The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy. In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous series. Campanian spans the time from 83.6 to 72.1 million years ago. It is preceded by the Santonian and it is followed by the Maastrichtian; the Campanian was an age. The morphology of some of these areas has been preserved: it is an unconformity beneath a cover of marine sedimentary rocks; the Campanian was introduced in scientific literature by Henri Coquand in 1857. It is named after the French village of Champagne in the département Charente-Maritime; the original type locality was an outcrop near the village of Aubeterre-sur-Dronne in the same region. Due to changes of the stratigraphic definitions, this section is now part of the Maastrichtian stage; the base of the Campanian stage is defined as a place in the stratigraphic column where the extinction of crinoid species Marsupites testudinarius is located.
The top of the Campanian stage is defined as the place in the stratigraphic column where the ammonite Pachydiscus neubergicus first appears. The Campanian can be subdivided into Lower and Upper subages. In the Tethys domain, the Campanian encompasses six ammonite biozones, they are, from young to old: zone of Nostoceras hyatti zone of Didymoceras chayennense zone of Bostrychoceras polyplocum zone of Hoplitoplacenticeras marroti/Hoplitoplacenticeras vari zone of Delawarella delawarensis zone of Placenticeras bidorsatum During the Campanian age, a radiation among dinosaur species occurred. In North America, for example, the number of known dinosaur genera rises from 4 at the base of the Campanian to 48 in the upper part; this development is sometimes referred to as the "Campanian Explosion". However, it is not yet clear if the event is artificial, i.e. the low number of genera in the lower Campanian can be caused by a lower preservation chance for fossils in deposits of that age. The warm climates and large continental area covered in shallow sea during the Campanian favoured the dinosaurs.
In the following Maastrichtian stage, the number of North American dinosaur genera found is 30% less than in the upper Campanian. Animals that lived in the Campanian include: David J. Varrichio observes that during the late Campanian Alberta and Montana had similar theropods despite significant differences in the types of herbivorous dinosaur faunas. Gradstein, F. M.. G. & Smith, A. G.. Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur dinosaurs from Montana. Pp. 42–57 in D. H. Tanke and K. Carpenter, Mesozoic Vertebrate Life. Indiana University Press, Indiana. Weishampel, D. B.. M.. A.. M. P. & Noto, C. N.. B.. GeoWhen Database - Campanian Late Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS Stratigraphic chart of the Late Cretaceous, at the website of Norges Network of offshore records of geology and stratigraphy Campanian Microfossils: 75+ images of Foraminifera
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma. The Turonian underlies the Coniacian stage. At the beginning of the Turonian an anoxic event took place, called the Cenomanian-Turonian boundary event or the "Bonarelli Event"; the Turonian was defined by the French paleontologist Alcide d'Orbigny in 1842. Orbigny named it after the French city of Tours in the region of Touraine, the original type locality; the base of the Turonian stage is defined as the place where the ammonite species Wutinoceras devonense first appears in the stratigraphic column. The official reference profile for the base of the Turonian is located in the Rock Canyon anticline near Pueblo, Colorado; the top of the Turonian stage is defined as the place in the stratigraphic column where the inoceramid bivalve species Cremnoceramus rotundatus first appears. The Turonian is sometimes subdivided in Lower/Early and Upper/Late substages or subages.
In the Tethys domain, it contains the following ammonite biozones: zone of Subprionocyclus neptuni zone of Collignoniceras woollgari zone of Mammites nodosoides zone of Watinoceras coloradoense or Watinoceras devonense Other important index fossils are species of the inoceramid genus Inoceramus. Inoceramids are bivalve Mollusca related to today's mussels. Gradstein, F. M.. G. & Smith, A. G.. Kennedy, W. J.. & Cobban, W. A.. S. A. Episodes 28: pp 93–104. GeoWhen Database - Turonian Late Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS Stratigraphic charts of the Cretaceous: and, at the website of Norges Network of offshore records of geology and stratigraphy Turonian Microfossils: 48 images of Foraminifera
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 113.0 ± 1.0 Ma, approximately. The Aptian precedes the Albian, all part of the Lower/Early Cretaceous; the Aptian overlaps the upper part of the regionally used stage Urgonian. The Selli Event known as OAE1a, was one of two oceanic Anoxic events in the Cretaceous period, which occurred around 120 Ma and lasted 1 to 1.3 million years. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma; the Aptian was named after the small city of Apt in the Provence region of France, known for its crystallized fruits. The original type locality is in the vicinity of Apt; the Aptian was introduced in scientific literature by French palaeontologist Alcide d'Orbigny in 1840. The base of the Aptian stage is laid at magnetic anomaly M0r. A global reference profile for the base had in 2009 not yet been appointed.
