Abstract:
The Nammal Formation of Eocene age along the Salt Range Thrust (SRT) is
present in all the three sections of Salt Range. The main concern of this research is to
investigate the petrographic control on geomechanical characteristics of Nammal
Formation. The limestone of the Nammal Formation has been detailed studied under
the microscope. Strength and the mechanical tests are also applied. According to
Dunham’s scheme of classification, the petrographic study has suggested that the
limestone of Nammal Formation of Western Salt Range is bioclastic mudstone. At the
Sethi section of Central Salt Range, the limestone has been named as Bioclastic
wackestone. The limestone of the Nammal Formation of Eastern Salt Range is named
as the Bioclastic wacke-packestone. The observed diagenetic features include such as
neomorphism, dissolution and three types of carbonate cement. The geomechanical
results in which the strength tests (UCS, Brazilian and Schmidt Hammer test) and
aggregate tests (Loss Angeles abrasion, Water absorption, specific gravity and sulfate
soundness test) are indicating that this limestone can be considered for engineering
and construction. Micrite and sparry calcite cement helps in increasing strength values
while the presence of calcite veins, bioclasts and planktons may reduce the strength
values. The presence of marl portion in Nammal Formation is poor for the
engineering and construction.
