Lesson 8- Minerals and Rocks

From Last Class… At this point you should have completed: Title Page KWL Sheet Part 1: Task 1 (Earth’s Crust); Task 2 (Pangea); Part 2: Task 3 (Map of Earthquakes, Volcanoes, Mountains); Task 4 (Types of Mountains); Task 5 (Volcanoes) Part 3: Task 6 (Soil Layers); Task 7 (6 Types of Erosion)

From Last Class… Part 1, 2 and 3 SHOULD be completed by now Option to take home folder at end of class again TOMORROW Part 4/FINAL due date is FRIDAY JUNE 15th at 3:15PM! NO LATER! NO EXCEPTIONS! NO EXTENSIONS!

Earth’s Crust Booklet Part 4 Part 4 will look at Rocks and Minerals, please complete the following tasks on looseleaf and place them in your duotang Task 8: What is the difference between Rocks and Minerals? List at least 2 similarities and 2 differences between rocks and minerals, and give 5 examples of each. Task 9: What are the different types of Rock? Use your textbook to define the terms Sediment, Sedimentary Rock, Metamorphic Rock and Igneous Rock Task 10: Rock Cycle On the sheet provided in your duotang, label and explain the rock cycle. You must include igneous, metamorphic and sedimentary rock, sediment and MAGMA

Rocks vs Minerals A mineral is solid inorganic material of the Earth that has both a known chemical composition and a crystalline structure that is unique to that mineral Pure natural building blocks of rock Ex: Gold, iron, diamonds, Hematite, Quartz All minerals are pure crystals (geometric shapes made up of a repeating pattern or lattice) A rock is a solid aggregate of one or more minerals that have been cohesively brought together by a rock-forming process.

Minerals Elements are chemically combined to form minerals

A crystal is composed of a structural unit that is repeated in three dimensions. This is the basic structural unit of a crystal of sodium chloride, the mineral halite.

The structural unit for a crystal of table salt, sodium chloride, is cubic, as you can see in the individual grains.

These quartz crystals are hexagonal prisms.

Rocks Minerals are physically combined to form rocks 3 types: Igneous, Metamorphic, Sedimentary

Igneous Rock Igneous= Latin for fire; rocks born of fire! Intrusive igneous rock Formed when magma cools deep within the Earth’s surface Cools very slowly as it is in contact with molten rock. Produces course-grained igneous rock. Extrusive igneous rock Magma that cools above the Earth’s surface. Produces fine-grained igneous rocks. This rapid cooling does not allow time for crystals to form.

Igneous Rock Pumice: an example of igneous rock that was ejected during an explosive volcanic eruption; has lots of air pockets caused by gas being trapped in the rock Cinder: another igneous rock formed from eruption from a volcano, larger bubbles

Igneous Rock Obsidian: which has the same chemical composition as the granite. Obsidian has a different texture because it does not have crystals and is a volcanic glass.

Igneous Rock Basalt: volcanic rock derived from earth’s upper mantle. Formed from slow flow magma, often from oceanic volcanoes

Sedimentary Rock Sedimentary Rocks Form from material from previously existing rock (SEDIMENTS) Material is provided by weathering of previously existing rock Slow accumulation of materials that are compressed and cemented together over time Sediments Weathered rock materials Dissolved rock materials

Compaction Cementation As sediments are laid down grain by grain, the mass becomes greater. The increasing mass of the sediment layer above creates pressure on the layers below. Eventually this pressure becomes great enough to compact the existing layers into a cohesive rock layer. Cementation After, or during, the compaction process, the spaces between the sediment particles become filled with a chemical deposit. This deposit holds the compacted layers into a cohesive mass of sedimentary rock.

(A)In compaction, the sediment grains are packed more tightly together, often by overlying sediments, as represented by the bricks. (B) In cementation, fluids contain dissolved minerals that fill in the space between the grains, cementing them together into a rigid, solid mass.

This is a sample of sandstone, a sedimentary rock that formed from sand grains in a matrix of very fine-grained silt, clay, or other materials.

This is a sample of limestone, a sedimentary rock made of calcium carbonate that formed under water directly or indirectly from the actions of plants and animals. This fine-grained limestone formed indirectly from the remains of tiny marine organisms.

3 Types of Sedimentary Rocks Clastic: formed from eroded fragments of existing rocks (sand, silt or clay) that have been compressed and cemented together Chemical: formed from chemicals that were dissolved in water but have settled out and crystallized into rock Biological: Organic rock that contains compressed organic matter.

Metamorphic Rock Rocks that have changed forms rocks that were once sedimentary, igneous or even other metamorphic Metamorphic Rocks Rocks changed by heat, pressure, or hot solutions due to: Movement of the Earth’s crust Heat generated by intrusion of hot magma Pressure can change rock by flattening, deforming, or realigning mineral grains. Foliation When the pressure on flat crystal flakes tends to align the flakes into parallel sheets. Gives the rock the property of breaking along the planes between the aligned mineral grains in what is known as rock cleavage.

Metamorphic rock transformation Granite Gneiss (due to heat and temperature) Sandstone Quartzite Shale slate (compressed deep beneath earth surface) LimestoneMarble (high pressure) Igneous/sedimentary Schist (compressed)

This is a sample of marble, a coarse-grained metamorphic rock with interlocking calcite crystals.

This banded metamorphic rock is very old; at an age of 3 This banded metamorphic rock is very old; at an age of 3.8 billion years, it is probably among the oldest rocks on the surface of the earth.