Where results make sense

About us   |   Why use us?   |   Reviews   |   PR   |   Contact us

Devonian - Wikipedia, the free encyclopedia The Devonian is a geologic period of the Paleozoic era. The paleogeography was dominated by the supercontinent of Gondwana to the south, the continent of Siberia to the north, and the early formation of the small supercontinent of Euramerica in the middle. The continent Euramerica (or Laurussia) was created in the early Devonian by the collision of Laurentia and Baltica, which rotated into the natural dry zone along the Tropic of Capricorn, which is formed as much in Paleozoic times as nowadays by the convergence of two great airmasses, the Hadley cell and the Ferrel cell. en.wikipedia.org /wiki/Devonian   (1306 words)

The Geology of Ohio--The Devonian The Devonian Period was an important episode in the history of the Earth. The Devonian System was named in 1839 by Roderick Murchison and Adam Sedgwick for a series of greatly disturbed sedimentary rocks that lay between the Silurian and the Carboniferous rocks in Britain. With one exception, all of the outcropping Devonian rocks in the state are of Middle or Late Devonian age. www.dnr.state.oh.us /geosurvey/oh_geol/99_No_1/devonian1.htm   (1111 words)

Palaeos Paleozoic : Devonian : The Late Devonian Period Late Devonian stratigraphy has been intensively studied; and there seems to be considerable agreement on basics, particularly for the Euramerican world. "The Devonian Period was characterized by major changes in both the terrestrial biosphere e g the evolution of trees and seed plants and the appearance of multi-storied forests, and in the marine biosphere an extended biotic crisis that decimated tropical marine benthos, especially the stromatoporoid tabulate coral reef community. The first tetrapod skeletons are known from the Late Devonian of Greenland, but other traces of Devonian fossil evidence, such as some tetrapod footprints and fragmentary remains from Australia, hint at a much greater distribution of Devonian tetrapods than is currently revealed in the fossil record. www.palaeos.com /Paleozoic/Devonian/LateDev.html   (1468 words)

Paleobiology 4 The late Paleozoic, the subject of this chapter, saw the spread of plant life over the land surface and the emergence and diversification of amphibians and their descendants the reptiles as dominant animal life on land. The earliest terrestrial vertebrate fossils are from the late Devonian. Glacial tillites and other geological evidence of late Permian age occur in Australia, Siberia and in the North Sea are interpreted as proof of the existence of large continental glaciers at the close of the Permian. www.emc.maricopa.edu /faculty/farabee/biobk/BioBookPaleo4.html   (6474 words)

Devonian Devonian is a time interval from 416 to 359 Ma in the Palaeozoic era. Invertebrates of the Devonian period are essentially of types established in the Ordovician (505-440 Ma). The first spiders, millipedes and insects appear in the Devonian, but the Devonian is called the "Age of Fishes" since freshwater and marine varieties proliferate. www.geosci.usyd.edu.au /users/prey/FieldTrips/Yass04/Devonian.html   (1996 words)

Devonian Summary Then, in the Devonian, came the fish, which developed jaws and were such successful competitors that the Agnathans were reduced almost to extinction, with only the lampreys and hagfish as their descendants. The Early Devonian Epoch is the most ancient, followed in sequence by the Middle Devonian Epoch, and the Late Devonian Epoch. The continent Euramerica (or Laurussia) was created in the early Devonian by the collision of Laurentia and Baltica, which rotated into the natural dry zone along the Tropic of Cancer, which is formed as much in Paleozoic times as nowadays by the convergence of two great airmasses, the Hadley cell and the Ferrel cell. www.bookrags.com /Devonian   (2087 words)

Palaeos Paleozoic: Devonian: The Devonian Period - 1 Historically, the Devonian has been regarded as largely warm and equable, with a disastrous drop in temperatures in the Late Devonian leading to the Frasnian-Famennian "mass extinction(s)." The reason for this impression may be that most work was traditionally done on the "Old Red Continent," i.e. The climate of the Early Devonian is rather strongly zonal, with a narrow equatorial tropical belt, broad subtropical arid zones extending to about 35° latitude, and a temperate zones extending essentially to the poles. The plant assemblage itself is interesting for the Early Devonian in that its members are not recognized or recorded elsewhere in Euramerica. www.palaeos.com /Paleozoic/Devonian/Devonian.htm   (1672 words)

