How To Use Ordovician In A Sentence
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The northernmost outcrops consist of Ordovician chloritic slates, phyllitic metavolcanic rocks and slatey metapelitic rocks.
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The Cape Floristic Region overlies the Cape Supergroup, a Devonian-Ordovician series of sedimentary strata, where alternating quartzitic sandstones such as Table Mountain and the Witteberg Groups alternate with fine-grained shales, as seen in the Bokkeveld Group.
Montane fynbos and renosterveld
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It is now widely recognized that the Late Ordovician mass extinction was both coincident with and causally linked to an event of continental glaciation centered in the North African and South American regions of Gondwana.
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This was accompanied by the multistage emplacement of large intrusive bodies in the Cambrian, Ordovician, and Silurian periods.
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Williams, include oceanic crust and mantle rock exposed by the obduction process of plate tectonics, as well as sedimentary rock formed during the Ordovician, Precambrian granite and
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Ordovician strata are characterized by numerous and diverse trilobites and conodonts (phosphatic fossils with a tooth-like appearance) found in sequences of shale, limestone, dolostone, and sandstone.
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Mason is excited because we might find things that were alive in the Ordovician Period ... and, like, he could instantly name three or four creatures alive then.
Day in the Life of an Idiot
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Thick Permian to Cretaceous continental rise deposits merge southward into a continuous Ordovician to Eocene shelf sedimentary succession of marine carbonate, sandstone, siltstone and shale.
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They are generally common microfossils in Phanerozoic marine sedimentary rocks, at least from the early Middle Ordovician onward.
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The new U-Pb analyses on the felsic porphyroids represent the first geochronological demonstration that a magmatic event occurred during the Mid-Ordovician in the Lower Domain of the Peloritan Mountains.
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The Bed G bauxite of Shanxi massif, a paleoresiduum bauxite underlying Bangou Formation of Upper Carboniferous, occurs on the fossil erosion surface of Middle Ordovician of Upper Cambrian.
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The Ordovician is best known for the presence of its diverse marine invertebrates, including graptolites, trilobites, brachiopods, and the conodonts (early vertebrates).
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When bivalves diversified in the Middle to Upper Ordovician, both classes occupied a full range of environments, from nearshore to basinal.
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Recently, it has been proposed as the base of the Upper Ordovician in a formal tripartite subdivision of the system.
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The most remarkable example is the three-dimensionally preserved soft tissues of the giant conodont animal Promissum pulchrum, eurypterids and other arthropods from the Upper Ordovician Soom Shale of South Africa.
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The other one is between the Upper Ordovician Terekawat Formation and the underlying formations, which presents commonly as a parallel unconformity or an angular unconformity in some regions.
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Our geochronology has identified major early Ordovician magmatism within the Slishwood Division.
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That means the rocks are quite a bit older than the Cambrian and Ordovician slate and phyllite at Beavertail, two miles to the southwest.
Of Books and the Sea
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By the end of the Ordovician they had already radiated into many of the niches they occupy today.
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Grey and black mudrocks in the Annascaul Formation have yielded diagnostic palynomorph assemblages indicative of an Early Ordovician age.
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The boundary between the Cambrian and the Ordovician is marked by the appearance of planktic dictyonemid graptolites.
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Here, rocks of the Cambro-Ordovician Conanicut Group, specifically interstratified beds of the Fort Burnside Formation and the older Jamestown Formation form great flat tables of phyllite and siltstone, metamorphosed to varying degrees.
"Don't let the Earth in me subside..."
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The ancient Ordovician wind carried the first land plant spores to barren and empty places, starting the fantastic unfolding of diversity in plant forms, leading to the first flowering plants roughly 140 million years ago and so on to more than 400,000 species today.
Bird Cloud
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These are set against the standard British Ordovician chronostratigraphy of Fortey et aL with the series boundaries calibrated as closely as possible to the chronometric timescale.
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One of the tips yields a concordant analysis with an Ordovician age of 495 Ma.
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The onset of volcanism in the region occurred in late Ordovician times, with the earliest eruptions associated with the Eycott and Borrowdale volcanic groups.
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Some studies that dealt mostly with Upper Cambrian and Lower Ordovician trilobites included descriptions of brachiopods.
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West of the Alpine Fault, the rocks of South Westland consist of a basement of Ordovician greywacke with some high temperature metamorphic rocks and granites, and minor areas of younger Cretaceous and Tertiary sedimentary rocks along the coast.
Te Wahipounamu (South-West New Zealand World Heritage Area), New Zealand
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The late Ordovician had an ice age despite CO2 levels of 4,000 ppm, which is over ten times the current level.
Hansen and Schmidt: Predicting the Past? « Climate Audit
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Remains of ostraderms (jawless, armored fish) from Ordovician rocks comprise some of the oldest vertebrate fossils.
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The late Ordovician brachiopods have been monographed by Villas, who detected a genetic, but not very close, similarity with Armorican and Perunican faunas.
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Minor glaciations may also have taken place in the earlier Ordovician early Silurian and late Devonian.
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The only modern phylum with an adequate fossil record to appear after the Cambrian was the phylum Bryozoa, which is not known before the early Ordovician.
Continuation…
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As expected, both gastropods and bivalves show remarkably similar Ordovician diversity trajectories on a global scale, thus lending support to the synoptic model of global evolutionary faunas.
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The Cape Floristic Region is more-or-less coincident geologically with the Cape Supergroup, a Devonian-Ordovician series of sedimentary strata, consisting of alternating layers of quartzitic sandstones (the Table Mountain and Witteberg Groups) and fine-grained shales (Bokkeveld Group).
