Pilbara Craton: Difference between revisions

Pilbara Craton
Pilbara Craton
Stratigraphic range: Age Archean Pha. Proterozoic Archean Had.
	Satellite view in 2013 of Pilbara Craton
Type	Geological formation
Area	Estimated 250,000 km2 (97,000 sq mi), Pilbara IRBA v7 region 178,231.26 km2 (68,815.47 sq mi)
Thickness	up to 20 km (12 mi)
Lithology
Primary	Granite
Other	Greenstone
Location
Region	Western Australia
Country	Australia
Type section
Named for	Pilbara
Named by	See Pilbara#Etymology
	; Map of Australia with the Pilbara region highlighted in red.

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KEY

Pilbara Craton subregions:

PIL01 -

Chichester

PIL02 -

Fortescue

PIL03 -

Hamersley

PIL04 -

Roebourne

Carnarvon subregion:

CAR01 -

Cape Range

Gascoyne subregion:

GAS01 -

Ashburton

Pilbara Craton part of the continental lithosphere using version 7 of IBRA classification. The geo-ecosystems of the PIL02(Fortescue) area in particular are usually on much younger exposed rock formations (< 1.7 Ga) than the lithology discussed in this article.

The Pilbara Craton is an old and stable part of the continental lithosphere located in the Pilbara region of Western Australia.

The Pilbara Craton is one of only two pristine Archaean 3.8–2.7 Ga (billion years ago) crusts identified on the Earth, along with the Kaapvaal Craton in South Africa. The youngest rocks are 1.7 Ga old in the historic area assigned to the Craton.^[1] Both locations may have once been part of the Vaalbara supercontinent or the continent of Ur.

There are two subregional geographical classification regimes used, being:

The Interim Biogeographic Regionalisation for Australia based upon interacting geo-ecosystems
Based on geology alone where the eastern continuous oldest portion is called the Eastern Pilbara Craton and younger surface lithologies within the larger craton have different names.

Geology[edit]

The most important part of the Pilbara Craton to understand the early Earth crust is called the Eastern Pilbara Craton, where still exposed today, are crustal rocks that are up to 3.8 billion years old and intrusive granitic domes along with greenstone belts that are about 3.5 to 3.2 billion years old.^[1] The geology was reassessed in 2007 with the separation out from the geologically named Pilbara Craton of a thick succession of interbedded clastic or chemical sedimentary rocks and volcanic rocks forming the Fortescue, Hamersley, and Turee Creek basins that are usually aged from 2.78–2.42 billion years old and the younger volcano-sedimentary Ashburton Basin aged from 2.21–1.79 billion years ago.^[1] A surface region between the Fortescue and Hamersley basins is even younger, at less than 1.7 billion years old, as are the surrounding geo-ecosystems surface rocks to the Pilbara Craton. It is important to note that to the east and south of the Eastern Pilbara Craton there are significant outcrops of the very old rocks and that these are confined to the traditional area of the Pilbara Craton which is inferred to be subsurface for more than half its area.^[1]

Mineralogy[edit]

There are extensive high quality iron ore deposits and also economic to mine gold, silver, copper, nickel, lead, zinc, molybdenum, vanadium and fluorite deposits.^[1]

Evidence of earliest life[edit]

Evidence of the earliest known life on land may have been found in 3.48-billion-year-old geyserite and other related mineral deposits (often found around hot springs and geysers) uncovered in the Dresser Formation in the Pilbara Craton.^[3]^[4]^[5] Biogenic sedimentary structures (microbialites) such as stromatolites and MISS were described from tidal, lagoonal and subtidal coastal settings that can be reconstructed from the Dresser stratigraphy as well.^[6] The rocks of the Dresser Formation display evidence of haematite alteration that may have been microbially influenced.^[7]

The earliest direct evidence of life on Earth may be fossils of microorganisms permineralized in 3.465-billion-year-old Australian Apex chert rocks.^[8]^[9] However, the evidence for the biogenicity of these microstructures has been thoroughly debated.^[10]^[11] Originally, 11 taxa were described from a deposit thought to be located at the mouth of a river due to certain characteristics like rounded and sorted grains.^[12]^[13] Extensive field mapping and petrogenetic analysis has since shown the setting for the purported microfossils to be hydrothermal^[14]^[15] and this is widely supported.^[16]^[17]^[18]^[19] Consequently, many alternative abiotic explanations have been proposed for the filamentous microstructures including carbonaceous rims around quartz spherules and rhombs,^[14]^[15] witherite self-assembled biomorphs^[20] and haematite infilled veinlets.^[21] The carbonaceous matter composing the filaments has also been repeatedly examined with Raman spectroscopy^[14]^[22]^[21] which has yielded mixed interpretations of results and is therefore regarded by many to be unreliable for determining biogenicity when used alone.^[23]^[24] Perhaps the most compelling argument to date is based on high spatial resolution electron microscopy like scanning and transmission electron microscopy.^[19] This study concludes that the nano-scale morphology of the filaments and the distribution of the carbonaceous matter are inconsistent with a biological origin for the filaments. Instead, it is more likely that the hydrothermal conditions have assisted in the heating, hydration and exfoliation of potassium micas on which barium, iron and carbonate have secondarily been adsorbed.

Carbonaceous structures appearing to be of biological origin have also been discovered in the 3.47 billion year-old Mount Ada Basalt, a rock layer that is a few million years older than the Apex chert. However, the biogenicity of these supposed fossils has also been disputed, with some studies finding abiotic processes to be a more likely culprit for their formation.^[11]

Additional potential bioindicators from the Precambrian have been found in the region, including carbonaceous microfossils in the northeastern Pilbara Craton.^[25]

References[edit]

