First era of the Proterozoic Eon
Paleoproterozoic
−2500 —
–
−2400 —
–
−2300 —
–
−2200 —
–
−2100 —
–
−2000 —
–
−1900 —
–
−1800 —
–
−1700 —
–
−1600 —
–
An approximate timescale of key Paleoproterozoic events. Axis scale: millions of years ago.
Proposed redefinition(s) 2420–1780 Ma
Gradstein et al., 2012 Proposed subdivisions Oxygenian Period, 2420–2250 Ma
Gradstein et al., 2012
Jatulian/Eukaryian Period, 2250–2060 Ma
Gradstein et al., 2012
Columbian Period, 2060–1780 Ma
Gradstein et al., 2012 Name formality Formal Alternate spelling(s) Palaeoproterozoic Celestial body
Earth Regional usage Global (
ICS ) Time scale(s) used ICS Time Scale Chronological unit
Era Stratigraphic unit
Erathem Time span formality Formal Lower boundary definition Defined Chronometrically Lower GSSA ratified 1991
[1] Upper boundary definition Defined Chronometrically Upper GSSA ratified 1991
[1]
The Paleoproterozoic Era
[4] (also spelled Palaeoproterozoic ) is the first of the three sub-divisions (
eras ) of the
Proterozoic
eon , and also the longest era of the Earth's
geological history , spanning from
2,500 to 1,600 million years ago (2.5–1.6
Ga ). It is further subdivided into four
geologic periods , namely the
Siderian ,
Rhyacian ,
Orosirian and
Statherian .
Paleontological evidence suggests that the Earth's rotational rate ~1.8 billion years ago equated to 20-hour days, implying a total of ~450 days per year.
[5] It was during this era that the
continents first stabilized.[
clarification needed ]
Atmosphere
The
Earth's atmosphere were originally a weakly
reducing atmosphere consisting largely of
nitrogen ,
methane ,
ammonia ,
carbon dioxide and
inert gases ,
[6] somewhat comparable to
Titan's atmosphere .
[7] When
oxygenic photosynthesis evolved in
cyanobacteria during the
Mesoarchean , the increasing amount of
byproduct
dioxygen began to deplete the
reductants in the
ocean ,
land surface and the atmosphere. Eventually all surface reductants (particularly
ferrous iron ,
sulfur and
atmospheric methane ) were exhausted, and the atmospheric
free oxygen levels soared permanently during the Siderian and Rhyacian periods in an
aerochemical event called the
Great Oxidation Event , which brought atmospheric oxygen from near none to up to 10% of the modern level.
[8]
Emergence of eukaryotes and complex life
At the beginning of the preceding
Archean eon, almost all existing lifeforms were
single-cell
prokaryotic
anaerobic organisms whose
metabolism was based on a form of
cellular respiration that did not require oxygen, and
autotrophs were either
chemosynthetic or relied upon
anoxygenic photosynthesis . After the Great Oxygenation Event, the then mainly
archaea -dominated anaerobic
microbial mats were devastated as free oxygen is highly reactive and biologically toxic to cellular structures. This was compounded by a 300-
million-year -long
global icehouse event known as the
Huronian glaciation — at least partly due to the depletion of atmospheric methane, a powerful
greenhouse gas — resulted in what is widely considered one of the first and most significant
mass extinctions on Earth.
[9]
[10] The organisms that thrived after the extinction were mainly
aerobes that evolved
bioactive antioxidants and eventually
aerobic respiration , and surviving anaerobes were forced to live
symbiotically alongside aerobes in hybrid colonies, which enabled the evolution of
mitochondria in
eukaryotic organisms .
Many crown node eukaryotes (from which the modern-day eukaryotic lineages would have arisen) have been approximately dated to around the time of the Paleoproterozoic Era.
[11]
[12]
[13]
While there is some debate as to the exact time at which eukaryotes evolved,
[14]
[15]
current understanding places it somewhere in this era.
[16]
[17]
[18] Statherian
fossils from the
Changcheng Group in
North China provide evidence that eukaryotic life was already diverse by the late Palaeoproterozoic.
[19]
Geological events
During this era, the earliest global-scale continent-continent collision belts developed. The associated continent and mountain building events are represented by the 2.1–2.0 Ga Trans-Amazonian and
Eburnean
orogens in South America and West Africa; the ~2.0 Ga
Limpopo Belt in southern Africa; the 1.9–1.8 Ga
Trans-Hudson ,
Penokean , Taltson–Thelon,
Wopmay ,
Ungava and
Torngat orogens in North America, the 1.9–1.8 Ga
Nagssugtoqidian Orogen in Greenland; the 1.9–1.8 Ga Kola–Karelia,
Svecofennian , Volhyn-Central Russian, and Pachelma orogens in Baltica (Eastern Europe); the 1.9–1.8 Ga
Akitkan Orogen in Siberia; the ~1.95 Ga Khondalite Belt; the ~1.85 Ga Trans-North China Orogen in North China; and the 1.8-1.6 Ga
Yavapai and
Mazatzal orogenies in southern North America.
