Selenium and Sulfur Systematics of Mafic Dykes in Western Fujian Province, Southern China

AbstractFifteen samples from three study areas (the Bancun diabase dykes, the Bali hornblende gabbro dykes, the Linzifen gabbro‐diabase dykes) were collected and analyzed for selenium (Se), sulfur (S), copper (Cu), major and trace elements. In general, Se, S and Cu do positively correlate to each other. The concentration of S and Se and the S/Se ratio are higher than the corresponding value of primitive mantle (PM), and the Cu/S ratio falls in a narrow range (0.04–0.29), which is consistent with that of primitive mantle (0.05–0.20). The Bancun diabase dykes and the Bali hornblende gabbro dykes were located in an intraplate environment during the Late Mesozoic. Oceanic subduction was closely related to magmatic activities. The magmatic activities play an important role in the transportation mechanism of Se and S. Because those two groups were closer to fault zones, which may affect the distribution of S and Se and other elements. In the two groups, no crustal contamination was observed, indicating that all analyzed elements may come from enriched mantle metasomtism associated with slab subduction. However, the Linzifen gabbro‐diabase dykes were located in an intraplate rift environment, and its invading age is older than the other two groups, the primitive magma comes from mantle, and there is an anomalous relation between S, Se and Al2O3, (La/Sm)N, and all these factors could result in higher S and Se concentration.