Abstract A strongly depleted stable isotope composition, absence of 3 H and a low radiocarbon concentration are the main indicators of glacial origin of groundwater in the Cambrian–Vendian aquifer in northern Estonia. It is concluded from noble gas analyses that palaeorecharge occurred at temperatures c. 0°C. In some wells unexpectedly high gas concentrations have been found. Excess air, up to c. 50 %, is common but two-five times oversaturation is very unusual, requiting special processes and explanations, e.g. oversaturation may indicate recharge under high-pressure conditions, perhaps by subglacial meltwater recharge through the aquifers. Analyses of the gas composition in some groundwater samples also showed a rather high concentration of CH 4 , indicating the influence of biogenic reactions in the subsurface that could cause the rather negative δ 13 C values. Results of δ 13 C analyses in two CH 4 samples also show that the CH 4 is most likely of a biogenic origin. Based on the isotope data, the results of noble gas analyses, and considering the palaeoclimatic and palaeoenvironmental situation in Estonia during the late Weichselian time, it is concluded that palaeorecharge of Cambrian–Vendian aquifer most probably occurred during the last glaciation, probably by subglacial drainage through the tunnel valleys.

Abstract The development of Quaternary research in the Baltic countries was determined by geopolitical position as well as by economical and social conditions, the formation of science centres, the progress of geological thought, the natural environment and the specific geological development of this area of Eastern Europe. One of the peculiarities of Baltic Quaternary research was that it was undertaken initially by French, German, Russian, English, Finnish and Polish scholars, and later by Lithuanian, Latvian and Estonian researchers. The different nationalities infused Quaternary research with a variety of ideas and methods of study. Thus, within the course of investigations of both Quaternary and bedrock geology, specific periods related to progress in science and historical events in the Baltic States can be recognized: (1) scholastic period, drift hypothesis, Ice Age, glacialism, polyglacialism (Russian Empire administration until 1914); (2) geomorphological investigations (independent republics interwar years 1918–1939); (3) detailed investigations and mapping (Soviet administration 1940–1990); and (4) modern Quaternary studies (restoration of independence of Baltic States from 1990).