Stratigraphy of the Neuquén Group, Upper Cretaceous of the Neuquén Basin (Argentina): new proposal for lithostratigraphic ordaining

Abstract

Stratigraphy of the Neuquén Group, Upper Cretaceous of the Neuquén Basin (Argentina): new proposal for lithostratigraphic ordaining. The Neuquén Group conform a succession of non-marine deposits of fluvial, aeolian and shallow lacustrine origin, developed in the Neuquén Basin between the Lower Cenomanian and the Middle Campanian (Upper Cretaceous). This succession reaches 1,200 m of maximum thick, being bounded at the base and the top by the Patagonidican and Huantraiquican unconformities respectively. In this paper two new formations are proposed (Los Bastos and Sierra Barrosa Formations, nom. nov.), and the subgroups were reconfigurated. Consequently, the Neuquén Group is composed lithostratigraphically by three subgroups and nine formations. The Río Limay Subgroup comprehend the Candeleros and Huincul Formations, representing low sinuosity channel deposits developed under tectonic and climatic subordinated control. The Río Neuquén Subgroup comprehend to the Cerro Lisandro, Portezuelo, Los Bastos, Sierra Barrosa and Plottier Formations, conforming a psamitic and pelitic interstratified succession of fluvial origin, mainly developed under climatic control. Finally, the Río Colorado Subgroup integrated by the Bajo de la Carpa and Anacleto Formations, comprehend fluvial deposits developed under a new dominant tectonic control. At the start of the deposition of the Neuquén Group, the Dorsal de Huincul worked as a structural high, generating toward the south of the Neuquén Basin one a small endorreic depocentre corresponding to the Picún Leufú Sub-basin, scheme that would have been keep up to ends of the deposit of the Candeleros Formation. During the rest of the deposit of this sequence, the drainage would have been kept without major modifications towards the pacific slope across a central collector flowing in sense N-NW. Towards the end of the deposit of the Neuquén Group takes place the inversion of the regional slope of the basin, making possible the ingression of the Atlantic Ocean and the beginning of the deposition of the Malargüe Group.Key words: Neuquén Group, new lithostratigraphic units, Upper Cretaceous, Neuquén Basin, Argentina.Resumen: El Grupo Neuquén conforma una sucesión de depósitos continentales de origen fluvial, eólico y lacustre somero, desarrollado en la Cuenca Neuquina entre el Cenomaniano Inferior y el Campaniano Medio (Cretácico Superior). Esta sucesión alcanza un espesor máximo de 1.200 m, encontrándose limitada en base y techo por las discordancias Patagonídica y Huantráiquica respectivamente. En este trabajo se proponen dos nuevas formaciones (Formación Los Bastos nom. nov. y Formación Sierra Barrosa, nom. nov.) y los subgrupos fueron reconfigurados. Consecuentemente, el Grupo Neuquén queda compuesto litoestratigráficamente por tres subgrupos y nueve formaciones. El Subgrupo Río Limay comprende a las Fms. Candeleros y Huincul, representando a depósitos de canales de baja sinuosidad desarrolladas bajo un control tectónico y climático subordinado. El Subgrupo Río Neuquén compre...

Cretaceous evolution of the Andean margin between 36°S and 40°S latitude through a multi‐proxy provenance analysis of Neuquén Basin strata (Argentina)

“…Although dinosaurs, charophytes, ostracodes, plant remains (Legarreta & Uliana, ) and palynomorphs (Vallati, , , ) are abundant in the continental sequences of Neuquén Basin, the precise ages of the different formations remain loosely constrained. According to published palaeontological and geochronological data (Bonaparte, ; Hugo & Leanza, ; Leanza et al ., ; Sánchez et al ., ; Garrido, ), in the present paper, we use the following ages (Figs and ): Aptian‐Albian p.p. for the Rayoso Formation (Bajada del Agrio Group); Albian for the Barda Colorada Formation; early Cenomanian for the Candeleros Formation (Neuquén Group); late Cenomanian‐Turonian for the Huincul Formation (Neuquén Group); middle‐late Turonian for the Cerro Lisandro Formation (Neuquén Group); late Turonian‐early Coniacian for the Portezuelo Formation (Neuquén Group); late Coniacian‐early Santonian for the Plottier Formation (Neuquén Group); Santonian for the Bajo de la Carpa Formation (Neuquén Group).…”

“…Based on published data (Sánchez et al ., ; Zavala et al ., ; Garrido, ) palaeocurrents are generally pointing to a North‐South longitudinal flow pattern in the basin, and thus do not provide detailed information on detrital provenance areas. For this reason we focus on other provenance proxies and only collected a few new palaeocurrent data, just to control the persistence of such a longitudinal distribution pattern during the studied interval.…”

A New Titanosaur (Dinosauria, Sauropoda) From the Upper Cretaceous (Cerro Lisandro Formation) of Mendoza Province, Argentina

“…The Cerro Lisandro Formation is widely exposed in Neuquén Province and is composed of fine clastic deposits, mainly monotonous banks of red mudstones interbedded with thin levels of fine, yellow and gray-green sandstones (Garrido, 2010). This facies association is interpreted to represent distal mud flats of fluvial systems (Leanza and Hugo, 2001).…”

“…Although their record is diverse, titanosaur remains are still unknown from some stratigraphic intervals in the Neuquén Basin. For example, until this paper, there was no record of well-preserved titanosaur fossils from the Cerro Lisandro Formation (middle-late Turonian; Garrido, 2010), and only fragmentary titanosaur bones and teeth were known from this unit (Salgado et al, 2009).…”

A new eilenodontine (Lepidosauria, Sphenodontidae) from the Lower Cretaceous of central Patagonia

“…In 1999, a field trip conducted by one of us (S.A.) under a project led by Fernando E. Novas (ANCP y T PID CT 01386) to outcrops of the Candeleros Formation (Neuqu én Group, Río Limay Subgroup), considered as Cenomanian-Turonian in age (Leanza et al, 2004;Garrido, 2010), resulted in the discovery of an outstanding locality, named 'La Buitrera,' that preserves articulated skeletons of small-to medium-sized tetrapods (Apesteguía and Novas, 2003;Apesteguía, 2008). The main components of this fauna are opisthodontian rhynchocephalians.…”