Rocks What are Rocks Rocks are a combination

  • Slides: 33
Download presentation
Rocks

Rocks

What are Rocks? Rocks are a combination of minerals that are bonded together in

What are Rocks? Rocks are a combination of minerals that are bonded together in some way. • All rocks are made of minerals – Monomineralic- contain one mineral Polymineralic- contain more than one mineral Rocks are classified into three groups by how they are formed Types of Rocks Igneous Sedimentary Metamorphic

3 types of Rocks Types of Rocks Igneous Sedimentary Igneous Rocks: Form from molten

3 types of Rocks Types of Rocks Igneous Sedimentary Igneous Rocks: Form from molten rock that cools and hardens. • Sedimentary Rocks: Form from sediments (pieces of other rocks) that are cemented together. Rocks are classified by how they form Metamorphic • Metamorphic Rocks: are formed when old rocks change by heat and pressure.

Rock Cycle • Rock must go through melting and solidification to become an igneous

Rock Cycle • Rock must go through melting and solidification to become an igneous rock • Rock must go through weathering and erosion to become sedimentary rock • Rock must go through heat and pressure to become a metamorphic rock

Classification of igneous rocks 2 types Intrusive • Form from magma • Cooled and

Classification of igneous rocks 2 types Intrusive • Form from magma • Cooled and solidified (hardened) slowly deep underground • Large crystal size Extrusive • Form from lava • Cooled and hardened quickly at or near the surface of the earth. • Small or no crystals

Igneous rocks are also formed when volcanoes erupt, causing the magma to rise above

Igneous rocks are also formed when volcanoes erupt, causing the magma to rise above the earth's surface.

Types of igneous rocks • Granite- most abundant igneous rock • Can be made

Types of igneous rocks • Granite- most abundant igneous rock • Can be made up of feldspar, quartz, mica, and hornblende

Obsidian • • Obsidian rocks are igneous rocks that form when lava cools quickly

Obsidian • • Obsidian rocks are igneous rocks that form when lava cools quickly above ground. • Obsidian is actually glass and not a mixture of minerals. The edges of this rock are very sharp.

Pumice • Pumice rocks are igneous rocks which were formed when lava cooled quickly

Pumice • Pumice rocks are igneous rocks which were formed when lava cooled quickly above ground. • This rock is so light, that many pumice rocks will actually float in water. • Pumice is actually a kind of glass and not a mixture of minerals. •

Extrusive Intrusive

Extrusive Intrusive

Igneous Rock ID- Lab #10 Vocab • Texture- refers to the size/appearance of the

Igneous Rock ID- Lab #10 Vocab • Texture- refers to the size/appearance of the mineralscan be glassy, coarse, fine, vesicular • Intrusive- rocks cooled deep underground by magma • Extrusive- rocks cool on or near earth’s surface by lava • Mafic- dark colored rocks that are rich in iron and Mg. Higher density • Felsic- light colored rocks that are rich in elements such as aluminum, silicon. Lower density

II. SEDIMENTARY ROCKS

II. SEDIMENTARY ROCKS

How are they formed? £Fragments of rock get broken down into sediments £Sediments are

How are they formed? £Fragments of rock get broken down into sediments £Sediments are transported, compacted, and cemented into rock 1. ARE USUALLY FORMED IN A WATERY ENVIRONMENT. 2. OFTEN LAYERED 3. ARE THE ONLY ROCKS THAT CONTAIN FOSSILS

Sedimentary Rocks: Are the only type of rocks that contain fossils. Fossil formation http:

Sedimentary Rocks: Are the only type of rocks that contain fossils. Fossil formation http: //www. classzone. com/books/earth_science/terc/conte nt/visualizations/es 2901 page 01. cfm

Clastic Rocks- fragments cemented together sediments inlcude: sand, silt, clay, pebbles, boulders

Clastic Rocks- fragments cemented together sediments inlcude: sand, silt, clay, pebbles, boulders

Chemical rocks (crystalline) result of evaporation • Generally these rocks are formed from one

Chemical rocks (crystalline) result of evaporation • Generally these rocks are formed from one mineral Rock salt (halite) Rock gypsum- made from gypsum

Organic rocks (contain remains of living things) Bituminous coal- fossil fuel Formed from plant

Organic rocks (contain remains of living things) Bituminous coal- fossil fuel Formed from plant remains in Swampy areas- most are millions Of years old Limestone- made from Mineral calcite and Fragments of shells

3. Metamorphic rocks

3. Metamorphic rocks

Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks

Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks. The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change. Heat and pressure causes the minerals to recrystallize, density increases, and the rocks become harder

How are they formed? • Metamorphic rocks are pre-existing rocks that have been changed

How are they formed? • Metamorphic rocks are pre-existing rocks that have been changed by heat and/or pressure without melting. • These pre-existing rocks are called parent rocks

Classification- 2 groups • Foliated • Mineral crystals are aligned, or arranged in bands

Classification- 2 groups • Foliated • Mineral crystals are aligned, or arranged in bands or layers. • Banding: High grade metamorphism. Alternating layers of dark and light minerals. • Non-foliated • Mineral crystals do not have mineral crystals arranged in bands of layers. Example marble and quartzite.

Metamorphism • Regional Metamorphism – Caused by extreme pressure and heat. – Happens over

Metamorphism • Regional Metamorphism – Caused by extreme pressure and heat. – Happens over wide “regions”. • Contact Metamorphism – Caused by contact with extreme heat.

Holey schist!

Holey schist!

Based on the characteristics, what kind of rock is A? B? C? D? E?

Based on the characteristics, what kind of rock is A? B? C? D? E? Write the key word that led you to this conclusion.