Definition, Betydelse & Synonymer | Engelska ordet SILURIAN

Definition av SILURIAN

1. (geokronologi) silur
2. (geokronologi) silurisk

Exempel på hur man kan använda SILURIAN i en mening

• The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in North Wales in the Cambrian and Silurian systems, respectively.
• Some geological timescales divide the Paleozoic informally into early and late sub-eras: the Early Paleozoic consisting of the Cambrian, Ordovician and Silurian; the Late Paleozoic consisting of the Devonian, Carboniferous and Permian.
• The Silurian is the third and shortest period of the Paleozoic Era, and the third of twelve periods of the Phanerozoic Eon.
• The Devonian Period rocks are more common than Silurian Period rocks, making up two thirds of the county.
• The county lies over 16 different rock formations (which are from the Ordovician, Silurian, and Devonian) and 51 different soils.
• As part of the Driftless Area, the county was ice free during the last ice age, and as one progresses to the Mississippi River, the streams and rivers display high-walled canyons carved of Silurian period bedrock.
• As a result, bedrock found in the area now bounded as Boone County is almost entirely Ordovician, as opposed to nearby counties like McHenry and Carroll which contain large areas of later Silurian bedrock.
• Rosendale natural cement was produced from dolomite extracted from mines in the Rosendale and Whiteport members of the Late Silurian Rondout Formation.
• The Silurian Tuscarora Formation, a hard sandstone, outcrops at the crests of the ridges and is stratigraphically higher and thus younger than the rest of the bedrock in the valley.
• The Silurian Tuscarora Formation, a hard sandstone, outcrops at the crests of the ridges and is stratigraphically higher and thus younger than the rest of the bedrock in the valley.
• It is composed of an outcrop belt of the Lockport Formation of Silurian age, and is similar to the Onondaga Formation, which runs in a parallel outcrop belt just to the south, through western New York and southern Ontario.
• It is also a rare example in Europe of an outcrop representing three geological time periods (the Silurian, the Devonian and the Upper Carboniferous).
• The area has some subterranean Silurian limestone formations that are part of the Racine Dolomite that stretches through eastern Wisconsin and Illinois.
• The southern part of Germantown is rich in Silurian limestone, which was quarried beginning in the 1870s, particularly in the Rockfield and South Germantown areas.
• The southern part of Germantown is rich in Silurian limestone, which was quarried beginning in the 1870s, particularly in the Rockfield and South Germantown areas.
• The earliest known fossil vertebrates were heavily armored fish discovered in rocks from the Ordovician period about 485 to 444 Ma (megaannum, million years ago), with jawed vertebrates emerging in the following Silurian period (444 to 419 Ma) with the placoderms and acanthodians.
• Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Ordovician Soom Shale, the Silurian Waukesha Biota, the Devonian Hunsrück Slates and Gogo Formation, the Carboniferous Mazon Creek, the Triassic Madygen Formation, the Jurassic Posidonia Shale and Solnhofen Limestone, the Cretaceous Yixian, Santana, & Agua Nueva formations and the Tanis Fossil Site, the Eocene Fur Formation, Green River Formation, Messel Formation & Monte Bolca, the Miocene Foulden Maar and Ashfall Fossil Beds, the Pliocene Gray Fossil Site, and the Pleistocene Naracoorte Caves & La Brea Tar Pits.
• The Silures proved among the most intractable of Rome's opponents, Tacitus described them as "exceptionally stubborn" and Raymond Howell, in his county history published in 1988, notes that while it took the Romans five years to subdue south-east England, it took thirty-five before complete subjugation of the Silurian territories was achieved.
• The limestone country rock is intruded by a handful of NE-SW aligned lamprophyre dykes of Silurian to early Devonian age associated with the Strontian Granite Complex and by large numbers of NW-SE aligned dykes of dolerite and basalt of Palaeogene age along with a rather fewer number assigned to the ‘Loch Scridain Suite.
• The bedrock of the island consists of Silurian and Devonian sedimentary rocks, primarily metamorphosed, highly cemented quartzite conglomerate-breccias, with subordinate conglomerate, sandstone and clay, which form cliffs surrounding the island up to 25 metres high.

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