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Archean
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<h2 id="etymology-and-changes-in-classification">Etymology and changes in classification</h2> <p>The word <i>Archean</i> is derived from the Greek word <i>arkhē</i> (ἀρχή), meaning 'beginning, origin'.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> The <a href="/facts/Pre-Cambrian/zjF3N3Rx">Pre-Cambrian</a> had been believed to be without life (azoic); however, fossils were found in deposits that were judged to belong to the <a href="/facts/Azoic_age/UDzcYSQR">Azoic age</a>. Before the Hadean Eon was recognized, the Archean spanned Earth's early history from its formation about 4,540 million years ago until 2,500 million years ago. </p><p>Instead of being based on <a href="/facts/Stratigraphy/o3J6Ij3R">stratigraphy</a>, the beginning and end of the Archean Eon are defined <a href="/facts/Chronometric_dating/qYHIGBEu">chronometrically</a>. The eon's lower boundary or starting point of 4,031±3 million years ago is officially recognized by the <a href="/facts/International_Commission_on_Stratigraphy/sGDCGGd2">International Commission on Stratigraphy</a>,<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> which is the age of the oldest known intact rock formations on Earth. Evidence of rocks from the preceding Hadean Eon are therefore restricted by definition to non-rock and non-terrestrial sources such as individual mineral grains and lunar samples. </p> <h2 id="geology">Geology</h2> <p>When the Archean began, the Earth's <a href="/facts/Earth%2527s_internal_heat_budget/WhygNFuJ">heat flow</a> was nearly three times as high as it is today, and it was still twice the current level at the transition from the Archean to the Proterozoic (2,500 Ma). The extra heat was partly remnant heat from <a href="/facts/Accretion_(astrophysics)/atcWRsDP">planetary accretion</a>, from the formation of the <a href="/facts/Structure_of_the_Earth/678dYXU7">metallic core</a>, and partly arose from the decay of <a href="/facts/Radioactive/Ya6FVjt4">radioactive</a> elements. As a result, the Earth's mantle was significantly hotter than today.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> </p> <p>Although a few mineral grains have survived from the <a href="/facts/Hadean/j7LWS4ah">Hadean</a>, the oldest rock formations exposed on the surface of the Earth are Archean. Archean rocks are found in <a href="/facts/Geology_of_Greenland/jaXl1XoD">Greenland</a>, <a href="/facts/Geology_of_Siberia/oaCoPEjF">Siberia</a>, the <a href="/facts/Canadian_Shield/TklzY7Ln">Canadian Shield</a>, <a href="/facts/Geology_of_Montana/PVFVjwzs">Montana</a>, <a href="/facts/Geology_of_Wyoming/QkDAmDxC">Wyoming</a> (exposed parts of the <a href="/facts/Wyoming_craton/2xKbCpYD">Wyoming Craton</a>), <a href="/facts/Geology_of_Minnesota/NwVEK3tC">Minnesota</a> (Minnesota River Valley), the <a href="/facts/Baltic_Shield/Um1CVxsI">Baltic Shield</a>, the <a href="/facts/Geology_of_Bulgaria/nYHPvGCA">Rhodope Massif</a>, <a href="/facts/Geology_of_Scotland/DWAICzXq">Scotland</a>, <a href="/facts/Geological_history_of_India/55RzalLU">India</a>, <a href="/facts/Geology_of_Brazil/5dYatmBC">Brazil</a>, western <a href="/facts/Geology_of_Australia/AshxwetY">Australia</a>, and southern <a href="/facts/Geology_of_Africa/FvT1anQQ">Africa</a>. <a href="/facts/Granitic/WdvRm9Ye">Granitic</a> rocks predominate throughout the crystalline remnants of the surviving Archean crust. These include great melt sheets and voluminous <a href="/facts/Intrusive_rock/Wl6xaY1a">plutonic</a> masses of <a href="/facts/Granite/G2evuVKo">granite</a>, <a href="/facts/Diorite/uBrcD9Gw">diorite</a>, <a href="/facts/Layered_intrusion/LVIhCsfC">layered intrusions</a>, <a href="/facts/Anorthosite/69B9Dr1D">anorthosites</a> and <a href="/facts/Monzonite/MyYoBEcq">monzonites</a> known as <a href="/facts/Sanukitoid/n2gDqk9h">sanukitoids</a>. Archean rocks are often heavily metamorphosed deep-water sediments, such as <a href="/facts/Graywacke/Fx5p7h5a">graywackes</a>, <a href="/facts/Mudstone/KWLvUash">mudstones</a>, volcanic sediments, and <a href="/facts/Banded_iron_formation/b1eA2yAk">banded iron formations</a>. <a href="/facts/Volcanic/c2M5upml">Volcanic</a> activity was considerably higher than today, with numerous lava eruptions, including unusual types such as <a href="/facts/Komatiite/haEtqNaG">komatiite</a>.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> <a href="/facts/Carbonate/FES1QHkN">Carbonate</a> rocks are rare, indicating that the oceans were more acidic, due to dissolved <a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a>, than during the Proterozoic.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> <a href="/facts/Greenstone_belt/BVHGpXJG">Greenstone belts</a> are typical Archean formations, consisting of alternating units of metamorphosed <a href="/facts/Mafic/mVL7Ahuw">mafic</a> igneous and sedimentary rocks, including <a href="/facts/Archean_felsic_volcanic_rocks/68LyDhnC">Archean felsic volcanic rocks</a>. The metamorphosed igneous rocks were derived from volcanic <a href="/facts/Island_arc/J7FIJPmy">island arcs</a>, while the metamorphosed sediments represent deep-sea sediments eroded from the neighboring island arcs and deposited in a <a href="/facts/Forearc/FoVAb430">forearc</a> basin. Greenstone belts, which include both types of metamorphosed rock, represent <a href="/facts/Suture_(geology)/CxXa0o5W">sutures</a> between the protocontinents.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>: 302–303 </p><p><a href="/facts/Plate_tectonics/RtRG5lY4">Plate tectonics</a> likely started vigorously in the <a href="/facts/Hadean/j7LWS4ah">Hadean</a>, but slowed down in the Archean.