Non-stable fragments are represented by subangular K-feldspar grains (orthoclase and microcline) with [M.sub.d] 0.20 mm, polysynthetically twinned plagioclase, flakes of muscovite and biotite and subangular to subrounded clasts of
lutite. Both feldspars are at different stages kaolinised and sericitised.
The Mesozoic-Tertiary cover bed presents greater lithological diversity, although the areas closest to the axis have a predominance of limestone, dolomite, marl, marly limestone, sandstone, clay--with and without evaporites--,
lutite, conglomerate and turbidite (Fig.
In the Central Baltoscandian Confacies Belt this event coincides with coarsening of the calcareous sediment from
lutite to fine-grained shelly sand (Jaanusson 1982b, pp.
In this figure, it can be seen that in the presence of cemented sandstone layer introduced in
lutite rock, (Fig.
The soils of the region are basically a rocky substrate of Upper Cretaceous
lutite or siltstone.
The second group is comprised of outcrops of sandstone, limestone, and argillite (
lutite).
Especially, phyllosilicates with properties of clay minerals in the sediment-forming processes and in the argillosphere affected by post-depositional processes are a great theme, which attracts attention of geologists and other experts examining argillaceous and
lutite accumulations developed through the geological history of the Earth.
Higher up in the unit, marly limestone and marls with
lutite and thin-bedded bioclastic limestone levels alternate.
Along the southwest border of the Aguilar Basin, these carbonate units appear intercalated with
lutite and calcareous conglomerate facies with frequently reddish marine Jurassic clasts, defined as the Becerril Member.
In dark
lutite layers locally associated with this facies, total organic carbon contents (T.O.C.) have been determined.
4), which comprises a 106 m thick basal
lutite sequence dominated by red and green
lutites, with some sandstone alternations deposited by fluvio-alluvial processes.