An updated scenario for the end-Permian crisis and the recovery of Triassic land flora in Argentina

Bodnar, Josefina; Coturel, Eliana Paula; Falco, Juan Ignacio; Beltrán, Marisol

doi:10.1080/08912963.2021.1884245

Cited by 14 publications

(6 citation statements)

References 89 publications

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“…Dicroidium-type fossil flora imprints and tetrapod ichnites were described from different localities in the basin, leading to the assignation of a Changhsingian(?) to Olenekian (Lower Triassic) age (Bodnar et al 2021;Citton et al 2021).…”

Section: C2 Stratigraphy Of the Los Menucos Basin (Lmb)mentioning

confidence: 99%

“…The lower Aguada de la Mula Member is dominated by gravelly sandstone, medium to fine sandstone, and mudstone, deposited in fluvial channels and on floodplains (Labudía & Bjerg, 2001). The upper El Pilquin Member is exclusively composed of ash fall deposits, which contain Dicroidium-type flora and ichnites (Bodnar et al 2021;Citton et al 2021). The upper Sierra Colorada Formation is composed of three ignimbritic pulses, the first one only recognized at Puesto Vera, and the upper two well developed throughout the basin.…”

Section: C2 Stratigraphy Of the Los Menucos Basin (Lmb)mentioning

confidence: 99%

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The origin of Patagonia: insights from Permian to Middle Triassic magmatism of the North Patagonian Massif

et al. 2022

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We conducted a U–Pb–Hf isotope study on zircon crystals from ignimbrites of the Changhsingian to Olenekian (253–248 Ma) Los Menucos Basin in the North Patagonian Massif (NPM), Argentina, in order to evaluate the age and petrogenesis of the magmas. Additionally, a compilation of whole-rock geochemistry and U–Pb–Hf in zircon isotope data for the Permian to Middle Triassic rocks of the NPM, for comparison with our data, was made to assess whether Patagonia would have been an exotic terrane accreted to SW Gondwana during the late Palaeozoic. We interpret the available U–Pb–Hf data to suggest that northern Patagonia experienced eastward arc expansion from the early Permian, about 273 Ma ago. This ∼820 km arc expansion event involved crustal shortening and magmatism with high-silica adakitic affinity, resulting in Hf-isotopic pull-down. At 253 Ma, slab steepening became associated with the coeval emplacement of ignimbrites of the Los Menucos Basin, which involved post-orogenic to intraplate magmatism. During the Middle Triassic, a slab break-off triggered uplift and basaltic underplating, promoting the emplacement of dike swarms with C-type adakitic signature at 246–244 Ma. The Hf isotope data for SW Gondwana for the same period indicate distinct trends that are explained here by differential slab roll-back since the Guadalupian, in a slab-tearing setting. Therefore, Permian to Middle Triassic magmatism is interpreted as having been associated with an eastward-directed proto-Pacific subduction system, which ultimately supports an autochthonous origin for Patagonia.

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Section: C2 Stratigraphy Of the Los Menucos Basin (Lmb)mentioning

confidence: 99%

Section: C2 Stratigraphy Of the Los Menucos Basin (Lmb)mentioning

confidence: 99%

The origin of Patagonia: insights from Permian to Middle Triassic magmatism of the North Patagonian Massif

et al. 2022

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“…It has been suggested that several Paleozoic and Mesozoic plant groups may have an Agathoxylon type of wood: seed ferns, cordaitaleans, and araucarian and cheirolepid conifers (Philippe et al, 2004; Taylor et al, 2009; Degani-Schmidt and Guerra-Sommer, 2016). Besides the fact that Glossopteridales and Cordaitales became extinct at the Permian–Triassic boundary (see Bodnar et al, 2021), the new species show dissimilarities with the wood anatomy of these Paleozoic lineages. According to Noll et al (2005), cordaitalean wood is characterized by predominant multiseriate tracheid radial pitting (with three to five pit series) and very subordinate uni- and biseriate pitting, in contrast to Agathoxylon argentinum n.…”

