In Practice, v. 7, no. 1, fall 2006

Indice Autores Presentación Capítulo 1. La trastienda de la Historia Regional Capítulo 2. Los estados provinciales. Una conceptualización provisoria Capítulo 3. Poder político y estrategias de reproducción en los territorios de Neuquén y Río Negro, Argentina (1983-2003) Capítulo 4. La dinámica articulación de redes sociales y políticas Capítulo 5. El estado-partido neuquino. Modos de legitimación y Políticas Sociales Capítulo 6. Asistencia Social y políticas alimentarias: tensión entre legitimación y control social Capítulo 7. El proceso de construcción de la ciudadanía. El caso del municipio de Cutral Co, Neuquén Capítulo 8. Neuquén como campo de protesta Capítulo 9. El movimiento estudiantil universitario del Comahue (1969-1976) Capítulo 10. Asociaciones empresarias federativas en Neuquén. Avances y retrocesos Capítulo 11. El modelo productivo de provincia y la política neuquin

New records and geographic distribution map of Bothropoides diporus Cope, 1862 (Reptilia: Viperidae)

We provide two new records of Bothropoides diporus for Neuquén province, northern Patagonia, Argentina. Both records are the second and third for this species in this province. One of these records, from the northern slope of Auca Mahuida Mountain, extends approximately 120 km to the north the present known geographic distribution of this species in Neuquén province.Fil: Minoli, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Janis Alvarez, Diego. Universidade Federal do Rio Grande do Sul; BrasilFil: Avila, Luciano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Integrated stratigraphy of the Upper Hauterivian to Lower Barremian Agua de la Mula Member of the Agrio Formation, Neuquén Basin, Argentina

The Upper Hauterivian to Lower Barremian Agua de la Mula Member of the Agrio Formation (Neuquén Basin, Argentina) was studied applying an integrated stratigraphic approach and facies analysis. The ammonite biostratigraphy of the member has been improved based on bed-by-bed collecting. The already defined biozones (S. riccardii, C. schlagintweiti, C. diamantensis and P.groeberi) were recognized, precisely related to the succession, and further refinement was proposed. Sequences of different order are built by stacked starvation/dilution (S/D) sequences, regarded here as sixth order sequences with only two components that can be unequivocally distinguished: the lower starvation hemisequence and the upper dilution hemisequence. Pro- and retrogradational stacking pattern of S/D sequences define supra-ordinate sequences. The sequence-stratigraphic analysis resulted in the subdivision of the member into four main depositional sequences (DSAM-1 to -4) and several subordinate sequences. Previously published sequence stratigraphic charts of the Neuquén Basin did not relate sedimentary sequences to biozones, and are hence not comparable to the scheme presented here and other charts. Our study shows a good agreement with the sequence-chronostratigraphic scheme of European basins, thus arguing in favour of a predominantly eustatic control on sequence development during the Late Hauterivian to Early Barremian. A latest Early Barremian age is proposed for the almost ammonite-barren upper part of the Agrio Formation, based on correlations of sequence boundaries.Fil: Archuby, Fernando. GeoZentrum Nordbayern; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Wilmsen, Markus. Museum für Mineralogie und Geologie; AlemaniaFil: Leanza, Hector Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentin

Environmental and climatic proxies for the Cañadón Asfalto and Neuquén basins (Patagonia, Argentina): review of middle to upper jurassic continental and near coastal sequences

