; II: subarkose; III: sublitharenite; IV: arkose; V: lithic arkose; VI: feldspathic litharenite; VII: litharenite.
On the basis ofthe framework composition and whole-rock geochemistry (major elements), the sandstone is classified as Quartzarenite
In the study area lithological units is outcrops the second to fourth periods, which from old to new are as follows: phyllite, ouartzite, paragneiss, marble, shell, sandstone with tufa, volcanic rocks, crystalline limestone locally with fosolina, metamorphic volcanic and tufa, cherty limestone, phyllite, metamorphic quartzarenite
, micaschist, metadolomite, amphibolite, limestone, shale and sandstone, schist hornfels, orthogneiss, granodiorite, oput rock, shale and phyllite sandstone, granite, granodiorite, diorite, dolomitic lime, radiolarit breccia, rodist lime, orbitoline, radiolarat, black and blue marl with limestone, alluvium.
The composition of siliciclastic rocks varies from quartzarenite
in coarser grain sizes (> 0.1 mm) to subarcose and arcose in fine grain sizes (< 0.1 mm).
The contact with the overlying carbonates of the Dorgali Fm has been placed where quartzarenites and lignite seams disappear (Costamagna and Barca, 2004).
It is formed by thick alternations of quartzose conglomerates and subordinated quartzarenites, passing in the upper ten metres of the section to dark pelites.
Rainbird, R.H., McNicoll, V.J., Heaman, L.M., Abbott, J.G., Long, D.G.E, and Thorkelson, D.J., 1997, Pan-continental river system draining Grenville Orogen recorded by U-Pb and Sm-Nd geochronology of Neoproterozoic quartzarenites
and mudrocks, northwestern Canada: Journal of Geology, v.
are predominant and kaolinite is abundant in their matrix.
1A for location), records a significant hiatus; in fact, at the base of this second petrological interval, the appearance of arenaceous rock fragments (very fine-grained quartzarenites lacking in volcanic lithics, similar to those typical of the "Basal Conglomerate"), and a much higher quartz content suggest wider dissection of the underlying volcanic plateaux, with erosion reaching into the Upper Carboniferous siliciclastics and the deeper-seated crystalline basement.
The base of the Servino Formation is characterized from Lake Como to the Manina mine section by discontinuous oligomict conglomerates, breccias and sandstones (Prato Solaro Member; Sciunnach et al, 1996, 1999b), which lack extensively towards the southeast, in the Brescian Prealps and nearby, where the basal Servino is represented by quartzarenites and other lithotypes (Cassinis, 1968b; De Donatis and Falletti, 1999), which will be described below (Figs.
Sandstones are quartzarenites and sedarenites containing variable amounts of carbonate rock fragments (Fig.
6) comprised mainly of quartzarenites and minor amounts of subarkoses (Fig.