21 results on '"Henehan, Michael J."'
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2. Adsorption pathways of boron on clay and their implications for boron cycling on land and in the ocean
- Author
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Ring, Simon J., Henehan, Michael J., Blukis, Roberts, and von Blanckenburg, Friedhelm
- Published
- 2024
- Full Text
- View/download PDF
3. Controls on potassium incorporation in foraminifera and other marine calcifying organisms
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Nambiar, Romi, Hauzer, Hagar, Gray, William R., Henehan, Michael J., Cotton, Laura, Erez, Jonathan, Rosenthal, Yair, Renema, Willem, Müller, Wolfgang, and Evans, David
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- 2023
- Full Text
- View/download PDF
4. Reconstruction of Cenozoic δ11Bsw Using a Gaussian Process
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Whiteford, Ross, primary, Heaton, Timothy J., additional, Henehan, Michael J., additional, Anagnostou, Eleni, additional, Jurikova, Hana, additional, Foster, Gavin L., additional, and Rae, James W. B., additional
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- 2024
- Full Text
- View/download PDF
5. The PhanSST global database of Phanerozoic sea surface temperature proxy data
- Author
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Judd, Emily J., Tierney, Jessica E., Huber, Brian T., Wing, Scott L., Lunt, Daniel J., Ford, Heather L., Inglis, Gordon N., McClymont, Erin L., O’Brien, Charlotte L., Rattanasriampaipong, Ronnakrit, Si, Weimin, Staitis, Matthew L., Thirumalai, Kaustubh, Anagnostou, Eleni, Cramwinckel, Marlow Julius, Dawson, Robin R., Evans, David, Gray, William R., Grossman, Ethan L., Henehan, Michael J., Hupp, Brittany N., MacLeod, Kenneth G., O’Connor, Lauren K., Sánchez Montes, Maria Luisa, Song, Haijun, and Zhang, Yi Ge
- Published
- 2022
- Full Text
- View/download PDF
6. Mg isotope composition of runoff is buffered by the regolith exchangeable pool
- Author
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Cai, Di, Henehan, Michael J., Uhlig, David, and von Blanckenburg, Friedhelm
- Published
- 2022
- Full Text
- View/download PDF
7. No ion is an island: Multiple ions influence boron incorporation into CaCO3
- Author
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Henehan, Michael J., Klein Gebbinck, Christa D., Wyman, Jillian V.B., Hain, Mathis P., Rae, James W.B., Hönisch, Bärbel, Foster, Gavin L., and Kim, Sang-Tae
- Published
- 2022
- Full Text
- View/download PDF
8. Reconstruction of Cenozoic δ11Bsw Using a Gaussian Process.
- Author
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Whiteford, Ross, Heaton, Timothy J., Henehan, Michael J., Anagnostou, Eleni, Jurikova, Hana, Foster, Gavin L., and Rae, James W. B.
