108 results on '"Hilton, Robert G."'
Search Results
2. Concentration‐Discharge Relationships of Dissolved Rhenium in Alpine Catchments Reveal Its Use as a Tracer of Oxidative Weathering
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Hilton, Robert G, Turowski, Jens M, Winnick, Matthew, Dellinger, Mathieu, Schleppi, Patrick, Williams, Kenneth H, Lawrence, Corey R, Maher, Katharine, West, Martin, and Hayton, Amanda
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Hydrology ,Earth Sciences ,Atmospheric Sciences ,Geochemistry ,Geology ,oxidative weathering ,trace metals ,rhenium ,catchment hydrology ,rock organic carbon ,Physical Geography and Environmental Geoscience ,Civil Engineering ,Environmental Engineering ,Civil engineering ,Environmental engineering - Abstract
Oxidative weathering of sedimentary rocks plays an important role in the global carbon cycle. Rhenium (Re) has been proposed as a tracer of rock organic carbon (OCpetro) oxidation. However, the sources of Re and its mobilization by hydrological processes remain poorly constrained. Here, we examine dissolved Re as a function of water discharge, using samples collected from three alpine catchments that drain sedimentary rocks in Switzerland (Erlenbach and Vogelbach) and Colorado, USA (East River). The Swiss catchments reveal a higher dissolved Re flux in the catchment with higher erosion rates, but have similar [Re]/[Na+] and [Re]/[SO42−] ratios, which indicate a dominance of Re from OCpetro. Despite differences in rock type and hydro-climatic setting, the three catchments have a positive correlation between river water [Re]/[Na+] and [Re]/[SO42−] and water discharge. We propose that this reflects preferential routing of Re from a near-surface, oxidative weathering zone. The observations support the use of Re as a proxy to trace rock-organic carbon oxidation, and suggest it may be a hydrological tracer of vadose zone processes. We apply the Re proxy and estimate CO2 release by OCpetro oxidation of 5.7 +6.6/−2.0 tC km−2 yr−1 for the Erlenbach. The overall weathering intensity was ∼40%, meaning that the corresponding export of unweathered OCpetro in river sediments is large, and the findings call for more measurements of OCpetro oxidation in mountains and rivers as they cross floodplains.
- Published
- 2021
3. Detecting vulnerability of humid tropical forests to multiple stressors
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Saatchi, Sassan, Longo, Marcos, Xu, Liang, Yang, Yan, Abe, Hitofumi, André, Michel, Aukema, Juliann E, Carvalhais, Nuno, Cadillo-Quiroz, Hinsby, Cerbu, Gillian Ann, Chernela, Janet M, Covey, Kristofer, Sánchez-Clavijo, Lina María, Cubillos, Isai V, Davies, Stuart J, De Sy, Veronique, De Vleeschouwer, Francois, Duque, Alvaro, Durieux, Alice Marie Sybille, De Avila Fernandes, Kátia, Fernandez, Luis E, Gammino, Victoria, Garrity, Dennis P, Gibbs, David A, Gibbon, Lucy, Gowae, Gae Yansom, Hansen, Matthew, Harris, Nancy Lee, Healey, Sean P, Hilton, Robert G, Johnson, Christine May, Kankeu, Richard Sufo, Laporte-Goetz, Nadine Therese, Lee, Hyongki, Lovejoy, Thomas, Lowman, Margaret, Lumbuenamo, Raymond, Malhi, Yadvinder, Martinez, Jean-Michel M Albert, Nobre, Carlos, Pellegrini, Adam, Radachowsky, Jeremy, Román, Francisco, Russell, Diane, Sheil, Douglas, Smith, Thomas B, Spencer, Robert GM, Stolle, Fred, Tata, Hesti Lestari, del Castillo Torres, Dennis, Tshimanga, Raphael Muamba, Vargas, Rodrigo, Venter, Michelle, West, Joshua, Widayati, Atiek, Wilson, Sylvia N, Brumby, Steven, and Elmore, Aurora C
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Life on Land ,Climate Action - Abstract
Humid tropical forests play a dominant role in the functioning of Earth but are under increasing threat from changes in land use and climate. How forest vulnerability varies across space and time and what level of stress forests can tolerate before facing a tipping point are poorly understood. Here, we develop a tropical forest vulnerability index (TFVI) to detect and evaluate the vulnerability of global tropical forests to threats across space and time. We show that climate change together with land-use change have slowed the recovery rate of forest carbon cycling. Temporal autocorrelation, as an indicator of this slow recovery, increases substantially for above-ground biomass, gross primary production, and evapotranspiration when climate stress reaches a critical level. Forests in the Americas exhibit extensive vulnerability to these stressors, while in Africa, forests show relative resilience to climate, and in Asia reveal more vulnerability to land use and fragmentation. TFVI can systematically track the response of tropical forests to multiple stressors and provide early-warning signals for regions undergoing critical transitions.
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- 2021
4. Millennial-aged pyrogenic carbon in high-latitude mineral soils
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Schiedung, Marcus, primary, Ascough, Philippa, additional, Bellè, Severin-Luca, additional, Bird, Michael I., additional, Bröder, Lisa, additional, Haghipour, Negar, additional, Hilton, Robert G., additional, Lattaud, Julie, additional, and Abiven, Samuel, additional
- Published
- 2024
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5. Biogeochemical consequences of a changing Arctic shelf seafloor ecosystem
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März, Christian, Freitas, Felipe S., Faust, Johan C., Godbold, Jasmin A., Henley, Sian F., Tessin, Allyson C., Abbott, Geoffrey D., Airs, Ruth, Arndt, Sandra, Barnes, David K. A., Grange, Laura J., Gray, Neil D., Head, Ian M., Hendry, Katharine R., Hilton, Robert G., Reed, Adam J., Rühl, Saskia, Solan, Martin, Souster, Terri A., Stevenson, Mark A., Tait, Karen, Ward, James, and Widdicombe, Stephen
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- 2022
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6. Hydrological control of river and seawater lithium isotopes
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Zhang, Fei, Dellinger, Mathieu, Hilton, Robert G., Yu, Jimin, Allen, Mark B., Densmore, Alexander L., Sun, Hui, and Jin, Zhangdong
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- 2022
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7. Global silicate weathering flux overestimated because of sediment–water cation exchange
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Tipper, Edward T., Stevenson, Emily I., Alcock, Victoria, Knight, Alasdair C. G., Baronas, J. Jotautas, Hilton, Robert G., Bickle, Mike J., Larkin, Christina S., Feng, Linshu, Relph, Katy E., and Hughes, Genevieve
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- 2021
8. Probing the exchange of CO2 and O2 in the shallow critical zone during weathering of marl and black shale
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Roylands, Tobias, Hilton, Robert G., Mcclymont, Erin L., Garnett, Mark H., Soulet, Guillaume, Klotz, Sébastien, Degler, Mathis, Napoleoni, Felipe, Le Bouteiller, Caroline, Roylands, Tobias, Hilton, Robert G., Mcclymont, Erin L., Garnett, Mark H., Soulet, Guillaume, Klotz, Sébastien, Degler, Mathis, Napoleoni, Felipe, and Le Bouteiller, Caroline
- Abstract
Chemical weathering of sedimentary rocks can release carbon dioxide (CO2) and consume oxygen (O2) via the oxidation of petrogenic organic carbon and sulfide minerals. These pathways govern Earth's surface system and climate over geological timescales, but the present-day weathering fluxes and their environmental controls are only partly constrained due to a lack of in situ measurements. Here, we investigate the gaseous exchange of CO2 and O2 during the oxidative weathering of black shales and marls exposed in the French southern Alps. On six field trips over 1 year, we use drilled headspace chambers to measure the CO2 concentrations in the shallow critical zone and quantify CO2 fluxes in real time. Importantly, we develop a new approach to estimate the volume of rock that contributes CO2 to a chamber, and assess effective diffusive gas exchange, by first quantifying the mass of CO2 that is stored in a chamber and connected rock pores. Both rock types are characterized by similar contributing rock volumes and diffusive movement of CO2. However, CO2 emissions differed between the rock types, with yields over rock outcrop surfaces (inferred from the contributing rock volume and the local weathering depths) ranging on average between 73 and 1108 tCkm-2yr-1 for black shales and between 43 and 873 tCkm-2yr-1 for marls over the study period. Having quantified diffusive processes, chamber-based O2 concentration measurements are used to calculate O2 fluxes. The rate of O2 consumption increased with production of CO2, and with increased temperature, with an average O2:CO2 molar ratio of 10:1. If O2 consumption occurs by both rock organic carbon oxidation and carbonate dissolution coupled to sulfide oxidation, either an additional O2 sink needs to be identified or significant export of dissolved inorganic carbon occurs from the weathering zone. Together, our findings refine the tools we have to probe CO2 and O2 exchange in rocks at Earth's surface and shed new light on CO2 and
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- 2024
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9. The Global Turbidity Current Pump and Its Implications for Organic Carbon Cycling
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Talling, Peter J., Hage, Sophie, Baker, Megan L., Bianchi, Thomas S., Hilton, Robert G., Maier, Katherine L., Talling, Peter J., Hage, Sophie, Baker, Megan L., Bianchi, Thomas S., Hilton, Robert G., and Maier, Katherine L.