^ ^a ^b ^c ^d ^e ^f ^g Hickman and Van Kranendonk, Arthur and Martin (2012). "Early Earth evolution: evidence from the 3.5–1.8 Ga geological history of the Pilbara region of Western Australia" (PDF). Episodes. 35 (1): 283–297. doi:10.18814/epiiugs/2012/v35i1/028.
^ "CAPAD 2014". Retrieved 1 April 2023.
^ Djokic, Tara; Van Kranendonk, Martin J.; Campbell, Kathleen A.; Walter, Malcolm R.; Ward, Colin R. (9 May 2017). "Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits". Nature Communications. 8: 15263. Bibcode:2017NatCo...815263D. doi:10.1038/ncomms15263. PMC 5436104. PMID 28486437.
^ "Dresser Formation - Pilbara". pilbara.mq.edu.au.
^ Noffke, N; Christian, D; Wacey, D; Hazen, RM (December 2013). "Microbially induced sedimentary structures recording an ancient ecosystem in the ca. 3.48 billion-year-old Dresser Formation, Pilbara, Western Australia". Astrobiology. 13 (12): 1103–24. Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. PMC 3870916. PMID 24205812.
^ Staff (9 May 2017). "Oldest evidence of life on land found in 3.48-billion-year-old Australian rocks". Phys.org. Retrieved 13 May 2017.
^ Van Kranendonk, Martin J.; Philippot, Pascal; Lepot, Kevin; Bodorkos, Simon; Pirajno, Franco (10 November 2008). "Geological setting of Earth's oldest fossils in the ca. 3.5 Ga Dresser Formation, Pilbara Craton, Western Australia". Precambrian Research. 167 (1–2): 93–124. Bibcode:2008PreR..167...93V. doi:10.1016/j.precamres.2008.07.003. Retrieved 30 December 2022.
^ Tyrell, Kelly April (18 December 2017). "Oldest fossils ever found show life on Earth began before 3.5 billion years ago". University of Wisconsin-Madison. Retrieved 27 December 2017.
^ Schopf, J. William; Kitajima, Kouki; Spicuzza, Michael J.; Kudryavtsev, Anatolly B.; Valley, John W. (2017). "SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions". PNAS. 115 (1): 53–58. doi:10.1073/pnas.1718063115. PMC 5776830. PMID 29255053.
^ Schopf, J. William (9 May 2006). "Fossil evidence of Archaean life". Philosophical Transactions of the Royal Society B. 361 (1470): 869–885. doi:10.1098/rstb.2006.1834. PMC 1578735. PMID 16754604.
^ ^a ^b Alleon, Julien; Flannery, David T.; Ferralis, Nicola; Williford, Kenneth H.; Zhang, Yong; Schuessler, Jan A.; Summons, Roger E. (13 November 2019). "Organo-mineral associations in chert of the 3.5 Ga Mount Ada Basalt raise questions about the origin of organic matter in Paleoarchean hydrothermally influenced sediments". Scientific Reports. 9 (1): 16712. Bibcode:2019NatSR...916712A. doi:10.1038/s41598-019-53272-5. PMC 6853986. PMID 31723181. S2CID 207986473.
^ Schopf, J.; Packer, B. (3 July 1987). "Early Archean (3.3-billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia". Science. 237 (4810): 70–73. Bibcode:1987Sci...237...70S. doi:10.1126/science.11539686. ISSN 0036-8075. PMID 11539686.
^ Schopf, J. W. (30 April 1993). "Microfossils of the Early Archean Apex Chert: New Evidence of the Antiquity of Life". Science. 260 (5108): 640–646. Bibcode:1993Sci...260..640S. doi:10.1126/science.260.5108.640. ISSN 0036-8075. PMID 11539831. S2CID 2109914.
^ ^a ^b ^c Brasier, Martin D.; Green, Owen R.; Jephcoat, Andrew P.; Kleppe, Annette K.; Van Kranendonk, Martin J.; Lindsay, John F.; Steele, Andrew; Grassineau, Nathalie V. (March 2002). "Questioning the evidence for Earth's oldest fossils". Nature. 416 (6876): 76–81. Bibcode:2002Natur.416...76B. doi:10.1038/416076a. ISSN 1476-4687. PMID 11882895. S2CID 819491.
^ ^a ^b Brasier, M.; Green, O.; Lindsay, J.; McLoughlin, N.; Steele, A.; Stoakes, C. (21 October 2005). "Critical testing of Earth's oldest putative fossil assemblage from the ~3.5 Ga Apex chert, Chinaman Creek, Western Australia". Precambrian Research. 140 (1–2): 55–102. Bibcode:2005PreR..140...55B. doi:10.1016/j.precamres.2005.06.008. ISSN 0301-9268.
^ Vankranendonk, M. (1 February 2006). "Volcanic degassing, hydrothermal circulation and the flourishing of early life on Earth: A review of the evidence from c. 3490-3240 Ma rocks of the Pilbara Supergroup, Pilbara Craton, Western Australia". Earth-Science Reviews. 74 (3–4): 197–240. Bibcode:2006ESRv...74..197V. doi:10.1016/j.earscirev.2005.09.005. ISSN 0012-8252.
^ Pinti, Daniele L.; Mineau, Raymond; Clement, Valentin (September 2009). "Hydrothermal alteration and microfossil artefacts of the 3,465-million-year-old Apex chert". Nature Geoscience. 2 (9): 640–643. Bibcode:2009NatGe...2..640P. doi:10.1038/ngeo601. ISSN 1752-0908.
^ Olcott Marshall, Alison; Jehlička, Jan; Rouzaud, Jean-Noel; Marshall, Craig P. (1 January 2014). "Multiple generations of carbonaceous material deposited in Apex chert by basin-scale pervasive hydrothermal fluid flow". Gondwana Research. 25 (1): 284–289. Bibcode:2014GondR..25..284O. doi:10.1016/j.gr.2013.04.006. ISSN 1342-937X.
^ ^a ^b Wacey, David; Saunders, Martin; Kong, Charlie; Brasier, Alexander; Brasier, Martin (1 August 2016). "3.46 Ga Apex chert 'microfossils' reinterpreted as mineral artefacts produced during phyllosilicate exfoliation". Gondwana Research. 36: 296–313. Bibcode:2016GondR..36..296W. doi:10.1016/j.gr.2015.07.010. hdl:2164/9044. ISSN 1342-937X.
^ Garcia-Ruiz, J. M. (14 November 2003). "Self-Assembled Silica-Carbonate Structures and Detection of Ancient Microfossils". Science. 302 (5648): 1194–1197. Bibcode:2003Sci...302.1194G. doi:10.1126/science.1090163. ISSN 0036-8075. PMID 14615534. S2CID 12117608.
^ ^a ^b Marshall, Craig P.; Emry, Julienne R.; Olcott Marshall, Alison (April 2011). "Haematite pseudomicrofossils present in the 3.5-billion-year-old Apex Chert". Nature Geoscience. 4 (4): 240–243. Bibcode:2011NatGe...4..240M. doi:10.1038/ngeo1084. ISSN 1752-0908. S2CID 55506242.
^ Schopf, J. William; Kudryavtsev, Anatoliy B.; Agresti, David G.; Wdowiak, Thomas J.; Czaja, Andrew D. (March 2002). "Laser–Raman imagery of Earth's earliest fossils". Nature. 416 (6876): 73–76. Bibcode:2002Natur.416...73S. doi:10.1038/416073a. ISSN 1476-4687. PMID 11882894. S2CID 4382712.
^ Pasteris, Jill Dill; Wopenka, Brigitte (1 December 2003). "Necessary, but Not Sufficient: Raman Identification of Disordered Carbon as a Signature of Ancient Life". Astrobiology. 3 (4): 727–738. Bibcode:2003AsBio...3..727P. doi:10.1089/153110703322736051. ISSN 1531-1074. PMID 14987478.
^ Gregorio, Bradley T. De; Sharp, Thomas G. (1 May 2006). "The structure and distribution of carbon in 3.5 Ga Apex chert: Implications for the biogenicity of Earth's oldest putative microfossils". American Mineralogist. 91 (5–6): 784–789. Bibcode:2006AmMin..91..784D. doi:10.2138/am.2006.2149. ISSN 1945-3027. S2CID 129380309.
^ Sugitani, Kenichiro; et al. (2009). "Taxonomy and biogenicity of Archaean spheroidal microfossils (ca. 3.0 Ga) from the Mount Goldsworthy–Mount Grant area in the northeastern Pilbara Craton, Western Australia". Precambrian Research. 173 (1–4): 50–59. Bibcode:2009PreR..173...50S. doi:10.1016/j.precamres.2009.02.004.

Bibliography[edit]

Kato, Y.; Nakamura, K. (2003). "Origin and global tectonic significance of Early Archean cherts from the Marble Bar greenstone belt, Pilbara Craton, Western Australia". Precambrian Research. 125 (3–4): 191–243. Bibcode:2003PreR..125..191K. doi:10.1016/S0301-9268(03)00043-3.
Oliver, N. H. S.; Cawood, P.A (2001). "Early tectonic dewatering and brecciation on the overturned sequence at Marble Bar, Pilbara Craton, Western Australia: dome-related or not?". Precambrian Research. 105 (1): 1–15. Bibcode:2001PreR..105....1O. doi:10.1016/S0301-9268(00)00098-X.
Terabayashi, M.; Masada, Y.; Ozawa, H. (2003). "Archean ocean-floor metamorphism in the North Pole area, Pilbara Craton, Western Australia". Precambrian Research. 127 (1–3): 167–180. Bibcode:2003PreR..127..167T. doi:10.1016/S0301-9268(03)00186-4.
Zegers, E.; de Wit, M. J.; Dann, J.; White, S. H. (1998). "Vaalbara, Earth's oldest assembled continent? A combined structural, geochronological, and palaeomagnetic test". Terra Nova. 10 (5): 250–259. Bibcode:1998TeNov..10..250Z. CiteSeerX 10.1.1.566.6728. doi:10.1046/j.1365-3121.1998.00199.x. S2CID 52261989.

