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| Buurman, P.. |
| Several pieces of fossil wood have been analyzed with X-ray diffraction and were grouped on the basis of mineralogical composition. Various mineralizations were studied in thin sections and by means of the scanning electron microscope. Wood-opals appear to show a structure preservation that points to replacement of cell walls by silica. The wood-opals are mineralogically characterized as 'disordered tridymite'. Other mineralizations, such as chalcedony, quartz, carbonates, phosphates and iron-oxydes and -hydroxydes show characteristics of filling-in. Various mineralization processes are discussed. |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.24. |
| Ano: 1972 |
URL: http://www.repository.naturalis.nl/record/317496 |
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| Buurman, P.. |
| Fossil driftwood from Sarmatian (Late Miocene) gravel deposits near Yakuplu, Turkey, ranges between lignitic and opaline. Opalization occurred in various stages of decay. The stage of decay of the wood and the eventual admixture of detritic clay influenced the crystallinity and the dehydration characteristics of the opal. Opals influenced by the host rock seem to have montmorillonitic suprastructures. Opalization was probably the result of the weathering of volcanic ash layers in the overlying strata. |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.30. |
| Ano: 1975 |
URL: http://www.repository.naturalis.nl/record/317409 |
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