Supervisors and Institutions
The Early Jurassic (201-174 Myrs ago) represents a time of marked environmental changes and evolution of the Earth system: Climate oscillated between cold and warm modes (Korte and Hesselbo, 2011), seawater chemistry changed substantially (Weldeghebriel et al., 2022) and, along with the evolution of calcifiers, drove changes in the location and mineralogy of carbonate deposition (Ridgwell, 2005; Sandberg, 1983). The carbon cycle underwent several perturbations thought to be driven by volcanism and often associated with the reduced availability of oxygen in the oceans. The interval is bracketed by two well studied events: The end-Triassic extinction and the Toarcian anoxic event, but the intervening period contains several events that have received less attention: The recovery from the end-Triassic extinction in the Hettangian, the Sinemurian-Pliensbachian boundary (SPB) and the end Pliensbachian. Records have mostly focussed on the SPB (e.g. Franceschi et al., 2019) and little work has been done on the long term geochemical record to provide context for these events (with the exception of Han et al., 2022).
The Dinarides of the Adriatic coast contain a continuous record of this time period preserved in platform carbonate deposits. The platform was attached to Gondwana until the mid-Triassic when it started drifting northwards becoming the huge isolated Southern Tethyan Mega-platform. During the Toarcian this broke up to become a complex of smaller platforms separated by deep basins (Vlahović et al., 2005). The aim of this project is to investigate the environmental record of platform carbonate sections in Croatia and their deeper water expression in Montenegro, requiring the integration of field geology, sedimentology, geochemistry and stratigraphy.
The successful candidate will be fully trained in all the necessary techniques. Completing a PhD develops a broad array of transferable skills such as written communication, public speaking, project management, leadership, collaboration and perhaps most importantly, critical thinking. All of the analytical techniques are available in the School’s excellent laboratory facilities. The student will benefit from being part of the Earth Surface Science Institute, and the Cohen Geochemistry and Palaeo@Leeds research groups. This organisational framework provides a broader supportive environment which allows the cross fertilisation of ideas and expertise. In addition to the bespoke training for the PhD, the student will have access to a wide range of other general training and support. Examples would include useful scientific and transferrable skills such as statistics, time management, writing and giving presentations, and skills specific to a PhD programme such as managing your degree and preparing for your viva.
Dodd, M.S., Zhang, Z., Li, C., Algeo, T.J., Lyons, T.W., Hardisty, D.S., Loyd, S.J., Meyer, D.L., Gill, B.C., Shi, W., Wang, W., 2021. Development of carbonate-associated phosphate (CAP) as a proxy for reconstructing ancient ocean phosphate levels. Geochim. Cosmochim. Acta 301, 48–69. https://doi.org/10.1016/j.gca.2021.02.038
Franceschi, M., Corso, J.D., Cobianchi, M., Roghi, G., Penasa, L., Picotti, V., Preto, N., 2019. Tethyan carbonate platform transformations during the Early Jurassic (Sinemurian–Pliensbachian, Southern Alps): Comparison with the Late Triassic Carnian Pluvial Episode. GSA Bull. 131, 1255–1275. https://doi.org/10.1130/B31765.1
Han, Z., Hu, X., He, T., Newton, R.J., Jenkyns, H.C., Jamieson, R.A., Franceschi, M., 2022. Early Jurassic long-term oceanic sulfur-cycle perturbations in the Tibetan Himalaya. Earth Planet. Sci. Lett. 578, 117261. https://doi.org/10.1016/j.epsl.2021.117261
He, T., Newton, R.J., Wignall, P.B., Reid, S., Dal Corso, J., Takahashi, S., Wu, H., Todaro, S., Di Stefano, P., Randazzo, V., Rigo, M., Dunhill, A.M., 2022. Shallow ocean oxygen decline during the end-Triassic mass extinction. Glob. Planet. Change 210, 103770. https://doi.org/10.1016/j.gloplacha.2022.103770
Korte, C., Hesselbo, S.P., 2011. Shallow marine carbon and oxygen isotope and elemental records indicate icehouse-greenhouse cycles during the Early Jurassic. Paleoceanography 26. https://doi.org/10.1029/2011PA002160
Regelous, M., Regelous, A., Grasby, S.E., Bond, D.P.G., Haase, K.M., Gleißner, S., Wignall, P.B., 2020. Tellurium in Late Permian-Early Triassic Sediments as a Proxy for Siberian Flood Basalt Volcanism. Geochem. Geophys. Geosystems 21, e2020GC009064. https://doi.org/10.1029/2020GC009064
Ridgwell, A., 2005. A Mid Mesozoic Revolution in the regulation of ocean chemistry. Mar. Geol. 217, 339. https://doi.org/10.1016/j.margeo.2004.10.036
Sabatino, N., Vlahović, I., Jenkyns, H., Scopelliti, G., Neri, R., Prtoljan, B., Velic, I., 2013. Carbon-isotope record and palaeoenvironmental changes during the early Toarcian oceanic anoxic event in shallow-marine carbonates of the Adriatic Carbonate Platform in Croatia. Geol. Mag. 150, 1085–1102. https://doi.org/10.1017/S0016756813000083
Sandberg, P.A., 1983. An oscillating trend in Phanerozoic non-skeletal carbonate mineralogy. Nature 305, 19–22. https://doi.org/10.1038/305019a0
Vlahović, I., Tišljar, J., Velić, I., Matičec, D., 2005. Evolution of the Adriatic Carbonate Platform: Palaeogeography, main events and depositional dynamics. Palaeogeogr. Palaeoclimatol. Palaeoecol. 220, 333–360. https://doi.org/10.1016/j.palaeo.2005.01.011
Weldeghebriel, M.F., Lowenstein, T.K., García-Veigas, J., Cendón, D.I., 2022. [Ca2+] and [SO42-] in Phanerozoic and terminal Proterozoic seawater from fluid inclusions in halite: The significance of Ca-SO4 crossover points. Earth Planet. Sci. Lett. 594, 117712. https://doi.org/10.1016/j.epsl.2022.117712