Lake and loess sediments represent archives that record important information about the local, regional and global climate conditions in the past. Lake sediments consist of autochthonous particles formed by biogeochemical processes within the lake and allochthonous particles brought into the lake from the catchment area. After deposition, the stratigraphy of the sediment can be altered by chemical, physical and biological processes. Under favored conditions, the sediment shows individual annual layers (varves), which can be used to date the sediment. Other dating methods are based on radioactive decay (14C, 210Pb) or on time markers such as tephra layers, deposits of natural catastrophes, e.g., floods, or radioactivity, e.g., emissions from a nuclear power plant.
Loess is a windblown deposit of fine dust originating from deserts and mountain areas. During the last 2.5 Ma, dust transported over several thousand kilometers formed plateaus up to 200 m thick. During warm and humid conditions, loess deposits are transformed by biochemical processes into soil. Until now, the main dating techniques applied to loess have been magnetostratigraphy (magnetic reversals), matching the 10Be concentration with the δ18O deep-sea record, radiocarbon (14C) dating (for the last 40 ka) and thermoluminescence (TL) dating (for the last 100-200 ka).