L'ARENARIA DI PALAZZO DUCALE IN CAMERINO (MC): CARATTERISTICHE MINERALOGICO-PETROGRAFICHE E CONSIDERAZIONI SULLO STATO DI CONSERVAZIONE

Abstract

Petrographical, mineralogica!, chemical and electron microscopie studies on both the sandstones of the Palazzo Ducale at Camerino and those cropping out in the sorrounding areas have been carried out in order to evaluate the status of conservation of these rocks. The sandstones of Palazzo Ducale belong to the Miocene formation called "Camerino Sandstones", which are related to a turbiditic sedimentary cycle. The Palazzo Ducale lies on this formation. By a clissifi­cative point of view, the "Camerino Sandstones" can be regar­ded as a marly - carbonatic cemented biomicritic calcarenite with cherts, mono - and policrystalline clasts of quartz, feld­spars (plagioclase prevails on K - feldspar), spatic and / or cryptocrystalline calcite and fragments of sedimentary (sand - and limestone) and volcanic (vitrophiric) rock stones. Subordinately, gypsum, halite, chabasite, pyrite, aragonite, bio­tite and muscovite and rare pyroxene and amphibole occur. Phyllosilicates are mainly represented illite, smectite, chlorite, kaolinite and, at a minor extent, serpentine and vermiculite. [...]