Abstract An incoherent hydrothermally altered Cu- and Au-bearing shear zone has been discovered as a result of till geochemical exploration in the Petäjävaara site, northern Finland. Aerial photo interpretation, tractor excavations with sampling and analysis of earlier percussion drilling samples are the methods used in the study of Quaternary geology and till geochemistry. The bedrock in the Petäjävaara site is composed of quartzite, basic volcanic rocks and diabase dykes as part of the Peräpohja Schist Belt. Particular morainic landform types are ground, cover and Rogen moraines, of which the Rogen moraines take the form of a series of N–S ridges containing two separate till beds. A generalized model for the Au distribution in till at the Rogen moraine area is presented. Surficial parts of Rogen moraine ridges are the most significant for ore exploration. The local provenance of the material and high Au contents in the C horizon of the upper till bed are characteristic.