The top of the Aptian is at the first appearance of coccolithophore species Praediscosphaera columnata in the stratigraphic record. In the Tethys domain, the Aptian contains eight ammonite biozones: zone of Hypacanthoplites jacobi zone of Nolaniceras nolani zone of Parahoplites melchioris zone of Epicheloniceras subnodosocostatum zone of Duffrenoyia furcata zone of Deshayesites deshayesi zone of Deshayesites weissi zone of Deshayesites oglanlensisSometimes the Aptian is subdivided in three substages or subages: Bedoulian and Clansayesian. Examples of rock units formed during the Aptian are: Antlers Formation, Cedar Mountain Formation, Cloverly Formation, Elrhaz Formation, Jiufotang Formation, Little Atherfield, Mazong Shan, Potomac Formation, Santana Formation, Twin Mountains Formation, Xinminbao Group and Yixian Formation. Eogaudryceras Georgioceras Lithancylus Pictetia Salfeldiella Zuercherella Lower Ammonitoceras Australiceras Cheloniceras Cicatrites Colombiceras Dufrenoya Eotetragonites Helicancylus Melchiorites Parahoplites Procheloniceras Prodeshayesites Pseudosaynella Roloboceras Shastoceras Upper Acanthohoplites Acanthoplites Ammonoceratites Argonauticeras Beudanticeras Burckhardites Cloioceras Desmoceras Diadochoceras Diodochoceras Eodouvilleiceras Epancyloceras Epicheloniceras Gabbioceras Gargasiceras Gyaloceras Hamites Hulenites Hypacanthoplites Jauberticeras Kazanskyella Knemiceras Mathoceras Mathoceratites Megatyloceras Metahamites Miyakoceras Neosilesites Nodosohoplites Nolaniceras Protacanthoplites Protanisoceras Sinzovia Somalites Tetragonites Theganoceras Trochleiceras Tropaeum Uhligella Conoteuthis Vectibelus Lower Parahibolites Peratobelus Tetrabelus Carinonautilus Heminautilus Upper Zhuralevia Upper Euphylloceras Upper Adygeya Naefia Boluochia zhengi Changchengornis hengdaoziensis Chaoyangia beishanensis Confuciusornis sanctus Cuspirostrisornis houi Jeholornis prima Jixiangornis orientalis Largirostrornis sexdentoris Longchengornis sanyanensis Longipteryx chaoyangensis Sapeornis chaoyangensis Sinornis santensis/Cathayornis yandica Songlingornis linghensis Yanornis martini Yixianornis grabaui Sarcosuchus Hybodus Jinanichthys longicephalus Lycoptera davidi Lycoptera muroii Peipiaosteus pani Protosephurus liui Sinamia zdanskyi Amblydectes Anhanguera Araripedactylus dehmi Araripesaurus castilhoi Arthurdactylus conandoylei Boreopterus cuiae Brasileodactylus araripensis Cearadactylus atrox Chaoyangopterus zhangi Dsungaripterus weii Dsungaripterus brancai Eoazhdarcho liaoxiensis Eopteranodon lii Gegepterus changi Haopterus gracilis Hongshanopterus lacustris Huaxiapterus benxiensis Huaxiapterus corollatus Huaxiapterus jii Istiodactylus latidens Istiodactylus sinensis Jidapterus edentus Liaoningopterus gui Liaoxipterus brachyognathus Lonchodectes Longchengpterus zhaoi Ludodactylus sibbicki Nemicolopterus crypticus Nurhachius ignaciobritoi Ornithocheirus simus Ornithocheirus mesembrinus Pricesaurus megalodon Santanadactylus Sinopterus dongi Sinopterus gui Tapejara navigans Tapejara wellnhoferi Thalassodromeus sethi Tropeognathus mesembrinus Tropeognathus robustus Tupandactylus imperator Aptian extinction Gradstein, F.
