The ammonite sequence in the Agrio Formation (Lower Cretaceous), Neuquén Basin, Argentina

1997 ◽  
Vol 134 (4) ◽  
pp. 449-458 ◽  
Author(s):  
MARIA B. AGUIRRE URRETA ◽  
PETER F. RAWSON
Keyword(s):  
Lower Cretaceous ◽  
Mediterranean Region ◽  
South American ◽  
The West ◽  
Lower Upper ◽  
Extensive Sequence ◽  
Major Revision ◽  
Upper Hauterivian ◽  
Neuquen Basin ◽  
Neuquén Basin

The Agrio Formation of the Neuquén Basin, Argentina, contains an extensive sequence of ammonite faunas, most of which are monogeneric. Detailed collecting through 15 sections across the basin has facilitated a major revision of the ammonite zonation. Formerly embracing four broad zones, the Agrio Formation is now divided into nine zones, the lowest four of which are divided into a total of 11 subzones. The new zonation provides a standard against which other South American faunas can be compared. The degree of subdivision now achieved is comparable to that for the ‘standard’ sequences of the West Mediterranean region. Although it is not possible to correlate the two regions in detail, the occurrence of some widely distributed genera (Olcostephanus, Karakaschiceras, Oosterella, Spitidiscus and Crioceratites) at well-defined levels in the Neuquén Basin provides some crucial links. Thus the approximate positions of the Lower/Upper Valanginian, Valanginian/Hauterivian and Lower/Upper Hauterivian boundaries can be determined.

scholarly journals Biostratigraphy and palaeoenvironment of the Agrio Formation (Lower Cretaceous), Mendoza Province, Neuquén Basin, Argentina.

2010 ◽  
Vol 33 (1) ◽  
pp. 47
Author(s):  
Sara Ballent ◽  
Andrea Concheyro ◽  
Guillermina Sagasti
Keyword(s):  
Surface Waters ◽  
Lower Cretaceous ◽  
Middle Part ◽  
Sea Bottom ◽  
Upper Hauterivian ◽  
Neuquen Basin ◽  
Storm Deposits ◽  
Neuquén Basin

 A bioestratigraphical and palaeoenvironmental study of the Agrio Formation, at the Cuesta del Chihuido section, southern Mendoza Province (35º45'S/69º34'W), Argentina, is presented. Thirty seven species of nannofossils, thirty four of foraminifers and six of ostracods have been recognized. Nannofossils association corresponding to Zones CC4A y CC4B indicates an Upper Valanginian-Upper Hauterivian age. At the base of the section, the presence of the benthonic foraminifer Epistomina loncochensis Ballent and radiolaria suggests eutrophic conditions of surface waters and oxygen depressed sea-bottom conditions. In the middle part of the section, diversity of lagenid foraminifers and nannofossils indicates a shelf and nearshore environment with clear and well-oxygenated waters. Abundant polymorphinids, spirillinids and involitinids towards the top of the section corroborate a general regressive tendency. Mudstones and silty-sandstone intercalations containing allochthonous adherent foraminifers and adult carapaces of cytheroid ostracods represent distal storm deposits.

First plesiosaur remains from the lower Cretaceous of the Neuquén Basin, Argentina

2003 ◽  
Vol 77 (4) ◽  
pp. 784-789 ◽  
Author(s):  
Dario G. Lazo ◽  
Marcela Cichowolski
Keyword(s):  
Lower Cretaceous ◽  
Sister Group ◽  
Monophyletic Group ◽  
Phylogenetic Position ◽  
Crown Group ◽  
Marine Reptiles ◽  
Stem Group ◽  
Neuquen Basin ◽  
Neuquén Basin

Plesiosaurs constitute a monophyletic group whose stratigraphical range is uppermost Triassic to uppermost Cretaceous (Brown, 1981). They were large predatory marine reptiles, highly adapted for submarine locomotion, with powerful paddle-like limbs and heavily reinforced limb girdles (Saint-Seine, 1955; Romer, 1966; Carroll, 1988; Benton, 1990). The Plesiosauria clade belongs to the Sauropterygia, which has recently been hypothesized as the sister-group of the Ichthyosauria. Together with that clade they form the Euryapsida (Caldwell, 1997). The Sauropterygia can be subdivided into relatively plesiomorphic stem-group taxa from the Triassic (Placodonts, Nothosauroids, and Pistosauroids), and the obligatorily marine crown-group Plesiosauria (Rieppel, 1999). Plesiosaurs are traditionally divided into two superfamilies: Plesiosauroidea, with usually small heads and long necks; and Pliosauroidea, with larger heads and shorter necks (Welles, 1943; Persson, 1963; Brown, 1981). Plesiosauroidea contains three families: Plesiosauridae, Cryptoclididae, and Elasmosauridae (Brown, 1981; Brown and Cruickshank, 1994). The validity of the Polycotylidae Cope, 1869, has long been questioned and its phylogenetic position among Plesiosauria debated, as many consider it to be related to the Pliosauridae or to be a sister-group of the Elasmosauridae (Sato and Storrs, 2000; O'Keefe, 2001).

Depositional and postdepositional processes of an oil-shale analog at the microstructure scale: The Lower Cretaceous Agrio Formation, Neuquén Basin, northern Patagonia

AAPG Bulletin ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 1679-1705
Author(s):  
Marcos Comerio ◽  
Diana E. Fernández ◽  
Nicolás Rendtorff ◽  
Mariano Cipollone ◽  
Patricia E. Zalba ◽  
...  
Keyword(s):  
Lower Cretaceous ◽  
Oil Shale ◽  
Northern Patagonia ◽  
Neuquen Basin ◽  
Neuquén Basin

Exceptional preservation of a barred shoreline under forced‐regressive conditions (Lower Cretaceous, Neuquén Basin, Argentina)

Sedimentology ◽  
2021 ◽  
Author(s):  
Manuel F. Isla ◽  
Mariana S. Olivo ◽  
Jerónimo J. Zuazo ◽  
Ernesto Schwarz ◽  
Gonzalo D. Veiga
Keyword(s):  
Lower Cretaceous ◽  
Exceptional Preservation ◽  
Neuquen Basin ◽  
Neuquén Basin

Lower Cretaceous (Berriasian-Aptian) biostratigraphy of the Neuquén Basin

2005 ◽  
Vol 252 (1) ◽  
pp. 57-81 ◽  
Author(s):  
M. Beatriz Aguirre-Urreta ◽  
Peter F. Rawson ◽  
G. Andrea Concheyro ◽  
Paul R. Bown ◽  
Eduardo G. Ottone
Keyword(s):  
Lower Cretaceous ◽  
Neuquen Basin ◽  
Neuquén Basin
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