U–Pb zircon ages from the northern Austral basin and their correlation with the Early Cretaceous exhumation and volcanism of Patagonia

Ghiglione, Matías C.; Naipauer, Maximiliano; Sue, Christian; Barberón, Vanesa; Valencia, Víctor A.; Aguirre–Urreta, Beatriz; Ramos, Víctor A.

doi:10.1016/j.cretres.2015.02.006

Cited by 65 publications

(77 citation statements)

References 53 publications

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“…Previously published U‐Pb geochronology suggests that the foreland phase of the MAB initiated between 115 Ma and 100 Ma in the northernmost Austral sector (Ghiglione et al ., ; Malkowski et al ., ,b). This initial foreland phase is recorded in the northernmost part of the basin (47.5° S) by shallow marine to deltaic facies (Ghiglione et al ., ) that transition southward into deep‐marine facies (Figs and a; Malkowski et al ., ). This transition may occur as far north as 49.3° S, but is definitive at 49.7° S. Radiometric age controls support the original model for the depositional history of the MAB, or what we refer to as the deep‐marine model.…”

Section: Discussionmentioning

confidence: 99%

“…a, inset). The tectonic regime transitioned from extensional to compressional at approximately 115 Ma, initiating phase 2 of the basin history with the formation of the MAB on top of the RVB (Wilson, ; Ghiglione et al ., ; Malkowski et al ., ).…”

Section: Basin Historymentioning

confidence: 97%

“…The MAB progressively shifted to compression southward, in the opposite direction that the RVB opened. Initial foreland sedimentation began in the northernmost Austral sector as early as 115 Ma (Ghiglione et al ., ; Malkowski et al ., ) and progressed south to the Magallanes sector by 93 Ma (Fildani et al ., ; Bernhardt et al ., ). Palaeocurrent and provenance data from the foreland basin fill show that sediment transport was dominantly longitudinal, and mean palaeodispersal was north to south along the axis of the basin following delivery of sediment to the basin by transverse depositional systems (Bernhardt et al ., ; Malkowski et al ., , ).…”

Section: Basin Historymentioning

confidence: 99%

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Refining stratigraphy and tectonic history using detrital zircon maximum depositional age: an example from the Cerro Fortaleza Formation, Austral Basin, southern Patagonia

2018

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The north–south trending, Late Cretaceous to modern Magallanes–Austral foreland basin of southernmost Patagonia lacks a unified, radiometric, age‐controlled stratigraphic framework. By simplifying the sedimentary fill of the basin to deep‐marine, shallow‐marine and terrestrial deposits, and combining 13 new U‐Pb detrital zircon maximum depositional ages (DZ MDAs) with published DZ MDAs and U‐Pb ash ages, we provide the first attempt at a unified, longitudinal stratigraphic framework constrained by radiometric age controls. We divide the foreland basin history into two phases, including (1) an initial Late Cretaceous shoaling upward phase and (2) a Cenozoic phase that overlies a Palaeogene unconformity. New DZ samples from the shallow‐marine La Anita Formation, the terrestrial Cerro Fortaleza Formation and several previously unrecognized Cenozoic units provide necessary radiometric age controls for the end of the Late Cretaceous foreland phase and the magnitude of the Palaeogene unconformity in the Austral sector of the basin. These samples show that the La Anita and Cerro Fortaleza Formations have Campanian DZ MDAs, and that overlying Cenozoic strata have Eocene to Miocene DZ MDAs. By filling this data gap, we are able to provide a first attempt at constructing a basinwide, age‐controlled stratigraphic framework for the Magallanes–Austral foreland basin. Results show southward progradation of shallow marine and terrestrial environments from the Santonian through the Maastrichtian, as well as a northward increase in the magnitude of the Palaeogene unconformity. Furthermore, our new age data significantly impact the chronology of fossil flora and dinosaur faunas in Patagonia.

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Section: Discussionmentioning

confidence: 99%

Section: Basin Historymentioning

confidence: 97%

Section: Basin Historymentioning

confidence: 99%

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Refining stratigraphy and tectonic history using detrital zircon maximum depositional age: an example from the Cerro Fortaleza Formation, Austral Basin, southern Patagonia

2018

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“…This suggests a more complex tectonic evolution than previously acknowledged for the initial stages of Patagonian broken foreland development. From the analysis of these findings several contractional stages could be inferred in addition to previously identified early Aptian (~122–118 Ma) and Neogene stages (Ghiglione et al, ; Giacosa et al, ; Homovc & Constantini, ).…”

Section: Discussionmentioning

confidence: 60%

Cretaceous Intraplate Contraction in Southern Patagonia: A Far‐Field Response to Changing Subduction Dynamics?

et al. 2018

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The origin, extent, and timing of intraplate contraction in Patagonia are among the least understood geological processes of southern South America. Particularly, the intraplate Deseado fold‐thrust belt (FTB), located in the Patagonian broken foreland (47°–48°30′S), is one of the most enigmatic areas. In this belt, time constraints on tectonic events are limited and synorogenic deposits have not been documented so far. Furthermore, the driving mechanism for intraplate contraction remains unknown. In this study, we carried out a structural and sedimentological analysis. We report the first syntectonic deposits in this area in the Baqueró (Aptian) and Chubut (Cenomanian/Campanian) groups and a newly found unit referred to as the Albian beds (109.9 ± 1.5 Ma). Thus, several contractional stages in late Aptian, Albian, and Cenomanian‐Campanian are then inferred. We suggest that the Deseado FTB constituted the southernmost expression of the early Patagonian broken foreland in Cretaceous times. Additionally, we analyzed the spatiotemporal magmatic arc behavior as a proxy of dynamic changes in the Andean subduction during determined stages of intraplate contraction. We observe a significant arc broadening from ~121 to 82 Myr and magmatic quiescence after ~67 Ma. This is interpreted as a slab shallowing to flattening process. Far‐field tectonic forces would have been produced by increased plate coupling linked to the slab flattening as indirectly indicated by the correlation between Cretaceous arc expansion and intraplate contraction. Finally, the tectonic evolution of the Deseado FTB favors studies supporting inception of Andean shortening since Cretaceous times.

