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window.loswp.translateUrl = "https://www.academia.edu/login?post_login_redirect_url=https%3A%2F%2Fwww.academia.edu%2F12356176%2FEvidence_from_detrital_zircons_for_the_existence_of_continental_crust_and_oceans_on_the_Earth_4_4_Gyr_ago%3Fshow_translation%3Dtrue"; window.loswp.previewableAttachments = [{"id":46225760,"identifier":"Attachment_46225760","shouldShowBulkDownload":false}]; window.loswp.shouldDetectTimezone = true; window.loswp.shouldShowBulkDownload = true; window.loswp.showSignupCaptcha = false window.loswp.willEdgeCache = false; window.loswp.work = {"work":{"id":12356176,"created_at":"2015-05-12T12:53:08.801-07:00","from_world_paper_id":136311488,"updated_at":"2024-12-04T08:31:33.180-08:00","_data":{"ai_abstract":"No crustal rocks are known to have survived since the time of the intense meteor bombardment that affected Earth between its formation and 4,030 Myr ago; however, detrital zircons found at Jack Hills, Australia, provide evidence of continental crust and oceans existing as far back as 4.4 Gyr ago. Detailed analysis of these zircons reveals unique zoning in respect to rare earth elements and oxygen isotopes, suggesting formation from a granitic melt and indicating interactions with an ancient hydrosphere. This finding marks the earliest definitive evidence for continental crust and oceans on Earth, extending our understanding of the planet's early geological history.","publication_date":"2001,,"},"document_type":"paper","pre_hit_view_count_baseline":null,"quality":"high","language":"en","title":"Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago","broadcastable":true,"draft":null,"has_indexable_attachment":true,"indexable":true}}["work"]; window.loswp.workCoauthors = [55204412,31054590]; window.loswp.locale = "en"; window.loswp.countryCode = "SG"; window.loswp.cwvAbTestBucket = ""; window.loswp.designVariant = "ds_vanilla"; window.loswp.fullPageMobileSutdModalVariant = "control"; window.loswp.useOptimizedScribd4genScript = false; window.loginModal = {}; window.loginModal.appleClientId = 'edu.academia.applesignon'; window.userInChina = "false";</script><script defer="" src="https://accounts.google.com/gsi/client"></script><div class="ds-loswp-container"><div class="ds-work-card--grid-container"><div class="ds-work-card--container js-loswp-work-card"><div class="ds-work-card--cover"><div class="ds-work-cover--wrapper"><div class="ds-work-cover--container"><button class="ds-work-cover--clickable js-swp-download-button" data-signup-modal="{"location":"swp-splash-paper-cover","attachmentId":46225760,"attachmentType":"pdf"}"><img alt="First page of “Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago”" class="ds-work-cover--cover-thumbnail" src="https://0.academia-photos.com/attachment_thumbnails/46225760/mini_magick20190210-12824-1vtc1tg.png?1549810176" /><img alt="PDF Icon" class="ds-work-cover--file-icon" src="//a.academia-assets.com/images/single_work_splash/adobe_icon.svg" /><div class="ds-work-cover--hover-container"><span class="material-symbols-outlined" style="font-size: 20px" translate="no">download</span><p>Download Free PDF</p></div><div class="ds-work-cover--ribbon-container">Download Free PDF</div><div class="ds-work-cover--ribbon-triangle"></div></button></div></div></div><div class="ds-work-card--work-information"><h1 class="ds-work-card--work-title">Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago</h1><div class="ds-work-card--work-authors ds-work-card--detail"><a class="ds-work-card--author js-wsj-grid-card-author ds2-5-body-md ds2-5-body-link" data-author-id="55204412" href="https://independent.academia.edu/WilliamPeck2"><img alt="Profile image of William Peck" class="ds-work-card--author-avatar" src="https://0.academia-photos.com/55204412/14847312/15631715/s65_william.peck.jpg" />William Peck</a><a class="ds-work-card--author js-wsj-grid-card-author ds2-5-body-md ds2-5-body-link" data-author-id="31054590" href="https://wisc.academia.edu/JohnValley"><img alt="Profile image of John Valley" class="ds-work-card--author-avatar" src="https://0.academia-photos.com/31054590/9107827/10158297/s65_john.valley.jpg" />John Valley</a></div><div class="ds-work-card--detail"><p class="ds-work-card--detail ds2-5-body-sm">2001</p><div class="ds-work-card--work-metadata"><div class="ds-work-card--work-metadata__stat"><span class="material-symbols-outlined" style="font-size: 20px" translate="no">visibility</span><p class="ds2-5-body-sm" id="work-metadata-view-count">…</p></div><div class="ds-work-card--work-metadata__stat"><span class="material-symbols-outlined" style="font-size: 20px" translate="no">description</span><p class="ds2-5-body-sm">4 pages</p></div><div class="ds-work-card--work-metadata__stat"><span class="material-symbols-outlined" style="font-size: 20px" translate="no">link</span><p class="ds2-5-body-sm">1 file</p></div></div><script>(async () => { const workId = 12356176; 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if (!viewCountBody) { throw new Error('Failed to find work views element'); } viewCountBody.textContent = `${commaizedViewCount} views`; } catch (error) { // Remove the whole views element if there was some issue