recrystallised limestone for metamorphic action. If the original were impure limestones, in addition to calcite are also formed accessory minerals, especially calcium silicate. With increasing amounts of these minerals in the marbles pass calcefiri.
MELAFIRI
paleovulcaniche basaltic rocks, previous to the Tertiary age. The primary cavity of the rock are usually covered with quartz, chalcedony, chlorite and zeolites. The most recent similar rocks are basalts.
Metasco
schist, migmatite, and other metamorphic rocks that you do not recognize the original rock, embedded in metamorphic rocks derived from sedimentary rocks surely (Paraskevi) or eruptive (ortoscisti).
mica
generally quartz mica schists, Regional metamorphism of medium and high grade, derived from clay rocks, represent a more advanced degree of metamorphism of the phyllites, schistose texture are very clear. For the mineral characteristic stand with an adjective: garnetiferous mica, sillimanitici, amphibolites, graphite, etc..
migmatite rocks consist of a mixture of one part of metamorphic rocks and granite on one side or aplitica.
Milone
Rocks rnetamorfismo expatriation, having undergone deeper changes than those of cataclasiti. The composizione mineralogica è varia, dipendendo dalle rocce attraversate dalla zona di frattura in cui esse si formano.
MONZONITI
Rocce intrusive a struttura ipidiomorfa, caratterizzate da feldspato potassico e plagioclasio più o meno nella stessa quantità, da pirosseni, biotite e anfiboli.
NEFELINITI
Rocce filoniane e effusive laviche, ultrabasiche, prive di feldspati, con nefelina e augite.
NORITI
Gabbri a plagioclasi e pirosseno rombico predominanti: si distinguono inoltre noriti oliviniche con olivina; raramente le noriti non oliviniche possono contenere piccole quantità di quarzo (noriti quarzifere).
Ophiolites
Association of igneous and metamorphic rocks (diabase, Spilia, gabbro, serpentine, prasina, amphibolites) derived from basic magmas.
Obsidian Volcanic rocks consisting essentially of glass (silica) blackish not crystallized because of the rapid cooling of magma.
Pegmatite
intrusive rocks, quartz-feldspar is characterized by large crystals. It is often rich in particular minerals, which are formed in the pegmatitic phase of the consolidation of magma, when it is enriched in volatile components and non-fixed elements in crystals of minerals formed.
PERIDOT
Ultrabasic intrusive rocks a fully crystalline structure, composed primarily of olivine and, subject, of pyroxene. When they contain biotite or amphibole are characterized by the adjective characteristic of the mineral mica in peridotite, amphibolite etc..
picrate
effusive ultrabasic rocks rich in olivine, pyroxene with minor amounts of biotite and amphibole with; corresponding effusive of peridotites, some of duniti.
PORFIDI
structure in porphyritic effusive rocks with phenocrysts of potassium feldspar, plagioclase, quartz. We distinguish quartz porphyry and quartz. The quartz porphyry correspond to composition a rhyolite-daciti, quartz or non ortofiri to trachyte. Since the acid magma is viscous and their lavas do not expand easily, the vast expansion in quartz porphyry are interpreted as ignimbrites from the genetic point of view. The term porphyry is more properly used to indicate subvulcaniche in granitic rocks, granodiorite, syenitic and nepheline, and is defined by the adjective corresponding composition of the rock (eg granite porphyry).
PORPHYRIA
Rocks subvulcaniche a porphyritic structure,: neutral or neutral-acid composition corresponding to quartz diorite, diorite, monzonite.
prasina
Metamorphic rocks of low and medium grade sodium chlorite consist of plagioclase, with amphibole, epidotes and other minerals, the texture is shale, more or less pronounced, often peek for the larger crystals of plagioclase.
QUARTZITES
massive metamorphic rocks rich in quartz, usually derived from the recrystallization of siltstones (sedimentary rock similar to sandstone, but with smaller grains).
RIOLO
acidic effusive rocks glass or microcrystalline structure, composition similar to granite. They consist mainly of quartz, potassium feldspar, plagioclase and lesser amounts of biotite. The alkaline rhyolites are richer in alkali feldspar, alkali granites of similar composition. The rhyolites are also called Lipari.
SCHISTE
schistose metamorphic rock texture. The crystalline schists are rocks in the narrow sense of regional metamorphism of medium-and low-grade, rich in lamellar crystals of mica or acicular amphibole with garnet or pyroxene, feldspar, quartz and other silicates, often macrocristallini. They are divided into strips or "sheets" to similar mineralogical composition. Is derived from sedimentary rocks that erupts.
SERPENTINE
igneous or metamorphic rocks Polymorph to ultrabasic composition, consisting mainly of serpentine (chrysotile, antigorite) and other Mg silicates.
SIENA
Intrusive rocks to alkali feldspar, sodium or potassium, in less femici plagioclase and minerals: pyroxene, amphibole, possibly biotite.
skarn rocks of contact metamorphism usually derived by limestone and dolomite, are enriched in Fe, Mg, Si, AI, ferriferi with garnets and other minerals that can form deposits utili.Nella next page, garnet and muscovite mica ( recognized by the dress laminated) in a pegmatitic rock.
SPILIA
effusive rocks are rich in sodium, basic, acid plagioclase (albite), chlorite, epidotes, and altri minerali.
TEFRITI
Rocce effusive laviche alcaline a plagioclasi, feldspatoidi, pirosseni.
TERALITI
Rocce intrusive caratterizzate dall'associazione di plagioclasio, feldspatoidi in forte percentuale, uno o più minerali femici abbondanti, tra cui olivina.
TRACHITI
Rocce effusive laviche acide alcaline, generalmente a struttura porfirica, caratterizzate da feldspato potassico (sanidino), plagioclasi in minor quantità, e minerali femici.
TUFI
Rocce derivate dall'accumulo dei proietti vulcanici (ceneri e lapilli) consolidati. La loro composizione è molto variabile. Possono essersi formate sia in ambiente subaereo sia sottomarino.
VEDI ANCHE ...
ROCCE _ A - B - C - D - E
ROCCE _ F - G - H - I - K - L
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