May 12, 2015

Lake Sediments Unlock the Secrets to Past Climate Seasonality

Nick Primmer – University of Nottingham


  • Matthew Jones
  • Sarah Metcalfe
  • Achim Brauer
  • Melanie Leng
  • Phil Barker


Some lakes contain sediment in their beds that has been layered annually or “varved”; this allows layers to be attributed to a specific year like tree layers in dendrochronology. By closely examining their sedimentology the environmental conditions required to create them can be inferred. As a result, past climate can be reconstructed to a sub-annual resolution and hence provide an insight into palaeoseasonality, the change in past climate at a seasonal scale, detail on which is currently lacking. Varves’ robust chronology have the potential to vastly improve the dating of regional environmental change, opening up a new depth of understanding about the palaeoenvironment which can be tied in with other disciplines to improve our understanding of climate and history.


Two varved sediment cores taken from lakes in Turkey and Mexico, named Nar Gölü and Yaal Chac respectively will provide samples for analysis. The high-resolution data will be primarily collected using thin section microscopy and micro X-ray fluorescence (μXRF), which measures the count of heavy elements using X-ray radiation. Thin sections will first be processed into slices at the Helmholtz Centre Potsdam and microscopy will be used to count the varves, measure their thicknesses and identify the composition and structure. The μXRF data will be taken at the University of Aberystwyth, and used to further understand the sediment sources and catchment processes.

Why This Subject Matters to Them

“I have always had a deep interest in the past environment, and how its complex mechanisms can lead to the formation and preservation of a palaeoenvironmental record. I relish the opportunity to decipher the records’ meaning and hence reconstruct the environment to an unprecedented high resolution. Varves have the potential to answer important questions about how these environments change over time and it relationship with anthropogenic activity. Both of my study sites, in Turkey and Mexico, have fascinating histories of cultural development with interesting debates arising about the relationships between humans and nature. Through my research I want to develop the use of varves, help answer some of the key debates about these regions’ past and contribute to the greater knowledge of environmental change.”