parsing. document.getElementById('work-metadata-view-count')?.parentNode?.remove(); throw new Error(`Failed to parse view count: ${viewCount}`, error); } }; // If the DOM is still loading, wait for it to be ready before updating the view count. if (document.readyState === "loading") { document.addEventListener('DOMContentLoaded', () => { updateViewCount(viewCount); }); // Otherwise, just update it immediately. } else { updateViewCount(viewCount); } })();</script></div><p class="ds-work-card--detail ds2-5-body-md">AI-generated Abstract</p><p class="ds-work-card--work-abstract ds-work-card--detail ds2-5-body-md">No crustal rocks are known to have survived since the time of the intense meteor bombardment that affected Earth between its formation and 4,030 Myr ago; however, detrital zircons found at Jack Hills, Australia, provide evidence of continental crust and oceans existing as far back as 4.4 Gyr ago. Detailed analysis of these zircons reveals unique zoning in respect to rare earth elements and oxygen isotopes, suggesting formation from a granitic melt and indicating interactions with an ancient hydrosphere. This finding marks the earliest definitive evidence for continental crust and oceans on Earth, extending our understanding of the planet's early geological history.</p><div class="ds-work-card--button-container"><button class="ds2-5-button js-swp-download-button" data-signup-modal="{"location":"continue-reading-button--work-card","attachmentId":46225760,"attachmentType":"pdf","workUrl":"https://www.academia.edu/12356176/Evidence_from_detrital_zircons_for_the_existence_of_continental_crust_and_oceans_on_the_Earth_4_4_Gyr_ago"}">See full PDF</button><button class="ds2-5-button ds2-5-button--secondary js-swp-download-button" data-signup-modal="{"location":"download-pdf-button--work-card","attachmentId":46225760,"attachmentType":"pdf","workUrl":"https://www.academia.edu/12356176/Evidence_from_detrital_zircons_for_the_existence_of_continental_crust_and_oceans_on_the_Earth_4_4_Gyr_ago"}"><span class="material-symbols-outlined" style="font-size: 20px" translate="no">download</span>Download PDF</button></div><div class="ds-signup-banner-trigger-container"><div class="ds-signup-banner-trigger ds-signup-banner-trigger-control"></div></div><div class="ds-signup-banner ds-signup-banner-control"><div id="ds-signup-banner-close-button"><button class="ds2-5-button ds2-5-button--secondary ds2-5-button--inverse"><span class="material-symbols-outlined" style="font-size: 20px" translate="no">close</span></button></div><div class="ds-signup-banner-ctas"><img src="//a.academia-assets.com/images/academia-logo-capital-white.svg" /><h4 class="ds2-5-heading-serif-sm">Sign up for access to the world's latest research</h4><button class="ds2-5-button ds2-5-button--inverse ds2-5-button--full-width js-swp-download-button" data-signup-modal="{"location":"signup-banner"}">Sign up for free<span class="material-symbols-outlined" style="font-size: 20px" translate="no">arrow_forward</span></button></div><div class="ds-signup-banner-divider"></div><div class="ds-signup-banner-reasons"><div class="ds-signup-banner-reasons-item"><span class="material-symbols-outlined" style="font-size: 24px" translate="no">check</span><span>Get notified about relevant papers</span></div><div class="ds-signup-banner-reasons-item"><span class="material-symbols-outlined" style="font-size: 24px" translate="no">check</span><span>Save papers to use in your research</span></div><div class="ds-signup-banner-reasons-item"><span class="material-symbols-outlined" style="font-size: 24px" translate="no">check</span><span>Join the discussion with peers</span></div><div class="ds-signup-banner-reasons-item"><span class="material-symbols-outlined" style="font-size: 24px" translate="no">check</span><span>Track your impact</span></div></div></div><script>(() => { // Set up signup banner show/hide behavior: // 1. 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Rare >4000 Ma detrital zircons from Western Australia preserve the only direct geologic evidence of this early magmatism. To understand the genesis and history of these zircons, we present the results of a combined ion and electron microprobe, and SEM study of the age, Th-U chemistry, cathodoluminescence (CL) zoning patterns, and inclusions for a population of detrital zircons from Jack Hills, Western Australia, with 207 Pb/ 206 Pb ages ranging from 4348 to 1576 Ma. The majority of the zircons preserve primary growth features discernable by CL imaging, such as oscillatory and sector zoning, have Th/U ratios from 0.1 to 1.0, and several contain granitic mineral inclusions. Thus, aside from age they are largely indistinguishable from zircons produced in common felsic magmas. The Jack Hills zircons are therefore remnants of igneous rock-forming events that pre-date the rock record by up to 400 Ma. The 207 Pb/ 206 Pb age distribution pattern for zircons older than 3800 Ma from Western Australia suggests that early Archean magmatism was punctuated, both in terms of high frequency events and conspicuous gaps. The variable age distributions within different rock units in the Jack Hills demonstrate that Early Archean zircons were derived from multiple source rocks; samples from Eranondoo Hill contain up to 12% >4000 Ma zircons, suggesting either that the source rocks were nearby or represent a large terrane. Furthermore, younger 3700-3400 Ma rims on 4300-4000 Ma zircons are evidence that >4000 Ma crust survived long enough to participate in younger Archean tectonic events in the Yilgarn Craton of Western Australia. Mesoproterozoic igneous zircons in a quartzite 50 m from Eranondoo Hill are attributed to either sedimentation or tectonic interleaving of younger sediments no earlier than 1576 Ma. This previously unrecognized Proterozoic (or younger) geologic history calls into question previous estimates of the age of the Jack Hills sediments and demonstrates the heterogeneous distribution of >4000 Ma grains within the belt.