Environmental, climatic and biotic changes across the Triassic-Jurassic boundary: causes and effects highlighted via the coral reef associations
supervisors: Rossana Martini, Bernard Lathuilière
collaboration: Université de Nancy
This research is suported by the Swiss National Science Foundation (grant n°200021-130238)
Summary: As for most geological period boundaries, the Triassic-Jurassic (T-J) changeover, about 200 Ma ago, was a critical juncture in Earth history during which profound biotic and environmental changes occurred. At the T-J boundary, after almost 100 Ma of existence, the Pangea supercontinent began a fragmentation that has proceeded to the present day. The most obvious manifestation of this process was the formation of the CAMP (Central Atlantic Magmatic Province), an estimated 2.5 million cubic kilometres of magmatic province. At approximately the same time, profound changes took place in the key elements of the biosphere, most remarkably in the marine carbonate producing organisms. However, processes and causes of biotic and environmental change at the T-J transition still remain controversial. Nevertheless, the idea of a temporary, sudden rise in temperature at that time has been put forward by various authors. Some others proposed a short-term cooling and acidification phase at the end of Triassic probably due to volcanic SO2 impact. The latter was followed by a dramatic “super greenhouse” in the lowermost Jurassic caused by long-term accumulation of volcanic CO2, enhanced by breakdown of biological pumping.Poster) across Luxemburg, some of which have not been published yet (Fig.1).
The project will focus on an integrated study of the T-J boundary, involving sedimentological, palaeontological, palaeoecological and biogeochemical approaches. The results will then be integrated within a depositional model with implementation of detailed depositional-palaeoenvironmental schemes which combine palaeoecological and sedimentological information. We propose that the integration of the palaeoecostratigraphic events to the previously defined sedimentological and stratigraphic framework will allow us to capture climate variability representative of a large area of the western Tethys during the T-J accelerated biotic turnover.