Petrography, Diagenesis, Provenance and Tectonic Setting of the Sandstones of Upper Katrol Formation (kimmeridgian), Nakhtarana Area, Kachchh, Gujarat

The sandstones of the Upper Katrol Formation were studied with a view to understand the nature of Kachchh basin in relation to provenance and tectonic setting in the vicinity of Nakhtarana area. These Upper Katrol sandstones are fine to coarse grained, moderately to poorly sorted, sub-Angular to sub-Rounded and of moderate sphericity. These sandstones are composed of several varieties of quartz, feldspar, rock fragments, micas and a suite of heavy minerals derived from the Aravalli Range and Nagarparkar massif. Our study reveals that these sediments were derived from the continental block orogen provenance characterized by collision suture and fold thrust belts. Three types of cement encountered in this study include iron oxide, calcite and silica. Evidence of diagenetic modifications suggests an early stage of burial to a depth of 748 to 932 m for these sandstones. Porosity reduction is mainly due to early stage mechanical compaction and subsequent pervasive calcite and Fe-Calcite cementation, which was followed by the late stage authigenic kaolinization in the secondary pore space.