Constraints on age and origin of hydrothermal deposits in major crustal units of the Western Carpathians

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Hydrothermal ore mineralizations in the Low Tatra Mts. (Western Carpathians, Slovakia) comprise a variable group of parageneses, confined to ore veins in granitoid and high-grade metamorphic rocks. All these rocks are Variscan but they were strongly overprinted in the Alpine orogeny. The age and the origin of these mineralizations are unknown; because of the involvement of two orogenic cycles in this region, the history of the ore veins can be complex. Here, we propose a detailed study of the ore mineralizations in the Low Tatra Mts. The age of the mineralizations will be determined by U/Th-Pb dating on uraninite, monazite, and zircon, either by electron microprobe or by laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS). Using the latter technique, we will also analyze minerals which were not so far considered suitable for such dating, for example hydrothermal carbonates. Hence, we will exploit a major breakthrough in the analytical and dating possibilities and even attempt to date directly the primary sulfides. The dating of the minerals of the ore veins will be complemented by K/Ar dating of hydrothermal illite. Stable isotopes (C,S,O) analyses will be carried out together with fluid inclusion microthermometry in order to pinpoint the source of the ore components in the hydrothermal fluids. They will be coupled to the age determinations via considerations if the geochemistry of coeval fluids is controlled by the host rocks or if the disparate fluid chemistry reflects geotectonic events that occurred at different time in the Earth’s history. With the investigations done on two representative large deposits, we will attempt to place all data acquired here in a framework of tectonothermal evolution of the Western Carpathians and link the hydrothermal pulses to large-scale crustal events in this realm.