The most recent of the Martian geologic epochs, from approximately 1.8 billion (1800 million) years ago (the end of the Hesperian epoch) to the present.
(geology) An age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma), a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series).
Alternative form of Cenozoic [(geology) A geologic era within the Phanerozoic eon comprising the Paleogene, Neogene and Quaternary periods from about 65 million years ago to the present, when the continents moved to their current position and modern plants and animals evolved.]
(evolutionary biology) The relatively rapid appearance, during the Cambrian Period around 541 million years ago, of most major animal phyla, as demonstrated in the fossil record.
(geology) The fifth of six geological ages of the Late Cretaceous epoch, spanning the time from 83.6 ± 0.7 to 72.1 ± 0.6 million years ago. It is preceded by the Santonian and followed by the Maastrichtian.
(geology) The lowermost stage of the Upper Triassic series (or earliest age of the Late Triassic epoch), which lasted from 237 to 227 million years ago and was preceded by the Ladinian and followed by the Norian.
(geology) A geologic era within the Phanerozoic eon comprising the Paleogene, Neogene and Quaternary periods from about 65 million years ago to the present, when the continents moved to their current position and modern plants and animals evolved.
Obsolete form of Cenozoic. [(geology) A geologic era within the Phanerozoic eon comprising the Paleogene, Neogene and Quaternary periods from about 65 million years ago to the present, when the continents moved to their current position and modern plants and animals evolved.]
A geologic era, beginning in the late twentieth century, in which humans would be guided by ecological concerns and would behave in a less exploitative way toward the environment.
(geology) A geochronologic unit of hundreds of thousands to millions of years; a subdivision of a period, and subdivided into ages (or sometimes subepochs).
(geology) The closing subdivision of the Hamilton period in the American Devonian system; so called because the formations of this period crop out in Genesee, New York.
(geology) An age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago).
The second of the three Martian geologic epochs, approximately from 3,500 million years ago to 1,800 million years ago, marked by lava flows, preceded by the Noachian epoch, and followed by the Amazonian epoch.
(geology, paleontology) A geologic age, 53.0–50.0 mya and within the Ypresian (Early Eocene), whose stratotype is the Itaboraí Formation; used especially in the context of South American land mammal age (SALMA) classification.
(geology) Belonging to the sediments of a group of Precambrian rocks more specifically assigned to the Mesoproterozoic Era (Riphean), and including the oldest known sediments in the Baltic area that have not been subject to metamorphism.
(geology, paleontology) The period from 201.3±0.2 to 145 million years ago, after the Triassic and before the Cretaceous; the geologic systems of this period.
The rapid dying off of a large percentage of all animal species in a comparatively short period of time 65.5 million years ago. This coincides with the end of the Cretaceous period, and may have been caused by an impact event.
Alternative form of Carnian [(geology) The lowermost stage of the Upper Triassic series (or earliest age of the Late Triassic epoch), which lasted from 237 to 227 million years ago and was preceded by the Ladinian and followed by the Norian.]
A prolonged event believed to have occurred around the Hadean-Archean boundary, during which an unusually high number of asteroids hit the terrestrial planets and their moons.
(geology) in the ICS geologic timescale, the last stage or age of the Cretaceous period, and of the Mesozoic era, preceded by the Campanian and succeeded by the Danian period.
(evolutionary theory, geology) One of five historical events in which the Earth experienced a loss of ∼75% of all species over a geological interval of less than 3 million years, the most recent being the Cretaceous–Paleogene extinction event 66 million years ago.
Abbreviation of Methodist. [Of or pertaining to the branch of Christianity that descends from the religious societies overseen by John Wesley (1703–1791) among others.]
(geology) A sequence of Upper Jurassic sedimentary rock in the western United States, noted as the most fertile source of dinosaur fossils in North America.
(geology) Of a geologic period within the Cenozoic era; comprises the Miocene, Pliocene, Pleistocene and Holocene epochs from about 26 million years ago to the present.