- Abstract
Submarine turbidity currents form the largest sediment accumulations on Earth, raising the question of their role in global carbon cycles. It was previously inferred that terrestrial organic carbon was primarily incinerated on shelves and that most turbidity current systems are presently inactive. Turbidity currents were thus not considered in global carbon cycles, and the burial efficiency of global terrestrial organic carbon was considered low to moderate (∼10–44%). However, recent work has shown that burial of terrestrial organic carbon by turbidity currents is highly efficient (>60–100%) in a range of settings and that flows occur more frequently than once thought, although they were far more active at sea-level lowstands. This leads to revised global estimates for mass flux (∼62–90 Mt C/year) and burial efficiency (∼31–45%) of terrestrial organic carbon in marine sediments. Greatly increased burial fluxes during sea-level lowstands are also likely underestimated; thus, organic carbon cycling by turbidity currents could play a role in long-term changes in atmospheric CO2 and climate. Expected final online publication date for the Annual Review of Marine Science, Volume 16 is January 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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- 2024
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10. How is particulate organic carbon transported through the river-fed Congo Submarine Canyon to the deep-sea?
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Hage, Sophie, Baker, Megan L., Babonneau, Nathalie, Soulet, Guillaume, Dennielou, Bernard, Silva Jacinto, Ricardo, Hilton, Robert G., Galy, Valier, Baudin, François, Rabouille, Christophe, Vic, Clement, Sahin, Sefa, Açikalin, Sanem, Talling, Peter J., Hage, Sophie, Baker, Megan L., Babonneau, Nathalie, Soulet, Guillaume, Dennielou, Bernard, Silva Jacinto, Ricardo, Hilton, Robert G., Galy, Valier, Baudin, François, Rabouille, Christophe, Vic, Clement, Sahin, Sefa, Açikalin, Sanem, and Talling, Peter J.
- Abstract
The transfer of carbon from land to the near-coastal ocean is increasingly being recognized in global carbon budgets. However, a more direct transfer of terrestrial carbon to the deep-sea is comparatively overlooked. Among systems that connect coastal to deep-sea environments, the Congo Submarine Canyon is of particular interest since the canyon head starts 30 km into the Congo River estuary, which delivers ~7 % of the total organic carbon from the world’s rivers. However, carbon and sediment transport mechanisms that operate in the Congo Canyon, and submarine canyons more globally, are poorly constrained compared to rivers because monitoring of deep-sea canyons remains challenging. Using a novel array of acoustic instruments, sediment traps and cores, this study seeks to understand the hydrodynamic processes that control delivery of particulate organic carbon via the Congo Submarine Canyon to the deep-sea. We show that particulate organic carbon transport in the canyon-axis is modulated by two processes. First, we observe periods where the canyon dynamics are dominated by tides, which induce a background oscillatory flow (speeds of up to 0.15 m/s) through the water column, keeping muds in suspension, with a net upslope transport direction. Second, fast-moving (up to 8 m/s) turbidity currents occur for 35 % of the time during monitoring periods and transport both muddy and sandy particulate organic carbon at an estimated transit flux that is more than ten times the flux induced by tides. Remarkably, organic carbon transported and deposited in the submarine canyon has a similar isotopic composition to organic carbon in the Congo River, and in the deep-sea fan at 5 km of water depth. Episodic turbidity currents, together with background tidal currents thus promote efficient transfer of river-derived particulate organic carbon in the Congo Submarine Fan, leading to some of the highest terrestrial carbon preservation rates observed in marine sediments globally.
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- 2024
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11. Leakage of old carbon dioxide from a major river system in the Canadian Arctic
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Dasari, Sanjeev, primary, Garnett, Mark H, additional, and Hilton, Robert G, additional
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- 2024
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12. Seismic cycles, earthquakes, landslides and sediment fluxes: Linking tectonics to surface processes using a reduced-complexity model
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Croissant, Thomas, Steer, Philippe, Lague, Dimitri, Davy, Philippe, Jeandet, Louise, and Hilton, Robert G.
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- 2019
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13. High rates of rock organic carbon oxidation sustained as Andean sediment transits the Amazon foreland-floodplain
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Dellinger, Mathieu, primary, Hilton, Robert G., additional, Baronas, J. Jotautas, additional, Torres, Mark A., additional, Burt, Emily I., additional, Clark, Kasey E., additional, Galy, Valier, additional, Ccahuana Quispe, Adan Julian, additional, and West, A. Joshua, additional
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- 2023
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14. Climate regulates the erosional carbon export from the terrestrial biosphere
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Hilton, Robert G.
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- 2017
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15. Rock organic carbon oxidation CO2 release offsets silicate weathering sink.