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a><a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> The slowing of plate tectonics was probably due to an increase in the viscosity of the <a href="/facts/Mantle_(geology)/RpDdtjCr">mantle</a> due to outgassing of its water.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> Plate tectonics likely produced large amounts of continental crust, but the deep oceans of the Archean probably covered the continents entirely.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> Only at the end of the Archean did the continents likely emerge from the ocean.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> The emergence of continents towards the end of the Archaean initiated continental weathering that left its mark on the oxygen isotope record by enriching seawater with isotopically light oxygen.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p><p>Due to recycling and metamorphosis of the Archean crust, there is a lack of extensive geological evidence for specific continents. One hypothesis is that rocks that are now in India, western Australia, and southern Africa formed a continent called <a href="/facts/Ur_(continent)/KgpyrRY1">Ur</a> as of 3,100 Ma.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> Another hypothesis, which conflicts with the first, is that rocks from western Australia and southern Africa were assembled in a continent called <a href="/facts/Vaalbara/2Rl6Fa1E">Vaalbara</a> as far back as 3,600 Ma.<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> Archean rock makes up only about 8% of Earth's present-day continental crust; the rest of the Archean continents have been recycled.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> </p><p>By the <a href="/facts/Neoarchean/fCh6XLKA">Neoarchean</a>, plate tectonic activity may have been similar to that of the modern Earth, although there was a significantly greater occurrence of <a href="/facts/Slab_detachment/RBUQHpI9">slab detachment</a> resulting from a hotter mantle, <a href="/facts/Rheology/KexaBNCS">rheologically</a> weaker plates, and increased tensile stresses on <a href="/facts/Subduction/rkasNdTo">subducting</a> plates due to their crustal material metamorphosing from <a href="/facts/Basalt/uhbwGPTb">basalt</a> into <a href="/facts/Eclogite/H2Yy5PhD">eclogite</a> as they sank.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a><a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> There are well-preserved <a href="/facts/Sedimentary_basin/dVkfKMrB">sedimentary basins</a>, and evidence of <a href="/facts/Volcanic_arc/W2WawWYd">volcanic arcs</a>, intracontinental <a href="/facts/Rift/FAWNKCGF">rifts</a>, continent-continent collisions and widespread globe-spanning <a href="/facts/Orogeny/XrvRMpsw">orogenic events</a> suggesting the assembly and destruction of one and perhaps several <a href="/facts/Supercontinent/amID2KQp">supercontinents</a>. Evidence from banded iron formations, <a href="/facts/Chert/pmvbVy6U">chert</a> beds, chemical sediments and <a href="/facts/Basalt/uhbwGPTb">pillow basalts</a> demonstrates that liquid water was prevalent and deep oceanic basins already existed. </p><p>Asteroid impacts were frequent in the early Archean.<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> Evidence from <a href="/facts/Spherule/jywYLNM2">spherule</a> layers suggests that impacts continued into the later Archean, at an average rate of about one impactor with a diameter greater than 10 kilometers (6 mi) every 15 million years. This is about the size of the <a href="/facts/Chicxulub_crater/qVqCqm81">Chicxulub</a> impactor. These impacts would have been an important oxygen sink and would have caused drastic fluctuations of atmospheric oxygen levels.<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> </p> <h2 id="environment">Environment</h2> <p>The Archean atmosphere is thought to have almost completely lacked <a href="/facts/Dioxygen_in_biological_reactions/MW7vayxF">free oxygen</a>; oxygen levels were less than 0.001% of their present atmospheric level,<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a><a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a> with some analyses suggesting they were as low as 0.00001% of modern levels.<a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> However, transient episodes of heightened oxygen concentrations are known from this eon around 2,980–2,960 Ma,<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a> 2,700 Ma,<a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a> and 2,501 Ma.<a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a><a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a> The pulses of increased oxygenation at 2,700 and 2,501 Ma have both been considered by some as potential start points of the <a href="/facts/Great_Oxygenation_Event/LmTyM8jT">Great Oxygenation Event</a>,<a class="footnote-ref" id="fnref:27" href="#fn:27"><sup>27</sup></a><a class="footnote-ref" id="fnref:28" href="#fn:28"><sup>28</sup></a> which most scholars consider to have begun in the <a href="/facts/Paleoproterozoic/gMS69p5r">Paleoproterozoic</a> (c. 2.4 Ga).<a class="footnote-ref" id="fnref:29" href="#fn:29"><sup>29</sup></a><a class="footnote-ref" id="fnref:30" href="#fn:30"><sup>30</sup></a><a class="footnote-ref" id="fnref:31" href="#fn:31"><sup>31</sup></a> Furthermore, oases of relatively high oxygen levels existed in some nearshore shallow marine settings by the Mesoarchean.<a class="footnote-ref" id="fnref:32" href="#fn:32"><sup>32</sup></a> The ocean was broadly <a href="/facts/Reducing_agent/CtfSGVXC">reducing</a> and lacked any persistent redoxcline, a water layer between oxygenated and anoxic layers with a strong <a href="/facts/Reduction%25E2%2580%2593oxidation/Pyd5RVcj">redox</a> gradient, which would become a feature in later, more oxic oceans.