Low temperature, authigenic illite and carbonates in a mixed dolomite-clastic lagoonal and pedogenic setting, Spanish Central System, Spain

Abstract

Publisher's version available at:__________________________________________________________________________________________ Please note that where the full text version provided on GALA is not the final published version, the version made available will be the most up-to-date full-text (post-print) version as provided by the author(s). Where possible, or if citing, it is recommended that the publisher's (definitive) version be consulted to ensure any subsequent changes to the text are noted. Citation for this version held on GALA:Huggett, J, Cuadros, J, Gale, Andrew S, Wray, David S and Adetunji, Jacob (2016) Low temperature, authigenic illite and carbonates in a mixed dolomite-clastic lagoonal and pedogenic setting, Spanish Central System, Spain. London: Greenwich Academic Literature Archive. Available at: http://gala.gre.ac.uk/15611/ __________________________________________________________________________________________ Contact: gala@gre.ac.uk 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 ABSTRACT 19 20The aim of this study was to further our understanding of the pedogenic and 21 lacustrine modification of clay minerals. Some of these modifications are of 22 special interest because they constitute reverse weathering reactions, rare in 23 surface environments, and because there is not yet an accurate assessment of 24 their global relevance in mineralogical and geochemical cycles. For this study, 25 two sections from the Central System in Spain were selected. Both are sections 26 through the Uppper Cenomanian-Turonian mixed clastic and carbonate 27 succession, containing both calcite and dolomite, in the Sierra de Guadarrama. 28Mid-Turonian sea level fall resulted in the formation of a coastal plain 29 environment in which extensive pedogenesis occurred around saline lagoons. 30The mineralogical changes that have occurred as a result of sedimentation in 31 saline lagoons and as a consequence of pedogenesis are described. Textural 32 relationships indicate that the dolomite cement pre-dates the calcite. Silicate 33 minerals are represented by quartz, kaolinite, illite-smectite, illite, minor 34 plagioclase and alkali feldspar, and trace chlorite and palygorskite. There is a 35 positive correlation between the intensity of pedogenesis and the proportion of 36 illite in the clay assemblage in one of the sections, indicating pedogenic 37 illitisation. In this section, the intensity of the illitisation process increases up, 38 reaching a maximum where pedogenesis is most intense in the middle part, and 39 then decreases as marine influence increases towards the top of the Alc...

Low Temperature Illitization through Illite-Dioctahedral Vermiculite Mixed Layers in a Tropical Saline Lake Rich in Hydrothermal Fluids (Sochagota Lake, Colombia)

“…In sedimentary and diagenetic systems, clay reactions can be influenced by elevated water salinity and oxygen-depleted conditions that favor reducing transformations (e.g., of Fe) mediated by microorganisms [4][5][6]. High concentration of cations and biological activity are frequently due to specific sediment composition, hydrology, and climatic conditions, such as those that can be generated in saline lakes or mangrove soils [6][7][8][9]. In these environments with hydrologically restricted conditions, clays of detrital origin interact with high salinity waters, producing phase authigenesis.…”

Sedimentological Characteristics And Paleoenvironmental Implication Of Triassic Vertebrate Localities In Villány (Villány Hills, Southern Hungary)

“…Based on its mineral content (dominated by non-carbonate minerals), macrofeatures (root moulds, fine-grained layers with Liesegang-bands and mottles) and colour, this horizon is interpreted as calcic paleosol (similar to Klappa 1980a, b;Wright 1994;Kraus 1999). The red colour implies the abundance of ferric oxides indicating oxidizing conditions and well-drained environment during pedogenesis (Wright 1994;Kraus 1999;Zand-Moghadam et al 2014; GEOLOGICA CARPATHICA, 2019, 70, 2, 135-152 Huggett et al 2016). The laminated claystone horizons in the uppermost part of bed 14 can be interpreted as dolocretes (Fig.…”

“…8E), dolocretes, as well as the vertical root moulds indicate that these silty claystone sediments have been subaerially exposed, during which they were modified by pedogenetic processes. The peritidal environment is regularly exposed to subaerial conditions during low sea-level stages resulting in the development of thin paleosol horizons on top of the carbonate sediments (Ginsburg 1975;Wright 1994;Blanchard et al 2016;Huggett et al 2016).…”

Palaeo-environmental evolution of Central Asia during the Cenozoic: New insights from the continental sedimentary archive of the Valley of Lakes (Mongolia)

“…The origin of Ilt-Smc in the Valley of Lakes sediments is difficult to constrain: it could have been formed during low temperature pedogenesis from smectite or kaolinite precursors of 'zero' age (Huggett et al, 2016), which were deposited due to wind (allochthonous clay source) or soil water (autochthonous source) action, through a dissolution-(re)precipitation mechanism.…”