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| Grégoire, Ch.. |
| 1. The pyrolytic changes in the organic and mineral components of mother-of-pearl of the modern <i>Nautilus</i> have been studied with the transmission and scanning electron microscopes in 86 groups of samples. 2. Pyrolysis was performed in the range of 100 °C to 900 °C for periods extending from a few minutes to 53 days, in four sets of experiments : 1. samples boiled in sea water; 2. samples heated dry in open vessels; 3. samples heated dry in tubes sealed under vacuum; 4. samples heated with sea or distilled water in tubes sealed under vacuum. 3. The present observations confirm and extend those of previous studies on the thermal changes in the ultrastructure of the interlamellar conchiolin matrices: a. Conchiolin is thermoresistant. It does... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1972 |
URL: http://www.vliz.be/imisdocs/publications/295162.pdf |
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| Grégoire, Ch.. |
| 1. This paper is an electron microscope study of the alterations produced by temperatures in range of 100°C to 900°C in mother-of-pearl of the modern <i>Nautilus</i> shell. 2. Fragments of nacreous layers of the shell wall in the living chamber were exposed for 5 minutes to 21 days to dry heat in open vessels and in quartz tubes sealed under vacuum or argon. Other fragments were boiled in sea mud and sea water. 3. In open vessels and in sealed tubes, conversion of aragonite into calcite took place in the samples heated at 400 °C and above. In the 600 °C-900 °C samples, calcite was mixed with varying amounts of calcium oxide. With elevation of temperature, the original hard, compact and stratified mother-of-pearl became progressively brittle,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diagenesis; Metamorphism; Nacre; Nautilus. |
| Ano: 1968 |
URL: http://www.vliz.be/imisdocs/publications/294745.pdf |
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| Grégoire, Ch.. |
| Remnants of decalcified nacreous layers from Ordovician, Devonian, Carboneferous (including Pennsylvanian), Permian, Jurassic and Cretaceous, nautiloid and ammonoid shells, examined in the electron microscope, consists of various, biuret-positive structures, which reflect degrees in degradation of the original conchiolon sheets. Identification of these structures as altered nacreous concholin and discrimination from contaminating structures of foreign organisms, a frequent finding in fossil shells, were based on detection of similar structural modifications in the Recent <i>Nautilus</i> shell, in well preserved shells of Pennsylvanian and Mesozoic cephalopods and in alterations produced artificially in experimental diagenesis of the Recent... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fossils; Paleozoic; Cephalopoda. |
| Ano: 1966 |
URL: http://www.vliz.be/imisdocs/publications/289080.pdf |
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