Séminaire ISTeP - Guillaume Charbonnier

(UNIL)

The Early Cretaceous environmental changes linked to the emplacement of large igneous provinces activity? Mercury data from the Valanginian to Early Aptian sediments.

 The Early Cretaceous period is punctuated by shorter episodes of considerable palaeoceanographic and palaeoenvironmental change.

Intense volcanic activity related to the emplacement of large igneous provinces (LIPs) is considered as an important trigger of oceanic anoxic events (OAEs) and related major environmental change. The establishment of exact temporal relationships between OAE-induced environmental perturbations dated by bio- and chemostratigraphy on one hand and phases of intensified volcanic activity dated by radiometric means on the other hand remains, however, a major challenge. The various stratigraphic time scales currently used have rather confused and smeared the stratigraphic signal, affecting correlations between OAE’s, other episodes of environmental and evolutionary change, and LIP activity. The recent development of mercury (Hg) as a proxy of distal volcanic activity offers the possibility to investigate potential relationships between environmental perturbations and LIP activity in detail. In this talk I will investigate the distribution of mercury contents in different sections in different basins during the Valanginian (Weissert episode) and Early Aptian (OAE1a) episodes to better understand the role of LIPs during the Early Cretaceous.

01/12/2017, Salle Fourcade à 12h30