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Zondervan, Jesse R., Hilton, Robert G., Dellinger, Mathieu, Clubb, Fiona J., Roylands, Tobias, and Ogrič, Mateja
- Abstract
Mountain uplift and erosion have regulated the balance of carbon between Earth’s interior and atmosphere, where prior focus has been placed on the role of silicate mineral weathering in CO
2 drawdown and its contribution to the stability of Earth’s climate in a habitable state1–5. However, weathering can also release CO2 as rock organic carbon (OCpetro ) is oxidized at the near surface6,7; this important geological CO2 flux has remained poorly constrained3,8. We use the trace element rhenium in combination with a spatial extrapolation model to quantify this flux across global river catchments3,9. We find a CO2 release of 68 − 6 + 18 megatons of carbon annually from weathering of OCpetro in near-surface rocks, rivalling or even exceeding the CO2 drawdown by silicate weathering at the global scale10. Hotspots of CO2 release are found in mountain ranges with high uplift rates exposing fine-grained sedimentary rock, such as the eastern Himalayas, the Rocky Mountains and the Andes. Our results demonstrate that OCpetro is far from inert and causes weathering in regions to be net sources or sinks of CO2 . This raises questions, not yet fully studied, as to how erosion and weathering drive the long-term carbon cycle and contribute to the fine balance of carbon fluxes between the atmosphere, biosphere and lithosphere2,11.Silicate weathering of uplifted rock depletes atmospheric CO2 , but oxidation of revealed rock organic carbon supplies CO2 , offsetting depletion to a degree dependent on regional geological history. [ABSTRACT FROM AUTHOR]- Published
- 2023
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16. Probing the exchange of CO2 and O2 in the shallow critical zone during weathering of marl and black shale
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Roylands, Tobias, Hilton, Robert G., McClymont, Erin L., Garnett, Mark H., Soulet, Guillaume, Klotz, Sébastien, Degler, Mathis, Napoleoni, Felipe, and Bouteiller, Caroline
- Abstract
Chemical weathering of sedimentary rocks can release carbon dioxide (CO2) and consume oxygen (O2) via the oxidation of petrogenic organic carbon and sulfide minerals. These pathways govern Earth’s surface system and climate over geological timescales, but the present-day weathering fluxes and their environmental controls are only partly constrained due to a lack of in situ measurements. Here, we investigate the gaseous exchange of CO2 and O2 during the oxidative weathering of black shales and marls exposed in the French southern Alps. On six fieldtrips over one year, we use drilled headspace chambers to measure the CO2 concentrations in the shallow critical zone, and quantify CO2 fluxes in real-time. Importantly, we develop a new approach to estimate the volume of rock that contributes CO2 to a chamber, and assess effective diffusive gas exchange, by first quantifying the mass of CO2 that is stored in a chamber and connected rock pores. Both rock types are characterized by similar contributing rock volumes and diffusive movement of CO2. However, CO2 emissions differed between the rock types, with yields over rock outcrop surfaces (inferred from the contributing rock volume and the local weathering depths) ranging between 166 tC km-2 yr-1 and 2,416 tC km-2 yr-1 for black shales and between 83 tC km-2 yr-1 and 1,558 tC km-2 yr-1 for marls over the study period. Having quantified diffusive processes, chamber-based O2 concentration measurements are used to calculate O2 fluxes. The rate of O2 consumption increased with production of CO2, and with increased temperature, with an average O2 : CO2 molar ratio of 10 : 1. If O2 consumption occurs by both rock organic carbon oxidation and sulfide oxidation, either an additional O2 sink needs to be identified, or significant export of dissolved inorganic carbon occurs from the weathering zone. Together, our findings refine the tools we have to probe CO2 and O2 exchange in rocks at Earth’s surface and shed new light on CO2 and O2 fluxes, their drivers and the fate of rock-derived carbon.
- Published
- 2023
17. The role of earthquakes and storms in the fluvial export of terrestrial organic carbon along the eastern margin of the Tibetan plateau: A biomarker perspective
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Wang, Jin, primary, Ma, Tian, additional, Zhang, Fei, additional, Hilton, Robert G., additional, Feng, Xiaojuan, additional, and Jin, Zhangdong, additional
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- 2023
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18. Rock organic carbon oxidation CO2release offsets silicate weathering sink
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Zondervan, Jesse R., Hilton, Robert G., Dellinger, Mathieu, Clubb, Fiona J., Roylands, Tobias, and Ogrič, Mateja
- Abstract
Mountain uplift and erosion have regulated the balance of carbon between Earth’s interior and atmosphere, where prior focus has been placed on the role of silicate mineral weathering in CO2drawdown and its contribution to the stability of Earth’s climate in a habitable state1–5. However, weathering can also release CO2as rock organic carbon (OCpetro) is oxidized at the near surface6,7; this important geological CO2flux has remained poorly constrained3,8. We use the trace element rhenium in combination with a spatial extrapolation model to quantify this flux across global river catchments3,9. We find a CO2release of 68−6+18megatons of carbon annually from weathering of OCpetroin near-surface rocks, rivalling or even exceeding the CO2drawdown by silicate weathering at the global scale10. Hotspots of CO2release are found in mountain ranges with high uplift rates exposing fine-grained sedimentary rock, such as the eastern Himalayas, the Rocky Mountains and the Andes. Our results demonstrate that OCpetrois far from inert and causes weathering in regions to be net sources or sinks of CO2. This raises questions, not yet fully studied, as to how erosion and weathering drive the long-term carbon cycle and contribute to the fine balance of carbon fluxes between the atmosphere, biosphere and lithosphere2,11.
- Published
- 2023
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19. New evidence for preservation of contemporary marine organic carbon by iron in Arctic shelf sediments
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Faust, Johan C, primary, Ascough, Philippa, additional, Hilton, Robert G, additional, Stevenson, Mark A, additional, Hendry, Katharine R, additional, and März, Christian, additional
- Published
- 2022
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20. 88. The influence of black shale weathering on riverine Mo isotopes
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Charbonnier, Quentin, Tipper, Edward, Hilton, Robert G., Bouchez, Julien, Gaillardet, Jérôme, Archer, Corey, and Vance, Derek
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ComputingMethodologies_GENERAL - Abstract
Poster presentation
- Published
- 2022
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21. Source versus weathering processes as controls on the Mackenzie river uranium isotope signature
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Charbonnier, Quentin, Clarkson, Matthew O., Hilton, Robert G., and Vance, Derek
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Weathering ,Mackenzie Basin ,Uranium stable isotopes ,Geochemistry and Petrology ,Geology - Abstract
Uranium (U) isotope signatures (δ238U) recorded in sedimentary archives provide insight into the paleo redox state of the ocean. But the robust interpretation of these sedimentary U isotope records requires characterisation of the U isotope signature of rivers, the main source of U to the ocean. The main controlling factors on riverine δ238U remain poorly constrained. Here, we investigate the elemental and isotope signatures of uranium in the dissolved and solid loads of a well-characterised river, the Mackenzie Basin (Canada). In the Mackenzie Basin, the solid load δ238U shows a positive relationship with U and vanadium (V) contents, consistent with the suggestion that particulate δ238U are explained by variable contributions via erosion of silicate and black shale. The δ238U of the dissolved and solid loads are correlated which, at first sight, suggests no U isotope fractionation during chemical weathering, and a purely lithological control on both the river dissolved and solid δ238U. Moreover, relationships between dissolved U and δ238U and major elements such as calcium and sulfate, also support the idea of a lithological control. However, the δ238U of end members inferred from mixing relationships are not consistent with binary mixing of two sources, suggesting some potential U isotope fractionation during weathering. In fact, the abundance of U in the river dissolved load is always lower than that predicted by silicate rock weathering. This suggests that 1) the weathering of silicate only can explain the abundance of U in the river dissolved load and 2) secondary weathering processes scavenge a proportion of the U released by primary mineral breakdown. The broad negative relationship between δ238U and the depletion of dissolved U is also consistent with the control of dissolved δ238U by secondary weathering processes following silicate mineral breakdown. The relationships observed between dissolved U, δ238U and the large-scale environmental controls on weathering processes (such as weathering intensity or runoff) support this hypothesis. Overall, our interpretations of the variation in the river dissolved δ238U challenge the common assumption of the control of dissolved U by black shale and carbonate weathering. In addition, we suggest that the extent of secondary weathering processes can imprint on the U isotope signature of rivers, now and in the past., Chemical Geology, 625, ISSN:0009-2541, ISSN:1872-6836
- Published
- 2023
22. Turbidity currents can dictate organic carbon fluxes across river‐fed fjords: an example from Bute Inlet (BC, Canada)
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Hage, Sophie, Galy, Valier, Cartigny, Matthieu J. B., Heerema, Catharina, Heijnen, Maarten S., Acikalin, Sanem, Clare, Michael A., Giesbrecht, Ian J. W., Grocke, Darren R., Hendry, A., Hilton, Robert G., Hubbard, Stephen M., Hunt, James E., Lintern, D. Gwyn, McGhee, Claire A., Parsons, Daniel R., Pope, Edward L., Stacey, Cooper David, Sumner, Esther J., Tank, Suzanne E., Talling, Peter J., Hage, Sophie, Galy, Valier, Cartigny, Matthieu J. B., Heerema, Catharina, Heijnen, Maarten S., Acikalin, Sanem, Clare, Michael A., Giesbrecht, Ian J. W., Grocke, Darren R., Hendry, A., Hilton, Robert G., Hubbard, Stephen M., Hunt, James E., Lintern, D. Gwyn, McGhee, Claire A., Parsons, Daniel R., Pope, Edward L., Stacey, Cooper David, Sumner, Esther J., Tank, Suzanne E., and Talling, Peter J.
