I am a geochemist who studies Earth’s past climate using marine and lake sediment cores and speleothems.
Research Area
I am interested in how past climate change affected ancient civilisations, especially the Maya of Mesoamerica. Current projects involve high-resolution speleothem paleoclimatology to reconstruct the climatic context in which the Maya lived (James et al., 2025, Science Advances).
I also study the relationship between changes in Earth’s orbit and the waxing and waning of the great Northern Hemisphere ice sheets during the Quaternary (i.e., the Milankovitch theory of the ice ages). I recently (Oct.-Dec. 2022) led International Ocean Discovery Program (IODP) Expedition 397 to the Iberian Margin off Portugal. We recovered 6.2 km of high-quality core that is ideally suited for studying orbital and millennial climate change since the late Miocene.
I am also interested in analytical method development of palaeoclimatic proxies, especially stable isotopes of hydration water and carbonates. I have links with industrial partners Nu Instruments (Wrexham, UK) and Aerodyne (Boston, USA) who are manufacturers of mass spectrometers and tunable infrared laser direct absorption spectrometers (TILDAS), respectively.
Project Interests
(1) Speleothem Paleoclimatology and the Ancient Maya
An active project involves speleothem palaeoclimatology and cave monitoring in Yucatan, Mexico, during the period of Maya occupation. A 35-cm, annually-laminated stalagmite from Cave Aktun Copo spanning the last 1400 years (~600 C.E.) provides an unprecedented opportunity to reconstruct climate during the Maya late Classic, terminal Classic and Postclassic Periods.
(2) Iberian Margin Palaeoclimate
I welcome projects to study glacial-interglacial cycles of the Quaternary, including the interactions between millennial and orbital climate change and their underlying causes and evolving contextuality. Any projects involving integration of marine, terrestrial and ice core data using the newly recovered cores from IODP Expedition 397 is encouraged. The recent recovery of a 1.5-Ma ice core by the Beyond EPICA-Oldest Ice Project offers exciting opportunities for correlation of Iberian margin sediment and Antarctic ice core records to study the "41-kyr world" and Middle Pleistocene Transition.
(3) Triple oxygen isotopes of CO2
We recently installed an Aerodyne TILDAS Dual Laser CO2 Isotope Analyzer for triple oxygen and carbon isotope analysis of CO2 gas. Several projects involving method development and application of triple oxygen isotope to palaeoclimatic problems are available.
