Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions
Agate geodes contain spheroidal patterns characterized by spectacularly coloured and circularly concentric laminations with radially aligned quartz crystals, yet the origin of these geometric patterns has remained enigmatic. Here, detailed comparisons are documented between these kinds of patterns i...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-02-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/14/2/203 |
| _version_ | 1797297401475629056 |
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| author | Dominic Papineau |
| author_facet | Dominic Papineau |
| author_sort | Dominic Papineau |
| collection | DOAJ |
| description | Agate geodes contain spheroidal patterns characterized by spectacularly coloured and circularly concentric laminations with radially aligned quartz crystals, yet the origin of these geometric patterns has remained enigmatic. Here, detailed comparisons are documented between these kinds of patterns in a selection of geodes and concretions and those produced by abiotic chemically oscillating reactions. We find strikingly comparable self-similar, fractal patterns in both natural volcanogenic geodes and sedimentary concretions as well as in these benchtop experiments. In addition, the mineralogical composition of patterns and associated organic matter point to the oxidation of organic compounds in both geodes and concretions. This process occurred during diagenetic or supergene alteration, and it is consistent with spontaneous and abiotic chemically oscillating reactions. It is concluded that the oxidation of organic acids was involved in the formation of these patterns and that these rocks indicate oxidation–reduction reactions involving organic carbon, which itself may be abiotic or biological in origin. Hence, agate geodes and concretions represent the abiotic biosignatures of possible biological origin in volcanic and sedimentary rocks. |
| first_indexed | 2024-03-07T22:19:47Z |
| format | Article |
| id | doaj.art-5c539adb25ef4ea780becaf969c1413c |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-07T22:19:47Z |
| publishDate | 2024-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-5c539adb25ef4ea780becaf969c1413c2024-02-23T15:28:44ZengMDPI AGMinerals2075-163X2024-02-0114220310.3390/min14020203Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and ConcretionsDominic Papineau0London Centre for Nanotechnology, Department of Earth Sciences, and Centre for Planetary Science, University College London, London WC1H 0AH, UKAgate geodes contain spheroidal patterns characterized by spectacularly coloured and circularly concentric laminations with radially aligned quartz crystals, yet the origin of these geometric patterns has remained enigmatic. Here, detailed comparisons are documented between these kinds of patterns in a selection of geodes and concretions and those produced by abiotic chemically oscillating reactions. We find strikingly comparable self-similar, fractal patterns in both natural volcanogenic geodes and sedimentary concretions as well as in these benchtop experiments. In addition, the mineralogical composition of patterns and associated organic matter point to the oxidation of organic compounds in both geodes and concretions. This process occurred during diagenetic or supergene alteration, and it is consistent with spontaneous and abiotic chemically oscillating reactions. It is concluded that the oxidation of organic acids was involved in the formation of these patterns and that these rocks indicate oxidation–reduction reactions involving organic carbon, which itself may be abiotic or biological in origin. Hence, agate geodes and concretions represent the abiotic biosignatures of possible biological origin in volcanic and sedimentary rocks.https://www.mdpi.com/2075-163X/14/2/203abioticbiosignatureorigin of lifeconcretionagate geodes |
| spellingShingle | Dominic Papineau Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions Minerals abiotic biosignature origin of life concretion agate geodes |
| title | Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions |
| title_full | Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions |
| title_fullStr | Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions |
| title_full_unstemmed | Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions |
| title_short | Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions |
| title_sort | chemically oscillating reactions as a new model for the formation of mineral patterns in agate geodes and concretions |
| topic | abiotic biosignature origin of life concretion agate geodes |
| url | https://www.mdpi.com/2075-163X/14/2/203 |
| work_keys_str_mv | AT dominicpapineau chemicallyoscillatingreactionsasanewmodelfortheformationofmineralpatternsinagategeodesandconcretions |