- Subjects
GAUSSIAN processes ,BORON isotopes ,ATMOSPHERIC carbon dioxide ,OSMIUM isotopes ,LITHIUM isotopes ,OSMIUM ,BORON ,ISOTOPE separation - Abstract
The boron isotope ratio of seawater (δ11Bsw) is a parameter which must be known to reconstruct palaeo pH and CO2 from boron isotope measurements of marine carbonates. Beyond a few million years ago, δ11Bsw is likely to have been different to modern. Palaeo δ11Bsw can be estimated by simultaneously constraining the vertical gradients in foraminiferal δ11B (Δδ11B) and pH (ΔpH). A number of subtly different techniques have been used to estimate ΔpH in the past, all broadly based on assumptions about vertical gradients in oxygen, and/or carbon, or other carbonate system constraints. In this work we pull together existing data from previous studies, alongside a constraint on the rate of change of δ11Bsw from modeling. We combine this information in an overarching statistical framework called a Gaussian Process. The Gaussian Process technique allows us to bring together data and constraints on the rate of change in δ11Bsw to generate random plausible evolutions of δ11Bsw. We reconstruct δ11Bsw, and by extension palaeo pH, across the last 65Myr using this novel methodology. Reconstructed δ11Bsw is compared to other seawater isotope ratios, namely Sr87/86 ${}^{87/86}\mathrm{S}\mathrm{r}$, Os187/188 ${}^{187/188}\mathrm{O}\mathrm{s}$, and δ7Li, which we also reconstruct with Gaussian Processes. Our method provides a template for incorporation of future δ11Bsw constraints, and a mechanism for propagation of uncertainty in δ11Bsw into future studies. Plain Language Summary: Boron naturally exists in two forms—11B and 10B. Measuring the ratio of these two forms of boron within marine shells allows us to estimate how alkaline the ocean was in the past, which is related to how much carbon dioxide is in the atmosphere. Before we can do this calculation though, we need to know some other parameters, one of which is the relative abundance of the two forms of boron in the ocean at the time (which we call δ11Bsw). Preexisting studies have estimated δ11Bsw at particular times, and here we combine them to generate a full reconstruction across the last 65 million years, accounting for uncertainties. Our reconstruction is informed by limiting the rate at which δ11Bsw can change, based on model simulations. We provide a set of plausible evolutions of δ11Bsw which can be used in future work when calculating past ocean pH. Key Points: We reconstruct the temporal evolution of seawater isotope ratios of boron, strontium, lithium, and osmium over the last 65 million yearsThe evolution of seawater boron isotope ratio shows similarity to the evolution of strontium, lithium and osmium isotope ratiosRandomly drawn, smooth time series are provided for use in uncertainty propagation in calculation of palaeo pH [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Boron geochemistry reveals the evolution of Dead Sea brines
- Author
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Jurikova, Hana, primary, Ring, Simon J., additional, Henehan, Michael J., additional, Neugebauer, Ina, additional, Schröder, Birgit, additional, Müller, Daniela, additional, Schwab, Markus J., additional, Tjallingii, Rik, additional, Brauer, Achim, additional, and Blanchet, Cécile, additional
- Published
- 2023
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10. Silicate weathering feedback hindered by clay formation
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Henehan, Michael J., primary
- Published
- 2023
- Full Text
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11. Continental flood basalts do not drive later Phanerozoic extinctions
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Henehan, Michael J., primary and Witts, James D., additional
- Published
- 2023
- Full Text
- View/download PDF
12. Toward a Cenozoic history of atmospheric CO 2
- Author
