Search results
Results From The WOW.Com Content Network
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 cause for the end of the Late Ordovician Glaciation is a matter of intense research, but evidence shows that the deglaciation in the terminal Hirnantian may have occurred abruptly, as Silurian strata marks a significant change from the glacial deposits left during the Late Ordovician. [66]
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 ...
Unknown; may include climate changes, massive volcanic eruptions and Humans (largely by human overhunting) [4] [5] [6] Neogene: Pliocene–Pleistocene boundary extinction: 2 Ma: Possible causes include a supernova [7] [8] or the Eltanin impact [9] [10] Middle Miocene disruption: 14.5 Ma Climate change due to change of ocean circulation patterns.
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 ...
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.
Scientists are using a UC Santa Cruz greenhouse to recreate the mass extinction that wiped out the dinosaurs. They want to learn why some species survived when so many did not.