Abstract:
The Hazara-Azad Kashmir area lies in the northwest Himalayas of Pakistan. The Upper Cretaceous to Paleogene rocks are exposed in the fossiliferous sedimentary cover sequence of the Indian plate. The Upper Cretaceous-Paleogene rock sequence of the Kawagarh Formation, Hangu Formation, Lockhart Limestone, Patala Formation, Margala Hill Limestone, Chorgali Formation and Kuldana Formation has been investigated for micropalaeontological studies. In Hazara area, the Cenomanian to Campanian marine transgressive cycle deposited the micritic limestones of Kawagarh Formation on the north subducting shelf of the Neotethys Ocean below the Kohistan island arc. The presence of foraminiferal genera such as Globotruncana, Dicarinella, Rugoglobigerina, Hetrohelix, Planularia, Lenitculina, Globorotalites, Buliminella and Vaginulina in Kawagarh Formation Suggests that the formation deposited in shelf outer neritic conditions. This transgressive cycle ended before the Maastrichtian as a result the regressive to partially transgressive facies of Early Paleocene Hangu Formation deposited unconformably on the Kawagarh Formation. This regressive cycle occurred between the Maastrichtian to Lower Danian. This regressive gap is marked by the aerial, tropical and sub tropical brecciated quartzite, laterite and bauxite facies of the Lower Danian basal part of the Hangu Formation. However, the upper part of the Hangu Formation deposited partially transgressive restricted shallow marine to lagoonal facies as carbonaceous shale, coal seam, sandstone and siltstone in Upper Danian. The cretaceous-Tertiary Boundary on the basis of fossils can not be marked in Hazara and Azad Kashmir, as there is no record of Maastrichtian and Danian fauna. However, the K-T Boundary can be placed at the basal residual part of the Hangu Formation. The second transgressive cycle deposisted the Upper Paleocene-Early Eocene shallow marine limestone and shale sequence that includes the Lockhart Limestone, Patala Formation, Margala Hill Limestone and Chorgali Formation. The Middle Eocene Kuldana Formation records the transitional environments and marks the closing of the neotethys Ocean and initiation of Middle Eocene to Miocene continental molasses of the Muree Formation. In these study 23 sections were measured from Hazara and Azad Kashmir. More than 1000 outcrop samples were analyzed for microfossils and microfacies of the Upper Cretaceous to Paleogene sequence. The Paleogene of Hazara and Kashmir includes the genera of larger and smaller benthic foraminifers such as Lockhartia, Operculina, Miscellanea, Ranikothalia, Assilina, Nummulites, Alveolina, Clavulina, Quinqueloculina, Spiroloculina and Thalmannita. The microfacies and faunal analyses represent warm shallow marine inner shelf or inner neritic environments during paleogene transgression cycle. The Paleocene-Eocene Boundary is marked on the basis of disappearance of Lockhartia haimeis and Miscellanea miscella and the appearance of Nummulites atacicus and Nummulites mammillatus in the upper part of the Patala Formation and basal part of the Margala Hill Limestone.
Page(s):
69-87
DOI:
DOI not available
Published:
Journal: Geological Bulletin of the Punjab University, Volume: 40, Issue: 0, Year: 2005