Experimental constraints on oxygen-free atmospheres
Atmospheric oxygen is fundamental to life as we know it, but its concentration has changed dramatically over Earth’s 4.5 billion year history. An amazing qualitative story has emerged, in which Earth’s atmosphere was devoid of free oxygen for the first 2 billion years of planetary history, with two significant increases in concentration at ~2.4 and ~0.55 billion years ago. Both oxygenation events were accompanied by extreme climatic effects – the “snowball earth” episodes – and paved the way for massive reorganization of biogeochemical cycles such as the Cambrian radiation of macroscopic life. Despite these profound influences on the Earth system, we currently lack fundamental quantitative constraints on Earth’s atmospheric evolution.
In 2016, we plan to start three related PhD projects spanning a wide range of disciplinary backgrounds, offered via Mark’s recent 5 year ~£1.3M European Research Council award entitled “Constraining the evolution of Earth’s atmosphere using novel isotopes and modelling” All projects require a 1st class (or equivalent) undergraduate degree or masters. Additional information detailing the projects is available at http://synergy.st-andrews.ac.uk/earthsci/study/oxygen
This project involves laboratory experiments, analytical geochemistry, and numerical modeling studies of the reducing atmospheric conditions that existed on Earth prior to the Great Oxidation Event (GOE) 2.4 billion years ago.This geochemistry based laboratory project involves interfacing a unique-to-the UK lamp which simulates the young Sun to custom-built chambers which can hold variable gas compositions under different pressures. You will perform experiments under a variety of different gas compositions which are a relevant to the evolution of Earth’s atmosphere prior to the GOE. Using state of the art facilities of the St Andrews Isotope Group, you will measure the quadruple sulfur isotope signatures resulting from your experiments, which can be compared with those seen in the rock record. In conjunction with the PI, you will build a time-dependent numerical model of the atmospheric chemistry occurring in your experimental chamber, with direct application to interpreting your results, and more broadly the evolution of Earth’s atmosphere prior to the Great Oxidation Event.
Suitable Backgrounds for this project include Geology, Geochemistry, or other related natural sciences degrees. Strong Maths skills and previous experience with laboratory methods are strongly desired. Prior programming experience is helpful, but is not a requirement.
Full Funding (tuition + stipend) is only guaranteed for UK/EU students, although exceptional candidates worldwide are encouraged to apply, and any offers would be made at full funding.
More information (and links to references) are available via the above link to http://synergy.st-andrews.ac.uk/earthsci/study/oxygen
How good is research at University of St Andrews in Geography, Environmental Studies and Archaeology?
FTE Category A staff submitted: 36.50
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