</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Internal zoning and U��Th��Pb chemistry of Jack Hills detrital zircons: a mineral record of early Archean to Mesoproterozoic (4348��1576Ma) magmatism","attachmentId":46225734,"attachmentType":"pdf","work_url":"https://www.academia.edu/12356200/Internal_zoning_and_U_Th_Pb_chemistry_of_Jack_Hills_detrital_zircons_a_mineral_record_of_early_Archean_to_Mesoproterozoic_4348_1576Ma_magmatism","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/12356200/Internal_zoning_and_U_Th_Pb_chemistry_of_Jack_Hills_detrital_zircons_a_mineral_record_of_early_Archean_to_Mesoproterozoic_4348_1576Ma_magmatism"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="1" data-entity-id="12356181" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/12356181/Oxygen_isotope_ratios_and_rare_earth_elements_in_3_3_to_4_4_Ga_zircons_Ion_microprobe_evidence_for_high_sup_18_sup_O_continental_crust_and_oceans_in_the_Early_Archean">Oxygen isotope ratios and rare earth elements in 3.3 to 4.4 Ga zircons: Ion microprobe evidence for high ��< sup> 18</sup> O continental crust and oceans in the Early Archean</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="32816813" href="https://curtin.academia.edu/SimonWilde">Simon A Wilde</a><span>, </span><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="5479732" href="https://colgate.academia.edu/WilliamPeck">William Peck</a><span>, </span><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="31054590" href="https://wisc.academia.edu/JohnValley">John Valley</a></div><p class="ds-related-work--metadata ds2-5-body-xs">2001</p><p class="ds-related-work--abstract ds2-5-body-sm">Ion microprobe analyses of oxygen isotope ratios in Early Archean (Hadean) zircons (4.0-to 4.4-Ga) reveal variable magmatic ␦ 18 O values, including some that are high relative to the mantle, suggesting interaction between magmas and already-formed continental crust during the first 500 million yr of Earth's history. The high average ␦ 18 O value of these zircons is confirmed by conventional analysis. A metaconglomerate from the Jack Hills in the Yilgarn Craton (Western Australia) contains detrital zircons with ages Ͼ 4.0 Ga (Compston and Pidgeon, 1986) and one crystal that is 4.40-Ga old . The newly discovered 4.40-Ga grain is the oldest recognized terrestrial mineral. The Jack Hills metaconglomerate also contains a large 3.3-to 3.6-Ga-old zircon population with an average ␦ 18 O value of 6.3 Ϯ 0.1‰ (1 s.e., ; n ϭ 32 spot analyses). Two 4.15-Ga zircons have an average ␦ 18 O of 5.7 Ϯ 0.2‰ (n ϭ 13). In addition, a 4.13-Ga zircon has an average ␦ 18 O of 7.2 Ϯ 0.3‰ (n ϭ 8) and another 4.01-Ga zircon has an average ␦ 18 O of 6.8 Ϯ 0.4‰ (n ϭ 10). The oldest grain (4.40 Ga) is zoned with respect trace element composition (especially LREE), and intensity of cathodoluminescence, all of which correlate with oxygen isotope ratios (7.4‰ vs. 5.0‰). High LREE and high-␦ 18 O values from the 4.01-to 4.40-Ga grains are consistent with growth in evolved granitic magmas (␦ 18 O(WR) ϭ 8.5 to 9.5‰) that had interacted with supracrustal materials. High ␦ 18 O values show that low-temperature surficial processes (i.e., diagenesis, weathering, or low-temperature alteration) occurred before 4.0 Ga, and even before 4.40 Ga, shortly following the hypothesized date of core differentiation and impact of a Mars-sized body to form the Moon at ϳ4.45 Ga. This is the first evidence of continental crust as early as 4.40 Ga and suggests differentiation during the period of intense meteorite bombardment of the early Earth. The magnitude of water and rock interaction that would be necessary to cause the high ␦ 18 O values suggests the presence of liquid water and thus the possibility of an ocean at 4.40 Ga.