Extreme weather events can have profound impacts on society, the economy and the environment. However, the brevity of instrumental data limits our understanding of their mechanism and the evaluation of climate models.

Temporal resolution in traditional paleoclimate studies is typically months or even longer, making it impossible to reveal extreme weather events that occurred on daily to hourly scales.

A research group from the Institute of Earth Environment of the Chinese Academy of Sciences (IEECAS) used land snail shells for the reconstruction of extreme weather conditions. The study was published in Geochimica and Cosmochimica Acta May 5.

The group established several daily hourly resolution proxies from the shells of sea clams of Tridacna species using a confocal laser scanning microscope (CLSM) and secondary ion mass spectroscopy at the nanometric scale (NanoSMIS).

Now they have applied these techniques to the Earth environment. They established a daily-weekly resolution of the land snail shell oxygen isotope (δ¹⁸Os), which could well reconstruct precipitation events on a meteorological scale in the study region.

Cathaica Fasciola snails are readily available in IECAS and are selected for ultra-high resolution (~30 microns) δ¹⁸Bone analysis.

Meanwhile, the amount of precipitation and its oxygen isotope compositions have been monitored on the IECAS campus since 2019. The researchers found that variations in the ultra-high resolution δ¹⁸The Os sequence resembles monitored changes in precipitation (i.e. amount and isotope of oxygen), and both oxygen isotope records showed a negative trend from April 2020 to September 2020.

Moreover, the six negative excursions in δ¹⁸Os matched well with six periods of increased precipitation in detail. And there was a strong correlation between precipitation oxygen isotope data and snail shell for all six events, suggesting the potential for quantitative reconstruction of precipitation amount using negative δ¹⁸Bone data.

This evidence demonstrates that terrestrial snail shells are valuable and promising ultra-high resolution archives for characterizing terrestrial paleoclimates, such as extreme precipitation events.

Widely distributed and well-preserved fossil snails in loess-paleosol sequences on the Chinese Loess Plateau show great potential in reconstructions of paleo extreme precipitation events.

So far, the research group has collected a large amount of fossils from various climatic contexts, and the related paleological studies are still ongoing.