Soil geochemical data from the Nordkinn peninula, Finnmark

Abstract

The Nordkinn Peninsula consists of a series of Neoproterozoic fluvial, cross-bedded sandstones belonging to the Kalak Nappe complex wich are derived from basement terraines of the Fennoscandian shield (Roberts, 2007). On first glance the area appears to hold little promise for mineral exploration. However, numerous low density geochemical surveys (Nordkapp project - Bølviken et al., 1986, Kola project - Reimann et al., 1996, re-analysis of old Nordkalott samples - Reimann et al., 2011) show distinct geochemical anomalies (rare earth elements - REEs, U, and Th but also Pb, Bi, Zn, and Sb) on the Nordkinn and adjacent Varanger Peninsula. Because of the numerous unexplained anomalies it was decided to cover the Nordkinn Peninsula (ca. 2000 km2) with a local scale geochemical survey at a sample denisty of 1 site per 2 km2. During the summer of 2011 soil samples were collected from 808 locations at 1 km distance along ca. 30 traverses cutting the Nordkinn Peninsula in east-west direction with 2 km spacing between the traverses. Due to logistical reasons the Koifjord-\/Sandfjellet area could not be covered and parts of the Digermul Peninsula remained uncovered because Tana commune did not provide landing permits for the helicopter. All samples were air dried and sieved to pass a 2 mm nylon screen. Analyses for 65 elements, including REEs, were carries out by a commercial laboratory based on an aqua regia extraction and following tight quality control procedures. The regional distribution of most elements depicts geological boundaries. Maximum concentrations observed for the sum of the REEs exceed 2000 mg\/kg and the high REE values are clearly bound to one of the sandstone units. Several additional geochemical anomalies could be outlined.