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 ...

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., ...

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 ...

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 ...

The Pseudofavrella angulatiformis Zone (upper Valanginian) of the Agrio Formation in the Neuquén Basin, Argentina, is characterized exclusively by a complex sequence of neocomitid faunas that are sandwiched between the ...

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 ...

The first magnetostratigraphic scales for the Jurassic through Early Cretaceous from the Southern Hemisphere have been constructed over the last decades from marine sections in the Neuquén Basin. Paleomagnetic sites were ...

Spitidiscus is a widely-distributed Hauterivian genus that briefly invaded the Neuquén Basin, Argentina, in mid Hauterivian times, well after it first evolved in the west Tethyan area. Its appearance in Argentina is linked ...