In this review, we include several proxies (sedimentology, palynology, invertebrates) from the Cañadón Asfalto and Neuquén basins, to infer the environments and regional climatic context during the Middle to Late Jurassic of Patagonia. In central Patagonia, early in the Middle Jurassic, and associated with a magmatic arc, began the sedimentary fi lling of Jurassic continental sub-basins in the Cañadón Asfalto Basin. Lacustrine and fl uvio-deltaic sediments, bearing a continental Middle Jurassic palynobiota, correspond to the Las Chacritas Member, while the sediments and palynobiota from the Late Jurassic Puesto Almada Member (both in the Cañadón Asfalto Formation) indicate a palustrine wetland subenvironment immersed within an arid macroenvironment. Paleoinvertebrates (conchostracans and sponges) of this formation suggest wet-dry cycles in the water bodies they inhabited. The sedimentological information together with the continental and coastal palynomorph assemblages of the back arc Neuquén Basin, allowed distinguishing a complete regressive-transgressive sequence for the Middle Jurassic Lajas Formation. For the Upper Jurassic in this basin, the thick gypsum and anhydrite deposits of the evaporitic coastal Auquilco Formation correlate with extended deposits of eolian sandstones corresponding to the Botucatú paleodesert, and a saltmarsh environment is inferred from the palynofl ora. The palynologic associations from both basins indicate a regional warm climate with seasonal aridity. Climatic conditions would have been drier in the continental interior (Cañadón Asfalto Basin), with strongly seasonally distributed temperatures, and moister in the western coast of the continent (Neuquén Basin), during the marine transgressions.Na presente revisão foram incluídos vários proxies (sedimentologia, palinologia, invertebrados), das bacias de Cañadón Asfalto e Neuquén, para inferir o contexto climático regional e ambiental durante o Jurássico Médio e Superior da Patagônia. Na região central da Patagônia, no início do Jurássico Médio, e associado a um arco magmático, começou o preenchimento sedimentar de sub-bacias continentais jurássicas na bacia Cañadón Asfalto. Os sedimentos flúvio-deitaico e lacustres, tendo uma palinobiota continental do Jurássico Médio correspondente ao Membro Las Chacritas, enquanto os sedimentos e a palinobiota do Jurássico Superior do Membro Puesto Almada (ambos na Formação Cañadón Asfalto) indicam um subambiente palustre úmido imerso em um macroambiente árido. Os paleoinvertebrados (conchostráceos e esponjas) desta formação sugerem ciclos úmidos-secos nos corpos de água por eles habitados. A informação sedimentológica juntamente com as assembleias de palinomorfos continentais e costeiros do “back arc” da bacia Neuquén permitiu distinguir uma sequência completa regressiva-transgressiva para o Jurássico Médio da Formação Lajas. Para o Jurássico Superior, os depósitos de anidrita e gesso espessos da Formação Auquilco costeira evaporítica correlacionam-se com depósitos extensos de arenitos eólicos correspondentes ao paleodeserto Botucatu. Um ambiente “saltmarsh” é inferido a partir da palinoflora. As associações palinológicas de ambas as bacias indicam um clima regional quente com aridez sazonal. As condições climáticas teriam sido mais secas no interior continental (bacia Cañadón Asfalto), com temperaturas fortemente distribuídas de forma sazonal, e úmidas na costa ocidental do continente (bacia de Neuquén), durante as transgressões marinhas.Fil: Volkheimer, Wolfang. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Quattrocchio, Mirta Elena. Universidad Nacional del Sur. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cabaleri, Nora Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotopica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; ArgentinaFil: Narvaez, Paula Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Rosenfeld, U.. Westfälische Wilhelms-universität Münster; AlemaniaFil: Scafati, Laura Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Melendi, Daniel Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentin

Ofiuroideos del Cretácico Inferior de Patagonia: primer registro fósil articulado para el Mesozoico de América del Sur

The first articulated remains of ophiuroids for the Mesozoic of South America are described from the Lower Cretaceous of Neuquén Basin, Argentina. The taxonomic analysis allows the assignment of the material described herein to the extinct genus Ophiopetra. The specimens belong to a new species, but considering the poor preservation, a new name is not introduced, as it would be based on an incomplete diagnosis. Certain characteristics (e.g., the diameter of the disc, the width/height ratio of the vertebrae) suggest that these ophiuroids are paedomorphic specimens. In light of the latest classification of the Ophiuroidea, and new insights on the spine articulation microstructure of Ophiopetra lithographica presented herein, a transfer of Ophiopetra to the family Ophionereididae within the order Amphilepidida is proposed. This material expands the palaeogeographic record of this genus, since it represents the first remains of Ophiopetra described in the Southern Hemisphere. It is also the first Cretaceous record of the genus worldwide.Fil: Fernández, Diana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; ArgentinaFil: Giachetti, Luciana María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; ArgentinaFil: Stöhr, Sabine. Swedish Museum of Natural History; SueciaFil: Thuy, Ben. Natural History Museum Luxembourg; LuxemburgoFil: Perez, Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Comerio, Marcos. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Pazos, Pablo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Metriorhynchidae (Crocodylomorpha: Thalattosuchia) del jurásico superior–cretácico inferior de la Cuenca Neuquina (Argentina), con comentarios sobre los moldes naturales del encéfalo