External links[edit]

[Hick2012-1] ^ ^a ^b ^c ^d ^e ^f ^g Hickman and Van Kranendonk, Arthur and Martin (2012). "Early Earth evolution: evidence from the 3.5–1.8 Ga geological history of the Pilbara region of Western Australia" (PDF). Episodes. 35 (1): 283–297. doi:10.18814/epiiugs/2012/v35i1/028.

[2] "CAPAD 2014". Retrieved 1 April 2023.

[NC-20170509-3] Djokic, Tara; Van Kranendonk, Martin J.; Campbell, Kathleen A.; Walter, Malcolm R.; Ward, Colin R. (9 May 2017). "Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits". Nature Communications. 8: 15263. Bibcode:2017NatCo...815263D. doi:10.1038/ncomms15263. PMC 5436104. PMID 28486437.

[dresser-4] "Dresser Formation - Pilbara". pilbara.mq.edu.au.

[Noffke-5] Noffke, N; Christian, D; Wacey, D; Hazen, RM (December 2013). "Microbially induced sedimentary structures recording an ancient ecosystem in the ca. 3.48 billion-year-old Dresser Formation, Pilbara, Western Australia". Astrobiology. 13 (12): 1103–24. Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. PMC 3870916. PMID 24205812.

[PO-20170509-6] Staff (9 May 2017). "Oldest evidence of life on land found in 3.48-billion-year-old Australian rocks". Phys.org. Retrieved 13 May 2017.

[7] Van Kranendonk, Martin J.; Philippot, Pascal; Lepot, Kevin; Bodorkos, Simon; Pirajno, Franco (10 November 2008). "Geological setting of Earth's oldest fossils in the ca. 3.5 Ga Dresser Formation, Pilbara Craton, Western Australia". Precambrian Research. 167 (1–2): 93–124. Bibcode:2008PreR..167...93V. doi:10.1016/j.precamres.2008.07.003. Retrieved 30 December 2022.

[WU-20171218-8] Tyrell, Kelly April (18 December 2017). "Oldest fossils ever found show life on Earth began before 3.5 billion years ago". University of Wisconsin-Madison. Retrieved 27 December 2017.

[PNAS-2017-9] Schopf, J. William; Kitajima, Kouki; Spicuzza, Michael J.; Kudryavtsev, Anatolly B.; Valley, John W. (2017). "SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions". PNAS. 115 (1): 53–58. doi:10.1073/pnas.1718063115. PMC 5776830. PMID 29255053.

[10] Schopf, J. William (9 May 2006). "Fossil evidence of Archaean life". Philosophical Transactions of the Royal Society B. 361 (1470): 869–885. doi:10.1098/rstb.2006.1834. PMC 1578735. PMID 16754604.

[AlleonEtAl2019-11] Alleon, Julien; Flannery, David T.; Ferralis, Nicola; Williford, Kenneth H.; Zhang, Yong; Schuessler, Jan A.; Summons, Roger E. (13 November 2019). "Organo-mineral associations in chert of the 3.5 Ga Mount Ada Basalt raise questions about the origin of organic matter in Paleoarchean hydrothermally influenced sediments". Scientific Reports. 9 (1): 16712. Bibcode:2019NatSR...916712A. doi:10.1038/s41598-019-53272-5. PMC 6853986. PMID 31723181. S2CID 207986473.

[12] Schopf, J.; Packer, B. (3 July 1987). "Early Archean (3.3-billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia". Science. 237 (4810): 70–73. Bibcode:1987Sci...237...70S. doi:10.1126/science.11539686. ISSN 0036-8075. PMID 11539686.

[13] Schopf, J. W. (30 April 1993). "Microfossils of the Early Archean Apex Chert: New Evidence of the Antiquity of Life". Science. 260 (5108): 640–646. Bibcode:1993Sci...260..640S. doi:10.1126/science.260.5108.640. ISSN 0036-8075. PMID 11539831. S2CID 2109914.

[:0-14] Brasier, Martin D.; Green, Owen R.; Jephcoat, Andrew P.; Kleppe, Annette K.; Van Kranendonk, Martin J.; Lindsay, John F.; Steele, Andrew; Grassineau, Nathalie V. (March 2002). "Questioning the evidence for Earth's oldest fossils". Nature. 416 (6876): 76–81. Bibcode:2002Natur.416...76B. doi:10.1038/416076a. ISSN 1476-4687. PMID 11882895. S2CID 819491.

[:1-15] Brasier, M.; Green, O.; Lindsay, J.; McLoughlin, N.; Steele, A.; Stoakes, C. (21 October 2005). "Critical testing of Earth's oldest putative fossil assemblage from the ~3.5 Ga Apex chert, Chinaman Creek, Western Australia". Precambrian Research. 140 (1–2): 55–102. Bibcode:2005PreR..140...55B. doi:10.1016/j.precamres.2005.06.008. ISSN 0301-9268.

[16] Vankranendonk, M. (1 February 2006). "Volcanic degassing, hydrothermal circulation and the flourishing of early life on Earth: A review of the evidence from c. 3490-3240 Ma rocks of the Pilbara Supergroup, Pilbara Craton, Western Australia". Earth-Science Reviews. 74 (3–4): 197–240. Bibcode:2006ESRv...74..197V. doi:10.1016/j.earscirev.2005.09.005. ISSN 0012-8252.

[17] Pinti, Daniele L.; Mineau, Raymond; Clement, Valentin (September 2009). "Hydrothermal alteration and microfossil artefacts of the 3,465-million-year-old Apex chert". Nature Geoscience. 2 (9): 640–643. Bibcode:2009NatGe...2..640P. doi:10.1038/ngeo601. ISSN 1752-0908.

[18] Olcott Marshall, Alison; Jehlička, Jan; Rouzaud, Jean-Noel; Marshall, Craig P. (1 January 2014). "Multiple generations of carbonaceous material deposited in Apex chert by basin-scale pervasive hydrothermal fluid flow". Gondwana Research. 25 (1): 284–289. Bibcode:2014GondR..25..284O. doi:10.1016/j.gr.2013.04.006. ISSN 1342-937X.

[:2-19] Wacey, David; Saunders, Martin; Kong, Charlie; Brasier, Alexander; Brasier, Martin (1 August 2016). "3.46 Ga Apex chert 'microfossils' reinterpreted as mineral artefacts produced during phyllosilicate exfoliation". Gondwana Research. 36: 296–313. Bibcode:2016GondR..36..296W. doi:10.1016/j.gr.2015.07.010. hdl:2164/9044. ISSN 1342-937X.

[20] Garcia-Ruiz, J. M. (14 November 2003). "Self-Assembled Silica-Carbonate Structures and Detection of Ancient Microfossils". Science. 302 (5648): 1194–1197. Bibcode:2003Sci...302.1194G. doi:10.1126/science.1090163. ISSN 0036-8075. PMID 14615534. S2CID 12117608.

[:3-21] Marshall, Craig P.; Emry, Julienne R.; Olcott Marshall, Alison (April 2011). "Haematite pseudomicrofossils present in the 3.5-billion-year-old Apex Chert". Nature Geoscience. 4 (4): 240–243. Bibcode:2011NatGe...4..240M. doi:10.1038/ngeo1084. ISSN 1752-0908. S2CID 55506242.