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Hönisch, Bärbel, Royer, Dana L., Breecker, Daniel O., Polissar, Pratigya J., Bowen, Gabriel J., Henehan, Michael J., Cui, Ying, Steinthorsdottir, Margret, McElwain, Jennifer C., Kohn, Matthew J., Pearson, Ann, Phelps, Samuel R., Uno, Kevin T., Ridgwell, Andy, Anagnostou, Eleni, Austermann, Jacqueline, Badger, Marcus P. S., Barclay, Richard S., Bijl, Peter K., Chalk, Thomas B., Scotese, Christopher R., de la Vega, Elwyn, DeConto, Robert M., Dyez, Kelsey A., Ferrini, Vicki, Franks, Peter J., Giulivi, Claudia F., Gutjahr, Marcus, Harper, Dustin T., Haynes, Laura L., Huber, Matthew, Snell, Kathryn E., Keisling, Benjamin A., Konrad, Wilfried, Lowenstein, Tim K., Malinverno, Alberto, Guillermic, Maxence, Mejía, Luz María, Milligan, Joseph N., Morton, John J., Nordt, Lee, Whiteford, Ross, Roth-Nebelsick, Anita, Rugenstein, Jeremy K. C., Schaller, Morgan F., Sheldon, Nathan D., Sosdian, Sindia, Wilkes, Elise B., Witkowski, Caitlyn R., Zhang, Yi Ge, Anderson, Lloyd, Beerling, David J., Bolton, Clara, Cerling, Thure E., Cotton, Jennifer M., Da, Jiawei, Ekart, Douglas D., Foster, Gavin L., Greenwood, David R., Hyland, Ethan G., Jagniecki, Elliot A., Jasper, John P., Kowalczyk, Jennifer B., Kunzmann, Lutz, Kürschner, Wolfram M., Lawrence, Charles E., Lear, Caroline H., Martínez-Botí, Miguel A., Maxbauer, Daniel P., Montagna, Paolo, Naafs, B. David A., Rae, James W. B., Raitzsch, Markus, Retallack, Gregory J., Ring, Simon J., Seki, Osamu, Sepúlveda, Julio, Sinha, Ashish, Tesfamichael, Tekie F., Tripati, Aradhna, van der Burgh, Johan, Yu, Jimin, Zachos, James C., Zhang, Laiming, Hönisch, Bärbel, Royer, Dana L., Breecker, Daniel O., Polissar, Pratigya J., Bowen, Gabriel J., Henehan, Michael J., Cui, Ying, Steinthorsdottir, Margret, McElwain, Jennifer C., Kohn, Matthew J., Pearson, Ann, Phelps, Samuel R., Uno, Kevin T., Ridgwell, Andy, Anagnostou, Eleni, Austermann, Jacqueline, Badger, Marcus P. S., Barclay, Richard S., Bijl, Peter K., Chalk, Thomas B., Scotese, Christopher R., de la Vega, Elwyn, DeConto, Robert M., Dyez, Kelsey A., Ferrini, Vicki, Franks, Peter J., Giulivi, Claudia F., Gutjahr, Marcus, Harper, Dustin T., Haynes, Laura L., Huber, Matthew, Snell, Kathryn E., Keisling, Benjamin A., Konrad, Wilfried, Lowenstein, Tim K., Malinverno, Alberto, Guillermic, Maxence, Mejía, Luz María, Milligan, Joseph N., Morton, John J., Nordt, Lee, Whiteford, Ross, Roth-Nebelsick, Anita, Rugenstein, Jeremy K. C., Schaller, Morgan F., Sheldon, Nathan D., Sosdian, Sindia, Wilkes, Elise B., Witkowski, Caitlyn R., Zhang, Yi Ge, Anderson, Lloyd, Beerling, David J., Bolton, Clara, Cerling, Thure E., Cotton, Jennifer M., Da, Jiawei, Ekart, Douglas D., Foster, Gavin L., Greenwood, David R., Hyland, Ethan G., Jagniecki, Elliot A., Jasper, John P., Kowalczyk, Jennifer B., Kunzmann, Lutz, Kürschner, Wolfram M., Lawrence, Charles E., Lear, Caroline H., Martínez-Botí, Miguel A., Maxbauer, Daniel P., Montagna, Paolo, Naafs, B. David A., Rae, James W. B., Raitzsch, Markus, Retallack, Gregory J., Ring, Simon J., Seki, Osamu, Sepúlveda, Julio, Sinha, Ashish, Tesfamichael, Tekie F., Tripati, Aradhna, van der Burgh, Johan, Yu, Jimin, Zachos, James C., and Zhang, Laiming
- Abstract
The geological record encodes the relationship between climate and atmospheric carbon dioxide (CO 2 ) over long and short timescales, as well as potential drivers of evolutionary transitions. However, reconstructing CO 2 beyond direct measurements requires the use of paleoproxies and herein lies the challenge, as proxies differ in their assumptions, degree of understanding, and even reconstructed values. In this study, we critically evaluated, categorized, and integrated available proxies to create a high-fidelity and transparently constructed atmospheric CO 2 record spanning the past 66 million years. This newly constructed record provides clearer evidence for higher Earth system sensitivity in the past and for the role of CO 2 thresholds in biological and cryosphere evolution. Editor’s summary The concentration of atmospheric carbon dioxide is a fundamental driver of climate, but its value is difficult to determine for times older than the roughly 800,000 years for which ice core records are available. The Cenozoic Carbon dioxide Proxy Integration Project (CenCO2PIP) Consortium assessed a comprehensive collection of proxy determinations to define the atmospheric carbon dioxide record for the past 66 million years. This synthesis provides the most complete record yet available and will help to better establish the role of carbon dioxide in climate, biological, and cryosphere evolution. — H. Jesse Smith
- Published
- 2023
- Full Text
