Set against the backdrop of Finland’s rich Precambrian geology, the training offered an in-depth look at the bedrock of the Aijala-Orijärvi volcanic massive sulfide (VMS) mining district, where participants honed their skills in geological mapping and field observations. The week was a blend of fieldwork and theoretical lessons, beginning and concluding at the Geological Survey of Finland (GTK) office in Espoo. Instructors Ville Järvinen, Janne Hokka, and Jani Jäsberg guided participants through this multifaceted training, where they were introduced to the complexities of Precambrian bedrock and its deformations.

A Journey Through Time: Learning the Language of Rocks

Participants, including geologists from EGT (Sirle Liivamägi, Lennart Maala, and Johannes Vind) and BGS (Tara Stephens and Priyanka Paul), along with external trainee Georg Rahu from the University of Tartu, spent three days in the field, learning to identify various igneous, volcaniclastic, and sedimentary rocks in outcrops. The area’s rocks, formed within a tectonic arc system nearly 1.9 billion years ago, have been heavily altered and deformed over millennia. Thus, interpreting these rocks requires not only careful observation but also an understanding of how tectonic and metamorphic processes have shaped them.

The focus was on recognizing ore-fertile rock sequences, which might extend into Estonia’s own crystalline basement. Although in Estonia these rocks are primarily studied through drill cores, the ability to examine their counterparts in outcrops was invaluable. Participants were encouraged to connect field observations with geological interpretations, as the path to discovering ore lies in understanding the broader geological context, rather than relying on data or maps alone.

Modern Mapping: From Field to Database

One of the key components of the training was learning how to systematically document field observations and integrate them into digital geological maps. GTK’s workflow for mapping Precambrian bedrock was introduced, including the processes of data capture, quality control, and map creation in GIS. These skills are directly transferable to Estonia’s geological research, where similar rocks may exist but are more challenging to access and study.

Looking Forward: Expanding Expertise in Core Studies

The training highlighted the potential links between Finland’s Precambrian geology and the Estonian basement, encouraging participants to think critically about how observations made in outcrops could inform their understanding of Estonia’s subsurface geology. The EGT team hopes to participate in a follow-up training at GTK’s Loppi field base, where drill cores from the same region are archived. Working with drill cores will provide an additional layer of insight, enabling participants to expand their expertise in recognizing textures and correlating them with field observations.

A Grateful Collaboration

The workshop was a fruitful experience, combining theoretical knowledge with hands-on practice in a historically rich mining district. The instructors, Ville Järvinen, Janne Hokka, Jani Jäsberg, and geophysics expert Hanna Leväniemi, were highly appreciated for their expertise and guidance. The event not only deepened the participants’ understanding of Precambrian geology but also fostered collaboration between the EGT, BGS, and GTK teams, laying the groundwork for future research and exploration.