Skip to Main Content
Book Chapter

The deep-marine glaciogenic Gaskiers Formation, Newfoundland, Canada

By
Shannon L. Carto
Shannon L. Carto
Search for other works by this author on:
Nick Eyles
Nick Eyles
Search for other works by this author on:
Published:
January 01, 2011

Abstract

In eastern Canada, the Neoproterozoic Gaskiers Formation (Fm.) consists of a thick diamictite–turbidite succession (250–300 m thick) that occurs within the deep-marine predominantly volcaniclastic turbidite units of the Conception Group (4–5 km thick). These rocks are well exposed on the coast of the Avalon Peninsula in eastern Newfoundland. The thick succession is considered by some to represent the final Neoproterozoic glacial event, known as the Gaskiers Glaciation c. 582–585 Ma. The Gaskiers Fm. appears to have accumulated in a volcanically-influenced arc-related basin within the confines of the Proterozoic peri-Gondwanan Avalon terrane, before rifting away from the Gondwanan margin in the early Palaeozoic, but it is not clear whether it was adjacent to the West African Craton or the Amazon Craton. It has also been argued that Avalon had already rifted from Gondwana by the late Proterozoic.

Glacially striated clasts, dropstones, and chatter-marked garnets identify a glaciated source area, and clasts and matrix are of volcanic origin; pyroclastic flows and volcanic bombs are also present. As a result, there is a growing consensus that the Gaskiers Fm. records local glaciation of a high relief volcanic topography, owing its origin to the episodic downslope reworking of volcanic and glacial debris into a deep, rapidly subsiding basin. The volcanic nature of these deposits implies that local volcanic activity was coeval with deposition. A minimum age of the Gaskiers Fm. is constrained by a diverse assemblage of Ediacaran-type fossils in the upper Conception Group dated at c. 565±3 Ma and in the lower St. John's Group, which overlies the Conception Group. A maximum age for the Gaskiers is provided by a U–Pb date of 606 +3.7/–2.9) Ma in the Harbour Main volcanic rocks underlying the Gaskiers Fm. A thin limestone bed has also been identified at two localities in Conception Bay directly overlying the diamictite yielding strongly negative δ13C values.

You do not currently have access to this article.

Figures & Tables

Contents

Geological Society, London, Memoirs

The Geological Record of Neoproterozoic Glaciations

Emmanuelle Arnaud
Emmanuelle Arnaud
University of Guelph, Canada
Search for other works by this author on:
Galen P. Halverson
Galen P. Halverson
McGill University, Canada
Search for other works by this author on:
Graham Shields-Zhou
Graham Shields-Zhou
University College London, UK
Search for other works by this author on:
Geological Society of London
Volume
36
ISBN electronic:
9781862394117
Publication date:
January 01, 2011

GeoRef

References

Related

Citing Books via

A comprehensive resource of eBooks for researchers in the Earth Sciences

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal