1,720,974 research outputs found
Tectonic inversion in the Santa Barbara System of the central Andean foreland thrust belt, northwestern Argentina
Get PDFThe Santa Barbara System (SBS) of northern Argentina is a 400 km long segment of the Subandean foreland thrust belt. It is characterized by predominantly west verging, relatively high-angle thrust faults. Many of these faults are reactivated normal faults from one branch of a complex Cretaceous to Paleogene rift system. Heteroaxial folding in parts of the SBS is probably due to a slight component of range-parallel dextral strike-slip motion acting on preexisting faults striking north and NE during inversion. Regional balanced cross sections along two transects across the northern SBS indicate that the major faults flatten into a detachment in the basement at about 10 km depth. Neogene E-W contraction in the SBS is of the order of 21-26 km. Rift extension is not very well constrained but was probably less than 10 km. The structural style of the SBS differs from the thin-skinned Subandean thrust belt to the north and from the large-wavelength Sierras Pampeanas basement uplifts to the south. The changes between the different styles are sharp and coincide with the northern and southern boundaries of the rift in the foreland, suggesting that crustal or lithospheric heterogeneities exert an overriding control on foreland structural style.Fil: Kley, Jonas. Universität Karlsruhe. Institut Geologisches; AlemaniaFil: Monaldi, Cesar Ruben. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentin
New records of Tremadocian conodonts (Early Ordovician) from the Zenta Range, Jujuy Province, Argentina
Get PDFTHE study area is located nearby the Santa Ana village, province of Jujuy, in the Zenta Range of the Cordillera Oriental, northwestern Argentina. Localities can be reached by the national Route 9 to the town of Humahuaca, then continue to the East through the provincial Route 73 up to the Santa Ana village (Fig. 1). In this contribution we analyze an Ordovician conodont fauna from 15 levels of calcarenites and coquinas, along with graptolites, trilobites and associated fauna from siltstones and claystones. The studied collection of 2263 conodont elements is housed in the Museum of Paleontology at the National University of Córdoba, under repository code CORDMP 21941 to 22023.Fil: Zeballo, Fernando Javier. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; ArgentinaFil: Albanesi, Guillermo Luis. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Voldman, Gustavo Gabriel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Monaldi, Cesar Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta; Argentin
Age correlations for the acoite formation (lower ordovician) at Aguas Blancas Creek in the Cordillera Oriental of Jujuy province, Argentina
No full textHere, we use conodont and graptolite assemblages to age correlate the ‘Sepulturas limestones’ facies of the Acoite Formation exposed at Aguas Blancas Creek, near Altos de Lip an in the Cordillera Oriental of Jujuy Province, Argentina. An association of autochthonous conodont species is identified consisting of Drepanodus arcuatus, Drepanoistodus pitjanti, Erraticodon patu, Gothodus andinus, Paroistodus parallelus and Zentagnathus argentinensis. Tubaria referable to the graptolite genera Acrograptus, Baltograptus and Tetragraptus are also present. This assemblage corresponds to the middle interval of the Gothodus andinus Zone, together with the upper Tetragraptus azkharensis Zone, or possibly the lower Baltograptus cf. B. deflexus Zone, which collectively indicate an early to middle Floian (Early Ordovician) age. Lithological and faunal characteristics of the studied succession imply deposition in a shallow marine environment. We also suggest that the Aguas Blancas section is stratigraphically younger than the other upper outcrops exposed around the town of La Cienaga, where the ‘Sepulturas limestones’ were originally defined.Fil: Albanesi, Guillermo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Rueda Roballo, Ehimar Kristal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Ortega, Gladys del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Monaldi, Cesar Ruben. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Preserved extensional structures in an inverted Cretaceous rift basin, northwestern Argentina: Outcrop examples and implications for fault reactivation
