The Ediacaran–Cambrian boundary: Evaluating stratigraphic completeness and the Great Unconformity

Shahkarami, Setareh; Buatois, Luís A.; Mángano, M. Gabriela; Hagadorn, James W.; Almond, John E.

doi:10.1016/j.precamres.2020.105721

Cited by 39 publications

(14 citation statements)

References 178 publications

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“…3A, 4A, 6C,D), perhaps indicating a regression-based influence on both preserved rock volume and available habitable ecospace or associated environmental shifts that result in a decrease in the extent and abundance of shelf life. Alternatively, it could reflect a facies-control on sampling bias or destruction of terminal Ediacaran sediment cover during extensive Cambrian transgression (Peters and Gaines, 2012;Shahkarami et al, 2020). More 18/34 detailed data on assemblage-level biodiversity (similar to Cohen and Macdonald, 2015, but with higher resolution for the Ediacaran) and more detailed stratigraphic and environmental context for those fossils and the surrounding unfossiliferous successions will yield further insight into the common cause hypothesis, which finds some support in the convergence of quantitative stratigraphic, geochemical, and biological patterns documented here (Fig.…”

Section: The Shuram-wonoka Anomaly and Marine Transgressionmentioning

confidence: 99%

“…Great strides have been made in understanding the Ediacaran and its critical transition with the Phanerozoic. Sequence stratigraphy has served as an important interpretive framework in this regard by environmentally contextualizing and facilitating the correlation of vari-ous proxy records Van Wagoner et al, 1988;Le Guerroué et al, 2006;Jiang et al, 2011;Macdonald et al, 2013;Smith et al, 2016a;Xiao et al, 2016;Shahkarami et al, 2020;Xiao and Narbonne, 2020). Although interpretations of proxies are always subject to revision and refinement, all of the substantive data used for understanding the Earth system are anchored by their physical positions within the rock record itself.…”

Section: Introductionmentioning

confidence: 99%

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Macrostratigraphy of the Ediacaran System in North America

Segessenman¹,

Peters²

2023

Preprint

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Ediacaran sediments record the termination of Cryogenian ‘Snowball Earth’ glaciations, preserve the first occurrences of macroscopic metazoans, and contain one of the largest known negative δ13C excursions (the Shuram-Wonoka). The rock record for the transition between the Proterozoic and Phanerozoic in North America is also physically distinct, with much of the continent characterized by a wide variety of mostly crystalline Proterozoic and Archean rocks overlain by early Paleozoic shallow marine sediments. Here, we present quantitative macrostratigraphic summaries of rock quantity and type using a new comprehensive compilation of Ediacaran geological successions in North America. In keeping with previous results that have identified early Paleozoic burial of the ‘Great Unconformity’ as a major transition in the rock record, we find that the Ediacaran System has greatly reduced areal extent and volume in comparison to the Cambrian and most younger Phanerozoic systems. The closest quantitative analogue to the Ediacaran System in North America is the Permian-Triassic interval, deposited during the culminating assembly and early rifting phases of the supercontinent Pangea. The Shuram-Wonoka carbon isotope excursion occurs against the backdrop of the largest increase in carbonate and total rock volume observed in the Ediacaran. The putatively global Gaskiers glaciation (~580-579 Ma), by contrast, has little quantitative expression in these data. Although the importance of Ediacaran time is often framed in the context of glaciation, biological evolution, and geochemical perturbations, the quantitative expressions of rock area, volume, and lithology in the geologic record clearly demarks the late Ediacaran to early Cambrian as the most dramatic transition in at least the past 635 Myr. The extent to which the timing and nature of this transition is reflected globally remains to be determined, but we hypothesize that the large expansion in the extent and volume of sedimentation within the Ediacaran, particularly among carbonates, and again from the Ediacaran to the Cambrian, documented here over approximately 17% of Earth’s present-day continental area, provides important insights into the drivers of biogeochemical and biological evolution at the dawn of animal life.

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Section: The Shuram-wonoka Anomaly and Marine Transgressionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Macrostratigraphy of the Ediacaran System in North America

Segessenman¹,

Peters²

2023

Preprint

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“…Although not definitive, the implication is increasing levels of microbe-animal communication, with these molecules being potential semiochemical messengers for communication between the enclosed intestinal microbiome and the vertebrate animal. Potentially defined as a major evolutionary transition [69], it is possible that this development allowed early animals to transition across the Ediacaran-Cambrian boundary [70].…”

Section: Semiochemicals: From Single Cells To Multicellular Animalsmentioning

confidence: 99%

The Enclosed Intestinal Microbiome: Semiochemical Signals from the Precambrian and Their Disruption by Heavy Metal Pollution

