Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones
This investigation studies the physical and chemical effect of salt weathering on biocalcarenites and biocalcrudites in the Basilica of Our Lady of Succour (Aspe, Spain). Weathering patterns are the result of salty rising capillary water and water lixiviated from pigeon droppings. Surface modificati...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-12-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/11/1/18 |
| _version_ | 1797543488555843584 |
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| author | David Benavente Marli de Jongh Juan Carlos Cañaveras |
| author_facet | David Benavente Marli de Jongh Juan Carlos Cañaveras |
| author_sort | David Benavente |
| collection | DOAJ |
| description | This investigation studies the physical and chemical effect of salt weathering on biocalcarenites and biocalcrudites in the Basilica of Our Lady of Succour (Aspe, Spain). Weathering patterns are the result of salty rising capillary water and water lixiviated from pigeon droppings. Surface modifications and features induced by material loss are observable in the monument. Formation of gypsum, hexahydrite, halite, aphthitalite and arcanite is associated with rising capillary water, and niter, hydroxyapatite, brushite, struvite, weddellite, oxammite and halite with pigeon droppings. Humberstonite is related to the interaction of both types of waters. Analysis of crystal shapes reveals different saturation degree conditions. Single salts show non-equilibrium shapes, implying higher crystallisation pressures. Single salts have undergone dissolution and/or dehydration processes enhancing the deterioration process, particularly in the presence of magnesium sulphate. Double salts (humberstonite) have crystals corresponding to near-equilibrium form, implying lower crystallisation pressures. This geochemical study suggests salts precipitate via incongruent reactions rather than congruent precipitation, where hexahydrite is the precursor and limiting reactant of humberstonite. Chemical dissolution of limestone is driven mainly by the presence of acidic water lixiviated from pigeon droppings and is a critical weathering process affecting the most valuable architectural elements present in the façades. |
| first_indexed | 2024-03-10T13:45:18Z |
| format | Article |
| id | doaj.art-36ddf50ceebb4f1f8d2968dd9c4b6bc1 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T13:45:18Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-36ddf50ceebb4f1f8d2968dd9c4b6bc12023-11-21T02:36:53ZengMDPI AGMinerals2075-163X2020-12-011111810.3390/min11010018Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous LimestonesDavid Benavente0Marli de Jongh1Juan Carlos Cañaveras2Department of Earth and Environmental Sciences, University of Alicante, 03690 Alicante, SpainSchool of Geographical & Earth Sciences, University of Glasgow, Glasgow G12 8QQ, UKDepartment of Earth and Environmental Sciences, University of Alicante, 03690 Alicante, SpainThis investigation studies the physical and chemical effect of salt weathering on biocalcarenites and biocalcrudites in the Basilica of Our Lady of Succour (Aspe, Spain). Weathering patterns are the result of salty rising capillary water and water lixiviated from pigeon droppings. Surface modifications and features induced by material loss are observable in the monument. Formation of gypsum, hexahydrite, halite, aphthitalite and arcanite is associated with rising capillary water, and niter, hydroxyapatite, brushite, struvite, weddellite, oxammite and halite with pigeon droppings. Humberstonite is related to the interaction of both types of waters. Analysis of crystal shapes reveals different saturation degree conditions. Single salts show non-equilibrium shapes, implying higher crystallisation pressures. Single salts have undergone dissolution and/or dehydration processes enhancing the deterioration process, particularly in the presence of magnesium sulphate. Double salts (humberstonite) have crystals corresponding to near-equilibrium form, implying lower crystallisation pressures. This geochemical study suggests salts precipitate via incongruent reactions rather than congruent precipitation, where hexahydrite is the precursor and limiting reactant of humberstonite. Chemical dissolution of limestone is driven mainly by the presence of acidic water lixiviated from pigeon droppings and is a critical weathering process affecting the most valuable architectural elements present in the façades.https://www.mdpi.com/2075-163X/11/1/18salt crystallisationpigeon droppingsrising dampstone conservationcalcarenite |
| spellingShingle | David Benavente Marli de Jongh Juan Carlos Cañaveras Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones Minerals salt crystallisation pigeon droppings rising damp stone conservation calcarenite |
| title | Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones |
| title_full | Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones |
| title_fullStr | Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones |
| title_full_unstemmed | Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones |
| title_short | Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones |
| title_sort | weathering processes and mechanisms caused by capillary waters and pigeon droppings on porous limestones |
| topic | salt crystallisation pigeon droppings rising damp stone conservation calcarenite |
| url | https://www.mdpi.com/2075-163X/11/1/18 |
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