Indicator mineral analyses of stream-sediment samples using automated mineralogy and mineral chemistry: Applicability to exploration in covered terranes in eastern Alaska, USA

• DOI: 10.1016/j.oregeorev.2022.105021
• Publication Date: 2022-07-06T19:35:51Z
• Authors: Karen D. Kelley; Garth E. Graham; Katharina Pfaff; Heather A. Lowers; Alan E. Koenig
• Keywords: Bornite; Covellite; Chalcocite; Mineral exploration; Molybdenite; Sericite; Breccia; Marcasite

In the past two decades, significant research efforts have been devoted to porphyry copper indicator mineral (PCIM) identification and chemistry assist exploration. Such studies are important in Yukon-Tanana upland region of eastern Alaska because well-established geochemical exploration techniques, such as geochemistry stream-sediment samples, less effective search for resources owing cover materials that subdue signatures. The unglaciated is well-endowed with resources, including Cu-Mo-Au deposits at Taurus, Bluff, Dennison, Oreo. Using automated scanning electron microscope (SEM) numerous PCIMs identified rocks samples would likely not observed using visual binocular methods. Sulfide minerals chalcopyrite, chalcocite, covellite, bornite, molybdenite, pyrrhotite were rock more than half from drainages containing known occurrences contain chalcopyrite or without bornite. Many also these minerals, which suggests potential additional occurrences. Svanbergite, an aluminum phosphate sulfate (APS) [SrAl3(PO4)(SO4)(OH)6], was some altered mineralized stream may represent best Taurus-like deposits. Apatite has great a tool assessing presence mineralization. Grains high Cl (>∼0.4 wt%), Fe (>0.4 Mn (>2000 ppm) clearly distinguish apatite other sources (metamorphic, unmineralized igneous rocks). This study one first document new streamlined sample collection processing methods combine SEM techniques derived both bedrock surficial (stream) sediments they apply