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“…The Lower Cretaceous clastic succession begins with the transgressive sandstones of the Pueyrredón Group that includes the basal sandstones of the Springhill Formation, which are in turn overlain by the marine black shales of the Río Mayer Formation. A series of litoral and deltaic sandstones of the Río Belgrano Formation prograding to the south overlie the Río Mayer Formation and mark the beginning of the foreland stage of the basin (Giacosa and Franchi, 2001;Arbe, 2002;Ghiglione et al, 2015). These deposits are covered in turn by Aptian-Cenomanian fluvial tuffaceous sandstone and conglomerate beds of the Río Tarde Formation.…”

Section: Stratigraphic Frameworkmentioning

confidence: 99%

Estratigrafía de Sr y evolución sedimentaria de los depósitos marinos del Mioceno temprano en el antepaís del norte de la Cuenca Austral (o Magallanes), Argentina.

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et al. 2015

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ABSTRACT. Early Miocene shallow marine deposits in the region of Lago Posadas-Meseta Belgrano (Argentina) represent part of the "Patagoniense" transgression, an Atlantic marine incursion that flooded large part of Patagonia, including the Austral (foreland) Basin (southern Patagonia). These deposits, referred as El Chacay (Argentina) or Guadal (Chile) formations, and the transition to the overlying Santa Cruz Formation were divided into six facies: subtidal sandbars, shallow marine sandy deposits, muddy shelf deposits, estuarine complex deposits, fluvial channels and fluvial floodplains. These are arranged in a general transgressive-regressive cycle, subdivided into two stratigraphic sequences, separated by a major erosional surface. 87Sr/ 86Sr ages from shell carbonate in eight oysters yielded an age range of 20.3 to 18.1 Ma for these "Patagoniense" deposits. Correlation with other dated "Patagoniense" sections in southern Patagonia, like those at Lago Argentino or Comodoro Rivadavia, indicates that they belong to a single transgression that flooded several Patagonian basins approximately at the same time. Eustasy, flexural subsidence created by tectonic loading in the adjacent fold-and-thrust belt, and basin floor paleo-topography controlled the duration of the depositional event and the sedimentation style of these shallow marine deposits. Keywords: Patagoniense, Patagonia, Sr-stratigraphy, Transgression, Sedimentology. RESUMEN. Estratigrafía de Sr y evolución sedimentaria de los depósitos marinos del Mioceno temprano en el antepaís del norte de la Cuenca Austral (o Magallanes), Argentina. Los depósitos marino-someros del Mioceno temprano de la región del Lago Posadas-Meseta Belgano representan parte de la transgresión "Patagoniense", una incursión marina atlántica que invadió gran parte de la Patagonia, incluyendo la Cuenca de antepaís Austral (Patagonia austral). Estos depósitos, referidos como formaciones El Chacay (Argentina) y Guadal (Chile), y su transición a la suprayacente Formación Santa Cruz, fueron divididos en seis facies: barras submareales, depósitos arenosos marino-someros, depósitos fangosos de plataforma, complejo estuarino, canales f luviales y planicie de inundación. Estas facies muestran un arreglo general transgresivo-regresivo, el que puede ser subdividido en dos secuencias estratigráficas separadas por una superficie erosiva. Resultados de ocho edades 87 Sr/ 86Sr de carbonato tomado de valvas de ostras dieron un rango entre 20,3 Ma y 18,1 Ma para estos depósitos Patagonienses. La correlación con sucesiones equivalentes de edad conocida en la Patagonia Austral, como las del Lago Argentino o Comodoro Rivadavia, indican que estas pertenecen a una misma transgresión que inundó gran parte de la Patagonia aproximadamente al mismo tiempo. La eustacia, la subsidencia flexural creada por carga tectónica en la faja corrida y plegada adyacente, y la paleotopografía del fondo de la cuenca, controlaron la duración del evento depositacional y el estilo de sedimentación estos depósitos marino-somer...

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U–Pb zircon ages from the northern Austral basin and their correlation with the Early Cretaceous exhumation and volcanism of Patagonia

Cited by 65 publications

References 53 publications

Refining stratigraphy and tectonic history using detrital zircon maximum depositional age: an example from the Cerro Fortaleza Formation, Austral Basin, southern Patagonia

Refining stratigraphy and tectonic history using detrital zircon maximum depositional age: an example from the Cerro Fortaleza Formation, Austral Basin, southern Patagonia

Cretaceous Intraplate Contraction in Southern Patagonia: A Far‐Field Response to Changing Subduction Dynamics?

Estratigrafía de Sr y evolución sedimentaria de los depósitos marinos del Mioceno temprano en el antepaís del norte de la Cuenca Austral (o Magallanes), Argentina.

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