Ordovician and Silurian trace fossils from Northern Benin (W-Africa)

Seilacher, Adolf; Alidou, S.

doi:10.1127/njgpm/1988/1988/431

Cited by 18 publications

(10 citation statements)

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“…Compilation of ichnological data was a major part of the work of A. Seilacher and P. Crimes. Seilacher (1974, 1977, 1986) focused on the variety of graphoglyptid trace fossils from the deep sea (i.e. patterned trace fossils forming nets, regular meanders and spirals), aiming to understand their environmental adaptation through time (e.g.…”

Section: Introductionmentioning

confidence: 99%

New insights into the early evolution of horizontal spiral trace fossils and the age of the Brioverian series (Ediacaran–Cambrian) in Brittany, NW France

et al. 2021

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In northwestern France, the Brioverian series is a thick siliciclastic succession deposited during the Cadomian cycle (c. 750–540 Ma). In the uppermost Brioverian beds, previous studies unravelled an assemblage dominated by simple horizontal trace fossils associated with microbially stabilized surfaces. Here, we report Spirodesmos trace fossils – one-way, irregular and regular horizontal spirals – from Crozon (Finistère, Brittany), Montfort-sur-Meu and St-Gonlay (Ille-et-Vilaine, Brittany). After reviewing the literature on horizontal spiral trace fossils, an Ediacaran–Fortunian Spirodesmos pool is identified from marginal-marine to shelf settings, while an Ordovician–Recent trend formed in the deep-marine realm. These results suggest that an onshore–offshore migration in Spirodesmos took place during Ediacaran–Fortunian to Ordovician time, similar to what happened in graphoglyptids. In addition, the age of the uppermost Brioverian beds (Ediacaran or early Cambrian) is still a pending question. Here, we report two new U–Pb detrital zircon datings from sandstone samples in St-Gonlay, giving maximum deposition ages of 551 ± 7 Ma and 540 ± 5 Ma. Although these results do not discard an Ediacaran age for the uppermost Brioverian beds, a Fortunian age is envisioned because the new dating corroborates previous dating from Brittany, Mayenne and Normandy. However, the intervals of error of the radiometric dating, and the dominance of non-penetrative trace fossils associated with matgrounds (an ecology more typical of the Ediacaran Period), do not allow definitive conclusions on the age of the uppermost Brioverian beds.

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Section: Introductionmentioning

confidence: 99%

New insights into the early evolution of horizontal spiral trace fossils and the age of the Brioverian series (Ediacaran–Cambrian) in Brittany, NW France

et al. 2021

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“…Examining the role of these various currents, thus, is crucial, especially when viewed from ethological (characteristic behaviour of producers) and colonization style perspectives (Orr, 2001). As a whole, the recognized trace‐fossil assemblages in the Ghelli Formation are indicative of the Nereites ichnofacies, encompassing the Ophiomorpha rudis , Paleodictyon and Nereites subichnofacies (Seilacher, 1974; Uchman, 2001, 2007). The Ophiomorpha rudis subichnofacies occurs in thick‐bedded channel and proximal lobe‐related environments, the Paleodictyon subichnofacies in thin‐bedded fan fringe, channel margin and levée overbank and lobe fringe environments, and the Nereites subichnofacies in mud‐rich fan fringe or distal lobe–basin floor environments (Uchman, 2001, 2004; Heard & Pickering, 2008; Knaust, 2009; Uchman, 2009; Monaco et al ., 2010; Rodrìguez‐Tovar et al ., 2010; Cummings & Hodgson, 2011; Phillips et al ., 2011; Callow et al ., 2013, 2014; Heard et al ., 2014; Knaust et al ., 2014; Bayet‐Goll et al ., 2014, 2016).…”

