OrdovicianThe Ordovician ( or-də-VISH-ee-ən, -doh-, -VISH-ən) is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon. The Ordovician spans 43.75 million years from the end of the Cambrian Period 486.85 Ma (million years ago) to the start of the Silurian Period 443.1 Ma.
Iapetus OceanThe Iapetus Ocean (; ) existed in the late Neoproterozoic and early Paleozoiceras of the geologic timescale (between 600 and 425 million years ago). It was in the Southern Hemisphere, between the paleocontinents of Laurentia, Baltica and Avalonia. The ocean disappeared with the Acadian, Caledonian and Taconicorogenies, when these three continents joined to form one big landmass called Euramerica.
GondwanaGondwana ( ; Sanskrit:) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian subcontinent.
Geologic time scaleSystem that relates geologic strata to timeThe geologic time scale, proportionally represented as a log-spiral with some major events in Earth's history. A megaannum (Ma) represents one million (10) years.The geologic time scale or geological time scale describes how geologic time is divided into standardised intervals.PaleozoicThe Paleozoic ( PAL-ee-ə-ZOH-ik, -ee-oh-, PAY-; or Palaeozoic) Era is the first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.902 Ma at the start of the Mesozoic Era. The Paleozoic is subdivided into six geologic periods, (from oldest to youngest) Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
LaurentiaLaurentia or the North American craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and the Hebridean terrane in northwest Scotland.
Convergent boundaryA convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a plane where many earthquakes occur, called the Wadati–Benioff zone.
EdiacaranEvents of the Ediacaran PeriodVertical axis scale: millions of years agoEtymologyName formalityFormalName ratified1990Usage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitPeriodStratigraphic unitSystemTime span formalityFormalLower boundary definitionWorldwide distinct cap carbonates.Beginning of a distinctive pattern of secular changes in carbon isotopes.Lower boundary GSSPEnorama Creek section, Flinders Ranges, South Australia31°19′53″S138°38′00″E / 31.3314°S 138.6334°E / -31.3314; 138.6334Lower GSSP ratifiedMarch 12, 2004Upper boundary definitionAppearance of the IchnofossilTreptichnus pedumUpper boundary GSSPFortune Head section, Newfoundland, Canada47°04′34″N55°49′52″W / 47.0762°N 55.8310°W / 47.0762; -55.8310Upper GSSP ratifiedAugust 1992 (as base of Cambrian)Atmospheric and climatic dataMean atmospheric O2 contentc.
PanthalassaIn historical geology, Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean (from Ancient Greek πᾶν (pan) 'all' and θάλασσα (thalassa) 'sea'), was the vast superocean that encompassed planet Earth and surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth.
Volcanic arcA volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc located further from the subducting plate than the trench. The oceanic plate is saturated with water, mostly in the form of hydrous minerals such as micas, amphiboles, and serpentines.
LifeLife is the capacity in matter, formed of one or more units called cells, for processes such as cell signaling, homeostasis, metabolism, cell growth, adaptation, response to stimuli, and reproduction. All life eventually reaches a state of death. Many philosophical definitions of living systems have been proposed, such as self-organizing systems.
PhanerozoicThe Phanerozoic is the current and the latest of the four geologic eons in the Earth's geologic time scale, covering the time period from 538.8 ± 0.6 million years ago to the present. It is the eon during which abundant animal and plant life has proliferated, diversified and colonised various niches on the Earth's surface, beginning with the Cambrian period when animals first developed hard shells that can be clearly preserved in the fossil record.*As an Amazon Associate I earn from qualifying purchases.