Earth history; Transition metals; Isotope geochemistry; Ocean chemistry; Biogeochemistry
Wang R.-M., Archer C., Bowie A.R., Vance D. (2019), Zinc and nickel isotopes in seawater from the Indian Sector of the Southern Ocean: The impact of natural iron fertilization versus Southern Ocean hydrography and biogeochemistry, in Chemical Geology
, 511, 452-464.
Andersen M.B., Matthews A., Vance D., Bar-Matthews M., Archer C., de Souza G.F. (2018), A 10-fold decline in the deep Eastern Mediterranean thermohaline overturning circulation during the last interglacial period, in Earth and Planetary Science Letters
, 503, 58-67.
Schlitzer Reiner, Anderson Robert F., Dodas Elena Masferrer, Lohan Maeve, Geibert Walter, Tagliabue Alessandro, Bowie Andrew, Jeandel Catherine, Maldonado Maria T., Landing William M., Cockwell Donna, Abadie Cyril, Abouchami Wafa, Achterberg Eric P., Agather Alison, Aguliar-Islas Ana, van Aken Hendrik M., Andersen Morten, Archer Corey, Auro Maureen, de Baar Hein J., Baars Oliver, Baker Alex R., Bakker Karel, et al. (2018), The GEOTRACES Intermediate Data Product 2017, in Chemical Geology
, 493, 210-223.
Ciscato E.R., Bontognali T.R.R., Vance D. (2018), Nickel and its isotopes in organic-rich sediments: implications for oceanic budgets and a potential record of ancient seawater., in Earth and Planetary Science Letters
, 494, 239-250.
Earth history records fundamental shifts in the character of the planet’s surface environment. A key example is the stepped evolution of the oxygenation state of the surface Earth, from one essentially devoid of molecular oxygen (O2) to the modern surface planet with its O2-rich oceans and atmosphere. In parallel, life on Earth has evolved from single-celled prokaryotic organisms, through the advent of eukaryotes and multi-cellularity, to the complex animals and plants of the modern biosphere. Transitions in the physicochemical character of the surface Earth are often temporally closely associated with revolutions in the biosphere, but cause and effect relationships between the two are hotly debated.The Earth surface chemistry of many transition metals is redox-sensitive so that their abundances in the oceans, for example, are a function of the degree of oxygenation of the surface Earth. Moreover, metals are vital to life, and the availability of specific metals has been suggested to help shape the evolution of the biosphere from the Archean to the present. Redox transitions as well as organismal interactions are accompanied by significant isotope fractionations of these elements. Thus paired records of the abundance and isotopic composition of transition metals in sedimentary rocks have become mainstream tools for the study of the evolution of the surface Earth and its biosphere. The development of metal isotope systems, and their application to the study of Earth history, is one of the core pursuits of the Surface Earth Geochemistry group at ETH Zürich, and we have helped to pioneer this new sub-discipline of isotope geochemistry. This proposal represents a follow-up to two previous SNF projects. Here we seek to continue our effort to develop the transition metal isotope systems into more robust tools, through experiments and observations of modern systems. And we aim to use them to understand two key periods of Earth history that have seen major changes in both the Earth’s environment and its biosphere. We sub-divide the proposal into four sub-projects outlined below.Sub-project A will allow a late-starting PhD student on one of the previous projects to complete. Sub-project B seeks funding for a post-doctoral researcher to continue our fundamental work to characterise isotope fractionations experimentally, and the work on modern processes and cycles that have allowed us to place interpretation of the geological record of transition metals on a sounder footing. Sub-project C would fund a doctoral student to work on a truly remarkable period of Earth history, the Neo-Proterozoic-Phanerozoic transition. Key features of this period is a pulsed and stuttering emergence of the oceans from anoxia, accompanied by profound changes in the biosphere and multiple global glaciations. We argue that cause and effect relationships in this complex transition can only be achieved through a new approach applied at the highest resolution the rock record allows. Sub-project D would fund a doctoral student to work on another of the remarkable periods of Earth history, the late Archean and early Proterozoic, with the primary aim of using a multi-metal isotopic approach to track a hypothesised switch away from an ocean and atmosphere dominated by methanogenic organisms.