[22] Schopf, J. William; Kudryavtsev, Anatoliy B.; Agresti, David G.; Wdowiak, Thomas J.; Czaja, Andrew D. (March 2002). "Laser–Raman imagery of Earth's earliest fossils". Nature. 416 (6876): 73–76. Bibcode:2002Natur.416...73S. doi:10.1038/416073a. ISSN 1476-4687. PMID 11882894. S2CID 4382712.

[23] Pasteris, Jill Dill; Wopenka, Brigitte (1 December 2003). "Necessary, but Not Sufficient: Raman Identification of Disordered Carbon as a Signature of Ancient Life". Astrobiology. 3 (4): 727–738. Bibcode:2003AsBio...3..727P. doi:10.1089/153110703322736051. ISSN 1531-1074. PMID 14987478.

[24] Gregorio, Bradley T. De; Sharp, Thomas G. (1 May 2006). "The structure and distribution of carbon in 3.5 Ga Apex chert: Implications for the biogenicity of Earth's oldest putative microfossils". American Mineralogist. 91 (5–6): 784–789. Bibcode:2006AmMin..91..784D. doi:10.2138/am.2006.2149. ISSN 1945-3027. S2CID 129380309.

[25] Sugitani, Kenichiro; et al. (2009). "Taxonomy and biogenicity of Archaean spheroidal microfossils (ca. 3.0 Ga) from the Mount Goldsworthy–Mount Grant area in the northeastern Pilbara Craton, Western Australia". Precambrian Research. 173 (1–4): 50–59. Bibcode:2009PreR..173...50S. doi:10.1016/j.precamres.2009.02.004.