- Abstract
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hage, S., Galy, V., Cartigny, M., Heerema, C., Heijnen, M., Acikalin, S., Clare, M., Giesbrecht, I., Gröcke, D., Hendry, A., Hilton, R., Hubbard, S., Hunt, J., Lintern, D., McGhee, C., Parsons, D., Pope, E., Stacey, C., Sumner, E., Tank, S., & Talling, P. Turbidity currents can dictate organic carbon fluxes across river‐fed fjords: an example from Bute Inlet (BC, Canada). Journal of Geophysical Research: Biogeosciences, 127(6), (2022): e2022JG006824, https://doi.org/10.1029/2022jg006824., The delivery and burial of terrestrial particulate organic carbon (OC) in marine sediments is important to quantify, because this OC is a food resource for benthic communities, and if buried it may lower the concentrations of atmospheric CO2 over geologic timescales. Analysis of sediment cores has previously shown that fjords are hotspots for OC burial. Fjords can contain complex networks of submarine channels formed by seafloor sediment flows, called turbidity currents. However, the burial efficiency and distribution of OC by turbidity currents in river-fed fjords had not been investigated previously. Here, we determine OC distribution and burial efficiency across a turbidity current system within Bute Inlet, a fjord in western Canada. We show that 62% ± 10% of the OC supplied by the two river sources is buried across the fjord surficial (30–200 cm) sediment. The sandy subenvironments (channel and lobe) contain 63% ± 14% of the annual terrestrial OC burial in the fjord. In contrast, the muddy subenvironments (overbank and distal basin) contain the remaining 37% ± 14%. OC in the channel, lobe, and overbank exclusively comprises terrestrial OC sourced from rivers. When normalized by the fjord’s surface area, at least 3 times more terrestrial OC is buried in Bute Inlet, compared to the muddy parts of other fjords previously studied. Although the long-term (>100 years) preservation of this OC is still to be fully understood, turbidity currents in fjords appear to be efficient at storing OC supplied by rivers in their near-surface deposits., S.H. acknowledges funding by the IAS postgraduate grant scheme, a Research Development funds offered by Durham University, and the NOCS/WHOI exchange program. S.H. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 899546. The field campaign and geochemical analyses were supported by Natural Environment Research Council grants NE/M007138/1, NE/W30601/1, NE/N012798/1, NE/K011480/1 and NE/M017540/1. M.J.B.C. was funded by a Royal Society Research Fellowship (DHF\R1\180166). M.A.C. was supported by the U.K. National Capability NERC CLASS program (NE/R015953/1) and NERC grants (NE/P009190/1 and NE/P005780/1). C.J.H. and M.S.H. were funded by the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 721403 - ITN SLATE. E.L.P. was supported by a Leverhulme Early Career Fellowship (ECF-2018-267).
- Published
- 2022
23. Vegetal Undercurrents – Obscured Riverine Dynamics of Plant Debris
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Schwab, Melissa S., Hilton, Robert G., Haghipour, Negar, Baronas, J. Jotautas, and Eglinton, Timothy I.
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Arctic ,suspended sediment ,plant biomarker ,undercurrent ,organic carbon ,radiocarbon - Abstract
Much attention has been focused on fine-grained sediments carried as suspended load in rivers due to their potential to transport, disperse, and preserve organic carbon (OC), while the transfer and fate of OC associated with coarser-grained sediments in fluvial systems have been less extensively studied. Here, sedimentological, geochemical, and biomolecular characteristics of sediments from river depth profiles reveal distinct hydrodynamic behavior for different pools of OC within the Mackenzie River system. Higher radiocarbon (14C) contents, low N/OC ratios, and elevated plant-derived biomarker loadings suggest a systematic transport of submerged vascular plant debris above the active riverbed in large channels both upstream of and within the delta. Subzero temperatures hinder OC degradation promoting the accumulation and waterlogging of plant detritus within the watershed. Once entrained into a channel, sustained flow strength and buoyancy prevent plant debris from settling and keep it suspended in the water column above the riverbed. Helical flow motions within meandering river segments concentrate lithogenic and organic debris near the inner river bends forming a sediment-laden plume. Moving offshore, we observe a lack of discrete, particulate OC in continental shelf sediments, suggesting preferential trapping of coarse debris within deltaic and neritic environments. The delivery of waterlogged plant detritus transport and high sediment loads during the spring flood may reduce oxygen exposure times and microbial decomposition, leading to enhanced sequestration of biospheric OC. Undercurrents enriched in coarse, relatively fresh plant fragments appear to be reoccurring features, highlighting a poorly understood yet significant mechanism operating within the terrestrial carbon cycle., Journal of Geophysical Research: Biogeosciences, 127 (3), ISSN:0148-0227, ISSN:2169-8953, ISSN:2169-8961
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- 2022
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24. Erosion of organic carbon in the arctic as a geological carbon dioxide sink
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Hilton, Robert G., Galy, Valier, Gaillardet, Jerome, Dellinger, Mathieu, Bryant, Charlotte, O'Regan, Matt, Grocke, Darren R., Coxall, Helen, Bouchez, Julien, and Calmels, Damien
- Subjects
Marine sediments ,Soils -- Carbon content ,Carbon dioxide -- Environmental aspects ,Air pollution ,Environmental issues ,Science and technology ,Zoology and wildlife conservation - Abstract
Soils of the northern high latitudes store carbon over millennial timescales (thousands of years) and contain approximately double the carbon stock of the atmosphere (1-3). Warming and associated permafrost thaw can expose soil organic carbon and result in mineralization and carbon dioxide (C[O.sub.2]) release (4-6). However, some of this soil organic carbon may be eroded and transferred to rivers (7-9). If it escapes degradation during river transport and is buried in marine sediments, then it can contribute to a longer-term (more than ten thousand years), geological C[O.sub.2] sink (8-10). Despite this recognition, the erosional flux and fate of particulate organic carbon (POC) in large rivers at high latitudes remains poorly constrained. Here, we quantify the source of POC in the Mackenzie River, the main sediment supplier to the Arctic Ocean (11, 12), and assess its flux and fate. We combine measurements of radiocarbon, stable carbon isotopes and element ratios to correct for rock-derived POC (10, 13, 14). Our samples reveal that the eroded biospheric POC has resided in the basin for millennia, with a mean radiocarbon age of 5,800 ± 800 years, much older than the POC in large tropical rivers (13, 14). From the measured biospheric POC content and variability in annual sediment yield (15), we calculate a biospheric POC flux of [2.2.sup.+1.3.sub.-0.9] teragrams of carbon per year from the Mackenzie River, which is three times the C[O.sub.2] draw down by silicate weathering in this basin (16). Offshore, we find evidence for efficient terrestrial organic carbon burial over the Holocene period, suggesting that erosion of organic carbon-rich, high-latitude soils may result in an important geological C[O.sub.2] sink., Photosynthesis and the production of organic carbon by the terrestrial biosphere (O[C.sub.biosphere]) is a major pathway of atmospheric C[O.sub.2] drawdown. Over millennial timescales, some O[C.sub.biosphere] escapes oxidation and contributes to [...]
