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| Home > Articles > Published articles > Origin of the coloured karst fills in the neogene extensional system of ne iberia (Spain) |
(Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada) (Universitat Autònoma de Barcelona. Departament de Geologia) (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada) (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada) (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)| Date: | 2021 |
| Abstract: | Karst fills from the onshore Penedès Basin and offshore València Trough display red, pink, orange and ochre colours. Their Mössbauer spectra indicate that Fe contained in goethite is the dominant species in reddish-pink fills, whereas Fe contained in dolomite and clays is more dominant in the orange and ochre ones. The lower δ C values and higher Sr/ Sr ratios of the karst fills with respect to their host carbonates can reflect the input of soil-derived CO and an external radiogenic source into the karst system. This geochemical composition, together with the non-carbonate fraction of the fills, consists of authigenic and transported illite, illite-smectite interlayers, as well as kaolinite, chlorite, pyrite, quartz, ilmenite, magnetite, apatite and feldspar, account for a mixed residual-detrital origin of fills. This polygenic origin agrees with that of the terra rossa sediments described worldwide. The different colours of karst fills are attributed to fluctuations in the water table, which control the Eh/pH conditions in the karst system. Thus, reddish colours reflect low water table levels and oxidising episodes, and orange and ochre ones reflect high water table levels and more reducing episodes. The greenish colours of fills could be related to fluctuations in the Fe /Fe ratio. |
| Grants: | Agencia Estatal de Investigación PGC2018-093903-B-C22 Agencia Estatal de Investigación PID2020-118999GB-I00 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-824 Ministerio de Ciencia e Innovación RYC2018-026335-I |
| Rights: | Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.  |
| Language: | Anglès |
| Document: | Article ; recerca ; Versió publicada |
| Published in: | Minerals, Vol. 11, Issue 12 (December 2021) , art. 1382, ISSN 2075-163X |