- View/download PDF
13. The PhanSST global database of Phanerozoic sea surface temperature proxy data
- Author
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Stratigraphy and paleontology, Stratigraphy & paleontology, Judd, Emily J., Tierney, Jessica E., Huber, Brian T., Wing, Scott L., Lunt, Daniel J., Ford, Heather L., Inglis, Gordon N., McClymont, Erin L., O’Brien, Charlotte L., Rattanasriampaipong, Ronnakrit, Si, Weimin, Staitis, Matthew L., Thirumalai, Kaustubh, Anagnostou, Eleni, Cramwinckel, Margot J., Dawson, Robin R., Evans, David, Gray, William R., Grossman, Ethan L., Henehan, Michael J., Hupp, Brittany N., MacLeod, Kenneth G., O’Connor, Lauren K., Sánchez Montes, Maria Luisa, Song, Haijun, Zhang, Yi Ge, Stratigraphy and paleontology, Stratigraphy & paleontology, Judd, Emily J., Tierney, Jessica E., Huber, Brian T., Wing, Scott L., Lunt, Daniel J., Ford, Heather L., Inglis, Gordon N., McClymont, Erin L., O’Brien, Charlotte L., Rattanasriampaipong, Ronnakrit, Si, Weimin, Staitis, Matthew L., Thirumalai, Kaustubh, Anagnostou, Eleni, Cramwinckel, Margot J., Dawson, Robin R., Evans, David, Gray, William R., Grossman, Ethan L., Henehan, Michael J., Hupp, Brittany N., MacLeod, Kenneth G., O’Connor, Lauren K., Sánchez Montes, Maria Luisa, Song, Haijun, and Zhang, Yi Ge
- Published
- 2022
14. Fluid-rock interactions and amphibolitisation of the lower continental crust (The Kråkenes Gabbro, Western Gneiss Region, Norway)
- Author
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Bläsing, Saskia, primary, John, Timm, additional, Vrijmoed, Johannes C., additional, Henehan, Michael J., additional, and Frick, Daniel A., additional
- Published
- 2022
- Full Text
- View/download PDF
15. Secondary Minerals Drive Extreme Lithium Isotope Fractionation During Tropical Weathering
- Author
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Chapela Lara, María, primary, Buss, Heather L., additional, Henehan, Michael J., additional, Schuessler, Jan A., additional, and McDowell, William H., additional
- Published
- 2022
- Full Text
- View/download PDF
16. Electromyographic Characteristics of a Single Motion Shoulder Exercise: A Pilot Study Investigating a Novel Shoulder Exercise
- Author
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Henehan, Michael J, primary, Brand-Perez, Tamar, additional, Peng, Jeffrey C, additional, and Tsuruike, Masaaki, additional
- Published
- 2022
- Full Text
- View/download PDF
17. Carbon Cycling at the Dawn of the Cenozoic
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Henehan, Michael J., Barnet, James, Kalderon-Asael, Boriana, Özen, Volkan, Hull, Pincelli, Planavsky, Noah, Ridgwell, Andy, Rae, James, Witts, James, Littler, Kate, Greene, Sarah, Thomas, Ellen, Hain, Mathis, and von Blanckenburg, Friedhelm
- Abstract
The Paleocene – the first epoch of the Cenozoic (66–56 Ma) – spans numerous notable climatic and biogeochemical phenomena. In the oceans, the Paleocene saw the drawn-out recovery of calcifying plankton communities after severe extinction at the K-Pg, followed by one of the largest excursions in benthic foraminiferal δ13C values of the last 100 Myr1. On land, an as-yet-unexplained extreme step-change in global weathering regime is indicated by marine carbonate δ7Li values2. More generally, although benthic foraminiferal δ18O suggests a greenhouse climate much warmer than today3, proxy estimates of atmospheric CO2 in the Paleocene mostly indicate CO2 levels similar to those of the relatively colder late Neogene4. Here, I will show some new benthic and planktic foraminiferal boron and lithium isotope data that address outstanding puzzles in geochemical cycling and ocean chemistry at the dawn of the Cenozoic. 1. Friedrich, O., Norris, R. D. & Erbacher, J. Evolution of middle to Late Cretaceous oceans--A 55 m.y. record of Earth’s temperature and carbon cycle. Geology 40, 107–110 (2012). 2. Misra, S. & Froelich, P. N. Lithium Isotope History of Cenozoic Seawater: Changes in Silicate Weathering and Reverse Weathering. Science 335, 818–823 (2012). 3. Westerhold, T. et al. An astronomically dated record of Earth’s climate and its predictability over the last 66 million years. Science 369, 1383–1387 (2020). 4. Beerling, D. J. & Royer, D. L. Convergent Cenozoic CO2 history. Nat. Geosci. 4, 418–420 (2011).
