The La Voulte Lagerstätte (Callovian): Evidence for a deep water setting from sponge and crinoid communities
| Autor: | Christian Gaillard, Jean Vannier, Sylvain Charbonnier, Pierre Hantzpergue, Jean-Paul Bourseau |
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| Přispěvatelé: | PaleoEnvironnements et PaleobioSphere (PEPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2007 |
| Předmět: |
010506 paleontology
Lagerstätte Callovian Seamount Jurassic 010502 geochemistry & geophysics Oceanography 01 natural sciences Bathyal zone Bathyal Sedimentary depositional environment Paleontology Stalked crinoids 14. Life underwater Ecology Evolution Behavior and Systematics 0105 earth and related environmental sciences Earth-Surface Processes geography geography.geographical_feature_category biology Hexactinellid biology.organism_classification Crinoid Siliceous sponges Sponge Chenier France [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology Geology |
| Zdroj: | Palaeogeography, Palaeoclimatology, Palaeoecology Palaeogeography, Palaeoclimatology, Palaeoecology, Elsevier, 2007, 250, pp.216-236. ⟨10.1016/j.palaeo.2007.03.013⟩ |
| ISSN: | 0031-0182 |
| DOI: | 10.1016/j.palaeo.2007.03.013 |
| Popis: | International audience; The siliceous sponges and crinoids from the Chénier Ravine (France, Lower Callovian) are used here as biological markers to characterize the palaeoenvironment of the adjacent and contemporaneous La Voulte Lagerstätte that is remarkable for its unique soft-bodied fauna (e.g. worms, cirrate octopods, vampire squids). Sponges are abundant with dominant hexactinellids (80%) and lithistids (20%). Four lines of fossil evidence, supported by Recent analogues, indicate that this sponge community inhabited deepwater setting under dysphotic or aphotic conditions: (1) the dominance of hexactinellids; (2) the prevalence of cone-shaped and erect morphologies that usually characterize Recent bathyal sponges; (3) the close similarities with Recent hexactinellids from the continental slope and; (4) the lack of encrustation by photophilic organisms. Attachments of sponges on hard substrate (e.g. crystalline basement) and their preservation in soft sediments (e.g. muds) indicate heterogeneous bottom conditions. The Chénier fauna also contains small stalked, asymmetric cyrtocrinid crinoids that are known to live on hard substrates in bathyal environments such as the SW Pacific steep seamounts. Convergent palaeoenvironmental clues obtained from both crinoids and siliceous sponges support the notion that the La Voulte area, including the La Voulte Lagerstätte, was situated in the upper part of the bathyal zone near the slope-basin transition with a water depth most probably exceeding 200 m. Supporting evidence from heterogeneous substrates and complex fault systems indicate a depositional environment along the external part of the slope where steep topographies and blocks usually favour the settlement of cyrtocrinid crinoids and hexactinellid sponges. La Voulte may therefore be one of the rare and extremely precious Mesozoic Lagerstätten to have fossilized a deep marine environment |
| Databáze: | OpenAIRE |
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