Geochemical decoupling of water masses in the Variscan oceanic system during Late Devonian times

Nd isotopic composition of Late Devonian seawater in western Thailand: Geotectonic implications for the origin of the Sibumasu terrane

“…The Paleozoic oceans exhibited a similar Nd isotopic composition to that of the modern ones (e.g., Keto and Jacobsen, 1988;Holmden et al, 1996;Felitsyn et al, 1998;Dopieralska et al, 2006). Hence, reservoirs with a strong non-radiogenic composition of seawater could occur only in very proximal paleoceanographic settings and within epicontinental seas.…”

“…While numerous studies documenting the Nd isotopic composition of seawater and its circulation patterns were published for the Cenozoic and Mesozoic (e.g., Stille et al, 1996;Thomas et al, 2003;Scher and Martin, 2004;Puceat et al, 2005;Gourlan et al, 2008;Dera et al, 2009), reconstructions from the Paleozoic are still rare (Holmden et al, 1996(Holmden et al, , 1998Felitsyn et al, 1998;Fanton et al, 2002;Dopieralska, 2009). The largest dataset of Nd Paleozoic seawater signatures is available from the Upper Devonian, but it is limited to the Variscan realm in Europe and North Africa (Dopieralska, 2003;Dopieralska et al, 2006). Various sediments preserve ancient seawater Nd chemistry.…”

Nd and Sr isotope compositions in modern and fossil bones – Proxies for vertebrate provenance and taphonomy

“…The Nd isotope compositions of fossil biogenic apatite of fish teeth and conodonts have been used to infer paleoseawater compositions and to trace ocean circulation patterns, an application that is only valid if seawater was indeed the fluid present during early diagenesis of the teeth (e.g., Staudigel et al, 1985;Grandjean et al, 1987;Wright et al, 1987;Grandjean and Albarède, 1989;Bertram et al, 1992;Grandjean-Lécuyer et al, 1993;Vennemann and Hegner, 1998;Martin and Haley, 2000;Martin and Scher, 2004;Pucéat et al, 2005;Dopieralska et al, 2006;Scher and Martin, 2006;Kocsis et al, 2008Kocsis et al, , 2009). The Nd isotope composition has, however, not been used as a tracer for terrestrial vertebrate fossils.…”

Protracted diagenetic alteration of REE contents in fossil bioapatites: Direct evidence from Lu–Hf isotope systematics

“…Diagenetically-introduced trace elements have also formed the basis for radiometric dating of bones and teeth in archaeological settings (Millard and Hedges, 1996;Pike et al, 2002). Recently, the Nd isotope compositions of fossil bioapatites have been pivotal in reconstructing the evolution of ocean circulation throughout the Cenozoic (e.g., Vennemann and Hegner, 1998;Martin and Scher, 2004;Thomas, 2004;Martin, 2006, 2008;Via and Thomas, 2006;Kocsis et al, 2009a) and in the Mesozoic (e.g., Stille et al, 1996;Pucéat et al, 2005;Dera et al, 2009) and for Palaeozoic (e.g., Dopieralska et al, 2006;Dopieralska, 2009). Bioapatite-based geochemical proxies depend on two assumptions: (1) REE are introduced into bioapatite (bone and tooth mineral) rapidly after death, and (2) after early diagenetic enrichment, bones and teeth remain closed with respect to REE throughout geological time.…”