Johanna Christina Obert


"Systematic investigation of U-series open-system behaviour in fossil reef corals by combined uranium-thorium-protactinium-radium analyses"

Fossil reef corals are an important archive in palaeoclimate research but numerous 230Th/U ages have to be rejected due to open-system behaviour. The processes behind open-system behaviour are still not completely understood.

This PhD thesis aims to improve the accuracy and precision of 230Th/U-dating of fossil reef corals and to gain a better understanding of open-system processes. In the framework of this study, a wide range of samples will be studied with a combination of 238U-234U-230Th analyses with 231Pa/235U and 226Ra/230Th analyses. This approach will yield additional information about open-system processes as well as their timing.

Master thesis:

230Th/U-dating of fossil reef corals from Bonaire, Netherlands Antilles: Comparison of the dating suitability of theca material and bulk material



Peer reviewed:

Brocas, W. M., Felis, T., Obert, J. C., Gierz, P., Lohmann, G., Scholz, D., Kölling, M., and Scheffers, S. R., 2016. Last interglacial temperature seasonality reconstructed from tropical Atlantic corals. Earth and Planetary Science Letters 449, 418-429.


Obert, J.C., Scholz, D., Felis, T., Brocas, W. M., Jochum, K. P., and Andreae, M. O., 2016. 230Th/U dating of Last Interglacial brain corals from Bonaire (southern Caribbean) using bulk and theca wall material. Geochimica et Cosmochimica Acta 178, 20-40.