Los Metriorhynchidae fueron los únicos Crocodylomorpha con un estilo de vida marino pelágico. Relacionado con este estilo de vida, su peculiar plan corporal permite diferenciarlos claramente de los demás Crocodylomorpha. El registro fósil de los metriorrínquidos titonienses–berriasienses de la Formación Vaca Muerta (Cuenca Neuquina, Argentina) es excepcional, tanto en términos cuantitativos como cualitativos. Su diversidad taxonómica está compuesta por cuatro taxones: Cricosaurus araucanensis, Cricosaurus lithographicus, Dakosaurus andiniensis y Purranisaurus potens. Este registro fósil también se caracteriza por la preservación tridimensional de los materiales y por la preservación de numerosos moldes naturales de las cavidades del cráneo. En este trabajo se presenta una descripción de los moldes naturales del encéfalo de Cricosaurus araucanensis junto con una síntesis de los avances en el conocimiento realizados, en los últimos años, sobre estos cuatro taxones argentinos. La calidad de la información que aporta los moldes naturales, sumado a la cantidad de moldes recuperados, hacen del registro patagónico una pieza clave para la exploración y reconstrucción de la anatomía blanda de estos crocodilomorfos, y para la comprensión de los cambios fisiológicos que acompañaron los cambios estructurales del esqueleto. La comprensión de estos cambios permitirá delimitar las innovaciones evolutivas claves que le permitieron a los metriorrínquidos la conquista, sin paralelo entre los arcosaurios, del medio pelágico.Metriorhynchidae was the only Crocodylomorpha with a pelagic marine lifestyle. Related to this lifestyle, its peculiar body plan al- lows clearly differentiate them from others Crocodylomorpha. The fossil record of metriorhynchids from Tithonian–Berriasian levels of the Vaca Muerta Formation (Neuquén Basin, Argentina) is outstanding, in terms of quantitative and qualitative record. Its taxonomical diversity is composed by four taxa: Cricosaurus araucanensis, Cricosaurus lithographicus, Dakosaurus andiniensis, and Purranisaurus potens. This fossil record is also characterized by the tridimensional preservation of the materials and by the preservation of numerous natural endocasts of the skull cavities. Here, I made a description of the natural endocasts of the brain of Cricosaurus araucanensis together with a synthesis of the advances in the knowledge of these four taxa that were performed during the last years. The information that provides the endocasts, to- gether with the quantity of endocasts, make of the Patagonian fossil record of metriorhynchids a key to the exploration and reconstruction of soft anatomy of these crocodylomorphs, and for the understanding of the physiological changes that accompanied the structural changes of the skeleton. Understanding these changes will allow defining the key innovations that allowed to the metriorhynchids conquer the pelagic environment, unparalleled among archosaurs.Fil: Herrera, Laura Yanina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Influence of pre-Andean history over Andean foreland deformation: structural styles in the Malargüe fold-and-thrust belt at 35ºS, Andes of Argentina

We present the first complete balanced cross-section of the Argentinean Andes at 35ºS. Based on an extensive field survey and limited sub-surface information, we constructed a structural model in which both the tectonic inversion of Mesozoic normal faults and the formation of Cenozoic Andean thrusts play a role in the deformation. We obtained a shortening of 26.2 km, equivalent to 22% of the initial length. This value is lower than previous estimates obtained from partial cross-sections using non-inversion structural models. Comparison of our results with a geophysical model of the crust indicates that: (i) crustal thickness was not constant across the orogen before Andean shortening, but a thick (~45 km) crustal block was interpreted? in the west as a remnant of a Late Paleozoic orogeny, and a thinner sector (~32 km) was located in the east as a result of Mesozoic stretching; and (ii) the structural model presented in this work is more consistent with the regional shortening and crustal thickness trends than models which do not take into account tectonic inversion.Fil: Mescua, Jose Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Giambiagi, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Tassara Oddo, Andres Humberto. Universidad de Concepción; ChileFil: Gimenez, Mario Ernesto. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Hybrid coastal edges in the Neuquén Basin (Allen Formation, Upper Cretaceous, Argentina)

