Sauerstoffisotopie von Conodonten-Apatit zur Rekonstruktion des altpaläozoischen Klimas
Final Report Abstract
Oxygen isotopes of conodont apatite (n = 620) were studied to reconstruct the palaeoclimatic history of the Early Ordovician to Late Silurian. A general cooling trend throughout the Ordovician is followed by a warming trend until the end of the Silurian culminating in the warm Early Devonian. Several short-term warming and cooling (glacial) events are documented for the studied interval. The oxygen isotope record together with evidence from the sedimentary record change our previous understanding of the Early Palaeozoic as a long-lasting greenhouse period interrupted only by the Hirnantian glaciation. Instead, the Early Ordovician to Late Silurian is characterized as a time interval with repeated changes in palaeoclimate and environmental conditions. Our study suggests that climatic cooling may have triggered the Great Ordovician Biodiversification Event (GOBE) representing the ‘explosion of life’ after the Cambrian innovation. Complex ecosystems developed during the Late Ordovician, one of the coldest periods in the Early Palaeozoic, The reef systems flourished in the Ordovician and Silurian at times of climate stability during cold intervals and glaciations. The study only ‘scratched the surface’ and many events during the 70 million years spanning Ordovician need detailed future research to understand the processes initiating macroevolution as well as the establishment of new ecosystems and faunal communities.
