Vol 26, No 7 (2018)

The Kunzam La (Parahio) Formation along the Shian section of the Pin Valley was previously interpreted as containing Ediacaran–Cambrian boundary trace fossils, but re-examination of the Shian section shows that the oldest part of the section belongs to the late part of Cambrian Series 2, Stage 4, which contradicts the previous interpretation. The trace fossil assemblage comprises ?Arborichnus isp., Archaeonassa isp., Diplichnites isp., Hormosiroidea isp., Monomorphichnus lineatus, Bergaueria aff. langi, Palaeophycus tubularis, Rusophycus isp., and Treptichnus-like fossils that occur stratigraphically below the Oryctocephalus indicus biozone (Series 3, Stage 5) along the section and belong to the late part of Series 2, Stage 4. Sedimentary structures recorded along the section include hummocky cross-stratification (HCS) with deeply bioturbated tops, trough- and low-angle cross stratification, ball and pillow structures and climbing-ripple cross stratification. Integrated ichnofabric and sedimentological data suggest a storm-dominated, lower to upper shoreface shallow-marine environment of deposition.

The Middle–Late Permian reefs were formed in two paleogeographic realms: North Pangaea and Tethyan Realm. The basic reef builders in the first realm were representatives of Calcispongiae and Bryozoa; in the second realm, sphinctozoans, corals, and stromatoporoids. In these realms, various algae and cyanobacteria communities were of importance. Reef construction in the first realm associated with arid climatic conditions, isolation of water basins, and accumulation of salt-bearing sequences came to the end in the early Late Permian. Reef construction in the Tethyan Realm occurred in the Late Permian up to the Permian–Triassic boundary. The termination of reef construction was due to features of the reef ecosystem, which turned out to be unstable against the background of variations in the conditions and mass extinction at the Permian–Triassic boundary and dissociated before the termination of this extinction.

The calcareous nannofossils from the upper part of Garau Formation were studied in the NW Zagros Basin, western Iran (Kabir-Kuh section). The ca. 510 m thick studied interval is mainly composed of interlayered marls, marly limestones, marly shales, laminated black shales and limestones. The succession of nannofossil bioevents defines the stratigraphic range of the studied part of section spanning the interval from the early Barremian (CC5b/NC5C) to the late Aptian (CC7b/NC7B). Six primary calcareous nannofossil bioevents and eight secondary bioevents are recorded within the studied interval. The comparison of the recorded bioevents with those referred from other parts of the Tethyan and the Boreal realms indicates some diachroneity between these localities.

Planktonic and benthic foraminiferal assemblages from the upper Tortonian-lower Messinian part of the Gibliscemi section (Sicily, Italy), are described. The major stratigraphic markers recorded in the section are (1) the first occurrence of Globigerinoides extremus marking the lower boundary of the corresponding upper Tortonian zone, (2) first occurrence of Globorotalia miotumida that previously was considered as an index form of the Tortonian–Messinian boundary, and (3) the first regular occurrence of Globorotalia conomiozea recording this boundary. The distribution in the section of keeled Globorotalia and Globorotalia miotumida group is traced. The composition of the Globorotalia scitula group is analyzed and the group is proposed to be identified as one species G. praescitula. It is assumed that the Mediterranean in the Middle and Late Miocene was the site where Globigerinoides ruber survived during its complete disappearance in the Atlantic and Pacific.