REE geochemistry of auriferous quartz carbonate veins of Neoarchean Ajjanahalli gold deposit, Chitradurga schist belt, Dharwar Craton, India

REE composition of the carbonates of the auriferous quartz carbonate veins (QCVs) of the Neoarchean Ajjanahalli gold deposit, Chitradurga schist belt, Dharwar Craton, is characterized by U-shaped chondrite normalized REE patterns with both LREE and HREE enrichment and a distinct positive Eu anomaly. As positive Eu anomaly is associated with low oxygen fugacity, we propose that the auriferous fluids responsible for gold mineralization at Ajjanahalli could be from an oxygen depleted fluid. The observed positive Eu anomaly is interpreted to suggest the derivation of the auriferous fluids from a mantle reservoir. The location of Ajjanahalli gold deposit in a crustal scale shear zone is consistent with this interpretation.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► REE of carbonate veins and host BIFs of an orogenic gold deposit, India studied. ► These show U-shaped REE pattern with a positive Eu anomaly. ► Auriferous fluids are derived from a mantle reservoir of low ƒ(O2).