Section: Discussionmentioning

confidence: 99%

The influence of hybrid sediment gravity flows on distribution and composition of trace‐fossil assemblages: Ordovician succession of the north‐eastern Alborz Range of Iran

et al. 2022

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The distribution of conventional subichnofacies in deep‐water fan systems (i.e. Ophiomorpha rudis–Paleodictyon–Nereites‐subichnofacies) depends on the presence of fully turbulent non‐cohesive flows such as low‐density turbidites and high‐density turbidites. However, changes in flow state between laminar and turbulent conditions can affect the distribution style of conventional subichnofacies. This study deals with the effects of environmental or ecological stressors as a result of hybrid sediment gravity flows (hybrid event beds) on distribution and composition of trace fossils in the deep‐marine depositional system of the Ordovician Ghelli Formation in the north‐eastern Alborz Range. The spatial distribution and sedimentological character of hybrid sediment gravity flows, in particular their abundance in the down‐dip parts of lobe‐related facies associations, are interpreted as products of longitudinal and lateral transformation from turbidity currents to debris flows promoted by incorporation of significant claystone and mudstone clasts into the flow by seafloor erosion and flow bulking. Seven trace‐fossil assemblages were recognized in the channel and lobe‐related facies associations. The observed spatial distribution of trace‐fossil assemblages in the interpreted frontal and lateral lobe fringes, somewhat contrasts with conventional subichnofacies distribution models. The development of cohesive flows and rapid emplacement of turbidite, banded and debrite beds could be accompanied by fluctuations in physico‐chemical conditions and, hence, the time available for colonization and the lifestyle of producers. This study suggests that, compared to the archetypal models of the subichnofacies in down‐dip parts of lobe‐related facies associations, ichnodiversity and density of bioturbation are drastically reduced, and trace fossils are limited to simple, shallow‐tier feeding strategies. Commonly, the presence of cohesive flows may have forced the producers in the Paleodictyon and Nereites‐subichnofacies to migrate into lateral lobe fringe with more participation of low‐density turbidites. This study shows that, in addition to sedimentological and architectural criteria, ichnological criteria can also be used to distinguish between frontal and lateral lobe‐fringe deposits in unconfined systems.

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“…In contrast, the limid bivalve Plagiostoma gigantea was stationary, living as an epibenthic, orthothetic edgewise recliner sensu Seilacher (1984), whereby both valves served as a substrate for Rodocanalis . A range of epibionts is documented from a Triassic congener, Plagiostoma striata (Seilacher 1954). Similar to the hydroids involved in Rodocanalis , these taxa are not specifically adapted to Plagiostoma .…”

Section: Submarines and Islands: Ecologies Of The Molluscan Hostsmentioning

confidence: 99%

Putative hydroid symbionts recorded by bioclaustrations in fossil molluscan shells: a revision and reinterpretation of the cecidogenusRodocanalis

Wisshak

Schneider²,

Mikuláš

et al. 2023

Papers in Palaeontology

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The fossil record yields a peculiar phenomenon in different kinds of molluscan shells: bioclaustrations formed around (epi)symbionts during growth of the hosts' shell margin. Four morphologies, two of them formerly considered bioerosion traces, are here united in the parataxonomy of bioclaustration structures under the revised cecidogenus Rodocanalis. These are: (1) simple linear grooves (Rodocanalis linearis csp. nov.) formed below the periostracum in Pleistocene to Recent endobenthic bivalves;(2) series of distally ramifying grooves (Rodocanalis runicus) in Silurian orthoconic nautiloids; (3) irregular networks of grooves (Rodocanalis reticulatus) in Jurassic to Cretaceous bivalves and gastropods; and (4) regular reticulate networks (Rodocanalis geometricus csp. nov.) in Jurassic to Cretaceous gastropods. The linear grooves might be associated with commensal worms, while multiple lines of reasoning point towards hydrozoan symbionts in the case of the

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Ordovician and Silurian trace fossils from Northern Benin (W-Africa)

Cited by 18 publications

References 0 publications

New insights into the early evolution of horizontal spiral trace fossils and the age of the Brioverian series (Ediacaran–Cambrian) in Brittany, NW France

New insights into the early evolution of horizontal spiral trace fossils and the age of the Brioverian series (Ediacaran–Cambrian) in Brittany, NW France

The influence of hybrid sediment gravity flows on distribution and composition of trace‐fossil assemblages: Ordovician succession of the north‐eastern Alborz Range of Iran

Putative hydroid symbionts recorded by bioclaustrations in fossil molluscan shells: a revision and reinterpretation of the cecidogenusRodocanalis

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