The occurrence of <em>Dickinsonia</em> in non-marine facies

Abstract

En los Urales centrales, Dickinsonia se encuentra en medios de transición entre sustratos continentales y marinos marginales, generalmente de tipo laguna costera rodeada por llanuras mareales. Otro aspecto llamatico es la ausencia de otros taxones ediacáricos asociados con Dickinsonia, relativamente abundantes en otros medios. De hecho, el Miembro de Sinii Kamen de la Formación de Cherny Kamen ha librado una asociación de macrofósiles ediacáricos, que incluye anclajes de tipo aspidellamorfo y mawsonitomorfo, frondomorfos, palaeopascichnidos y estructuras en anillos concéntricos de origen microbiano, con los que no se asocia Dickinsonia.

The influence of environmental setting on the community ecology of Ediacaran organisms

“…Only taxa that had sufficient abundance (greater than five specimens) for spatial analyses were used in this study, and these were grouped within one of six taxonomic groups: Aspidella, Dickinsonia, Funisia, Kimberella, Orbisiana and the trace fossil Kimberichnus. Aspidella is considered a form taxon here, in line with previous studies [65,75], and may represent multiple different types of organism, such as the holdfasts of frondose taxa. We also note that on FUN4 and FUN5, Funisia fossils are represented only by their holdfast 'buds', rather than by the complete Funisia tubular organism [76].…”

“…Surface DS is a Dickinsonia-bearing surface (figure 1b) from the Konovalovka Member of the Cherny Kamen Formation, cropping out along the Sylvitsa River, Central Urals, Russian Federation [63,64]. It lies within an interval of finely alternating wave-rippled sandstones, siltstones and mudstones that are sandwiched between two thick intervals of biolaminated sandstone characterized by microbial shrinkage cracks and salt crystal pseudomorphs [65]. The overall succession is considered transitional from marginal marine to non-marine, with the fossil-bearing interval interpreted as having been deposited in a lagoon within a tidal flat depositional system [65].…”

“…It lies within an interval of finely alternating wave-rippled sandstones, siltstones and mudstones that are sandwiched between two thick intervals of biolaminated sandstone characterized by microbial shrinkage cracks and salt crystal pseudomorphs [65]. The overall succession is considered transitional from marginal marine to non-marine, with the fossil-bearing interval interpreted as having been deposited in a lagoon within a tidal flat depositional system [65]. A U/Pb zircon date of 557 ± 13 Ma from volcanic tuffs near the base of the Cherny Kamen Formation [64] suggests that this unit may royalsocietypublishing.org/journal/rsfs Interface Focus 10: 20190109…”

Ecología de <em>Dickinsonia</em> en llanuras mareales

“…Most important, nine square meters of the surfaces preserved over a hundred of exquisitely preserved Dickinsonia specimens in life association. The sedimentary environment of this fossil assemblage has been reconstructed as a restricted coastal lagoon surrounded by tidal flats (Bobkov et al, 2019), which seems very unusual compared to other fossil localities conventionally regarded as representing shallow marine settings.…”

Ediacaran life close to land: Coastal and shoreface habitats of the Ediacaran macrobiota, the Central Flinders Ranges, South Australia

“…Whereas the studied Ediacara Member estuarine deposits (Facies 1 and 3) are devoid of macrobiota (but also only scarcely contain true substrates on which macrobiota would have a chance of becoming preserved), mixed-flat and lagoonal facies are not. Whilst Ediacaran macrobiota have recently been suggested to be preserved in tidal-flat facies elsewhere (Bobkov et al 2019;Sozonov et al 2019), the likely brackish-water conditions of these settings would not necessarily be expected to favor long-term survival of such organisms, given their typical inferred marine habitats, and such reports demand further investigation.…”