Earth

Caves and climate in the past

A study of sediments transported within caves, their characteristics, their composition and their content in fossils allows the reconstruction of the variations of the environment on the surface and of the climate: in particular, remains of soil formed in tropical climates can be interesting, as well as sediments related to cold climates, such as material deriving from glacial or periglacial deposits. Speleothemes, on the other hand, are formed prevalently in warm climates and are therefore very important climate markers. In a way similar to that of ice cores, the isotopic analysis of the ratio 16O/18O enables us to determine air temperature when the calcite of which spleothemes are made of was deposited. The overlapping laminated structure and the possibility of dating calcite allow a reconstruction of the temperatures in the past that can be very detailed at times. The curve of past climatic fluctuations plotted with data from the analysis of cave speleothemes fits very well with paleo-climatic data obtained from other sources, such as the isotopic analysis of foraminifers (marine organisms with a calcareous shell) or pollen analysis.