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An illustration depicting Cameroceras shells sticking out of the mud as a result of draining seaways during the Ordovician-Silurian Extinction event. The cause of the glaciation is heavily debated. The late Ordovician glaciation was preceded by a fall in atmospheric carbon dioxide (from 7,000 ppm to 4,400 ppm).
The Llandoverian Epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up of ecosystems. Widespread reef building started in this period and continued into the Devonian Period when rising water temperatures are thought to have bleached out the coral by killing their photo ...
Most scientists believe that this climatic oscillation caused the major extinction event that took place during this time. In fact, the Hirnantian (also known as the End Ordovician and the Ordovician-Silurian) mass extinction event represents the second largest such event in geologic history. Approximately 85% of marine (sea-dwelling) species died.
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 ...
The Silurian period has been viewed by some palaeontologists as an extended recovery interval following the Late Ordovician mass extinction (LOME), which interrupted the cascading increase in biodiversity that had continuously gone on throughout the Cambrian and most of the Ordovician. [36] The Silurian was the first period to see megafossils ...
The Ordovician–Silurian extinction events may have been caused by an ice age that occurred at the end of the Ordovician Period, due to the expansion of the first terrestrial plants, [54] as the end of the Late Ordovician was one of the coldest times in the last 600 million years of Earth's history.
Researchers have gone back in time to find an extinction event that predates all other known events of their kind. Scientists Discovered a Surprise 6th Mass Extinction, Which Came Before the Big 5 ...
It has been suggested that anoxic events caused or contributed to the Ordovician–Silurian, [170] [171] [172] late Devonian, [173] [174] [175] Capitanian, [176] [177] [178] Permian–Triassic, [179] [180] [181] and Triassic–Jurassic extinctions, [182] as well as a number of lesser extinctions (such as the Ireviken, Lundgreni, Mulde, Lau ...