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@@ Line 1: / Line 1: @@
 {{short description|Old and stable part of the continental lithosphere located in Pilbara, Western Australia}}
 {{Use dmy dates|date=September 2020}}
+{{Infobox rockunit
-[[Image:IBRA 6.1 Pilbara.png|thumb|upright=1.3|Map of Australia with the Pilbara region highlighted in red.]]
+| name           = Pilbara Craton
+| period         = Archean
+| age            = {{Long fossil range|3800|1700|Age [[Archean]]|ref=<ref name=Hick2012/>}}
+| image          = Pilbara craton from satellite.jpg
+| imagesize      =
+| caption        = Satellite view in 2013 of Pilbara Craton
+| type           = [[Geological formation]]
+| prilithology   = [[Granite]]
+| otherlithology = [[Greenstone belt|Greenstone]]
+| unitof         =
+| subunits       =
+| underlies      =
+| overlies       =
+| thickness      = up to {{Convert|20|km|abbr=on}}
+| area           = Estimated {{convert|250000|km2|abbr=on}},<ref name=Hick2012/> Pilbara IRBA v7 region {{convert|178231.26|km2|abbr=on}}<ref>{{cite web|url=https://www.dcceew.gov.au/environment/land/nrs/science/capad/2014|title= CAPAD 2014|access-date=2023-04-01}}</ref>
+| map            = Image:IBRA 6.1 Pilbara.png
+| map_caption    = Map of Australia with the Pilbara region highlighted in red.
+<!----Location---->
+| location       =
+| coordinates    = <!--{{Coord||N||W|display=inline}}--->
+| region         = [[Western Australia]]
+| country        = [[Australia]]
+| extent         =
+<!--Type section--->
+| namedfor       = [[Pilbara]]<!--Usually a nearby town-->
+| namedby        = See [[Pilbara#Etymology]]<!--Author of defining paper-->
+| year_ts        = <!--Year of definition-->
+| location_ts    = <!--Place,mountain,...-->
+| coordinates_ts = <!--{{Coord||N||W|display=inline}}---> <!--Geographic coordinates-->
+| paleocoordinates_ts = <!--{{Coord||N||W|display=inline}}---> <!--Paleocoordinates-->
+| region_ts      = <!--Region of type section-->
+| country_ts     = <!--Country of type section-->
+| thickness_ts   = <!--Thickness at type section-->
+}}
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+{{Annotation |0|24|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|36|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|48|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|60|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|72|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|84|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|96|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|108|▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮▮|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=white}}
+{{Annotation |0|0|KEY|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=black}}
+{{Annotation |5| 12|Pilbara Craton subregions:|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=black}}
+{{Annotation |5| 24|PIL01 -|text-align=left | font-size=12 | font-weight= | font-family= Arial| background-color=#FFFFFF | color=black}}
+{{Annotation |52| 24|Chichester|text-align=left | font-size=12 | font-weight= | font-family= Arial| background-color=#CBDAB1 | color=black}}
+{{Annotation |5| 36|PIL02 -|text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#FFFFFF | color=black}}
+{{Annotation |52| 36|Fortescue|text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#CBDAB1 | color=black}}
+{{Annotation |5| 48|PIL03 -|text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#FFFFFF | color=black}}
+{{Annotation |52| 48|Hamersley|text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#CBDAB1 | color=black}}
+{{Annotation |5| 60|PIL04 -| text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#FFFFFF | color=#black}}
+{{Annotation |52| 60|Roebourne| text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#CBDAB1 | color=black}}
+{{Annotation |5| 72|Carnarvon subregion:|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=black}}
+{{Annotation |5| 84|CAR01 -| text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#FFFFFF | color=black}}
+{{Annotation |52| 84|Cape Range| text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#F8D9AA | color=black}}
+{{Annotation |5| 96|Gascoyne subregion:|text-align=left | font-size=12 | font-weight=bold | font-family=Arial | background-color= | color=black}}
+{{Annotation |5| 108|GAS01 - | text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color= #FFFFFF| color=black}}
+{{Annotation |52| 108|Ashburton | text-align=left | font-size=12 | font-weight= | font-family=Arial | background-color=#E7E7A2 | color=black}}
+| caption = Pilbara Craton part of the [[continental lithosphere]] using version 7 of [[Interim Biogeographic Regionalisation for Australia|IBRA classification]]. The geo-ecosystems of the PIL02(Fortescue) area in particular are usually on much younger exposed rock formations (< 1.7 Ga) than the lithology discussed in this article.
+}}
 The '''Pilbara Craton''' is an old and stable part of the [[continental lithosphere]] located in the [[Pilbara]] region of [[Western Australia]].
-The Pilbara Craton is one of only two pristine [[Archean|Archaean]] 3.6–2.7 [[Gigaannum|Ga]] (billion years ago) crusts identified on the Earth, along with the [[Kaapvaal Craton]] in [[South Africa]]. Both locations may have once been part of the [[Vaalbara]] supercontinent or the continent of [[Ur (continent)|Ur]].
+The Pilbara Craton is one of only two pristine [[Archean|Archaean]] 3.8–2.7 [[Gigaannum|Ga]] (billion years ago) crusts identified on the Earth, along with the [[Kaapvaal Craton]] in [[South Africa]]. The youngest rocks are 1.7 Ga old in the historic area assigned to the Craton.<ref name=Hick2012>{{cite journal|last1=Hickman and Van Kranendonk|first1=Arthur and Martin|title=Early Earth evolution: evidence from the 3.5–1.8 Ga geological history of the Pilbara region of Western Australia|journal=Episodes|date=2012|volume=35|issue=1|pages=283–297|doi=10.18814/epiiugs/2012/v35i1/028|url=http://aca.unsw.edu.au/sites/default/files/publications/Pilbara_Episodes_2012.pdf|doi-access=free}}</ref> Both locations may have once been part of the [[Vaalbara]] supercontinent or the continent of [[Ur (continent)|Ur]].
+There are two subregional geographical classification regimes used, being:
-The eastern portion is called the [[Eastern Pilbara Craton]].
+# The [[Interim Biogeographic Regionalisation for Australia]] based upon interacting geo-ecosystems
+# Based on geology alone where the eastern continuous oldest portion is called the [[Eastern Pilbara Craton]] and younger surface lithologies within the larger craton have different names.
+[[File:Pilbara Craton Region Map.pdf|thumb|The currently exposed continuous Pilbara Craton in red, the Eastern Pilbara region outlined in blue, and detail of local [[lithology|lithologies]]. However this map does not show other discontinuous exposed oldest rocks of the Pilbara Craton. Accordingly a reader should refer to the references for more detailed geological mapping which is not reproduced here for copyright reasons.]]
+== Geology ==
+{{main|Eastern Pilbara Craton}}
+The most important part of the Pilbara Craton to understand the early Earth crust is called the [[Eastern Pilbara Craton]], where still exposed today, are crustal rocks that are up to 3.8 billion years old and intrusive granitic domes along with greenstone belts that are about 3.5 to 3.2 billion years old.<ref name=Hick2012/> The geology was reassessed in 2007 with the separation out from the geologically named Pilbara Craton of a thick succession of interbedded clastic or chemical sedimentary rocks and volcanic rocks forming the Fortescue, Hamersley, and Turee Creek basins that are usually aged from 2.78–2.42 billion years old and the younger volcano-sedimentary Ashburton Basin aged from 2.21–1.79 billion years ago.<ref name=Hick2012/> A surface region between the Fortescue and Hamersley basins is even younger, at less than 1.7 billion years old, as are the surrounding geo-ecosystems surface rocks to the Pilbara Craton. It is important to note that to the east and south of the Eastern Pilbara Craton there are significant outcrops of the very old rocks and that these are confined to the traditional area of the Pilbara Craton which is inferred to be subsurface for more than half its area.<ref name=Hick2012/>
+=== Mineralogy ===