- Published
- 2022
- Full Text
- View/download PDF
18. Clay dissolution/re-precipitation drives extreme Li isotope fractionation during tropical weathering
- Author
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Chapela Lara, Maria, Buss, Heather L., Henehan, Michael J., Schuessler, Jan A., and McDowell, William H.
- Abstract
Lithium isotopes are the best tracers of weathering intensity, but little is known about the processes that fractionate them in highly weathered settings, where secondary minerals play a dominant role in weathering reactions. To help fill this gap in our knowledge of Li isotope systematics, we investigated Li isotope fractionation at an andesitic catchment in Puerto Rico*, where the highest rates of silicate weathering on Earth have been documented. We found the lowest δ7Li values published to date for porewater (−27‰) and bulk regolith (−38‰), representing apparent fractionations relative to parent rock of −31‰ and −42‰, respectively. We also found δ7Li values that are lower in the exchangeable fraction (−49‰) than in the bulk regolith or porewater, the opposite than expected from secondary mineral precipitation. We interpret these large isotopic offsets and the unusual relationships between Li pools as resulting from two distinct weathering processes at different depths in the regolith. At the bedrock-regolith transition (9.3–8.5 m depth), secondary mineral precipitation preferentially retains the lighter 6Li isotope. These minerals then dissolve further up the profile, leaching 6Li from the bulk solid, with a total variation of about +50‰ within the profile, attributable primarily to clay dissolution. Importantly, stream water δ7Li (about +35‰) is divorced entirely from these regolith weathering processes, instead reflecting deeper weathering reactions (>9.3 m). Our work thus shows that the δ7Li of waters draining highly weathered catchments may reflect bedrock mineralogy and hydrology, rather than weathering intensity in the regolith covering the catchment. *Chapela_Lara_et_al., 2022, JGR-ES.
- Published
- 2022
- Full Text
- View/download PDF
19. Reconstruction of Cenozoic δ11BswUsing a Gaussian Process
- Author
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Whiteford, Ross, Heaton, Timothy J., Henehan, Michael J., Anagnostou, Eleni, Jurikova, Hana, Foster, Gavin L., and Rae, James W. B.