<a class="footnote-ref" id="fnref:33" href="#fn:33"><sup>33</sup></a> Despite the lack of free oxygen, the rate of organic carbon burial appears to have been roughly the same as in the present.<a class="footnote-ref" id="fnref:34" href="#fn:34"><sup>34</sup></a> Due to extremely low oxygen levels, sulphate was rare in the Archean ocean, and sulphides were produced primarily through reduction of organically sourced sulphite or through mineralisation of compounds containing reduced sulphur.<a class="footnote-ref" id="fnref:35" href="#fn:35"><sup>35</sup></a> The Archean ocean was enriched in heavier oxygen isotopes relative to the modern ocean, though <a href="/facts/%25CE%259418O/H6r0wQ7R">δ18O</a> values decreased to levels comparable to those of modern oceans over the course of the later part of the eon as a result of increased continental weathering.<a class="footnote-ref" id="fnref:36" href="#fn:36"><sup>36</sup></a> </p><p>Astronomers think that the Sun had about 75–80 percent of its present luminosity,<a class="footnote-ref" id="fnref:37" href="#fn:37"><sup>37</sup></a> yet temperatures on Earth appear to have been near modern levels only 500 million years after Earth's formation (the <a href="/facts/Faint_young_Sun_paradox/Sh4d66XX">faint young Sun paradox</a>). The presence of liquid water is evidenced by certain highly deformed <a href="/facts/Gneiss/rUJYgBHu">gneisses</a> produced by metamorphism of <a href="/facts/Sediment/zsIH1A6U">sedimentary</a> <a href="/facts/Protolith/72uzWogN">protoliths</a>. The moderate temperatures may reflect the presence of greater amounts of greenhouse gases than later in the Earth's history.<a class="footnote-ref" id="fnref:38" href="#fn:38"><sup>38</sup></a><a class="footnote-ref" id="fnref:39" href="#fn:39"><sup>39</sup></a><a class="footnote-ref" id="fnref:40" href="#fn:40"><sup>40</sup></a> Extensive abiotic denitrification took place on the Archean Earth, pumping the greenhouse gas <a href="/facts/Nitrous_oxide/Jvys91lI">nitrous oxide</a> into the atmosphere.<a class="footnote-ref" id="fnref:41" href="#fn:41"><sup>41</sup></a> Alternatively, Earth's <a href="/facts/Albedo/TJDRdKEB">albedo</a> may have been lower at the time, due to less land area and cloud cover.<a class="footnote-ref" id="fnref:42" href="#fn:42"><sup>42</sup></a> </p> <h2 id="early-life">Early life</h2> <p class="note">Main article: <a href="/facts/Earliest_known_life_forms/5voHrbwL">Earliest known life forms</a></p> <p class="note">For details on how life got started, see <a href="/facts/Abiogenesis/BvAmLPQP">Abiogenesis</a>.</p> <p>The processes that gave rise to life on Earth are not completely understood, but there is substantial evidence that life came into existence either near the end of the Hadean Eon or early in the Archean Eon. </p><p>The earliest evidence for life on Earth is <a href="/facts/Graphite/sSf3KMXr">graphite</a> of <a href="/facts/Biogenic_substance/RKUIh7aM">biogenic</a> origin found in 3.7 billion–year-old <a href="/facts/Metasedimentary_rock/IPrKSCun">metasedimentary rocks</a> discovered in <a href="/facts/Kitaa/AfcKWpxd">Western Greenland</a>.<a class="footnote-ref" id="fnref:43" href="#fn:43"><sup>43</sup></a> </p> <p>The earliest identifiable fossils consist of <a href="/facts/Stromatolite/Wr208p5m">stromatolites</a>, which are <a href="/facts/Microbial_mats/qVfYYzvW">microbial mats</a> formed in shallow water by <a href="/facts/Cyanobacteria/S8bKxIU9">cyanobacteria</a>. The earliest stromatolites are found in 3.48 billion-year-old <a href="/facts/Sandstone/RP8B6fqL">sandstone</a> discovered in <a href="/facts/Western_Australia/1ouCbwNh">Western Australia</a>.<a class="footnote-ref" id="fnref:44" href="#fn:44"><sup>44</sup></a><a class="footnote-ref" id="fnref:45" href="#fn:45"><sup>45</sup></a> Stromatolites are found throughout the Archean<a class="footnote-ref" id="fnref:46" href="#fn:46"><sup>46</sup></a> and become common late in the Archean.<a class="footnote-ref" id="fnref:47" href="#fn:47"><sup>47</sup></a>: 307 Cyanobacteria were instrumental in creating free oxygen in the atmosphere. </p><p>Further evidence for early life is found in 3.47 billion-year-old <a href="/facts/Baryte/G6frVDl5">baryte</a>, in the <a href="/facts/Warrawoona_Group/6NAGFyHc">Warrawoona Group</a> of Western Australia. This mineral shows sulfur <a href="/facts/Fractionation/85wUlYTN">fractionation</a> of as much as 21.1%,<a class="footnote-ref" id="fnref:48" href="#fn:48"><sup>48</sup></a> which is evidence of <a href="/facts/Sulfate-reducing_bacteria/uvFQhLWe">sulfate-reducing bacteria</a> that metabolize <a href="/facts/Isotopes_of_sulfur/08Qs8w3o">sulfur-32</a> more readily than sulfur-34.<a class="footnote-ref" id="fnref:49" href="#fn:49"><sup>49</sup></a> </p><p>Evidence of life in the Late Hadean is more controversial. In 2015, biogenic carbon was detected in <a href="/facts/Zircon/84APfbLt">zircons</a> dated to 4.1 billion years ago, but this evidence is preliminary and needs validation.<a class="footnote-ref" id="fnref:50" href="#fn:50"><sup>50</sup></a><a class="footnote-ref" id="fnref:51" href="#fn:51"><sup>51</sup></a> </p><p>Earth was very hostile to life before 4,300 to 4,200 Ma, and the conclusion is that before the Archean Eon, life as we know it would have been challenged by these environmental conditions. While life could have arisen before the Archean, the conditions necessary to sustain life could not have occurred until the Archean Eon.<a class="footnote-ref" id="fnref:52" href="#fn:52"><sup>52</sup></a> </p><p>Life in the Archean was limited to simple single-celled organisms (lacking nuclei), called <a href="/facts/Prokaryote/oYyvaDDH">prokaryotes</a>. In addition to the domain <a href="/facts/Bacteria/wC8xSCsU">Bacteria</a>, microfossils of the domain <a href="/facts/Archaea/Adxh0aHw">Archaea</a> have also been identified. There are no known <a href="/facts/Eukaryote/SkwyPLMA">eukaryotic</a> fossils from the earliest Archean, though they might have evolved during the Archean without leaving any.