Early Jurassic intraplate extension in west-central Argentina constrained by U-Pb SHRIMP dating: Implications for the opening of the Neuquén basin

2020 ◽  
Vol 87 ◽  
pp. 278-302
Author(s):  
Lucas M. Fennell ◽  
Maximiliano Naipauer ◽  
Pablo Borghi ◽  
Lucía Sagripanti ◽  
Marcio Pimentel ◽  
...  
Keyword(s):  
Early Jurassic ◽  
Shrimp Dating ◽  
Central Argentina ◽  
West Central ◽  
Neuquen Basin ◽  
Neuquén Basin

First articulated stalked crinoids from the Mesozoic of South America: two new species from the Lower Cretaceous of the Neuquén Basin, west-central Argentina

2020 ◽  
Vol 94 (4) ◽  
pp. 716-733
Author(s):  
Darío G. Lazo ◽  
Graciela S. Bressan ◽  
Ernesto Schwarz ◽  
Gonzalo D. Veiga
Keyword(s):  
New Species ◽  
Lower Cretaceous ◽  
Carbonate Sediments ◽  
Exceptional Preservation ◽  
Central Argentina ◽  
West Central ◽  
Subaqueous Dunes ◽  
Neuquen Basin ◽  
Neuquén Basin ◽  
Slender Column

AbstractTwo new isocrinids are described from the Lower Cretaceous Agrio Formation of the Neuquén Basin, west-central Argentina. Isocrinus (Chladocrinus) covuncoensis new species is based on several beautifully preserved specimens from Valanginian beds of the Pilmatué Member. It is characterized by a small size, multiramose crown with six arm divisions, 240 arm tips, mostly isotomous branching, seven (or rarely eight) secundibrachials, smooth and stout column, short noditaxis, and pentalobate columnals. The species occurs in a 30 m thick interval of cross-bedded sandstones and mixed clastic-carbonate sediments that represent the migration of large, tidally influenced, subaqueous dunes developed in the offshore. Sudden burial of crinoids that dwelled on the dune toes and interdunes, possibly by the acceleration of the lee face migration, provided the exceptional preservation of specimens and thus this finding can be considered as a local crinoid Konservat Lagerstätte. Isocrinus (Chladocrinus) pehuenchensis new species is described from a single articulated specimen preserved in a silty calcareous concretion collected from a late Hauterivian concretion level of the Agua de la Mula Member. It is characterized by isotomous branching, eight or nine secundibrachials (IIBr), slender column ornamented with medial ridge of fine tubercles, interradius acuminated with fine tubercles on its tip, short noditaxis, and pentastellate columnals. It is associated with low-energy fall-out deposits in the offshore. The excellent state of preservation was due to an early cementation process by carbonate that enhanced lithification around the specimen.UUID: http://zoobank.org/4763ae70-9d0a-4015-b1c9-6a7ceeedfb1a

The gastropod family Aporrhaidae in the Lower Cretaceous of the Neuquén Basin, west-central Argentina

2014 ◽  
Vol 88 (6) ◽  
pp. 1222-1239 ◽  
Author(s):  
Cecilia S. Cataldo
Keyword(s):  
New Species ◽  
Lower Cretaceous ◽  
Single Species ◽  
Central Argentina ◽  
West Central ◽  
Neuquen Basin ◽  
Moderate Energy ◽  
Neuquén Basin ◽  
Water Carbonate

The gastropod fauna of the Lower Cretaceous of the Argentinian Neuquén Basin contains three aporrhaid species.Protohemichenopus neuquensisCamacho, 1953 is the most abundant, longest-lived, and most geographically widespread of the aporrhaids of this basin, and its protoconch and early teleoconch whorls were unknown until now. The new speciesDimorphosoma weaverifeatures convex to subtly angular spire whorls with opisthocyrt collabral ribs that are more prominent towards the mid-whorl, a bicarinate last whorl with small rounded nodes on the adapical carina, a simple, falcate labral wing which is more or less rectangular proximally and tapering and curving towards its distal end, and a short, straight rostrum.Tylostoma jaworskiiWeaver, 1931 is now placed inHarpagodes, and other previous, scattered, coeval records of this genus in the basin are now recognized as part of this single species. It is believed that whereasH. jaworskiipreferred shallower-water carbonate settings of low to moderate energy,P. neuquensisandD. weaverifavored siliciclastic to mixed clastic-carbonate environments, in deeper waters. In spite of its endemic elements, this aporrhaid association depicts a predominantly Tethyan influence.

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