Ordovician and Silurian Formations of Anticosti Island, Quebec

Bolton, T E

doi:10.4095/101165

Cited by 30 publications

(20 citation statements)

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“…This raises questions about the possibility of an adjustment of the O-S boundary at least 30 m above the base of the Becscie Formation. It is interesting to note that earlier stratigraphic studies (Twenhofel 1928;Bolton 1961) have also placed the Ellis Bay-Becscie contact at a comparable stratigraphic level. A high-resolution δ 13 C curve for the Rhuddanian strata of Anticosti Island is, however, required to reevaluate the position of the O-S boundary on Anticosti Island.…”

Section: Mirnymentioning

confidence: 97%

A high-resolution, continuous δ¹³C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

Mauviel

Desrochers

2016

Can. J. Earth Sci.

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One of the best-exposed and most complete stratigraphic records from paleotropical areas spanning the Ordovician-Silurian (O-S) boundary is located on Anticosti Island, eastern Canada. Our study is the first one to sample strata superbly exposed at low tide along the west coast of Anticosti Island, thus providing a previously unexploited, nearly complete stratigraphic interval (~300 m) at the O-S boundary for δ 13 C chemostratigraphy. A new high-resolution δ 13 C curve with more than 500 data points spaced at every ~0.5 m has been produced rectifying important pitfalls of previously published δ 13 C curves (i.e. low sampling resolution, variable sampling intervals, stratigraphic gaps). This new highresolution δ 13 C curve displays a lower and an upper positive Hirnantian Isotope Carbon Excursions (HICE) recognized elsewhere around the globe. The ascending limb of the lower HICE excursion starting from baseline values of +0.5‰ corresponds to the upper 20 m of the late Katian Vauréal Formation, but δ 13 C peak values of +2.5‰ occur in the lower part of the Hirnantian Ellis Bay Formation. In spite of a δ 13 C record segmented by a few stratigraphic hiatuses, the upper HICE excursion, with its peak values of +4.5‰, is well recorded in the upper part of the Hirnantian Ellis Bay Formation. When compared to sections from around the globe, our δ 13 C curve displays a distinct long-term trend with a long sustained lower HICE excursion followed abruptly by the upper HICE excursion and return to baseline values of +0.5‰ prior to the Rhuddanian. The continued descending isotopic trend well into the Becscie Formation suggests that the O-S boundary may occur at a higher stratigraphic level (up to 30 m) than previously interpreted. Active subsidence combined with moderate initial water depths prior to the Hirnantian were key Page 2 of 24 Can. J. Earth Sci. Downloaded from www.nrcresearchpress.com by University of Otago on 03/28/16 For personal use only. This Just-IN manuscript is the accepted manuscript prior to copy editing and page composition. It may differ from the final official version of record.3 factors controlling the deposition of a thick O-S sedimentary succession with a few hiatuses on Anticosti Island and capturing a comprehensive, reliable δ 13 C record across this interval.

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Section: Mirnymentioning

confidence: 97%

A high-resolution, continuous δ¹³C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

Mauviel

Desrochers

2016

Can. J. Earth Sci.

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“…Rhegmaphyllum appeared immediately above the Ellis Bay Formation, in basal beds of the Becscie Formation that are thought to be latest Ordovician (Elias 1989;McAuley & Elias 1990). A more diverse coral fauna of distinctly Silurian aspect, including genera such as the solitary rugosans Cyathactis and Dinophyllum, occurs higher in the Becscie, in strata of Early Silurian (Early Llandovery, Rhuddanian) age (Bolton 1981;Elias 1989). …”