<a class="footnote-ref" id="fnref:53" href="#fn:53"><sup>53</sup></a>: 306, 323 Fossil <a href="/facts/Sterane/1MP9LfP2">steranes</a>, indicative of eukaryotes, have been reported from Archean strata but were shown to derive from contamination with younger organic matter.<a class="footnote-ref" id="fnref:54" href="#fn:54"><sup>54</sup></a> No fossil evidence has been discovered for <a href="/facts/Ultramicroscopic/D6ntoSgX">ultramicroscopic</a> <a href="/facts/Intracellular/UEPUhSN8">intracellular</a> replicators such as <a href="/facts/Virus/mf88Bcbl">viruses</a>. </p><p>Fossilized microbes from terrestrial microbial mats show that life was already established on land 3.22 billion years ago.<a class="footnote-ref" id="fnref:55" href="#fn:55"><sup>55</sup></a><a class="footnote-ref" id="fnref:56" href="#fn:56"><sup>56</sup></a> </p><p><i><a href="/facts/Thuchomyces/Rteo6YSa">Thuchomyces</a></i>, a Mesoarchean-Neoarchean fossil from South Africa, may be the first evidence of macroscopic land life, however it is likely a microbial mat due to a lack of eukaryotic features.<a class="footnote-ref" id="fnref:57" href="#fn:57"><sup>57</sup></a> </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Abiogenesis/BvAmLPQP">Abiogenesis</a> – Life arising from non-living matter</li> <li><a href="/facts/Cosmic_Calendar/NwD7cdEQ">Cosmic Calendar</a> – Method to visualize the chronology of the universe</li> <li><a href="/facts/Earliest_known_life_forms/5voHrbwL">Earliest known life forms</a> – Putative fossilized microorganisms found near hydrothermal vents</li> <li><a href="/facts/Geologic_time_scale/vBAm0D8Q">Geologic time scale</a> – System that relates geologic strata to time</li> <li><a href="/facts/Geological_history_of_oxygen/6VTugNzT">Geological history of oxygen</a></li> <li><a href="/facts/History_of_Earth/0aEAQF0k">History of Earth</a> – Overview of Earth's history</li> <li><a href="/facts/Precambrian/zjF3N3Rx">Precambrian</a> – History of Earth 4600–539 million years ago</li> <li><a href="/facts/Timeline_of_natural_history/7htqc31E">Timeline of natural history</a></li> <li><a href="/facts/Archean_felsic_volcanic_rocks/68LyDhnC">Archean felsic volcanic rocks</a> – Felsic volcanic rocks formed in the Archean Eon</li></ul> <h2 id="external-links">External links</h2> <ul><li><a href="https://web.archive.org/web/20100822004931/http://www.stratigraphy.org/bak/geowhen/stages/Archean.html">"Archean"</a>. GeoWhen Database. <i>stratigraphy.org</i>. Archived from <a href="http://www.stratigraphy.org/bak/geowhen/stages/Archean.html">the original</a> on 22 August 2010. Retrieved 17 September 2010.</li> <li><a href="http://www.utdallas.edu/~rjstern/PlateTectonicsStart/">"When did plate tectonics begin?"</a>. <i>utdallas.edu</i>. University of Texas – Dallas.</li> <li><a href="https://ghkclass.com/ghkC.html?archean">"Archean (chronostratigraphy scale)"</a>. <i>ghkclass.com</i>.</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Harper, Douglas. "Archaean". Online Etymology Dictionary. <a href="https://www.etymonline.com/word/Archaean" target="_blank">https://www.etymonline.com/word/Archaean</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>"Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 29 October 2023. <a href="https://stratigraphy.org/gssps/" target="_blank">https://stratigraphy.org/gssps/</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Galer, Stephen J. G.; Mezger, Klaus (1 December 1998). "Metamorphism, denudation and sea level in the Archean and cooling of the Earth". Precambrian Research. 92 (4): 389–412. Bibcode:1998PreR...92..389G. doi:10.1016/S0301-9268(98)00083-7. Retrieved 24 November 2022. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0301926898000837" target="_blank">https://www.sciencedirect.com/science/article/abs/pii/S0301926898000837</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Dostal J (2008). "Igneous Rock Associations 10. Komatiites". Geoscience Canada. 35 (1). <a href="https://journals.lib.unb.ca/index.php/GC/article/view/11074/11722" target="_blank">https://journals.lib.unb.ca/index.php/GC/article/view/11074/11722</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Cooper, John D.; Miller, Richard H.; Patterson, Jacqueline (1986). A Trip Through Time: Principles of historical geology. Columbus: Merrill Publishing Company. p. 180. ISBN 978-0675201407. <a href="978-0675201407" target="_blank">978-0675201407</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Stanley, Steven M. (1999). Earth System History. New York: W.H. Freeman and Company. ISBN 978-0716728825. <a href="978-0716728825" target="_blank">978-0716728825</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Korenaga, J (2021). "Was There Land on the Early Earth?". Life. 11 (11): 1142. Bibcode:2021Life...11.1142K. doi:10.3390/life11111142. PMC 8623345. PMID 34833018. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8623345" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8623345</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Korenaga, J (2021). "Hadean geodynamics and the nature of early continental crust". Precambrian Research. 359: 106178. Bibcode:2021PreR..35906178K. doi:10.1016/j.precamres.2021.106178. S2CID 233441822. <a href="/wiki/Precambrian_Research" target="_blank">/wiki/Precambrian_Research</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Korenaga, J (2021). "Was There Land on the Early Earth?". Life. 11 (11): 1142. Bibcode:2021Life...11.1142K. doi:10.3390/life11111142. PMC 8623345. PMID 34833018. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8623345" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8623345</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Bada, J. L.; Korenaga, J. (2018). "Exposed areas above sea level on Earth >3.5 Gyr ago: Implications for prebiotic and primitive biotic chemistry". Life. 8 (4): 55. Bibcode:2018Life....8...55B. doi:10.3390/life8040055. PMC 6316429. PMID 30400350. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316429" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316429</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Bindeman, I. N.; Zakharov, D. O.; Palandri, J.; Greber, N. D.; Dauphas, N.; Retallack, Gregory J.; Hofmann, A.; Lackey, J. S.; Bekker, A. (23 May 2018). "Rapid emergence of subaerial landmasses and onset of a modern hydrologic cycle 2.5 billion years ago". Nature. 557 (7706): 545–548. Bibcode:2018Natur.557..545B. doi:10.1038/s41586-018-0131-1. PMID 29795252. S2CID 43921922. Retrieved 25 December 2023. <a href="https://www.nature.com/articles/s41586-018-0131-1" target="_blank">https://www.nature.com/articles/s41586-018-0131-1</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Johnson, Benjamin W.; Wing, Boswell A. (2 March 2020). "Limited Archaean continental emergence reflected in an early Archaean 18O-enriched ocean". Nature Geoscience. 13 (3): 243–248. Bibcode:2020NatGe..13..243J. doi:10.1038/s41561-020-0538-9. ISSN 1752-0908. S2CID 211730235. Retrieved 25 December 2023. <a href="https://www.nature.com/articles/s41561-020-0538-9" target="_blank">https://www.nature.com/articles/s41561-020-0538-9</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Rogers JJ (1996). "A history of continents in the past three billion years". Journal of Geology. 104 (1): 91–107. Bibcode:1996JG....104...91R. doi:10.1086/629803. JSTOR 30068065. S2CID 128776432. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Cheney ES (1996). "Sequence stratigraphy and plate tectonic significance of the Transvaal succession of southern Africa and its equivalent in Western Australia". Precambrian Research. 79 (1–2): 3–24. Bibcode:1996PreR...79....3C. doi:10.1016/0301-9268(95)00085-2. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Korenaga, J (2021). "Was There Land on the Early Earth?". Life. 11 (11): 1142. Bibcode:2021Life...11.1142K. doi:10.3390/life11111142. PMC 8623345. PMID 34833018. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8623345" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8623345</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Marty, Bernard; Dauphas, Nicolas (15 February 2003). "The nitrogen record of crust–mantle interaction and mantle convection from Archean to Present". Earth and Planetary Science Letters. 206 (3–4): 397–410. Bibcode:2003E&PSL.206..397M. doi:10.1016/S0012-821X(02)01108-1. Retrieved 16 November 2022. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0012821X02011081" target="_blank">https://www.sciencedirect.com/science/article/abs/pii/S0012821X02011081</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Halla, Jaana; Van Hunen, Jeroen; Heilimo, Esa; Hölttä, Pentti (October 2009). "Geochemical and numerical constraints on Neoarchean plate tectonics". Precambrian Research. 174 (1–2): 155–162. Bibcode:2009PreR..174..155H. doi:10.1016/j.precamres.2009.07.008. Retrieved 12 November 2022. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0301926809001661#!" target="_blank">https://www.sciencedirect.com/science/article/abs/pii/S0301926809001661#!</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Borgeat, Xavier; Tackley, Paul J. (12 July 2022). "Hadean/Eoarchean tectonics and mantle mixing induced by impacts: a three-dimensional study". Progress in Earth and Planetary Science. 9 (1): 38. Bibcode:2022PEPS....9...38B. doi:10.1186/s40645-022-00497-0. hdl:20.500.11850/559385. S2CID 243973728. <a href="https://doi.org/10.1186%2Fs40645-022-00497-0" target="_blank">https://doi.org/10.1186%2Fs40645-022-00497-0</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Marchi, S.; Drabon, N.; Schulz, T.; Schaefer, L.; Nesvorny, D.; Bottke, W. F.; Koeberl, C.; Lyons, T. (November 2021). "Delayed and variable late Archaean atmospheric oxidation due to high collision rates on Earth". Nature Geoscience. 14 (11): 827–831. Bibcode:2021NatGe..14..827M. doi:10.1038/s41561-021-00835-9. S2CID 239055744. Retrieved 25 December 2023. <a href="https://www.nature.com/articles/s41561-021-00835-9" target="_blank">https://www.nature.com/articles/s41561-021-00835-9</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>Pavlov, A. A.; Kasting, J. F. (5 July 2004). "Mass-Independent Fractionation of Sulfur Isotopes in Archean Sediments: Strong Evidence for an Anoxic Archean Atmosphere". Astrobiology. 2 (1): 27–41. Bibcode:2002AsBio...2...27P. doi:10.1089/153110702753621321. PMID 12449853. Retrieved 12 November 2022. <a href="https://www.liebertpub.com/doi/abs/10.1089/153110702753621321" target="_blank">https://www.liebertpub.com/doi/abs/10.1089/153110702753621321</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></p></li> <li id="fn:21"><p>Zhang, Shuichang; Wang, Xiaomei; Wang, Huajian; Bjerrum, Christian J.; Hammarlund, Emma U.; Costa, M. Mafalda; Connelly, James N.; Zhang, Baomin; Su, Jin; Canfield, Donald Eugene (4 January 2016). "Sufficient oxygen for animal respiration 1,400 million years ago". Proceedings of the National Academy of Sciences of the United States of America. 113 (7): 1731–1736. Bibcode:2016PNAS..113.1731Z. doi:10.1073/pnas.1523449113. PMC 4763753. PMID 26729865. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4763753" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4763753</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></p></li> <li id="fn:22"><p>Laakso, T. A.; Schrag, D. P. (5 April 2017). "A theory of atmospheric oxygen". Geobiology. 