</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Oxygen isotope ratios and rare earth elements in 3.3 to 4.4 Ga zircons: Ion microprobe evidence for high ��\u003c sup\u003e 18\u003c/sup\u003e O continental crust and oceans in the Early Archean","attachmentId":46225761,"attachmentType":"pdf","work_url":"https://www.academia.edu/12356181/Oxygen_isotope_ratios_and_rare_earth_elements_in_3_3_to_4_4_Ga_zircons_Ion_microprobe_evidence_for_high_sup_18_sup_O_continental_crust_and_oceans_in_the_Early_Archean","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/12356181/Oxygen_isotope_ratios_and_rare_earth_elements_in_3_3_to_4_4_Ga_zircons_Ion_microprobe_evidence_for_high_sup_18_sup_O_continental_crust_and_oceans_in_the_Early_Archean"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="2" data-entity-id="3664421" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/3664421/Single_zircon_dating_by_stepwise_Pb_evaporation_constrains_the_Archean_history_of_detrital_zircons_from_the_Jack_Hills_Western_Australia">Single-zircon dating by stepwise Pb-evaporation constrains the Archean history of detrital zircons from the Jack Hills, Western Australia</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="38935852" href="https://independent.academia.edu/PidgeonR">R. Pidgeon</a><span>, </span><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="3302080" href="https://uni-heidelberg.academia.edu/BerndKober">Bernd Kober</a></div><p class="ds-related-work--metadata ds2-5-body-xs">Earth and Planetary Science Letters, 1989</p><p class="ds-related-work--abstract ds2-5-body-sm">Pb isotope analyses have been carried out on 42 zircon grains from a Western Australian metaconglomerate using stepwise Pb-evaporation directly in the ion source of a thermal ionization mass spectrometer. The metaconglomerate is from the Archean Jack Hills Metasedimentary Belt, and is known from ion microprobe (“SHRIMP”) analyses to contain a complex zircon population with ages between 4.2 Ga and 3.1 Ga. The same complex pattern of ages is found by the Pb evaporation studies. Five grains yielded minimum crystallization ages from 4.17 Ga to 4.07 Ga. The main population appears significantly younger, having been generated at about 3.55-3.3 Ga. The agreement between the two analytical approaches confirms the SHRIMP results and demonstrates the value of the stepwise-evaporation technique in determining the age patterns of mixed zircon populations.In many of the evaporative Pb isotope records the 207/206 ratios remained constant for all evaporation steps, which we interpret as evaporation from concordant zircon phases. However, for the majority of zircons 207/206 ratios increased with increasing evaporation temperature, and usually approached constant values during evaporation at the highest temperatures. This can be attributed to mixing of different radiogenic Pb components from either crystalline zircon phases of different ages or from domains of isotopically disturbed metamict zircon.Present results confirm > 4 Ga zircon ages in the metaconglomerate from the Jack Hills and substantiate formation of crust at a very early stage in the evolution of the earth. Results also confirm a major crust-forming event 3.55-3.3 Ga ago.</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Single-zircon dating by stepwise Pb-evaporation constrains the Archean history of detrital zircons from the Jack Hills, Western Australia","attachmentId":50185958,"attachmentType":"pdf","work_url":"https://www.academia.edu/3664421/Single_zircon_dating_by_stepwise_Pb_evaporation_constrains_the_Archean_history_of_detrital_zircons_from_the_Jack_Hills_Western_Australia","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/3664421/Single_zircon_dating_by_stepwise_Pb_evaporation_constrains_the_Archean_history_of_detrital_zircons_from_the_Jack_Hills_Western_Australia"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="3" data-entity-id="51363402" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/51363402/Trace_element_chemistry_of_zircons_from_oceanic_crust_A_method_for_distinguishing_detrital_zircon_provenance">Trace element chemistry of zircons from oceanic crust: A method for distinguishing detrital zircon provenance</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="185323663" href="https://independent.academia.edu/JosephWooden1">Joseph Wooden</a></div><p class="ds-related-work--metadata ds2-5-body-xs">Geology, 2007</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Trace element chemistry of zircons from oceanic crust: A method for distinguishing detrital zircon provenance","attachmentId":69119156,"attachmentType":"pdf","work_url":"https://www.academia.edu/51363402/Trace_element_chemistry_of_zircons_from_oceanic_crust_A_method_for_distinguishing_detrital_zircon_provenance","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/51363402/Trace_element_chemistry_of_zircons_from_oceanic_crust_A_method_for_distinguishing_detrital_zircon_provenance"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="4" data-entity-id="7935010" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/7935010/On_the_occurrence_trace_element_geochemistry_and_crystallization_history_of_zircon_from_in_situ_ocean_lithosphere">On the occurrence, trace element geochemistry, and crystallization history of zircon from in situ ocean lithosphere</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="15084657" href="https://independent.academia.edu/RayStoeser">Ray Stoeser</a></div><p class="ds-related-work--metadata ds2-5-body-xs">Contributions To Mineralogy and Petrology, 2009</p><p class="ds-related-work--abstract ds2-5-body-sm">We characterize the textural and geochemical features of ocean crustal zircon recovered from plagiogranite, evolved gabbro, and metamorphosed ultramafic hostrocks collected along present-day slow and ultraslow spreading mid-ocean ridges (MORs). The geochemistry of 267 zircon grains was measured by sensitive high-resolution ion microprobe-reverse geometry at the USGS-Stanford Ion