+There are extensive high quality [[iron ore]] deposits and also economic to mine [[gold]], [[silver]], [[copper]], [[nickel]], [[lead]], [[zinc]], [[molybdenum]], [[vanadium]] and [[fluorite]] deposits.<ref name=Hick2012/>
 == Evidence of earliest life ==
-In May 2017, evidence of the [[Earliest known life forms|earliest known life]] [[Evolutionary history of life#Colonization of land|on land]] may have been found in 3.48-billion-year-old [[geyserite]] and other related mineral deposits (often found around [[hot spring]]s and [[geyser]]s) uncovered in the [[Dresser Formation]] in Pilbara Craton.<ref name="PO-20170509">{{cite news |author=Staff |title=Oldest evidence of life on land found in 3.48-billion-year-old Australian rocks |url=https://phys.org/news/2017-05-oldest-evidence-life-billion-year-old-australian.html |date=9 May 2017 |work=[[Phys.org]] |accessdate=13 May 2017 }}</ref><ref name="NC-20170509">{{cite journal |last1=Djokic |first1=Tara |last2=Van Kranendonk |first2=Martin J. |last3=Campbell |first3=Kathleen A. |last4=Walter |first4=Malcolm R. |last5=Ward |first5=Colin R. |title=Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits |date=9 May 2017 |journal=[[Nature Communications]] |volume=8 |pages=15263 |doi=10.1038/ncomms15263 |pmid=28486437 |pmc=5436104 |bibcode=2017NatCo...815263D }}</ref><ref name="dresser">{{cite web |title=Dresser Formation - Pilbara |url=https://pilbara.mq.edu.au/wiki/Dresser_Formation |website=pilbara.mq.edu.au}}</ref><ref name="Noffke">{{cite journal |last1=Noffke |first1=N |last2=Christian |first2=D |last3=Wacey |first3=D |last4=Hazen |first4=RM |title=Microbially induced sedimentary structures recording an ancient ecosystem in the ca. 3.48 billion-year-old Dresser Formation, Pilbara, Western Australia. |journal=Astrobiology |date=December 2013 |volume=13 |issue=12 |pages=1103–24 |doi=10.1089/ast.2013.1030 |pmid=24205812|pmc=3870916 |bibcode=2013AsBio..13.1103N }}</ref>
+Evidence of the [[Earliest known life forms|earliest known life]] [[Evolutionary history of life#Colonization of land|on land]] may have been found in 3.48-billion-year-old [[geyserite]] and other related mineral deposits (often found around [[hot spring]]s and [[geyser]]s) uncovered in the [[Dresser Formation]] in the Pilbara Craton.<ref name="NC-20170509">{{cite journal |last1=Djokic |first1=Tara |last2=Van Kranendonk |first2=Martin J. |last3=Campbell |first3=Kathleen A. |last4=Walter |first4=Malcolm R. |last5=Ward |first5=Colin R. |title=Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits |date=9 May 2017 |journal=[[Nature Communications]] |volume=8 |pages=15263 |doi=10.1038/ncomms15263 |pmid=28486437 |pmc=5436104 |bibcode=2017NatCo...815263D }}</ref><ref name="dresser">{{cite web |title=Dresser Formation - Pilbara |url=https://pilbara.mq.edu.au/wiki/Dresser_Formation |website=pilbara.mq.edu.au}}</ref><ref name="Noffke">{{cite journal |last1=Noffke |first1=N |author1-link=Nora Noffke |last2=Christian |first2=D |last3=Wacey |first3=D |last4=Hazen |first4=RM |title=Microbially induced sedimentary structures recording an ancient ecosystem in the ca. 3.48 billion-year-old Dresser Formation, Pilbara, Western Australia. |journal=Astrobiology |date=December 2013 |volume=13 |issue=12 |pages=1103–24 |doi=10.1089/ast.2013.1030 |pmid=24205812|pmc=3870916 |bibcode=2013AsBio..13.1103N }}</ref> Biogenic sedimentary structures (microbialites) such as stromatolites and MISS were described from tidal, lagoonal and subtidal coastal settings that can be reconstructed from the Dresser stratigraphy as well.<ref name="PO-20170509">{{cite news |author=Staff |title=Oldest evidence of life on land found in 3.48-billion-year-old Australian rocks |url=https://phys.org/news/2017-05-oldest-evidence-life-billion-year-old-australian.html |date=9 May 2017 |work=[[Phys.org]] |accessdate=13 May 2017 }}</ref> The rocks of the Dresser Formation display evidence of [[haematite]] alteration that may have been microbially influenced.<ref>{{cite journal |last1=Van Kranendonk |first1=Martin J. |last2=Philippot |first2=Pascal |last3=Lepot |first3=Kevin |last4=Bodorkos |first4=Simon |last5=Pirajno |first5=Franco |date=10 November 2008 |title=Geological setting of Earth's oldest fossils in the ca. 3.5 Ga Dresser Formation, Pilbara Craton, Western Australia |url=https://www.sciencedirect.com/science/article/abs/pii/S0301926808001551 |journal=[[Precambrian Research]] |volume=167 |issue=1–2 |pages=93–124 |doi=10.1016/j.precamres.2008.07.003 |bibcode=2008PreR..167...93V |access-date=30 December 2022}}</ref>
+[[File:Apex_Chert.jpg|thumb|left|alt=A specimen of Apex chert.|Apex chert]]
+The earliest ''direct'' evidence of [[Earliest known life forms|life on Earth]] may be fossils of [[microorganism]]s [[Permineralization|permineralized]] in 3.465-billion-year-old [[Australia]]n Apex [[chert]] rocks.<ref name="WU-20171218">{{cite web |last=Tyrell |first=Kelly April |title=Oldest fossils ever found show life on Earth began before 3.5 billion years ago |url=https://news.wisc.edu/oldest-fossils-ever-found-show-life-on-earth-began-before-3-5-billion-years-ago/ |date=18 December 2017 |work=[[University of Wisconsin-Madison]] |accessdate=27 December 2017 }}</ref><ref name="PNAS-2017">{{cite journal |last1=Schopf |first1=J. William |last2=Kitajima |first2=Kouki |last3=Spicuzza |first3=Michael J. |last4=Kudryavtsev |first4=Anatolly B. |last5=Valley |first5=John W. |title=SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions |date=2017 |journal=[[Proceedings of the National Academy of Sciences of the United States of America|PNAS]] |volume=115 |issue=1 |pages=53–58 |doi=10.1073/pnas.1718063115 |pmid=29255053 |pmc=5776830 |doi-access=free }}</ref> However, the evidence for the biogenicity of these microstructures has been thoroughly debated.<ref>{{cite journal |last1=Schopf |first1=J. William |date=9 May 2006 |title=Fossil evidence of Archaean life |journal=Philosophical Transactions of the Royal Society B |volume=361 |issue=1470 |pages=869–885 |doi=10.1098/rstb.2006.1834 |pmid=16754604 |pmc=1578735 }}</ref><ref name="AlleonEtAl2019">{{cite journal |last1=Alleon |first1=Julien |last2=Flannery |first2=David T. |last3=Ferralis |first3=Nicola |last4=Williford |first4=Kenneth H. |last5=Zhang |first5=Yong |last6=Schuessler |first6=Jan A. |last7=Summons |first7=Roger E. |date=13 November 2019 |title=Organo-mineral associations in chert of the 3.5 Ga Mount Ada Basalt raise questions about the origin of organic matter in Paleoarchean hydrothermally influenced sediments |journal=Scientific Reports |volume=9 |issue=1 |page=16712 |doi=10.1038/s41598-019-53272-5 |pmid=31723181 |s2cid=207986473 |pmc=6853986 |bibcode=2019NatSR...916712A }}</ref> Originally, 11 taxa were described from a deposit thought to be located at the mouth of a river due to certain characteristics like rounded and sorted grains.<ref>{{Cite journal|last1=Schopf|first1=J.|last2=Packer|first2=B.|date=1987-07-03|title=Early Archean (3.3-billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia|url=https://www.science.org/doi/10.1126/science.11539686|journal=Science|language=en|volume=237|issue=4810|pages=70–73|doi=10.1126/science.11539686|pmid=11539686|bibcode=1987Sci...237...70S|issn=0036-8075}}</ref><ref>{{Cite journal|last=Schopf|first=J. W.|date=1993-04-30|title=Microfossils of the Early Archean Apex Chert: New Evidence of the Antiquity of Life|url=https://www.science.org/doi/10.1126/science.260.5108.640|journal=Science|language=en|volume=260|issue=5108|pages=640–646|doi=10.1126/science.260.5108.640|pmid=11539831|bibcode=1993Sci...260..640S|s2cid=2109914|issn=0036-8075}}</ref> Extensive field mapping and [[Petrogenesis|petrogenetic]] analysis has since shown the setting for the purported [[microfossils]] to be [[Hydrothermal vent|hydrothermal]]<ref name=":0">{{Cite journal|last1=Brasier|first1=Martin D.|last2=Green|first2=Owen R.|last3=Jephcoat|first3=Andrew P.|last4=Kleppe|first4=Annette K.|last5=Van Kranendonk|first5=Martin J.|last6=Lindsay|first6=John F.|last7=Steele|first7=Andrew|last8=Grassineau|first8=Nathalie V.|date=March 2002|title=Questioning the evidence for Earth's oldest fossils|url=https://www.nature.com/articles/416076a|journal=Nature|language=en|volume=416|issue=6876|pages=76–81|doi=10.1038/416076a|pmid=11882895|bibcode=2002Natur.416...76B|s2cid=819491|issn=1476-4687}}</ref><ref name=":1">{{Cite journal|date=2005-10-21|title=Critical testing of Earth's oldest putative fossil assemblage from the ~3.5 Ga Apex chert, Chinaman Creek, Western Australia|url=https://www.sciencedirect.com/science/article/abs/pii/S0301926805000926|journal=Precambrian Research|language=en|volume=140|issue=1–2|pages=55–102|doi=10.1016/j.precamres.2005.06.008|issn=0301-9268|last1=Brasier|first1=M.