20: Varves as high-resolution archives of past climate and environmental change

Conveners Antti E.K. Ojala, Bernd Zolitschka, Arndt Schimmelmann, and Pierre Francus and Achim Brauer

Main convener e-mail antti.ojala at gtk.fi

Annually laminated (i.e. varved) sediments are known at multitudinous locations in diverse lacustrine and marine settings. Varves provide high-resolution sedimentary records with precise incremental time control, which can yield detailed time-series of biological, stable and radiogenic isotopic, geochemical and sedimentological parameters. Varve analysis can (i) yield climate reconstructions linked to topics such as hydroclimatic conditions, precipitation, and temperature, (ii) provide information on events like volcanic eruptions, earthquakes and flooding, and (iii) increase our understanding of anthropogenic impacts, such as soil erosion, pollution, and eutrophication on aquatic environments. Varves can document frequency and rates of change for environmentally relevant processes and enhance our understanding of sedimentary processes when applied together with sediment trapping and instrumental monitoring. This session appeals to a multidisciplinary audience of sedimentologists, paleolimnologists, and limnogeologists studying varves with high-temporal resolution at all timescales and from different environments. We welcome contributions related to climate, anthropogenic impacts on aquatic environments, and environmental monitoring. Moreover, we invite reports about developments in the interpretation of varves and improvements of geochronology, as well as new analytical techniques. This session is a contribution to the PAGES "Varve Working Group".