Minerals & Rock Unit Notes 7th Grade Science

Rocks Are divided into 3 groups based on how they were formed Sedimentary Metamorphic Igneous Are made of one or more minerals

Continually changed by processes such as Weathering, Erosion Do not stay the same Continually changed by processes such as Weathering, Erosion Compaction, Cementation, Melting, and Cooling.                                                                           

Rocks can change to and from the 3 types The Rock Cycle Earth materials change back and forth among the different types of rocks.

Weathering, Erosion, Deposition, Compaction, Cementation Igneous (Granite #11) Melting, Solidification Weathering, Erosion, Deposition Compaction, Cementation Recrystallization Melting, Solidification Recrystallization Metamorphic (Gneiss #14) Sedimentary (Sandstone #6) Weathering, Erosion, Deposition, Compaction, Cementation

Processes that form Sedimentary Rock Weathering: the breaking down of the Earth’s material by natural processes (Water, Wind, Ice, Chemicals, etc.) into smaller pieces or sediments Erosion: weathered rock and soil particles are moved from place to place Deposition: weathered sediments are laid down in a new location creating new landforms or rocks Compaction: heavy sediments press down on the layers beneath Cementation: dissolved minerals flow between the sediments and cement them together Processes that form Sedimentary Rock

Processes that form Igneous & Metamorphic Rock Melting: caused by heat and pressure around the rock to form magma Solidification: magma cools and hardens Recrystallization: while cooling, rock can develop crystals, depending on conditions Processes that form Igneous & Metamorphic Rock

Complete the following: Turn in your Rock Cycle Directed Reading & Earthquake/Volcano Test Corrections Get the 2 Directed Readings from the table Have something to write with Clear off your table

Complete the following: Turn in your Rock Cycle Directed Reading, Comic Strip & Earthquake/Volcano Test Corrections Get the Igneous Rock Directed Reading from the table Get out your Minerals & Rocks Notes Have something to write with Clear off your table

Igneous Igneous is Latin for “born of fire” Formed from cooling magma or lava

Forms when magma cools and solidifies Some reaches the surface of earth before cooling, other cools under the surface

Intrusive Extrusive Form below ground from magma (Example: Granite) Form below ground from magma Usually has coarse crystals (grains) from cooling slowly Some have large and small crystals Form above ground from lava Usually have small or no crystals from cooling quickly Extrusive (Examples: Pumice & Obsidian)

Into the Bedrock On top (Exit) intrusive extrusive (crystals) (no crystals)

Bedrock                    Magma!

Complete the following: Get out your Minerals & Rocks Notes Get the Paper from the table Have a Textbook Have something to write with

Igneous!

But then the EARTH’S elements Will not leave the ROCK alone!

Ice Wind Water ice wind water

They break up the stone

One way Sedimentary Rock can be formed Deposit & Compress the Sediments One way Sedimentary Rock can be formed That ROCK changed again!

Sedimentary Rock Formed from sediments (rock fragments, mineral grains, animal and plant remains) that are pressed or cemented together or when sediments precipitates out of a solution. Sediments are moved by wind, water, ice, or gravity.

The heavy sediments press down on the layers beneath (Compaction) Water or wind breaks down (Weathering), moves (Erosion), and deposits sediment (Deposition) The heavy sediments press down on the layers beneath (Compaction) Dissolved minerals flow between the sediments and cement them together (Cementation)                                         

Sedimentary Rocks & Fossils Deposited sedimentary rocks form horizontal layers called STRATA. Process of arranging sedimentary rocks into layers is STRATIFICATION Scientist know that the layers and fossils on top are YOUNGER than the fossils in lower layers  Law of Superposition                                         

Types of Sedimentary Rocks Clastic: made of broken pieces of other rocks. Organic: remains of once living plants and animals are deposited in thick layers called fossils Chemical: minerals dissolved in lakes, seas, or underground water Limestone made when calcite precipitates from sea water Rock salt made from evaporation of sea waters Types of Sedimentary Rocks

The Rock Cycle Igneous Metamorphic ? Sedimentary

The Rock Cycle Igneous Metamorphic kinda melted squished Sedimentary

Bands (can) Form                                                                                     Metamorphic means “changed” Metamorphic!

Metamorphic Rocks Rocks changed due to intense heat and high pressure “Meta-” means “changed” and “-morphosis” means “shape” in Greek Igneous, Sedimentary and other Metamorphic rocks can change to become Metamorphic rocks

How Metamorphic Rocks Change Pressure from overlying rock layers High heat, but not enough to melt the rock Rocks may be flattened or bent or atoms may be exchanged to form new materials. Think of metamorphic rocks as a squished peanut butter and jelly sandwich in your lunch. How Metamorphic Rocks Change m

Types of Metamorphic Rock Foliated Has visible parallel layers or bands you can see Example: Gneiss formed from rearrangement of minerals in Granite into bands Not layered & no bands are formed Example: Marble formed from Limestone Non-Foliated

The Rock Cycle Igneous metamorphic Sedimentary

The Rock Cycle                                                                                                         

always changing…

Volcano Roots here! Youngest Rocks Here ! Oldest Rocks Here !