Foraminiferal Assemblage from Lockhart Limestone of the Lesser Himalaya, Abbottabad District, Northern Pakistan

Abstract

The Lockhart Limestone is well-established in different areas of division Hazara in the northern Pakistan. This study is an attempt to perform micropaleontological analysis of the Lockhart Limestone at the Changlagali section in district Abbottabad. The limestone at the study section is recorded to be 110 m thick, grey in color, medium-grained, hard, nodular and fossiliferous. It is thin to medium-bedded in the basal part, massive and brecciated to nodular in the middle part, and medium-bedded to massive and nodular in the upper part. It has been examined for foraminifers (planktic, smaller benthic and larger benthic) in order to outline foraminiferal biostratigraphy. A sum of 22 rock samples were collected from the Lockhart Limestone and thin sections were prepared for petrography. Subsequently, twenty-nine species, including five planktic, and eight smaller and sixteen larger benthic species, from fourteen genera were identified. Biostratigraphic zonations have been established on the basis of planktic foraminifers and integrated into standard planktic foraminiferal biozones. Biostratigraphically significant planktic foraminifers recorded were used to establish three biozones; Globorotalia angulata zone (Middle Paleocene age), Globorotalia pseudomenardii zone (late Paleocene age) and Morozovella velascoensis zone (Late Paleocene to Early Eocene age). Present micropaleontological analysis confirms that the Lockhart Limestone at the Changlagali section of Hazara area was deposited in the Middle to Late Paleocene age.