| Titre | Palaeoenvironmental distribution of Proterozoic microfossils, with an example from the Agu Bay Formation, Baffin Island |
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| Auteur | Butterfield, N J; Chandler, F W |
| Source | Palaeontology vol. 35, pt. 4, 1992 p. 943-957 |
| Image |  |
| Année | 1992 |
| Séries alt. | Commission géologique du Canada, Contributions aux publications extérieures 222091 |
| Document | publication en série |
| Lang. | anglais |
| Media | papier |
| Province | Nunavut |
| SNRC | 47E/03; 47E/04; 47E/05; 47E/06; 47E/11; 47E/12; 47E/13; 47E/14; 47F |
| Région | île de Baffin |
| Lat/Long OENS | -88.0000 -82.0000 71.0000 70.0000 |
| Sujets | schistes; ampélites; microfossiles; taxonomie; fossiles; plans de litage; paléoécologie; paléoenvironnement; biostratigraphie; milieu sédimentaire; géologie générale; géologie marine; sédimentologie;
paléontologie |
| Illustrations | cartes de localisation; coupes transversales, stratigraphique; photomicrographies; graphiques; diagrammes schématiques |
| Programme | CRSNG Conseil de recherches en sciences
naturelles et en génie du Canada |
| Diffusé | 1992 01 01 |
| Résumé | (disponible en anglais seulement)
A shale sample from the Black Shale Member of the c. 1250 Ma Agu Bay Formation, Fury and Hecla Group, north-west Baffin Island contains abundant, well-preserved
microfossils. The assemblage is dominated by small leiosphaerid acritarchs of which c. 15 per cent show structures here interpreted as medial split release structures. Colonial unicells and larger spheroidal acritarchs are uncommon, and filamentous
microfossils extremely rare. A single specimen of the highly distinctive acritarch Valeria lophostriata extends the geographic range of this taxon and, in concert with geochronological and chemostratigraphical data, constrains the timing of Fury and
Hecla deposition to the early Late Riphean. The overall habit of the Black Shale Member assemblage, including the even bedding plane distribution of fossils, supports the sedimentological and stratigraphical evidence for a mid to outer shelf
depositional environment. Incorporating these findings into a review of Proterozoic shale-hosted microfossils reveals a distinct depth/diversity trend in assemblage structure such that five broad zones can be recognized extending from restricted
nearshore to basinal environments. The depositional environments of the Neoproterozoic Mineral Fork Formation, Utah, and the terminal Proterozoic Pertatataka Formation, Australia, are reconsidered using this palaeoecological measure of depositional
environment. |
| GEOSCAN ID | 215149 |
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