DefinePK

Abstract

The Mughal Kot Formation is well exposed in the Mughal Kot, where a section of 1000m was studied particularly for its planktonic foraminifera. The studied section is dominantly comprised of nodular marls with minor intercalation of graded bedded lenticular sandstone and thick bedded limestone. The biostratigraphic investigations revealed abundant planktonic foraminiferal species of Globotruncana, Globotruncanita and Heterohelix. Based on these species, a single local planktonic foraminiferal biozone i.e. Globotruncana-Globotruncanita- Heterohelix Assemblage is erected. The biozonal information is integrated with previous literature and early to late Maastrichtian age (76 Ma to 69 Ma) is assigned to the Mughal Kot Formation. This study suggests that the overall species richness is low in the Mughal Kot Formation due to the high rate of sedimentation i.e. 142 mm/1000 years. This high rate of sedimentation is further supported by turbidite sequences at different stratigraphic levels within the Mughal Kot Formation. Such high rate of sedimentation causes a dilution effect in the basin, which subsequently resulted in the overall low species richness in Mughal Kot Formation. Furthermore, the overall species richness within the Formation indicates a decreasing trend from base to top of the section. This decreasing trend in the species richness suggest a shift from the cooler climate to warmer climate i.e. the shift in the nutrient structure resulted from more stratified ocean in the early Maastrichtian (76 Ma to 73 Ma) to mixed ocean in the late Maastrichtian (73 Ma to 69 Ma).