Implication of Metamorphic Fluids on Cassiterite Precipitation in the Logrosan Sn-(W) Ore Deposit (Central Iberian Zone, Spain)

Fluid inclusions in the Logrosan ore deposits (Central Iberian Zone, Spain) host further constraints on the Sn-W ore deposits formation. Primary N-2-CH4-rich fluid inclusions found within cassiterite samples suggest that metamorphic fluids may have been involved in the Sn-bearing complex destabilization, and subsequent cassiterite precipitation. High N-2-CH4 concentration in mineralizing fluids indicates that assimilation of nearby organic-rich metasedimentary sequence host-rocks took place during the granite emplacement. In the studied case, mixing of metamorphic and post-magmatic fluids is likely to be responsible for the Sn-(W) ore deposit development and the cassiterite precipitation.