EARTH MATERIALS Chapter 26

MINERALS – 26.1 A. Common Elements 1. Elements in Earth’s Crust a. What are the elements found in the Earth’s Crust? Oxygen, Silicon, Aluminum, Iron, Calcium, Sodium, Potassium, and Magnesium.

b. What are the elements found in the Continental Crust b. What are the elements found in the Continental Crust? Greater abundance of less dense elements such as, Silicon, Oxygen, Aluminum, and Potassium.

c. What are the elements found in the Oceanic Crust c. What are the elements found in the Oceanic Crust? More dense materials such as, Iron, and Magnesium.

What’s a mineral? 1. Please Define Mineral: Naturally occurring, inorganic solid with a crystalline form.

Physical Properties of Minerals 1. Color is due to different elements found in the mineral.

Ruby is red because it contains more of the chemical impurity chromium than a sapphire, which is blue.

Mineral Identification 1. Color can be the least reliable property for mineral identification. The same mineral can occur naturally in a variety of colors. For example, quartz can be colorless, purple, yellow, gray, or rose-colored.

Luster a. Please Define Luster: Property of metals and alloys that describes having a shiny appearance.

Streak a. Please Define Streak: Color of a mineral in its powdered form.

3. Streak chart

a. Please Define Atomic arrangement: The orderly arrangement of atoms in a mineral’s structure. This arrangement of atoms can reflect the way a mineral breaks, how hard it is, and what type of crystal shape it has.

Cleavage a. Please Define Cleavage: Manner in which a mineral breaks along planes of weakness, creating sets of smooth parallel sides; determined by the arrangement of atoms in the mineral’s structure.

Fracture a. Please Define Fracture: Manner in which a mineral without cleavage will break, producing uneven, irregular surfaces.

Cleavage versus Fracture

Hardness a. Please Define Hardness: Measure of a mineral’s resistance to scratching, described by Mohs scale hardness.

Crystal shape a. Please Define Crystal shape: Crystal shapes are used to determine the crystal system that a mineral belongs to.

Mineral Formation 1. Minerals from hot water a. How does this happen? As hot water solution cools, its particles slow down and dissolved materials are able to crystallize out of solution.

Minerals from molten rock a. Please Define Magma: Molten rock material inside Earth.

Minerals from evaporation a. How does this happen? When water evaporates, dissolved mineral material can crystallize from a saturated solution.

Mineral Groups 1. Silicates a. Please Define Silicates: The basic building block for the silicate minerals is a simple silicate ion (SiO44-), composed of four oxygen atoms tightly bonded to a silicon atom. This forms a geometric structure called a tetrahedron.

Silicate structures a. Minerals of the crust 1.) What are some of the silicates from the Crust? a. Quartz, potassium Feldspar, from Continental Crust. b. Plagioclase feldspar from Oceanic Crust.

Nonsilicates a. Please Define Nonsilicates: Minerals that do not contain silicon. Examples are; carbonates, halides, oxides, sulfides, sulfates, and native elements such as iron, copper, and sulfur.

Mineral Uses 1. What are some uses of Minerals? The mineral halite (NaCl) is used to flavor and preserve food. Gold and Silver is used for currency. Hematite or Iron Ore is used to make iron and steel. Quartz or SiO2 is used to make glass and calcite or cement.

IGNEOUS ROCKS – 26.2 A. What’s a rock? 1. Please Define Rock: Naturally formed mixture of minerals, rock fragments or volcanic glass, bound together, identified based on composition and texture.

Intrusive Igneous Rocks 1. Please Define Intrusive Igneous Rocks: Rock that formed from magma that solidified within Earth’s crust, also called Plutonic rock.

Magma composition a. Bowen’s Reaction Series 1.) What is Bowen’s Reaction Series? Simultaneous crystallization of silicate minerals with a decrease in temperature.

1.) What are the three Magma Types? (a) Mafic rocks- poor in silica and dense and comprise the Oceanic Crust. (b) Felsic rocks- rich in silica and have low densities that comprise the Continental Crust. (c) Intermediate Rocks- have both mafic and felsic.

Intrusive rock textures a. What is Intrusive rock textures? Rocks that cooled slowly underground and have coarse-grained textures. Examples of such rocks are granite, diorite, and gabbro.

Extrusive Igneous Rocks 1. Please Define Extrusive Igneous Rocks: Rock that formed from lava or ash that solidified on Earth’s surface. Obsidian is an example of rock that cooled so quickly that almost no crystals are formed. Obsidian appears glassy.

Other textures a. What are other Textures? Pumice and scoria are examples of extrusive igneous rocks that have vesicular texture. These rocks formed as trapped gases escape from a volcano during an eruption. Another type of texture, called porphyritic texture, results when minerals cool at different rates and create a rock with two different-size crystals.

