Seafloor geological survey in Estonian shelf area

The first investigations of seafloor in Estonian shelf area are related to hydrographic surveying carried on in 18(th) c., when the Russian Hydrographic Survey launched composing the charts of the Estonian coastal sea. For the first time the scheduled systematic sampling of bottom deposits was carried out at end of the 191 c. and beginning of the 2011, c. After World War 11, the geological investigations on the seafloor had been launched in late 1960s - mostly aerogeophysical investigations carried in connection with oil and gas explorations. Systematic investigations directly related to the seafloor research were launched in 1973 when the Institute of Geology of the Estonian Academy of Sciences purchased RN Joldia. Medium-scale (1:200 000) integrated geological mapping of the Estonian shelf area supplemented with exploration works started in 1981, when the respective programme was compiled at the Geological Survey of Estonia and RN Marina as well as equipment needed for seafloor investigations were purchased. The investigation results are stored at the Depository of Manuscript Works whereas the reports of investigations and the metadata are kept in a digital database of the Euroseismic. New impetus in seafloor geological investigations came when in 1995 during large-scale geological mapping the hypothesis of presence of an impact structure in NW Estonia in the area of Neugrund bank was assumed and the impact origin of the structure was proven by marine geological investigations. Beside these many applied investigations and coastal monitoring were carried out in cooperation with several local and foreign partners.