Leptite marker beds in quartz-banded iron ore, Gräsberg Mine, Central Sweden. The Gräsberg Mine is situated in the large Håksberg orefield. Two ore beds are exposed in the mine. They are torn apart by an intense shear-folding, with the ore bodies lying “en echelon”. Due to the occurrence of the two marker beds in the upper ore bed, it has been possible to determine the stratigraphic relations of the ore bodies. The marker beds also show that the ore beds are folded in a syncline with a fold axis dipping 45° to the NNE. This big fold is concealed by smaller, vertical shear-folds.