Theoretical growth of framboidal and sunflower pyrite using the R-package frambgrowth
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Framboids and sunflowers are the most ubiquitous shapes of sedimentary pyrite. Framboids are spherical aggregates of nanocrystals, while sunflowers are formed by overgrowth of framboids and represent intermediate stages in the transformation of framboids into euhedrae. The characterization of the size populations of these shapes provides critical information about the paleoredox conditions at time of formation and the subsequent changes in these conditions. This paper describes in detail an algorithm designed to model the growth and generate significant populations of both framboids and sunflowers, using functions of the statistical software R. The source code is provided as supplementary material to this paper. The algorithm uses several growth mechanisms based on dependence on or independence of the number of nanocrystals for framboids and the external diameter for sunflowers. Variability in the generated size populations depends on several parameters of the algorithm, such as the diameter of the nanocrystals, the initial diameter of the framboids and the maximum value of the random numbers. The resulting populations of framboids and sunflowers can be compared with data obtained from analysis of real samples in order to understand and model the genetic paleo-processes.
KeywordsPyrite framboids Pyrite sunflower R-package Redox conditions Computer simulation
This study is part of the work of the Research Group number 910197 of the Community of Madrid and the Complutense University of Madrid “Procesos Metalogenéticos en Sistemas Magmáticos e Hidrotermales.” Victor Cárdenes is grateful to his Marie Curie IEF grant 623082 TOMOSLATE, from the European Union’s Seventh Framework Programme for Research and Technological Development.
- Cárdenes V, Cnudde V, Merinero R, Dewanckele J, de Boever W, Cnudde JP (2015) Determination of the REDOX paleoconditions: a high resolution X-ray tomography study of micro pyrite occurrence. In: Long B, Francus P (eds) 2nd International conference on Tomography of Materials and Structures. INRS, Quebec, AbstractsGoogle Scholar
- Cárdenes V, Merinero R, De Boever W, Rubio-Ordóñez Á, Dewanckele J, Cnudde J-P, Boone M, Van Hoorebeke L, Cnudde V (2016) Characterization of micropyrite populations in low-grade metamorphic slate: a study using high-resolution X-ray tomography. Palaeogeogr Palaeoclimatol Palaeoecol 441:924–935CrossRefGoogle Scholar
- Cavalazzi B, Barbieri R, Cady SL, George AD, Gennaro S, Westall F, Lui A, Canteri R, Rossi AP, Ori GG, Taj-Eddine K (2012) Iron-framboids in the hydrocarbon-related middle Devonian Hollard Mound of the anti-atlas mountain range in Morocco: evidence of potential microbial biosignatures. Sediment Geol 263:183–193CrossRefGoogle Scholar
- Merinero R, Lunar R, Gonzalez FJ, Somoza L, Martinez-Frias J (2014) A mathematical algorithm to simulate the growth and transformation of framboidal pyrite: characterization of the biogenic influence in their size distributions. In: Pardo-Iguzquiza E, Heredia GAC, Moreno-Merino J, Duran JJ, Vargas-Guzman JA (eds) Mathematics of planet earth. Springer, Berlin Heidelberg, pp 793–796Google Scholar
- R Core Team (2016) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- RStudio Team (2015) RStudio: integrated development for R. RStudio Inc., Boston http://www.rstudio.com/
- Sawlowicz Z (1993) Pyrite framboids and their development: a new conceptual mechanism. Int J Earth Sci 82:148–156Google Scholar