2The three types of rocks IgneoussedimentaryMetamorphicAll types of rock are subject to processes that change one rock type into another.
3Igneous Rocks Formed from cooled and solidified magma Intrustive formed from the cooling of magma within the earth’s crustCools and hardens slowlyCoarse grained- forms large, well-developed crystalsExtrusivemelted rock that hardens on the earth’s surfaceLava cools rapidlyfine grained rocks
5Composition of Igneous Rocks Felsic- Rocks in the granite familyLight coloredHigh silica contentLow magnesium and iron contentMafic- Rocks in the basalt familydark coloredlower silica contenthigh mg and fe contentAndesitic - Medium SilicaGreen, grey, or brown
6Sedimentary Rocksrock formed from the debris of both other rocks and living matter.90% of the earth’s crust is made from igneous rock, but 75% of the world’s land surface is covered with thin layers of debris or sediments.These sediments settle on the beds of oceans, lakes, and rivers, and recompacted over millions of years to form sedimentary rock.
7How are Sedimentary Rocks Formed? DIAGENESIS-the process that turns loose sediments into rock COMPACTION-the slow squeezing of sediment to form hard rockCEMENTATION-The binding together of compacted sediments by chemicals like calcite, silica, and iron
93 types of Sedimentary Rock: CLASTIC- form from rock fragments weathered and eroded by glaciers, wind, rivers, and waves.ORGANIC- rock made from the remains of plants and animalsCHEMICAL- rock made from chemicals dissolved in water
10BEDDING PLANE-a boundary between one layer of sedimentary rock and another
11Metamorphic Rocksformed from other rocks as a result of intense heat, pressure, and chemical processesmost form deep beneath the surface of the earthformed from existing igneous, sedimentary, or metamorphic rock
12Types of metamorphic formation: Contact metamorphism:when hot magma pushes through existing rock, changing the structure and composition of the rock. Only rocks near the magma are changed.Regional metamorphism:movement of one tectonic plate against another causes heat and pressure, affecting rocks over an area of many thousands of kilometers
13Types of metamorphic rocks: Foliated:show visible parallel bands of minerals ex: slate, schist Unfoliated:no bands of crystals ex: quartzite, marble