Get PDFDuring the Cretaceous-Eocene interval a system of intracontinental rift basins, the Salta group rift, evolved in northwestern Argentina. Individual segments of the rift later suffered different degrees of inversion during Cenozoic shortening. The Tres Cruces subbasin, on the west side of the Eastern Cordillera, was strongly deformed, being now part of a thick-skinned thrust belt with a predominantly N-S structural trend. On its eastern border, tilting due to folding and thrusting and subsequent erosion have produced exceptional outcrops of preserved east-trending extensional structures including half grabens, rollover anticlines, and extensional fault-propagation folds. Farther west, the synrift succession is only intermittently exposed, although the interference of north- and east-trending structures as well as peculiar, dome-shaped anticlines with spur-like extensions suggest that north-and east-trending Cretaceous faults were reactivated, particularly near their intersections. Compilation of published data and analysis of our new data focused on the Salta rift indicates three main factors favoring the contractional reactivation of normal faults: dip angles lower than approximately 60°, especially for faults striking roughly normal to contraction; strikes no closer to the contraction direction than approximately 30°; and low downdip fault curvatures. Occasional dip-slip reactivation of east-trending faults does not match the present and long-term Andean stress regimes and presents an unresolved problem.Fil: Monaldi, Cesar Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta; ArgentinaFil: Salfity, Jose Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta; ArgentinaFil: Kley, Jonas. Universitat Jena; Alemani
Conodonts and graptolites of the Santa Rosita Formation (Tremadocian) at the Nazareno area, Santa Victoria Range, Cordillera Oriental de Salta, Argentina
No full textThe Nazareno area is located to the southeast of the Santa Victoria range in the Cordillera Oriental of Salta, Argentina, with extensive exposures of Ordovician rocks (Ortega and Albanesi, 2002; Brussa et al., 2003; Astini, 2003; Albanesi et al., 2008, and references therein). At this area a thick siliciclastic succession of the Santa Rosita Formation from the Lower Ordovician crops out (Turner, 1960) (Fig. 1). Previous works describe a succession that consists of sandstones and shales, and subordinate calcareous rocks with abundant fossils of early Tremadocian age (e.g., trilobites, braquiopods, gastropods, conodonts, acritarchs) (Harrington and Leanza, 1957; Vilela, 1961; Manca et al., 1995). The Paltodus deltifer conodont Zone of the upper middle Tremadocian was first identified in this area by Manca et al. (1995), who reported the presence of Paltodus deltifer Lindström, Drepanodus arcuatus Pander, Acodus deltatus deltatus (Lindström), among other taxa, however, the illustrations of these specimens do not allow a definite determination...Fil: Giuliano, María Eugenia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Albanesi, Guillermo Luis. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Ortega, Gladys del Carmen. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba; ArgentinaFil: Zeballo, Fernando Javier. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; ArgentinaFil: Monaldi, Cesar Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta; Argentina. Universidad Nacional de Salta; Argentin
Upper Cambrian/Lower Ordovician conodont and graptolite records in the Lari section, Salar del Rincón, Puna of Salta, Argentina
Get PDFLARI Creek, also named El Médano Creek, nearby the Salar del Rincón, is located in westernmost Salta Province, northwestern Argentina. It belongs to the Puna geological province, in the southern part of the Central Andean Basin (Moya et al., 1993). In this area, a succession of continental and marine Paleozoic rocks crop out. The lower sequence that bears significant index fossils is intruded by Ordovician volcanic rocks, and covered by clastic and pyroclastic deposits of Cenozoic age (Koukharsky, 1988; Moya et al., 1993; Koukharsky et al., 1996; Galli et al., 2010). This stratigraphic interval is particularly interesting because the index fossils reveal the transitional levels between the Cambrian and Ordovician systems and, therefore, the discussed position of the inter-systemic boundary in South America (Albanesi et al., 2010)...Fil: Giuliano, María Eugenia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Ortega, Gladys del Carmen. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba; ArgentinaFil: Albanesi, Guillermo Luis. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Ciencias de la Tierra; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba; ArgentinaFil: Monaldi, Cesar Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta; Argentin
Seismic and field evidence for selective inversion of Cretaceous normal faults, Salta rift, northwest Argentina
