Protactinium dating

Cheng H, Edwards RL, Murrell MT, Goldstein S (1998) The systematics of uranium-thorium-protactinium dating. Geochim Cosmochim Acta 62(21) 3437-3452... 

Cheng H, Edwards RL, Mttrrell MT, Benjamin TM (1998) Uranium-thorittm-protactinium dating systematics. Geochim Cosmochim Acta 62 3437-3452 Cherdyntsev W, Kazachevskii IV, Kttz mina YA (1965) Age of carbonate determined from the isotopes of thorium and uranium. Geochem Int 2 749-756... 

Cheng, H., Edwards, R.L., Murrell, M.T. and Benjamin, T.M., 1998. Uranium-thorium-protactinium dating systematics. Geochim. Cosmochim. Acta, 62 3437-3452. Holmes, A., 1946. An estimate of the age of the Earth. Nature, 157 680-684. 

Cheng H., Edwards R. L., Murrell M. T., and Benjamin T. M. (1998) Uranium—thorium-protactinium dating systema-tics. Geochim. Cosmochim. Acta 62, 3437-3452. 

Edwards RL, Cheng H, Murrell MT, Goldstein SJ (1997) Protactinium-231 dating of carbonates by thermal ionization mass spectrometiy imphcations for Quaternary climate change. Science 276 782-785... 

Figure 1. Schematic diagram showing a TRU-spec extraction chromatography method for separation of uranium, thorium, protactinium, and radium from a single rock aliquot. Further purification for each element is normally necessary for mass spectrometric analysis. Analysis of a single aliquot reduces sample size requirements and facilitates evaluation of uranium-series dating concordance for volcanic rocks and carbonates. For TIMS work where ionization is negatively influenced by the presence of residual extractant, inert beads are used to help remove dissolved extractant from the eluant.

Ku T-L (1968) Protactinium-231 method of dating coral from Barbados Island. J Geophys Res 73 2271-2276... 

Edmonds HN, Moran SB, Hoff JA, Smith JN, Edwards RL (1998) Protactinium-231 and Thorium-230 abundances and high scavenging rates in the Western Arctic ocean. Science 280 405-407 Edwards RL, Gallup CD, Cheng H (2003) Uranium-series dating of marine and lacustrine carbonates. Rev Mineral Geochem 52 363-405... 

Sarma, T. P., Dating of Marine Sediments by Ionium and Protactinium Methods, PhD Thesis, Carnegie Institute of Technology, Pittsburgh, Pennsylvania (1965). 

It was first identified and named brevium, meaning brief, by Kasimir Fajans and O. H. Gohring in 1913 because of its extremely short half-life. In 1918 Otto Hahn (1879—1968) and Lise Meitner (1878-1968) independently discovered a new radioactive element that decayed from uranium into (actinium). Other researchers named it uranium X2. It was not until 1918 that researchers were able to identify independently more of the elements properties and declare it as the new element 91 that was then named protactinium. This is another case in which several researchers may have discovered the same element. Some references continue to give credit for protactinium s discovery to Frederich Soddy (1877—1956) and John A. Cranston (dates unknown), as well as to Hahn and Meitner. 

Direct sea-level reconstruction has been accomplished using a number of different strategies. The main approach has been °Th dating of carbonates that mark or constrain sea level, supplemented in some cases with Pa dating. Protactinium-231 dating provides a critical check on the accuracy of °Th dates. °Th dating has a range from 3 yr to 6 X 10 yr. Therefore, in principle, this method can be used to reconstruct... 

Protactinium-231 dating is based on the initial portion of the decay chain. 

Actually, all elements heavier than lead and bismuth are radioactive and are constantly disintegrating. Eventually, lead and bismuth will be the heaviest natural elements on earth, for the heavier elements—polonium, radon, radium, actinium, thorium, protactinium, and uranium—will have disappeared at some date in the distant future. 

Element 43 technetium (Tc, discovered 1939) 61, promethium (Pm, 1945) 75, rhenium (Re, 1925) 85, astatine (At, 1940) 87, francium (Fr, 1939). Lewis book was quite up-to-date— Hafnium (Hf) was discovered in 1923, the year White Lightning was published, and one can imagine the author happily updating the title of Chapter 72 in the galley proofs. Chapter 86 is titled Niton (now Radon) Chapter 91 is titled Brevium (now Protactinium). For a brief table on the discovery of the chemical elements, see A.J. Ihde, The Development of Modern Chemistry, Harper Row, New York, 1964, pp. 747-749. 

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