Microprobe facility. Three types of zircon are recognized based on texture and geochemistry. Most ocean crustal zircons resemble young magmatic zircon from other crustal settings, occurring as pristine, colorless euhedral (Type 1) or subhedral to anhedral (Type 2) grains. In these grains, Hf and most trace elements vary systematically with Ti, typically becoming enriched with falling Ti-in-zircon temperature. Ti-in-zircon temperatures range from 1,040 to 660°C (corrected for a TiO2 & 0.7, a SiO2 & 1.0, pressure & 2 kbar); intra-sample variation is typically *60-150°C. Decreasing Ti correlates with enrichment in Hf to *2 wt%, while additional Hf-enrichment occurs at relatively constant temperature. Trends between Ti and U, Y, REE, and Eu/Eu* exhibit a similar inflection, which may denote the onset of eutectic crystallization; the inflection is well-defined by zircons from plagiogranite and implies solidus temperatures of *680-740°C. A third type of zircon is defined as being porous and colored with chaotic CL zoning, and occurs in *25% of rock samples studied. These features, along with high measured La, Cl, S, Ca, and Fe, and low (Sm/La) N ratios are suggestive of interaction with aqueous fluids. Non-porous, luminescent CL overgrowth rims on porous grains record uniform temperatures averaging 615 ± 26°C (2SD, n = 7), implying zircon formation below the wet-granite solidus and under water-saturated conditions. Zircon geochemistry reflects, in part, source region; elevated HREE coupled with low U concentrations allow effective discrimination of *80% of zircon formed at modern MORs from zircon in continental crust. The geochemistry and textural observations reported here serve as an important database for comparison with detrital, xenocrystic, and metamorphosed mafic rock-hosted zircon populations to evaluate provenance.</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"On the occurrence, trace element geochemistry, and crystallization history of zircon from in situ ocean lithosphere","attachmentId":48285224,"attachmentType":"pdf","work_url":"https://www.academia.edu/7935010/On_the_occurrence_trace_element_geochemistry_and_crystallization_history_of_zircon_from_in_situ_ocean_lithosphere","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/7935010/On_the_occurrence_trace_element_geochemistry_and_crystallization_history_of_zircon_from_in_situ_ocean_lithosphere"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="5" data-entity-id="24604346" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/24604346/Oxygen_isotope_ratios_and_rare_earth_elements_in_3_3_to_4_4_Ga_zircons_Ion_microprobe_evidence_for_high_%CE%B418O_continental_crust_and_oceans_in_the_Early_Archean">Oxygen isotope ratios and rare earth elements in 3.3 to 4.4 Ga zircons: Ion microprobe evidence for high δ18O continental crust and oceans in the Early Archean</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="30027441" href="https://independent.academia.edu/ColinGraham2">Colin Graham</a></div><p class="ds-related-work--metadata ds2-5-body-xs">Geochimica et Cosmochimica Acta, 2001</p><p class="ds-related-work--abstract ds2-5-body-sm">Ion microprobe analyses of oxygen isotope ratios in Early Archean (Hadean) zircons (4.0-to 4.4-Ga) reveal variable magmatic ␦ 18 O values, including some that are high relative to the mantle, suggesting interaction between magmas and already-formed continental crust during the first 500 million yr of Earth's history. The high average ␦ 18 O value of these zircons is confirmed by conventional analysis. A metaconglomerate from the Jack Hills in the Yilgarn Craton (Western Australia) contains detrital zircons with ages Ͼ 4.0 Ga (Compston and Pidgeon, 1986) and one crystal that is 4.40-Ga old . The newly discovered 4.40-Ga grain is the oldest recognized terrestrial mineral. The Jack Hills metaconglomerate also contains a large 3.3-to 3.6-Ga-old zircon population with an average ␦ 18 O value of 6.3 Ϯ 0.1‰ (1 s.e., ; n ϭ 32 spot analyses). Two 4.15-Ga zircons have an average ␦ 18 O of 5.7 Ϯ 0.2‰ (n ϭ 13). In addition, a 4.13-Ga zircon has an average ␦ 18 O of 7.2 Ϯ 0.3‰ (n ϭ 8) and another 4.01-Ga zircon has an average ␦ 18 O of 6.8 Ϯ 0.4‰ (n ϭ 10). The oldest grain (4.40 Ga) is zoned with respect trace element composition (especially LREE), and intensity of cathodoluminescence, all of which correlate with oxygen isotope ratios (7.4‰ vs. 5.0‰). High LREE and high-␦ 18 O values from the 4.01-to 4.40-Ga grains are consistent with growth in evolved granitic magmas (␦ 18 O(WR) ϭ 8.5 to 9.5‰) that had interacted with supracrustal materials. High ␦ 18 O values show that low-temperature surficial processes (i.e., diagenesis, weathering, or low-temperature alteration) occurred before 4.0 Ga, and even before 4.40 Ga, shortly following the hypothesized date of core differentiation and impact of a Mars-sized body to form the Moon at ϳ4.45 Ga. This is the first evidence of continental crust as early as 4.40 Ga and suggests differentiation during the period of intense meteorite bombardment of the early Earth. The magnitude of water and rock interaction that would be necessary to cause the high ␦ 18 O values suggests the presence of liquid water and thus the possibility of an ocean at 4.40 Ga.