Devonian Times - Mass Extinction The timing and duration of the Late Devonian mass extinction(s), however, are subject to considerable debate and a variety of interpretations. The primary Devonian reef-builders (tabulate corals and stromatoporoids) never truly recovered from the extinctions and the changes in reef ecology were profound. Devonian marine deposits are notable in part for the widespread occurrence of fl shales in the shallow inland seas of North America and Eurasia. www.devoniantimes.org /opportunity/massExtinction.html   (890 words)

Devonian Period The Devonian was proposed by Roderick I. Murchison and Adam Sedgewick in 1840. The base of the Devonian is defined immediately at the first appearance of the graptolite species Monograptus uniformis in the rhythmically alterating limestones and calcareous shales of ‘Bed 20’ in the Klonk Section, which is located about 35km southwest of Prague, near the village of Suchomasty, in the Czech Republic. The youngest Devonian and earliest Carboniferous beds are characterized by a sequence of predominantly biodetrital oolitic limestone within a pelagic matrix of shale and cephalopod bearing calcilutites. www.peripatus.gen.nz /paleontology/Devonian.html   (1266 words)

Late Devonian extinction - Wikipedia, the free encyclopedia The Late Devonian extinction was one of five major extinction events in the history of the Earth's biota. Although it is clear that there was a massive loss of biodiversity towards the end of the Devonian, the extent of time during which these events took place is uncertain, with estimates ranging from 500 thousand to 15 million years, the latter being the full length of the Famennian. The late Devonian crash in biodiversity was more drastic than the familiar extinction event that closed the Cretaceous: a recent survey (McGhee 1996) estimates that 22 percent of all the families of marine animals (largely invertebrates) were eliminated, the category of families offering a broad range of real structural diversity. en.wikipedia.org /wiki/Late_Devonian_extinction   (824 words)

Palaeontology - Zerina Johanson Late Devonian fish fauna of Canowindra, New South Wales. Late Devonian fishes from Eden, New South Wales. A revision of the Late Cretaceous (Campanian) marsupial Iqualadelphis lactea Fox, 1987. www.amonline.net.au /palaeontology/staff/johanson.htm   (742 words)

Devonian   (Site not responding. Last check: 2007-09-08) ''Disambiguation: Devonian is also an adjective relating to the English county of Devon or the people there.'' The Devonian is a geologic period of the Paleozoic era. According to the International Commission on Stratigraphy (Ogg, 2004), the Devonian extends from the end of the Silurian Period 416.0 ± 2.8 million years ago (Mya), to the beginning of the Carboniferous Period 359.2 ± 2.5 Mya (in North America, the beginning of the Mississippian subperiod of the Carboniferous). Even more rarely the Devonian is also known as the Old Red Age, after the Red and brown terrestrial deposits known in Britain as the "Old Red Sandstone" in which these early discoveries were found. devonian.iqnaut.net   (899 words)

Palaeontology - Late Devonian fauna from the Hunter Siltstone near Grenfell, New South Wales Late Devonian fauna from the Hunter Siltstone near Grenfell, New South Wales The locality was first discovered in the late 1970s by a student doing a field work project in the area. Biogeographic relationships of the Grenfell fauna and eastern Australia during the Late Devonian were largely based on the distribution of the Sinolepidae. www.austmus.gov.au /palaeontology/field_sites/grenfell.htm   (556 words)

Strata of Devonian Age, Kentucky Geological Survey site   (Site not responding. Last check: 2007-09-08) Devonian strata consits of limestones and dolostones and a thick deposit of dark gray to fl shale. During the Late Devonian, muds were deposited beneath a sea that covered most of the eastern United States. The gas reservoir is in Devonian shales buried deep beneath the surface. www.uky.edu /KGS/geoky/devonian.htm   (243 words)

