STRUCTURAL AND LITHOLOGICAL CONTROLS ON FLUID FLOW IN CARLIN-TYPE GOLD DEPOSITS IN NEVADA: INSIGHTS FROM STABLE ISOTOPES
Around the Betze-Post deposit, isotopic alteration is found up to 3 km from known mineralization, but is discontinuous laterally and vertically, with the most significant isotopic alteration coincident with both significant gold deposits and subvertical faults. At the Pipeline deposit, significant isotopic alteration occurs within the ore zone, but very little alteration is found beneath the deposits, inferring that fluids migrated laterally into the deposits. Around the Long Canyon deposit, isotopic alteration is largely restricted to damage zones immediately within and above the main zones of gold mineralization, and is consistent with the model put forward by Smith et al (2013) with hydrothermal fluid migrating laterally along boudin necks and fractures.
Together, the data highlight the complex nature of hydrothermal fluid pathways controlling Carlin-type gold deposits in Nevada, with several deposits appearing to be related to subhorizontal, rather than subvertical, hydrothermal fluid flow.
References: M.T. Smith, D. Rhys, K. Ross, C. Lee and J.N. Gray. 2013. Economic Geology v. 108 p. 1119-1145