- Published
- 2015
25. New evidence for preservation of contemporary marine organic carbon by iron in Arctic shelf sediments.
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Faust, Johan C, Ascough, Philippa, Hilton, Robert G, Stevenson, Mark A, Hendry, Katharine R, and März, Christian
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- 2023
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26. Biogeochemical consequences of a changing Arctic shelf seafloor ecosystem
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März, Christian, primary, Freitas, Felipe S., additional, Faust, Johan C., additional, Godbold, Jasmin A., additional, Henley, Sian F., additional, Tessin, Allyson C., additional, Abbott, Geoffrey D., additional, Airs, Ruth, additional, Arndt, Sandra, additional, Barnes, David K. A., additional, Grange, Laura J., additional, Gray, Neil D., additional, Head, Ian M., additional, Hendry, Katharine R., additional, Hilton, Robert G., additional, Reed, Adam J., additional, Rühl, Saskia, additional, Solan, Martin, additional, Souster, Terri A., additional, Stevenson, Mark A., additional, Tait, Karen, additional, Ward, James, additional, and Widdicombe, Stephen, additional
- Published
- 2021
- Full Text
- View/download PDF
27. Pulsed carbon export from mountains by earthquake-triggered landslides explored in a reduced-complexity model
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Croissant, Thomas, primary, Hilton, Robert G., additional, Li, Gen K., additional, Howarth, Jamie, additional, Wang, Jin, additional, Harvey, Erin L., additional, Steer, Philippe, additional, and Densmore, Alexander L., additional
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- 2021
- Full Text
- View/download PDF
28. Temperature control on CO2 emissions from the weathering of sedimentary rocks
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Soulet, Guillaume, Hilton, Robert G., Garnett, Mark H., Roylands, Tobias, Klotz, Sébastien, Croissant, Thomas, Dellinger, Mathieu, Le Bouteiller, Caroline, Soulet, Guillaume, Hilton, Robert G., Garnett, Mark H., Roylands, Tobias, Klotz, Sébastien, Croissant, Thomas, Dellinger, Mathieu, and Le Bouteiller, Caroline
- Abstract
Sedimentary rocks can release carbon dioxide (CO2) during the weathering of rock organic carbon and sulfide minerals. This sedimentary carbon could act as a feedback on Earth’s climate over millennial to geological timescales, yet the environmental controls on the CO2 release from rocks are poorly constrained. Here, we directly measure CO2 flux from weathering of sedimentary rocks over 2.5 years at the Draix-Bléone Critical Zone Observatory, France. Total CO2 fluxes approached values reported for soil respiration, with radiocarbon analysis confirming the CO2 source from rock organic carbon and carbonate. The measured CO2 fluxes varied seasonally, with summer fluxes five times larger than winter fluxes, and were positively correlated with temperature. The CO2 release from rock organic carbon oxidation increased by a factor of 2.2 when temperature increased by 10 °C. This temperature sensitivity is similar to that of degradation of recent-plant-derived organic matter in soils. Our flux measurements identify sedimentary-rock weathering as a positive feedback to warming, which may have operated throughout Earth’s history to force the surface carbon cycle.
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- 2021
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29. Constraints on the source of reactive phases in sediment from a major Arctic river using neodymium isotopes
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Larkin, Christina S., Piotrowski, Alexander M., Hindshaw, Ruth S., Bayon, Germain, Hilton, Robert G., Baronas, J. Jotautas, Dellinger, Mathieu, Wang, Ruixue, Tipper, Edward T., Larkin, Christina S., Piotrowski, Alexander M., Hindshaw, Ruth S., Bayon, Germain, Hilton, Robert G., Baronas, J. Jotautas, Dellinger, Mathieu, Wang, Ruixue, and Tipper, Edward T.
- Abstract
Riverine suspended particulate matter (SPM) is essential for the delivery of micronutrients such as iron (Fe) to the oceans. SPM is known to consist of multiple phases with differing reactivity, but their role in the delivery of elements to the oceans is poorly constrained. Here we provide new constraints on the source and composition of reactive phases in SPM from the Mackenzie River, the largest sediment source to the Arctic Ocean. Sequential leaching of SPM shows that river sediments contain labile Fe phases. We estimate the labile Fe flux is substantial (0.21(+0.06,-0.05) Tg/yr) by quantifying Fe concentrations in weak leaches of the SPM. The labile Fe phase hosts a considerable amount of rare earth elements (REE), including neodymium (Nd). We demonstrate that the labile Fe phase and dissolved load have radiogenic Nd isotope ratios that are identical within uncertainty, but up to 8 epsilon units distinct from the silicate phase. We interpret this as evidence for dynamic cycling between Fe-oxide phases in SPM and the river water, demonstrating the high reactivity of the labile Fe phase. Nd isotope and elemental molar ratios suggest that a significant amount of labile Fe- and Nd-bearing phases are derived from Fe-oxides within the sedimentary source rock rather than silicate mineral dissolution. Thus, sedimentary rock erosion and weathering provides an important source of labile Fe, manganese (Mn) and by extension potentially other trace metals. Our results imply that both past and future environmental change in the Arctic, such as permafrost thaw, may trigger changes to the supply of reactive trace metals. These results demonstrate that a re-evaluation of sediment reactivity within rivers is required where uplifted sedimentary rocks are present.
