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25-955: Geological formation in the southern United States Ripley Formation Stratigraphic range : Upper Cretaceous [REDACTED] Rockground exposed in the Ripley Formation near Greenville, Alabama . Type Geological formation Unit of Selma Group Sub-units Cusseta Sand Member, McNairy Sand Member ( Chronister dinosaur site ) Underlies Prairie Bluff Chalk Formation Overlies Demopolis Chalk Formation Thickness 40 m (130 ft) to 175 m (574 ft) Lithology Primary Glauconitic sandstone Other Micaceous chalk Location Region Alabama , Georgia , Mississippi , Missouri , Tennessee Country United States Type section Named for Ripley, Mississippi The Ripley Formation

50-1059: A lack of accessible exposures. However, fossils have been unearthed including crocodile , hadrosaur , nodosaur , tyrannosaur , ornithomimid , dromaeosaur , and mosasaur remains have been recovered from the Ripley Formation. Paleofauna [ edit ] Hypsibema missouriensis ( hadrosaurid ) – "Caudal vertebrae, fragmentary dentary and predentary." cf. Gryposaurus sp. Nodosauridae sp. Tyrannosauroidea sp. cf. Albertosaurus sp. Dromaeosauridae sp. Possible Ornithomimidae indet. Eothoracosaurus mississippiensis Thoracosaurus neocesariensis Leidyosuchus sp. Adocus punctatus Naomichelys speciosa Trionyx sp. Habrosaurus sp. Amiidae sp. Lepisosteus sp. Platacodon nanus See also [ edit ] [REDACTED] Paleontology portal List of dinosaur-bearing rock formations List of fossil sites References [ edit ] ^ "Hypsibema missouriensis" . DinoData . 2011. Archived from

75-775: A proxy for the age at which a surface, such as an alluvial fan, was created. Burial dating uses the differential radioactive decay of 2 cosmogenic elements as a proxy for the age at which a sediment was screened by burial from further cosmic rays exposure. Luminescence dating techniques observe 'light' emitted from materials such as quartz, diamond, feldspar, and calcite. Many types of luminescence techniques are utilized in geology, including optically stimulated luminescence (OSL), cathodoluminescence (CL), and thermoluminescence (TL). Thermoluminescence and optically stimulated luminescence are used in archaeology to date 'fired' objects such as pottery or cooking stones and can be used to observe sand migration. Incremental dating techniques allow

100-487: A reference for newly obtained poles for the rocks with unknown age. For paleomagnetic dating, it is suggested to use the APWP in order to date a pole obtained from rocks or sediments of unknown age by linking the paleopole to the nearest point on the APWP. Two methods of paleomagnetic dating have been suggested: (1) the angular method and (2) the rotation method. The first method is used for paleomagnetic dating of rocks inside of

125-500: A rock, but merely places it within an interval of time at which that fossil assemblage is known to have coexisted. Both disciplines work together hand in hand, however, to the point where they share the same system of naming strata (rock layers) and the time spans utilized to classify sublayers within a stratum. The science of geochronology is the prime tool used in the discipline of chronostratigraphy , which attempts to derive absolute age dates for all fossil assemblages and determine

150-859: Is a geological formation in North America found in the U.S. states of Alabama , Georgia , Mississippi , Missouri , and Tennessee . The lithology is consistent throughout the layer. It consists mainly of glauconitic sandstone . It was formed by sediments deposited during the Maastrichtian stage of the Late Cretaceous . It is a unit of the Selma Group and consists of the Cusseta Sand Member, McNairy Sand Member and an unnamed lower member. It has not been extensively studied by vertebrate paleontologists, due to

175-616: Is a genus of gars in the family Lepisosteidae . Lepisosteus is known to be a freshwater fish. However, they do have the ability to survive in high salinity, and low oxygen water after gulping air. Lepisosteus prefers to reside in brackish and shallow slow-moving waters, living usually in schools . The habitat range of this genus ranges on the Eastern coast from the Gulf of Mexico in Florida north to Quebec . Habitats can be found in

200-702: Is also correct to say that fossils of the genus Tyrannosaurus have been found in the Upper Cretaceous Series. In the same way, it is entirely possible to go and visit an Upper Cretaceous Series deposit – such as the Hell Creek deposit where the Tyrannosaurus fossils were found – but it is naturally impossible to visit the Late Cretaceous Epoch as that is a period of time. Lepisosteus See text Lepisosteus

