I. Minerals and Rocks

A. Early Earth 1. Early surface was a violent place 2. Full of molten lava and no atmosphere; it took 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.

A. Minerals All rocks composed of minerals Mineral-natural, inorganic solid Inorganic – was never alive Usually composed of crystals 95% rocks made up of minerals

B. 3 Types of Rocks Rocks – a group of minerals bound together. Igneous - Most of Earth’s crust is made of igneous rock Sedimentary - The most common rock in uppermost portion of Earth’s crust Metamorphic – near volcanoes and plate boundaries

C. Igneous Rock Rock formed from cooled and hardened magma or lava Two Types Extrusive – cools quickly on Earth’s surface Usually out of volcano or crack in Earth’s surface Intrusive – cools slowly while trapped beneath Earth’s surface The surrounding hard rock acts like a blanket, allowing it to cool slowly Lava cools quickly – few crystals Magma cools slowly – lots of crystals

Igneous Rocks

What type of igneous is pictured below?

C.Igneous rocks cont. Basalt – extrusive Obsidian - extrusive Granite – intrusive*

Igneous movie

D. Sedimentary Rocks Rocks broken down by weathering and erosion Pieces accumulate and are compressed and cemented together to form sedimentary rock Pieces can contain fossils (plant or animal) **ONLY ONES!! Sediment must be compressed or cemented together.

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.

F. Common sedimentary rocks Conglomerate – pebbles glued together Sandstone - sand Mudstone - mud Shale – mudstone that breaks apart into layers Limestone – fossils from sea

G. Metamorphic rock Metamorphic – preexisting rocks that are transformed by high temperature and/or pressure; their properties change. Metamorphism often gives rock a distinctive banding pattern Their unique colors and patterns make them ideal for sculptures.

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 region 4. Rock undergoes chemical change over millions of years without melting 5. Fossils are destroyed by heat and pressure.

What type of metamorphism?

What type of metamorphism?

H. Common Metamorphic rocks Marble –comes from limestone Slate – comes from shale

Metamorphic rock

I. Rock cycle Explains 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.

SEDIMENTARY ROCK SEDIMENT = SAND METAMORPHIC ROCK IGNEOUS ROCKS Magma Cools and hardens Weather and Erosion Compaction and Cementation Heat and Pressure SEDIMENTARY ROCK SEDIMENT = SAND METAMORPHIC ROCK IGNEOUS ROCKS MELTING

Convection currents

Granite cliffs

Devils tower

Importance of Rocks and Minerals

Metamorphic movie

Rock Cycle movie