| Summary: | A 650-yr-long sediment sequence from a crater lake on Tristan da Cunha, South Atlantic, was analysed for its 10 Be content. Based on 14 C dating, and sedimentary, geochemical, magnetic and palynological records, the period between 900 and 1450 AD appears to have been unusually stable in terms of sedimentation and vegetation and therefore this period was chosen for analysis of the 10 Be content. During this period of highly organic sedimentation and closed vegetation, the pattern of 10 Be flux variations follows the 10 Be fluctuations from the GRIP ice core and estimated 14 C production rates well. However, before and after this stable period, variable sedimentation rates have to be accounted for to obtain results that are comparable to the established 10 Be/ 14 C records. Our data show not only the possibility of obtaining detailed enough 10 Be flux data from sedimentary sequences to reconstruct past solar forcing but also how sensitive this type of record is to sedimentary and environmental changes. If suitable archives can be found, they have the potential to improve reconstructions of solar activity far back in time.
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