</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Oxygen isotope ratios and rare earth elements in 3.3 to 4.4 Ga zircons: Ion microprobe evidence for high δ18O continental crust and oceans in the Early Archean","attachmentId":44933870,"attachmentType":"pdf","work_url":"https://www.academia.edu/24604346/Oxygen_isotope_ratios_and_rare_earth_elements_in_3_3_to_4_4_Ga_zircons_Ion_microprobe_evidence_for_high_%CE%B418O_continental_crust_and_oceans_in_the_Early_Archean","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/24604346/Oxygen_isotope_ratios_and_rare_earth_elements_in_3_3_to_4_4_Ga_zircons_Ion_microprobe_evidence_for_high_%CE%B418O_continental_crust_and_oceans_in_the_Early_Archean"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="6" data-entity-id="12356276" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/12356276/Correlated_microanalysis_of_zircon_Trace_element_sup_18_sup_O_and_U_Th_Pb_isotopic_constraints_on_the_igneous_origin_of_complex_3900Ma_detrital_grains">Correlated microanalysis of zircon: Trace element, ��< sup> 18</sup> O, and U��Th��Pb isotopic constraints on the igneous origin of complex> 3900Ma detrital grains</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="31054590" href="https://wisc.academia.edu/JohnValley">John Valley</a></div><p class="ds-related-work--metadata ds2-5-body-xs">2006</p><p class="ds-related-work--abstract ds2-5-body-sm">The origins of >3900 Ma detrital zircons from Western Australia are controversial, in part due to their complexity and long geologic histories. Conflicting interpretations for the genesis of these zircons propose magmatic, hydrothermal, or metamorphic origins. To test the hypothesis that these zircons preserve magmatic compositions, trace elements [rare earth elements (REE), Y, P, Th, U] were analyzed by ion microprobe from a suite of >3900 Ma zircons from Jack Hills, Western Australia, and include some of the oldest detrital zircons known (4400-4300 Ma). The same $20 lm domains previously characterized for U/Pb age, oxygen isotope composition (d 18 O), and cathodoluminescence (CL) zoning were specifically targeted for analysis. The zircons are classified into two types based on the light-REE (LREE) composition of the domain analyzed. Zircons with Type 1 domains form the largest group (37 of 42), consisting of grains that preserve evolved REE compositions typical of igneous zircon from crustal rocks. Grains with Type 1 domains display a wide range of CL zoning patterns, yield nearly concordant U/Pb ages from 4400 to 3900 Ma, and preserve a narrow range of d 18 O values from 4.7& to 7.3& that overlap or are slightly elevated relative to mantle oxygen isotope composition. Type 1 domains are interpreted to preserve magmatic compositions. Type 2 domains occur in six zircons that contain spots with enriched light-REE (LREE) compositions, here defined as having chondrite normalized values of La N > 1 and Pr N > 10. A subset of analyses in Type 2 domains appear to result from incorporation of sub-surface mineral inclusions in the analysis volume, as evidenced by positively correlated secondary ion beam intensities for LREE, P, and Y, which are anti-correlated to Si, although not all Type 2 analyses show these features. The LREE enrichment also occurs in areas with discordant U/Pb ages and/or high Th/U ratios, and is apparently associated with past or present radiation damage. The enrichment is not attributed to hydrothermal alteration, however, as oxygen isotope ratios in Type 2 domains overlap with magmatic values of Type 1 domains, and do not appear re-set as might be expected from dissolution or ion-exchange processes operating at variable temperatures. Thus, REE compositions in Type 2 domains where mineral inclusions are not suspected are best interpreted to result from localized enrichment of LREE in areas with past or present radiation damage, and with a very low fluid/rock ratio. Correlated in situ analyses allow magmatic compositions in these complex zircons to be distinguished from the effects of secondary processes. These results are additional evidence for preservation of magmatic compositions in Jack Hills zircons, and demonstrate the benefits of detailed imaging in studies of complicated detrital zircons of unknown origin. The data reported here support previous interpretations that the majority of >3900 Ma zircons from the Jack Hills have an origin in evolved granitic melts, and are evidence for the existence of continental crust very early in Earth's history.