Mercedes Barros

Universidad Nacional del Sur

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Daniel A. Gregori

Universidad Nacional del Sur

Leonardo Benedini

Universidad Nacional del Sur

Leonardo Strazzere

Universidad Nacional del Sur

Cecilia Pavón Pivetta

Centro Científico Tecnológico - Bahía Blanca

Paulo Marcos

Consejo Nacional de Investigaciones Científicas y Técnicas

Mauro César Geraldes

Universidade do Estado do Rio de Janeiro

José Kostadinoff

Universidad Nacional del Sur

Anderson Costa dos Santos

Universidade do Estado do Rio de Janeiro

Nicolás Scivetti

National University of Patagonia San Juan Bosco

Marcos E. Bahía

Universidad Nacional del Sur

Cooperative Institutions

Universidad Nacional del Sur

Centro Científico Tecnológico - Bahía Blanca

Consejo Nacional de Investigaciones Científicas y Técnicas

Centro Científico Tecnológico - Tucumán

Centro Científico Tecnológico - San Juan

Universidade do Estado do Rio de Janeiro

Universidade Federal do Rio de Janeiro

National University of Río Negro

University of Buenos Aires

Geological Survey of Ireland

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Early Jurassic tectonomagmatic stages in the western North Patagonian Region, Argentina: insights from the Comallo volcanic sedimentary complex

Figshare (2023)

Mercedes Barros Cecilia Pavón Pivetta Daniel A. Gregori Leonardo Benedini Leonardo Strazzere

The Comallo volcanic sedimentary Complex in the western North Patagonian Region begins with the development and collapse of Plinian-type eruptive columns of rhyolitic and dacitic composition associated to vent at approximately 192 Ma. Synchronous deposits are originating in alluvial and lagoon environments. The ƐHf(t) values obtained in zircon grains indicate possible derivation by melting Paleoproterozoic and Mesoproterozoic crust. Upwards in the sequence appears basaltic and andesitic lava flows, as well as pyroclastic deposits produced during the eruptions. This volcanism is related to sustained pyroclastic fountains with a U-Pb zircon age of 185 Ma. The volcanic rocks were possibly derived from Paleoproterozoic, Mesoproterozoic, and Neoproterozoic crust affected by juvenile magmas in volcanic-arc environments. Chemical and isotopic variations are mainly due to changes in the local and regional tectonic conditions, the thickness of the continental crust, as well as the dip and age of the subducted oceanic crust.

10.6084/m9.figshare.23566950

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Evolution of the Jurassic Comallo volcanic sedimentary complex in the western North Patagonian Massif, Rio Negro province, Argentina

International Geology Review (2020)

Mercedes Barros Daniel A. Gregori Leonardo Benedini Paulo Marcos Leonardo Strazzere

Here we define the Comallo volcanic sedimentary complex of the western North Patagonian Massif. It is composed by two members that include 9 lithofacies and 7 facies associations. The lower member is represented by massive and stratified lapilli tuffs, lithic and tuffaceous breccias, coherent andesite-dacite lava-flows, andesitic breccias, and massive crystalline limestones. The upper member consists of red conglomerates, parallel and cross-stratification sandstones, and mudstones. The lower member is interpreted as having been deposited by dilute and dense pyroclastic currents, block and ash deposits and lava-flow, and hypersaline lacustrine environments. The upper member is considered to have been deposited in fluviatile environments. A new U-Pb age of 192.0 ± 3.0 Ma (Sinemurian) was obtained for this complex. It is coeval with several volcanic sedimentary units that crop out along the western North Patagonian Massif, the Neuquén basin and the Extraandean Chubut in pull-apart or rift depocentres. The movements of the NW-SE strike-slip faults that border the northern and southern limits of the Comallo depocentre made possible the development of a pull-apart basin as well as the volcanism and the fluvial system. This and other coeval units were deposited in similar environmental conditions along the North Patagonian Massif, the Neuquén basin and the extraandean Chubut, indicating a similar tectonomagmatic setting, in a tensional rear-arc during Lower Jurassic times.

Massif

Breccia

Lapilli

Stratovolcano

10.1080/00206814.2020.1731854

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Citations (14)

Pennsylvanian glacimarine sedimentation in the Cushamen Formation, western North Patagonian Massif

Geoscience Frontiers (2017)

Paulo Marcos Daniel A. Gregori Leonardo Benedini Mercedes Barros Leonardo Strazzere

The metasedimentary sequence of the Cushamen Formation in the western North Patagonian Massif is 540 m thick and comprises six sedimentary lithofacies associations related to a glacimarine environment. Four of these lithofacies represent distal glacimarine environments, whereas another one was deposited in proximal glacimarine environments, and the last includes subglacial environments. The organization and configuration of these lithofacies associations represent the advance and retreat of the glacier masses. The maximum glacial advance is correlatable with the G2 glacial interval of the Pennsylvanian Pampa de Tepuel, Las Salinas and Valley Chico, formations of the Extraandean Chubut, and the southern part of Neuquén Cordillera. Contemporaneously, in southern Chile there are marine and glacimarine sediments. The chronostratigraphic relationships between the Silurian to Permian units allow five paleogeographic stages to be distinguished. The middle Silurian–late Devonian igneous rocks represent the first magmatic stage. The second stage, which is transitional to the first, is represented by a marine basin that includes the late Devonian–early Carboniferous Esquel and Río Pescado formations and the Llanquihue Complex. The third stage (early–late Carboniferous) includes granitoids of the second magmatic event that partially overlapped the first magmatic igneous belt. The fourth stage belongs to the late Carboniferous sedimentation of the Cushamen and equivalent formations. The extended early Permian magmatism was the last Paleozoic event in the studied area.