- Abstract
The boron isotope ratio of seawater (δ11Bsw) is a parameter which must be known to reconstruct palaeo pH and CO2from boron isotope measurements of marine carbonates. Beyond a few million years ago, δ11Bswis likely to have been different to modern. Palaeo δ11Bswcan be estimated by simultaneously constraining the vertical gradients in foraminiferal δ11B (Δδ11B) and pH (ΔpH). A number of subtly different techniques have been used to estimate ΔpH in the past, all broadly based on assumptions about vertical gradients in oxygen, and/or carbon, or other carbonate system constraints. In this work we pull together existing data from previous studies, alongside a constraint on the rate of change of δ11Bswfrom modeling. We combine this information in an overarching statistical framework called a Gaussian Process. The Gaussian Process technique allows us to bring together data and constraints on the rate of change in δ11Bswto generate random plausible evolutions of δ11Bsw. We reconstruct δ11Bsw, and by extension palaeo pH, across the last 65Myr using this novel methodology. Reconstructed δ11Bswis compared to other seawater isotope ratios, namely Sr87/86${}^{87/86}\mathrm{S}\mathrm{r}$, Os187/188${}^{187/188}\mathrm{O}\mathrm{s}$, and δ7Li, which we also reconstruct with Gaussian Processes. Our method provides a template for incorporation of future δ11Bswconstraints, and a mechanism for propagation of uncertainty in δ11Bswinto future studies. Boron naturally exists in two forms—11B and 10B. Measuring the ratio of these two forms of boron within marine shells allows us to estimate how alkaline the ocean was in the past, which is related to how much carbon dioxide is in the atmosphere. Before we can do this calculation though, we need to know some other parameters, one of which is the relative abundance of the two forms of boron in the ocean at the time (which we call δ11Bsw). Preexisting studies have estimated δ11Bswat particular times, and here we combine them to generate a full reconstruction across the last 65 million years, accounting for uncertainties. Our reconstruction is informed by limiting the rate at which δ11Bswcan change, based on model simulations. We provide a set of plausible evolutions of δ11Bswwhich can be used in future work when calculating past ocean pH. We reconstruct the temporal evolution of seawater isotope ratios of boron, strontium, lithium, and osmium over the last 65 million yearsThe evolution of seawater boron isotope ratio shows similarity to the evolution of strontium, lithium and osmium isotope ratiosRandomly drawn, smooth time series are provided for use in uncertainty propagation in calculation of palaeo pH We reconstruct the temporal evolution of seawater isotope ratios of boron, strontium, lithium, and osmium over the last 65 million years The evolution of seawater boron isotope ratio shows similarity to the evolution of strontium, lithium and osmium isotope ratios Randomly drawn, smooth time series are provided for use in uncertainty propagation in calculation of palaeo pH
- Published
- 2024
- Full Text
- View/download PDF
20. Secondary Minerals Drive Extreme Lithium Isotope Fractionation During Tropical Weathering
- Author
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María Chapela Lara, Heather L. Buss, Michael J. Henehan, Jan A. Schuessler, William H. McDowell, Buss, Heather L., 3 School of Earth Sciences University of Bristol Bristol UK, Henehan, Michael J., 2 GFZ German Research Centre for Geosciences Section 3.3 Earth Surface Geochemistry Potsdam Germany, Schuessler, Jan A., McDowell, William H., and 1 Department of Natural Resources and the Environment University of New Hampshire Durham NH USA
- Subjects
Geophysics ,ddc:551.9 ,Earth-Surface Processes - Abstract
Lithium isotopes are used to trace weathering intensity, but little is known about the processes that fractionate them in highly weathered settings, where secondary minerals play a dominant role in weathering reactions. To help fill this gap in our knowledge of Li isotope systematics, we investigated Li isotope fractionation at an andesitic catchment in Puerto Rico, where the highest rates of silicate weathering on Earth have been documented. We found the lowest δ7Li values published to date for porewater (−27‰) and bulk regolith (−38‰), representing apparent fractionations relative to parent rock of −31‰ and −42‰, respectively. We also found δ7Li values that are lower in the exchangeable fraction than in the bulk regolith or porewater, the opposite than expected from secondary mineral precipitation. We interpret these large isotopic offsets and