</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Correlated microanalysis of zircon: Trace element, ��\u003c sup\u003e 18\u003c/sup\u003e O, and U��Th��Pb isotopic constraints on the igneous origin of complex\u003e 3900Ma detrital grains","attachmentId":46225706,"attachmentType":"pdf","work_url":"https://www.academia.edu/12356276/Correlated_microanalysis_of_zircon_Trace_element_sup_18_sup_O_and_U_Th_Pb_isotopic_constraints_on_the_igneous_origin_of_complex_3900Ma_detrital_grains","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/12356276/Correlated_microanalysis_of_zircon_Trace_element_sup_18_sup_O_and_U_Th_Pb_isotopic_constraints_on_the_igneous_origin_of_complex_3900Ma_detrital_grains"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="7" data-entity-id="25015859" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/25015859/Correlated_microanalysis_of_zircon_Trace_element_%CE%B418O_and_U_Th_Pb_isotopic_constraints_on_the_igneous_origin_of_complex_3900Ma_detrital_grains">Correlated microanalysis of zircon: Trace element, δ18O, and U–Th–Pb isotopic constraints on the igneous origin of complex >3900Ma detrital grains</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="32816813" href="https://curtin.academia.edu/SimonWilde">Simon A Wilde</a></div><p class="ds-related-work--metadata ds2-5-body-xs">Geochimica et Cosmochimica Acta, 2006</p><p class="ds-related-work--abstract ds2-5-body-sm">The origins of >3900 Ma detrital zircons from Western Australia are controversial, in part due to their complexity and long geologic histories. Conflicting interpretations for the genesis of these zircons propose magmatic, hydrothermal, or metamorphic origins. To test the hypothesis that these zircons preserve magmatic compositions, trace elements [rare earth elements (REE), Y, P, Th, U] were analyzed by ion microprobe from a suite of >3900 Ma zircons from Jack Hills, Western Australia, and include some of the oldest detrital zircons known (4400-4300 Ma). The same $20 lm domains previously characterized for U/Pb age, oxygen isotope composition (d 18 O), and cathodoluminescence (CL) zoning were specifically targeted for analysis. The zircons are classified into two types based on the light-REE (LREE) composition of the domain analyzed. Zircons with Type 1 domains form the largest group (37 of 42), consisting of grains that preserve evolved REE compositions typical of igneous zircon from crustal rocks. Grains with Type 1 domains display a wide range of CL zoning patterns, yield nearly concordant U/Pb ages from 4400 to 3900 Ma, and preserve a narrow range of d 18 O values from 4.7& to 7.3& that overlap or are slightly elevated relative to mantle oxygen isotope composition. Type 1 domains are interpreted to preserve magmatic compositions. Type 2 domains occur in six zircons that contain spots with enriched light-REE (LREE) compositions, here defined as having chondrite normalized values of La N > 1 and Pr N > 10. A subset of analyses in Type 2 domains appear to result from incorporation of sub-surface mineral inclusions in the analysis volume, as evidenced by positively correlated secondary ion beam intensities for LREE, P, and Y, which are anti-correlated to Si, although not all Type 2 analyses show these features. The LREE enrichment also occurs in areas with discordant U/Pb ages and/or high Th/U ratios, and is apparently associated with past or present radiation damage. The enrichment is not attributed to hydrothermal alteration, however, as oxygen isotope ratios in Type 2 domains overlap with magmatic values of Type 1 domains, and do not appear re-set as might be expected from dissolution or ion-exchange processes operating at variable temperatures. Thus, REE compositions in Type 2 domains where mineral inclusions are not suspected are best interpreted to result from localized enrichment of LREE in areas with past or present radiation damage, and with a very low fluid/rock ratio. Correlated in situ analyses allow magmatic compositions in these complex zircons to be distinguished from the effects of secondary processes. These results are additional evidence for preservation of magmatic compositions in Jack Hills zircons, and demonstrate the benefits of detailed imaging in studies of complicated detrital zircons of unknown origin. The data reported here support previous interpretations that the majority of >3900 Ma zircons from the Jack Hills have an origin in evolved granitic melts, and are evidence for the existence of continental crust very early in Earth's history.</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Correlated microanalysis of zircon: Trace element, δ18O, and U–Th–Pb isotopic constraints on the igneous origin of complex \u003e3900Ma detrital grains","attachmentId":45340873,"attachmentType":"pdf","work_url":"https://www.academia.edu/25015859/Correlated_microanalysis_of_zircon_Trace_element_%CE%B418O_and_U_Th_Pb_isotopic_constraints_on_the_igneous_origin_of_complex_3900Ma_detrital_grains","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/25015859/Correlated_microanalysis_of_zircon_Trace_element_%CE%B418O_and_U_Th_Pb_isotopic_constraints_on_the_igneous_origin_of_complex_3900Ma_detrital_grains"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="8" data-entity-id="27513177" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/27513177/Potentially_biogenic_carbon_preserved_in_a_4_1_billion_year_old_zircon">Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="255103" href="https://ucla.academia.edu/ElizabethBell">Elizabeth Bell</a></div><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon","attachmentId":47767768,"attachmentType":"pdf","work_url":"https://www.academia.edu/27513177/Potentially_biogenic_carbon_preserved_in_a_4_1_billion_year_old_zircon","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/27513177/Potentially_biogenic_carbon_preserved_in_a_4_1_billion_year_old_zircon"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div><div