Get PDFNorthwestern Argentina was the site of the continental Salta rift in Cretaceous to Paleogene time. The Salta rift had a complex geometry with several subbasins of different trends and subsidence patterns surrounding a central high. Fault trends in the rift were extremely variable. There is evidence of normal and/or transfer faults trending N, NE, E and SE. It is not clear if all these faults were active at the same time, indicating a poorly defined extension direction, or if they formed in different, non-coaxial extension phases. In either case, their trends were very likely influenced by preexisting fault systems. Beginning in early Eocene time, the rift basins were superseded by Andean foreland basins and later became caught in the Andean thrust deformation propagating eastward, resulting in the inversion of rift faults. Due to their different orientations, not all faults were equally prone to reactivation as thrusts. N to NNE trending faults were apparently most strongly inverted, probably often to a degree where the traces of their normal fault origin have become obliterated. We present seismic evidence of moderately inverted N trending faults in the Tres Cruces basin and field examples of preserved E trending normal faults. However, reactivation sometimes also affects faults trending approximately parallel to the main Neogene shortening direction, indicating short-term deviations from the general pattern of Neogene thrust deformation. These pulses of orogen-parallel contraction may be linked to the intermittent activity of oblique transfer zones.Fil: Kley, Jonas. Universitat Jena; AlemaniaFil: Rossello, Eduardo Antonio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Monaldi, Cesar Ruben. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Habighorst, Bjórn. Universität Karlsruhe; Alemani
Geology and metal ore deposits in the Argentine Puna
No full textThis paper provides a geological overview of the Argentine Puna through a brief analysis of its sedimentary and magmatic stratigraphy, diastrophic episodes and tectonic arrangement, which allow the main mineralization events that occurred during the Cenozoic to be located in time and space. The intensive, widespread magmatic activity that took place in the region, particularly during various pulses in the Miocene, is responsible for generating various types of metal ore deposits hosted directly in the magmatic bodies, whether intrusive, flows and/or pyroclastic mantles, or in the host rock. The development of post-Inca continental sedimentary basins, their distribution areas, associated metal ore deposits and prospective possibilities are also discussed. Finally, the genesis of the metal ore deposits in the Argentine Puna is analyzed, in close relationship to the diastrophic phases and the evolution of associated magmatism. The following Metallogenic Intervals and Events are recognized: i) Late Eocene-Late Oligocene Metallogenic Interval, between the Inca and Pehuenche phases: First late Eocene- middle Oligocene Mineralizing Event. ii) Early Miocene-Middle Miocene Metallogenic Interval, between the Pehuenche and initial Quechua phases: First early Miocene Mineralizing Event; Second middle Miocene Mineralizing Event. iii) Late Miocene-Late Pliocene Metallogenic Interval, between the initial Quechua and Diaguita phases: First late Miocene Mineralizing Event; Second Pliocene Mineralizing Event. iv) Pleistocene-Holocene Metallogenic Interval, post-Diaguita phase: First Pleistocene- Holocene Mineralizing EventSe brinda un panorama geológico de la Puna argentina a través de un breve análisis de la estratigrafía sedimentaria y magmática, de los episodios diastróficos y de la disposición tectónica que permiten ubicar en el tiempo y en el espacio los principales eventos mineralizantes ocurridos durante el Cenozoico. La intensa y amplia actividad magmática que tuvo lugar en la región, especialmente a través de varios pulsos durante el Mioceno, es la responsable de la generación de diversos tipos de depósitos metalíferos que se alojan directamente en los cuerpos magmáticos, sean intrusivos, coladas y/o mantos piroclásticos, o en las rocas de caja. Se discute asimismo el desarrollo de las cuencas sedimentarias continentales posincaicas, sus áreas de distribución, los depósitos metalíferos asociados y las posibilidades prospectivas. Finalmente se realiza un análisis de la génesis de los depósitos metalíferos en estrecha relación con las fases diastróficas y la evolución del magmatismo asociado acontecidos en la Puna argentina. Se reconocen los Intervalos y Sucesos Metalogenéticos siguientes: i) Intervalo Metalogenético Eoceno Superior-Oligoceno Superior, entre las fases Incaica y Pehuenche: Primer Suceso Mineralizante Eoceno Superior-Oligoceno Medio. ii) Intervalo Metalogenético Mioceno Inferior-Mioceno Medio, entre las fases Pehuenche y Quechua inicial: Primer Suceso Mineralizante Mioceno Inferior; Segundo Suceso Mineralizante Mioceno Medio. iii) Intervalo Metalogenético Mioceno Superior-Plioceno Superior, entre las fases Quechua inicial y Diaguita: Primer Suceso Mineralizante Mioceno Superior; Segundo Suceso Mineralizante Plioceno. iv) Intervalo Metalogenético Pleistoceno-Holoceno, posfase Diaguita: Primer Suceso Mineralizante Pleistoceno-Holoceno.Fil: Gorustovich, Sergio Antonio. Comisión Nacional de Energía Atómica; ArgentinaFil: Monaldi, Cesar Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; ArgentinaFil: Salfity, Jose Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina. Universidad Nacional de Salta; Argentin
