Weathering evolution in lutites of the K/Pg transition red beds of the Tremp Group (Tremp-Isona Basin, south Pyrenees)

Bastida, J.; Linares, Rogelio; Buendía, Ángel María López; Osácar, María Cinta; Rosell, Joan; Zarroca, Mario

doi:10.1180/claymin.2017.052.1.08

Cited by 3 publications

(1 citation statement)

References 40 publications

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“…The illite crystallinity values and other proxies eventually with chemical weathering index data have been used to evaluate weathering and/or to constrain sediment provenances or to evaluate climate evolution, e.g., [222][223][224][225][226][227][228][229][230][231][232][233].…”

Section: Weathering Soils Provenancementioning

confidence: 99%

Applications of X-ray Powder Diffraction Microstructural Analysis in Applied Clay Mineralogy

Bastida,

Pardo-Ibañez

2024

Minerals

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Clay minerals and sheet silicates are the main constituents of lutites and clays. These materials are relevant in earth science research as well as in economic geology because of the great variety of applications, based on their particular features at different levels of aggregation in mineral assemblages and on the microstructural and structural characteristics of the mineral constituents frequently characterized by micro- and nanocrystalline appearance. Thus, X-ray diffraction is a main tool for fundamental and applied research of these materials. The present review concerns their microstructural research from powder X-ray diffraction data.

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Section: Weathering Soils Provenancementioning

confidence: 99%

Applications of X-ray Powder Diffraction Microstructural Analysis in Applied Clay Mineralogy

Bastida,

Pardo-Ibañez

2024

Minerals

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The Early–Middle Miocene climate as reflected by a mid‐latitude lacustrine record in the Ebro Basin, north‐east Iberia

Arenas,

Osácar,

Pérez‐Rivarés

et al. 2024

The Depositional Record

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This contribution examines the climate variations reflected by a mainly lacustrine succession spanning from 17.73 to 14.0 Ma in north‐east Iberia, thus encompassing the Miocene Climatic Optimum (MCO). The study is based on the δ13C and δ18O composition of an array of carbonate facies and marl samples, complemented with sedimentological analysis, illite crystallinity index and magnetic susceptibility data. The onset and ending of the MCO have been detected at ca 17.10‐17.06 Ma and 14.56 Ma, roughly equivalent to the boundaries in the marine record, although with relatively short lags. The variability of the data series evidenced changes in humidity and air temperature through the MCO, some of which coincided with similar variations in other records. Specifically, an evolving positive shift in δ13C values, from 16.5 to 14.5 Ma, seems to fit the Monterey excursion observed in marine records. Likewise, increases in δ18O values between 16.8 and 16.5 Ma and between 14.85 and 14.56 Ma in the study succession concurred with warming intervals recorded in palaeosols of Central Europe, emphasising the coincidence with the temperature maximum at ca 16.6 Ma. A general decline in temperature and an increase in humidity are detected from 14.56 Ma, both with steeper trends until 14.41 Ma then more gradual onwards, indicating the beginning of the Middle Miocene Climatic Transition. These results shed light upon the tightly coincidental features between terrestrial and marine records over those time intervals and, more importantly, highlight the earlier warming and the faster cooling experienced by the lake system as compared with the marine record. These findings provide further evidence to help infer palaeoclimate conditions on a much broader reach than the regional context.

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Pedogenic continental red beds: How, why and when red? Redox geochemistry and quantitative colour analysis of the Old Red Sandstone, South Wales, UK

Bábek,

Ackerman,

Šimíček

et al. 2024

Sedimentology

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Continental red beds are coloured by secondary Fe(III)‐oxy‐hydroxides (mainly hematite) which makes them excellent archives of ancient near‐surface redox conditions. However, colour is often treated as a subjective physical property, and opinions differ widely as to the environment and timing of colouration of the red beds. This study utilizes diffuse spectral reflectance to address the degree of reddening (hematitization) of the Siluro‐Devonian Old Red Sandstone representing a dryland fluvial system with abundant palaeo‐Vertisols, coinciding with the period of land colonization by vascular plants. The hematitization was studied along with the stratigraphy, facies, pedogenic features, petrology, element and Molybdenum isotope geochemistry. The mudstones and palaeosols are typically red while sandstones are often grey. The red colouration corresponds to approximately 30 to 36% of red band (625 to 700 nm) reflectance and high hematite to goethite ratios. The red sediments contain hematitized biotite, submicronic hematite in mudstone and sandstone matrix, and hematite cement in calcretes. The hematitization was synchronous with formation of pedogenic mudcracks, Vertic slickensides, calcretes, reduction spots, sometimes hydrodynamic reworking, and accompanied by local (grain‐scale) depletion in Fe(II), enrichment in Fe(III), and mobilization of U, V, As, Cu, Zn and Mo. It is estimated that the hematite growth was rapid (several hundred to thousand years) but the average sedimentation rates were low (approximately 3 to 10 cm/kyr). Erosion led to development of reactivation surfaces separating layers with contrasting hematite content and geochemistry. It is suggested that high rates of pedogenesis and low sedimentation rates favour the reddening and may represent an important control on the formation of continental red beds. Limited levels of soil waterlogging, and the published δ13C values (−9 to −12‰ Vienna Pee Dee Belemnite) of the pedogenic carbonate, might reflect the changes in the nature of the soil biomantle during the early Devonian land colonization by vascular plants.

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Weathering evolution in lutites of the K/Pg transition red beds of the Tremp Group (Tremp-Isona Basin, south Pyrenees)

Cited by 3 publications

References 40 publications

Applications of X-ray Powder Diffraction Microstructural Analysis in Applied Clay Mineralogy

Applications of X-ray Powder Diffraction Microstructural Analysis in Applied Clay Mineralogy

The Early–Middle Miocene climate as reflected by a mid‐latitude lacustrine record in the Ebro Basin, north‐east Iberia

Pedogenic continental red beds: How, why and when red? Redox geochemistry and quantitative colour analysis of the Old Red Sandstone, South Wales, UK

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