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Clay saline diagenesis in lake Plio-Pleistocene sediments rich in organic matter from the Guadix-Baza Basin (Betic Cordillera, SE Spain).
- Source :
-
Applied Clay Science . Sep2020, Vol. 195, pN.PAG-N.PAG. 1p. - Publication Year :
- 2020
-
Abstract
- This study presents a mineralogical analysis of the effect of hypersaline lake environments rich in organic matter on the mineral transformations in sediments of the eastern part of the Guadix-Baza Basin (Betic Cordillera). Dark sediments with fragments of organic matter are rich in phyllosilicates (K-white mica, illite-smectite mixed layers, –I/S– minor amounts of paragonite, palygorskite, chlorite and kaolinite) and contain quartz, feldspars, and framboidal pyrite. X-ray diffraction patterns of I/S (R0 type, disordered) revealed a continuous between the positions of pure smectite and 30% of illite layers. Chemical composition of I/S mixed layers indicated a significant beidellitic substitution of Si by AlIV, Fe + Mg > 1 atoms per formula unit (a.p.f.u.) and K content up to 0.42 a.p.f.u. These data suggested the presence of a minor and variable amount of illitic layers among the major smectitic ones. Saline waters of the lake and the reducing environment of the sediment favored Mg and Fe2+ uptake, generating octahedral negative charge, which together with the beidellitic substitution would provide clay layer negative charge enough to admit K incorporation in the interlayer, hence the beginning of a diagenetic low temperature illitization. • Hypersaline environments promoted low temperature diagenetic transformations. • Mg and Fe2+ uptake in smectites favored K incorporation in the interlayer. • Illite-smectite mixed layers indicate the beginning of a diagenetic illitization. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01691317
- Volume :
- 195
- Database :
- Academic Search Index
- Journal :
- Applied Clay Science
- Publication Type :
- Academic Journal
- Accession number :
- 144689349
- Full Text :
- https://doi.org/10.1016/j.clay.2020.105739