Rocks ESPS Hagen

Vocabulary List 1. Rock Cycle 2. Igneous rocks 3. Magma 4. Lava 5. Intrusive rocks 6. Extrusive rocks 7. Metamorphic rocks 8. Sedimentary rocks

The Rock Cycle Rocks form from a mixture of minerals, mineraloids, glass and or organic matter The rock cycle shows how the 3 types of rock form and change The 3 types of rocks are metamorphic, igneous and sedimentary The processes that form and change rocks are: weathering, erosion, compaction, cementation, melting and cooling

The Rock Cycle

Igneous Rocks Igneous rocks form when magma or lava cools and hardens Magma is liquid rock below the Earth’s surface Depths range from 60 to 200km and temperatures reach about 1400°C Lava is liquid rock that flows from volcanoes on the surface of the Earth

Igneous Rocks When magma cools inside the Earth’s surface the rocks are called intrusive rocks These rocks tend to have large mineral grains that you can easily see (like granite) because the magma cools slowly and the minerals have time to group together and form

Common Intrusive Igneous Rocks Granite Diorite Gabbro

Igneous Rocks When lava cool on the Earth’s surface the rocks are called extrusive rocks Because the air is so much cooler on the Earth’s surface extrusive rocks cool very quickly Because they cool so quickly the minerals do not have time to come together and cool you cannot see the different minerals that make up extrusive rocks

Common Extrusive Igneous Rocks Obsidian Pumice Scoria

Classifying Igneous Rocks The first step to classify an igneous rock is to determine if it is intrusive or extrusive The second step to classify an igneous rock is to determine what type of magma or lava it formed from 3 types of magma or lava are: basaltic, andesitic or granitic

Classifying Igneous Rocks Basaltic rocks: they are dense and heavy, dark colored and rich in iron and magnesium (these are common in the Hawaiian Islands) Granitic rocks: they are light colored, have lower density than basaltic rocks and they contain a lot of silicon and oxygen Andesitic rocks: they have mineral combinations between granitic and basaltic Igneous rocks are the most abundant rock on the planet

Metamorphic Rocks Metamorphic rocks undergo change due to intense heat and pressure (but do not melt!) Metamorphic rocks can form from igneous, sedimentary or other metamorphic rocks The heat and pressure come from deep inside the Earth The amount of heat and pressure determine what type of metamorphic rock will form

Common Metamorphic Rocks Slate Gneiss Marble

Classifying Metamorphic Rocks The main way to classify a metamorphic rock is to determine if the rock is foliated or nonfoliated Foliated rocks have flatten parallel bands that are easily separated along the bands Common foliated rocks are slate and gneiss Nonfoliated rocks do no have bands Common nonfoliated rocks are quartzite and marble

Sedimentary Rocks While most of the rocks on Earth are igneous rocks chances are you have seen mostly sedimentary rocks on the surface Sedimentary rocks form when sediments are pressed or cemented together Sediments form from other rocks or even living things that have been broken apart by wind or water These processes are called weathering and erosion

Sedimentary Rocks Sedimentary rocks get packed together by compaction or cementation Compaction occurs by erosion moves sediments to a new location, where they are deposited, over time sediments get piled up and the layers of sediment push down to form a rock

Sedimentary Rocks Cementation occurs when water flows through the sediment and dissolved minerals that naturally form a cement causing the remaining sediment to form a rock Sedimentary rocks often form layers that are easily seen The older rocks are on the bottom and the newer rocks on top These layers can tell the history of the area

Common Sedimentary Rocks Shale Conglomerate Sandstone Siltstone Limestone

Classifying Sedimentary Rocks Sedimentary rocks are mainly identified by the composition of the sediments from the original rocks Sedimentary rocks are classified as: detrital, chemical or organic Detrital rocks are made from fragments of other rocks that have been cemented together (these rocks are called clasitc because of their texture)

Classifying Sedimentary Rocks Detritial rocks are named according the shape and size of the sediments If the sediments are large and round they are called conglomerate rocks, but if they are large and sharp they are called brecca rocks If the sediments are sand size the rock is called sandstone

Classifying Sedimentary Rocks Chemical sedimentary rocks form when minerals are dissolve by water and the water evaporates leaving the rock behind Limestone is formed from ocean water Rock salt is formed from lakes and seas Organic sedimentary rocks from from the remains of living things Coal is an example of a chemical sedimentary rock