M.. G. & Smith, A. G.. D'Orbigny, A. C. V. M.. GeoWhen Database - Aptian Mid-Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS Stratigraphic charts of the Lower Cretaceous: and, at the website of Norges Network of offshore records of geology and stratigraphy
The Purbeck Group is an Upper Jurassic to Lower Cretaceous lithostratigraphic group in south-east England. The name is derived from the district known as the Isle of Purbeck in Dorset where the strata are exposed in the cliffs west of Swanage; the Purbeck Group is famous for its fossils of early mammals. This sequence of rocks has gone by various names in the past including amongst others the Purbeck Beds, Purbeck Formation, Purbeck Limestone Formation and Purbeck Stone. Rocks of this age have in the past been called the Purbeckian stage by European geologists; the Purbeckian corresponds with the Tithonian to Berriasian stages of the internationally used geologic timescale. The Purbeck Group outcrops follow the line of the Jurassic outcrop from Dorset, through the Vale of Wardour, Garsington and Aylesbury. In East Sussex, the Purbeck Group outcrops at three locations north and northwest west of Battle, East Sussex and at Netherfield, they occur at several other locations east of Heathfield, East Sussex and at Beak's Wood near Burwash.
Deposits of evaporite minerals such as gypsum and anhydrite, within the Purbeck Group are mined and processed in Mountfield, East Sussex. In Lincolnshire they are represented in part by the Spilsby Sands and in Yorkshire by portions of the Speeton Clay; the rocks predominantly comprise calcareous mudstones though include clays and marls with marly and shelly limestones, occasional oolitic and sandy strata, evaporites. Nodules of chert are present in some of the limestones; the thickness of the formation in Wiltshire is 80 to 90 ft, but in Dorset it is between 45 and 120 metres thick. In the Weald of East Sussex the Purbeck Group has a typical thickness of between 186 metres. In most places the Purbeck Group rests conformably upon the Portland Group and it is conformably overlaid by the Wealden Group. In the past, many geologists have ranged the Purbeck Group with the overlying Lower Cretaceous Wealden Group on account of the similarity of its fresh-water faunas. Contemporaneous rocks are present in the neighbourhood of Boulogne-sur-Mer, where they are characterized by thin limestones with Cyrena and gypsiferous marls.
These French outcrops occur, just in the core of the Weald-Artois anticline. Purbeckian aged deposits occur further south in the Charente. In north-west Germany three subdivisions are recognized in strata of the same age: in descending order Purbeck Kalk, Serpulit and Münder Mergel; the Purbeck Group in Dorset is now divided into three formations, the Lulworth Formation and the overlying Durlston Formation in the south. A third underlying formation, the Haddenham Formation, is identified in Wiltshire and Buckinghamshire. Within the Vectian Basin, the Durlston Formation is further divided into a lower'Stair Hole Member' and an upper'Peveril Point Member'; the Lulworth Formation is divided in Dorset into a lower'Mupe Member', a middle'Ridgeway Member' and an upper'Worbarrow Tout Member'. In East Sussex the Purbeck Group is formally subdivided into the Blues and Greys Limestones members The sequence was traditionally divided into three, though along different lines viz. Upper and Lower; the Upper Purbeck comprises 50 to 60 ft. of fresh-water clays and shales with limestones, the Purbeck marble and Unio-bed, in the lower part.
The Middle division thin limestones with shaly partings, contains the principal building stones of the Swanage district. The Lower Purbeck consists of fresh-water and terrestrial deposits and limestones with several fossil soils known as dirt beds; this division is extensively exposed on the Isle of Portland, where many of the individual beds are known by distinctive names. The chief building stones of Upwey belong to this part of the Purbeck Group. No zonal fossil has been recognized for the British Purbeckian strata, but the horizon is equivalent to that of Pensphinctes transilorius of the European continent; the Purbeckian equivalents of Spilsby and Speeton are in the zone of Belemnites lateralis. Other marine fossils are Hemicidaris purbeckensis and Ostrea distonta, the latter being abundant in the Cinder bed of the Middle Purbeck; the fresh-water mollusca include Viviparus, Melanopsis, Cyrena. A large number of insect genera has been found in the Lower Purbeck Group. Dinosaurs, Cimoliosaurus, the plesiosaurs and the chelonians are representative reptiles.
