12:30 〜 14:00
[R7-P-11] FLUID INCLUSION STUDIES IN QUARTZ VEINS WITH TIN MINERALIZATION IN THE KIBARAN INTRUSIVE ROCKS IN KALEHE (SOUTH KIVU, DR CONGO)
「発表賞エントリー」
キーワード：Fluid inclusion, microthermotry, Kibaran mobile belt, Tin, Raman spectroscopy
The Mesoproterozoic Kibaran granitoid formations host numerous mineral resources which are highly demanded in new technology industries, mineral such as Sn-W, Nb, Ta and Au. This mobile belt is formed by collision of the Western Congo with the Eastern Tanzanian, Bangwelu and Zimbabwe cratons, producing four generations of granite. These ore deposits are hosted in granite pegmatite (Nb, Ta) and Sn-W in quartz veins.
Fluid inclusions were studied in quartz vein samples in order to unravel the evolution of the mineralizing fluid controlling the ore deposits in Kalehe(DR Congo). In the study area the field and petrographic studies indicate that major rocks constitute of a variety of metapelites including sericite schists, micas schists, quartzites and igneous rocks such as granites, greisens and pegmatites. The quartz veins crosscutting the metapelite show a NE-SW trending, whereas the pegmatitic vein trend in a NW-SE direction crosscutting the Kibaran metasediments.
Fluid inclusions are abundant in quartz veins and metallic mineralized quartz veins. Primary, secondary and pseudo secondary inclusion are observed, in which the biphase inclusions are most common.The mineralizing fluids of the quartz-vein in the sericite schist have a heterogeneous nature at the time of trapping. The temperature of homogenization(Th) and salinities of the fluid inclusions were determined; some were having high Th with high salinity, others were with high Th but with low salinity, whereas another group have low Th with moderate salinity. The biphase Inclusions homogenization temperature range is 17.7- 303°C and the salinity range is 0.88-16.24°Wt%. The temperature of first ice melting(Tmice)values obtained so far from fluid inclusion microthermometry indicate various fluid compositions mainly CO2, CO2 + H2O rich, CO2+H20+/-CH4. These phases were confirmed by Raman spectroscopy and consistent with Tmice as well as the freezing point depression indicating the presence of salt (NaCl or other salts).
The mineralizing fluids trapped as fluid inclusions in the metallic quartz veins crosscutting shale formations can also be categorized as primary, secondary and pseudo secondary, these fluids were multiphase fluid inclusion (solid, liquid and vapor). Detailed studies on these inclusions are being carried out and will be presented.
Fluid inclusions were studied in quartz vein samples in order to unravel the evolution of the mineralizing fluid controlling the ore deposits in Kalehe(DR Congo). In the study area the field and petrographic studies indicate that major rocks constitute of a variety of metapelites including sericite schists, micas schists, quartzites and igneous rocks such as granites, greisens and pegmatites. The quartz veins crosscutting the metapelite show a NE-SW trending, whereas the pegmatitic vein trend in a NW-SE direction crosscutting the Kibaran metasediments.
Fluid inclusions are abundant in quartz veins and metallic mineralized quartz veins. Primary, secondary and pseudo secondary inclusion are observed, in which the biphase inclusions are most common.The mineralizing fluids of the quartz-vein in the sericite schist have a heterogeneous nature at the time of trapping. The temperature of homogenization(Th) and salinities of the fluid inclusions were determined; some were having high Th with high salinity, others were with high Th but with low salinity, whereas another group have low Th with moderate salinity. The biphase Inclusions homogenization temperature range is 17.7- 303°C and the salinity range is 0.88-16.24°Wt%. The temperature of first ice melting(Tmice)values obtained so far from fluid inclusion microthermometry indicate various fluid compositions mainly CO2, CO2 + H2O rich, CO2+H20+/-CH4. These phases were confirmed by Raman spectroscopy and consistent with Tmice as well as the freezing point depression indicating the presence of salt (NaCl or other salts).
The mineralizing fluids trapped as fluid inclusions in the metallic quartz veins crosscutting shale formations can also be categorized as primary, secondary and pseudo secondary, these fluids were multiphase fluid inclusion (solid, liquid and vapor). Detailed studies on these inclusions are being carried out and will be presented.