The Allen Formation records the first Ingression Atlantic to the Neuquén Basin during the Late Cretaceous. The definition of lithofacies and facies associations interpretation for stratigraphic sections in Paso Córdoba and Salitral Moreno area, Río Negro, Argentina allowed to establish the depositional system that characterized this transgression in the northeastern edge of the Basin. In this paper we present sedimentological analysis of conglomeratic, sandstone, heterolithic and pelitic facies, which allowed the interpretation of tidal channels (CM), intertidal flats (PI), tidal flat influenced by storms (PT), subtidal flat (PS) and shoreface deposits (CP) parts of the depositional environment. These deposits represent a sedimentary records preserved example of hybrid systems, in which, the base of the sequence has greater tidal influence, while the upper portion is dominated by wave action. The paleocurrent data indicating a NNW-SSE direction to the shore and correlations and spatial distribution of facies associations propose paleogeographic and paleoenvironmental interpretations to Malargüe Group base. Then in this paper the relationship of this coastal environment presents with wind systems previously defined in this area for the Allen Formation.Fil: Armas, María Paula. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente.; ArgentinaFil: Sanchez, Maria Lidia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentin

Tracking sea bed topography in the Jurassic. The Lotena Group in the Sierra de la Vaca Muerta (Neuquén Basin, Argentina)

The Lotena Group is a clastic to evaporitic unit up to 650 m thick that accumulated during the Middle to Late Jurassic in the Neuquén Basin, western Argentina. Extensive field work carried out in the Sierra de la Vaca Muerta and Arroyo Covunco areas, including the measurement of seven detailed stratigraphic sections and geo- logical mapping allow the discrimination of six unconformity-bounded units or sequences. The first sequence is composed of red beds and evaporites belonging to the Tábanos Formation that unconformably overlies strata of the Lower to Middle Jurassic Cuyo Group. Sequences 2 to 5 are shallow marine and display a basal sandstone interval attributed to confined shelfal sandstone lobes. These grade vertically into unconfined shelfal sandstone lobes, and terminate with carbonate deposits. The basal interval is restricted to the thickest areas of each sequence, a relationship attributed to structural relief. Sequence 6 has a very irregular shape and strongly trun- cates the underlying deposits. It is composed almost entirely of massive carbonate strata that were deposited by density currents. Facies analysis and stratigraphic mapping suggest periodic recycling of previous accumula- tions. Stratigraphic evidence suggests that the Lotena Group in the Sierra de la Vaca Muerta and adjacent areas probably accumulated over a tectonically unstable basement. Sequences 1, 2 and 3 display evidence of accumu- lation in an extensional tectonic setting, while sequences 4, 5 and 6 experienced a northward shift of their depocentres associated with extensive erosional truncation of the marginal areas, suggesting that accumulation was affected by early stages of growth of the Covunco anticline.Fil: Zavala, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Impact of volcanism on the sedimentary record of the Neuquén rift basin, Argentina: towards a cause and effect model

The analysis of volcano-sedimentary infill in sedimentary basins constitutes a challenge for basin analysis and hydrocarbon exploration worldwide. In order to understand the contribution of volcanism to the sedimentary record in rift basins, we study the Jurassic effusive-explosive volcanic infill of an inverted extensional depocentre at the Neuquén Basin, Argentina. A cause and effect model that evaluates the relationship between volcanism and sedimentation was devised to develop a conceptual model for the tectono-stratigraphic evolution of this volcanic rift basin. We show how the variations in the volcanism, coupled with the activity of extensional faults, determined the types of volcanic edifices (i.e., composite volcanoes, graben-calderas, and lava fields). Volcanic edifices controlled the stacking patterns of the volcanic units as well as sedimentary systems. The landform of the volcanic edifices, as well as the styles and scales of the eruptions governed the sedimentary input to the basin, setting the main variables of the sedimentary systems, such as provenance, grain size, transport and deposition and geometry. As a result, the contrasting volcaniclastic input, from higher volcaniclastic input to lower volcaniclastic input, associated with different subsidence patterns, determined the high-resolution syn-rift infill patterns of the extensional depocentre. The cause and effect model presented in this study isolates the variables of the volcanic environments that control the sedimentary scenarios. We suggest that, by adjusting the first order input parameters of the model, these cause and effect scenarios could be adapted to similar rift basins, in order to establish predictive facies models with stratigraphic controls, and the impact of volcanism on their stratigraphic records.Fil: D'Elia, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Martí, Joan. Consejo Superior de Investigaciones Científicas. Instituto de Ciencias de la Tierra Jaume Almera; EspañaFil: Muravchik, Martin. University Of Bergen; Noruega. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bilmes, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología.; ArgentinaFil: Franzese, Juan Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentin