Recent biostratigraphic and sedimentologic studies in the lower–mid Campanian ammonite-rich shelf deposits of the James Ross Basin, Antarctica made possible a precise reconstruction of facies tracts along an onshore–offshore ...

Se describe una fauna de ammonites del Cretácico Superior, compuesta por especies de maoritas, gunnaritas, hypophylloceras y diplomoceras, y se discute su posición estratigráfica. También se incluyen especies encontradas ...

Status and correlation of Andean ammonite biozones are reviewed. Available calpionellid, nannofossil, and radiolarian data, as well as radioisotopic ages, are also considered, especially when directly related to ammonite ...

Ammonites are abundant and well preserved in the Tithonian-Valanginian (Upper Jurassic eLowerCretaceous) sedimentary successions of the central Chilean Andes, known as the Lo Valdes and Ba~nos delFlaco Formations. A total ...

Two ammonites from the Vaca Muerta Formation cropping out at the southern slope of Cerro Lotena (Neuquén Basin, Argentina) are described for the first time: 1) Simplisphinctes (Lotenia) neuquenensis, n. subgen., n. sp., ...

Although the Agrio Formation (Valanginian-Early Barremian) yields rich ammonite faunas at many levels, the highest beds are very sparsely fossiliferous. However, intensive collecting over the years has yielded a sparse ...

Arequipa basin has been studied by different authors, such as Jenks (1848), Wells (1953), Benavides (1962), Vargas (1970), Leon (1981) and Vicente (1981). These authors refer to the layers of the Chocolate Formation (Lower ...