Environmental and correlative significance of a non-marine algal limestone (Westphalian D), Sydney Coalfield, Cape Breton Island, Nova Scotia
DOI:
https://doi.org/10.4138/1559Abstract
The occurrence of an algal limestone containing stromatolites within the Morien Group (Sydney Coalfield) is reported for the first time. Three distinct morphologic forms of stromatolite (pinnacle, mat and detached) and their stratigraphic variation are described. Variation in clast type and size, biota and elements within the algal limestone is interpreted as evidence for the growth of stromatolites on the shore of an ephemeral, fresh to brackish lake, subject to fluctuating water levels. Pinnacle and mat forms developed on substrate irregularities. A bivalve and ostracode fauna in mudatones and siltstones above and below the algal limestone indicates a correlation with the Anthraconauta tenuis chronozone of Britain (Westphalian D) and corroborates on age derived from associated macro- and microflora. RÉSUMÉ Four la première fols, on rapporte la présence de stromatolithes dans un calcaire à algues du groupe Morien (houillière de Sydney). Trois types morphologlques de stromatolithes (pinacle, paillasson, détache) et leur variation stratigraphique sont décrité. On interprète la variation dans la faune, la flore, les éléments, le type et la grosseur des fragment à au seln du calcaire à algues comme preuve de la croissance des stromatolithes sur les rives d'un lac éphemère, d'eau douce à saunâtre et sujet à des variations périodiques du niveau d'eau. Les formes en pinacle et en paillasson s'établirent sur les irrégularités du substrat. Une faune de bivalves et d'ostracodes dans lea roches arglleuses superposées et sous-jacentes au calcaire à algues est corrélative avec la zone chronologique Anthraconauta tenuis de Grande-Bretagne (Westphalien D) et confirme l'âge déduit de la macro et la micro flore. [Traduit par le journal]Downloads
Published
How to Cite
Issue
Section
License
All material contained in Atlantic Geology is copyrighted by the journal. Permission to photocopy for internal or personal use or for the internal or personal use of specific clients is granted by Atlantic Geology to libraries and other users registered with the Copyright Clearance Center (CCC), provided that the stated fee per copy is paid directly to the CCC, 21 Congress Street, Salem, Massachusetts 01970 USA. Other requests should be addressed to one of the journal editors, or sent to Atlantic Geology, Box 116, Acadia University, Wolfville, NS, Canada B4P 2R6. Permission to use a single graphic for which Atlantic Geology owns copyright is considered “fair dealing” under the Canadian Copyright Act and “fair use” by the journal, and no other permission need be granted, subject to the image being appropriately cited in all reproductions. The same fair dealing/fair use policy applies to sections of text up to 100 words in length.