Big bedding planes: Outcrop size and spatial heterogeneity influence trace fossil analyses

Marenco, Katherine N.; Hagadorn, James W.

doi:10.1016/j.palaeo.2018.08.008

Cited by 19 publications

(16 citation statements)

References 84 publications

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“…timeenvironment matrix) meaningful in the case of simple ichnofabrics more accurate characterization of composite ichnofabrics because the different indexes consider not only burrow density, but the amount of burrow overlap and the sharpness of the original fabric commonly used in conjunction with analysis of tiering structure, evaluation of taphonomic filters, ichnoguild characterization, and ichnofabric constituent diagrams all metrics proposed based on a measurement of the percentage area bioturbated, but bioturbation should be measured as a unit volume per unit time estimations may be problematic if colonization surface is not located [19][20][21] bedding-plane bioturbation index (BP-BI) visual estimation of density of trace fossils on these horizontal surfaces with the aid of flashcards particularly suitable for the analysis of shallow-tier to superficial trace fossils preserved along lithological interfaces (e.g. most Ediacaran-Fortunian) important to assess synecological aspects of benthic faunas useful synergies if combined with methods developed to evaluate the degree of patchiness in horizontal distribution of trace fossils in strict sense not a real metric of degree of bioturbation, which typically implies disruption of the sedimentary fabric [22][23][24] (Continued. )…”

Section: The Link Between Trace Fossils Behaviour and Ecosystem Engineeringmentioning

confidence: 99%

The rise and early evolution of animals: where do we stand from a trace-fossil perspective?

Mángano

Buatois

2020

Interface Focus.

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The trace-fossil record provides a wealth of information to track the rise and early evolution of animals. It comprises the activity of both hard- and soft-bodied organisms, is continuous through the Ediacaran (635–539 Ma)– Cambrian (539–485 Ma) transition, yields insights into animal behaviour and their role as ecosystem engineers, and allows for a more refined characterization of palaeoenvironmental context. In order to unravel macroevolutionary signals from the trace-fossil record, a variety of approaches is available, including not only estimation of degree of bioturbation, but also analysis of ichnodiversity and ichnodisparity trajectories, and evaluation of the occupation of infaunal ecospace and styles of ecosystem engineering. Analysis of the trace-fossil record demonstrates the presence of motile benthic bilaterians in the Ediacaran, mostly feeding from biofilms. Although Ediacaran trace fossils are simple and emplaced at or immediately below the sediment surface, an increase in ichnofossil complexity, predation pressure, sediment disturbance and penetration depth is apparent during the terminal Ediacaran. Regardless of this increase, a dramatic rise in trace fossil diversity and disparity took place during the earliest Cambrian, underscoring that the novelty of the Fortunian (539–529 Ma) cannot be underestimated. The Fortunian still shows the persistence of an Ediacaran-style matground ecology, but is fundamentally characterized by the appearance of new trace-fossil architectural plans reflecting novel ways of interacting with the substrate. The appearance of Phanerozoic-style benthic ecosystems attests to an increased length and connectivity of the food web and improved efficiency in organic carbon transfer and nutrient recycling. A profound reorganization of the infaunal ecospace is recorded in both high-energy sand-dominated nearshore areas and low-energy mud-dominated offshore environments, during the early Cambrian, starting approximately during Cambrian Age 2 (529–521 Ma), but continuing during the rest of the early Cambrian. A model comprising four evolutionary phases is proposed to synthetize information from the Ediacaran–Cambrian trace-fossil record. The use of a rich ichnological toolbox; critical, systematic and comprehensive evaluation of the Ediacaran–Cambrian trace-fossil record; and high-resolution integration of the ichnological dataset and sedimentological information show that the advent of biogenic mixing was an important factor in fully marine environments at the dawn of the Phanerozoic.

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Section: The Link Between Trace Fossils Behaviour and Ecosystem Engineeringmentioning

confidence: 99%

The rise and early evolution of animals: where do we stand from a trace-fossil perspective?

Mángano

Buatois

2020

Interface Focus.