The mammals determined from lower jaws, found in the beds mentioned above include Plagiaulax, Stylodon, Triconodon and several others. The isopod crustacean Archeoniscus brodei is common in the Purbeck of the Vale of Wardour. Reptile remains diagnostic to the genus level are among the fossils that have been recovered from the formation. Fossil eggs referable to the oogenus Mycomorphooli
Global Boundary Stratotype Section and Point
A Global Boundary Stratotype Section and Point, abbreviated GSSP, is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted by the International Commission on Stratigraphy, a part of the International Union of Geological Sciences. Most, but not all, GSSPs are based on paleontological changes. Hence GSSPs are described in terms of transitions between different faunal stages, though far more faunal stages have been described than GSSPs; the GSSP definition effort commenced in 1977. As of 2012, 64 of the 101 stages that need a GSSP have been formally defined. A geologic section has to fulfill a set of criteria to be adapted as a GSSP by the ICS; the following list summarizes the criteria: A GSSP has to define the lower boundary of a geologic stage. The lower boundary has to be defined using a primary marker. There should be secondary markers; the horizon in which the marker appears should have minerals.
The marker has to have regional and global correlation in outcrops of the same age The marker should be independent of facies. The outcrop has to have an adequate thickness Sedimentation has to be continuous without any changes in facies The outcrop should be unaffected by tectonic and sedimentary movements, metamorphism The outcrop has to be accessible to research and free to access; this includes that the outcrop has to be located where it can be visited has to be kept in good condition, in accessible terrain, extensive enough to allow repeated sampling and open to researchers of all nationalities. The Precambrian-Cambrian boundary GSSP at Fortune Head, Newfoundland is a typical GSSP, it is set aside as a nature preserve. A continuous section is available from beds that are Precambrian into beds that are Cambrian; the boundary is set at the first appearance of a complex trace fossil Treptichnus pedum, found worldwide. The Fortune Head GSSP is unlikely to be built over. Nonetheless, Treptichnus pedum is less than ideal as a marker fossil as it is not found in every Cambrian sequence, it is not assured that it is found at the same level in every exposure.
In fact, further eroding its value as a boundary marker, it has since been identified in strata 4m below the GSSP! However, no other fossil is known. There is no radiometrically datable bed at the boundary at Fortune Head, but there is one above the boundary in similar beds nearby; these factors have led some geologists to suggest. Once a GSSP boundary has been agreed upon, a "golden spike" is driven into the geologic section to mark the precise boundary for future geologists; the first stratigraphic boundary was defined in 1977 by identifying the Silurian-Devonian boundary with a bronze plaque at a locality called Klonk, northeast of the village of Suchomasty in the Czech Republic. GSSPs are sometimes referred to as Golden Spikes; because defining a GSSP depends on finding well-preserved geologic sections and identifying key events, this task becomes more difficult as one goes farther back in time. Before 630 million years ago, boundaries on the geologic timescale are defined by reference to fixed dates, known as "Global Standard Stratigraphic Ages".
Body form European Mammal Neogene Fauna Geologic time scale New Zealand geologic time scale List of GSSPs North American Land Mammal Age Type locality Hedberg, H. D. International stratigraphic guide: A guide to stratigraphic classification and procedure, New York, John Wiley and Sons, 1976 International Stratigraphic Chart from the International Commission on Stratigraphy GSSP table with pages on each ratified GSSP from the ICS Subcommission for Stratigraphic Information USA National Park Service Washington State University Web Geological Time Machine Eon or Aeon, Math Words - An alphabetical index The Global Boundary Stratotype Section and Point: overview Chart of The Global Boundary Stratotype Sections and Points: chart Table of Global Boundary Stratotype Sections and Points with links to summary pages for each one: chart GSSPs and Continental drift 3D views Geotime chart displaying geologic time periods compared to the fossil record - Deals with chronology and classifications for laymen
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of Upper Cretaceous series, it spans the time between 83.6 ± 0.7 mya. The Santonian is followed by the Campanian; the Santonian stage was established by French geologist Henri Coquand in 1857. It is named after the city of Saintes in the region of Saintonge, where the original type locality is located; the base of the Santonian stage is defined by the appearance of the inoceramid bivalve Cladoceramus undulatoplicatus. Its top is marked by the extinction of the crinoid Marsupites testudinarius. In 2009, a GSSP for both base and top had not yet been appointed; the Santonian is sometimes subdivided into Lower and Upper substages. In the Tethys domain the Santonian is coeval with a single ammonite biozone: that of Placenticeras polyopsis. Biostratigraphy based on inoceramids, nanoplankton or forams is more detailed. Magnoliopsida Advanced dicotyledons Droseraceae: †Palaeoaldrovanda Gradstein, F. M.. G. & Smith, A.
