Sedimentological characterization of Bara Formation sandstone, BhitNala Section Laki Range Southern Indus Basin, Pakistan

Abstract

Sedimentological characteristics of the Bara Formation sandstone which is exposed at BhitNala Section (BHNS), Laki Range,
Lower Indus Basin are studied based on textural and petrographic attributes in order to determine depositional environment,provenance
and tectonic setting. The Bara Formation of middle Paleocene is dominantly composed of sandstone along withsiltstone shale and
carbonaceous shale.Statistical parameters (kurtosis, skewness, sorting, median and mean) calculated through sieve analysis suggest that
the Bara Formation sandstone is medium to fine grained, moderately sorted, ranging in skewness from near symmetrical, positive to
negative with very Leptokurtic, Leptokurtic and Mesocratic kurtosis. Based on textural parameters and discriminatory diagrams Bara
Formation sediments deposited in fluvial to deltaic environment.The modal analysis data of 10 studied sandstone thin sections
dominantly plot on cratoninterior along with few points plot at recycled orogen. Hence, it is inferred that the source of Bara Formation
sediments isgranitic Indian craton occurring on the south east of study area with contribution from recycled detritus from post Bara
Formations. Besides, Bara Formation sandstone is classified as ferruginous quartz arenite and quartz wacke