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Chemical factors controlling the steady-state distribution of mixed carbonate-siliciclastic sediments in Bayona Bay (northwest Spain)
| Content Provider | Semantic Scholar |
|---|---|
| Author | Fernández-Bastero, S. Alejo, Izaskun Nombela, Miguel Ángel García-Gil, Soledad Francés, Guillermo Rubio, Belén Pérez-Arlucea, Marta Jiménez, Ricardo Rey, Daniel Bernabéu, Ana M. Pazos, O. Duport, Luis Gago Vilas, F. Santos, Arturo |
| Copyright Year | 1999 |
| Abstract | The relative space distributions of single mineral constituents in mixed terrigenous-carbonated sediments of the Bayona Bay have been analysed. In order to determine the existence of different mixing mechanisms, a study comparing the general sedimentary trends resulting from the average patterns and the single mineral behaviour, reflected in the single-mineral mapping, was carried out. The relative abundance of all mineral phases in surface sediment samples was first determined by quantitative X-ray powder diffraction data, using the Rietveld method. This procedure enabled us to create specific maps for both the minerals forming the terrigenous fraction and the different calcium carbonate polymorphs involved in the carbonatic component. A cross-linked behaviour between the carbonate facies and the terrigenous minerals involved in the calcium carbonate generation was found, suggesting the existence of a chemical control mechanism which, through dissolution-crystallization processes, constrains the mixed environment’s long-term evolution. In the general framework of the region studied, these relations operate for the relative amount of plagioclase to calcium carbonate. The existence of dissolution and growth between both minerals, favoured by the high rate of removal, is proposed, yielding a final crossed pattern, representative of the steady-state. Furthermore, a specific analysis, restricted to the region of low rate of material removal and maximum amount of intermixed sediments, clearly shows an anisotropic distribution for every calcium carbonate polymorph (calcite and aragonite). These correlate with the biotite distribution, and can be connected to local variations in seawater Mg/Ca ratio, induced by biotite weathering. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.revistas.ieo.es/index.php/boletin_ieo/article/viewFile/304/299 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
