Age of hydrothermal processes in the central iberian zone (Spain) according TO U-Pb dating of cassiterite and apatite
- 1 — Institute of Precambrian Geology and Geochronology of Russian Academy of Sciences
- 2 — Institute of Precambrian Geology and Geochronology of Russian Academy of Sciences
- 3 — Mineral Exploration Network Ltd.
Results of isotope-geochemical studies by PbLS step-leaching method of cassiterite from greisens located in Logrosán granite massif (Central Iberian Zone, Spain) and apatite from hydrothermal quartz-apatite vein on its exocontact indicate that in both cases a hydrothermal event is recorded in the interval of 114-126 Ma, which has been accompanied by lead supply. Within the limits of estimation error, the same age around 120 Ma corresponds to crystallization of hydrothermal apatite, formation of sticks and micro-inclusions in cassiterite from greisens and is suggested for Au-As-Sb-Pb ore mineralization, which calls for further confirmation. Xenogenous zircon from quartz-apatite vein does not react to this relatively low-temperature hydrothermal event either with building up new generations (sticks, areas of recrystallization) or with rebalancing of U-Pb isotope system. The age of greisen formation has been confirmed to be around 305 Ma by PbLS method on final phases of cassiterite leaching. Earlier it was estimated with 40 Ar/ 39 Ar method on muscovite.