This summer five geologists from The Geological Survey of Estonia together with three students from the University of Tartu were given a chance to explore Kuusamo region in Finland, near the Arctic Circle – an area that features a unique blend of northern, southern, and eastern geology, relief, and nature.

They were welcomed by Oulu Mining School along with Geological Survey of Finland (GTK) in the Oulanka Research Station located in the Oulanka river valley within the Oulanka National Park. Purpose of this get-together was to learn from our northern neighbors and participate in a course “Geological and geochemical field techniques in mineral exploration.”

Although most days began with lectures, majority of the time in Kuusamo was spent in the field – on landscapes where the bedrock is buried under glacial sediments evident in the landscape as drumlins and eskers merged with bogs, lakes, and blueberry forests.

In the drumlin-covered area near Hangaslampi Estonian geologists got a chance to practice till sampling from about 1-meter-deep pits and weak leach sampling from the soil and plants to trace geochemical signals from the bedrock with some help from portable analyzers.

In the following days things got more interesting as our geologists had a chance to go boulder hunting, do some outcrop mapping and search for gold.

Boulder hunting took place in an area where GTK geologists had already identified a boulder fan with some Au mineralization. Gamma counter was used to identify mineralized boulders hidden under thick moss. However, sometimes just a hammer and a keen eye were used to search for “dirty” mineralized rocks.

Outcrop mapping took place at Juomasuo Co and Au deposit pit, where glacial sediments had been removed after the discovery of magnetic anomaly and possible mineralization. Mainly strike and dip angle of primary bedding and different structures were measured on the outcrop and later plotted on a geologic structure map. This task, however, proved to be quite a challenge for many, as the outcropped bedrock has very likely gone through several hydrothermal alteration events erasing the primary rock and replacing it with different mineralizations.

In the very same Juomasuo pit our geologists had a chance to extract heavy minerals from till samples that were collected previously from the drumlin-covered area near Hangaslampi. The extraction method was sieving and panning in water as only heavy minerals remained on the pan and rest of the sample was washed away.

The very last days of this intensive course were dedicated to noninvasive geophysical methods that can be used for mineral exploration and locating geological structures found deep below ground surface. Our geologists had the opportunity to carry heavy magnetometers on their backs through swampy bogs and drag georadar equipment uphill along an esker. Most geophysical fieldworks were done in the very same drumlin covered area near Hangaslampi to support geochemical findings from previous days.

A week spent in Kuusamo was certainly educational for our geologists. Yet, the real challenge now will be how to effectively apply these fresh perspectives into mineral exploration and geological studies in Estonia.