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Orogenic gold deposits form in collisional or accretionary tectonic settings, and often in association with magmatic intrusions. As a result, the typical lithology has undergone extensive deformation and metamorphism. The deposits as such are largely controlled by structural geology and classified by the intervals of pressure and temperature at which they are emplaced. The Svartliden orogenic gold deposit studied here is shear zone hosted, located in the Bothnian Basin sediments intruded by the late‐orogenic Revsund granitoid during the Svecokarelian/Svecofennian orogen. The local geology mostly consists of metasediments and amphibolites.

The aim of this study is to determine the metamorphic conditions, the history of ductile deformation and the kinematics of the shear zone hosting the gold deposit. Mapping in the open pit mainly focused on the structural evolution and was complemented by microscopy and microprobe analysis.  

At least two phases of folding, F₁ and F₂, have been recognized. F₁ resulted in upright folds truncated by the main shear zone. F₂ occurs locally and displays subhorizontal hinge lines and shallow dipping axial surfaces. A late, overprinting crenulation lineation indicates a third phase of deformation.  

Kinematic indicators are represented by C/S‐fabrics, C’‐type shear bands and rotated lenses within the shear zone. These are visible both in the field and as microstructures found in thin sections. Altogether the observations point to an oblique‐slip, dextral north side‐up sense of shear, postdating F₁ and possibly coeval with the second generation. 

Thin sections from the quartz‐mylonite of the shear zone reveal recrystallisation mechanisms in quartz typical for two different temperature intervals. This indicates that a reactivation took place at a lower temperature locally. Sulphides located in C’‐orientations suggest remobilisation along shear surfaces. 

Microprobe analysis was conducted on a very local garnet‐amphibolite and shows that the garnet is almandine‐dominated in composition. Two types of amphiboles have been identified as hornblende and cummingtonite respectively, the latter most likely representing an alteration product replacing the hornblende. Geothermobarometry derived from the garnet amphibolite yields P‐T data of 3.9‐6.4 kbar and 554‐604°C, defining amphibolite facies conditions. Decreasing P‐T values from the core of the garnet towards the outer rim indicate uplift. A retrograde chemical zoning is visible representing a late equilibration, which also indicates uplift.