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“…These traits imply that, while the sedimentary environment in which the tidalite was deposited was clearly amenable to the tracemakers, burrowing was never pervasive everywhere. The vertical expression of intermittent burrowed laminae, colonized to their maximum possible extent, but separated by laminae that lack burrows, is explainable as a stratigraphic translation of an uneven spatial distribution of burrowed patches within the depositional environment (Miller & Smail, 1997; Dashtgard, 2011; Marenco & Hagadorn, 2019; Davies & Shillito, 2021). Supporting analogue comes from comparison with modern substrates dominantly colonized by vertically burrowing filter feeding organisms.…”

Section: Discussionmentioning

confidence: 99%

Non‐palimpsested crowded Skolithos ichnofabrics in a Carboniferous tidal rhythmite: Disentangling ecological signatures from the spatio‐temporal bias of outcrop

et al. 2021

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A heterolithic tidalite succession yielding spring–neap bundles is newly reported from a mid‐Carboniferous (Serpukhovian) section of the Alston Formation of Northumberland, England. The rhythmite records deposition over an interval that can be confidently calibrated to at least 84 lunar days, and attests to a non‐negligible tidal range in parts of the Northwest European Seaway in the late Mississippian. The tidalite is notable for the presence of a striking crowded Skolithos ichnofabric on both bedding planes and in vertical section. Bedding plane expressions of the ichnofabric reveal true substrates of sand piles excavated during burrow construction, in addition to an apparently remarkable equal spacing between individual burrows that is shown to be genuine through pair correlation function analysis. These characteristics show that the burrowed horizons were registered by contemporaneous ichnocoenoses, with no palimpsesting of burrows. The irregular vertical distribution of burrow horizons, despite a near‐continuous semi‐diurnal record of sedimentation, is suggested to be an artefact of spatial patchiness of burrowing communities in the depositional environment; imperfectly registered in a vertical profile with high‐temporal, low‐spatial resolution. The succession proves that burrow palimpsesting is not an inevitable ichnological conclusion of sedimentary stasis, and attests to intermittent palaeoecological fidelity of the stratigraphic record at the small spatio‐temporal scales recorded at outcrop.

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“…This variability could feasibly bias ichnological analysis (e.g. Marenco & Hagadorn, 2019) the significance of surficial trace fossils such as trackways is clearly apparent in extensive bedding planes of the gorges, but more likely to be concealed where bedding plane exposures are limited. Figure 12 shows how the exposure of trace fossils would be expected to vary within the different types of exposure, in scenarios of either ubiquitous or scattered presence of trace fossils.…”

Section: B the Role Of Outcrop Geomorphology In Analysis Of The Tumentioning

confidence: 99%

“…The extent of bioturbation varies from occasional overlapping traces to total destruction of any primary bedding. The degree of bioturbation likely reflects a spatial patchiness to burrowing intensity (Marenco & Hagadorn, 2019). On areas of the bedding surfaces where the burrows are sparse, surface features remain intact and the traces are often seen in association with subaqueous and emergent sedimentary surface features including wave ripple marks and adhesion marks.…”

mentioning

confidence: 99%

The Tumblagooda Sandstone revisited: exceptionally abundant trace fossils and geological outcrop provide a window onto Palaeozoic littoral habitats before invertebrate terrestrialization

Shillito

Davies

2020

Geol. Mag.

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The establishment of permanent animal communities on land was a defining event in the history of evolution, and one for which the ichnofauna and facies of the Tumblagooda Sandstone of Western Australia have been considered an archetypal case study. However, terrestrialization can only be understood from the rock record with conclusive sedimentological evidence for non-marine deposition, and original fieldwork on the formation shows that a marine influence was pervasive throughout all trace fossil-bearing strata. Four distinct facies associations are described, deposited in fluvial, tidal and estuarine settings. Here we explain the controversies surrounding the age and depositional environment of the Tumblagooda Sandstone, many of which have arisen due to the challenges in distinguishing marine from non-marine depositional settings in lower Palaeozoic successions. We clarify the terminological inconsistency that has hindered such determination, and demonstrate how palaeoenvironmental explanations can be expanded out from unambiguously indicative sedimentary structures. The Tumblagooda Sandstone provides a unique insight into an early Palaeozoic ichnofauna that was strongly partitioned by patchy resource distribution in a littoral setting. The influence of outcrop style and quality is accounted for to contextualize this ichnofauna, revealing six distinct low-disparity groups of trace fossil associations, each related to a different sub-environment within the high-ichnodisparity broad depositional setting. The formation is compared with contemporaneous ichnofaunas to examine its continued significance to understanding the terrestrialization process. Despite not recording permanent non-marine communities, the Tumblagooda Sandstone provides a detailed picture of the realm left behind by the first invertebrate pioneers of terrestrialization.

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Big bedding planes: Outcrop size and spatial heterogeneity influence trace fossil analyses

Cited by 19 publications

References 84 publications

The rise and early evolution of animals: where do we stand from a trace-fossil perspective?

The rise and early evolution of animals: where do we stand from a trace-fossil perspective?

Non‐palimpsested crowded Skolithos ichnofabrics in a Carboniferous tidal rhythmite: Disentangling ecological signatures from the spatio‐temporal bias of outcrop

The Tumblagooda Sandstone revisited: exceptionally abundant trace fossils and geological outcrop provide a window onto Palaeozoic littoral habitats before invertebrate terrestrialization

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