In Situ Identification of Hydrated Carbonates on Mars

In Situ Identification of Hydrated Carbonates on Mars | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article In Situ Identification of Hydrated Carbonates on Mars Anushree Srivastava, Andrew Steele, Linda Kah, Ryan Jakubek, Pamela Conrad, and 27 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8355174/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Hydrated carbonates uniquely record low-temperature interactions between CO₂-rich fluids and crustal rocks in water-rich conditions. Hydrated carbonates had not been previously detected in situ on the surface of Mars, but the Mars 2020 Perseverance rover reveals a local ~3.7-billion-year-old sediment preserving grains of hydrated Mg-carbonate only ~1 cm below the surface. This sediment, located at the ancient lake margin of Jezero Crater, was analyzed by the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument aboard Perseverance. The hydrated magnesium carbonate, spatially associated with amorphous silica, formed through olivine alteration by aqueous CO₂ – a process known as mineral carbonation – indicating early-stage alteration in an alkaline, water-rich environment. This carbonate is closely associated with hydrous and anhydrous sulfates, anhydrous carbonates, phosphate, and perchlorate, reflecting formation in multiple, temporally distinct aqueous environments. A very localized long-term preservation of this hydrated carbonate indicates exceptional local boundary conditions at the bedrock, including water-rich, alkaline chemistry and effective shallow-subsurface thermal and diagenetic shielding over geologic timescales. Discovery of hydrated carbonate also offers new in situ evidence of Mars’s long-missing CO2 sink. Earth and environmental sciences/Planetary science/Geochemistry Physical sciences/Astronomy and planetary science/Planetary science/Geochemistry Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SrivastavaetalHydratedCarbonatesonMarsSupplementaryDocumentDecember2025.pdf In situ Identification of Hydrated Carbonates on Mars Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8355174","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":572195711,"identity":"6af913af-dfdd-42aa-a4a2-202bb3ca32fa","order_by":0,"name":"Anushree 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Hydrated carbonates had not been previously detected in situ on the surface of Mars, but the Mars 2020 Perseverance rover reveals a local ~3.7-billion-year-old sediment preserving grains of hydrated Mg-carbonate only ~1 cm below the surface. This sediment, located at the ancient lake margin of Jezero Crater, was analyzed by the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument aboard Perseverance. The hydrated magnesium carbonate, spatially associated with amorphous silica, formed through olivine alteration by aqueous CO₂ – a process known as mineral carbonation – indicating early-stage alteration in an alkaline, water-rich environment. This carbonate is closely associated with hydrous and anhydrous sulfates, anhydrous carbonates, phosphate, and perchlorate, reflecting formation in multiple, temporally distinct aqueous environments. A very localized long-term preservation of this hydrated carbonate indicates exceptional local boundary conditions at the bedrock, including water-rich, alkaline chemistry and effective shallow-subsurface thermal and diagenetic shielding over geologic timescales. Discovery of hydrated carbonate also offers new in situ evidence of Mars’s long-missing CO2 sink.","manuscriptTitle":"In Situ Identification of Hydrated Carbonates on Mars","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-12 02:58:06","doi":"10.21203/rs.3.rs-8355174/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-astronomy","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"natastron","sideBox":"Learn more about [Nature Astronomy](http://www.nature.com/natastron/)","snPcode":"","submissionUrl":"","title":"Nature Astronomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Research","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"f1a3c909-82f6-4b5f-a2a8-de3d50ed451e","owner":[],"postedDate":"January 12th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":60893988,"name":"Earth and environmental sciences/Planetary science/Geochemistry"},{"id":60893989,"name":"Physical sciences/Astronomy and planetary science/Planetary science/Geochemistry"}],"tags":[],"updatedAt":"2026-03-27T21:10:08+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-12 02:58:06","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8355174","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8355174","identity":"rs-8355174","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}