Paleogene stratigraphy of Kutch,India: an update about progress in foraminiferal biostratigraphy

The Paleogene sections of Kutch are the reference for the regional chronostratigraphic units of India. The ages of these dominantly shallow marine carbonates are mainly based on larger benthic foraminifera (LBF). The taxonomic revisions of the LBF and the progressively refined shallow benthic zonations (SBZ) have necessitated the present study on updating the stratigraphy of the area. The sedimentation in Kutch commenced with the deposition of volcaniclastics in terrestrial environments in the Paleocene. The marine transgression in SBZ 5/6 deposited finer clastics and carbonates, designated as Naredi Formation, in early Eocene. There is no evidence of marine Paleocene in Kutch. A major hiatus spanning SBZ 12 to SBZ 16 was followed by the development of a carbonate platform and deposition of Harudi Formation – Fulra Limestone during the Bartonian, SBZ 17. The hiatus corresponds to a widespread stratigraphic break in Pakistan and India to Australia, referred as the ‘Lutetian Gap.’ The Maniyara Fort Formation is assigned to SBZ 22 B and SBZ 23, and its age is revised to Chattian. Climate played a major role in building up of the Paleogene stratigraphic succession of Kutch, the carbonates formed during the warming intervals and the stratigraphic gaps were in the intervening cooling periods.     

Importance of active tectonics during karst formation. A Middle Eocene to Pleistocene example of the Lina Moutains (Irian Jaya,Indonesia)

Abstract

The Lina Moutains show a typical example of karst formation associated to recent and active tectonics. The limestone samples were collected from giant potholes present beneath the heavy rainforest, during speleological expeditions to the Bird’s Head of Irian-Jaya. Micropalaeontological data allow us to give a Middle Pleistocene age for the most recent karst formation. A detailed stratigraphy between the Upper Lutetian and the Middle Pleistocene was recorded, with tectonic events during the Oligocene and Pleistocene. The edge of the resurgence layer was also dated. We also conclude the probable existence of a subterraneous network downhill of the karst within the most recent levels of the Kais Limestone formation. We replace this formation within the tectonic evolution of this area between the Eocene and the Middle Pleistocene, in conjunction with the oblique convergence of the Pacific plate carrying volcanic arc fragments and the Australian margin, which resulted in folding, normal faulting associated with local extension, and wrench motion, which are settings capable of creating uplift of the carbonated platform. © Elsevier, Paris     

Failles normales Paléocène à Lutétien en zone sud-pyrénéenne (Aragon,Espagne) et flexuration de la plaque ibérique

Close to the South Pyrenean thrust front, synsedimentary normal faults develop in the ‘Garumnian’ continental deposits (Maastrichtian to Palaeocene) and in the carbonate platform during the Lutetian. During the Lutetian, this deformation is accompanied by a change in the sedimentation characterized by the deposit of two series of laminated limestones associated to monogenetic breccias. These normal faults would have formed at the bending of the Iberian plate subducting under Europe. They may also be considered as the starting point for the megaturbidites that deposited further north in the Eocene turbiditic basin. To cite this article: Y. Hervouët et al., C. R. Geoscience 337 (2005).     

A New Hiatus within the Lutetian of the El Basatin Section,Gebel Mokattam,Egypt:Field and Sedimentological Observations,with Special Emphasis on Nummulites

The Eocene succession of the El Basatin Section in Gebel Mokattam, east of Cairo, consists, from base to top, of two main units; the Mokattam and Maadi Formations. The Mokattam Formation consists of two Members, the Building Stone Member and the Giushi Member. The Upper Building Stone Member yielded six species of Nummulites belonging to the Upper Lutetian. These species are: Nummulites farisi Hussein et al., 2004; Nummulites cf. praegizehensis Boukhary and Hussein-Kamel, 1993; Nummulites cf. gizehensis(Forsk?l, 1775); Nummulites discorbinus(Schlotheim 1820) and Arxina schwageri(Silvestri, 1928) emended by Boukhary et al. 2012 and Nummulites crassichordatus Boukhary et al., 2010. The Giushi Member yielded three species that indicate a Bartonian age. These species, which continued from their first appearance in the Upper Building Stone Members, are N. discorbinus, A. schwageri and N. crassichordatus. The Maadi Formation, which has been previously considered to be of Bartonian–Priabonian age, is devoid of fossils in the study section. The two members of the Mokattam Formation represent a carbonate platform facies. The deposition of the Upper Building Stone Member was disturbed during the Lutetian by slumping and a convolute-bedding interval, indicating a short hiatus. The subsequent regression resulted in a very shallow marine to near-shore facies in the above Maadi Formation.