caa a22 4500 386384649 CHVBK 20180307112054.0 cr unu---uuuuu 161130s1989 xx s 000 0 eng 10.1017/S0263593300028613 doi S0263593300028613 pii (NATIONALLICENCE)cambridge-10.1017/S0263593300028613 The isotopic geochemistry of ocean waters through time [Elektronische Daten] There is a general consensus that the global chemistry of ocean water has not changed markedly during the Phanerozoic. Nevertheless, significant changes have occurred in the geochemical cycles of some elements and patterns of change have been reconstructed, in various forms, through consideration of the isotope ratios 13C/12C, 34S/32S, 87Sr/86Sr and 143Nd/144Nd. There have also been attempts to constrain variations in the isotopic composition of sea water itself through measurements of D/H and 18O/16O, the latter both directly and indirectly. Dissolved constituents in seawater display secular changes in isotopic composition as a consequence of quite different driving mechanisms. δ13C and δ34S variations are broadly correlated and linked by carbon and sulphur exogenic cycle interaction through redox reactions (the "free oxygen cycle”). The 87Sr/86Sr trend is determined by the balance among different Sr inputs to the oceanic pool, which vary in their isotopic composition (limestones, old granitic material and young basaltic material). Neodymium isotope variations are not globally synchronous. Changes in 143Nd/144Nd are influenced by local erosion products from continental landmasses and can therefore be different for coexisting palaeocean basins. Copyright © Royal Society of Edinburgh 1989 carbon nationallicence neodymium nationallicence oxygen nationallicence strontium nationallicence sulphur nationallicence Fallick A. E. Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 0QU, Scotland, U.K. Hamilton P. J. Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 0QU, Scotland, U.K. Transactions of the Royal Society of Edinburgh: Earth Sciences Royal Society of Edinburgh Scotland Foundation 80/3-4(1989), 177-181 0263-5933 80:3-4<177 1989 80 TRE https://doi.org/10.1017/S0263593300028613 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0263593300028613 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fallick A. E. Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 0QU, Scotland, U.K NATIONALLICENCE 700 1- Hamilton P. J. Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 0QU, Scotland, U.K NATIONALLICENCE 773 0- Transactions of the Royal Society of Edinburgh: Earth Sciences Royal Society of Edinburgh Scotland Foundation 80/3-4(1989), 177-181 0263-5933 80:3-4<177 1989 80 TRE CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge