Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

A. H. M. Ahmad ¹, G. M. Bhat ², Neshat Jehan ¹, A. F. Khan ¹, Aabiroo Majid ¹

Affiliations
1 Department of Geology, Aligarh Muslim University, Aligarh – 202 002, IN
2 Department of Geology, University of Jammu, J & K, IN

Abstract

The Habo Dome Sandstone of Chari Formation has been analyzed for petrofacies and diagenetic history. The sandstones are generally medium to coarse grained and moderately to well sorted. These sandstones are composed of several varieties of quartz, feldspar, rock fragments, micas and a suit of heavy minerals derived from the Aravalli Range and Nagarparkar massif. The petrofacies analysis reveals that these sandstones belong to the continental block, recycled orogen and rifted continental margin tectonic regime.

During mechanical compaction rearrangement of grains took place and point and long contacts were formed. The sandstones were cemented by calcite, iron oxide, silica, chalcedony and glauconite cements in order of abundance. Different graphs of porosity versus depth suggest a depth of burial in the range of 615 to 769m.

Keywords

Habo Dome, Chari Formation, Petrofacies, Diagenesis, Kachchh, Gujarat.

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A. H. M. Ahmad ¹, G. M. Bhat ², A. F. Khan ¹, C. Saikia ¹

Affiliations
1 Department of Geology, Aligarh Muslim University, Aligarh - 202 002, IN
2 PG Department of Geology, University of Jammu, Jammu - 180 006, IN

Abstract

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.

Keywords

Katrol Formation, Kimmeridgian, Sandstones, Petrography, Diagenesis, Tectonic Provenance, Nakhtarana, Gujarat.

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A. H. M. Ahmad ¹, A. F. Khan ¹, C. Saikia ¹

Affiliations
1 Department of Geology, AJigarh Muslim University, Aligarh-202002, IN

Abstract

The Middle Jurassic Athleta Sandstone of Jhurio Dome is mainly medium grained, moderately sorted to moderately well sorted, subarkose and is composed of four major lithofacies representing near shore tidal environments. Iron oxide, silica and glauconite cements mark the sandstones. Compaction is mainly mechanical and sandstones show good amount of porosity. Porosity reduction is mainly due to mechanical compaction in the early stage of diagenesis and subsequent pervasive iron oxide cementation.

Keywords

Depositional environment, Athleta Sandstone, Middle Jurassic, Jhurio Dome, Kachchh, Gujarat.

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