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The Cretaceous–Paleogene (K–Pg) extinction event, [ a ] also known as the K–T extinction, [ b ] was the mass extinction of three-quarters of the plant and animal species on Earth [ 2 ][ 3 ] approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than 25 kilograms ...
The Paleogene Period (IPA: / ˈpeɪli.ədʒiːn, - li.oʊ -, ˈpæli -/ PAY-lee-ə-jeen, -lee-oh-, PAL-ee-; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period 66 Ma (million years ago) to the beginning of the Neogene Period 23.03 Ma.
The largest extinction was the Kellwasser Event (Frasnian - Famennian, or F-F, 372 Ma), an extinction event at the end of the Frasnian, about midway through the Late Devonian. This extinction annihilated coral reefs and numerous tropical benthic (seabed-living) animals such as jawless fish, brachiopods, and trilobites.
Chicxulub crater. Chicxulub crater (Mexico) Free-air gravity anomaly over the Chicxulub structure (coastline and state boundaries shown as black lines) The Chicxulub crater (IPA: [t͡ʃikʃuˈluɓ] ⓘ cheek-shoo-LOOB) is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore, but the crater is named after ...
Luis (left) and his son Walter Alvarez (right) at the K-Pg Boundary in Gubbio, Italy, 1981. In 1980, a team of researchers led by Nobel prize-winning physicist Luis Alvarez, his son, geologist Walter Alvarez, and chemists Frank Asaro and Helen Vaughn Michel discovered that sedimentary layers found all over the world at the Cretaceous–Paleogene boundary contain a concentration of iridium ...
Contents. Timeline of Cretaceous–Paleogene extinction event research. Since the 19th century, a significant amount of research has been conducted on the Cretaceous–Paleogene extinction event, the mass extinction that ended the dinosaur -dominated Mesozoic Era and set the stage for the Age of Mammals, or Cenozoic Era.
The climate across the Cretaceous–Paleogene boundary (K–Pg or formerly the K–T boundary) is very important to geologic time as it marks a catastrophic global extinction event. Numerous theories have been proposed as to why this extinction event happened including an asteroid known as the Chicxulub asteroid, volcanism, or sea level changes.
The Alvarez hypothesis posits that the mass extinction of the non-avian dinosaurs and many other living things during the Cretaceous–Paleogene extinction event was caused by the impact of a large asteroid on the Earth. Prior to 2013, it was commonly cited as having happened about 65 million years ago, but Renne and colleagues (2013) gave an ...