Geochemistry thorium/uranium

Cochran JK (1984) The fates of U and Th decay series nuclides in the estuarine environment. In The Estuary as a Filter. Kennedy VS (ed) Academic Press, London, p 179-220 Cochran JK (1992) The oceanic chemistry of the uranium - and thorium - series nuclides. In Uranium-series Disequilibrium Applications to Earth, Marine and Environmental Sciences. Ivanovich M, Harmon RS (eds) Clarendon Press, Oxford, p 334-395 Cochran JK, Masque P (2003) Short-lived U/Th-series radionuclides in the ocean tracers for scavenging rates, export fluxes and particle dynamics. Rev Mineral Geochem 52 461-492 Cochran JK, Carey AE, Sholkovitz ER, Surprenant LD (1986) The geochemistry of uranium and thorium in coastal marine-sediments and sediment pore waters. Geochim Cosmochim Acta 50 663-680 Corbett DR, Chanton J, Burnett W, Dillon K, Rutkowski C. (1999) Patterns of groundwater discharge into Florida Bay. Linrnol Oceanogr 44 1045-1055... 

Cochran, J.K., Carey, A., Sholkovitz, E.R., and Surprenant, L.D. (1986) The geochemistry of uranium and thorium in coastal sediments and sediment pore waters. Geochim. Cosmochim. Acta 50, 663-680. 

Surface analytical techniques. A variety of spectroscopic methods have been used to characterize the nature of adsorbed species at the solid-water interface in natural and experimental systems (Brown et al, 1999). Surface spectroscopy techniques such as extended X-ray absorption fine structure spectroscopy (EXAFS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) have been used to characterize complexes of fission products, thorium, uranium, plutonium, and uranium sorbed onto silicates, goethite, clays, and microbes (Chisholm-Brause et al, 1992, 1994 Dent et al, 1992 Combes et al, 1992 Bargar et al, 2000 Brown and Sturchio, 2002). A recent overview of the theory and applications of synchrotron radiation to the analysis of the surfaces of soils, amorphous materials, rocks, and organic matter in low-temperature geochemistry and environmental science can be found in Fenter et al (2002). 

The geochemistry of uranium and thorium has excited considerable interest on accoimt of their strategic importance. Smales determined uranium in rocks by neutron activation followed by isolation of fission product Ba (81). Interference from the fast fission of any thorium present in the sample and from beta-emitting barium isotopes formed by (n,y) reaction is discussed and methods of overcoming the diflSculties are described. The uranium content of two iron meteorites was determined by... 

In this chapter we discuss improvements documented in the literature over the past decade in these areas and others. Chemical procedures, decay-counting spectroscopy, and mass spectrometric techniques published prior to 1992 were previously discussed by Lally (1992), Ivanovich and Murray (1992), and Chen et al. (1992). Because ICPMS methods were not discussed in preceding reviews and have become more commonly used in the past decade, we also include some theoretical discussion of ICPMS techniques and their variants. We also primarily focus our discussion of analytical developments on the longer-lived isotopes of uranium, thorium, protactinium, and radium in the uranium and thorium decay series, as these have been more widely applied in geochemistry and geochronology. 

Martin, J. M., Nijampurkar, V. N., Salvador , F., Uranium and Thorium isotopes behaviour in estuarine systems, In Bio-geochemistry of Estuarine Sediments, Proceedings of Workshop held in Melreux, Belgium, Unesco Pub., 111-127... 

Our knowledge of the geochemistry and mineralogy of Venus surface primarily comes from six types of information (i) elemental analyses of several major elements by X-ray fluorescence (XRF) spectroscopy (ii) analyses of potassium, uranium, and thorium by y-ray spectroscopy ... 

US Environmental Protection Agency (EPA) (1999b) Understanding variation in partition coefficient, Kd, values Volume II. Review of geochemistry and available Kd values for cadmium, cesium, chromium, lead, plutonium, radon, strontium, thorium, tritium (3H) and uranium. Prepared for the EPA by Pacific Northwest National Laboratory. 

The extraction of dates from the uranium and thorium isotope ratios in speleothems depends on a quirk in the geochemistry of these two elements. Uranium is easily oxidized to the state where it usually appears as the U02 ion. The uranyl ion in addition to its intrinsic solubility also forms soluble carbonate complexes that further mobilize the element in karstic ground waters (Langmuir, 1978, 1997). Thorium is firmly locked into the insoluble Th" state and is immobile in ground water (Langmuir... 

Authigenic Deposits. Carbon Cycle. Cenozoic Climate - Oxygen Isotope Evidence. Cenozoic Oceans - Carbon Cycle Models. Cosmogenic Isotopes. Mid-Ocean Ridge Geochemistry and Petrology. Rare Earth Elements and their Isotopes in the Ocean. River Inputs. Stable Carbon Isotope Variations in the Ocean. Uranium-Thorium Series Isotopes in Ocean Profiles. 

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