No abstract

Land snails build their shells with carbon extracted pnncipally from their diet and are a good record of the vegetation and climate vanations through time. We have analyzed the carbon isotopic composition of shells of Vertigo modesta sampled in the Eustis Upper Pleistocene loess senes, Nebraska, which deposited between 18, 000 and 12, 000 years. A trend towards andity of the environment is observed from the base to the top of the sequence. Rhythmic and rapid oscillations, of about 1 000 years, of the carbon isotopic composition indicate more humid penods. These results are compared to other indépendant proxies from the same or nearby loess sequences. The validation of the land snails shells as new record of paleochmatic variations in loess sequences is thus demonstrated.