15 (3): 366–384. Bibcode:2017Gbio...15..366L. doi:10.1111/gbi.12230. PMID 28378894. S2CID 22594748. Retrieved 12 November 2022. <a href="https://pubmed.ncbi.nlm.nih.gov/28378894/" target="_blank">https://pubmed.ncbi.nlm.nih.gov/28378894/</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></p></li> <li id="fn:23"><p>Crowe, Sean A.; Døssing, Lasse N.; Beukes, Nicolas J.; Bau, Michael; Kruger, Stephanus J.; Frei, Robert; Canfield, Donald Eugene (25 September 2013). "Atmospheric oxygenation three billion years ago". Nature. 501 (7468): 535–538. Bibcode:2013Natur.501..535C. doi:10.1038/nature12426. PMID 24067713. S2CID 4464710. Retrieved 12 November 2022. <a href="https://www.nature.com/articles/nature12426#citeas" target="_blank">https://www.nature.com/articles/nature12426#citeas</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></p></li> <li id="fn:24"><p>Large, Ross R.; Hazen, Robert M.; Morrison, Shaunna M.; Gregory, Dan D.; Steadman, Jeffrey A.; Mukherjee, Indrani (May 2022). "Evidence that the GOE was a prolonged event with a peak around 1900 Ma". Geosystems and Geoenvironment. 1 (2): 100036. Bibcode:2022GsGe....100036L. doi:10.1016/j.geogeo.2022.100036. S2CID 246755121. <a href="https://doi.org/10.1016%2Fj.geogeo.2022.100036" target="_blank">https://doi.org/10.1016%2Fj.geogeo.2022.100036</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></p></li> <li id="fn:25"><p>Anbar, Ariel D.; Duan, Yun; Lyons, Timothy W.; Arnold, Gail N.; Kendall, Brian; Creaser, Robert A.; Kaufman, Alan J.; Gordon, Gwyneth W.; Scott, Clinton; Garvin, Jessica; Buick, Roger (28 September 2007). "A Whiff of Oxygen Before the Great Oxidation Event?". Science. 317 (5846): 1903–1906. Bibcode:2007Sci...317.1903A. doi:10.1126/science.1140325. PMID 17901330. S2CID 25260892. Retrieved 12 November 2022. <a href="https://www.science.org/doi/10.1126/science.1140325" target="_blank">https://www.science.org/doi/10.1126/science.1140325</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></p></li> <li id="fn:26"><p>Reinhard, Christopher T.; Raiswell, Robert; Scott, Clinton; Anbar, Ariel D.; Lyons, Timothy W. (30 October 2009). "A Late Archean Sulfidic Sea Stimulated by Early Oxidative Weathering of the Continents". Science. 326 (5953): 713–716. Bibcode:2009Sci...326..713R. doi:10.1126/science.1176711. PMID 19900929. S2CID 25369788. Retrieved 12 November 2022. <a href="https://www.science.org/doi/10.1126/science.1176711" target="_blank">https://www.science.org/doi/10.1126/science.1176711</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></p></li> <li id="fn:27"><p>Large, Ross R.; Hazen, Robert M.; Morrison, Shaunna M.; Gregory, Dan D.; Steadman, Jeffrey A.; Mukherjee, Indrani (May 2022). "Evidence that the GOE was a prolonged event with a peak around 1900 Ma". Geosystems and Geoenvironment. 1 (2): 100036. Bibcode:2022GsGe....100036L. doi:10.1016/j.geogeo.2022.100036. S2CID 246755121. <a href="https://doi.org/10.1016%2Fj.geogeo.2022.100036" target="_blank">https://doi.org/10.1016%2Fj.geogeo.2022.100036</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></p></li> <li id="fn:28"><p>Warke, Matthew R.; Di Rocco, Tommaso; Zerkle, Aubrey L.; Lepland, Aivo; Prave, Anthony R.; Martin, Adam P.; Ueno, Yuichiro; Condon, Daniel J.; Claire, Mark W. (16 June 2020). "The Great Oxidation Event preceded a Paleoproterozoic "snowball Earth"". Proceedings of the National Academy of Sciences of the United States of America. 117 (24): 13314–13320. Bibcode:2020PNAS..11713314W. doi:10.1073/pnas.2003090117. ISSN 0027-8424. PMC 7306805. PMID 32482849. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7306805" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7306805</a> <a href="#fnref:28" class="footnote-back-ref">↩</a></p></li> <li id="fn:29"><p>Luo, Genming; Ono, Shuhei; Beukes, Nicolas J.; Wang, David T.; Xie, Shucheng; Summons, Roger E. (6 May 2016). "Rapid oxygenation of Earth's atmosphere 2.33 billion years ago". Science Advances. 2 (5): e1600134. Bibcode:2016SciA....2E0134L. doi:10.1126/sciadv.1600134. ISSN 2375-2548. PMC 4928975. PMID 27386544. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928975" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928975</a> <a href="#fnref:29" class="footnote-back-ref">↩</a></p></li> <li id="fn:30"><p>Poulton, Simon W.; Bekker, Andrey; Cumming, Vivien M.; Zerkle, Aubrey L.; Canfield, Donald E.; Johnston, David T. (April 2021). "A 200-million-year delay in permanent atmospheric oxygenation". Nature. 592 (7853): 232–236. Bibcode:2021Natur.592..232P. doi:10.1038/s41586-021-03393-7. hdl:10023/24041. ISSN 1476-4687. PMID 33782617. S2CID 232419035. Retrieved 7 January 2023. <a href="https://www.nature.com/articles/s41586-021-03393-7" target="_blank">https://www.nature.com/articles/s41586-021-03393-7</a> <a href="#fnref:30" class="footnote-back-ref">↩</a></p></li> <li id="fn:31"><p>Gumsley, Ashley P.; Chamberlain, Kevin R.; Bleeker, Wouter; Söderlund, Ulf; De Kock, Michiel O.; Larsson, Emilie R.; Bekker, Andrey (6 February 2017). "Timing and tempo of the Great Oxidation Event". Proceedings of the National Academy of Sciences of the United States of America. 114 (8): 1811–1816. Bibcode:2017PNAS..114.1811G. doi:10.1073/pnas.1608824114. ISSN 0027-8424. PMC 5338422. PMID 28167763. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5338422" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5338422</a> <a href="#fnref:31" class="footnote-back-ref">↩</a></p></li> <li id="fn:32"><p>Eickmann, Benjamin; Hofmann, Axel; Wille, Martin; Bui, Thi Hao; Wing, Boswell A.; Schoenberg, Ronny (15 January 2018). "Isotopic evidence for oxygenated Mesoarchaean shallow oceans". Nature Geoscience. 