Smith¹,

Palacios-Pérez

Jheeta³

2022

Life

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It is increasingly likely that many non-communicable diseases of humans and associated animals are due to the degradation of their intestinal microbiomes, a situation often referred to as dysbiosis. An analysis of the resultant diseases offers an opportunity to probe the function of these microbial partners of multicellular animals. In our view, it now seems likely that vertebrate animals and their microbiomes have coevolved throughout the Ediacaran–Cambrian transition and beyond, operating by semiochemical messaging between the multicellular host and its microbial community guest. A consideration of the overall role of the mutualistic intestinal microbiome as an enclosed bioreactor throws up a variety of challenging concepts. In particular: the significance of the microbiome with respect to the immune system suggests that microeukaryotes could act as microbial sentinel cells; the ubiquity of bacteriophage viruses implies the rapid turnover of microbial composition by a viral-shunt mechanism; and high microbial diversity is needed to ensure that horizontal gene transfer allows valuable genetic functions to be expressed. We have previously postulated that microbes of sufficient diversity must be transferred from mother to infant by seemingly accidental contamination during the process of natural birth. We termed this maternal microbial inheritance and suggested that it operates alongside parental genetic inheritance to modify gene expression. In this way, the adjustment of the neonate immune system by the microbiome may represent one of the ways in which the genome of a vertebrate animal interacts with its microbial environment. The absence of such critical functions in the neonate may help to explain the observation of persistent immune-system problems in affected adults. Equally, granted that the survival of the guest microbiome depends on the viability of its host, one function of microbiome-generated semiochemicals could be to facilitate the movement of food through the digestive tract, effectively partitioning nutrition between host and guest. In the event of famine, downregulation of microbial growth and therefore of semiochemical production would allow all available food to be consumed by the host. Although it is often thought that non-communicable diseases, such as type 2 diabetes, are caused by consumption of food containing insufficient dietary fibre, our hypothesis suggests that poor-quality food is not the prime cause but that the tendency for disease follows the degradation of the intestinal microbiome, when fat build-up occurs because the relevant semiochemicals can no longer be produced. It is the purpose of this paper to highlight the possibility that the origins of the microbiome lie in the Precambrian and that the disconnection of body and microbiome gives rise to non-communicable disease through the loss of semiochemical signalling. We further surmise that this disconnect has been largely brought about by heavy metal poisoning, potentially illuminating a facet of the exposome, the sum total of environmental insults that influence the expression of the genetic inheritance of an animal.

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“…While recent studies showed that this unconformity was formed by the composite regional tectonism and the global eustasy before the Neoproterozoic snowball earth (Flowers et al, 2020;Shahkarami et al, 2020). In addition, the Great Unconformity between the Precambrian basement and Cambrian sedimentary cover, particularly in Laurentia with extensive documentation, was closely related with the dramatic change of the surface and deep geodynamic process during the Proterozoic to the Phanerozoic (Allen & Campbell, 2008;Meert & Lieberman, 2008;Olierook et al, 2019;Squire, Campbell, Allen, & Wilson, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…C. He et al, 2016;M. Li, Vandyk, et al, 2020;Shahkarami, Buatois, Mángano, Hagadorn, & Almond, 2020;B. Wan et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Geochronological constraints of the Huoshan Formation in the Lüliang area: Implication on the Great Unconformity in the central North China Craton

2021

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The Great Unconformity between the Precambrian basement and the Phanerozoic successions marks a major gap in the stratigraphic records globally. However, previous studies on the time, magnitude, and the spatial distribution of this unconformity in the North China Craton (NCC) mainly focused on the south‐eastern margin and were seldom investigated in the central area. In this study, we report detrital zircon geochronological data of the Huoshan Formation, a siliciclastic stratigraphic unit between the Archean‐Palaeoproterozoic metamorphic basement and Cambrian successions in the central NCC. The youngest age peak of 685 Ma suggests that the Huoshan Formation was formed in the post‐Ediacaran rather than the counterpart of the lower Palaeo‐Mesoproterozoic Changcheng Group. The detrital zircons of the quartz sandstone from the Huoshan Formation show varied age populations of 2,700–2,600 Ma, 2,600–2,500 Ma, 2,200–2,000 Ma, 1,900–1,800 Ma, and 700–600 Ma, which correspond to typical tectono‐thermal events of the NCC. First, the widely developed Precambrian tectono‐thermal events in the NCC were archived in the detrital zircons in the Huoshan Formation, for instance, the crustal growth event at 2,600–2,500 Ma and the 1,850–1,800 Ma magmatic and metamorphic events. Second, the age peaks younger than 1,000 Ma are not distinct in the NCC and are possibly from other terranes. The Great Unconformity represented by the boundary between the Huoshan Formation and the underlying Archean‐Palaeoproterozoic basement suggested a high topography and long‐term denudation in the Lüliang area during the transition from the Proterozoic to the Phanerozoic.

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The Ediacaran–Cambrian boundary: Evaluating stratigraphic completeness and the Great Unconformity

Cited by 39 publications

References 178 publications

Macrostratigraphy of the Ediacaran System in North America

Macrostratigraphy of the Ediacaran System in North America

The Enclosed Intestinal Microbiome: Semiochemical Signals from the Precambrian and Their Disruption by Heavy Metal Pollution

Geochronological constraints of the Huoshan Formation in the Lüliang area: Implication on the Great Unconformity in the central North China Craton

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