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Beryllium 10 concentrations ( 10 Be con ) were measured at annual resolution from varved sediment cores of Lakes Tiefer See (TSK) and Czechowskie (JC) for the period 1983–2009 (∼solar cycles 22 and 23). Calibrating the 10 Be con time-series against complementing proxy records from the same archive as well as local precipitation and neutron monitor data, reflecting solar forced changes in atmospheric radionuclide production, allowed (i) identifying the main depositional processes and (ii) evaluating the potential for solar activity reconstruction. 10 Be con in TSK and JC sediments are significantly correlated to varying neutron monitor counts (TSK: r = 0.5 , p = 0.05 , n = 16 ; JC: r = 0.46 , p = 0.03 , n = 22 ). However, the further correlations with changes in organic carbon contents in TSK as well as varying organic carbon and detrital matter contents in JC point to catchment specific biases in the 10 Be con time-series. In an attempt to correct for these biases multiple regression analysis was applied to extract an atmospheric 10 Be production signal ( 10 Be atmosphere ). To increase the signal to noise ratio a 10 Be composite record ( 10 Be composite ) was calculated from the TSK and JC 10 Be atmosphere time-series. 10 Be composite is significantly correlated to variations in the neutron monitor record ( r = 0.49 , p = 0.01 , n = 25 ) and matches the expected amplitude changes in 10 Be production between solar cycle minima and maxima. This calibration study on 10 Be from two sites indicates the large potential but also, partly site-specific, limitations of 10 Be in varved lake sediments for solar activity reconstruction. [ABSTRACT FROM AUTHOR]