11 (2): 133–138. Bibcode:2018NatGe..11..133E. doi:10.1038/s41561-017-0036-x. S2CID 135023426. Retrieved 25 December 2022. <a href="https://www.nature.com/articles/s41561-017-0036-x?error=cookies_not_supported&code=54e99c94-9890-439d-a813-c26d056ce863" target="_blank">https://www.nature.com/articles/s41561-017-0036-x?error=cookies_not_supported&code=54e99c94-9890-439d-a813-c26d056ce863</a> <a href="#fnref:32" class="footnote-back-ref">↩</a></p></li> <li id="fn:33"><p>Zhou, Hang; Zhou, Wenxiao; Wei, Yunxu; Chi Fru, Ernest; Huang, Bo; Fu, Dong; Li, Haiquan; Tan, Mantang (December 2022). "Mesoarchean banded iron-formation from the northern Yangtze Craton, South China and its geological and paleoenvironmental implications". Precambrian Research. 383: 106905. Bibcode:2022PreR..38306905Z. doi:10.1016/j.precamres.2022.106905. Retrieved 17 December 2022. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0301926822003497" target="_blank">https://www.sciencedirect.com/science/article/abs/pii/S0301926822003497</a> <a href="#fnref:33" class="footnote-back-ref">↩</a></p></li> <li id="fn:34"><p>Fischer, W. W.; Schroeder, S.; Lacassie, J. P.; Beukes, N. J.; Goldberg, T.; Strauss, H.; Horstmann, U. E.; Schrag, D. P.; Knoll, A. H. (March 2009). "Isotopic constraints on the Late Archean carbon cycle from the Transvaal Supergroup along the western margin of the Kaapvaal Craton, South Africa". Precambrian Research. 169 (1–4): 15–27. Bibcode:2009PreR..169...15F. doi:10.1016/j.precamres.2008.10.010. Retrieved 24 November 2022. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0301926808002490" target="_blank">https://www.sciencedirect.com/science/article/abs/pii/S0301926808002490</a> <a href="#fnref:34" class="footnote-back-ref">↩</a></p></li> <li id="fn:35"><p>Fakhraee, Mojtaba; Katsev, Sergei (7 October 2019). "Organic sulfur was integral to the Archean sulfur cycle". Nature Communications. 10 (1): 4556. Bibcode:2019NatCo..10.4556F. doi:10.1038/s41467-019-12396-y. PMC 6779745. PMID 31591394. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6779745" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6779745</a> <a href="#fnref:35" class="footnote-back-ref">↩</a></p></li> <li id="fn:36"><p>Johnson, Benjamin W.; Wing, Boswell A. (2 March 2020). "Limited Archaean continental emergence reflected in an early Archaean 18O-enriched ocean". Nature Geoscience. 13 (3): 243–248. Bibcode:2020NatGe..13..243J. doi:10.1038/s41561-020-0538-9. S2CID 211730235. Retrieved 7 January 2023. <a href="https://www.nature.com/articles/s41561-020-0538-9?error=cookies_not_supported&code=bee768fe-63d9-40f0-9508-cddc3686d03a" target="_blank">https://www.nature.com/articles/s41561-020-0538-9?error=cookies_not_supported&code=bee768fe-63d9-40f0-9508-cddc3686d03a</a> <a href="#fnref:36" class="footnote-back-ref">↩</a></p></li> <li id="fn:37"><p>Dauphas, Nicolas; Kasting, James Fraser (1 June 2011). "Low pCO2 in the pore water, not in the Archean air". Nature. 474 (7349): E2-3, discussion E4-5. Bibcode:2011Natur.474E...1D. doi:10.1038/nature09960. PMID 21637211. S2CID 205224575. <a href="https://doi.org/10.1038%2Fnature09960" target="_blank">https://doi.org/10.1038%2Fnature09960</a> <a href="#fnref:37" class="footnote-back-ref">↩</a></p></li> <li id="fn:38"><p>Walker, James C. G. (November 1982). "Climatic factors on the Archean earth". Palaeogeography, Palaeoclimatology, Palaeoecology. 40 (1–3): 1–11. Bibcode:1982PPP....40....1W. doi:10.1016/0031-0182(82)90082-7. hdl:2027.42/23810. Retrieved 12 November 2022. <a href="https://www.sciencedirect.com/science/article/abs/pii/0031018282900827" target="_blank">https://www.sciencedirect.com/science/article/abs/pii/0031018282900827</a> <a href="#fnref:38" class="footnote-back-ref">↩</a></p></li> <li id="fn:39"><p>Walker, James C.G. (June 1985). "Carbon dioxide on the early earth" (PDF). Origins of Life and Evolution of Biospheres. 16 (2): 117–127. Bibcode:1985OrLi...16..117W. doi:10.1007/BF01809466. hdl:2027.42/43349. PMID 11542014. S2CID 206804461. Retrieved 30 January 2010. <a href="http://deepblue.lib.umich.edu/bitstream/2027.42/43349/1/11084_2005_Article_BF01809466.pdf" target="_blank">http://deepblue.lib.umich.edu/bitstream/2027.42/43349/1/11084_2005_Article_BF01809466.pdf</a> <a href="#fnref:39" class="footnote-back-ref">↩</a></p></li> <li id="fn:40"><p>Pavlov AA, Kasting JF, Brown LL, Rages KA, Freedman R (May 2000). "Greenhouse warming by CH4 in the atmosphere of early Earth". Journal of Geophysical Research. 105 (E5): 11981–11990. Bibcode:2000JGR...10511981P. doi:10.1029/1999JE001134. PMID 11543544. <a href="https://doi.org/10.1029%2F1999JE001134" target="_blank">https://doi.org/10.1029%2F1999JE001134</a> <a href="#fnref:40" class="footnote-back-ref">↩</a></p></li> <li id="fn:41"><p>Buessecker, Steffen; Imanaka, Hiroshi; Ely, Tucker; Hu, Renyu; Romaniello, Stephen J.; Cadillo-Quiroz, Hinsby (5 December 2022). "Mineral-catalysed formation of marine NO and N2O on the anoxic early Earth". Nature Geoscience. 15 (1): 1056–1063. Bibcode:2022NatGe..15.1056B. doi:10.1038/s41561-022-01089-9. S2CID 254276951. Retrieved 28 April 2023. <a href="https://www.nature.com/articles/s41561-022-01089-9" target="_blank">https://www.nature.com/articles/s41561-022-01089-9</a> <a href="#fnref:41" class="footnote-back-ref">↩</a></p></li> <li id="fn:42"><p>Rosing MT, Bird DK, Sleep NH, Bjerrum CJ (April 2010). "No climate paradox under the faint early Sun". Nature. 464 (7289): 744–747. Bibcode:2010Natur.464..744R. doi:10.1038/nature08955. PMID 20360739. S2CID 205220182. <a href="/wiki/Nature_(journal)" target="_blank">/wiki/Nature_(journal)</a> <a href="#fnref:42" class="footnote-back-ref">↩</a></p></li> <li id="fn:43"><p>Ohtomo Y, Kakegawa T, Ishida A, Nagase T, Rosing MT (8 December 2013). "Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks". Nature Geoscience. 7 (1): 25–28. Bibcode:2014NatGe...7...25O. doi:10.1038/ngeo2025. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:43" class="footnote-back-ref">↩</a></p></li> <li id="fn:44"><p>Borenstein, Seth (13 November 2013). "Oldest fossil found: Meet your microbial mom". AP News. Retrieved 15 November 2013. <a href="http://apnews.excite.com/article/20131113/DAA1VSC01.html" target="_blank">http://apnews.excite.com/article/20131113/DAA1VSC01.html</a> <a href="#fnref:44" class="footnote-back-ref">↩</a></p></li> <li id="fn:45"><p>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): 1103–1124. Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. PMC 3870916. PMID 24205812. <a href="/wiki/Nora_Noffke" target="_blank">/wiki/Nora_Noffke</a> <a href="#fnref:45" class="footnote-back-ref">↩</a></p></li> <li id="fn:46"><p>Garwood, Russell J. (2012). "Patterns In Palaeontology: The first 3 billion years of evolution". Palaeontology Online. 2 (11): 1–14. Retrieved 25 June 2015. <a href="http://www.palaeontologyonline.com/articles/2012/patterns-in-palaeontology-the-first-3-billion-years-of-evolution/" target="_blank">http://www.palaeontologyonline.com/articles/2012/patterns-in-palaeontology-the-first-3-billion-years-of-evolution/</a> <a href="#fnref:46" class="footnote-back-ref">↩</a></p></li> <li id="fn:47"><p>Stanley, Steven M. (1999). Earth System History. New York: W.H. Freeman and Company. ISBN 978-0716728825. <a href="978-0716728825" target="_blank">978-0716728825</a> <a href="#fnref:47" class="footnote-back-ref">↩</a></p></li> <li id="fn:48"><p>Shen Y, Buick R, Canfield DE (March 2001). "Isotopic evidence for microbial sulphate reduction in the early Archaean era". Nature. 410 (6824): 77–81. Bibcode:2001Natur.410...77S. doi:10.1038/35065071. PMID 11242044. S2CID 25375808. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:48" class="footnote-back-ref">↩</a></p></li> <li id="fn:49"><p>Seal RR (2006). "Sulfur isotope geochemistry of sulfide minerals". Reviews in Mineralogy and Geochemistry. 61 (1): 633–677. Bibcode:2006RvMG...61..633S. doi:10.2138/rmg.2006.61.12. <a href="http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1354&context=usgsstaffpub" target="_blank">http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1354&context=usgsstaffpub</a> <a href="#fnref:49" class="footnote-back-ref">↩</a></p></li> <li id="fn:50"><p>Borenstein, Seth (19 October 2015). "Hints of life on what was thought to be desolate early Earth". Excite. Yonkers, NY: Mindspark Interactive Network. Associated Press. Retrieved 20 October 2015. <a href="http://apnews.excite.com/article/20151019/us-sci--earliest_life-a400435d0d.html" target="_blank">http://apnews.excite.com/article/20151019/us-sci--earliest_life-a400435d0d.html</a> <a href="#fnref:50" class="footnote-back-ref">↩</a></p></li> <li id="fn:51"><p>Bell EA, Boehnke P, Harrison TM, Mao WL (November 2015). "Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon". Proceedings of the National Academy of Sciences of the United States of America. 112 (47) (Early, published online before print ed.): 14518–14521. Bibcode:2015PNAS..11214518B. doi:10.1073/pnas.1517557112. PMC 4664351. PMID 26483481. <a href="/wiki/Wendy_Mao" target="_blank">/wiki/Wendy_Mao</a> <a href="#fnref:51" class="footnote-back-ref">↩</a></p></li> <li id="fn:52"><p>Nisbet, Euan (1980). "Archaean stromatolites and the search for the earliest life". Nature. 284 (5755): 395–396. Bibcode:1980Natur.284..395N. doi:10.1038/284395a0. S2CID 4262249. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:52" class="footnote-back-ref">↩</a></p></li> <li id="fn:53"><p>Stanley, Steven M. (1999). Earth System History. New York: W.H. Freeman and Company. ISBN 978-0716728825. <a href="978-0716728825" target="_blank">978-0716728825</a> <a href="#fnref:53" class="footnote-back-ref">↩</a></p></li> <li id="fn:54"><p>French KL, Hallmann C, Hope JM, Schoon PL, Zumberge JA, Hoshino Y, Peters CA, George SC, Love GD, Brocks JJ, Buick R, Summons RE (May 2015). "Reappraisal of hydrocarbon biomarkers in Archean rocks". Proceedings of the National Academy of Sciences of the United States of America. 112 (19): 5915–5920. Bibcode:2015PNAS..112.5915F. doi:10.1073/pnas.1419563112. PMC 4434754. PMID 25918387. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434754" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434754</a> <a href="#fnref:54" class="footnote-back-ref">↩</a></p></li> <li id="fn:55"><p>Homann, Martin; Sansjofre, Pierre; Van Zuilen, Mark; Heubeck, Christoph; Gong, Jian; Killingsworth, Bryan; Foster, Ian S.; Airo, Alessandro; Van Kranendonk, Martin J.; Ader, Magali; Lalonde, Stefan V. (23 July 2018). "Microbial life and biogeochemical cycling on land 3,220 million years ago". Nature Geoscience. 11 (9): 665–671. Bibcode:2018NatGe..11..665H. doi:10.1038/s41561-018-0190-9. S2CID 134935568. Retrieved 14 January 2023. <a href="https://www.nature.com/articles/s41561-018-0190-9?error=cookies_not_supported&code=de9a5c60-153f-4b56-a4d4-e0ae6ad9222d" target="_blank">https://www.nature.com/articles/s41561-018-0190-9?error=cookies_not_supported&code=de9a5c60-153f-4b56-a4d4-e0ae6ad9222d</a> <a href="#fnref:55" class="footnote-back-ref">↩</a></p></li> <li id="fn:56"><p>Woo, Marcus (30 July 2018). "Oldest Evidence for life on land unearthed in South Africa". Live Science. <a href="https://www.livescience.com/63199-oldest-life-on-land.html" target="_blank">https://www.livescience.com/63199-oldest-life-on-land.html</a> <a href="#fnref:56" class="footnote-back-ref">↩</a></p></li> <li id="fn:57"><p>Lücking, Robert; Nelsen, Matthew P. (2018). "Ediacarans, Protolichens, and Lichen-Derived Penicillium". Transformative Paleobotany: 551–590. doi:10.1016/B978-0-12-813012-4.00023-1. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:57" class="footnote-back-ref">↩</a></p></li> </ol>