G.. GeoWhen Database - Santonian Late Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS Stratigraphic chart of the Late Cretaceous, at the website of Norges Network of offshore records of geology and stratigraphy
Crocodylomorpha is a group of archosaurs that includes the crocodilians and their extinct relatives. During Mesozoic and early Cenozoic times, crocodylomorphs were far more diverse. Triassic forms were small built, active terrestrial animals; these were supplanted during the early Jurassic by various marine forms. The Later Jurassic and Cenozoic saw a wide diversity of terrestrial and semiaquatic lineages. "Modern" crocodilians do not appear until the Late Cretaceous. Among the largest crocodylomorphs were: When their extinct species and stem group are examined, the crocodylian lineage proves to have been a diverse and adaptive group of reptiles. Not only are they an ancient group of animals – at least as old as the dinosaurs – they evolved into a great variety of forms; the earliest forms, the sphenosuchians, evolved during the Late Triassic, were gracile terrestrial forms built like greyhounds. During the Jurassic and the Cretaceous, marine forms in the family Metriorhynchidae, such as Metriorhynchus, evolved forelimbs that were paddle-like and had a tail similar to modern fish.
Dakosaurus andiniensis, a species related to Metriorhynchus, had a skull, adapted to eat large marine reptiles. Several terrestrial species during the Cretaceous were herbivorous, such as Simosuchus clarki and Chimaerasuchus paradoxus. A number of lineages during the Cenozoic became wholly terrestrial predators. All known living and extinct crocodiles were indiscriminately lumped into the order Crocodilia. However, beginning in the late 1980s, many scientists began restricting the order Crocodilia to the living species and close extinct relatives such as Mekosuchus; the various other groups, known as Crocodilia were moved to Crocodylomorpha and the more restrictive Crocodyliformes. Crocodylomorpha has been given the rank of superorder in some 21st century studies; the old Crocodilia was subdivided into the suborders: Eusuchia: true crocodilies Mesosuchia:'middle' crocodiles Thalattosuchia: sea crocodiles Protosuchia: first crocodilesMesosuchia is a paraphyletic group as it does not include eusuchians.
Mesoeucrocodylia was the name given to the clade that contains eusuchians. Below is a cladogram modified from Bronzati; the previous definitions of Crocodilia and Eusuchia did not convey evolutionary relationships within the group. The only order-level taxon, considered valid is Crocodilia in its present definition. Prehistoric crocodiles are represented by many taxa, but since few major groups of the ancient forms are distinguishable, a conclusion on how to define new order-level clades is not yet possible.. The Crocodylomorpha comprise a variety of forms and sizes, which occupied a range of habitats; as with most amniotes, Crocodylomorphs were and are oviparous, laying eggs in a nest or mound, known from strata as old as the Late Jurassic. Adult size varies from about 55 cm long in Knoetschkesuchus to much larger dimensions, as in Sarcosuchus. Most crocodylomorphs were carnivores, but many lineages evolved to be obligate piscivores, such as the extant gharials. Benton, M. J. Vertebrate Palaeontology, 3rd ed. Blackwell Science Ltd Hay, O. P. 1930.
Second Bibliography and Catalogue of the Fossil Vertebrata of North America. Carnegie Institution Publications, Washington, 1, 990 pp. Crocodylomorpha - webpages by Ross Elgin on the University of Bristol server Major subgroups classification Crocodylomorpha from Palaeos Technical definition