Section: Discussionmentioning

confidence: 94%

Araucariaceous fossil woods from the Upper Triassic Ischigualasto Formation (San Juan Province, Argentina): paleofloristic and paleoclimatic implications

et al. 2022

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In this contribution, fossil woods from the Valle de La Luna Member of the Upper Triassic Ischigualasto Formation at Ischigualasto Provincial Park, San Juan Province, Argentina, are described. The specimens are preserved as silica permineralization in tuffs intercalated with carbonaceous mudstone beds interpreted as distal floodplain facies. The fossil woods were assigned to the new species Agathoxylon argentinum since their anatomy differs from the known Mesozoic Gondwanan species of the genus Agathoxylon. The combination of characters present in the new taxon indicates an affiliation with the conifer family Araucariaceae. Signals of fungal-mediated wood decay were observed, comparable to the activity of basidiomycetes. Spherical structures attached to the walls of the tracheids were recognized and are interpreted as holocarpic chytrid fungi. The growth rings were quantitatively analyzed. Low values of percentage diminution, percentage latewood, and Ring Markedness Index, and a mean percentage skew of +11.5, were obtained, suggesting that the new species was an evergreen gymnosperm. The stratigraphic distribution and taxonomic composition of the Ischigualasto Formation fossil-plant-bearing levels were studied. A vegetation change is recorded in the fossil level bearing Agathoxylon argentinum n. sp., marked by the replacement of the corystosperm genera and a diminution of arboreal corystosperms. This floristic change, in addition to other evidence, indicates humid paleoclimatic conditions for the uppermost part of the Valle de La Luna Member of the Ischigualasto Formation.

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“…Grauvogel-Stamm and Ash (2005) suggested that these lycopsids were opportunistic pioneer plants and the Pleuromeia or lycopsid-dominated floras characterized the Induan-Olenekian in different regions of the world. In Argentina, the macrofloristic record or Pleuromeiales is never dominant or abundant (Bodnar et al 2021). The first diversification of the Umkomasiales (=Corystospermales) characteristic of the Triassic Dicroidium flora would have occurred during the Induan according to Bodnar et al (2021).…”

Section: Discussionmentioning

confidence: 99%

“…In Argentina, the macrofloristic record or Pleuromeiales is never dominant or abundant (Bodnar et al 2021). The first diversification of the Umkomasiales (=Corystospermales) characteristic of the Triassic Dicroidium flora would have occurred during the Induan according to Bodnar et al (2021). Remains of the Dicroidium flora occur intercalated between samples dated at 252 ± 2 Ma (Changhsingian–Induan) and 248 ± 2 Ma (Olenekian) in the Los Menucos Group in Patagonia (Luppo et al 2018; Falco et al 2020).…”

Section: Discussionmentioning

confidence: 99%

Age constraints of the Guttulapollenites hannonicus–Cladaitina veteadensis Biozone in Argentina reveal the first record of Early Triassic (Olenekian) palynofloras in Western Gondwana

et al. 2022

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The upper Palaeozoic basins of central-western Argentina include continuous fossiliferous successions spanning the Carboniferous-Permian interval. The palynostratigraphic biozones comprise Late Mississippian, Pennsylvanian and Cisuralian assemblages. Recently, new palynofloras of the La Veteada Formation were referred to the Lopingian (late Permian). However, they are characterized by spores and tetrads of Lundbladispora spp. and Densoisporites spp., pollen grains of Lunatisporites pellucidus, L. noviaulensis and Protohaploxypinus samoilovichii, and the alga Syndesmorion stellatum, that distinguish the post-Permian recovery floras worldwide. A new uranium-lead chemical abrasion-isotope dilution-thermal ionization mass spectrometry (U-Pb CA-ID-TIMS) age confirms the Olenekian age of this stratigraphic unit and allows the identification of the first Early Triassic palynofloras in this region of western Gondwana. Comparison and correlation with similar assemblages from the southern and northern hemispheres supports the Early Triassic turnover with an increase of lycopsid cavate spores associated with some diagnostic species of taeniate and non-taeniate bisaccate pollen.

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An updated scenario for the end-Permian crisis and the recovery of Triassic land flora in Argentina

Cited by 14 publications

References 89 publications

The origin of Patagonia: insights from Permian to Middle Triassic magmatism of the North Patagonian Massif

The origin of Patagonia: insights from Permian to Middle Triassic magmatism of the North Patagonian Massif

Araucariaceous fossil woods from the Upper Triassic Ischigualasto Formation (San Juan Province, Argentina): paleofloristic and paleoclimatic implications

Age constraints of the Guttulapollenites hannonicus–Cladaitina veteadensis Biozone in Argentina reveal the first record of Early Triassic (Olenekian) palynofloras in Western Gondwana

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