Lowland fynbos and renosterveld
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We climbed over the craggy outcrops of Cambro-Ordovician age Fort Burnside Formation and Jamestown Formation, crazily tilted beds of phyllite and slate and siltstone and stark white veins of calcite.
"Into a light that lingers."
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And while jawless vertebrates were present in the Cambrian, it was not until the Ordovician that armored fish became common enough to leave a rich fossil record.
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It is based on the present writers' achievements of study and mapping of quantitative lithofacies palaeogeography of the Cambrian and Ordovician in North China, South China and Northwest China.
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While all of the phyla but one were established during the Cambrian explosion, taxonomic increases during the Ordovician were manifest at lower taxonomic levels although ordinal level diversity doubled.
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My aunt came to Canada for a visit, and she picked up a Middle Ordovician brachiopod fossil off the trail and showed it to me.
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The other one is between the Upper Ordovician Terekawat Formation and the underlying formations, which presents commonly as a parallel unconformity or an angular unconformity in some regions.
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The basement is mainly composed of quartz biotite norite and minor serpentinite which belong to the Ordovician Boganclough intrusion.
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The Cambro-Ordovician boundary is now radiometrically dated at 490 Ma and so only rocks and fossils of late Cambrian age are included in this part of our survey.
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The Ordovician faunas described herein represent both the Midcontinent and Atlantic faunal realms.
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Many crinoids are primarily nocturnal but they are seen during the day with their arms rolled up. living fossil existing virtually unchanged from the ancestors in the geologic age known as the Ordovician Period, but there are many more fossils formed from the Paleozoic Era.
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The Ordovician is best known for the presence of its diverse marine invertebrates, including graptolites, trilobites, brachiopods, and the conodonts (early vertebrates).
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They suggest that fish are very rare in Cambrian and Ordovician rocks because they were active swimmers and could generally escape from the underwater avalanches.
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And while jawless vertebrates were present in the Cambrian, it was not until the Ordovician that armored fish became common enough to leave a rich fossil record.
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It has subsequently been interpreted as a tubiform green alga and as a cyanobacterium, and Ordovician specimens that are evidently Halysis have been referred to the filamentous green alga Oedogonium Link, 1820.
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Cameron found Vermiforichnus clarkei in many substrates from Ordovician to Holocene ages.
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Over this system lie beds which have yielded in succession Ordovician and Silurian fossils, forming altogether a compact division which has been distinguished locally as the _Muth system_.
The Panjab, North-West Frontier Province, and Kashmir
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There, the most widespread Ordovician flysch is the Garin Formation.
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The sequence comprises Lower Ordovician conglomerates and carbonates overlain by Upper Ordovician to Middle Devonian limestone with occasional phyllite and quartzite.
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Ross et al. subdivided the overlying Ordovician Ibexian Series into four stages, the lowest of which is the Skullrockian Stage.
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The ontogeny and dimorphic features of many early Middle Ordovician ostracode species are still poorly known.
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The package also contained a chunk of Ordovician limestone, riddled with the fossil remains of gastropods and brachiopods, from her backyard near Madison, Wisconsin.
"Steampunk happens when goths discover brown."
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This convergence gave rise to southward thrusting of the Yixieke forearc in Ordovician-Early Silurian time, which then led to obduction of the Buziwan ultrabasic rocks southward over the Kudi terrane.
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Remains of ostraderms (jawless, armored fish) from Ordovician rocks comprise some of the oldest vertebrate fossils.
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These rocks are thought to be Ordovician in age based on correlation with fossiliferous rocks at the same structural horizon near Nyalam.
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Enamel, or enameloid tissue covering tubercles, was clearly described in Ordovician vertebrates such as the ostracoderms.
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It constituted part of a Late Ordovician epicontinental fauna that once spread widely in shallow, equatorial seas of North America.
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A systemic and integrated criteria is thus obtained for the Ordovician carbonates in the Tahe oilfield.
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SHRIMP U-Pb dating of recurrent Cryogenian and Late Cambrian-Early Ordovician alkalic magmatism in central Idaho: Implications for Rodinian rift tectonics
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Note that several Cambrian and early Ordovician mass extinctions are not shown here.
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In the course of our investigations into Ordovician lingulate brachiopod faunas from such limestone residues, we have recovered occasional specimens of small ‘hat-like’ phosphatic plates of enigmatic affinities.
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Voluminous quantities of Late Ordovician to Wenlockian felsic pyroclastics and lava flows record the extensive volcanism associated with the collision and deformation.
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Like I said, he knows more about the Ordovician period than I do, so he was quite content to dig a few holes and admire the clam shells and petrified "seaweed" that we found.
Day in the Life of an Idiot
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This fauna and those described previously from older Utah strata document the biodiversification of the Cambrian-Ordovician lingulate brachiopods and demonstrate their potential for regional and intercontinental correlation.
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Structurally associated with an anticline, where erosion of broken rock scooped out the linear valley, it is composed mostly of Mississippian to Ordovician-age limestones, dolomites, and shales, with some low, cherty ridges.
Ecoregions of Alabama and Georgia (EPA)
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Underlain in New Jersey by folded and faulted Ordovician Martinsburg Shale; this slaty shale is slightly more erosion resistant than the limestone underlying Ecoregions 67a and 67j.
Ecoregions of New Jersey (EPA)
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I've been able to determine it came from one of three marines facies, the Galena, Decora, or Platville formations (Middle to Late Ordovician).
"Steampunk happens when goths discover brown."