|last2=Green|first2=O.|last3=Lindsay|first3=J.|last4=McLoughlin|first4=N.|last5=Steele|first5=A.|last6=Stoakes|first6=C.|bibcode=2005PreR..140...55B}}</ref> and this is widely supported.<ref>{{Cite journal|date=2006-02-01|title=Volcanic degassing, hydrothermal circulation and the flourishing of early life on Earth: A review of the evidence from c. 3490-3240 Ma rocks of the Pilbara Supergroup, Pilbara Craton, Western Australia|url=https://www.sciencedirect.com/science/article/abs/pii/S0012825205001431|journal=Earth-Science Reviews|language=en|volume=74|issue=3–4|pages=197–240|doi=10.1016/j.earscirev.2005.09.005|issn=0012-8252|last1=Vankranendonk|first1=M.|bibcode=2006ESRv...74..197V}}</ref><ref>{{Cite journal|last1=Pinti|first1=Daniele L.|last2=Mineau|first2=Raymond|last3=Clement|first3=Valentin|date=September 2009|title=Hydrothermal alteration and microfossil artefacts of the 3,465-million-year-old Apex chert|url=https://www.nature.com/articles/ngeo601|journal=Nature Geoscience|language=en|volume=2|issue=9|pages=640–643|doi=10.1038/ngeo601|bibcode=2009NatGe...2..640P|issn=1752-0908}}</ref><ref>{{Cite journal|date=2014-01-01|title=Multiple generations of carbonaceous material deposited in Apex chert by basin-scale pervasive hydrothermal fluid flow|url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X13001512|journal=Gondwana Research|language=en|volume=25|issue=1|pages=284–289|doi=10.1016/j.gr.2013.04.006|issn=1342-937X|last1=Olcott Marshall|first1=Alison|last2=Jehlička|first2=Jan|last3=Rouzaud|first3=Jean-Noel|last4=Marshall|first4=Craig P.|bibcode=2014GondR..25..284O}}</ref><ref name=":2">{{Cite journal|date=2016-08-01|title=3.46 Ga Apex chert 'microfossils' reinterpreted as mineral artefacts produced during phyllosilicate exfoliation|url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X15001902|journal=Gondwana Research|language=en|volume=36|pages=296–313|doi=10.1016/j.gr.2015.07.010|issn=1342-937X|hdl=2164/9044|hdl-access=free|last1=Wacey|first1=David|last2=Saunders|first2=Martin|last3=Kong|first3=Charlie|last4=Brasier|first4=Alexander|last5=Brasier|first5=Martin|bibcode=2016GondR..36..296W}}</ref> Consequently, many alternative abiotic explanations have been proposed for the filamentous microstructures including carbonaceous rims around quartz spherules and rhombs,<ref name=":0" /><ref name=":1" /> witherite self-assembled biomorphs<ref>{{Cite journal|last=Garcia-Ruiz|first=J. M.|date=2003-11-14|title=Self-Assembled Silica-Carbonate Structures and Detection of Ancient Microfossils|url=https://www.science.org/doi/10.1126/science.1090163|journal=Science|language=en|volume=302|issue=5648|pages=1194–1197|doi=10.1126/science.1090163|pmid=14615534|bibcode=2003Sci...302.1194G|s2cid=12117608|issn=0036-8075}}</ref> and haematite infilled veinlets.<ref name=":3">{{Cite journal|last1=Marshall|first1=Craig P.|last2=Emry|first2=Julienne R.|last3=Olcott Marshall|first3=Alison|date=April 2011|title=Haematite pseudomicrofossils present in the 3.5-billion-year-old Apex Chert|url=https://www.nature.com/articles/ngeo1084|journal=Nature Geoscience|language=en|volume=4|issue=4|pages=240–243|doi=10.1038/ngeo1084|bibcode=2011NatGe...4..240M|s2cid=55506242 |issn=1752-0908}}</ref> The carbonaceous matter composing the filaments has also been repeatedly examined with [[Raman spectroscopy]]<ref name=":0" /><ref>{{Cite journal|last1=Schopf|first1=J. William|last2=Kudryavtsev|first2=Anatoliy B.|last3=Agresti|first3=David G.|last4=Wdowiak|first4=Thomas J.|last5=Czaja|first5=Andrew D.|date=March 2002|title=Laser–Raman imagery of Earth's earliest fossils|url=https://www.nature.com/articles/416073a|journal=Nature|language=en|volume=416|issue=6876|pages=73–76|doi=10.1038/416073a|pmid=11882894|bibcode=2002Natur.416...73S|s2cid=4382712|issn=1476-4687}}</ref><ref name=":3" /> which has yielded mixed interpretations of results and is therefore regarded by many to be unreliable for determining biogenicity when used alone.<ref>{{Cite journal|last1=Pasteris|first1=Jill Dill|last2=Wopenka|first2=Brigitte|date=2003-12-01|title=Necessary, but Not Sufficient: Raman Identification of Disordered Carbon as a Signature of Ancient Life|url=https://www.liebertpub.com/doi/10.1089/153110703322736051|journal=Astrobiology|volume=3|issue=4|pages=727–738|doi=10.1089/153110703322736051|pmid=14987478|bibcode=2003AsBio...3..727P|issn=1531-1074}}</ref><ref>{{Cite journal|last1=Gregorio|first1=Bradley T. De|last2=Sharp|first2=Thomas G.|date=2006-05-01|title=The structure and distribution of carbon in 3.5 Ga Apex chert: Implications for the biogenicity of Earth's oldest putative microfossils|url=https://www.degruyter.com/document/doi/10.2138/am.2006.2149/html|journal=American Mineralogist|language=en|volume=91|issue=5–6|pages=784–789|doi=10.2138/am.2006.2149|bibcode=2006AmMin..91..784D|s2cid=129380309|issn=1945-3027}}</ref> Perhaps the most compelling argument to date is based on high spatial resolution electron microscopy like [[Scanning electron microscope|scanning]] and [[transmission electron microscopy]].<ref name=":2" /> This study concludes that the nano-scale morphology of the filaments and the distribution of the carbonaceous matter are inconsistent with a biological origin for the filaments. Instead, it is more likely that the [[Hydrothermal vent|hydrothermal]] conditions have assisted in the heating, hydration and exfoliation of potassium micas on which barium, iron and carbonate have secondarily been adsorbed.
+Carbonaceous structures appearing to be of biological origin have also been discovered in the 3.47 billion year-old Mount Ada Basalt, a rock layer that is a few million years older than the Apex chert. However, the biogenicity of these supposed fossils has also been disputed, with some studies finding abiotic processes to be a more likely culprit for their formation.<ref name="AlleonEtAl2019" />
-The earliest ''direct'' evidence of [[Earliest known life forms|life on Earth]] may be fossils of [[microorganism]]s [[Permineralization|permineralized]] in 3.465-billion-year-old [[Australia]]n Apex [[chert]] rocks.<ref name="WU-20171218">{{cite web |last=Tyrell |first=Kelly April |title=Oldest fossils ever found show life on Earth began before 3.5 billion years ago |url=https://news.wisc.edu/oldest-fossils-ever-found-show-life-on-earth-began-before-3-5-billion-years-ago/ |date=18 December 2017 |work=[[University of Wisconsin-Madison]] |accessdate=27 December 2017 }}</ref><ref name="PNAS-2017">{{cite journal |last1=Schopf |first1=J. William |last2=Kitajima |first2=Kouki |last3=Spicuzza |first3=Michael J. |last4=Kudryavtsev |first4=Anatolly B. |last5=Valley |first5=John W. |title=SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions |date=2017 |journal=[[Proceedings of the National Academy of Sciences of the United States of America|PNAS]] |volume=115 |issue=1 |pages=53–58 |doi=10.1073/pnas.1718063115 |pmid=29255053 |pmc=5776830 |doi-access=free }}</ref> However, the evidence for the biogenicity of these microstructures has been thoroughly debated. Originally, 11 taxa were described from a deposit thought to be located at the mouth of a river due to certain characteristics like rounded and sorted grains.<ref>{{Cite journal|last1=Schopf|first1=J.|last2=Packer|first2=B.|date=1987-07-03|title=Early Archean (3.3-billion to 3.5-billion-year-old) microfossils from Warrawoona Group, Australia|url=https://www.science.org/doi/10.1126/science.11539686|journal=Science|language=en|volume=237|issue=4810|pages=70–73|doi=10.1126/science.11539686|pmid=11539686|bibcode=1987Sci...237...70S|issn=0036-8075}}</ref><ref>{{Cite journal|last=Schopf|first=J. W.|date=1993-04-30|title=Microfossils of the Early Archean Apex Chert: New Evidence of the Antiquity of Life|url=https://www.science.org/doi/10.1126/science.260.5108.640|journal=Science|language=en|volume=260|issue=5108|pages=640–646|doi=10.1126/science.260.5108.640|pmid=11539831|bibcode=1993Sci...260..640S|s2cid=2109914|issn=0036-8075}}</ref> Extensive field mapping and [[Petrogenesis|petrogenetic]] analysis has since shown the setting for the purported [[microfossils]] to be [[Hydrothermal vent|hydrothermal]]<ref name=":0">{{Cite journal|last1=Brasier|first1=Martin D.