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The Cenozoic Portal

Introduction

The Cenozoic (/ˌsiːnəˈzoʊ.ɪk, ˌsɛn-/ SEE-nə-ZOH-ik, SEN-ə-; lit. 'new life') is Earth's current geological era, representing the last 66 million years of Earth's history. It is characterized by the dominance of mammals, birds, conifers, and angiosperms (flowering plants). It is the latest of three geological eras of the Phanerozoic Eon, preceded by the Mesozoic and Paleozoic. The Cenozoic started with the Cretaceous–Paleogene extinction event, when many species, including the non-avian dinosaurs, became extinct in an event attributed by most experts to the impact of a large asteroid or other celestial body, the Chicxulub impactor.

The Cenozoic is also known as the Age of Mammals because the terrestrial animals that dominated both hemispheres were mammals – the eutherians (placentals) in the Northern Hemisphere and the metatherians (marsupials, now mainly restricted to Australia and to some extent South America) in the Southern Hemisphere. The extinction of many groups allowed mammals and birds to greatly diversify so that large mammals and birds dominated life on Earth. The continents also moved into their current positions during this era.

The climate during the early Cenozoic was warmer than today, particularly during the Paleocene–Eocene Thermal Maximum. However, the Eocene to Oligocene transition and the Quaternary glaciation dried and cooled Earth. (Full article...)

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Selected article on the Cenozoic world and its legacies

Calabozos is a Holocene caldera in central Chile's Maule Region (7th Region). Part of the Chilean Andes' volcanic segment, it is considered a member of the Southern Volcanic Zone (SVZ), one of the three distinct volcanic belts of South America. This most active section of the Andes runs along central Chile's western edge, and includes more than 70 of Chile's stratovolcanoes and volcanic fields. Calabozos lies in an extremely remote area of poorly glaciated mountains.

Calabozos and the majority of the Andean volcanoes formed from the subduction of the oceanic Nazca Plate under the continental South American continental lithosphere. The caldera is in a transitional region between thick and thin lithosphere, and is probably supplied by a pool of andesitic and rhyolitic magma. It sits on a historic bed of volcanic and plutonic sedimentary rock (rock formed within the Earth) that in turn sits on top of a layer of merged sedimentary and metamorphic rock.

Calabozos is responsible for the huge Loma Seca Tuff, a body of material 200 cubic kilometres (48 cu mi) to 500 cubic kilometres (120 cu mi) in volume. It accumulated over at least three eruptive periods, beginning 800,000 years ago (0.8 mya) and lasting until 150,000 years ago (0.15 mya).

The caldera's dimensions are 26 kilometres (16 mi) by 14 kilometres (8.7 mi), and it has an elevation of 3,508 metres (11,509 ft). Activity from the caldera has produced many other stratovolcanoes to form a complex volcano. (Full article...)

Selected article on the Cenozoic in human science, culture and economics

The Bone Wars, also known as the Great Dinosaur Rush, was a period of intense and ruthlessly competitive fossil hunting and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope (of the Academy of Natural Sciences of Philadelphia) and Othniel Charles Marsh (of the Peabody Museum of Natural History at Yale). Each of the two paleontologists used underhanded methods to try to outdo the other in the field, resorting to bribery, theft, and the destruction of bones. Each scientist also sought to ruin his rival's reputation and cut off his funding, using attacks in scientific publications.

Their search for fossils led them west to rich bone beds in Colorado, Nebraska, and Wyoming. From 1877 to 1892, both paleontologists used their wealth and influence to finance their own expeditions and to procure services and dinosaur bones from fossil hunters. By the end of the Bone Wars, both men had exhausted their funds in the pursuit of paleontological supremacy.

Cope and Marsh were financially and socially ruined by their attempts to outcompete and disgrace each other, but they made important contributions to science and the field of paleontology and provided substantial material for further work—both scientists left behind many unopened boxes of fossils after their deaths. The efforts of the two men led to 136 new species of dinosaurs being discovered and described. The products of the Bone Wars resulted in an increase in knowledge of prehistoric life, and sparked the public's interest in dinosaurs, leading to continued fossil excavation in North America in the decades to follow. Many historical books and fictional adaptations have been published about this period of intense fossil-hunting activity. (Full article...)

Selected images

Image 1Fossil tooth of Hyainailurus, an extinct genus of hyaenodont mammal of the family Hyainailouridae that lived during the Miocene
Image 2Indarctos is a genus of mammals of the bear family, Ursidae, endemic to North America, Europe and Asia during the Miocene
Image 3Morotopithecus bishopi is a species of fossil ape discovered in Miocene-age deposits of Moroto, Uganda.
Image 4Adcrocuta is an extinct genus of terrestrial carnivore in the family Hyaenidae that lived during the Miocene period
Image 5Palaeotragus ("ancient goat") is a genus of very large, primitive, okapi-like giraffid from the Miocene of Africa, Eurasia.
Image 6Mimoperadectes is an extinct genus of didelphimorph marsupial from the Eocene of North America
Image 7Platybelodon ("flat-spear tusk") was a genus of large herbivorous mammals related to the elephant (order Proboscidea). It lived during the late Miocene Epoch in Asia and the Caucasus.
Image 8Proconsul is an extinct genus of primates that existed from 23 to 25 million years ago during the Miocene epoch
Image 9Prolibytherium ("Before Libya's Beast") is an extinct climacoceratid artiodactyl ungulate native to Early Miocene North Africa and Pakistan
Image 10Deinotherium was a large prehistoric relative of modern-day elephants that appeared in the Middle Miocene and survived until the Early Pleistocene
Image 11Stegotetrabelodon is an extinct genus of primitive elephant with gomphothere-like anatomical features from the Late Miocene to Early Pliocene of Africa and Eurasia
Image 12Victoriapithecus macinnesi was a primate from middle Miocene central Africa