Reconstruction of Middle and Late Triassic marine palaeotemperatures using oxygen isotopes of conodont apatite

• Applicant: Professor Dr. Michael M. Joachimski
• Subject Area: Palaeontology
• Term: from 2014 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 259132687

The Triassic witnessed a prominent ecological reconfiguration in the aftermath of the Permian-Triassic extinction event. The early Triassic is known as a time period with an extraordinary low diversity. No coal and chert deposits as well as no metazoan reefs are known from this time interval. The major diversification started in the Middle Triassic with e.g. scleractinian corals becoming important reef builders during the Middle and Late Triassic. We were able to show that Early Triassic low-latitudinal paleotemperatures were very warm, potentially exceeding 40° C during certain time intervals. This project is focusing on the compilation of a temperature record for the entire Triassic based on oxygen isotope analyses of conodont apatite phosphate. We intend to study preferentially Middle and Late Triassic sections in Italy and China and to combine these newly generated oxygen isotope data and reconstructed palaeotemperatures with published Early Triassic data. Carbon isotope records based on analyses of carbonates and/or sedimentary organic carbon will be used to document potential changes in the (global) carbon cycle that might be seen in context with palaeoclimate changes. In addition, we will compare the isotope and palaeotemperature records with changes in biodiversity as well as changes in sedimentology (e.g. occurrence of black shales) The Triassic high-resolution temperature record will enable us to address the following key questions: (i) Did the warm house climate prevail throughout the Triassic or did temperatures decrease significantly in the Middle and Late Triassic? If temperatures decreased, how was the temperature evolution in the Middle and Late Triassic? (ii) Is the biotic recovery in the Middle to Late Triassic the consequence of climatic cooling and equable low latitudinal temperatures? (iii) Was the Carnian Pluvial Event a global event and was it associated with noticeable climate changes? We anticipate that the results of this study will contribute to a better understanding of the evolution of the Triassic bio- and geosphere.

• DFG Programme: Research Grants