Tungsten and tin occurences in East Greenland

The East Greenland Caledonides host an array of tungsten (W) and tin (Sn) mineral occurrences, representing three different deposit types: skarn, greisen, and quartz-scheelite veins. Tungsten is found in scheelite and tin in cassiterite. The observed deposit types correspond to distinct geological processes driven by magmatic and metamorphic fluids during the Greenlandic Caledonides orogenic evolution. U-Pb dating, carried out at GEUS, of scheelite and cassiterite has led to the identification of three significant mineralisation pulses at ~425 Ma, ~400 Ma, and ~370 Ma. These correspond to the emplacement of S-type granites during thrusting, emplacement of A-type granites during the onset of syn-orogenic extension, and migration of metamorphic fluids released during late-orogenic extension, respectively. The first two pulses, related to magmatic fluids, formed skarn and greisen occurrences, and the latest event triggered the formation of quartz-scheelite veins. Trace element geochemistry on scheelite and cassiterite allows for the differentiation of the three studied deposit types. The geochemical fingerprinting provides a novel tool for identifying and differentiating cassiterite and scheelite deposit types, optimising early-stage exploration strategies in less-accessible terrain. Detailed analysis of mineral assemblages, geochemistry, U-Pb dating and structural controls have enhanced the understanding of the East Greenland mineral occurrences.