[1] The Nilosyrtis Mensae region is important among dichotomy boundary fretted terrain outcrops, as it provides evidence of overprinting of ancient landscapes by a suite of glacial features, providing a composite view of the variety of midlatitude glacial modification processes that can occur during recent Martian ice ages. On the basis of a series of criteria developed for the identification o...

Vertebrate paleontologists have proposed a model for the terrestrial end-Permian event in the Karoo Basin, South Africa. The scenario envisions vegetational collapse that resulted in a phased extinction of vertebrate taxa in the uppermost Daptocephalus Assemblage Zone and overlying Lystrosaurus Assemblage Zone. These biodiversity patterns are placed into composite stratigraphic sections at key ...

Palynological data from the Newark basin of the Newark Supergroup reveal a spike in the spore/pollen ratio at the TriasGc/Jurassic boundary. This spore spike is coincident with a 60% regional extinction of the palynoflora and approximately synchronous with terrestrial vertebrate extinctions. Orbitally controlled sedimentary cycles allow stratigraphic sections to be calibrated in time, constrain...

In a groundbreaking paper, Ward et al. (1) provided both the stratigraphic context and a quantitative description of the terrestrial vertebrate fossil record across the PermianTriassic (P-T) boundary from the Karoo basin in South Africa. They drew three primary conclusions: (i) that there was an accelerated gradual decline in diversity prior to the P-T boundary (in the Dicynodon Zone); (ii) tha...

[1] A kilometers‐thick sedimentary sequence in Gale Crater exhibits stratigraphic changes in lithology that are consistent with transitions in aqueous and climatic conditions purported to be global in scale. The sequence is divided into two formations, where the Lower formation exhibits a net transition in mineralogy from clay/sulfate to sulfate/oxide assemblages and is separated from the overl...

Forty eight years have elapsed since formal discussions were initiated, in 1948, on the position of the PlioPleistocene boundary. At the 18th International Geological Congress held in London during that year the Commission on the Plio-Pleistocene boundary recommended that “the Lower Pleistocene should include as its basal member the marine Calabrian Formation together with its terrestrial (cont...

Four volcanic-ash beds bracket the Early-Middle Triassic boundary, as defined by conodont biostratigraphy, in a stratigraphic section in south China. High-precision U-Pb dates of single zircons allow us to place the Early to Middle Triassic (Olenekian-Anisian) boundary at 247.2 Ma. Magnetic-reversal stratigraphy allows global correlation. The new dates constrain the Early Triassic interval char...

Literature reports upper Cretaceous to Middle Eocene flysch/wildflysch deposits from Mexico, Guatemala, Jamaica, Cuba, Puerto Rico, Barbados, Granada, Trinidad, Venezuela, Colombia, Ecuador and Peru. Early papers recording their widespread distribution and noting their tectonic implications are often overlooked by popular palaeogeographic and plate tectonic reconstructions of the Caribbean area...

frasnian - famennian boundary in the kal-e-sardar section (east of tabas, central iran) is investigated on the basis of conodonts. distribution of thirty-three species and subspecies in the stratigraphic column enables us to recognize a barren interval and five biozones; upper rhenana, upper part of upper rhenana - linguiformis, lower to middle triangularis, upper triangularis, lower crepida. b...

Stratigraphic subdivision of the New Zealand Pliocene-Pleistocene has its historical basis in biostratigraphy, especially in the shallow marine strata in the Wanganui and East Coast basins, North Island. Internationally, an astronomically calibrated, high resolution timescale is now well established for the PliocenePleistocene, based on predominantly precession-controlled sedimentary cycles in ...