| mhorn | Дата: Wednesday, 31.08.2011, 13:08 | Сообщение # 1 |
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| Dommergues J.-L., Guiomar M. (2011) La «Dalle à ammonites de Digne» (Réserve Naturelle Géologique de HauteProvence, France). Étude d’un site fossilifère d’importance patrimoniale // Revue de Paléobiologie, Genève. Vol. 30. no.1. P.261-293.
Pdf: http://www.ville-ge.ch/mhng/paleo/paleo-pdf/30-1/pal_30_1_13.pdf
The «Digne ammonite slab» is a spectacular fossiliferous feature of both scientific and patrimonial significance. The entire outcrop is protected by the «Réserve Naturelle Géologique de Haute-Provence» RNGHP. This remarkable slab, measuring about 320 m2, is the chief element in the outcrop. It exhibits more than 1550 cephalopods (many ammonites but also some nautilids) and bears a less obtrusive but diversified benthic fauna, mainly composed of epibenthic bivalves. Conversely, the striking ammonite fauna is, in taxonomic terms, rather monotonous with numerous Arietitidae (Coroniceras) but only sparse Schlotheimiidae (Angulaticeras). In fact the ammonite fauna is chiefly composed of a single highly dominant species, Coroniceras multicostatum (J. de C. sowerby, 1824) of which the abundant large specimens, sometime more than 50 cm in diameter, are the most obvious and famous component of the « Dalle ». This work is a monograph dedicated to the « Digne ammonite slab », in which palaeontological, palaeobiogeographical, palaeoecological, stratigraphical and sedimentological aspects are all considered. Although no specimens can deliberately be extracted from this highly protected locality, a morphometric study grounded in a significant set of data collected in situ allows the intraspecific variability of Coroniceras multicostatum to be explored. The results of this analysis suggest a short deposit duration, in geological terms, for the « Digne ammonite slab » fauna. As an experiment, the « Dalle » was recently 3D scanned and the palaeontological iconography is now composed both of computer-generated images of in situ specimens and of photographs of exemplars housed in the RNGHP collections.
Middle Jurassic - Lower Cretaceous ammonites & aptychi
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