That pattern of collision belts supports the formation of a Proterozoic supercontinent named
Columbia or
Nuna .
[20]
[21] That continental collisions suddenly led to mountain building at large scale is interpreted as having resulted from increased biomass and carbon burial during and after the Great Oxidation Event: Subducted carbonaceous sediments are hypothesized to have lubricated compressive deformation and led to crustal thickening.
[22]
Felsic volcanism in what is now northern Sweden led to the formation of the
Kiruna and
Arvidsjaur
porphyries .
[23]
The
lithospheric mantle of
Patagonia's oldest blocks formed.
[24]
See also
References
^
a
b Plumb, K. A. (June 1, 1991).
"New Precambrian time scale" . Episodes . 14 (2): 139–140.
doi :
10.18814/epiiugs/1991/v14i2/005 .
^
"palaeo-" .
Lexico UK English Dictionary .
Oxford University Press . Archived from
the original on 2020-06-18.
"Proterozoic" .
Lexico UK English Dictionary .
Oxford University Press . Archived from
the original on 2020-06-17.
^
"Proterozoic" .
Merriam-Webster.com Dictionary .
^ There are several ways of pronouncing Paleoproterozoic , including
PAL -ee-oh-PROH -tər-ə-ZOH -ik, PAY-, -PROT-, -ər-oh-, -trə-, -troh- .
[2]
[3]
^ Pannella, Giorgio (1972). "Paleontological evidence on the Earth's rotational history since early precambrian".
Astrophysics and Space Science . 16 (2): 212.
Bibcode :
1972Ap&SS..16..212P .
doi :
10.1007/BF00642735 .
S2CID
122908383 .
^ Cite error: The named reference Zahnle
was invoked but never defined (see the
help page ).
^ Trainer, Melissa G.; Pavlov, Alexander A.; DeWitt, H. Langley; Jimenez, Jose L.; McKay, Christopher P.; Toon, Owen B.; Tolbert, Margaret A. (2006-11-28).
"Organic haze on Titan and the early Earth" . Proceedings of the National Academy of Sciences . 103 (48): 18035–18042.
doi :
10.1073/pnas.0608561103 .
ISSN
0027-8424 .
PMC
1838702 .
PMID
17101962 .
^ Ossa Ossa, Frantz; Spangenberg, Jorge E.; Bekker, Andrey; König, Stephan; Stüeken, Eva E.; Hofmann, Axel; Poulton, Simon W.; Yierpan, Aierken; Varas-Reus, Maria I.; Eickmann, Benjamin; Andersen, Morten B.; Schoenberg, Ronny (15 September 2022).
"Moderate levels of oxygenation during the late stage of Earth's Great Oxidation Event" .
Earth and Planetary Science Letters . 594 : 117716.
doi :
10.1016/j.epsl.2022.117716 .
hdl :
10481/78482 .
^ Hodgskiss, Malcolm S. W.; Crockford, Peter W.; Peng, Yongbo; Wing, Boswell A.; Horner, Tristan J. (27 August 2019).
"A productivity collapse to end Earth's Great Oxidation" .
Proceedings of the National Academy of Sciences of the United States of America . 116 (35): 17207–17212.
Bibcode :
2019PNAS..11617207H .
doi :
10.1073/pnas.1900325116 .
PMC
6717284 .
PMID
31405980 .
^
Margulis, Lynn ;
Sagan, Dorion (1997-05-29).
Microcosmos: Four Billion Years of Microbial Evolution . University of California Press.
ISBN
9780520210646 .
^ Mänd, Kaarel; Planavsky, Noah J.; Porter, Susannah M.; Robbins, Leslie J.; Wang, Changle; Kraitsmann, Timmu; Paiste, Kärt; Paiste, Päärn; Romashkin, Alexander E.; Deines, Yulia E.; Kirsimäe, Kalle; Lepland, Aivo; Konhauser, Kurt O. (15 April 2022).
"Chromium evidence for protracted oxygenation during the Paleoproterozoic" .
Earth and Planetary Science Letters . 584 : 117501.
doi :
10.1016/j.epsl.2022.117501 .
hdl :
10037/24808 . Retrieved 15 December 2022 .
^ Hedges, S Blair; Chen, Hsiong; Kumar, Sudhir; Wang, Daniel YC; Thompson, Amanda S; Watanabe, Hidemi (2001-09-12).
