The sedimentological and geochemical characteristics of sediments from Lake Szurpiły (northeastern Poland) can be used as a record of mass movement and climate dynamics since the Allerød. Late-glacial sediments suggest enhanced runoff conditions in the catchment after the retreat of the Scandinavian Ice Sheet, while Holocene varved sediments are interrupted by mass-movement deposits (MMDs). We identified 85 thin (<10 cm) MMDs (type 1) that consist of autochthonous material and frequently occur during the Atlantic period. Mobilization of littoral zone and slope sediments caused redeposition in the deepest part of the lake and was likely related to climatic conditions. In contrasting, one sedimentary unit (>1-m-thick MMD type 2) consists of auto- and allochthonous material and represents multistage processes, including erosion and deformation of underlying varved sediments, rapid deposition of clastic material, and redeposition of previously eroded varved sediments. Seismic activity or permafrost degradation was responsible for the deposition of MMD type 2. Furthermore, varve-thickness variability suggests Gleissberg and Suess solar cycles before 850 BC, when human impact was limited. Additionally, 22 and 11 yr sunspot cycles are recognized in light/dark laminae-thickness ratios and reflect influences of solar irradiance on lacustrine productivity.

We could identify three categories of solar proton events (SPE) with distinct solar origin from an analysis of direct and indirect observations during the years 1561-2016 CE spanning 42 sunspot cycles. They are (i) 10 MeV SPE whose number of occurrences closely follow the sunspot cycles (ii) 30 MeV SPE which show secular changes with peaks near Gleissberg solar cycle minima and inferred to be associated with distinct enhancements in the efficiency of the solar dynamo and (iii) those associated with Impulsive and irregular solar activity changes such as the Carrington event of September 1859. The relevance of above results for stars exhibiting cyclic and irregular activity changes will be also discussed.