Massif

Devonian

10.1016/j.gsf.2017.05.005

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Citations (15)

The Mencué Batholith: Permian episodic arc-related magmatism in the western North Patagonian Massif, Argentina

Figshare (2020)

Daniel A. Gregori Leonardo Strazzere Mercedes Barros Leonardo Benedini Paulo Marcos

The Mencué Batholith, western North Patagonian Massif, includes three major bodies. The Mencué Granodiorite, Cura Lauquén Granite and La Blancura Syenogranite. There are dikes of granitic and basaltic rocks cutting the above-cited rocks. The Mencué Batholith represents several episodes of magmatism, with ages varying between 294 and 239 Ma. The Mencué Granodiorite and the Cura Lauquén Granite are solid-state deformed and are S-type. They have high-K and normal calc-alkaline affinities. These rocks contain significant quantities of subduction-zone chemical components that decrease towards younger lithofacies. La Blancura Syenogranite lack subduction zone chemical components and represent A-type granite, typical of within-plate magmatism. The partial melting of metapelites could be the process of formation of these bodies. The older lithofacies of the Mencué Batholith, found westernmost, display a stronger deformation, but there is a progressive eastward change to younger and mildly deformed bodies and even non-deformed bodies. We conclude that the evolution of the Mencué Batholith start in the Sakmarian-Roadian (Early Permian) period. At this time, a subduction zone was active to the west and its thermal influence affected sedimentary or metamorphic rocks producing S-type granites During the Wordian and Capitanian, (Middle Permian) periods, the Mencué Batholith was mildly deformed, possibly in the process of the vanishing of the deformation and has a minor subduction chemical signature. Between the Wuchiapingian and Olenekia periods, the alkaline facies of the Mencué Batholith show an absence of deformation and the characteristics of within-plate magmatism. The Early Permian magmatic events in the western North Patagonian Massif are represented by the older bodies of the Mencué Batholith and were produced by subduction in the western margin of the Gondwanan continent. The Late Permian-Early Triassic magmatic events show a noticeable decreasing influence of subduction and an increasing influence of within-plate chemical components.

Batholith

Massif

10.6084/m9.figshare.11547192

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Late Paleozoic geodynamic evolution of the western North Patagonian Massif and its tectonic context along the southwestern Gondwana margin

Lithos (2020)

Paulo Marcos Cecilia Pavón Pivetta Leonardo Benedini Daniel A. Gregori Mauro César Geraldes

Massif

Basement

Greenschist

10.1016/j.lithos.2020.105801

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Citations (24)

Preandean geological configuration of the eastern North Patagonian Massif, Argentina

Geoscience Frontiers (2013)

Daniel A. Gregori José Kostadinoff Guillermina Alvarez Ariel Raniolo Leonardo Strazzere

The Preandean geological configuration of the eastern North Patagonian Massif is established through the use of geological and geophysical analysis.The positive gravity anomalies located near the Atlantic coast are due to 535 and 540 Ma old rocks belonging to the Pampean Orogeny (Precambrianemiddle Cambrian), which are widely recognized in central and northern Argentina.The Famatinian Cycle (OrdovicianeDevonian) is represented by a SilurianeDevonian marine basin equivalent to those of eastern-central Argentina and South Africa, and which was deformed at the end of the Devonian by an wEeW to WNWeESE compressional event, part of the Famatinian Orogeny.Containing strong gravity gradients, the NWeSE belt is coincident with fault zones which were originated during the Gondwanide Orogeny.This event also produced NWeSE overthrusting of the SilurianeDevonian sequences and strike-slip faults that displaced blocks in the same direction.This deformation event belongs to the Gondwanide Orogeny that includes movements related to a counterclockwise rotation of blocks in northern Patagonia.The strong negative anomalies located in the western part of the area stem from the presence of rocks of the Jurassic Cañadón Asfalto basin interbedded in the Marifil Complex.These volcaniclastic sequences show mild deformation of accommodation zones in a pre-Jurassic paleorelief.

Orogeny

Massif

Devonian

Clockwise

10.1016/j.gsf.2013.01.001

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Citations (19)

The Gondwana Orogeny in northern North Patagonian Massif: Evidences from the Caita Có granite, La Seña and Pangaré mylonites, Argentina

Geoscience Frontiers (2015)

Daniel A. Gregori Bernhardt Saini‐Eidukat Leonardo Benedini Leonardo Strazzere Mercedes Barros

Structural analyses in the northern part of the North Patagonia Massif, in the foliated Caita Có granite and in La Seña and Pangaré mylonites, indicate that the pluton was intruded as a sheet-like body into an opening pull-apart structure during the Gondwana Orogeny. Geochronological studies in the massif indicate a first, lower to middle Permian stage of regional deformation, related to movements during indentation tectonics, with emplacement of foliated granites in the western and central areas of the North Patagonian Massif. Between the upper Permian and lower Triassic, evidence indicates emplacement of undeformed granitic bodies in the central part of the North Patagonian Massif. A second pulse of deformation between the middle and upper Triassic is related to the emplacement of the Caita Có granite, the development of mylonitic belts, and the opening of the Los Menucos Basin. During this pulse of deformation, compression direction was from the eastern quadrant.

Massif

Mylonite

Orogeny

Plutonism

10.1016/j.gsf.2015.06.002

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The basins of the northwest sector of the Province of Buenos Aires

Daniel A. Gregori Daniel E. Robles José Kostadinoff Guillermina Alvarez Ariel Raniolo

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Lower Jurassic felsic diatreme volcanism recognized in central Patagonia as evidence of along-strike rift segmentation