3 A. Early Earth 1. Early surface was a violent place 2. Full of molten lava and no atmosphere; ittook time for Earth to cool and appear as it does now.3. As surface cooled, patches of solid minerals began to form.4. These lightweight minerals formed the first rocks.
4 A. Minerals All rocks composed of minerals Mineral-natural, inorganic solidInorganic – was never aliveUsually composed of crystals95% rocks made up of minerals
5 B. 3 Types of Rocks Rocks – a group of minerals bound together. Igneous - Most of Earth’s crust is made of igneous rockSedimentary - The most common rock in uppermost portion of Earth’s crustMetamorphic – near volcanoes and plate boundaries
6 C. Igneous Rock Rock formed from cooled and hardened magma or lava Two TypesExtrusive – cools quickly on Earth’s surfaceUsually out of volcano or crack in Earth’s surfaceIntrusive – cools slowly while trapped beneath Earth’s surfaceThe surrounding hard rock acts like a blanket, allowing it to cool slowlyLava cools quickly – few crystalsMagma cools slowly – lots of crystals
11 D. Sedimentary Rocks Rocks broken down by weathering and erosion Pieces accumulate and are compressed and cemented together to form sedimentary rockPieces can contain fossils (plant or animal) **ONLY ONES!!Sediment must be compressed or cemented together.
12 E. Sedimentary Formed in 2 ways 1. Rocks made of broken pieces (clasts) of other rocks.Pieces of rock appear to be glued together.2. Pieces/fine grains brought together by:a. Compaction - is a process that squeezes, or compacts sediments.b. Cementation -takes place when sediments are glued together by tiny minerals.
17 G. Metamorphic rockMetamorphic – preexisting rocks that are transformed by high temperature and/or pressure; their properties change.Metamorphism often gives rock a distinctive banding patternTheir unique colors and patterns make them ideal for sculptures.
18 G. Metamorphic cont. 3. Formed in 2 ways: a. heat alone caused by hot magma of igneous intrusions.b. both heat and pressure: can occur over entire region4. Rock undergoes chemical change over millions of years without melting5. Fossils are destroyed by heat and pressure.
25 I. Rock cycleExplains the sequence of events in which rocks are weathered, melted, altered, and formed.Geological processes of the earth’s crust recycling one type of rock into another.Rock formation occurs SLOWLY, often over thousands of years.
27 SEDIMENTARY ROCK SEDIMENT = SAND METAMORPHIC ROCK IGNEOUS ROCKS MagmaCools and hardensWeather and ErosionCompaction and CementationHeat and PressureSEDIMENTARY ROCKSEDIMENT = SANDMETAMORPHIC ROCKIGNEOUS ROCKSMELTING