Field Trip Report - Society of Economic Geologists

Sweden field trip report:
SEG Student Chapter ETH Zürich
17 th -­‐26 th of June 2013
Stockholm, Sweden was the starting point for the trip around central and northern
Sweden joined by 8 members of the SEG Student Chapter Zürich.
Stops on the first day included outcrops and dumps of the historic Bästnas and Norberg
mining districts known for REE and Fe-­‐mineralisation in skarns.
On the second day NewBoliden hosted a visit to their Garpenberg “VMS” Zn-­‐Pb-­‐Ag
deposit. Johann Olsson and Michaela Aberg took us on tour along a drift, which showed
different kinds of mineralization including later Ag-­‐veinlets crosscutting earlier Zn-­‐ and
Pb-­‐mineralization in skarns. During the afternoon Åsa Erlfeldt and Giovanni Cibrario
were hosting a small discussion round on the larger scale deposits geology. Afterwards
they took us to the core-­‐shed to show us the different metavolcanic and
metasedimentary sequences and different mineralization types in core.
On June 18 th we stopped at outcrops and dumps of the Garpenberg area to see the
surface exposure of some skarn mineralization and volcanic sequences. In the late
morning we reached the Stollbergsgruva, a historic mine for Ag and Fe. In the afternoon
we made stops to visit the dumps of the Grängesberg Fe-­‐oxide-­‐Apatite deposit and old
workings of the Kopparberg/Finngruvan Cu workings.
After staying the night at Lake Alvlangen we visited BIF-­‐horizons on the lakeshore and
Accreted Lapilli in the surrounding area. Then we went on our way to the Persberg and
Langban mineral districts, which are famous for their mineral diversity and historic
mining for Fe-­‐skarns. Persberg is furthermore known as the birthplace of the term
skarn.
On June 21 st , we went to the Unesco cultural world heritage site at Falun. This historic
mine has been mined for Copper since the 10 th century. The rest of the day we used to
reach our destination of the day, lake Orsa.
On June 22 nd , we went on a long drive to the north. The destination was the Svartliden
deposit. The employees of Dragon mining invited us to their midsummer festivities in
the evening. On the following day Katerina Schloglova introduced us to the Svartliden
Au-­‐mine on the Gold-­‐line. She gave us a detailed overview of the different lithologies the
structural control of the deposit and gave us a tour around the open pit. After the visit
we set of towards Galliväre with a stop at a pegmatite near Jokkmokk with huge feldspar
and biotite crystals.
On June 24 th , Gregory Joslin and Sofia Höglund took us around the NewBoliden Aitik Au-­‐
Cu. The day started with an introduction into the deposit characteristics and mining
methods. In the pit they introduced us to the metavolcanic and metasedimentary host
lithologies that were subject to Amphibolite facies metamorphism. Furthermore, they

took us to outcrops of later pegmatite veins. The disseminated chalcopyrite and
chalcopyrite-­‐stringer mineralization was also pointed out. Afterwards we were taken
around the processing plant at Aitik with their autogenous mill and flotation plants.
After our visit we drove to our most northern stop of the trip at Kiruna. On June 25 th
Kari Niiranen gave us a tour around the largest underground Fe-­‐mine in the world
operated by LKAB. The day started with a presentation about the deposit its different
stratigraphies and mining methods. The underground visit gave an insight into
machinery used in large-­‐scale underground mines and the following tour of on of the
processing plants explained some of the difficulties and advantages of mining for
Kiruna-­‐type Magnetite-­‐Apatite ore. The day was rounded of with a visit to the core shed
where most significant stratigraphies could be investigated.
On the long drive back to Stockholm from Kiruna we made one final stop at outcrops of
the Alnö Carbonatite on the coast of the Baltic Sea, one of the prime examples for
Carbonatites in Europe.
We would like to thank everyone who has helped us with organizing this field trip. All
mentioned geologists in the visited mines and the associated companies as well as
several geologists familiar with the geology of Sweden who gave us precious tips on
which deposits and outcrops to visit and access to older field guides and further
literature (e.g. Erik Jonsson, Hannes Mattsson, Benni Mattsson and Torbjörn Bergmann).
Furthermore, we are grateful for the substantial funding from Data Metallogenica and
the SEG!

Sulfide mineralization in skarn with later veinlets rich in Ag at the Garpenberg mine

Metre-­‐scale biotite and feldspar crystals at a pegmatite near Jokkmokk

The Aitik Au-­‐Cu open-­‐pit mine

Participants of the field trip on the arctic circle