Long-lived thorium isotopes: powerful tools to estimate lithogenic fluxes to the ocean

Hayes and co-workers are back with another rich contribution, based on dissolved 232-thorium (232Th) and 230-thorium (230Th) (click here to access previous highlight from the same author).

The game is to use the fact that both isotopes have readily different sources to the ocean, while both are supposed to be removed by particles. 232Th is lithogenic, therefore introduced by external sources (dust, rivers, etc.), while 230Th is internally produced as decay product of the soluble 234-uranium (234U). Playing with these differences, together with a large set of data on seven water column profiles in the North Pacific, the authors demonstrate that:

  • both tracers can be used to estimate dust fluxes over a given oceanic area. They show that this flux is twice the modelled one in the subarctic part of the section whereas it is more consistent in the subtropics.
  • both tracers are very good proxies for the estimate of boundary exchange processes in deep water along the North Pacific margins which seems to be quite significant in this area.

Hayes 2Figure: Eolian dust fluxes to the North Pacific as estimated from dissolved 232Th-230Th measurements (represented by circles) and from model estimates constrained largely from satellite optical depth (represented by the colormap from Mahowald et al. 2005). The same colour codes have been used for the circles and the colormap.
Click here to see the figure larger.


Hayes, C. T., Anderson, R. F., Fleisher, M. Q., Serno, S., Winckler, G., & Gersonde, R. (2013). Quantifying lithogenic inputs to the North Pacific Ocean using the long-lived thorium isotopes. Earth and Planetary Science Letters, 383, 16–25. DOI: 10.1016/j.epsl.2013.09.025. Click here to access the paper.

Mahowald, N. M., A. R. Baker, G. Bergametti, N. Brooks, R. A. Duce, T. D. Jickells, N. Kubilay, J. M. Prospero, and I. Tegen (2005), Atmospheric global dust cycle and iron inputs to the ocean, Global Biogeochem. Cycles, 19, GB4025, DOI:10.1029/2004GB002402. Click here to access the paper.

Isotopes Atlantic Ocean Iron Global scale Pacific Ocean Neodymium Neodymium isotopes Particles Multiple TEIs Southern Ocean Zinc Thorium Land-ocean inputs Hydrothermal Arctic Ocean Analysis Modelling Circulation Cadmium Land-ocean input Thorium isotopes Data compilation Indian Ocean Cycles Mercury Radium Speciation Barium Silicon Aerosol input Iron isotopes Copper Manganese Hypoxia Radium isotopes Phosphate Cobalt Rare Earth Element Lead Lead isotopes Aluminium Protocol Mediterranean Sea Aerosols Boundary Exchange Protactinium Thorium-Protactinium Paleoceanography Environmental change Organic matter Nepheloids Aerosol Cadmium isotopes Zinc isotopes International Polar Year Uranium Microbial Rare Earth Elements Benthic Limitation Phytoplankton Oxygen Silicon isotopes Chromium Chronium isotopes BioGEOSCAPES Particulate Organic Carbon Export fluxes Residence times Methylmercury Surface waters Helium Paleocirculation Proxy Nickel Remineralization Nitrogen Sediments Climate change Lanthanum Yttrium Scandium Intercalibration Lithogenic Macronutriments Micronutriments Hafnium Hafnium isotopes Ice Sea ice Helium isotopes Particle fluxes Barium isotopes Biological pump Iodine Uranium isotopes Artificial Intelligence Cadmium sulfide Antarctic geology Beryllium Mammals Phosporus Time Series Productivity Red Sea Distribution coefficient Mesoscale transport Fertilisation Processes Estuaries Mesopelagic Anoxia Black Sea ICPMS Ecosystem CO2 degassing Transmissiometer Eddy Kinetic Energy Fate Scavenging Fractionation Distribution Iron sulfide Precipitation Shelf Inputs River Pitzer equations Gadolinium Intercomparison Coastal area Gallium Submarine Ground Water Discharge Cooper isotopes Total Hg Fertilization Experiments Behavior Budget Atmospheric Dynamic SAFE samples Boundary Scavenging Procedure Osmium Arsenic Aerosols input Nitrate Nutrients Deep water Copper isotopes Dissolved concentations

 Data Product (IDP2017)


 Data Assembly Centre (GDAC)


Subscribe Mailing list

Contact us

To get a username and password, please contact the GEOTRACES IPO.

This site uses cookies to offer you a better browsing experience. Find out more on how we use cookies and how you can change your settings.