Biotic, environmental and climatic changes across the Triassic-Jurassic boundary: causes and effects highlighted via the Liassic coral reef associations

The Triassic-Jurassic boundary is considered as one of the five largest mass extinctions of the Phanerozoic. Reef communities, especially corals, suffered high extinction rates. This work focuses on Lower Jurassic corals and coral bioconstructions that lived just after this boundary. The main goal was to study the taxonomic aspects of the corals. Moreover, for better understand the paleoenvironmental conditions of the north-western part of the Tethys during the Triassic-Jurassic crisis, detailed descriptions of outcrops providing coral bioconstructions as well as analyses related to paleotemperatures, paleoecology and paleogeography are presented. The outcrops were studied in distinct localities. They are situated in the Isle of Skye (Scotland), in the Languedoc-Roussillon region (southern France) and in Ardèche (south-eastern France). This work presents also the study of two museum coral collections that are the Lower Jurassic coral collection from the Natural History Museum of London and from the Museum-Aquarium of Nancy