Ichnology of Marginal Marine Facies of the Agrio Formation (Lower Cretaceous, Neuquén Basin, Argentina) at its Type Locality

Fernández, Diana Elizabeth; Pazos, Pablo J.

doi:10.5710/amgh.23.7.2012.439

Cited by 25 publications

(12 citation statements)

References 68 publications

(79 reference statements)

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“…Palaeophycus is considered a dwelling or feeding structure of mobile, suspensivorous or predatory wormlike-organism, such as annelids (Fernández & Pazos, 2012). It is a eurybenthic facies-crossing form produced probably by polychaetes or annelids (Pemberton & Frey, 1982) and it occurs few centimeters below the sediment-water interface, suggesting an unconsolidated substrate, in relatively moderate to low energy shorface/offshore conditions (Tiwari et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Based on the regularly ovoidal uniformly distributed pellets, it can be placed under Ophiomorpha nodosa. As no branching was observed in the specimen, it cannot be considered as a burrow system (Fernández & Pazos, 2012). These traces may have been burrow systems, but are only partially preserved by erosion or lateral variation.…”

Section: Ophiomorpha Lundgren 1891mentioning

confidence: 92%

“…Furthermore, it has been pointed out that S. verticalis is distinguished from S. linearis and S. magnus because these last two ichnospecies show a great diameter (3-7 mm and 6-12 mm, respectively) (Alpert, 1974;Fernández & Pazos, 2012). Besides having a large diameter, Skolithos ingens and S. annulatus have characteristically ornamented walls (protuberances in S. ingens and annulations in S. annulatus), which are absent in S. verticalis (Fernández & Pazos, 2012). The characteristics of this trace, such as its verticality, cylindrical form, and smooth walls, are similar to those reported by Lech et al (2000) as the typical trace of S. linearis.…”

Section: Skolithos Haldeman 1840mentioning

confidence: 99%

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Marginal marine trace fossils from the Cárdenas Formation (Maastrichtian), Rayón municipality, San Luis Potosí, Central Mexico

Palma-Ramírez¹,

Maldonado-Sarabia²,

Stimson³

2019

Rev. bras. paleontol.

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The State of San Luis Potosí, Mexico, is rich in fossils and has a long-standing tradition of paleontological research. Nevertheless, most of these studies have been focused on vertebrates and invertebrates body fossils, with the ichnological record being overlooked. Here, we report the occurrence of ichnofossils (Diplocraterion parallelum, Ophiomorpha nodosa, Skolithos linearis, and Palaeophycus tubularis) from the Upper Cretaceous (Maastrichtian) Cárdenas Formation, southeastern San Luis Potosí. Invertebrate trace fossils and associated body fossils suggest that the Cárdenas Formation was deposited in a low to high energy system, with occasional storm events, in a shallow water platform (delta plain or coastal paleoenvironment influenced by tidal action).

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Section: Discussionmentioning

confidence: 99%

Section: Ophiomorpha Lundgren 1891mentioning

confidence: 92%

Section: Skolithos Haldeman 1840mentioning

confidence: 99%

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Marginal marine trace fossils from the Cárdenas Formation (Maastrichtian), Rayón municipality, San Luis Potosí, Central Mexico

Palma-Ramírez¹,

Maldonado-Sarabia²,

Stimson³

2019

Rev. bras. paleontol.

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“…The upper member, or Agua de la Mula Member (Leanza et al, 2001), of the Agrio Formation is late Hauterivian to early Barremian in age (Aguirre-Urreta et al, 2007Aguirre-Urreta and Rawson, 2012). It comprises mixed carbonate-siliciclastic marine and marginal-marine deposits (Spalletti et al, 2001a;Lazo et al, 2005;Pazos and Fernández, 2010;Fernández and Pazos, 2012). The uppermost part of the unit was tidally influenced (Pazos et al, 2012;Fernández and Pazos, 2013), while the lowermost levels have been interpreted as an open marine ramp under fluctuating rates of siliciclastic input and carbonate productivity (Spalletti et al, 2001b;Comerio et al, 2018).…”

Section: Geological Setting Study Area and Paleoenvironmental Contextmentioning

confidence: 99%

Brittle stars from the Lower Cretaceous of Patagonia: first ophiuroid articulated remains for the Mesozoic of South America