the unusual relationships between Li pools as resulting from two distinct weathering processes at different depths in the regolith. At the bedrock‐regolith transition (9.3–8.5 m depth), secondary mineral precipitation preferentially retains the lighter 6Li isotope. These minerals then dissolve further up the profile, leaching 6Li from the bulk solid, with a total variation of about +50‰ within the profile, attributable primarily to clay dissolution. Importantly, streamwater δ7Li (about +35‰) is divorced entirely from these regolith weathering processes, instead reflecting deeper weathering reactions (>9.3 m). Our work thus shows that the δ7Li of waters draining highly weathered catchments may reflect bedrock mineralogy and hydrology, rather than weathering intensity in the regolith covering the catchment., Plain Language Summary: Weathering is the process by which rocks are altered at the Earth's surface, transforming fresh minerals into clays with some loss of chemical elements to rivers and eventually oceans. Understanding how intense weathering is now, and has been in the past, is important because it supplies nutrients for ecosystems and is part of the Earth's long‐term carbon cycle (and thus, climate regulation). To do this, geochemists have developed tracers of weathering intensity, of which Li isotopes (expressed as δ7Li) are considered to be the best. However, we know little about the behavior of Li isotopes in the tropics, where weathering is the most intense. To help make δ7Li a more robust tracer, we sampled a 10 m deep soil profile at a tropical catchment in Puerto Rico where rocks are dissolving very fast. We found that weathering here is so intense that clays are continuously dissolving, producing the lowest δ7Li values ever recorded on Earth, but that the stream water draining the catchment does not reflect these values. Our work thus expands the range of known values of this tracer and warns geochemists that δ7Li in rivers might not be directly related to weathering intensity in tropical catchments., Key Points: Lowest δ7Li values reported to date in nature (porewater = −27‰; bulk regolith = −38‰; exchangeable Lithium (Li) = −50‰). Large isotopic differences driven by clay precipitation, dissolution, and re‐precipitation processes. Li isotopes may not be appropriate tracers of weathering intensity for very highly weathered catchments., National Science Foundation (NSF) http://dx.doi.org/10.13039/100000001, Alexander von Humboldt‐Stiftung (Humboldt‐Stiftung) http://dx.doi.org/10.13039/100005156, https://doi.org/10.4211/hs.28acde53dc5549f4a6e5d820364dd216
- Published
- 2022
21. Toward a Cenozoic history of atmospheric CO 2 .
- Author
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Hönisch B, Royer DL, Breecker DO, Polissar PJ, Bowen GJ, Henehan MJ, Cui Y, Steinthorsdottir M, McElwain JC, Kohn MJ, Pearson A, Phelps SR, Uno KT, Ridgwell A, Anagnostou E, Austermann J, Badger MPS, Barclay RS, Bijl PK, Chalk TB, Scotese CR, de la Vega E, DeConto RM, Dyez KA, Ferrini V, Franks PJ, Giulivi CF, Gutjahr M, Harper DT, Haynes LL, Huber M, Snell KE, Keisling BA, Konrad W, Lowenstein TK, Malinverno A, Guillermic M, Mejía LM, Milligan JN, Morton JJ, Nordt L, Whiteford R, Roth-Nebelsick A, Rugenstein JKC, Schaller MF, Sheldon ND, Sosdian S, Wilkes EB, Witkowski CR, Zhang YG, Anderson L, Beerling DJ, Bolton C, Cerling TE, Cotton JM, Da J, Ekart DD, Foster GL, Greenwood DR, Hyland EG, Jagniecki EA, Jasper JP, Kowalczyk JB, Kunzmann L, Kürschner WM, Lawrence CE, Lear CH, Martínez-Botí MA, Maxbauer DP, Montagna P, Naafs BDA, Rae JWB, Raitzsch M, Retallack GJ, Ring SJ, Seki O, Sepúlveda J, Sinha A, Tesfamichael TF, Tripati A, van der Burgh J, Yu J, Zachos JC, and Zhang L
- Abstract
The geological record encodes the relationship between climate and atmospheric carbon dioxide (CO
2 ) over long and short timescales, as well as potential drivers of evolutionary transitions. However, reconstructing CO2 beyond direct measurements requires the use of paleoproxies and herein lies the challenge, as proxies differ in their assumptions, degree of understanding, and even reconstructed values. In this study, we critically evaluated, categorized, and integrated available proxies to create a high-fidelity and transparently constructed atmospheric CO2 record spanning the past 66 million years. This newly constructed record provides clearer evidence for higher Earth system sensitivity in the past and for the role of CO2 thresholds in biological and cryosphere evolution.- Published
- 2023
- Full Text
- View/download PDF
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