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E433: A tropical view of late Neoproterozoic glaciation: sedimentary insights from glacial deposits in Rondonia, Brazil (Priority project with CASE partner) (Lead Supervisor: Alexander Liu, Earth Sciences)

Supervisors: Alexander Liu (Earth Sciences), Neil Davies (Earth Sciences) and Milene Figueiredo Freitas (Petrobras)

Importance of the area of research:

The Ediacaran Period (635-541 Ma) witnessed some of the greatest geological and evolutionary events in Earth history, including the rise of oxygen to modern levels, the diversification of animal life, global glaciation events, and large-scale continental readjustments. Determining how biological events such as the appearance of the Ediacaran biota relate to contemporary geological events is a key question for researchers attempting to understand the interplay between Earth and life. Significant questions include what caused the ‘Snowball Earth' glacial events of the late Neoproterozoic, and did their cessation ~580 million years ago play a role in triggering the evolution of the Ediacaran biota? Few global successions document the rocks of early and middle Ediacaran age required to provide answers to these questions, but a new locality in Brazil may provide new insights into early Ediacaran climate change.

Project summary:

This project will investigate a newly recognized Neoproterozoic sedimentary basin in Rondonia, Brazil. The succession includes at least two glacial deposits, and a thick intervening sequence of laminated carbonates. The project will characterize the sedimentology, palaeontology, carbon isotope geochemistry and (if suitable tuffs are identified) age of the section and its glacial units, to inform discussions surrounding global glaciation and its timing relative to biological and geochemical events. This is an excellent opportunity to fully characterize a previously unexplored region with potential importance to global Neoproterozoic research.

What the student will do:

The student will undertake two 4-week field seasons in the Amazon basin, during which time they will produce sedimentary logs of the section at multiple localities; collect specimens for geochemical, petrological, and microfossil analyses; and collect samples of diamictite units to determine the provenance of component clasts. Samples will be analyzed either at the University of Cambridge, or at Petrobras in Brazil, for carbon isotope geochemistry, microfossils, and mineralogical composition. The project aims to determine the likely age of the succession, and permit its correlation with other global localities.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Hoffman, P. F., Kaufman, A. J., Halverson, G. P., & Schrag, D. P. 1998. A Neoproterozoic Snowball Earth. Science, vol. 281, pp. 1342-1346.

Xiao, S., Narbonne, G. M., Zhou, C., Laflamme, M., Grazhdankin, D. V., Moczydłowska-Vidal, M., & Cui, H. 2016. Toward an Ediacaran time scale: Problems, protocols, and prospects. Episodes, vol. 39, pp. 540-555.

Misi, A., Kaufman, A. J., Veizer, J., Powis, K., Azmy, K., Boggiani, P. C., ... & Iyer, S. S. 2007. Chemostratigraphic correlation of Neoproterozoic successions in South America. Chemical Geology, vol. 237, pp. 143-167.

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

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