Revised stratigraphic framework of the Cretaceous in the Bajo Grande area (Argentinean Patagonia) inferred from new U–Pb ages and palynology

Passalia, Mauro Gabriel; Llorens, Magdalena; Césari, Silvia N.; Limarino, Carlos Óscar; Loinaze, Valeria Susana Pérez; Vera, Ezequiel Ignacio

doi:10.1016/j.cretres.2015.11.004

Cited by 28 publications

(22 citation statements)

References 33 publications

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“…The age of the deposition of the Anfiteatro de Ticó Formation, where Eobowenia is found, is very well constrained to 118.23 ± 0.09 Ma [63] or 116.85 ± 0.26 Ma [64] representing an Aptian (Lower Cretaceous) age, which is compatible with the ages inferred for the stem of Bowenia by Nagalingum et al [17] using a relaxed log-normal clock and by Condamine et al [16] using the favoured birth-death prior with both the calibration implemented, but is older than the dates retrieved by Salas-Leiva et al [7] (Table 2). This probable early divergence of the genus Bowenia is, however, compatible with the phylogenetic placement retrieved by the multilocus analysis of Salas-Leiva et al [7], which sees Bowenia as sister to all the other Zamiaceae apart from Dioon.…”

Section: Discussionmentioning

confidence: 99%

Eobowenia gen. nov. from the Early Cretaceous of Patagonia: indication for an early divergence of Bowenia?

Coiro

Pott

2017

BMC Evol Biol

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BackgroundEven if they are considered the quintessential “living fossils”, the fossil record of the extant genera of the Cycadales is quite poor, and only extends as far back as the Cenozoic. This lack of data represents a huge hindrance for the reconstruction of the recent history of this important group. Among extant genera, Bowenia (or cuticles resembling those of extant Bowenia) has been recorded in sediments from the Late Cretaceous and the Eocene of Australia, but its phylogenetic placement and the inference from molecular dating still imply a long ghost lineage for this genus.ResultsWe re-examine the fossil foliage Almargemia incrassata from the Lower Cretaceous Anfiteatro de Ticó Formation in Patagonia, Argentina, in the light of a comparative cuticular analysis of extant Zamiaceae. We identify important differences with the other member of the genus, viz. A. dentata, and bring to light some interesting characters shared exclusively between A. incrassata and extant Bowenia. We interpret our results to necessitate the erection of the new genus Eobowenia to accommodate the fossil leaf earlier assigned as Almargemia incrassata. We then perfom phylogenetic analyses, including the first combined morphological and molecular analysis of the Cycadales, that indicate that the newly erected genus could be related to extant Bowenia.Conclusion Eobowenia incrassata could represent an important clue for the understanding of evolution and biogeography of the extant genus Bowenia, as the presence of Eobowenia in Patagonia is yet another piece of the biogeographic puzzle that links southern South America with Australasia.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-017-0943-x) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Eobowenia gen. nov. from the Early Cretaceous of Patagonia: indication for an early divergence of Bowenia?

Coiro

Pott

2017

BMC Evol Biol

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“…The finding of a local angular unconformity in the Madre e Hija range separating two sedimentary successions with a different degree of contractional deformation in the Bajo Tigre Formation (~116 Ma, Passalia et al, ; Figure a) indicates that compression took place in Late Aptian times. The development of growth strata in the upper sedimentary interval of the Bajo Tigre Formation linked to Madre e Hija thrust front supports the syncontractional nature of the upper part of this unit (Figure b).…”

Section: Discussionmentioning

confidence: 97%

“…More recently, Cladera et al () assigned these deposits to a higher rank unit, the Baqueró Group, with three formations: the Anfiteatro de Ticó Formation, equivalent to the lower member of Archangelsky (), and the Bajo Tigre and Punta del Barco formations, corresponding to the upper member of Archangelsky (; Figure d). Recent U/Pb ages of 118.23 ± 0.09 Ma (Césari et al, ), 116.85 ± 0.26 Ma (Pérez Loinaze et al, ), and 114.67 ± 0.18 Ma (Passalia et al, ) for the Anfiteatro de Ticó, Bajo Tigre, and Punta del Barco formations, respectively, constrained the deposition of the Baqueró Group to the late Aptian (Figure d).…”