class="ds-related-work--container js-wsj-grid-card" data-collection-position="9" data-entity-id="25015853" data-sort-order="default"><a class="ds-related-work--title js-wsj-grid-card-title ds2-5-body-md ds2-5-body-link" href="https://www.academia.edu/25015853/Magmatic_%CE%B418O_in_4400_3900_Ma_detrital_zircons_A_record_of_the_alteration_and_recycling_of_crust_in_the_Early_Archean">Magmatic δ18O in 4400–3900 Ma detrital zircons: A record of the alteration and recycling of crust in the Early Archean</a><div class="ds-related-work--metadata"><a class="js-wsj-grid-card-author ds2-5-body-sm ds2-5-body-link" data-author-id="32816813" href="https://curtin.academia.edu/SimonWilde">Simon A Wilde</a></div><p class="ds-related-work--metadata ds2-5-body-xs">Earth and Planetary Science Letters, 2005</p><p class="ds-related-work--abstract ds2-5-body-sm">Ion microprobe analyses of y 18 O in 4400-3900 Ma igneous zircons from the Jack Hills, Western Australia, provide a record of the oxygen isotope composition of magmas in the earliest Archean. We have employed a detailed analysis protocol aimed at correlating spatially related micro-volumes of zircon concordant in U/Pb age with y 18 O and internal zoning. Simultaneous analysis of 18 O and 16 O with dual Faraday cup detectors, combined with frequent standardization, has yielded data with improved accuracy and precision over prior studies, and resulted in a narrower range of what is interpreted as magmatic y 18 O in N 3900 Ma zircons. Preserved magmatic y 18 O values from individual zircons (Zrc) range from 5.3x to 7.3x (VSMOW), and increasingly deviate from the mantle range of 5.3 F 0.3x as zircons decrease in age from 4400 to 4200 Ma. Elevated y 18 O (Zrc) values up to 6.5x occur as early as 4325 Ma, which suggests that evolved rocks were incorporated into magmas within~230 Ma of Earth's accretion. Values of magmatic y 18 O (Zrc) as high as 7.3x are recorded in zircons by 4200 Ma, and are common thereafter. The protoliths of the magmas these zircons crystallized in were altered by low temperature interaction with liquid water near EarthTs surface. These results provide the strongest evidence yet for the existence of liquid water oceans and supracrustal rocks by approximately 4200 Ma, and possibly as early as 4325 Ma. The range of magmatic y 18 O values in the 4400-3900 Ma zircons is indistinguishable from Archean igneous zircons, suggesting similar magmatic processes occurred over the first two billion years of recorded Earth history. Zircons with sub-solidus alteration histories, identified by the presence of disturbed internal zoning patterns, record y 18 O values both below (4.6x) and above (10.3x) the observed range for primary magmatic zircon, and are unreliable indicators of Early Archean magma chemistry. D</p><div class="ds-related-work--ctas"><button class="ds2-5-text-link ds2-5-text-link--inline js-swp-download-button" data-signup-modal="{"location":"wsj-grid-card-download-pdf-modal","work_title":"Magmatic δ18O in 4400–3900 Ma detrital zircons: A record of the alteration and recycling of crust in the Early Archean","attachmentId":45340869,"attachmentType":"pdf","work_url":"https://www.academia.edu/25015853/Magmatic_%CE%B418O_in_4400_3900_Ma_detrital_zircons_A_record_of_the_alteration_and_recycling_of_crust_in_the_Early_Archean","alternativeTracking":true}"><span class="material-symbols-outlined" style="font-size: 18px" translate="no">download</span><span class="ds2-5-text-link__content">Download free PDF</span></button><a class="ds2-5-text-link ds2-5-text-link--inline js-wsj-grid-card-view-pdf" href="https://www.academia.edu/25015853/Magmatic_%CE%B418O_in_4400_3900_Ma_detrital_zircons_A_record_of_the_alteration_and_recycling_of_crust_in_the_Early_Archean"><span class="ds2-5-text-link__content">View PDF</span><span class="material-symbols-outlined" style="font-size: 18px" translate="no">chevron_right</span></a></div></div></div></div><div class="ds-sticky-ctas--wrapper js-loswp-sticky-ctas hidden"><div class="ds-sticky-ctas--grid-container"><div class="ds-sticky-ctas--container"><button class="ds2-5-button js-swp-download-button" data-signup-modal="{"location":"continue-reading-button--sticky-ctas","attachmentId":46225760,"attachmentType":"pdf","workUrl":null}">See full PDF</button><button class="ds2-5-button ds2-5-button--secondary js-swp-download-button" data-signup-modal="{"location":"download-pdf-button--sticky-ctas","attachmentId":46225760,"attachmentType":"pdf","workUrl":null}"><span class="material-symbols-outlined" style="font-size: 20px" translate="no">download</span>Download PDF</button></div></div></div><div class="ds-below-fold--grid-container"><div class="ds-work--container js-loswp-embedded-document"><div class="attachment_preview" data-attachment="Attachment_46225760" style="display: none"><div class="js-scribd-document-container"><div class="scribd--document-loading js-scribd-document-loader" style="display: block;"><img alt="Loading..." src="//a.academia-assets.com/images/loaders/paper-load.gif" /><p>Loading Preview</p></div></div><div style="text-align: center;"><div class="scribd--no-preview-alert js-preview-unavailable"><p>Sorry, preview is currently unavailable. 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