Search results
Results from the WOW.Com Content Network
The geologic time scale, proportionally represented as a log-spiral with some major events in Earth's history. A megaannus (Ma) represents one million (10 6) years.. The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth.
Earth of the early Archean may have had a different tectonic style. It is widely believed that the early Earth was dominated by vertical tectonic processes, such as stagnant lid, [19] [20] heat-pipe, [21] or sagduction, [22] [23] [24] which eventually transitioned to plate tectonics during the planet's mid-stage evolution. However, an ...
This is a list of such named time periods as defined in various fields of study. ... Geologic Time – Period prior to humans. 4.6 billion to 3 million years ago ...
The first eon in Earth's history, the Hadean, begins with Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of Earth's crust and Earth itself.
The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [11] End Ordovician: 440 million years ago, 86% of all species lost, including graptolites
Basin Groups Era begins on Earth. c. 4,450 Ma – 100 million years after the Moon formed, the first lunar crust, formed of lunar anorthosite, differentiates from lower magmas. The earliest Earth crust probably forms similarly out of similar material. On Earth the pluvial period starts, in which the Earth's crust cools enough to let oceans form.
era Archean ICS Plumb, 1991 Mesoproterozoic: 1,600 1,000 era ICS Hofmann, 1987 Mesozoic: 251.0 ± 0.7 65.5 ± 0.3 era ICS middle life: Philips, 1818 Messinian: 7.246 5.332 age Miocene ICS Messina (Italy) Mayer-Eymar, 1867 Miaogoalingian: 422 418.7 age Silurian China Miaolingian: 509 497 Epoch Cambrian ICS Migneintian: 486 478.6 ± 1.7 age ...
See calendar and list of calendars for other groupings of years. See history, history by period, and periodization for different organizations of historical events. For earlier time periods, see Timeline of the Big Bang, Geologic time scale, Timeline of evolution, and Logarithmic timeline.