TY - THES

T1 - PbS-ZnS ore mineralization in SW-Sardinia, (Ingurtosu-Montevecchio), Fluid Inclusion Investigations

AU - Honisch, Maria

N1 - embargoed until null

PY - 2008

Y1 - 2008

N2 - In the course of this master thesis, samples were taken from selected led-zinc-deposits in SW-Sardinia in 2005 with the main focus on a gangue mineralization between the cities Montevecchio and Ingurtosu. In addition to their minaralparagenesis mainly the fluidchemistry of the samples was investigated. Therefore the following methods were applied: crush and leach, microscopy, Raman and microprobe. Supplementary a digital map of SW-Sardinia was created in ArcGis, where several parameters, e.g. ion-content in the fluids, are illustrated. The most important rock series of SW-Sardinia are the autochthon interpreted Nbida-, Gonnesa-, Cabitza- and Puddinga-formation. Those formations were folded during the Caledonian and the Variscan orogeny and were thrust faulted by ordovician-devonian series. Latter contain the Postgotlandiano-formation, which hosts the led-zinc-gangue deposits between Ingurtosu and Montevecchio. The crush and leach analyses of the quartz, calcite and barite show a significant evaporation trend that is approved by the anhydrite-crystalls within the quartz. The galena- and sphalerite-mineralization seams to derive from a second fluid event that shows no trend in the Na/Cl-Br/Cl diagram. The J/Cl-Br/Cl and J/Na-Br/Na diagrams show no significant change in the J/Br ratio. The paleotemperatures estimated with Na-K-thermometer vary around 300°C for PbS and almost all ZnS samples. With the aid of Ramanspectromentry different mineral phases have been distinguished and fluid inclusions in the transparent phases have been analysed. In addition a new method of the Raman-analysis for the estimation of the salinity was applied but the results are inexact. The method of microprobe was used to analyse the silver-content of the galena, which was about 0,02-0,06 wt% for the samples of Montevecchio and Ingurtosu and 0,00-0,02 wt% for the samples from the MVT and SEDEX deposits.

AB - In the course of this master thesis, samples were taken from selected led-zinc-deposits in SW-Sardinia in 2005 with the main focus on a gangue mineralization between the cities Montevecchio and Ingurtosu. In addition to their minaralparagenesis mainly the fluidchemistry of the samples was investigated. Therefore the following methods were applied: crush and leach, microscopy, Raman and microprobe. Supplementary a digital map of SW-Sardinia was created in ArcGis, where several parameters, e.g. ion-content in the fluids, are illustrated. The most important rock series of SW-Sardinia are the autochthon interpreted Nbida-, Gonnesa-, Cabitza- and Puddinga-formation. Those formations were folded during the Caledonian and the Variscan orogeny and were thrust faulted by ordovician-devonian series. Latter contain the Postgotlandiano-formation, which hosts the led-zinc-gangue deposits between Ingurtosu and Montevecchio. The crush and leach analyses of the quartz, calcite and barite show a significant evaporation trend that is approved by the anhydrite-crystalls within the quartz. The galena- and sphalerite-mineralization seams to derive from a second fluid event that shows no trend in the Na/Cl-Br/Cl diagram. The J/Cl-Br/Cl and J/Na-Br/Na diagrams show no significant change in the J/Br ratio. The paleotemperatures estimated with Na-K-thermometer vary around 300°C for PbS and almost all ZnS samples. With the aid of Ramanspectromentry different mineral phases have been distinguished and fluid inclusions in the transparent phases have been analysed. In addition a new method of the Raman-analysis for the estimation of the salinity was applied but the results are inexact. The method of microprobe was used to analyse the silver-content of the galena, which was about 0,02-0,06 wt% for the samples of Montevecchio and Ingurtosu and 0,00-0,02 wt% for the samples from the MVT and SEDEX deposits.

KW - fluid inclusions galena sphalerite Sardinia Montevecchio Ingurtosu ore mineralization crush and leach Raman microprobe

KW - Flüssigkeitseinschlüsse Bleiglanz Zinkblende Sardinien Montevecchio Ingurtosu Vererzungen Crush and Leach Raman Mikrosonde

M3 - Master's Thesis

ER -