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- 2021
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30. Conservative transport of dissolved sulfate across the Rio Madre de Dios floodplain in Peru
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Burt, Emily I., primary, Bill, Markus, additional, Conrad, Mark E., additional, Quispe, Adan Julian Ccahuana, additional, Christensen, John N., additional, Hilton, Robert G., additional, Dellinger, Mathieu, additional, and West, A. Joshua, additional
- Published
- 2021
- Full Text
- View/download PDF
31. Supplementary Figures S1 – S7 from Transformation of organic matter in a Barents Sea sediment profile: coupled geochemical and microbiological processes
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Stevenson, Mark A., Faust, Johan C., Andrade, Luiza L., Freitas, Felipe S., Gray, Neil D., Tait, Karen, Hendry, Katharine R., Hilton, Robert G., Henley, Sian F., Tessin, Allyson, Leary, Peter, Papadaki, Sonia, Ailbe Ford, März, Christian, and Abbott, Geoffrey D.
- Abstract
Map of study location in the Barents Sea, correlations between key geochemical, modeled and measured datasets. PCA axis 1 & 2 scores plotted against depth.
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- 2020
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32. Supplementary Table S1 from Transformation of organic matter in a Barents Sea sediment profile: coupled geochemical and microbiological processes
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Stevenson, Mark A., Faust, Johan C., Andrade, Luiza L., Freitas, Felipe S., Gray, Neil D., Tait, Karen, Hendry, Katharine R., Hilton, Robert G., Henley, Sian F., Tessin, Allyson, Leary, Peter, Papadaki, Sonia, Ailbe Ford, März, Christian, and Abbott, Geoffrey D.
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Summary of analyses and purpose for cores from B15
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- 2020
- Full Text
- View/download PDF
33. Efficient preservation of young terrestrial organic carbon in sandy turbidity-current deposits
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Hage, Sophie, Galy, Valier, Cartigny, Matthieu J. B., Acikalin, Sanem, Clare, Michael A., Grocke, Darren R., Hilton, Robert G., Hunt, James E., Lintern, D. Gwyn, McGhee, C. A., Parsons, Daniel R., Stacey, Cooper David, Sumner, Esther J., Talling, Peter J., Hage, Sophie, Galy, Valier, Cartigny, Matthieu J. B., Acikalin, Sanem, Clare, Michael A., Grocke, Darren R., Hilton, Robert G., Hunt, James E., Lintern, D. Gwyn, McGhee, C. A., Parsons, Daniel R., Stacey, Cooper David, Sumner, Esther J., and Talling, Peter J.
- Abstract
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hage, S., Galy, V. V., Cartigny, M. J. B., Acikalin, S., Clare, M. A., Grocke, D. R., Hilton, R. G., Hunt, J. E., Lintern, D. G., McGhee, C. A., Parsons, D. R., Stacey, C. D., Sumner, E. J., & Talling, P. J. Efficient preservation of young terrestrial organic carbon in sandy turbidity-current deposits. Geology, 48(9), (2020): 882-887, doi:10.1130/G47320.1., Burial of terrestrial biospheric particulate organic carbon in marine sediments removes CO2 from the atmosphere, regulating climate over geologic time scales. Rivers deliver terrestrial organic carbon to the sea, while turbidity currents transport river sediment further offshore. Previous studies have suggested that most organic carbon resides in muddy marine sediment. However, turbidity currents can carry a significant component of coarser sediment, which is commonly assumed to be organic carbon poor. Here, using data from a Canadian fjord, we show that young woody debris can be rapidly buried in sandy layers of turbidity current deposits (turbidites). These layers have organic carbon contents 10× higher than the overlying mud layer, and overall, woody debris makes up >70% of the organic carbon preserved in the deposits. Burial of woody debris in sands overlain by mud caps reduces their exposure to oxygen, increasing organic carbon burial efficiency. Sandy turbidity current channels are common in fjords and the deep sea; hence we suggest that previous global organic carbon burial budgets may have been underestimated., We thank C. Johnson, M. Lardie, A. Gagnon, A. McNichol, and the NOSAMS (National Ocean Sciences Accelerator Mass Spectrometry) team (Woods Hole Oceanographic Institution [WHOI], Massachusetts, USA) for their help with ramped oxidation system and isotopes. We thank the captain and crew of CCGS Vector. Support was provided by UK Natural Environment Research Council (NERC) grants NE/M007138/1 (to Cartigny) and NE/L013142/1 (to Talling), NE/P005780/1 and NE/P009190/1 (to Clare); a Royal Society Research Fellowship (to Cartigny); an International Association of Sedimentologists Postgraduate Grant and National Oceanography Centre Southampton–WHOI exchange program funds (to Hage); an independent study award from WHOI (to Galy); the Climate Linked Atlantic Sector Science (CLASS) program (NERC grant NE/R015953/1); and the European Research Council under the European Union’s Horizon 2020 research and innovation program (Grant 725955, to Parsons). We thank François Baudin, Xingqian Cui, editor James Schmitt, and three anonymous reviewers.
- Published
- 2020
34. Global silicate weathering flux overestimated because of sediment–water cation exchange
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Tipper, Edward T., primary, Stevenson, Emily I., additional, Alcock, Victoria, additional, Knight, Alasdair C. G., additional, Baronas, J. Jotautas, additional, Hilton, Robert G., additional, Bickle, Mike J., additional, Larkin, Christina S., additional, Feng, Linshu, additional, Relph, Katy E., additional, and Hughes, Genevieve, additional
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- 2020
- Full Text
- View/download PDF
35. An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers
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Schwab, Melissa S., primary, Hilton, Robert G., additional, Raymond, Peter A., additional, Haghipour, Negar, additional, Amos, Edwin, additional, Tank, Suzanne E., additional, Holmes, Robert M., additional, Tipper, Edward T., additional, and Eglinton, Timothy I., additional
- Published
- 2020
- Full Text
- View/download PDF
36. Long-term patterns of hillslope erosion by earthquake-induced landslides shape mountain landscapes
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Wang, Jin, primary, Howarth, Jamie D., additional, McClymont, Erin L., additional, Densmore, Alexander L., additional, Fitzsimons, Sean J., additional, Croissant, Thomas, additional, Gröcke, Darren R., additional, West, Martin D., additional, Harvey, Erin L., additional, Frith, Nicole V., additional, Garnett, Mark H., additional, and Hilton, Robert G., additional
- Published
- 2020
- Full Text
- View/download PDF
37. Reply to comment by Thomas M. Blattmann on “Carbon dioxide emissions by rock organic carbon oxidation and the next geochemical carbon budget of the Mackenzie River Basin”, v. 319, n. 6, p. 473–499.
