Jouni Lerssi

Geological Survey of Finland | GTK · IT and GIS-Services

A combination of thermal infrared (TIR) images captured by uncrewed aircraft systems (UASs) and manual geophysical measurements with a GEM-2 device were used to better plan a water sampling campaign at an abandoned Au-Cu mine and an active Ni-Cu-PGE mine in the sub-arctic boreal zone in northern Finland. Anomalies from the TIR images and GEM-2 cond...

Geologiska forskningscentralen har som den första i världen landsomfattande kartlagt förekomsten av svartskiffer. Eftersom största delen av bergen i Finland är täckta av den jordmån som bildats under och efter de senaste nedisningarna låg främst berggrundens elektriska och magnetiska egenskaper som grund för kartläggningen. De geofysiska och geolog...

Geologian tutkimuskeskus on kartoittanut mustaliuskeiden esiintymisen maanlaajuisesti ensimmäisenä maailmassa. Kartoitus perustui erityisesti geofysikaalisiin tutkimuksiin, koska suurin osa Suomen kallioista on viimeisten jäätiköitymisten aikana ja niiden jälkeen muodostuneen maaperän peitossa. Geofysikaalisia tutkimuksia täydennettiin valitsemalla...

Geological Survey of Finland has mapped the distribution of black shales in Finland using airborne geophysics and geological, petrophysical and geochemical studies [1] (Fig. 1). Black shales contain over 0.5% of organic C and have in most cases deposited on seafloor in anoxic conditions. Black shale is a heterogeneous rock type: rock assemblage, mi...

The Summanen structure is located in Central Finland and is one of Finland's 12 known meteorite impact structures. In 2017, the discovery of Summanen was based on numerous shatter cone boulders with planar deformation features (PDFs) and a circular electromagnetic anomaly, which is 2.6 km in diameter. The site was revisited in 2020 and 2022, and sh...

Risk management of the environmental impacts of black shales in Finland Black shales are sedimentary rocks containing > 0.5% of organic carbon. Organic matter and S-rich compounds primarily deposited on seafloor together with silt- and clay-size detritus. Sulphide mineralogy, rock assemblage, textures and chemical characteristics vary from one bla...

Black shales host critical raw materials such as graphite and cobalt and occur in the vicinity of many types of sulphide deposits. We report the procedure for country-wide mapping of graphite- and sulphide-rich rocks and the chemical and petrophysical data of 319 samples we selected from sulphide occurrences and mines in Finland. Even though black...

We present the final results of the country-wide black shale mapping of Finland. Black shales host, e.g., sulphide and graphite deposits. They occur in the vicinity of other types of sulphide deposits as well and their chemical composition may be used as a pathfinder in exploration. The black shale database is important for regional and environment...

Geologian tutkimuskeskus kartoittaa mustaliuskeiden esiintymistä Suomessa. Kartoitus perustuu kallioperän sähköisiin ja magneettisiin ominaisuuksiin sekä syväkairausten ja kalliopaljastumien geologiseen tutkimukseen. Mustaliusketietokanta ja sen käyttöopas julkistetaan syksyllä 2022. Tietokanta on ollut koekäytössä useiden vuosien ajan. Mustaliuske...

This two-part paper reports results of data integration using different machine learning methods for target-scale prospectivity modeling of gold mineralization. The study area is the Rajapalot project area in the Northern Fennoscandian Shield in Finland. In this Part 1 paper, prospectivity modeling was implemented using knowledge-driven- and hybrid...

Black shales host polymetallic sulphide deposits and, moreover, they occur in the vicinity of other types of sulphide deposits and may serve as key horizons in exploration. Black shales are rarely outcropped in glaciated or deeply weathered terrains but can be traced with geophysical surveys. We have recently completed the mapping of Precambrian bl...

This guidebook collects the methodologies and experiences GTK has received in bedrock groundwater studies in mining areas in the past few years. It does not cover all the aspects or methods of mining hydrogeology, but provides an outlook of macro scale studies performed in Finland. For a hydrogeology expert the guidebook is a checklist of common me...

