Triassischjurassische

Triassischjurassische, often rendered as Triassic–Jurassic in English, is an umbrella term for phenomena, rocks, and fossils related to the boundary between the Triassic and Jurassic periods. This interval, dated to about 201 million years ago, marks a major biotic and climatic shift that reorganized ecosystems worldwide.

Geology and stratigraphy: The boundary is recognized worldwide by a pronounced faunal turnover in marine and terrestrial communities. In rocks deposited near the boundary, many Triassic species disappear while new Early Jurassic taxa appear, particularly among ammonoids, conodonts, and early dinosaurs. The boundary is also associated with isotopic shifts and, in some regions, volcanogenic horizons linked to large igneous province activity.

Causes and drivers: The most widely supported hypothesis attributes the boundary to massive volcanic activity linked to the Central Atlantic Magmatic Province, which would have caused rapid climate warming, atmospheric CO2 increase, ocean anoxia, and sea-level changes that stressed many organisms.

Biological impact: The Triassic–Jurassic extinction event affected a broad range of taxa, reducing diversity and altering communities. The subsequent Jurassic saw the diversification and radiation of dinosaurs, as well as other reptile groups, with the recovery of marine ecosystems taking tens of millions of years.

Classification and use: In geochronology and stratigraphy, the base of the Jurassic (Hettangian stage) is defined at a Global Boundary Stratotype Section and Point (GSSP) in European rocks, with the Triassic–Jurassic boundary used as a reference for cross-continental correlations. The term triassischjurassische appears in German-language geoscience literature to describe this transitional interval.