Scoria- vesicular texture Granite- porphyritic texture

Common Igneous Rocks 1. Name three Common Intrusive Igneous Rocks: a. Granite b. Diorite c. Gabbro

Name three Common Extrusive Igneous Rocks: a. Rhyolite b. Andesite c. Basalt

Gases a. What are some gases found in Magma? 1.) Water vapor 2.) Carbon dioxide

SEDIMENTARY ROCKS – 26.3 A. Clasts 1. Please Define Clasts: Small rock and mineral fragments that can become part of another rock.

Weathering a. Please Define Weathering: Process that involves the physical of chemical breakdown of materials on Earth’s surface.

Transportation and deposition a. Please Define Pore Space: Empty space between clasts, can contain water, oil and natural gas.

Compaction and cementation a. Please Define Compaction: Process by which clasts stick together due to the weight of overlying material.

b. Please Define Cementation: Process of minerals precipitating out of solution into the spaces between clasts.

Detrital Sedimentary Rocks 1. Please Define Detrital: Sedimentary rocks that are made mostly of clasts. Geologists classify detrital sedimentary rocks based on clast size. In order of decreasing size, clasts are classified as gravel, sand, silt, and mud or clay.

Clast size a. What can Clast size be used for? The size of a clast can be used to infer how the clast was transported. It takes more force to move large clasts than it takes to move small clasts.

Composition a. What is Composition? Detrital sedimentary rock composition depends on the type of rock material that is weathered, transported, and deposited.

a. How are sedimentary Rocks Classified? Classification a. How are sedimentary Rocks Classified? Geologist classify detrital sedimentary rocks based on clast size.

C. Chemical Sedimentary Rocks 1. How do Chemical Sedimentary Rocks form? Chemical sedimentary rocks form from water that contains dissolved solids. Rock salt and gypsum are two examples of chemical sedimentary rocks.

Biochemical Sedimentary Rocks 1. What are Biochemical Sedimentary Rocks? If sedimentary rocks contain the remains of living organisms, they are biochemical sedimentary rocks. Limestone and coal are examples of Biochemical Sedimentary Rocks.

Coal a. What is Coal? Coal is composed almost entirely of the carbon that remains after plant material is compressed underground.

Formation of coal 1.) Where does Coal Form? Coal usually develops from peat, a brown, lightweight deposit of moss and other plant matter.

b. Formation of coal

METAMORPHIC ROCKS AND THE ROCK CYCLE- 26.4 A. Metamorphic Rocks 1. Please Define Metamorphic Rock: Igneous or sedimentary rocks that have been changed by any combination of heat, pressure, and chemical reactions.

Regional and contact metamorphism a. Please Define Regional Metamorphism: Metamorphic changes in rocks that occur over large areas.

Please Define Contact Metamorphism: Localized metamorphic changes that occurs in a small area, as when magma intrudes into or is in contact with the rock.

Composition a. Please Define Composition: The presence of water within rock enables chemical reactions to occur. Water can flow into cracks or pores in rock and cause atoms in minerals to rearrange and change composition.

Mineral composition 1.) Please Define Mineral composition: Clay minerals, mica, and amphiboles are examples of minerals that contain water in their crystal structures.

Textures a. Please Define Texture: Textures describes the size, shape, and arrangement of the crystals or grains in a rock.

b. Please Define Foliated: Texture of some metamorphic rocks in which crystals are arranged in layers and bands as a result of high pressure conditions.

1.) Name some Foliated Rocks: (a.) Slate c. Foliated rocks 1.) Name some Foliated Rocks: (a.) Slate (b.) Phyllite (c.) Schist (d.) Gneiss

Nonfoliated rocks Definition: Nonfoliated metamorphic rocks tend to have random crystal orientation and are uniform in color. 1.) Name some Nonfoliated rocks (a.) Quartzite came from quartz (b.) Marble came from limestone

Classification a. How are Metamorphic rocks Classified? Metamorphic rocks can be classified based on texture and mineral composition.

The Rock Cycle 1. Please Define the Rock Cycle: The continual changing of rocks into different types through processes such as high temperature and pressure, weathering, erosion and sedimentation.

Conservation of matter a. What is the Conservation of Matter as it applies to the Rock Cycle? Minerals in rocks are neither created nor destroyed but are changed over time by heat and pressure to another type of rock.

CHAPTER 26 REVIEW p. 840. A. Check Concepts 1. Please do Check Concepts 41-47, p. 840. B. Standardized Test Practice 1. Please do Standardized Test Practice 1-9, p. 842.