Search results
Results from the WOW.Com Content Network
The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. [9] Major changes during the Oligocene included a global expansion of grasslands, and a regression of tropical broad leaf forests to the equatorial belt.
Map showing localities of Paraceratherium species during the early (yellow) and late (red) Oligocene, according to Deng and colleagues, 2021. Deng and colleagues speculated about the palaeobiogeography of Paraceratherium based on their phylogenetic analys in 2021.
The formation on United States Geological Survey (USGS) maps is subdivided into four units based on its lithological composition; [5] Tvza - andesitic volcanic rocks (early Miocene? to late Oligocene) — Dark-gray to dark reddish-brown andesite and basaltic andesite, hard, very fine-grained matrix with fine- to medium euhedral phenocrysts of ...
The Eocene–Oligocene extinction event, also called the Eocene-Oligocene transition (EOT) or Grande Coupure (French for "great cut"), is the transition between the end of the Eocene and the beginning of the Oligocene, an extinction event and faunal turnover occurring between 33.9 and 33.4 million years ago. [1]
The geologic formation preserves fossils dating back to the Eocene and Oligocene Epochs of the Paleogene Period, during the Cenozoic Era. [4] It contains the most complete Late Eocene − Priabonian and Early Oligocene − Rupelian vertebrate record in North America.
Map of "Europe" in the early Oligocene, some 30 million years ago. The formation of Europe as a coherent landmass dates to after the breakup of Pangaea, taking place during the Oligocene and completed by the early Neogene period, some 20 million years ago.
A brief marine incursion marks the early Oligocene in Europe. There appears to have been a land bridge in the early Oligocene between North America and Europe since the faunas of the two regions are very similar. During the Oligocene, South America was finally detached from Antarctica and drifted north toward North America.
The volcanic clastic Ohanapecosh Formation is an early state of cascade volcanism. It has been dated to the middle Oligocene [36 to 28 Ma]. [1] The strata are as much as 3 kilometres (1.9 miles) thick, with exposures visible in more than 400 square kilometres (99,000 acres) of a total area exceeding 700 square kilometres (170,000 acres).