Chapter 4 Mrs. Veurink’s Earth Science The Rock Cycle Chapter 4 Mrs. Veurink’s Earth Science

What is a ROCK? A rock is a naturally occurring solid mixture of one or more minerals and organic matter

Texture: the size, shape, and pattern of the rock’s grain. Classifying Rocks When classifying a rock sample geologists observe the rock’s color and texture and determine its mineral composition. Texture: the size, shape, and pattern of the rock’s grain. Color: the apparent color of the rock, on the inside and the outside. Mineral composition: The minerals that make up the different parts of a rock.

Three different rock Types:

Igneous Rocks "Fire Rock" Igneous rock forms when magma cools and makes crystals. Magma is a hot liquid made of melted minerals. When magma pours onto the earth’s surface it is called lava. The minerals can form crystals when they cool. Igneous rock can form underground, where the magma cools slowly. Or, igneous rock can form above ground, where the magma cools quickly.

2 Types of Igneous Rocks INTRUSIVE IGNEOUS ROCKS – When igneous rocks are formed by magma that cools BENEATH Earth’s surface. example-Granite EXTUSIVE IGNEOUS ROCKS – When igneous rocks are formed by LAVA ON Earth’s surface. example- basalt

Igneous Rock Examples Basalt Granite

Sedimentary Rocks Sedimentary rocks form from particles deposited by water and wind If you have ever walked along a beach (which I am sure you have) you may have noticed tiny sand grains, mud, and pebbles. These are some sediments that eventually form into sedimentary rocks

Three types of Sedimentary Rock Clastic- made of fragments of rocks cemented together by a mineral such as calcite or quartz. Example - Conglomerate Chemical- forms from solutions of dissolved minerals and water. Example –Halite Organic- forms from the remains or fossils of animals that once lived in the ocean. Example- Fossiliferous limestone

Sedimentary Rock Pics Conglomerate Halite Fossiliferous Limestone

Sedimentary Rocks : Weathering or Erosion Destructive forces are constantly breaking up and wearing away all the rocks on Earth’s surface The forces include heat and cold, rain, waves, and grinding ice Erosion occurs when running water or wind loosens and carry away the fragments of rock. This forms- SEDIMENT

Sedimentary Rocks: Deposition Eventually, the moving water or wind slows and deposits the sediment. If water is carrying the sediment, rock fragments and other materials sink to the bottom of a lake or ocean. In addition to particles of rock, sediment may include shells, bones, leaves, stems, and other remains of living things. These may become fossils.

Sedimentary Rocks: Compaction Compaction is the process that presses sediments together. Year after year more sediment falls on top, creating new layers. This is called stratification. The weight of the layers further compacts the sediments, squeezing them tightly together. The layers often remain visible in the sedimentary rock and are called STRATA.

Sedimentary Rocks: Cementation  While compaction is taking place, the minerals in the rock slowly dissolve in the water. The dissolved minerals seep into the spaces between particles of sediment. Cementation is the process in which dissolved minerals crystallize and glue particles of sediment together. This finally forms the sedimentary rock. It often takes millions of years for compaction and cementation to transform loose sediments into solid sedimentary rock.

Sedimentary Transformations Erosion (Weathering) and Deposition: water or wind deposits sediments Compaction: The heavy sediments press down on the layers beneath Cementation: Dissolved minerals flow between the particles and cement them together

Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks. How do sedimentary and igneous rocks change? The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change. Metamorphic Rocks

Metamorphic Rock Pics There are two types of Metamorphic Rocks Foliated- mineral grains are arranged in bands Nonfoliated- grains not arranged in bands Gneiss Slate

Bet Cha’ Weren’t Expecting A…. POP QUIZ!!!!!* Which type of rock has been formed by magma or lava? What are the three types of rock? What do we classify rocks by? How do sedimentary rocks form (in order)? Metamorphic rocks are rocks that have ?(fill in the blank) What is the process in which sedimentary rocks are arranged in layers? What does “ignis” mean in the word igneous? *Answers are on next slide!

ANSWERS!!!! Igneous, Sedimentary, and Metamorphic Igneous Texture, Color, and Mineral Composition Erosion, Deposition, Compaction, Cementation Morphed Stratification “ignis” means FIRE

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