The Summanen structure (62°39.00N, 25°22.50E) is located within the Paleoproterozoic Central Finland Granite Belt, Fennoscandian Shield. The structure is hidden under Lake Summanen and not directly observable. It owes its discovery to low-altitude airborne geophysical data, which revealed a circular, ~2.6 km wide electromagnetic in-phase, and resis...

Many of the secondary raw materials (SRM) in landfills constitute valuable and scarce natural resources. It has already been recognised that the recovery of these elements is critical for the sustainability of a number of industries and SRM recovery from anthropogenic waste deposits represents a significant opportunity. In this study, the character...

Because of the need for modern lightweight electromagnetic sensor for near surface mapping in Geological Survey of Finland (GTK) in the beginning of year 2015 GTK purchased GEM-2 multi-frequency broadband electromagnetic sensor. During the year 2015 sensor was field-tested in several geologically and environmentally different targets and purposes....

Although mining companies have long been conscious of water related risks, they still face environmental management challenges. Several recent environmental incidents in Finnish mines have raised questions regarding mine site environmental and water management practices. This has increased public awareness of mining threats to the environment and r...

The mineral systems concept is intended to extend and inform exploration capability, through understanding processes of metal extraction, transport and precipitation within a well-defined architectural framework, as opposed to simple – or even sophisticated – targeting of geophysical or geochemical anomalies. Given that geophysical and geochemical...

Airborne geophysical surveys cover the whole of Finland and offer high-resolution magnetic, radiometric and electromagnetic datasets for various geo-scientific applications. This short ‘user guide’ provides background methodology, or ‘tips and tools’, to improve the extraction of geological information from the multivariate airborne geophysical dat...

Extended abstract, pages 468-471. ISBN 978-91-7403-207-9

Extended abstract in: Proceedings of the 12th Biennial SGA Meeting, 12–15 August 2013, Uppsala, Sweden, ISBN 978-91-7403-207-9, p. 600-603. (Keynote presentation)

Electrical resistivity tomography (ERT) and transient electromagnetic (TEM) surveys were done in Luikonlahti tailings impoundment area, Eastern Finland. Purpose of the measurements were to find the structure of the tailings impoundment area and possible seepage areas. Totally 5 ERT profiles and 4 TEM profiles were measured in the tailings area. ERT...

T alvivaara on tällä hetkellä yksi Suomen suurimmista kaivoksista, mutta se on myös maailman suurin mustaliuske-malmi, ainakin tonnimäärältään. Tal-vivaaran mineraalivarannot ovat Talvivaaran kaivososakeyhtiön viime vuonna julkaiseman arvion mukaan 1550 Mt. Eri metallien keski-pitoisuudet ovat 0,22 % nikkeliä, 0,13 % ku-paria, 0,02 % kobolttia ja 0...

Turvetutkimusten menetelmäkehitystarkastelu aloitettiin Keski-Suomen harvapistekartoitus–projektin yhteydessä keväällä 2009. Projektissa todettiin tarve kehittää GTK:n käyttöön turvetutkimusmenetelmiä ja työkaluja, joilla tutkittavat suot saataisiin kartoitettua entistä kattavammin ja kustannus-tehokkaammin turvetutkimusten kokonaislaadun heikkenem...

The goals of the HIRE (High Resolution Reflection Seismics for Ore Exploration 2007-2010) project have been to (1) extend reflection surveys to exploration of the Precambrian crystalline bedrock of Finland, (2) apply 3D visualization and modelling techniques in data interpretation, and (3) improve the structural database on the most important miner...

An increasingly urgent challenge in mineral system analysis is to extract relevant information from diverse datasets, and to effectively discriminate between "hydrothermal noise" and alteration and structures that may relate to significant mineralization potential. The interpretation of geophysical data is notorious for the problem of ambiguity in...

Lake Junttiselkä, located in central Finland, has been loaded by effluents from Pyhäsalmi Zn–Cu mine since 1962 and also receives Pyhäsalmi municipal effluent. A total of 32 top sediment samples (0–2, 2–4, and 4–6cm) were collected in October 2005 and March 2006 to examine the seasonal variation in sediment composition. Furthermore, two sediment co...

