The Lavrion deposit (SE Attica, Greece): geology, mineralogy and minor elements chemistry

摘要

In southeastern Attica the Cycladic "Blueschist" and the "Basal" units are superposed and separated by a detachment fault. The widespread carbonate-hosted massive sulfide Pb-Zn-Ag ores of Lavrion are spatially related to the detachment fault, shear bands within marbles, and the shear contact between marbles and the intercalated metaclastics of the Basal Unit. The ores are both structurally and lithologically controlled. A low tonnage Ag-rich tension gash vein, hosted within hydrothermally altered hornfelses surrounding the Lavrion granodiorite, is structurally related to the regional stress field with roughly N-S direction. The ore mineral suite consists of base metal sulfides and a variety of sulfosalts and native elements. Galena and fahlore are the main silver carriers. There are no significant enrichments in minor elements other than Cd, Ag and Au. The sulfide mineral assemblages and the range of FeS compositions of sphalerite coexisting with pyrite, indicate an intermediate sulfidation state for the hydrothermal fluids generating the manto ores. Mineral assemblages characteristic of low or high sulfidation state are locally present. The ore geometry, structural and lithological control of the mineralization, textural features, carbonate alteration and si-licification, and the mineralogic and chemical composition of the ores suggest a carbonate-replacement deposit affiliation.