Author:
Long D. G. F.,Copper Paul
Abstract
Marked facies changes occur in Late Ordovician strata, assigned to the uppermost Vaureal and Ellis Bay formations (Ashgill: Rawtheyan–Hirnantian) on Anticosti Island, Quebec. Western Anticosti features shales and carbonates, whereas outcrops along the eastern coast contain prominent, discontinuous, mixed siliciclastic–carbonate units. Detailed section measurement along the northeast coast allows, for the first time, accurate definition of seven new members within this uninterrupted sequence. Sands present in the upper Vaureal and lower Ellis Bay formations in the east appear to have deterred the growth of muddy-bottom brachiopod communities comparable to those in the western and central regions of Anticosti. Sand units within the upper Vaureal Formation contain 1 m diameter colonies of Paleofavosites; coeval small coral patch reefs are found in the central part of the island, where sands are absent. The uppermost Ellis Bay Formation of northeast Anticosti is marked by a shallow, subtidal, coral–algal oncolite bed or by small (2–4 m across, 1–2 m thick) local coral patch reefs, the tops of which have been used to define the Ordovician – Silurian boundary. No supratidal or intertidal sediments and faunas are evident in the Anticosti succession, suggesting that Late Ordovician sea-level drawdown was insufficient to provide shelf-emergent conditions in this region.
Publisher
Canadian Science Publishing
Subject
General Earth and Planetary Sciences
Cited by
59 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
1. A high-resolution sequence stratigraphic framework for the eastern Ellis Bay Formation, Canada: A record of Hirnantian sea-level change;Geological Society of America Bulletin;2024-02-24
2. Phosphorus cycling during the Hirnantian glaciation;Palaeogeography, Palaeoclimatology, Palaeoecology;2024-01
3. The morphologic and paleobiogeographic implications of a new early Silurian echinoid from Anticosti Island, Quebec, Canada;Canadian Journal of Earth Sciences;2022-12-01
4. A new species of Hirnantia (Orthida, Brachiopoda) and its implications for the Hirnantian age of the Ellis Bay Formation, Anticosti Island, eastern Canada;Journal of Paleontology;2022-10-11
5. Orbital forcing of late Early Devonian storm events on a mixed carbonate-siliciclastic shelf, Longmenshan area, Sichuan Province, China;GSA Bulletin;2022-03-02