(geology) Of a geologic era within the Proterozoic eon; comprises the Tonian, Cryogenian and Ediacaran periods from about 1000 to 544 million years ago, when algae and sponges flourished.
(geology) Beds of red sandstone and associated rocks laid down throughout the Permian to the end of the Triassic, underlying the Jurassic-Triassic age Penarth Group.
The earliest of the Martian geologic epochs, approximately from 3,800 million years ago to 3,500 million years ago, marked by many large impact craters and followed by the Hesperian epoch.
Alternative form of Ordovician [(geology) Of a geologic period within the Paleozoic era; comprises lower, middle and upper epochs from about 488 to 443 million years ago.]
(dated) Alternative spelling of Paleoarchean [(geology) Of a geologic era within the Archaean eon from about 3600 to 3200 million years ago; the first aerobic bacteria appeared at this time.]
Alternative form of Paleocene [(geology) A geologic epoch within the Paleogene period from about 65 to 56 million years ago; marked by the rise of the first large mammals in a tropical climate.]
Alternative spelling of Paleozoic [(geology) Of a geologic era within the Phanerozoic eon that comprises the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods from about 542 to 250 million years ago, from the age of trilobites to that of reptiles.]
(geology) A geologic epoch within the Paleogene period from about 65 to 56 million years ago; marked by the rise of the first large mammals in a tropical climate.
(geology) Of a geologic era within the Phanerozoic eon that comprises the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods from about 542 to 250 million years ago, from the age of trilobites to that of reptiles.
Archaic spelling of Paleocene. [(geology) A geologic epoch within the Paleogene period from about 65 to 56 million years ago; marked by the rise of the first large mammals in a tropical climate.]
Archaic spelling of Paleozoic. [(geology) Of a geologic era within the Phanerozoic eon that comprises the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods from about 542 to 250 million years ago, from the age of trilobites to that of reptiles.]
(geology) Pertaining to the last geologic period of the Paleozoic era; comprising the Cisuralian, Guadalupian and Lopingian epochs from about 280 to 248 million years ago.
Alternative form of Pliocene [(geology) Of a geologic epoch within the Neogene period from about 5.3 to 1.7 million years ago; marked by the appearance of humanity's first ancestors.]
(geology) Of a geologic epoch within the Quaternary period from about 2,588,000 to 11,700 years ago (earlier definition 1.7 million to 11,000 years ago); marked by the evolution of man, and the extinction of the large mammals.
(geology) Of a geologic epoch within the Neogene period from about 5.3 to 1.7 million years ago; marked by the appearance of humanity's first ancestors.
Alternative spelling of Precambrian [(geology) The Precambrian supereon; spanning from the formation of the Earth around 4.6 billion years ago to the emergence of hard-shelled creatures 541 million years ago.]
The oceans of the earth at a time early in its history. The term generally implies either the time before or during the development of multi-cellular life forms (i.e., during the Precambrian), or alternatively before the development of the first land-based life forms (i.e. during the early Paleozoic).
(geology) Of a geologic period within the Paleozoic era; comprises the Llandovery, Wenlock, Ludlow and Pridoli epochs from about 439 to 409 million years ago.
(geology) The lowest division of the Carboniferous formations underlying the proper coal measures; a marine formation characterized in general by beds of limestone.
(geology) In the ICS geologic timescale, the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. It lasted from 358.9 Ma to 346.7 Ma and was preceded by the Famennian and followed by the Viséan.
(geology) The second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series, spanning the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma (million years ago), preceded by the Cenomanian stage and underlying the Coniacian stage.
(geology) An obsolete regionally defined geological unit in Russia, in part Jurassic and in part Cretaceous, corresponding to the Tithonian and part of the Berriasian, and perhaps even part of the Kimmeridgian.
(geology) A unit of sedimentary rock layers of Middle to Late Permian age located in the Permian Basin (Europe), corresponding to the Lopingian (epoch).
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