The origin of carbonate mud and implications for global climate

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dc.contributor.authorGeyman, Emily
dc.contributor.authorWu, Ziman
dc.contributor.authorNadeau, Matthew
dc.contributor.authorEdmonsond, Stacey
dc.contributor.authorTurner, Turner
dc.contributor.authorPurkis, Sam
dc.contributor.authorHowes, Bolton
dc.contributor.authorDyer, Blake
dc.contributor.authorAhm, Anne-Sofie
dc.contributor.authorYao, Nan
dc.contributor.authorDeutsch, Curtis
dc.contributor.authorHiggins, John
dc.contributor.authorStolper, Daniel
dc.contributor.authorMaloof, Adam
dc.date.accessioned2026-07-07T17:33:21Z
dc.date.available2026-07-07T17:33:21Z
dc.date.issued2022
dc.description.abstractCarbonate mud represents one of the most important geochemical archives for reconstructing ancient climatic, environmental, and evolutionary change from the rock record. Mud also represents a major sink in the global carbon cycle. Yet, there remains no consensus about how and where carbonate mud is formed. Here, we present stable isotope and trace-element data from carbonate constituents in the Bahamas, including ooids, corals, foraminifera, and algae. We use geochemical fingerprinting to demonstrate that carbonate mud cannot be sourced from the abrasion and mixture of any combination of these macroscopic grains. Instead, an inverse Bayesian mixing model requires the presence of an additional aragonite source. We posit that this source represents a direct seawater precipitate. We use geological and geochemical data to show that “whitings” are unlikely to be the dominant source of this precipitate and, instead, present a model for mud precipitation on the bank margins that can explain the geographical distribution, clumped-isotope thermometry, and stable isotope signature of carbonate mud. Next, we address the enigma of why mud and ooids are so abundant in the Bahamas, yet so rare in the rest of the world: Mediterranean outflow feeds the Bahamas with the most alkaline waters in the modern ocean(>99.7th-percentile). Such high alkalinity appears to be a prerequisite for the nonskeletal carbonate factory because, when Mediterranean outflow was reduced in the Miocene, Bahamian carbonate export ceased for 3-million-years. Finally, we show how shutting off and turning on the shallow carbonate factory can send ripples through the global climate system.
dc.description.reviewstatusReviewed
dc.description.scholarlevelFaculty
dc.description.sponsorshipThis material is based on work supported by NSF Division of Earth Sciences Grant 1410317, the High Meadows Environmental Institute, the Geological Society of America Stephen G. Pollock Student Research Grant, the Evolving Earth Foundation, and the Princeton Geosciences Student Research Fund. E.C.G. thanks the NSF Graduate Research Fellowships Program and the Fannie and John Hertz Foundation. D.A.S. acknowledges support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division, under Award Number DE-AC02-05CH11231. We acknowledge the use of Princeton’s Imaging and Analysis Center, which is partially supported through the Princeton Center for Complex Materials, an NSF Materials Research Science and Engineering Centers program (DMR-2011750).
dc.identifier.citationGeyman, E. C., Wu, Z., Nadeau, M. D., Edmonsond, S., Turner, A., Purkis, S. J., Howes, B., Dyer, B., Ahm, A.-S. C., Yao, N., Deutsch, C. A., Higgins, J. A., Stolper, D. A., & Maloof, A. C. (2022). The origin of carbonate mud and implications for global climate. Proceedings of the National Academy of Sciences - PNAS, 119(43), Article e2210617119. https://doi.org/10.1073/pnas.2210617119Geyman, E. C., Wu, Z., Nadeau, M. D., Edmonsond, S., Turner, A., Purkis, S. J., Howes, B., Dyer, B., Ahm, A.-S. C., Yao, N., Deutsch, C. A., Higgins, J. A., Stolper, D. A., & Maloof, A. C. (2022). The origin of carbonate mud and implications for global climate. Proceedings of the National Academy of Sciences - PNAS, 119(43), Article e2210617119. https://doi.org/10.1073/pnas.2210617119
dc.identifier.urihttps://doi.org/10.1073/pnas.2210617119
dc.identifier.urihttps://hdl.handle.net/1828/24051
dc.language.isoen
dc.publisherProceedings of the National Academy of Sciences
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectBahamas
dc.subjectcarbonates
dc.subjectgeochemistry
dc.subjectpCO2
dc.subjectclimate
dc.subject.departmentSchool of Earth and Ocean Sciences
dc.titleThe origin of carbonate mud and implications for global climate
dc.typeArticle

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