0000000001239550
AUTHOR
Christophe Colin
A global palaeoclimatic reconstruction for the Valanginian based on clay mineralogical and geochemical data
International audience; High-resolution clay mineral and δ18Ocarb analyses have been performed on three sections of Valanginian age (Early Cretaceous), from northwestern (~20–30°N) and southern (~53°S) Tethyan realms. The data have been integrated in a large set of published mineralogical (clays), and geochemical (δ18Ocarb, δ18Obivalve, δ18Olenticulina, δ18Obelemnite, and TEX86) data from 17 sections, situated between ~45°N and ~53°S. Based on this data set, we provide new insights into Valanginian climate conditions from a wide range of palaeolatitudes. We highlight climate trends within specific areas and identify main climate belts. In the Proto-North Atlantic realm (~15–17°N) large amou…
The large-scale evolution of neodymium isotopic composition in the global modern and Holocene ocean revealed from seawater data and other records
International audience; The large-scale evolution of neodymium isotopic composition in the global modern and Holocene ocean revealed from seawater data and other records. Kazuyo Tachikawa and project members Neodymium isotopic compositions (143 Nd/ 144 Nd or ε Nd) have been used as a tracer of water masses and lithogenic inputs to the ocean. To further evaluate the faithfulness of this tracer, we have updated a global seawater ε Nd database and combined it with hydrography parameters (temperature, salinity, nutrients and oxygen concentrations), carbon isotopic ratio and radiocarbon of dissolved inorganic carbon. Archive ε Nd data are compiled for leachates, foraminiferal tests, deep-sea cor…