The Orosirian (IPA: /ˌɒroʊˈsɪəriən/, Greek: orosira, meaning "mountain range") is the third geologic period in the Paleoproterozoic Era and lasted from 2050 Ma to 1800 Ma (million years ago). Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit The Paleoproterozoic (ˌpeɪlɪoʊˌproʊtərəˈzoʊɪk also spelled Palaeoproterozoic) is the first of the three sub-divisions ( eras) of the Annum is one form of the Latin noun meaning Year, not a form normally used for derivatives in modern languages the accusative singular Instead of being based on stratigraphy, these dates are defined chronometrically. Stratigraphy, a branch of Geology, studies rock layers and layering ( stratification)

Latter half of the period was an episode of intensive orogeny on virtually all continents. Orogeny (Greek for "mountain generating" is the process of natural Mountain building and may be studied as a tectonic structural event as a geographical event and A continent is one of several large Landmasses on Earth. They are generally identified by Convention rather than any strict criteria with seven regions

Probably during this period Earth's atmosphere changed to oxygen-rich due to photosynthesis of cyanobacteria. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy

Two of the largest known impact events on Earth occurred during the Orosirian. See also Impact crater An impact event is the Collision of a large Meteoroid, Asteroid or Comet (generically At the very beginning of the period, 2023 Ma, a large asteroid collision created the Vredefort impact structure. Asteroids, sometimes called Minor planets or planetoids', are bodies—primarily of the inner Solar System —that are smaller than planets but Vredefort crater is the largest verified Impact crater on Earth. The event that created the Sudbury Basin structure occurred near the end of the period, 1850 Ma. The Sudbury Basin, also known as Sudbury Structure or the Sudbury Nickel Irruptive, is the second largest known Impact crater or Astrobleme

References

• Orosirian Period. GeoWhen Database. Retrieved on January 5, 2006.
• James G. Ogg (2004). "Status on Divisions of the International Geologic Time Scale.". Lethaia 37: 183–199. doi:10.1080/00241160410006492. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  

Proterozoic eon
Paleoproterozoic era				Mesoproterozoic era			Neoproterozoic era
Siderian	Rhyacian	Orosirian	Statherian	Calymmian	Ectasian	Stenian	Tonian	Cryogenian	Ediacaran

The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth. The Paleoproterozoic (ˌpeɪlɪoʊˌproʊtərəˈzoʊɪk also spelled Palaeoproterozoic) is the first of the three sub-divisions ( eras) of the The Mesoproterozoic Era is a geologic era that occurred between 1600 Ma and 1000 Ma (million years ago The Neoproterozoic Era is the unit of geologic time from 1000 to 542 +/- 0 The Siderian (saɪˈdɪəriən sideros meaning "iron" is the first Geologic period in the Paleoproterozoic Era and lasted from 2500 The Rhyacian (raɪˈeɪsiən Ρυαξ ( rhyax) meaning "stream of Lava " is the second Geologic period in the Paleoproterozoic The Statherian (stəˈθɪəriən statheros, meaning "stable firm" is the final Geologic period in the Paleoproterozoic Era The Calymmian (from Greek calymma, "cover" is the first Geologic period in the Mesoproterozoic Era and lasted The Ectasian (from Greek ectasis, "extension" is the second Geologic period in the Mesoproterozoic era and lasted The Stenian (from Greek stenos, "narrow" is the final Geologic period in the Mesoproterozoic Era and lasted The Tonian (from Greek tonas, "stretch" is the first Geologic period in the Neoproterozoic Era and lasted from The Cryogenian (from Greek cryos "cold" and genesis "birth" is a Geologic period that lasted from. The Ediacaran Period (ˌiːdiˈækərən named after the Ediacara Hills of South Australia) is the last geological period of the Neoproterozoic

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