Christopher Day

Christopher Day

Research Fellow in Stable Isotopes
Tel: +44 (0) 1865 272044

I am an isotope geochemist researching palaeoclimate and environmental reconstruction.

Proxy development:

A significant amount of my research is developing and calibrating proxies for environmental change, using cave stalagmite samples.

Stalagmite measurements add significantly to the more traditional marine- and ice-core records. They provide extremely high resolution records of e.g. the hydrological cycle (monthly in certain cases), are well preserved, don’t melt (!) and can be dated in absolute terms using U-Th or U-Pb dating.

To make best use of stalagmite archives we need to calibrate the response of their chemistry to environmental change. To achieve this, I built a laboratory setup for growing carbonate crystals in controlled, cave-analogue conditions – the ‘Oxford Cave’. Some of my past work was calibrating the response of e.g. O, C, Ca, Mg, Ba, Sr, Cd to changes in rainfall amount and temperature.

Research is also ongoing with less traditional proxies , (e.g. clumped isotopes, Li-isotopes) to further develop our understanding of these systems and to widen the scope for environmental reconstruction (e.g. weathering intensity).

Palaeoclimate reconstruction:

With students and collaborators, knowledge from the Oxford Cave is applied to palaeoclimate reconstruction projects in e.g. Morocco, Southern Chile, China. We demonstrate, amongst others, the use of Cd as a sensitive proxy for changes in rainfall amount and the application of Ca isotopes for reconstructing absolute change in rainfall amount during abrupt climate change events.

CaveCalc by Dr. Robert Owen:

CaveCalc is a numerical forward-model for speleothem and dripwater chemistry written by Dr. Robert Owen. Proxies modelled include carbon isotopes (stable and radiocarbon), oxygen isotopes, calcium isotopes and trace metals. Processes include bedrock dissolution, carbon dioxide degassing and calcite precipitation. CaveCalc can explicitly model semi-open system bedrock dissolution. It is based on PHREEQC, and may be readily expanded in future. It is currently in review with  the journal Computers and Geosciences. More links and information will become available here.

Stable Isotope Laboratory management:

My research runs alongside managing the department Stable Isotope laboratory, a central hub for research into oceanic, terrestrial, hydrological and carbon cycles. Both sides of my role complement each other, with a vested interest in continually improving the capability of the Stable Isotope laboratory to best serve our research interests.

 

Please do contact me by e-mail with any questions regarding laboratory or research interests.

  • R.A. Owen, C.C. Day et al., Calcium isotopes in caves as a proxy for aridity: modern calibration and appli- cation to the 8.2 kyr event (2016), Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2016.03.027
  • Philp Wulff, C.C.Day, Frank Sargent, Fraser A. Armstrong, How oxygen reacts with oxygen-tolerant respiratory [NiFe]-hydrogenases (2014), Proceedings of the National Academy of Science, DOI: 10.1073/pnas.1322393111
  • Day, C.C. and Henderson, G.M. Controls on trace-element partitioning in cave-analogue calcite (2013)Geochimica et Cosmochimica Acta, DOI:10.1016/j.gca.2013.05.044.
  • Day, C.C. and Henderson, G.M. Response to comment on Day and Henderson “Oxygen isotopes in calcitegrown under cave-analogue conditions”. Geochimica and Cosmochimica Acta. 85 (2012), pp. 388-389.DOI:10.1016/DI.gca.2012.02.026
  • Day, C.C. and Henderson, G.M. Oxygen isotopes in calcite grown under cave-analogue conditions (2011)Geochimica et Cosmochimica Acta, 75 (14), pp. 3956-3972. DOI: 10.1016/DI.gca.2011.04.026
  • Reynard, L.M., Day, C.C., Henderson, G.M. Large fractionation of calcium isotopes during cave-analogue calcium carbonate growth (2011) Geochimica et Cosmochimica Acta, 75 (13), pp. 3726-3740. doi:10.1016/j.gca.2011.04.010