geologic formation in Texas. [1] It preserves fossils dating back to the Permian period. It is probably named for the Old Word Ranch in the Glass Mountains of Brewster County. [2]
The Wordian age of the Permian Period is named for the Word Formation. [3]
The formation is subdivided into three members, from young to old:
The limestone formation contains marine gastropods, brachiopods and ammonites. [1]
The Permian is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia.
The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0.5 – 259.1 ± 0.4 Mya. The series saw the rise of the therapsids, a minor extinction event called Olson's Extinction and a significant mass extinction called the end-Capitanian extinction event. The Guadalupian was previously known as the Middle Permian.
In the geologic timescale, the Capitanian is an age or stage of the Permian. It is also the uppermost or latest of three subdivisions of the Guadalupian Epoch or Series. The Capitanian lasted between 264.28 and 259.51 million years ago. It was preceded by the Wordian and followed by the Wuchiapingian.
In the geologic timescale, the Roadian is an age or stage of the Permian. It is the earliest or lower of three subdivisions of the Guadalupian Epoch or Series. The Roadian lasted between 273.01 and 266.9 million years ago (Ma). It was preceded by the Kungurian and followed by the Wordian.
In the geologic timescale, the Wordian is an age or stage of the Permian. It is the middle of three subdivisions of the Guadalupian Epoch or Series. The Wordian lasted between 266.9 and 264.28 million years ago (Ma). It was preceded by the Roadian and followed by the Capitanian.
The Kaibab Limestone is a resistant cliff-forming, Permian geologic formation that crops out across the U.S. states of northern Arizona, southern Utah, east central Nevada and southeast California. It is also known as the Kaibab Formation in Arizona, Nevada, and Utah. The Kaibab Limestone forms the rim of the Grand Canyon. In the Big Maria Mountains, California, the Kaibab Limestone is highly metamorphosed and known as the Kaibab Marble.
Hercosestria is an extinct genus of brachiopods from the Lower and Middle Permian. They were important reef-forming organisms because of their conical shapes, attaching spines, and gregarious habits. It is related to Richthofenia. Species of the genus have been found in Texas and Guatemala.
Paleontology in Oklahoma refers to paleontological research occurring within or conducted by people from the U.S. state of Oklahoma. Oklahoma has a rich fossil record spanning all three eras of the Phanerozoic Eon. Oklahoma is the best source of Pennsylvanian fossils in the United States due to having an exceptionally complete geologic record of the epoch. From the Cambrian to the Devonian, all of Oklahoma was covered by a sea that would come to be home to creatures like brachiopods, bryozoans, graptolites and trilobites. During the Carboniferous, an expanse of coastal deltaic swamps formed in areas of the state where early tetrapods would leave behind footprints that would later fossilize. The sea withdrew altogether during the Permian period. Oklahoma was home a variety of insects as well as early amphibians and reptiles. Oklahoma stayed dry for most of the Mesozoic. During the Late Triassic, carnivorous dinosaurs left behind footprints that would later fossilize. During the Cretaceous, however, the state was mostly covered by the Western Interior Seaway, which was home to huge ammonites and other marine invertebrates. During the Cenozoic, Oklahoma became home to creatures like bison, camels, creodonts, and horses. During the Ice Age, the state was home to mammoths and mastodons. Local Native Americans are known to have used fossils for medicinal purposes. The Jurassic dinosaur Saurophaganax maximus is the Oklahoma state fossil.
The Chickasha Formation, which is part of the El Reno Group, is a geologic formation in Oklahoma. It preserves fossils dating back to the Roadian stage of the Middle Permian. These include, among others, the dissorophoid temnospondyl Nooxobeia gracilis, the lepospondyl Diplocaulus parvus, and the captorhinid Rothianiscus robusta, initially called Rothia robusta by Everett C. Olson. Many of these fossils were indicated to have come from the Flowerpot Shale, but these actually come from the Chickasha Formation, according to the current nomenclature. The age of the formation was long debated because Olson based part of his argument on fragmentary fossils that he interpreted as therapsids, an interpretation that was not widely accepted. Worse, one of them, Watongia, was later shown to be a varanopid.
The Waggoner Ranch Formation is a geologic formation in northern Texas. It preserves fossils dating back to the Artinskian to Kungurian stages of the Permian period.
The Capitan Formation is a geologic formation found in western Texas and southeastern New Mexico. It is a fossilized reef dating to the Guadalupian Age of the Permian period.
The Cutoff Formation is a geologic formation in Texas and New Mexico, US. It preserves fossils dating back to the Permian period.
The San Angelo Formation is a geologic formation in Texas. It preserves fossils dating back to the Permian period. Along with the Chickasha Formation is one of the two geologically youngest formations in North America to preserve fossils of caseids, and it is the youngest one to preserve remains of undoubted sphenacodontids, namely, Dimetrodon angelensis.
The Pease River Group is a geologic group in Texas Red Beds. It preserves fossils dating back to the Permian period, including some of the geologically most recent continental and coastal vertebrates of the Permian in North America. These are preserved in the San Angelo Formation, which is probably of early Roadian age. They include several fragmentary fossils that Everett C. Olson interpreted as the earliest therapsids, an interpretation that has not been widely accepted.
The Coyote Butte Limestone (OR085) is a geologic formation in Oregon. It preserves fossils dating back to the Sakmarian to Kungurian stages of the Permian period, spanning an estimated 23 million years. The formation occurs in isolated buttes to the north; Triangulation Hill, and south; type locality and name giver Coyote Butte and Tuckers Butte, on either side of the Grindstone and Twelvemile Creeks in Crook County, Oregon.
The Talkeetna Formation is a geologic formation in Alaska. It preserves fossils dating back to the Early Jurassic period.
This timeline of Permian research is a chronological listing of events in the history of geology and paleontology focused on the study of earth during the span of time lasting from 298.9–252.17 million years ago and the legacies of this period in the rock and fossil records.
Toad Formation, Grayling Formation, and Toad-Grayling Formation are obsolete names for the strata of the Early to Middle Triassic Doig and Montney Formations. They were applied in the foothills and Rocky Mountains of northeastern British Columbia, on the western edge of the Western Canada Sedimentary Basin. Although the names are considered obsolete, their usage persists.