1999 Young Naturalist Awards | American Museum of Natural History By the end of the Devonian period, the sea's eastern shore was in western New York. The Gowanda Shale was deposited on the slope of the sea floor of the Catskill Sea during the Late Devonian (Tesmer 1963). The Ellicott Shale was deposited on the shelf of the Catskill Sea during the Late Devonian (Tesmer 1963). www.amnh.org /nationalcenter/youngnaturalistawards/1999/blood.html   (2455 words)

Chapter 9, part 1, Lecture Notes, Late Paleozoic Events, Levin: The Earth Through Time - Wiley During the Late Paleozoic, the land was colonized by large plants (including spore-bearing trees and seed ferns), and by large vertebrates (amphibians and reptiles). During the Late Paleozoic, the continents were gradually assembled into the great supercontinent of Pangea (sometimes spelled Pangaea), from the Greek, meaning "all land". As the Late Paleozoic began, note that during the latter part of the Early Devonian, the continents were fairly fragmented and separate, particularly in the Northern Hemisphere. www3.interscience.wiley.com:8100 /legacy/college/levin/0470000201/chap_tutorial/ch09/chapter09-1.html   (478 words)

Ashouri   (Site not responding. Last check: 2007-09-08) Ashouri, A-R. Devonian – Carboniferous boundary and conodonts in the Ozbak-Kuh Mountains. Icriodus and Polygnathus conodont fauna; Late Devonian from east and Middle-Late Devonian from north Iran. Palmatolepis (conodonta; Late Devonian) from the Tabas region, east Iran. sds.uta.edu /sds18/Ashouri.htm   (637 words)

New Chonostrophiid brachiopods from the Famennian (Late Devonian) of the Santanghu Basin, Xinjiang, Northwest China ... New Chonostrophiid brachiopods from the Famennian (Late Devonian) of the Santanghu Basin, Xinjiang, Northwest China ABSTRACT-Two new genera of the Chonostrophiidae are proposed herein to accommodate the resupinate shells from the Famennian sediments of the Late Devonian in the Santanghu Basin of the Balikun area, Xinjiang Province, northwestern China. In the summer of 1995, one of the authors (Z. C.) investigated the Late Paleozoic rocks of the Santanghu Basin (China) with a research team of Nanjing Institute of Palaeontology and Geology, Chinese Academy of Sciences, for the purposes of petroleum exploration. www.findarticles.com /p/articles/mi_qa3790/is_200203/ai_n9078164   (1002 words)

The Devonian Mass Extinction   (Site not responding. Last check: 2007-09-08) During the Devonian the world's oceans were dominated by reef-builders such as the stromatoporoids, and corals, and some of the world's largest reef complexes were built. The Devonian mass extinction occurred during the latter part of the Devonian at the Frasnian - Famennian boundary. This late Devonian crisis affected these organisms so severely that reef-building was relatively uncommon until the evolution of the scleractinian (modern) corals in the Mesozoic era. park.org /Canada/Museum/extinction/devmass.html   (225 words)

American Scientist Online - Planetary Realignment Next, McGhee documents the breadth of the Late Devonian crisis by discussing the victims and survivors in each of the marine and terrestrial groups. Employing our current map of the Late Devonian world, McGhee identifies five ecological signals in the extinction data: global scope, greater extinction in equatorial regions, latitudinal compression of the ranges of low-latitude survivors, higher extinction in shallow-water marine environments, and more severe losses in marine than freshwater environments. Although explanations invoking multiple causes may be much harder to test, I would have appreciated an explicit consideration of the possibility that the severity of the Late Devonian extinction stems from the simultaneous or sequential effects of independent factors. www.americanscientist.org /template/BookReviewTypeDetail/assetid/28695   (992 words)

Devonian Times - More about Ferns However, their diverse fossil record extends from the Late Devonian and includes some large arborescent forms (e.g., Calamites/Annularia) that were abundant in the Late Carboniferous swamp forests. A third wave of leptosporangiate diversification occurred during the Late Cretaceous/early Tertiary, and was dominated by a group known as the polypod ferns (e.g., Asplenium, Blechnum, Pteris, Pteridium). The Stauropteridales (e.g., Gillespeia and Stauropteris) extend from the Late Devonian to the Late Carboniferous. www.devoniantimes.org /who/pages/ferns.html   (1914 words)

