Presentation on theme: "The Rock Cycle NASA videovideo. The three types of rocks – Igneous – sedimentary – Metamorphic All types of rock are subject to processes that change."— Presentation transcript:
The Rock Cycle NASA videovideo
The three types of rocks – Igneous – sedimentary – Metamorphic All types of rock are subject to processes that change one rock type into another.
Igneous Rocks Formed from cooled and solidified magma – Intrustive formed from the cooling of magma within the earth’s crust Cools and hardens slowly Coarse grained- forms large, well-developed crystals – Extrusive melted rock that hardens on the earth’s surface Lava cools rapidly fine grained rocks
Composition of Igneous Rocks Felsic- Rocks in the granite family – Light colored – High silica content – Low magnesium and iron content Mafic- Rocks in the basalt family – dark colored – lower silica content – high mg and fe content Andesitic - Medium Silica – Green, grey, or brown
Sedimentary Rocks rock 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.
How are Sedimentary Rocks Formed? DIAGENESIS- – the process that turns loose sediments into rock – COMPACTION- the slow squeezing of sediment to form hard rock – CEMENTATION- The binding together of compacted sediments by chemicals like calcite, silica, and iron
3 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 animals – CHEMICAL- rock made from chemicals dissolved in water
BEDDING PLANE- a boundary between one layer of sedimentary rock and another
Metamorphic Rocks formed from other rocks as a result of intense heat, pressure, and chemical processes – most form deep beneath the surface of the earth – formed from existing igneous, sedimentary, or metamorphic rock
Types 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
Types of metamorphic rocks: Foliated: – show visible parallel bands of minerals ex: slate, schist Unfoliated: – no bands of crystals ex: quartzite, marble