Orosirian

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). Instead of being based on stratigraphy, these dates are defined chronometrically.

Latter half of the period was an episode of intensive orogeny on virtually all continents.

Probably during this period Earth's atmosphere changed to oxygen-rich due to photosynthesis of cyanobacteria.

Two of the largest known impact events on Earth occurred during the Orosirian. At the very beginning of the period, 2023 Ma, a large asteroid collision created the Vredefort impact structure. The event that created the Sudbury Basin structure occurred near the end of the period, 1850 Ma.

References

Proterozoic eon
Paleoproterozoic era Mesoproterozoic era Neoproterozoic era
Siderian Rhyacian Orosirian Statherian Calymmian Ectasian Stenian Tonian Cryogenian Ediacaran
This chart shows concisely the most common way in which the International Phonetic Alphabet (IPA) is applied to represent the English language.

See International Phonetic Alphabet for English for a more complete version and Pronunciation respelling for English for phonetic
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Greek}}} 
Writing system: Greek alphabet 
Official status
Official language of:  Greece
 Cyprus
 European Union
recognised as minority language in parts of:
 European Union
 Italy
 Turkey
Regulated by:
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Oceanic crust      0-20 Ma
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A geologic period is a subdivision of geologic time that divides an era into smaller timeframes. The equivalent term used to demarcate rock layers and the fossil record is the system; thus the rocks of the Devonian System were laid down during the Devonian Period.
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The Paleoproterozoic (IPA: /ˌpeɪlɪəʊˌprəʊt(ə)rəˈzəʊɪk/, also spelled Palaeoproterozoic
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A geologic era is a subdivision of geologic time that divides an Eon into smaller buckets. The Phanerozoic Eon is divided into three such timeframes: the Paleozoic, Mesozoic, and Cenozoic represent the major stages in the macroscopic fossil record.
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Annum is a Latin noun meaning year. It is the accusative singular of the second declension masculine noun annus (nominative), anni (genitive) [1] .

As a unit of time, it is defined as exactly 365.
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Stratigraphy, a branch of geology, studies rock layers and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy includes two related subfields: lithologic or lithostratigraphy and biologic stratigraphy or
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Orogeny (Greek for "mountain generating") is the process of mountain building, and may be studied as a tectonic structural event, as a geographical event and a chronological event, in that orogenic events cause distinctive structural phenomena and related tectonic activity,
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continent is one of several large landmasses on Earth. They are generally identified by convention rather than any strict criteria, but seven areas are commonly regarded as continents – they are (from largest in size to smallest): Asia, Africa, North America, South America,
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Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.
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2, −1
(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies
(more) 1st: 1313.9 kJmol−1
2nd: 3388.3 kJmol−1
3rd: 5300.5 kJmol−1

Atomic radius 60 pm
Atomic radius (calc.
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Cyanobacteria

Orders

The taxonomy is currently under revision.[1]

Cyanobacteria (Greek: κυανόs (kyanós) = blue + bacterium) also known as Cyanophyta
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Impact events are caused by the collision of large meteoroids, asteroids or comets (generically: bolides) with Earth and may sometimes be followed by mass extinctions of life. For discussion of impacts in general, not just on Earth, see impact crater.
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Asteroids, also called minor planets or planetoids, are a class of astronomical objects. The term asteroid is generally used to indicate a diverse group of small celestial bodies in the solar system that orbit around the Sun.
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State Party  South Africa
Type Natural
Criteria viii
Reference 1162
Region Africa

Inscription History
Inscription 2005  (29th Session)
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Sudbury Basin, also known as Sudbury Structure, is the second largest known impact crater or astrobleme on Earth, and a major geologic structure in Ontario, Canada.

The basin is located on the Canadian Shield in the city of Greater Sudbury, Ontario.
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January 5 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.

Events

  • 1463 - Poet François Villon is banned from Paris.

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20th century - 21st century - 22nd century
1970s  1980s  1990s  - 2000s -  2010s  2020s  2030s
2003 2004 2005 - 2006 - 2007 2008 2009

2006 by topic:
News by month
Jan - Feb - Mar - Apr - May - Jun
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Proterozoic (IPA: /ˌprəʊt(ə)rəˈzəʊɪk/) is a geological eon representing a period before the first abundant complex life on Earth. The Proterozoic Eon extended from 2500 Ma to 542.
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The Paleoproterozoic (IPA: /ˌpeɪlɪəʊˌprəʊt(ə)rəˈzəʊɪk/, also spelled Palaeoproterozoic
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The Mesoproterozoic Era is a geologic era that occurred between 1600 Ma and 1000 Ma (million years ago).

The major events of this era are the formation of the Rodinia supercontinent, the breakup of the Columbia supercontinent, and the evolution of sexual reproduction.
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The Neoproterozoic Era is the unit of geologic time from 1,000 to 542 +/- 0.3 million years ago.[1] The terminal Era of the formal Proterozoic Eon (or the informal "Precambrian"), it is further subdivided into the Tonian, Cryogenian, and Ediacaran Periods.
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The Siderian (IPA: /saɪˈdɪəriən/, Greek: sideros, meaning "iron") is the first geologic period in the Paleoproterozoic Era and lasted from 2500 Ma to 2300 Ma (million
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The Rhyacian (IPA: /raɪˈeɪsiən/, Greek: Ρυαξ (rhyax)
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The Statherian (IPA: /stəˈθɪəriən/, Greek: statheros
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The Calymmian (from Greek calymma, "cover") is the first geologic period in the Mesoproterozoic Era and lasted from 1600 Ma to 1400 Ma (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically.
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The Ectasian (from Greek ectasis, "extension") is the second geologic period in the Mesoproterozoic era and lasted from 1400 Ma ago to 1200 Ma (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically.
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The Stenian (from Greek stenos, "narrow") is the final geologic period in the Mesoproterozoic Era and lasted from 1200 Ma to 1000 Ma (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically.
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