225-500: Is also often used as a dating tool in archaeology, since the dates of some eruptions are well-established. Geochronology, from largest to smallest: It is important not to confuse geochronologic and chronostratigraphic units. Geochronological units are periods of time, thus it is correct to say that Tyrannosaurus rex lived during the Late Cretaceous Epoch. Chronostratigraphic units are geological material, so it

250-1036: Is toxic to humans. There are no significant threats to these top predators other than habitat loss . On the IUCN Red List of Threatened Species , this genus is listed as Least Concerned. The fossil found in Northern Mexico shows that the family once may have been able to live in oceans. The genus consists of four species but cretaceous fossils have shown this family has ancient relatives. A. tropicus A. tristoechus A. spatula [REDACTED] L. oculatus L. platyrhincus L. osseus [REDACTED] L. platostomus [REDACTED] The currently recognized species are: Lepisosteus oculatus, Lepisosteus osseus, Lepisosteus platostomus, and Lepisosteus platyrhincus. Three species formerly classified in Lepisosteus ( tropical gar , Cuban gar , and alligator gar ) are now assigned to

275-532: The Ar/ Ar dating method can be extended into the time of early human life and into recorded history. Some of the commonly used techniques are: A series of related techniques for determining the age at which a geomorphic surface was created ( exposure dating ), or at which formerly surficial materials were buried (burial dating). Exposure dating uses the concentration of exotic nuclides (e.g. Be, Al, Cl) produced by cosmic rays interacting with Earth materials as

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300-670: The Missouri River Basin and Mississippi River drainage area, westward in the Rio Grande River basin of Southern Texas and Northern Mexico. There are also populations in the Great Lakes except for Lake Superior. Their range can occasionally reach out towards the Mobile Bay , Perdido Bay , and Mississippi Sound . These fish have ganoid scales on their elongated bodies with a single dorsal fin on

325-602: The United Kingdom Chalk Maastrichtian Stage of North America Hidden categories: Articles with short description Short description matches Wikidata Geochronology Geochronology is different in application from biostratigraphy, which is the science of assigning sedimentary rocks to a known geological period via describing, cataloging and comparing fossil floral and faunal assemblages. Biostratigraphy does not directly provide an absolute age determination of

350-436: The construction of year-by-year annual chronologies, which can be fixed ( i.e. linked to the present day and thus calendar or sidereal time ) or floating. A sequence of paleomagnetic poles (usually called virtual geomagnetic poles), which are already well defined in age, constitutes an apparent polar wander path (APWP). Such a path is constructed for a large continental block. APWPs for different continents can be used as

375-416: The exception of the radiocarbon method , most of these techniques are actually based on measuring an increase in the abundance of a radiogenic isotope, which is the decay-product of the radioactive parent isotope. Two or more radiometric methods can be used in concert to achieve more robust results. Most radiometric methods are suitable for geological time only, but some such as the radiocarbon method and

400-543: The geologic history of the Earth and extraterrestrial bodies . By measuring the amount of radioactive decay of a radioactive isotope with a known half-life , geologists can establish the absolute age of the parent material. A number of radioactive isotopes are used for this purpose, and depending on the rate of decay, are used for dating different geological periods. More slowly decaying isotopes are useful for longer periods of time, but less accurate in absolute years. With

425-441: The objects until the yolk sac is absorbed which usually takes about 9 days. After the yolk sac of an egg is absorbed, the roe hatches. Hatchlings stabilize to a horizontal position, take their first aerial breath, and begin feeding. Because Lepisosteus has evolved to be a top predator, they are voracious eaters that eat a variety of other freshwater fish and crustaceans such as Ictiobus and Blue crabs . Adults will float toward

450-991: The original on November 18, 2015 . Retrieved January 12, 2011 . ^ Fix, Michael F.; Darrough, Guy (2004). "Dinosauria and associated vertebrate fauna of the Late Cretaceous Chronister site of southeast Missouri" . Abstracts with Programs . 36 (3). Geological Society of America : 14. Archived from the original on 2012-03-31 . Retrieved 2016-08-28 . ^ Holloway, Brad (January 31, 2005). "Rock of ages – Museum reveals fossil find in Bollinger County" . Southeast Missourian . Southeast Missourian . Retrieved January 14, 2011 . ^ "Missouri Dinosaur - Chronister Vertebrate Site - Bruce Sinchcomb" . www.lakeneosho.org . Retrieved 2021-12-12 . ^ Brochu, Christopher A. (2004-09-10). "A new Late Cretaceous gavialoid crocodylian from eastern North America and