Weights-of-Evidence (WofE) and Radial Basis Function Link Net (RBFLN) were applied to soil group mapping in eastern Finland. The data consisted of low altitude airborne geophysical measurements, Landsat 5 TM-satellite image, and digital elevation model (DEM) and slope information derived from it. Probability maps were constructed for each soil grou...

The purpose of this study was to find out the influence of black schists to metal and sulphur content of peat. Geophysical ground measurements, logging and peat sampling were done over the chosen profiles in selected peatlands. Element concentrations of peat samples were analysed in laboratory. Exact positions of black schists were mapped using air...

Geological Survey of Finland (GSF) has contributed considerably to the rapid expansion of the Finnish peat industry and simultaneous helped to implement the National Mire Conservation Programme. In order to process this growing demand of information GSF has enhanced their procedures with modern data / information processing techniques. To support t...

The transformation of airborne electromagnetic (AEM) data into apparent resisitivity and depth is traditionally made separately for each measurement point and does not take into account the neighbouring data or model values or multiple frequencies. Laterally constrained inversion, where the model roughness is minimized together with the data error...

The use of airborne geophysical data for environmental studies started in GTK already in the 1970s, but came into common use only in the late 1990s. In recent years airborne data have been used successfully especially in environmental studies related to old mines and old mining districts, groundwater and soil contamination. This paper presents five...

Geological Survey of Finland has mapped surficial Quatemary deposits mainly at a scale 1:20000. These large scale maps cover only part of Finland. To fulfil the needs of the customers and the authorities a new mapping program begin in 2003 to produce maps and database at scale 1:250 000, covering whole Finland by the year 2007. The new database wil...

In: Carlson, L., Kuula-Väisänen, P. and Loukola-Ruskeeniemi, K. (Eds.) Ympäristö, terveys ja turvallisuus kaivannaisteollisuudessa. (The applications of nation-wide black shale database in the environmental issues of the mining industry)

Printed Map 1 : 1 000 000 and a database. A nation-wide map covering whole of Finland. Please see the description of contents in the article attached. ISBN: 951-690-762-8

Extended abstract in: Lehtonen, T. (toim.) Sovelletun geofysiikan XII neuvottelupäivät, Joensuu 10-11.11.1999. Laajat tiivistelmät. Vuorimiesyhdistys-Bergsmannaföreningen r.y., Sarja B, No 72, 2 sivua. (extended abstract, 2 pages)

Sulfide-rich black shales have environmental impacts, in some cases even hazardous ones, especially if the bedrock is broken and exposed and the rocks are in contact with surface waters. Release of harmful elements such as arsenic from sulfide-rich black shales have, for example, caused fish kills (Pasava et al., 1995). In the natural environment,...

The Global Geoscience Transect SVEKA (GGT/SVEKA), a 160 km wide, 840 km long strip in the central part of the Fennoscandian shield, covers the western part of the Archean Karelian Province in the northeast, crosses the boundary zone between the Karelian Province and the Paleoproterozoic Svecofennian arc complex, traverses the main tectonic units of...

Geological Survey of Finland (GSF) has carried out systematic airborne geophysical surveys in Finland since 1951. The second program started in 1972 using a flight altitude of 30-40 meters and line spacing of 200( 100) meters (Lohva et al, 1996; Peltoniemi, 1986). Today 80 % of the country has been measured. The measurements have been made with fix...

Geological Survey of Finland (GSF) has carried out systematic airborne geophysical surveys in Finland since 1951. The second program started in 1972 using a flight altitude of 30-40 meters and line spacing of 200(100) meters (Kurimo, et al, 1986; Peltoniemi, 1982; Poikonen, 1991; Vironmaki, et al, 1982). Today 80 % of the country has been measured....

The PGE mineralized zones referred to as the Ala-Penikka PGE Reefs (AP I and AP II) are located about 250 m and 340 m above the base of megacyclic unit IV in the Penikat layered intrusion, both mineralizations being hosted by plagioclase-augitebronzite and narrow poikilitic plagioclase cumulates. A depression structure (pothole) about 300 m long an...