Contribution of the RSCM Geothermometry to Detect the Thermal Anomalies and Peak Temperatures Induced by Fluid Circulation in Metasediments

Abdeltif Lahfid (1) , Sylvain Delchini (1) , Brice Lacroix (2)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 Department of Earth and Environmental Sciences [Ann Arbor]

The occurrence of deposits hosted by carbonaceous materials-rich metasediments is widespread. For this reason, we propose in this study to investigate the potential of the Raman Spectroscopy of Carbonaceous Material (RSCM) geothermometry to detect thermal anomalies in hydrothermal ore deposits environment. The chosen geological context is the Lucia subterrane in the Franciscan Complex (California, USA), which includes gold-bearing quartz veins (Underwood et al., 1995). Estimated Raman temperatures 1) confirmed the increase in the metamorphic grade towards the north already shown by Underwood et al. (1995), using classical methods like mineralogy and vitrinite reflectance and 2) exhibit anomalous values. These anomalies are probably due to the later hydrothermal event. This result suggests that RSCM could be used as a reliable tool to determine thermal anomalies caused by hot fluid-flow.

Mots clés: Carbonaceous materials (CM); RSCM geothermometry; fluids circulation; hydrothermal over-print; peak temperatures and mineralization

Domaines: Planète et Univers [physics]; Sciences de la Terre; Planète et Univers [physics]; Sciences de la Terre; Géologie appliquée; Planète et Univers [physics]; Sciences de la Terre; Pétrographie; Planète et Univers [physics]; Sciences de la Terre; Minéralogie

Abdeltif Lahfid, Sylvain Delchini, Brice Lacroix. Contribution of the RSCM Geothermometry to Detect the Thermal Anomalies and Peak Temperatures Induced by Fluid Circulation in Metasediments. 13th SGA Biennial Meeting, Aug 2015, Nancy, France. 2015. ⟨hal-01164177⟩