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ROCKS Granitic rock Duero River • Earth and Planets are built on rocks • Rocks are formed on minerals. minerals Actually every one is a system in which the chemical components are organized i d in i different diff phases‐ h the minerals ‐ as the answer to the physicochemical conditions‐ the factors ‐ that were present at their generation. • The phases are distributed following a particular ti l geometric t i arrangementt ‐ structure, t t microstructure – that is also the consequence of physicochemical conditions . • To be used in building they must be able of being cut in blocks and slices, slices polished, carved, etc. • Depending p g on their composition p and structure they show different mechanical properties like charge resistance, resistance hardness, etc. • And different behavior when they are cut, t abraded b d d and d suffer ff weathering, th i or anyy kind of chemical alteration. • Therefore,, theyy are three bigg ggroups p of rocks depending on their minerals and structure, that are consequence of their origin •IGNEOUS •SEDIMENTARY •METAMORPHIC METAMORPHIC Rocks cycle http:www.minsocam.org Rocks classification Rocks classification • There are different criterion for classification: • The more general is based in the quantity of The more general is based in the quantity of the forming minerals that are organized as • Primary: Pi – Essential: more than 5% in volume – Accessory: less than 5% in volume • Secondary: formed after any primary • This general system is mainly working for igneous g y y g g rocks IGNEOUS • They are formed by solidification of a melt, mainlyy silicate made, rarelyy carbonate, formed in the interior of the Earth, in the Mantle or the Crust : ‐VOLCANIC‐ they solidify on the terrestrial surface y y ‐PLUTONIC‐ they solidify in the interior IGNEOUS ‐ ‐VOLCANIC‐ they use to be porous, having isotropic structure, or less penetrative orientation: ‐massive‐ basalt, andesite, rhyolite, trachyte, etc. fragmentary they can consolidate forming tuffs ‐fragmentary‐ ‐PLUTONIC‐ PLUTONIC massive, i non porous, they th use to t be b isotropic although they can also be oriented : gabbro, diorite, granite, syenite, monzonite, anorthosite, etc. Classification of Igneous Rocks volcanic I.U.G.S.-UNESCO plutonic Massif volcanic rocks Lava flows Basalt Fragmentary volcanic rocks Tuffs (ignimbrites) Massif ass volcanic o ca c rocks oc s Trachyte Plutonic Granite Guisando’s Bulls-Ávila Plutonic Vilvestre Granite Bernardos phyllite Mº de El Escorial Magmatic foliation phenocryst porphyritic porphyritic Granites: different types In general, the color is darker in the sense of the arrow Plutonic G bb Di it Gabbro-Diorite SEDIMENTARY • They are originated on the earth surface, and consolidate at moderate deepness by burial, reaching up about 200 ºC • They use to be porous, there are two big groups: ‐Terrigenous clastic rocks ‐Chemical and organic origin SEDIMENTARY • TTerrigenous i clastic– l i They Th are formed f d through h h the h breaking of any previous rock. The fragments, clasts, accumulate l and d have h i interstitial i i l material i l like lik matrix i and cement. They are buried and compacted during a process called ll d diagenesis di i . • The classification is made following the size of clasts : ‐ conglomerates, sandstones, limolites ‐ 2mm 0,0625mm • CHEMICAL and ORGANIC ORIGIN – due to chemical precipitation and biological activity: ‐ limestones, dolostones, gypsum, silexites, etc Conglomerate clast cement Casa de las Conchas Salamanca Sandstone conglomerate granite it Sergilla-Syria, first century A.D. limestone Limestone blocks Silex nodules Al Russafah-Syria outcrop Gypsum METAMORPHIC • They result from the transformation f i off any previous rock (protolith), that h must be b adapted d d to new physicochemical conditions di i ‐Pressure P and d Temperature –that are ti l ti operating along a time (PTt) Met. Facies t P Regional Trayectory Contact Trayectory T METAMORPHIC • Non porous • They are classified after their structure: Th l ifi d ft th i t t – Isotropic‐ “felses”, granofelses: marble (carbonate fels), quartzite, hornfels, granulite, eclogite, etc. – Oriented‐ slate, phyllite, schist, gneiss, migmatite, ,p y , ,g , g , Several other names are based in mineral composition having any structure: having any structure : amphibolite, serpentinite, etc – Usually Usually the structural name is combined with the names of the minerals that the structural name is combined with the names of the minerals that form the rock, except several particular terms used by tradition – When the protolith is identified , the name can be the one of the protolith with the prefix “meta” the prefix meta microstructures Isotropic -marble Oriented-schist Quartzite chozo In situ Slate-phyillite Schist G i Gneiss Migmatite Foliated Amphibolite schist Marble Macael-Spain carbonate veins Serpentinite Tessellated pavement-Carranque (Toledo) IV Century A.D. Natural rolling stones Philip of Macedonia Palace in PellaGreece ̴ 300 y. B C basalt limestone outcrop Crak des Chevaliers -Syria granite columns Baalbek-Lebanon limestone Palace in Damask-Rocks having different colors END
