Lower Carboniferous ostracodes from the Maritimes Basin of eastern Canada: A review

• Published in: Atlantic Geology
• Main Author: Dewey, Chris
• Format: Article in Journal/Newspaper
• Language: English
• Published: Atlantic Geoscience Society 1989
• Subjects: Canada; Newfoundland; Terre-Neuve
• Online Access: https://journals.lib.unb.ca/index.php/ag/article/view/1671

Lower Carboniferous ostracode assemblages of marine affinity occur in sediments of the Codroy Group in southwestern Newfoundland and the Windsor Group in central Nova Scotia. Three ostracode assemblages are defined from Nova Scotia and five from Newfoundland. The assemblages are described from biohermal and non-biohermal limestones and fine-grained sihciclastic lithologies. The assemblages can be characterised by their responses to varying degrees of physiological stress, and are dominated by members of the Paraparchitacea, although bairdiaceans, hoDinomorph and kirkbyacean palaeocopids and kloedenellaceans may be locally abundant. In the Maritimes Basin, the combined effects of tectonism, eustatic fluctuation and a semi-arid climate resulted in palaeoenvironments that were characterised by low temporal and spatial stability. As a consequence, total ostracode species richness relative to individual species abundances was low, and often expressed in the development of low grade communities that were controlled more by physical (allogenic) rather than biological (autigenic) parameters. Under these conditions the eurytopic paraparchitaceans were capable of producing large populations in physically harsh palaeoenvironments, whereas die more stenotopic bairdiaceans and palaeocopes only occurred when conditions were favourable. R᳧SUM᳧ Les s᳻diments des groupes de Codroy (sud-ouest de Terre-Neuve) et de Windsor (centre de la Nouvelle-᳧cosse) renferment des assemblages d'Ostracodes, ᳲ affinity marine, du Carbonifᳺre inf᳻rieur. On reconnait trois assemblages en Nouvelle-᳧cosse et cinq ᳲ Terre-Neuve. Ces assemblages proviennent de calcaires (biohcrmaux ou non) et de lithologies siliciclastiques ᳲ grain fin. On peut caract᳻riser ces assemblages par leurs re'ponses aux divers degr᳻e de stress physiologique. On y note la pr᳻lominance des repr᳻entants des Paraparchitacea malgr᳻ l'abondance locale des bairdiac᳻s, des pal᳻ocopid᳻ hollinomorphes et kirkbyaces ainsi que des kloedenellac᳻s. Dans le Bass in des Maritimes, la ...