"A genomic timescale for the origin of eukaryotes" . BMC Evolutionary Biology . 1 : 4.
doi :
10.1186/1471-2148-1-4 .
ISSN
1471-2148 .
PMC
56995 .
PMID
11580860 .
^ Hedges, S Blair; Blair, Jaime E; Venturi, Maria L; Shoe, Jason L (2004-01-28).
"A molecular timescale of eukaryote evolution and the rise of complex multicellular life" . BMC Evolutionary Biology . 4 : 2.
doi :
10.1186/1471-2148-4-2 .
ISSN
1471-2148 .
PMC
341452 .
PMID
15005799 .
^ Rodríguez-Trelles, Francisco; Tarrío, Rosa; Ayala, Francisco J. (2002-06-11).
"A methodological bias toward overestimation of molecular evolutionary time scales" . Proceedings of the National Academy of Sciences of the United States of America . 99 (12): 8112–8115.
Bibcode :
2002PNAS...99.8112R .
doi :
10.1073/pnas.122231299 .
ISSN
0027-8424 .
PMC
123029 .
PMID
12060757 .
^ Stechmann, Alexandra; Cavalier-Smith, Thomas (2002-07-05). "Rooting the eukaryote tree by using a derived gene fusion". Science . 297 (5578): 89–91.
Bibcode :
2002Sci...297...89S .
doi :
10.1126/science.1071196 .
ISSN
1095-9203 .
PMID
12098695 .
S2CID
21064445 .
^ Ayala, Francisco José; Rzhetsky, Andrey; Ayala, Francisco J. (1998-01-20).
"Origin of the metazoan phyla: Molecular clocks confirm paleontological estimates" . Proceedings of the National Academy of Sciences of the United States of America . 95 (2): 606–611.
Bibcode :
1998PNAS...95..606J .
doi :
10.1073/pnas.95.2.606 .
ISSN
0027-8424 .
PMC
18467 .
PMID
9435239 .
^ Wang, D Y; Kumar, S; Hedges, S B (1999-01-22).
"Divergence time estimates for the early history of animal phyla and the origin of plants, animals and fungi" . Proceedings of the Royal Society B: Biological Sciences . 266 (1415): 163–171.
doi :
10.1098/rspb.1999.0617 .
PMC
1689654 .
PMID
10097391 .
^ Javaux, Emmanuelle J.; Lepot, Kevin (January 2018).
"The Paleoproterozoic fossil record: Implications for the evolution of the biosphere during Earth's middle-age" .
Earth-Science Reviews . 176 : 68–86.
doi :
10.1016/j.earscirev.2017.10.001 .
hdl :
20.500.12210/62416 .
^ Miao, Lanyun; Moczydłowska, Małgorzata; Zhu, Shixing; Zhu, Maoyan (February 2019).
"New record of organic-walled, morphologically distinct microfossils from the late Paleoproterozoic Changcheng Group in the Yanshan Range, North China" .
Precambrian Research . 321 : 172–198.
doi :
10.1016/j.precamres.2018.11.019 .
S2CID
134362289 . Retrieved 29 December 2022 .
^ Zhao, Guochun; Cawood, Peter A; Wilde, Simon A; Sun, Min (2002). "Review of global 2.1–1.8 Ga orogens: implications for a pre-Rodinia supercontinent". Earth-Science Reviews . 59 (1–4): 125–162.
Bibcode :
2002ESRv...59..125Z .
doi :
10.1016/S0012-8252(02)00073-9 .
^ Zhao, Guochun; Sun, M.; Wilde, Simon A.; Li, S.Z. (2004).
"A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup" . Earth-Science Reviews . 67 (1–2): 91–123.
Bibcode :
2004ESRv...67...91Z .
doi :
10.1016/j.earscirev.2004.02.003 .
^ John Parnell, Connor Brolly: Increased biomass and carbon burial 2 billion years ago triggered mountain building.
Nature Communications Earth & Environment, 2021,
doi:10.1038/s43247-021-00313-5 (Open Access).
^
Lundqvist, Thomas (2009). Porfyr i Sverige: En geologisk översikt (in Swedish). Sveriges geologiska undersökning. pp. 24–27.
ISBN
978-91-7158-960-6 .
^ Schilling, Manuel Enrique; Carlson, Richard Walter; Tassara, Andrés; Conceição, Rommulo Viveira; Berotto, Gustavo Walter; Vásquez, Manuel; Muñoz, Daniel; Jalowitzki, Tiago; Gervasoni, Fernanda; Morata, Diego (2017). "The origin of Patagonia revealed by Re-Os systematics of mantle xenoliths".
Precambrian Research . 294 : 15–32.
Bibcode :
2017PreR..294...15S .
doi :
10.1016/j.precamres.2017.03.008 .
External links