Fluid Inclusion Study of the Neoproterozoic Nagthat Siliciclastic Sediments, NW Kumaun Lesser Himalaya: Implications to Quartz Cementation History

The fluid inclusion study in quartz overgrowth in the siliciclastics of Neoproterozoic Nagthat Formation reveals that the quartz cementation took place in the range of 80°C to 130°C with a salinity range of 0.82 to 9.18 wt. % NaCl. The microthermometric data, combined with petrographic and geologic evidences pennitted to constrain the nature of cementing fluids and source of cement. The silica for quartz cementation was derived partly from both the internal source (quartz and feldspar dissolution) and external source (pore fluids). It can be further suggested that the quartz cementation in the lower stratigraphic level (near the Chandpur Formation) is mainly by marine water while in the upper stratigraphic level (near the Blaini Formation), meteoric water has played an important role for the same.