Chapter 11 Study Guide Another significant radiation occurred throughout the Early-Middle Devonian with the evolution of fish with jaws, a mollusc group termed the ammonoids, and insects. The Late Devonian is characterized by a widespread extinction. The Late Devonian records the evolution of amphibians and resulting radiation of vertebrate organisms onto land. www.uvm.edu /~cmehrten/courses/historical/ch14sg.html   (806 words)

ENDEMISM AND DIVERSIFICATION OF MIDDLE AND LATE DEVONIAN RHOMBIFERANS   (Site not responding. Last check: 2007-09-08) An initial rapid diversification resulted in a global distribution by the Middle Ordovician, which was retained until the clade experienced a dramatic decrease in diversity by the end of the Early Devonian. By the Middle to Late Devonian (Givetian to Frasnian) only Callocystitids remained, and even these appear to be geographically restricted to shallow-water, mixed carbonate-clastic facies of the North American mid-continent in present day Iowa, Michigan and Missouri. In the Middle to Late Devonian, Strobilocystites evolved branching ambulacra with upwards of 250 short, thin brachioles, although brachiole size retained the primitive condition. gsa.confex.com /gsa/2001AM/finalprogram/abstract_26028.htm   (427 words)

Late Devonian to Permian The Late Devonian experienced a mass extinction in marine animals. The Late Devonian extinction was one of five Phanerozoic mass extinctions. The dominant reptiles of the late Carboniferous and Permian are synapsid or so-called “mammal-like” reptiles that would eventually lead to mammals. www.priweb.org /ed/ICTHOL/THOLlecnotes/THOLcbtopm.htm   (1880 words)

Fossil Record of the Seed Plants This large and important group appeared early in the evolution of vascular plants, and throughout the Late Paleozoic shared dominance of the land flora with ferns, lycophytes, and sphenopsids. The earliest seeds appear in the Late Devonian. In modern cycads and conifers, this chamber exudes sticky fluids to aid in pollen capture, and as the fluid dries, it pulls the pollen inside the micropyle. www.ucmp.berkeley.edu /seedplants/seedplantsfr.html   (703 words)

NEW STYGINIDS FROM THE LATE DEVONIAN OF WESTERN AUSTRALIA-THE LAST CORYNEXOCHID TRILOBITES Journal of Paleontology - ... WITHIN THE trilobite family Styginidae, the Scutelluinae is a highly diverse subfamily, ranging in age from the Early Ordovician to the Late Devonian. The Late Devonian sedimentary rocks that outcrop along the northern margin of the Canning Basin of Western Australia form one of the best-preserved Paleozoic reef complexes in the world (Playford and Lowry. The first Devonian trilobites recorded from the Canning Basin were specimens collected by Harry P. Woodward, the Western Australian Government Geologist, while on a visit to the Kimberley region of Western Australia in 1906. www.findarticles.com /p/articles/mi_qa3790/is_200609/ai_n16743081   (884 words)

New perspective on the architecture of the Late Devonian arborescent lycopsid Leptophloeum rhombicum (Leptophloeaceae) ... New perspective on the architecture of the Late Devonian arborescent lycopsid Leptophloeum rhombicum (Leptophloeaceae) -- Wang et al. Algeo T. Scheckler J. Maynard 2001 Effects of the Middle to Late Devonian spread of vascular land plants on weathering regimes, marine biotas, and global climate. nov., a slender upright lycopsid from the Late Devonian Cleveland Shale of Ohio. www.amjbot.org /cgi/content/full/92/1/83   (3710 words)

The Devonian   (Site not responding. Last check: 2007-09-08) The Rhynie Chert in Scotland is a Devonian age deposit containing fossils of both Zosterophyllophytes and Trimerophytes, the two major lines of vascular plants. The first tetrapods, or land-living vertebrates, appeared during the Devonian, as did the first terrestrial arthropods, including wingless insects and the earliest arachnids. The Devonian Period is part of the Paleozoic Era. www.ucmp.berkeley.edu /devonian/devonian.html   (323 words)

Try your search on: Qwika (all wikis)

About us   |   Why use us?   |   Reviews   |   Press   |   Contact us   Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.