|last2=Green|first2=Owen R.|last3=Jephcoat|first3=Andrew P.|last4=Kleppe|first4=Annette K.|last5=Van Kranendonk|first5=Martin J.|last6=Lindsay|first6=John F.|last7=Steele|first7=Andrew|last8=Grassineau|first8=Nathalie V.|date=March 2002|title=Questioning the evidence for Earth's oldest fossils|url=https://www.nature.com/articles/416076a|journal=Nature|language=en|volume=416|issue=6876|pages=76–81|doi=10.1038/416076a|pmid=11882895|bibcode=2002Natur.416...76B|s2cid=819491|issn=1476-4687}}</ref><ref name=":1">{{Cite journal|date=2005-10-21|title=Critical testing of Earth's oldest putative fossil assemblage from the ∼3.5 Ga Apex chert, Chinaman Creek, Western Australia|url=https://www.sciencedirect.com/science/article/abs/pii/S0301926805000926|journal=Precambrian Research|language=en|volume=140|issue=1–2|pages=55–102|doi=10.1016/j.precamres.2005.06.008|issn=0301-9268|last1=Brasier|first1=M.|last2=Green|first2=O.|last3=Lindsay|first3=J.|last4=McLoughlin|first4=N.|last5=Steele|first5=A.|last6=Stoakes|first6=C.|bibcode=2005PreR..140...55B}}</ref> and this is widely supported.<ref>{{Cite journal|date=2006-02-01|title=Volcanic degassing, hydrothermal circulation and the flourishing of early life on Earth: A review of the evidence from c. 3490-3240 Ma rocks of the Pilbara Supergroup, Pilbara Craton, Western Australia|url=https://www.sciencedirect.com/science/article/abs/pii/S0012825205001431|journal=Earth-Science Reviews|language=en|volume=74|issue=3–4|pages=197–240|doi=10.1016/j.earscirev.2005.09.005|issn=0012-8252|last1=Vankranendonk|first1=M.|bibcode=2006ESRv...74..197V}}</ref><ref>{{Cite journal|last1=Pinti|first1=Daniele L.|last2=Mineau|first2=Raymond|last3=Clement|first3=Valentin|date=September 2009|title=Hydrothermal alteration and microfossil artefacts of the 3,465-million-year-old Apex chert|url=https://www.nature.com/articles/ngeo601|journal=Nature Geoscience|language=en|volume=2|issue=9|pages=640–643|doi=10.1038/ngeo601|bibcode=2009NatGe...2..640P|issn=1752-0908}}</ref><ref>{{Cite journal|date=2014-01-01|title=Multiple generations of carbonaceous material deposited in Apex chert by basin-scale pervasive hydrothermal fluid flow|url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X13001512|journal=Gondwana Research|language=en|volume=25|issue=1|pages=284–289|doi=10.1016/j.gr.2013.04.006|issn=1342-937X|last1=Olcott Marshall|first1=Alison|last2=Jehlička|first2=Jan|last3=Rouzaud|first3=Jean-Noel|last4=Marshall|first4=Craig P.|bibcode=2014GondR..25..284O}}</ref><ref name=":2">{{Cite journal|date=2016-08-01|title=3.46 Ga Apex chert 'microfossils' reinterpreted as mineral artefacts produced during phyllosilicate exfoliation|url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X15001902|journal=Gondwana Research|language=en|volume=36|pages=296–313|doi=10.1016/j.gr.2015.07.010|issn=1342-937X|hdl=2164/9044|hdl-access=free|last1=Wacey|first1=David|last2=Saunders|first2=Martin|last3=Kong|first3=Charlie|last4=Brasier|first4=Alexander|last5=Brasier|first5=Martin|bibcode=2016GondR..36..296W}}</ref> Consequently, many alternative abiotic explanations have been proposed for the filamentous microstructures including carbonaceous rims around quartz spherules and rhombs,<ref name=":0" /><ref name=":1" /> witherite self-assembled biomorphs<ref>{{Cite journal|last=Garcia-Ruiz|first=J. M.|date=2003-11-14|title=Self-Assembled Silica-Carbonate Structures and Detection of Ancient Microfossils|url=https://www.science.org/doi/10.1126/science.1090163|journal=Science|language=en|volume=302|issue=5648|pages=1194–1197|doi=10.1126/science.1090163|pmid=14615534|bibcode=2003Sci...302.1194G|s2cid=12117608|issn=0036-8075}}</ref> and hematite infilled veinlets.<ref name=":3">{{Cite journal|last1=Marshall|first1=Craig P.|last2=Emry|first2=Julienne R.|last3=Olcott Marshall|first3=Alison|date=April 2011|title=Haematite pseudomicrofossils present in the 3.5-billion-year-old Apex Chert|url=https://www.nature.com/articles/ngeo1084|journal=Nature Geoscience|language=en|volume=4|issue=4|pages=240–243|doi=10.1038/ngeo1084|bibcode=2011NatGe...4..240M|issn=1752-0908}}</ref> The carbonaceous matter composing the filaments has also been repeatedly examined with [[Raman spectroscopy]]<ref name=":0" /><ref>{{Cite journal|last1=Schopf|first1=J. William|last2=Kudryavtsev|first2=Anatoliy B.|last3=Agresti|first3=David G.|last4=Wdowiak|first4=Thomas J.|last5=Czaja|first5=Andrew D.|date=March 2002|title=Laser–Raman imagery of Earth's earliest fossils|url=https://www.nature.com/articles/416073a|journal=Nature|language=en|volume=416|issue=6876|pages=73–76|doi=10.1038/416073a|pmid=11882894|bibcode=2002Natur.416...73S|s2cid=4382712|issn=1476-4687}}</ref><ref name=":3" /> which has yielded mixed interpretations of results and is therefore regarded by many to be unreliable for determining biogenicity when used alone.<ref>{{Cite journal|last1=Pasteris|first1=Jill Dill|last2=Wopenka|first2=Brigitte|date=2003-12-01|title=Necessary, but Not Sufficient: Raman Identification of Disordered Carbon as a Signature of Ancient Life|url=https://www.liebertpub.com/doi/10.1089/153110703322736051|journal=Astrobiology|volume=3|issue=4|pages=727–738|doi=10.1089/153110703322736051|pmid=14987478|bibcode=2003AsBio...3..727P|issn=1531-1074}}</ref><ref>{{Cite journal|last1=Gregorio|first1=Bradley T. De|last2=Sharp|first2=Thomas G.|date=2006-05-01|title=The structure and distribution of carbon in 3.5 Ga Apex chert: Implications for the biogenicity of Earth's oldest putative microfossils|url=https://www.degruyter.com/document/doi/10.2138/am.2006.2149/html|journal=American Mineralogist|language=en|volume=91|issue=5–6|pages=784–789|doi=10.2138/am.2006.2149|bibcode=2006AmMin..91..784D|s2cid=129380309|issn=1945-3027}}</ref> Perhaps the most compelling argument to date is based on high spatial resolution electron microscopy like [[Scanning electron microscope|scanning]] and [[transmission electron microscopy]].<ref name=":2" /> This study concludes that the nano-scale morphology of the filaments and the distribution of the carbonaceous matter are inconsistent with a biological origin for the filaments. Instead, it is more likely that the [[Hydrothermal vent|hydrothermal]] conditions have assisted in the heating, hydration and exfoliation of potassium micas on which barium, iron and carbonate have secondarily been adsorbed.
 Additional potential bioindicators from the Precambrian have been found in the region, including carbonaceous [[microfossils]] in the northeastern Pilbara Craton.<ref>{{cite journal|last1=Sugitani|first1=Kenichiro|display-authors=etal|year=2009|title=Taxonomy and biogenicity of Archaean spheroidal microfossils (ca. 3.0 Ga) from the Mount Goldsworthy–Mount Grant area in the northeastern Pilbara Craton, Western Australia|journal=Precambrian Research|volume=173|issue=1–4|pages=50–59|doi=10.1016/j.precamres.2009.02.004|bibcode=2009PreR..173...50S}}</ref>
@@ Line 36: / Line 122: @@
 * {{cite journal|last1=Oliver|first1=N. H. S.|last2=Cawood|first2=P.A|title=Early tectonic dewatering and brecciation on the overturned sequence at Marble Bar, Pilbara Craton, Western Australia: dome-related or not?|journal=Precambrian Research|date=2001|volume=105|issue=1|pages=1–15|doi=10.1016/S0301-9268(00)00098-X|bibcode=2001PreR..105....1O}}
 * {{cite journal|last1=Terabayashi|first1=M.|last2=Masada|first2=Y.|last3=Ozawa|first3=H.|title=Archean ocean-floor metamorphism in the North Pole area, Pilbara Craton, Western Australia|journal=Precambrian Research|date=2003|volume=127|issue=1–3|pages=167–180|doi=10.1016/S0301-9268(03)00186-4|bibcode=2003PreR..127..167T}}
-* {{cite journal|last1=Zegers|first1=E.|last2=de Wit|first2=M. J.|last3=Dann|first3=J.|last4=White|first4=S. H.|title=Vaalbara, Earth's oldest assembled continent? A combined structural, geochronological, and palaeomagnetic test|journal=Terra Nova|date=1998|volume=10|issue=5|pages=250–259|doi=10.1046/j.1365-3121.1998.00199.x|bibcode=1998TeNov..10..250Z|citeseerx=10.1.1.566.6728}}
+* {{cite journal|last1=Zegers|first1=E.|last2=de Wit|first2=M. J.|last3=Dann|first3=J.|last4=White|first4=S. H.|title=Vaalbara, Earth's oldest assembled continent? A combined structural, geochronological, and palaeomagnetic test|journal=Terra Nova|date=1998|volume=10|issue=5|pages=250–259|doi=10.1046/j.1365-3121.1998.00199.x|bibcode=1998TeNov..10..250Z|citeseerx=10.1.1.566.6728|s2cid=52261989 }}
 == External links ==