The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding age.
When the Early Cretaceous Period began 144 million years ago, the huge land mass known as Pangaea had already started to separate. Laurasia (present-day North America, Europe, and Asia) was almost completely separated from Gondwanaland (present-day South America, Africa, India, Antarctica, and Australia).
The Eocene ( / ˈ iː ə ˌ s iː n, ˈ iː oʊ-/) Epoch, lasting from , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch.
The Huronian glaciation (or Makganyene glaciation) was a glaciation that extended from 2.4 billion years ago (Ga) to 2.1 Ga, during the Siderian and Rhyacian periods of the Paleoproterozoic era. The Huronian glaciation followed the Great Oxygenation Event (GOE), a time when increased atmospheric oxygen decreased atmospheric methane. The oxygen combined with the methane to form carbon dioxide and water, which do not retain heat as well as methane does.
The Late Jurassic is the third epoch of the Jurassic period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago, which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "malm" indicates rocks of Late Jurassic age. In the past, this name was also used to indicate the unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units.
The Late Triassic is the third and final of three epochs of the Triassic Period in the geologic timescale. The Triassic-Jurassic extinction event began during this epoch and is one of the five major mass extinction events of the Earth. The corresponding series is known as the Upper Triassic.
The Mesozoic was a time of significant tectonic, climate and evolutionary activity. The era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between warming and cooling periods.
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between 247.2 Ma and 237 Ma (million years ago). The Middle Triassic is divided into the Anisian and Ladinian ages or stages.
The Mississippian culture was a mound-building Native American civilization archeologists date from approximately 800 CE to 1600 CE, varying regionally. It was composed of a series of urban settlements and satellite villages (suburbs) linked together by a loose trading network, the largest city being Cahokia, believed to be a major religious center.
Paleoproterozoic Era, spanning the time period from 2,500 to 1,600 million years ago, is the first of the three sub-divisions of the Proterozoic Eon. It was during this era that the continents first stabilized. Paleontological evidence suggests that the Earth's rotational rate during this era resulted in 20 hour days ~1.8 billion years ago, implying a total of ~450 days per year.
Pennsylvania is the 33rd-largest state by area, and the 6th-most populous state according to the last official US census count in 2010. It is the 9th-most densely populated of the 50 states. Pennsylvania's two most populous cities are Philadelphia (1,567,872), and Pittsburgh (303,625).
The Phanerozoic Eon is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. It covers 541 million years to the present, and began with the Cambrian Period when diverse hard-shelled animals first appeared.
Teasing out the history of the Pliocene is a little like digging through a family’s past. One group of enthusiasts goes through genealogical records, collecting data on who lived where, and when. Another group uses computer software and modeling to look for broad patterns that describe how the family grew and moved over time.
The period of Earth's history that began 2.5 billion years ago and ended 542.0 million years ago is known as the Proterozoic, which is subdivided into three eras: the Paleoproterozoic (2.5 to 1.6 billion years ago), Mesoproterozoic (1.6 to 1 billion years ago), and Neoproterozoic (1 billion to 542.0 ...
Turonian 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.
The Ypresian shares its name with the Belgian Ieper Group (French: Groupe d'Ypres), which has an Ypresian age. The base of the Ypresian stage is defined at a strong negative anomaly in δ 13 C values at the PETM. The official reference profile for the base of the Ypresian is the Dababiya profile near the Egyptian city of Luxor.