ROCKS

Rock Vocabulary Sediment Sediment Rock cycle Rock cycle Weathering Weathering Stratification Stratification Igneous rock Igneous rock Sedimentary rock Sedimentary rock Metamorphic rock Metamorphic rock Cementation Cementation Porphyritic texture Intrusive igneous rock Extrusive igneous rock Conglomerate Fossil Ripple mark (look in chapter in sedimentary rock section)

What is a rock?

Maybe made of entirely one mineral or several minerals. Maybe made of entirely one mineral or several minerals. May contain organic matter (composed of living material, usually carbon based) May contain organic matter (composed of living material, usually carbon based) Rocks containing different combinations of the same minerals are different. Rocks containing different combinations of the same minerals are different.

Forms of the same mineral Example: Carbon may be found as a lump of coal or as a diamond. Quite different! COAL DIAMOND

Types of Rocks What are the three classes of rocks? What are the three classes of rocks?

Types of Rocks What are the three classes of rocks? 1. Igneous Rocks 2. Sedimentary Rocks 3. Metamorphic Rocks

Igneous Rocks Name comes from the Latin word “ignis” meaning from fire. Name comes from the Latin word “ignis” meaning from fire. Formed when super hot magma or lava cools. Formed when super hot magma or lava cools. There are seven different classes based on chemical composition of the igneous rock. There are seven different classes based on chemical composition of the igneous rock.

Types of Igneous Rocks As magma moves quickly from the super hot conditions of the Earth to the much cooler surface and becomes lava, it solidifies quickly As magma moves quickly from the super hot conditions of the Earth to the much cooler surface and becomes lava, it solidifies quickly This rock is called extrusive igneous rock This rock is called extrusive igneous rock Fine-grained rocks. Fine-grained rocks. Ex. basalt and rhyolite david-amador.com geology.com

Types of Igneous Rocks Intrusive igneous rock forms when pockets of magma are trapped below the earth’s surface and cool slowly Intrusive igneous rock forms when pockets of magma are trapped below the earth’s surface and cool slowly The magma cools much slower and therefore forms larger crystals. The magma cools much slower and therefore forms larger crystals. Larger crystals give these rocks a rough texture Larger crystals give these rocks a rough texture Ex. granite Mount Rushmore is carved from granite in the Black Hills of South Dakota.

Igneous Rock The best known igneous rock is granite. It is composed almost entirely of feldspar and quartz

Sedimentary Rocks All sedimentary rocks are made of materials called sediments deposited by a particular force or process. All sedimentary rocks are made of materials called sediments deposited by a particular force or process. Those sediments become cemented or compacted together, over time forming a solid rock Those sediments become cemented or compacted together, over time forming a solid rock Uluru (Ayers Rock) in Australia, the world's largest monolith, is made of sandstone.

Types of Sediments Tiny grains of sand Tiny grains of sand Broken pieces of rock along the bottom of a stream Broken pieces of rock along the bottom of a stream Fragments of seashells Fragments of seashells Layers of mud Layers of mud Organic matter (plant and animal remains) Organic matter (plant and animal remains)

Sediments and Sedimentary Rocks Gravity, water, or wind carries them to a destination. Gravity, water, or wind carries them to a destination. Sediments deposit in layers. ( strata=layers of sediment) Sediments deposit in layers. ( strata=layers of sediment) Loosely deposited sediment becomes a rock through compaction or cementation. Loosely deposited sediment becomes a rock through compaction or cementation. Compaction: sediments squeezed together by gravity/pressure. Cementation: sediments glued together by minerals deposited by water.

Sedimentary Rock The most common sedimentary rock is limestone. Develops from living remains (shells, mollusks) Coal is another example of rock derived from organic remains

Sedimentary Rock Often preserve some characteristics from which they were formed. Ripple marks formed in the sand will appear in the rock formed from the sand deposits. Ripple marks formed in the sand by wind

Sedimentary Rocks The source of most fossil remains. The source of most fossil remains. The age of a rock can be determined by studying the fossils within it. The age of a rock can be determined by studying the fossils within it. Fossilized Leaves

Sedimentary Rocks The color of the sedimentary rock also gives us a clue about its chemical composition The color of the sedimentary rock also gives us a clue about its chemical composition The red and pink bands in the Grand Canyon exhibit the iron found in the sediment. The red and pink bands in the Grand Canyon exhibit the iron found in the sediment.

Sedimentary Rocks: Location Sedimentary rocks cover almost all of the ocean floor and about three- fourths of Earth's surface land area. Sedimentary rocks cover almost all of the ocean floor and about three- fourths of Earth's surface land area.

Metamorphic Rock Heat, pressure, and hot fluids cause rocks to change into other rocks. Heat, pressure, and hot fluids cause rocks to change into other rocks. Where would this most likely occur? Where would this most likely occur?

Metamorphic Rock Heat, pressure, and hot fluids cause rocks to change into other rocks. Heat, pressure, and hot fluids cause rocks to change into other rocks. Where would this most likely occur? within the Earth Where would this most likely occur? within the Earth - at subduction zones - when magma cools

Metamorphic Rock The geologic processes that created the North Cascades changed the original rock into metamorphic rock. Formed from compression of Tectonic plates

Types of Metamorphic Rock Types of Metamorphic Rock Slate is a common form that is easily split into slabs Slate is a common form that is easily split into slabs Gneiss (pronounced “nice”) contains light and dark bands Gneiss (pronounced “nice”) contains light and dark bands Granite is also a common type Granite is also a common type

The Rock Cycle Almost all of the rock that we have on Earth today is made of the same stuff as the rocks that dinosaurs and other ancient life forms walked, crawled, or swam over. While the stuff that rocks are made from has stayed the same, the rocks themselves, have not. Over time rocks are recycled into other rocks. Almost all of the rock that we have on Earth today is made of the same stuff as the rocks that dinosaurs and other ancient life forms walked, crawled, or swam over. While the stuff that rocks are made from has stayed the same, the rocks themselves, have not. Over time rocks are recycled into other rocks.

The Rock Cycle