Section: Geological Overviewmentioning

confidence: 92%

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 result is that laminae becomes coarser grained down slope (fining upward sorting) and towards its inclined, basal surface (normally graded). Isolated, larger grains also rest on the inclined, basal surface along lee slopes, and the latter reflect subsequent deposition by grainfall (e.g., Passalia et al, 2016). Nevertheless, in sandy gravel sediments of subaqueous dunes, the cross-stratification mainly consists of grain flow deposits with little or no grain fall deposition on most of their lee faces (Kleinhans, 2004), suggesting that the sediment was delivered in pulses; rolling grain deposits for the coarsest sediments, however, are also common (Kleinhans, 2004).…”

Section: Implications Of Cross-bedding Stylesmentioning

confidence: 99%

Depositional architecture and peculiar sedimentary features of late Cretaceous Utrillas Formation at Tamajón (Guadalajara, Spain)

García-Hidalgo¹,

Gil-Gil

Segura

et al. 2016

Journal of Iberian Geology

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The Utrillas Formation represents clastic wedges that accumulated in relation to continental-coastal areas of Iberian Basin during the worldwide Late Cretaceous sea-level rise. At the Tamajón outcrop the Late Cenomanian Utrillas wedges are composed of four facies associations (FA1 to FA4), which unconformably overlay Triassic deposits. Basal sediments (FA1) are interpreted as high energy, braided fluvial deposits, characterized by coarse-grained (conglomerate-sandstone) facies; which grade upwards to tide-influenced, estuarine sedimentation (sandstones and mudstones with inclined heterolithic stratification, FA2), and then to high-energy, coastal sheet and channelled sandstones with different tidal features (FA3); and finally, to fine-grained (mudstones and minor burrowed sandstones) of an offshore marine associations (FA4). The depositional architecture based in the presence and hierarchy of several ranks of bounding surfaces and the overall upward-fining succession show the long term retrogradational trend of these facies associations. Peculiar sedimentary features of these sediments are 1) the presence of large-scale, single sets of cross beds infilling large erosive channels, which are tidal in origin. 2) The size and length of the cross-bedding defined by couplets of different grain size; here interpreted as originated by flow unsteadiness in relation to changing tides. And 3) an unusual association of ironstones, wrinkle structures and vertebrate tracks with microbial mats and penecontemporaneous iron encrusting allowing track preservation in the sedimentary record.Keywords: continental-coastal facies, large-scale channels, ferruginous crusts, wrinkle marks, vertebrate tracks, Cenomanian. ResumenLa Formación Utrillas está compuesta por una serie de cuñas clásticas que se depositaron en las áreas continentales y costeras de la Cuenca Ibérica durante el ascenso eustático global del Cretácico Superior. En el afloramiento de Tamajón las cuñas del Cenomaniense Superior de la Formación Utrillas están compuestas por 4 asociaciones de facies (FA1 a FA4), que se disponen discordantes sobre materiales triásicos. Los sedimentos basales (FA1) se interpretan como depósitos de sistemas fluviales de tipo braided, de alta energía, caracterizados por facies de grano grueso (conglomerados y areniscas); que pasan hacia techo a facies estuarinas con influencia mareal (areniscas y lutitas con estratificación heterolítica inclinada, FA2), y estas a areniscas tabulares y canalizadas costeras de alta energía que presentan diferentes características mareales (FA3); y, finalmente la sucesión da paso a una asociación marina somera (FA4), de grano fino y baja energía (lutitas con areniscas bioturbadas subordinadas). La arquitectura deposicional se basa en la presencia y jerarquía de varios rangos de superficies erosivas y la tendencia granodecreciente general de la sucesión, que caracteriza la tendencia retrogradacional general de esas asociaciones de facies. Los materiales estudiados presentan una serie de características se...

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Revised stratigraphic framework of the Cretaceous in the Bajo Grande area (Argentinean Patagonia) inferred from new U–Pb ages and palynology

Cited by 28 publications

References 33 publications

Eobowenia gen. nov. from the Early Cretaceous of Patagonia: indication for an early divergence of Bowenia?

Eobowenia gen. nov. from the Early Cretaceous of Patagonia: indication for an early divergence of Bowenia?

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

Depositional architecture and peculiar sedimentary features of late Cretaceous Utrillas Formation at Tamajón (Guadalajara, Spain)

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