- Author
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Horan, Kate, primary, Hilton, Robert G., additional, Dellinger, Mathieu, additional, Tipper, Ed, additional, Galy, Valier, additional, Calmels, Damien, additional, Selby, David, additional, Gaillardet, Jérôme, additional, Ottley, Chris J., additional, Parsons, Daniel R., additional, and Burton, Kevin W., additional
- Published
- 2019
- Full Text
- View/download PDF
38. Technical note : in situ measurement of flux and isotopic composition of CO2 released during oxidative weathering of sedimentary rocks
- Author
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Soulet, Guillaume, Hilton, Robert G., Garnett, Mark H., Dellinger, Mathieu, Croissant, Thomas, Ogrič, Mateja, Klotz, Sébastien, DURHAM UNIVERSITY GBR, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), NERC CENTRE FOR ECOLOGY AND HYDROLOGY GLASGOW GBR, Erosion torrentielle neige et avalanches (UR ETGR (ETNA)), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), and Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
- Subjects
lcsh:Geology ,lcsh:QH501-531 ,lcsh:QH540-549.5 ,lcsh:QE1-996.5 ,[SDE]Environmental Sciences ,lcsh:Life ,lcsh:Ecology - Abstract
Oxidative weathering of sedimentary rocks can release carbon dioxide (CO2) to the atmosphere and is an important natural CO2 emission. Two mechanisms operate – the oxidation of sedimentary organic matter and the dissolution of carbonate minerals by sulfuric acid. It has proved difficult to directly measure the rates at which CO2 is emitted in response to these weathering processes in the field, with previous work generally using methods which track the dissolved products of these reactions in rivers. Here we design a chamber method to measure CO2 production during the oxidative weathering of shale bedrock, which can be applied in erosive environments where rocks are exposed frequently to the atmosphere. The chamber is drilled directly into the rock face and has a high surface-area-to-volume ratio which benefits measurement of CO2 fluxes. It is a relatively low-cost method and provides a long-lived chamber (several months or more). To partition the measured CO2 fluxes and the source of CO2, we use zeolite molecular sieves to trap CO2 “actively” (over several hours) or “passively” (over a period of months). The approaches produce comparable results, with the trapped CO2 having a radiocarbon activity (fraction modern, Fm) ranging from Fm = 0.05 to Fm = 0.06 and demonstrating relatively little contamination from local atmospheric CO2 (Fm = 1.01). We use stable carbon isotopes of the trapped CO2 to partition between an organic and inorganic carbon source. The measured fluxes of rock-derived organic matter oxidation (171 ± 5 mgC m−2 day−1) and carbonate dissolution by sulfuric acid (534±16 mgC m−2 day−1) from a single chamber were high when compared to the annual flux estimates derived from using dissolved river chemistry in rivers around the world. The high oxidative weathering fluxes are consistent with the high erosion rate of the study region. We propose that our in situ method has the potential to be more widely deployed to directly measure CO2 fluxes during the oxidative weathering of sedimentary rocks, allowing for the spatial and temporal variability in these fluxes to be determined.
- Published
- 2018
39. Monsoonal control on a delayed response of sedimentation to the 2008 Wenchuan earthquake
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Zhang, Fei, primary, Jin, Zhangdong, additional, West, A. Joshua, additional, An, Zhisheng, additional, Hilton, Robert G., additional, Wang, Jin, additional, Li, Gen, additional, Densmore, Alexander L., additional, Yu, Jimin, additional, Qiang, Xiaoke, additional, Sun, Youbin, additional, Li, Liangbo, additional, Gou, Longfei, additional, Xu, Yang, additional, Xu, Xinwen, additional, Liu, Xingxing, additional, Pan, Yanhui, additional, and You, Chen-Feng, additional
- Published
- 2019
- Full Text
- View/download PDF
40. Carbon dioxide emissions by rock organic carbon oxidation and the net geochemical carbon budget of the Mackenzie River Basin
- Author
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Horan, Kate, primary, Hilton, Robert G., additional, Dellinger, Mathieu, additional, Tipper, Ed, additional, Galy, Valier, additional, Calmels, Damien, additional, Selby, David, additional, Gaillardet, JérÔme, additional, Ottley, Chris J., additional, Parsons, Daniel R., additional, and Burton, Kevin W., additional
- Published
- 2019
- Full Text
- View/download PDF
41. Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils
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Hemingway, Jordon D., Hilton, Robert G., Hovius, Niels, Eglinton, Timothy I., Haghipour, Negar, Wacker, Lukas, Chen, Meng-Chiang, Galy, Valier, Hemingway, Jordon D., Hilton, Robert G., Hovius, Niels, Eglinton, Timothy I., Haghipour, Negar, Wacker, Lukas, Chen, Meng-Chiang, and Galy, Valier
- Abstract
Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Science 360 (2018): 209-212, doi:10.1126/science.aao6463., Lithospheric organic carbon (“petrogenic”; OCpetro) is oxidized during exhumation and subsequent erosion within mountain ranges. This process is a significant source of CO2 to the atmosphere over geologic timescales, but the mechanisms that govern oxidation rates in mountain landscapes remain poorly constrained. We demonstrate that, on average, 67 ± 11 % of OCpetro initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized within soils, leading to CO2 emissions of 6.1 – 18.6 t C km-2 yr-1. The molecular and isotopic evolution of bulk OC and lipid biomarkers during soil formation reveals that OCpetro remineralization is microbially mediated. Rapid oxidation in mountain soils drives CO2 emissions fluxes that increase with erosion rate, thereby counteracting CO2 drawdown by silicate weathering and biospheric OC burial., This research was supported by: the NSF Graduate Research Fellowship Number 2012126152 and the WHOI Ocean Ventures Fund (J.D.H.); European Research Council Starting Grant 678779 ROC-CO2 (R.G.H.); NSF grants OCE-0851015 and OCE-0928582 and WHOI Independent Study Award 27005306 (V.V.G.).
- Published
- 2018
42. Mountain glaciation drives rapid oxidation of rock-bound organic carbon
- Author
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Horan, Kate, primary, Hilton, Robert G., additional, Selby, David, additional, Ottley, Chris J., additional, Gröcke, Darren R., additional, Hicks, Murray, additional, and Burton, Kevin W., additional
- Published
- 2017
- Full Text
- View/download PDF
43. Geological respiration of a mountain belt revealed by the trace element rhenium
- Author
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Hilton, Robert G., Gaillardet, Jérôme, Calmels, Damien, Birck, Jean-Louis, Department of Geography, Durham University, Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Department of Earth Sciences [Cambridge, UK], University of Cambridge [UK] (CAM), and Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Geophysics ,Space and Planetary Science ,Geochemistry and Petrology ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,organic carbon ,mountain rivers ,carbon cycle ,Earth and Planetary Sciences (miscellaneous) ,weathering ,rhenium ,erosion - Abstract
International audience; Oxidation of rock-derived, petrogenic, organic carbon (OC petro) during weathering of sedimentary rocks is a major source of carbon dioxide (CO 2) to the atmosphere. This geological respiration is thought to be enhanced by physical erosion, suggesting that mountain belts could release large amounts of CO 2 to counter the CO 2 sequestration achieved by the erosion, riverine transfer and oceanic burial of organic carbon from the terrestrial biosphere. However, OC petro oxidation rates in mountain belts have not been quantified. Here we use rhenium (Re) as a proxy to track OC petro oxidation in mountain river catchments of Taiwan, where existing measurements of physical erosion rate allow the controls on OC petro oxidation to be assessed. Re has been shown to be closely associated with OC petro in rocks and following oxidation during chemical weathering forms a soluble oxyanion (ReO − 4) which contributes to the dissolved load of rivers. Soils on meta-sedimentary rocks in Taiwan show that Re loss is coupled to OC petro loss during weathering, confirming previous observations from soil profiles on sedimentary rocks elsewhere. In Taiwan rivers, dissolved Re flux increases with the catchment-average sediment yield, suggesting that physical erosion rate is a major control on OC petro oxidation. Based on our current understanding of Re mobility during weathering, the dissolved Re flux can be used to quantify an upper bound on the OC petro oxidation rate and the associated CO 2 transfer. The estimated CO 2 release from this mountain belt by OC petro oxidation does not negate estimates of CO 2 sequestration by burial of biospheric OC offshore. The findings are compared to OC transfers estimated for the Himalaya, where OC petro oxidation in the mountain belt remains unconstrained. Together, these cases suggest that mountain building in the tropics can result in a net sink of OC which sequesters atmospheric CO 2.
