YEARBOOK GEOLOGICAL SURVEY OF ESTONIA F. R. Kreutzwaldi 5 44314 Rakvere Telephone: (+372) 630 2333 E-mail:
[email protected] ISSN 2733-3337 © Eesti Geoloogiateenistus 2021 2 Foreword . 3 About GSE . 5 Cooperation . 6 Human resource development . 9 Fieldwork areas 2020 . 12 GEOLOGICAL MAPPING AND GEOLOGICAL DATA Coring – a major milestone in subsurface investigations in Estonia . 13 Coring projects for geological investigations at the GSE in 2020 . 15 Distribution, extraction, and exploitation of construction minerals in Pärnu county . 17 Mineral resources, geophysical anomalies, and Kärdla Crater in Hiiumaa . .22 Geological mapping in Pärnu County . .26 Opening year of the digital Geological Archive . .29 HYDROGEOLOGY AND ENVIRONMENTAL GEOLOGY Status of Estonian groundwater bodies in 2014–2019 . 31 Salinisation of groundwater in Ida-Viru County . .35 Groundwater survey of Kukruse waste rock heap . .37 The quality of groundwater and surface water in areas with a high proportion of agricultural land . .39 Transient 3D modelling of 18O concentrations with the MODFLOW-2005 and MT3DMS codes in a regional-scale aquifer system: an example from the Estonian Artesian Basin . .42 Radon research in insuffi ciently studied municipalities: Keila and Võru towns, Rõuge, Setomaa, Võru, and Ruhnu rural municipalities . .46 GroundEco – joint management of groundwater dependent ecosystems in transboundary Gauja–Koiva river basin . .50 MARINE GEOLOGY Coastal monitoring in 2019-2020 . .53 Geophysical surveys of fairways . .56 Environmental status of seabed sediments in the Baltic Sea . .58 The strait of Suur väin between the Estonian mainland and the Muhu Island overlies a complex bedrock valley . 60 Foreword 2020 has been an unusual year that none of us is likely to soon forget.