Section: Structurementioning

confidence: 98%

Chapter 9 Coral biogeography in the Late Ordovician (Cincinnatian) of Laurentia

Elias

Young²,

Lee

et al. 2013

Memoirs

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During the Late Ordovician, Cincinnatian, the epicontinental seas and continental margin of Laurentia provided habitats that were suitable for corals. Biogeographical differentiation occurred within this equatorially placed continent, when corals were introduced to areas that had fundamentally different environments. There were four biogeographical divisions, characterized by distinctive faunas that included some endemic taxa: the Red River–Stony Mountain Province, Richmond Province, Edgewood Province and the less well understood, informal ‘Continental Margin’ Area. In each division, the potential for diversification and the capacity for diversity were determined by factors such as the duration and size of the division, the amount of immigration, the extent of evolution and biogeographical differentiation, faunal responses to changes in sea-level and climate, and the complexity of the ecological structure. The development of multiple biogeographical divisions, each contributing to overall diversity, enhanced the ‘Great Ordovician Biodiversification Event’. During the latest Ordovician mass extinction, there was a reduction of diversity and loss of biogeographical divisions within Laurentia. The divisions were terminated when their characteristic taxa disappeared, in response to major environmental changes associated with glaciation in Gondwana and subsequent global warming.

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“…Billings (1862, 1865, 1866) and Twenhofel (1928) described various species of Favosites from Anticosti Island, and provided some information on their stratigraphic distributions and faunal associations. Bolton (1981) also illustrated some specimens from various Ordovician and Silurian formations of that island. Twenhofel (1928, p. 127) assigned the specimens that contain the spicules to the species Favosites forbesi Milne‐Edwards and Haime, 1855.…”

Section: Anticosti Islandmentioning

confidence: 99%

Spicules in Silurian Tabulate Corals From Canada, and Implications for Their Affinities

Chatterton¹,

Copper²,

Dixon³

et al. 2008

Palaeontology

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Specimens of Favosites from upper Llandovery strata of Anticosti Island show three types of calcite structures, herein interpreted as spicules, preserved within their calices and on top of the last tabula. This is stratigraphically younger material, some 50 m higher than fossils described two decades earlier, in which calcified polyps, each with 12 retracted tentacles, were noted. These more recently found structures show striking similarities in form and position to point, collaret and capstan spicules found in the soft tissues of modern pipe corals, i.e. the Octocorallia (Alcyonacea). Where preserved in a distinct pattern on top of the calcite tabulae, the spicular sclerites in Favosites occur in a particular sequence. Twelve individual, or sometimes six pairs of, triradiate point spicules have shrunk to a circlet near the middle of the calice (resting on the last, outermost, tabula). Surrounding the point spicules are 3-6 circlets of curved, usually perforated, lenticular collaret spicules; and surrounding these are scattered, much smaller, capstan spicules. The spicules display variability, probably ontogenetic, in their form and relative sizes; and they are more similar in form to calcareous spicules of alcyonacean corals than to those known from calcareous sponges. Structures with 12-fold radial symmetry in Heliolites, originally described by one of us as 'septal florets', consist of elements that are considered comparable with the point spicules found in Favosites. They have been recognized in ten species of Heliolites from Silurian (Wenlock-Ludlow) strata in the Canadian Arctic islands.

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Ordovician and Silurian Formations of Anticosti Island, Quebec

Cited by 30 publications

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A high-resolution, continuous δ¹³C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

A high-resolution, continuous δ¹³C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

Chapter 9 Coral biogeography in the Late Ordovician (Cincinnatian) of Laurentia

Spicules in Silurian Tabulate Corals From Canada, and Implications for Their Affinities

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Ordovician and Silurian Formations of Anticosti Island, Quebec

Cited by 30 publications

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A high-resolution, continuous δ13C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

A high-resolution, continuous δ13C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

Chapter 9 Coral biogeography in the Late Ordovician (Cincinnatian) of Laurentia

Spicules in Silurian Tabulate Corals From Canada, and Implications for Their Affinities

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A high-resolution, continuous δ¹³C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada

A high-resolution, continuous δ¹³C record spanning the Ordovician–Silurian boundary on Anticosti Island, eastern Canada