- Published
- 2014
44. Earthquake-triggered increase in biospheric carbon export from a mountain belt
- Author
-
Wang, Jin, primary, Jin, Zhangdong, additional, Hilton, Robert G., additional, Zhang, Fei, additional, Li, Gen, additional, Densmore, Alexander L., additional, Gröcke, Darren R., additional, Xu, Xiaomei, additional, and West, A. Joshua, additional
- Published
- 2016
- Full Text
- View/download PDF
45. Decadal carbon discharge by a mountain stream is dominated by coarse organic matter
- Author
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Turowski, Jens M., primary, Hilton, Robert G., additional, and Sparkes, Robert, additional
- Published
- 2015
- Full Text
- View/download PDF
46. Seismically enhanced solute fluxes in the Yangtze River headwaters following the A.D. 2008 Wenchuan earthquake
- Author
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Jin, Zhangdong, primary, West, A. Joshua, additional, Zhang, Fei, additional, An, Zhisheng, additional, Hilton, Robert G., additional, Yu, Jimin, additional, Wang, Jin, additional, Li, Gen, additional, Deng, Li, additional, and Wang, Xulong, additional
- Published
- 2015
- Full Text
- View/download PDF
47. Technical note: In situ measurement of flux and isotopic composition of CO2 released during oxidative weathering of sedimentary rocks.
- Author
-
Soulet, Guillaume, Hilton, Robert G., Garnett, Mark H., Dellinger, Mathieu, Croissant, Thomas, Ogrič, Mateja, and Klotz, Sébastien
- Subjects
SEDIMENTARY rocks ,CARBON dioxide ,ATMOSPHERE ,SULFURIC acid ,WEATHERING ,ZEOLITES - Abstract
Oxidative weathering of sedimentary rocks can release carbon dioxide (CO
2 ) to the atmosphere and is an important natural CO2 emission. Two mechanisms operate -- the oxidation of sedimentary organic matter and the dissolution of carbonate minerals by sulfuric acid. It has proved difficult to directly measure the rates at which CO2 is emitted in response to these weathering processes in the field, with previous work generally using methods which track the dissolved products of these reactions in rivers. Here we design a chamber method to measure CO2 production during the oxidative weathering of shale bedrock, which can be applied in erosive environments where rocks are exposed frequently to the atmosphere. The chamber is drilled directly into the rock face and has a high surface-area-to-volume ratio which benefits measurement of CO2 fluxes. It is a relatively low-cost method and provides a long-lived chamber (several months or more). To partition the measured CO2 fluxes and the source of CO2 , we use zeolite molecular sieves to trap CO2 "actively" (over several hours) or "passively" (over a period of months). The approaches produce comparable results, with the trapped CO2 having a radiocarbon activity (fraction modern, Fm) ranging from FmD0.05 to FmD 0.06 and demonstrating relatively little contamination from local atmospheric CO2 (FmD1.01). We use stable carbon isotopes of the trapped CO2 to partition between an organic and inorganic carbon source. The measured fluxes of rockderived organic matter oxidation (171-5 mgCm river chemistry in rivers around the world. The high oxidative weathering fluxes are consistent with the high erosion rate of the study region. We propose that our in situ method has the potential to be more widely deployed to directly measure CO2 fluxes during the oxidative weathering of sedimentary rocks, allowing for the spatial and temporal variability in these fluxes to be determined. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
48. Technical note: in situ measurement of flux and isotopic composition of CO2 released during oxidative weathering of sedimentary rocks.
- Author
-
Soulet, Guillaume, Hilton, Robert G., Garnett, Mark H., Dellinger, Mathieu, Croissant, Thomas, Ogrič, Mateja, and Klotz, Sébastien
- Subjects
WEATHERING ,CARBON dioxide ,EMISSIONS (Air pollution) ,SULFURIC acid ,ROCKS - Abstract
Oxidative weathering of sedimentary rocks can release carbon dioxide (CO
2 ) to the atmosphere and is an important natural CO2 emission. Two mechanisms operate - the oxidation of sedimentary organic matter and the dissolution of carbonate minerals by sulphuric acid. It has proved difficult to directly measure the rates of these weathering processes in the field, with previous work generally using indirect methods which track the dissolved products of these reactions in rivers. Here we design a chamber method to measure CO2 production during the oxidative weathering of shale bedrock, which can be applied in erosive environments where rocks are exposed frequently to the atmosphere. The chamber is drilled directly into the rock face and is a relatively low cost method to provide a long-lived (several months or more), oxygenated environment in contact with a surface area of potential reactant. To partition the measured CO2 fluxes and the source of CO2 , we use zeolite molecular sieves to trap CO2 actively
(over several hours) orpassively
(over a period of months). The approaches produce comparable results, with the trapped CO2 having a fraction modern ranging from 0.05 to 0.06 and demonstrating relatively little contamination from local atmospheric CO2 (fraction modern of 1.01). We use stable isotopes of the trapped CO2 to partition between an organic and inorganic carbon source. The measured fluxes of rock-derived organic matter oxidation and carbonate dissolution by sulphuric acid from a single chamber were high, but consistent with the high erosion rate of the study region (of ~ 5 mm yr-1 ). We propose our in situ method has the potential to be more widely deployed to directly measure CO2 fluxes during the oxidative weathering of sedimentary rocks, allowing for the spatial and temporal variability in these fluxes to be determined. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
49. Controls on fluvial evacuation of sediment from earthquake-triggered landslides
- Author
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Wang, Jin, primary, Jin, Zhangdong, additional, Hilton, Robert G., additional, Zhang, Fei, additional, Densmore, Alexander L., additional, Li, Gen, additional, and West, A. Joshua, additional
- Published
- 2015
- Full Text
- View/download PDF
50. Decadal carbon discharge by a mountain stream is dominated by coarse organic matter.
- Author
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Turowski, Jens M., Hilton, Robert G., and Sparkes, Robert
- Subjects
- *
EROSION , *PARTICULATE matter , *BIOSPHERE , *ATMOSPHERIC carbon dioxide , *FLOODS , *SEDIMENTS - Abstract
Rapid erosion in mountain forests results in high rates of biospheric particulate organic carbon (POC) export by rivers, which can contribute to atmospheric carbon dioxide drawdown. However, coarse POC (CPOC) carried by particles >~1 mm is rarely quantified. In a forested pre-Alpine catchment, we measured CPOC transport rates and found that they increase more rapidly with water discharge than fine POC (<1 mm) and dissolved organic carbon (DOC). As a result, decadal estimates of CPOC yield of 12.3 ± 1.9 t C km^yr"1 are higher than for fine POC and DOC, even when excluding 4 extreme flood events. When including these floods, CPOC dominates organic carbon discharge (~80%). Most CPOC (69%) was water logged and denser than water, suggesting that CPOC has the potential to contribute to long-term sedimentary burial. Global fluxes remain poorly constrained, but if the transport behavior of CPOC shown here is common to other mountain streams and rivers, then neglecting CPOC discharge could lead to a large underestimation of the global transfer of biospheric POC from land to ocean. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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