PhD project title:
Evolution of marine redox condition and seawater chemistry during Cambrian period
The Cambrian marks a significant interval in Earth history. The system is characterized by the appearance of metazoans bearing mineralized skeletons, and by a rapid diversification of animals commonly referred to as the “Cambrian explosion”. In addition, this was followed by a number of biotic events including evolutionary radiations and extinctions, many of which could be correlated with distinct isotopic excursions in the carbon isotopic curve for this period. Studies suggest that these rises and falls can be attributed to eustatic sea-level history, upwelling of anoxic bottom water onto epicontinental seas, secular change of nutrient cycles and oceanic primary production. Thus, these hypotheses should be tested for understanding the development of Cambrian marine ecosystems.
The aim of my PhD is to look into the marine environment, biogeochemical and nutrient cycling of elements, as well as the role they played in the diversification of animals and biological events during this period. Besides, it is of importance to better undertake stratigraphic correlation worldwide. To contribute to this scientific issue, some geochemical proxies including redox-sensitive elements(RSE) Carbonate-associated sulfate(CAS) Sulfur, Strontium, and Lithium isotopes will be used in my research, combining with solid field observations both in South China and Siberia. RSE and CAS are regarded as powerful proxies material for reconstructing the marine redox condition and primary seawater sulfate sulfur isotope composition while Sr and Li isotopes as useful tracers for understanding the timing and tempo of continental weathering as well as its influence on the marine nutrient cycles.