The Alta Vista Formation represents one of the first Late Cretaceous marine deposits accumulated during the foreland stage of the Austral Basin, Patagonia. All the analyzed samples contain dinoflagellate cysts denoting marine conditions throughout the unit and, despite the extremely poor preservation of the assemblages, diagnostic species were identified. The age of the Alta Vista Formation was assigned between the late Santonian and the late Campanian based on the invertebrate remains. Nevertheless, the age is still debatable and a detailed biostratigraphy has not been proposed for the unit so far. As in other Late Cretaceous Southern Hemisphere middle to high latitude successions, the dinoflagellate cysts from the Alta Vista Formation are useful for biostratigraphic interpretations. The co-occurrence of Odontochitina porifera, Palaeohystrichophora infusorioides, Nelsoniella aceras, Nelsoniella tuberculata and Xenikoon australis is consistent with a Campanian age, which in accordance with the age indicated by the invertebrates recorded in other localities in which the unit crops out. The occurrence of Xenikoon australis and Nelsoniella tuberculata constrains the age of the unit to the early—middle Campanian. Since the basal levels were not identified in the studied sections, the age herein suggested corresponds to the upper part of the Alta Vista Formation.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 54 • No. 6