Fernández

Giachetti

Stöhr

et al. 2019

andgeo

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The first articulated remains of ophiuroids for the Mesozoic of South America are described from the Lower Cretaceous of Neuquén Basin, Argentina. The taxonomic analysis allows the assignment of the material described herein to the extinct genus Ophiopetra. The specimens belong to a new species, but considering the poor preservation, a new name is not introduced, as it would be based on an incomplete diagnosis. Certain characteristics (e.g., the diameter of the disc, the width/height ratio of the vertebrae) suggest that these ophiuroids are paedomorphic specimens. In light of the latest classification of the Ophiuroidea, and new insights on the spine articulation microstructure of Ophiopetra lithographica presented herein, a transfer of Ophiopetra to the family Ophionereididae within the order Amphilepidida is proposed. This material expands the palaeogeographic record of this genus, since it represents the first remains of Ophiopetra described in the Southern Hemisphere. It is also the first Cretaceous record of the genus worldwide.

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“…5.14e); em vista destas características, estas zooturbações foram atribuídas ao icnogênero Thalassinoides (cf. elementos diagnósticos descritos emFernández & Pazos 2012). Estruturas de sobrecarga (flame) podem ocorrer no topo.…”

unclassified

Eolianitos Quaternários do Nordeste do Brasil

Arias¹

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The coast of Northeast Brazil is under the influence of the winds that blow towards the Intertropical Convergence Zone (ITCZ) and that have favored the formation of eolian depositional systems in the late Quaternary. In areas with bioclastic contribution, such as Piauí and part of Ceará and Rio Grande do Norte, on the coast of the continental portion, and the Fernando de Noronha Archipelago, in the insular portion, these systems include eolianites, which were characterized here as for: paleowinds, depositional facies, granulometry, petrography, SEM, carbonate content, heavy minerals and chronology via 14 C and OSL. The continental eolianites are associated with an inner shelf in mixed ramp, with a smooth inclination (<1°), which extends in the emerged area, generating large space for eolian accumulation, and favors the development of deflation plains with kilometers of extension; the outcrops are extensive, a few meters thick, dominated by facies with low angle cross stratifications, attributed mainly to trailing ridges. Island eolianites are associated with a narrow isolated carbonate shelf (less than 10 km), with reef edges and sharp slopes; because the islands are supported by volcanic-pyroclastic rocks of Quaternary age, with rugged relief, the area of eolian accumulation is limited, which means that the outcrops are less extensive and of greater thickness, with predominance of high angle cross stratifications, sometimes with preservation of bedform crests. Continental and island eolianites have in common the presence of red algae as the dominant intraclast grain and of early calcitic cement, formed in meteoric vadose conditions in Holocene deposits and phreatic conditions in the Pleistocene ones. Mainly in Pleistocene eolianites, inversions of 14 C ages between bioclast and cement, associated with the presence of bioclast pseudomorphs formed by moldic filling, indicate that the diagenetic history had at least three phases: early interparticle micritic cementation, under conditions of relative aridity; moldic dissolution in the phase of increase and/or peak of humidity; and filling of pores with spar or microspar at the beginning of the new cycle of falling humidity. Among continental eolianites, ages vary between 7.0 ka and 14 years, in less consolidated outcrops, with a preserved ridge shape; and between 86.2 to 40.7 ka, compatible with MIS 5 and MIS 3, in the strongly consolidated outcrops, which occur on coastal cliffs. In insular eolianites, two 14 C age ranges were found (between 46.1 and 21.7 ka cal AP and from 18.7 to 5.3 ka cal AP), the first of them containing bioclasts without age inversion with the cement, which allows suggesting deposition in the MIS 3 event.

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Ichnology of Marginal Marine Facies of the Agrio Formation (Lower Cretaceous, Neuquén Basin, Argentina) at its Type Locality

Cited by 25 publications

References 68 publications

Marginal marine trace fossils from the Cárdenas Formation (Maastrichtian), Rayón municipality, San Luis Potosí, Central Mexico

Marginal marine trace fossils from the Cárdenas Formation (Maastrichtian), Rayón municipality, San Luis Potosí, Central Mexico

Brittle stars from the Lower Cretaceous of Patagonia: first ophiuroid articulated remains for the Mesozoic of South America

Eolianitos Quaternários do Nordeste do Brasil

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