Horsmanaho talc quarry, Finland

DESCRIPTION

GEOLOGY

Horsmanaho lies in the chromium rich area around Autokumpu, so it is common to find chromium minerals on the dump pile.
There is a very pure dolomite here, that is used as a reference in mineral analysis (I think).

VISITS

1997-06-26
We visited this mine on the way to Raippo (north of Ylämaa). It vasn't really on the way, north of Autokumpu, but it was really worth the trip. The dump pile was one of the biggest I've ever seen. Unfortunately I tripped on a loose rock when trying to see something interesting someone was showing. I fell flat on the ground, only stopping the fall with my fist around the hammerhandle. It hit so bad that it took four months to heal, and the outer joint of my long finger is slightly deformed.
It resulted in more exploring and not so much hammering on the rocks. It was very easy to find nice samples of serpentine with calcite and pyrite crystals. It was also very common with nice pieces of fuchsite and a dark schist with pyrite in thick layers. I saw one that found a piece approximately 30x20 cm, 2 cm thick that he was going make a cheese tray out of.

Mineral assemblage

Fuchsite, Magnesite (Breunnerite), Chlorite (ferroan chlinoclor), Antigorite, Chromite, Chrome-tremolite, Chrome-diopside, Pentlandite, Pyrrhotin, Chalcopyrite, dolomite, calcite, serpentine, pyrite, talc.

Dolomite
Dolomite in talc. This dolomite is a very pure and coarse crystalline. I think that they are using it as a norm when analysing other dolomite samples in Finland.
Collected 1997-06-26
(300 dpi, 800x600, k)

Fuchsite
Fuchsite schist with some sulphide (see below) and quartz.
Collected 1997-06-26
(300 dpi, 800x600, k)

Pyrite
Pyrite as yellow band in a black schist. This was a common sight on the dump pile. It came in all sizes and forms.
In the description of our trip, the black schist is described as a chalcopyrite banded chist, so I may have made a mistake in my analyse. I will make a chemical analyse real soon now.
Collected 1997-06-26
(300 dpi, 800x600, k)

Serpentinite
Serpentinite with pyrite and calcite on the surface.
Collected 1997-06-26
(200 dpi, 800x600, k)

Chromite
Small grains of dark chromite in a serpentinic rock.
Collected 1997-06-26
(300 dpi, 800x600, k)

If you have some questions, suggestions or comments you are welcome to write me a line or two.

Locality index. Main index.

axelsson@acc.umu.se

	Dolomite Dolomite in talc. This dolomite is a very pure and coarse crystalline. I think that they are using it as a norm when analysing other dolomite samples in Finland. Collected 1997-06-26 (300 dpi, 800x600, k)
	Fuchsite Fuchsite schist with some sulphide (see below) and quartz. Collected 1997-06-26 (300 dpi, 800x600, k)
	Pyrite Pyrite as yellow band in a black schist. This was a common sight on the dump pile. It came in all sizes and forms. In the description of our trip, the black schist is described as a chalcopyrite banded chist, so I may have made a mistake in my analyse. I will make a chemical analyse real soon now. Collected 1997-06-26 (300 dpi, 800x600, k)
	Serpentinite Serpentinite with pyrite and calcite on the surface. Collected 1997-06-26 (200 dpi, 800x600, k)
	Chromite Small grains of dark chromite in a serpentinic rock. Collected 1997-06-26 (300 dpi, 800x600, k)