475-1157: The original on September 13, 2011 . Retrieved January 12, 2011 . ^ Kiernan, Caitlin R. (2002). "Stratigraphic distribution and habitat segregation of mosasaurs in the Upper Cretaceous of western and central Alabama, with an historical review of Alabama mosasaur discoveries". Journal of Vertebrate Paleontology . 22 (1): 91–103. doi : 10.1671/0272-4634(2002)022[0091:SDAHSO]2.0.CO;2 . S2CID   130280406 . ^ "Table 20.1," in Weishampel, et al. (2004). Page 443. ^ Parris, David. "CHRONISTER SITE INVESTIGATIONS: NEW INFORMATION ON THE CRETACEOUS OF MISSOURI" . Retrieved 6 October 2006 . ^ Bruns, Michael E. "NEW APPALACHIAN ARMORED DINOSAUR MATERIAL (NODOSAURIDAE, ANKYLOSAURIA) FROM THE MAASTRICHTIAN RIPLEY FORMATION OF ALABAMA" . The Geological Society of America . Retrieved 1 April 2016 . ^ Powers, Marc (February 19, 2004). "A bone to pick for Missouri" . Southeast Missourian . Southeast Missourian. Archived from

500-822: The phylogenetic relationships of thoracosaurs" . Journal of Vertebrate Paleontology . 24 (3): 610–633. doi : 10.1671/0272-4634(2004)024[0610:anlcgc]2.0.co;2 . ISSN   0272-4634 . S2CID   131176447 . ^ Kenneth., Carpenter (1983). Thoracosaurus neocesariensis (De Kay, 1842) (Crocodylia: Crocodylidae) from the Late Cretaceous Ripley Formation of Mississippi . [s.n.] OCLC   895629547 . Retrieved from " https://en.wikipedia.org/w/index.php?title=Ripley_Formation&oldid=1188483154 " Categories : Cretaceous Mississippi Cretaceous Alabama Cretaceous Georgia (U.S. state) Cretaceous Missouri Cretaceous geology of Tennessee Sandstone in

525-447: The posterior side approximately one inch from their caudal fin . Depending on the clarity of the water, Lepisosteus colors will change. In clear water they can have bright colors of green and silvery-white; alternatively if the water is brackish and cloudy, their colors will be more of a brown hue . Hatchlings are approximately 8–10 mm in size. The average full-grown length of Lepisosteus varies from 34 to 78 inches depending on

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550-426: The same age and of such distinctive composition and appearance that, despite their presence in different geographic sites, there is certainty about their age-equivalence. Fossil faunal and floral assemblages , both marine and terrestrial, make for distinctive marker horizons. Tephrochronology is a method for geochemical correlation of unknown volcanic ash (tephra) to geochemically fingerprinted, dated tephra . Tephra

575-700: The same continental block. The second method is used for the folded areas where tectonic rotations are possible. Magnetostratigraphy determines age from the pattern of magnetic polarity zones in a series of bedded sedimentary and/or volcanic rocks by comparison to the magnetic polarity timescale. The polarity timescale has been previously determined by dating of seafloor magnetic anomalies, radiometrically dating volcanic rocks within magnetostratigraphic sections, and astronomically dating magnetostratigraphic sections. Global trends in isotope compositions, particularly carbon-13 and strontium isotopes, can be used to correlate strata. Marker horizons are stratigraphic units of

600-678: The species. In comparison to their long snouts, Lepisosteus have relatively small heads; however, their mouths full of sharp teeth. Lepisosteus is a slow-growing genus generally living a long time. Female gars take 6 years to reach sexual maturity, grow larger, and live up to 22 years. Male gars reach maturity around 3 or 4 years after hatching. The males do not often live longer than 11 years. The Longnose Gar will migrate upstream to smaller streams with faster-moving water to spawn and lay eggs. Fish of this genus that are newly hatched will attach themselves vertically to submerged objects by an adhesive disc on their snout. The youth stay attached to

625-487: The surface of streams to scout prey that are below them while younger fish in this genus will hide in submersed vegetation to ambush hunt. Studies have found this native North American species is a predator of invasive Asian Carp. The Lepisosteus genus enjoys living in shallow water similar to the habitat of the Invasive Asian Carp . This genus is not generally used for recreational hunting because their roe

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