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The Late Ordovician, also called the Upper Ordovician by geologists, is the third epoch of the Ordovician period.[1]
At this time Western and Central Europe and North America collided to form Laurentia, while glaciers built up in Gondwana, which was positioned over the South Pole. This caused a drop in global temperatures, resulting in "ice house" conditions.[2]
For most of this time life continued to flourish, but at and near the end of the period there were mass-extinction events that seriously affected planktonic forms like conodonts, graptolites, and some groups of trilobites (Agnostida and Pytchopariida, which completely died out, and the Asaphida which were much reduced). Brachiopods, bryozoans and echinoderms were also heavily affected, and the endocerid cephalopods died out completely, except for possible rare Silurian forms. The Ordovician-Silurian Extinction Events may have been caused by an ice age that occurred at the end of the Ordovician period as the end of the Late Ordovician was one of the coldest times in the last 600 million years of earth history.
^Hambrey, M.J. (October 1985). "The late Ordovician—Early Silurian glacial period". Palaeogeography, Palaeoclimatology, Palaeoecology. 51 (1–4): 273–289. doi:10.1016/0031-0182(85)90089-6.
^Buggisch, Werner; Joachimski, Michael M.; Lehnert, Oliver; Bergström, Stig M.; Repetski, John E.; Webers, Gerald F. (2009). "Did intense volcanism trigger the first Late Ordovician icehouse?". Geology. 38 (4): 327–330. doi:10.1130/G30577.1. ISSN 1943-2682.
The LateOrdovician, also called the Upper Ordovician by geologists, is the third epoch of the Ordovician period. At this time Western and Central Europe...
The Ordovician (/ɔːrdəˈvɪʃi.ən, -doʊ-, -ˈvɪʃən/ or-də-VISH-ee-ən, -doh-, -VISH-ən) is a geologic period and system, the second of six periods of the...
Tr–J P–Tr Cap Late D O–S The LateOrdovician mass extinction (LOME), sometimes known as the end-Ordovician mass extinction or the Ordovician-Silurian extinction...
resolution trilobite biostratigraphy for the early late Tremadocian (Tr2) interval (Early Ordovician) Santa Rosita Formation, Argentine Cordillera Oriental"...
Sacabambaspis is an extinct genus of jawless fish that lived in the Ordovician period. Sacabambaspis lived in shallow waters on the continental margins...
instigated, the Great Ordovician Biodiversification Event, although this has been questioned. Geology portal Österplana 065 LateOrdovician impact craters Lockne...
as primitive sharks became more numerous than in the Silurian and LateOrdovician. Tetrapodomorphs, which include the ancestors of all four-limbed vertebrates...
rate in the middle Ordovician-early Silurian, late Carboniferous-Permian, and Jurassic-recent. This argues that the LateOrdovician, end-Permian, and end-Cretaceous...
geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian...
appearing in the Ordovician include: Cyclopyge (Early to LateOrdovician) Selenopeltis (Early to LateOrdovician) Parabolina (Early Ordovician) Cheirurus (Middle...
Productida is an extinct order of brachiopods in the extinct class Strophomenata. Members of Productida first appeared during the Silurian. They represented...
Cambrian Ordovician Silurian Devonian Carboniferous Permian Some geological timescales divide the Paleozoic informally into early and late sub-eras:...
found in northern Manitoba, Canada in 2005; the deposit dates from the LateOrdovician, c. 445 million years ago. The type species, L. aurora, was described...
straight and pointed. It was particularly abundant and widespread in the LateOrdovician, inhabiting the shallow tropical seas in and around Laurentia, Baltica...
during different time intervals of the Early and Middle Ordovician. During the LateOrdovician, diversification slowed down thanks to increased endemism...
interpreted as indicating that the brown algae originated during the Ordovician but their major diversification happened during the Mesozoic, is presented...
and protozoa. They were thought to have appeared as early as the mid-lateOrdovician period as an adaptation of early land plants. Bacterial spores are...
notchpeakensis range. The base of the Tremadocian, the lowest stage of Ordovician, is defined as the first appearance of Iapetognathus fluctivagus at the...
Merostomata is a class of chelicerate arthropods that contains the extinct Eurypterida (sea scorpions) and the extant Xiphosura (horseshoe crabs). The...
taxon of very early, jawless prehistoric fish which lived during the Ordovician period. Arandaspids represent the oldest known craniates, a proposed group...
is an extinct genus of bathyurid trilobites that lived during the LateOrdovician and is known from Canada and the U.S. It may have been a subgenus of...
surface expression of a diatreme that is the northern part of the LateOrdovician Beemerville Alkaline Complex. The surface exposures of the Beemerville...
pp. 451–92. Bond, David P.G.; Grasby, Stephen E. (18 May 2020). "LateOrdovician mass extinction caused by volcanism, warming, and anoxia, not cooling...
as the Junggar Block. Because the Kazakh terranes merged during the LateOrdovician as part of the Central Asian Orogenic Belt they are also referred to...
extant family, Limulidae). They first appeared in the Hirnantian (LateOrdovician). Currently, there are only four living species. Xiphosura contains...
typically coiled tightly within the shell. Spiriferids first appear in the LateOrdovician with the appearance of Eospirifer radiatus. They increased in diversity...
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