Past climate fluctuations now visible through laser imaging of shells

An international team has developed newly refined techniques for obtaining past climate data from mollusc shells. Mollusc shells are abundant in archaeological sites spanning the last 160,000 years. Using laser imaging, researchers have now found new ways of reconstructing how climate changed during a mollusc’s lifetime, down to the seasonal level. Their technique makes it cheaper and faster to analyze these shells, opening the door to accurately map past climate in coastal areas all over the world.

Shellfish played a significant role in the diet of prehistoric coastal populations, providing valuable nutrients. They are a common find in archaeological sites all over the world, usually in huge numbers, and researchers have long explored how they could be used to make inferences about the environments that humans experienced at those locations in the past. However, although techniques were developed to infer valuable climate-related information from shells, it was previously too expensive to analyse them on a scale beyond individual and isolated records. The current study by an international team of researchers, led by the Institute of Electronic Structure and Laser (Heraklion, Greece) and the School of Geography (Melbourne, Australia) and published in Scientific Reports, presents a technique to use rapid laser imaging to increase the number of analysed shell records to previously unknown scales, and thereby greatly expand the time periods and accuracy of the reconstructed records.

Shells are a common find in archaeological coastal sites of the last 160,000 years

The present study aimed to test a new method by analysing modern shells for which there was known climate data. The researchers used modern limpet shells from across the Mediterranean, comparing records from nine different sites in Greece, Libya, Tunisia, Croatia, Malta, Turkey and Israel. By testing their methods on modern shells against known records, the researchers were able to fine-tune their calibrations and ensure that their techniques would accurately reproduce the climate changes experienced by the molluscs while they were growing. Once perfected, the method could then be used to reconstruct past climate fluctuations.

Source: Vast record of past climate fluctuations now available thanks to laser imaging of shells