Papineau, Dominic;
(2024)
Chemically Oscillating Reactions as a New Model for the
Formation of Mineral Patterns in Agate Geodes and Concretions.
Minerals
, 14
, Article 203. 10.3390/min14020203.
Preview |
PDF
Papineau_2024_Minerals_COR_for_geodes_and_concretions.pdf - Published Version Download (14MB) | Preview |
Abstract
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.
| Type: | Article |
|---|---|
| Title: | Chemically Oscillating Reactions as a New Model for the Formation of Mineral Patterns in Agate Geodes and Concretions |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3390/min14020203 |
| Publisher version: | https://doi.org/10.3390/min14020203 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Abiotic; biosignature; origin of life; concretion; agate geodes |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10187361 |
Archive Staff Only
 |
View Item |