Conodonts from the Cambrian-Ordovician Boundary in the Cordillera Oriental, NWArgentina
Get PDFThe Cambrian-Ordovician boundary in NW Argentina was originally proposed for the lower upper section of the Cardonal Formation in the Amarilla Creek, Cajas Range, Cordillera Oriental of Jujuy, based on the first appearance of the conodont Cordyloduslindstromi. After the finding of the index fossil Iapetognathus, the intersystemic boundary in this stratigraphic unit was recently verified.Through the upper 42 meters of the Cardonal Formation, which is 160 m in total thickness, conodonts of the Cordylodus lindstromi,Iapetognathus and Cordylodus angulatus zones were recovered. The lower upper section of the formation where is located the referred boundary consists of grey-greenish shales interbedded with calcareous sandstones that represent an upper off shore environment which deepens upwards. The associated species belong to the genera Acanthodus, Cordylodus, Eoconodontus, Furnishina, Iapetognathus,Orminskia, Phakelodus, Problematoconites, Proconodontus and Teridontus. Importantly, the index species Iapetognathus fluctivagus andI. jilinensis were documented for the region in this study. The conodont species are mostly cosmopolitan, integrating a local fauna that is interpretedas representing the Transitional Faunal Realm of Mid latitudes in the ColdWater Domain or to the lately defined Southwestern Gondwana Province from the Cold Domain in the Shallow-Sea Realm. The conodont elements exhibit a black color (CAI 5 = 300º and480º), with a significant alteration caused by a Jurassic-Cretaceous boundary hydrothermal influence.Fil: Albanesi, Guillermo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; ArgentinaFil: Giuliano, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Pacheco, Fernanda Elena. Secretaría de Estado de Minería de la Provincia de Santa Cruz. Gestión Ambiental; ArgentinaFil: Ortega, Gladys del Carmen. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geologia Básica y Aplicada; ArgentinaFil: Monaldi, Cesar Ruben. Universidad Nacional de Salta. Facultad de Ciencias Naturales; Argentin
An Early Ordovician conodont fauna from the Santa Rosita Formation at its type area in the Santa Victoria Range, Cordillera Oriental, Northwestern Argentina
Get PDFThe Cambrian - Lower Ordovician stratigraphic units from the Cordillera Oriental were originally defined in the Santa Victoria Range, Salta Province, northwestern Argentina, however, the extensive outcrops of this region lack detailed biostratigraphic studies. We describe and analyse the first reported conodont fauna from the Santa Rosita Formation at its type area, which produced significant biostratigraphic information. Over 4,500 well-preserved conodont elements were recovered from outcrops of the Santa Rosita Formation at the southern margin of the Santa Victoria River, near the homonymous locality. Collected specimens exhibit a CAI 3 and correspond to the Paltodus deltifer deltifer Subzone of the P. deltifer Zone (middle Tremadocian, Tr2). A number of species are described for the genera Acanthodus, Acodus, Decoriconus, Drepanodus, Drepanoistodus, Filodontus, Granatodontus, Hammannodus, Iapetonudus, Kallidontus, Paltodus, Paroistodus, Teridontus, Tilcarodus, Utahconus, Variabiloconus, Gen. and sp. indet., the protoconodont Phakelodus and the paraconodont Coelocerodontus. Two new conodont species, Drepanoistodus andinus Voldman, Zeballo and Albanesi and Filodontus carolinae Voldman, Albanesi and Zeballo, are diagnosed herein. The studied assemblages include conodont species of wide intercontinental distribution as well as endemic forms from the Central Andean Basin, which characterize a faunal province with a particular signature from the Shallow Water Realm.Fil: Voldman, Gustavo Gabriel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Albanesi, Guillermo Luis. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Monaldi, Cesar Ruben. Universidad Nacional de Salta. Facultad de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zeballo, Fernando Javier. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Paleontología; Argentin
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