Regional similarities in lead isotopes and trace elements in galena of the Cyclades Mineral District, Greece with implications for the underlying basement

Highlights • Regional investigation of precious and base metal-rich deposits in the Cyclades • Pb-isotope and trace element analyses in galena by laser ablation ICP-MS • Galena inherits the Pb-isotopic signature of the underlying basement. • Distinct Pb-isotope signatures in the west and north-central Cyclades, Greece. • 206Pb/204Pb line follows the trace of known tectonostratigraphic units. Polymetallic ore deposits of the Aegean Sea, Greece, are temporally and spatially associated with the emplacement of Miocene granitoids and Pliocene to Quaternary volcanic units along the active volcanic arc and occur adjacent to the crustal-scale detachment systems. A variety of mineral deposits (e.g., carbonate-replacement, skarn, porphyry, vein-type, and low- to high-sulfidation epithermal deposits) formed during different stages of back-arc evolution and can be found in the footwall and hanging wall of the major detachment systems and all tectono-stratigraphic units. New galena Pb-isotope data collected by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis exhibit a range of isotopic ratios: 206Pb/204Pb: 18.68–18.91, 207Pb/204Pb: 15.67–15.75 and 208Pb/204Pb: 38.83–39.18, with a resolvable geographic pattern. Together with compiled Pb-isotope data of Cycladic galena, large-scale regional similarities in the Pb-isotope signatures are recognized, suggesting distinct sources of lead in the underlying basement. Base metal-rich deposits in the west Cyclades have a common lead source with a more radiogenic signature, whereas lead in the deposits in the north-central Cyclades was derived from a less radiogenic source. Similarities between the Pb-isotopic signature of galena and regional host rocks suggest, that the pre-Alpine Cycladic Basement was the main source of lead for the deposits in the north and central, and the metamorphosed volcano-sedimentary Lower Cycladic Blueschist Nappe was the source of lead for the deposits in the west. Moreover, there