See methodology and notes (pdf)

Related References:

Andersen, M.B., Stirling, C.H., Zimmermann, B., Halliday, A.N. (2010) Precise determination of the open ocean 234U/238U composition. Geochem. Geophys. Geosyst. 11, Q12003.

Anderson, R.F., Fleisher, M.Q., Robinson, L.F., Edwards, R.L., Hoff, J., Moran, S.B., Rutgers van der Loeff, M.M., Thomas, A.L., Roy-Barman, M., François, R. (2012) GEOTRACES intercalibration of 230Th, 232Th, 231Pa, and prospects for 10Be. Limnol. Oceanogr. Methods 10, 179-213.

Auro ME, LF Robinson, A Burke, LI Bradtmiller, MQ Fleisher, RF Anderson (2012) Improvements to 232-thorium, 230-thorium, and 231-protactinium analysis in seawater arising from GEOTRACES intercalibration Limnology and Oceanography, Methods 10, 464-474

Chen, J.H., Lawrence Edwards, R., Wasserburg, G.J. (1986) 238U, 234U and 232Th in seawater. Earth Planet. Sci. Lett. 80, 241-251.

Cheng, H., Edwards, R.L., Hoff, J., Gallup, C.D., Richards, D.A., and Asmerom, Y. (2000) The half-lives of uranium-234 and thorium-230. Chemical Geology 169, 17-33.

Cheng, H., Edwards, R.L., Shen, C.-C., Polyak, V.J., Asmerom, Y., Woodhead, J., Hellstrom, J., Wang, Y.J., Kong, X.G., Spötl, C., Wang, X.F., and E.Calvin Alexander Jr. (2013) Improvements in 230Th dating, 230Th and 234U half-life values, and U–Th isotopic measurements by multi-collector inductively coupled plasma mass spectrometry. Earth and Planetary Science Letters 371-372, 82-91.

Owens, S.A., Buesseler, K.O., Sims, K.W.W. (2011) Re-evaluating the 238U-salinity relationship in seawater: Implications for the 238U–234Th disequilibrium method. Marine Chemistry 127, 31-39. Rev. Geophys. 33 (2), 241–265.

Roy-Barman, M., Coppola, L. and Souhaut, M. (2002) Thorium isotopes in the western Mediterranean Sea: an insight into the marine particle dynamics. Earth Planet. Sci. Lett. 196, 161-174.

Shen, C.-C., Cheng, H., Edwards, R.L., Thomas, R.B. and Moran, S.B. (2003) Attogram-sized 231Pa Analysis in Dissolved and Particulate fractions of Seawater by Thermal Ionization Mass Spectroscopy. Analytical Chemistry v. 75, issue 5, 1075-1079.

Shen, C.-C., Edwards, R.L., Cheng, H., Dorale, J.A., Thomas, R.B., Moran, S.B., Weinstein, S., and Edmonds, H.N. (2002) Uranium and thorium isotopic and concentration measurements by magnetic sector inductively coupled plasma mass spectrometry. Chemical Geology 185. no. 3-4, 165-178.

Shen, C.C., Wu, C.C., Cheng, H., Edwards, R.L., Hsieh, Y.T., Gallet, S., Chang, C.C., Li, T.Y., Lam, D.D., Kano, A, Hori, M. and Spotl, C. (2012) High-precision and high-resolution carbonate Th-230 dating by MC-ICP-MS with SEM protocols. Geochimica Cosmochim. Acta 99, 71-86. DOI: 10.1016/j.gca.2012.09.018

Taylor, S.R., McLennan, S.M., (1995) The geochemical evolution of the continental crust.

Weyer, S., Anbar, A.D., Gerdes, A., Gordon, G.W., Algeo, T.J., Boyle, E.A. (2008). Natural fractionation of 238U/235U. Geochim. Cosmochim. Acta 72, 345-359.