Earth s Structure Book----NOTES CHAPTER 2 LESSON 1: PROPERTIES OF MINERALS pg. 32 A. A MINERAL is Found in NATURE SOLID Made of CRYSTALS = object which has flat sides that meet @ sharp edges INORGANIC= made from materials that were NOT part of something once living. Almost 4000 minerals found on Earth Has a CHEMICAL FORMULA Ex: NaCl, C, etc. I. How Are Minerals Identified?? A. Color- usually not enough to identify a mineral B. Streak= color of a mineral in powdered form (Ex: graphite pencil leaves streak on your paper)
C. Luster = how light is reflected from minerals surface 1. Metallic- shiny like chrome on car 2. Nonmetallic (glassy, earthy, silky, waxy & pearly) D. Hardness 1. 1812 Friedrich Mohsinvented scale to help identify minerals by hardness 2. Mohs Hardness Scale- goes from 1 (softest) to 10 (hardest) minerals E. Density 1. To find density divide mass by volume Density = Mass (grams ) / Volume (cm 3 ) è To find volume of irregular object place it into water & see how much water is displaced & that is its volume (10 then to 15.. so 5 cm 3 is volume) 2. Pyrite has density of 5 g/cm 3 & Gold is 19 F. Crystal Structure 1. Different minerals have crystals that are shaped different a. Halite (salt) is cubic 2. Geologists classify by number of faces/sides on the crystal & measure angles at which the faces meet
G. Cleavage & Fracture 1. Cleavage = splits along a FLAT surface (Ex: mica) 2. Fracture = breaks apart in an irregular way (Ex: quartz) H. Lightà forms rays when passed thru mineral (Calcite- see a double image) i. Under black light some glow diff. color.. its one way to tell if a diamond is real I. Magnetism à Magnetite is magnetic J. HCl ( hydrochloric acid ) make Calcite fizz/bubble II. How Do Minerals Form? ORGANIC PROCESSES Ocean animals make shells made out of mineral calcite CRYSTALS FROM SOLUTIONS 1. Solution = mixture in which one substance is dissolved in another a. Water can evaporate in dry areas and leave behind salt crystals (halite) b. Minerals from hot water solutions (Ex: gold veins) 2. Geode= rounded, hollow rock that is often lined w/ mineral crystals MAGMA OR LAVA COOL & HARDEN 1. Magma & Lava are often rich in oxygen & silicon.. called SILICATES a. Silicates make up majority of minerals in Earth s crust à You can find mineral deposits all over the world (SEE MAP ON PAGE 43)
Ch 2 LESSON 2: CLASSIFYING ROCKS pg. 44 I. How Do Geologists Classify Rocks? è Rocks- made of mixture of minerals & other materials è About 20 minerals make up most of the rocks in Earth s crust BY MINERAL COMPOSITION & COLOR 1. Light Color if rock is HIGH in silica (silicon & oxygen) à Granite 2. Dark Color if rock is LOW in silica à Basalt BY TEXTURE (LOOK & FEEL OF SURFACE) 1. Based on Grain Size (fine, coarse, no visible grain) 2. Based on Grain Shape (rounded, jagged) 3. Based on Grain Pattern (non-banded, banded) BY ORIGIN.. which of the 3 below is it? a. Igneous Rock = forms from cooling of magma or lava b. Sedimentary Rock = forms when small particles of rocks or remains of plants & animals are pressed & cemented together c. Metamorphic Rock = forms when a rock is changed by heat or pressure, or by chemical reactions Ch 2 LESSON 6: THE ROCK CYCLE pg. 62 I. What Is The Rock Cycle??? è Rock Cycle = series of processes that occur on Earth s surface & in the crust & mantle that SLOWLY change rocks from one kind to another. A. Pathways Through the Rock Cycle 1. There can be MANY pathways
2. Rock cycle can happen through: i. Weathering = process that BREAKS DOWN rocks ii. Erosion = process of WEARING down and CARRYING AWAY iii. Melting iv. Heat v. Pressure B. Rock Cycle & Plate Tectonics 1. Rock cycle is closely related to plate tectonics C. Conservation of Material in the Rock Cycle à Even though rocks change form and look. MATTER IS NOT CREATED OR DESTROYED!! D. What Causes Weathering? EARTH S SURFACE BOOK PGS. 39-45 1. Mechanical weathering = rocks break by physical process, chemical makeup STAYS THE SAME!! Mechanical Weathering CAUSED BY: a. growing plants. Ex: tree roots b. burrowing animals. Ex: prairie dogs, insects c. freezing & thawing..ex: our sidewalks d. abrasion sand & other rock particles wear away exposed rock 2. Chemical weathering = chemical rxns dissolve or change the minerals in rocks, chemical make up CHANGES!! Chemical Weathering CAUSED BY: a. Carbon Dioxide. When CO 2 dissolves in H 2 O it becomes a weak acid (Ex: dissolves marble & limestone) b. Oxygen.oxidation (rust- from O 2 ) c. Living Organisms plant roots grown & make weak acids (Ex: lichen)
d. Acid Rain. When pollution mixes with rain.. (Ex: pits in famous statues) ** Climate affects chemical weathering..(faster in warm, wet climates) * Weathering helps to form soil. Ch 2 LESSON 3: IGNEOUS ROCKS pg. 48 I. How Do Geologists classify Igneous Rocks?? è Igneous Rocks form from high heat. By ORIGIN By TEXTURE By MINERAL COMPOSITION 1. Extrusive Rock = igneous rock that formed on surface of Earth a. Basalt is most common extrusive rock 2. Intrusive Rock = igneous rock that formed inside Earth a. Granite is most common intrusive rock 1. Texture depends on size & shape of crystals, except for volcanic glass (don t have crystal structure) 2. Cools RAPIDLY à fine grained, w/ small or no crystals (Ex: rhyolite) 3. Cools SLOWLY à coarse grained, w/ large crystals (Ex: granite) Intrusive rocks have LARGER grains than extrusive, because they can cool slowly. 1. Low in silica dark colored rocks (Ex: basalt) 2. High in silica light colored rocks (Ex: granite)
II. How Are Igneous Rocks Used?? è Igneous rocks are hard, dense & durable Granite- used in building materials & statues (Egyptians), bridges & public buildings, counter tops(usa) Basalt -- used for cobblestones on streets, landscaping Pumice- cleaning & polishing, lava soap, foot scrub Obsidian- make knives Perlite mixed w/ soil to start vegi seeds Ch 2 LESSON 4: SEDIMENTARY ROCKS pg. 52 I. How Do Sedimentary Rocks Form?? WE SEE SEDIMENTARY ROCKS IN THE BADLANDS!! è Sediment = small, solid pieces of material that come from rocks or living things A. Sedimentary Rocks are Formed by: WEATHERING EROSION DEPOSITION COMPACTION CEMENTATION Processes that break down rocks When running water, wind, or ice carry away bits of broken up rock. When sediment settles out of wind or water that is carrying it. When sediments are packed together. (Think: Trash Compactor) Dissolved minerals crystallize & glue particles together.
II. Three Major Types of Sedimentary Rocks CLASTIC ROCKS = formed when rock fragments are squeezed together a. Fragments can range from super tiny to boulders b. Examples of Clastic Rocks Sandstone- forms from sand on beaches, ocean floor, riverbeds & sand dunes Shale- forms from tiny particles of clay Conglomerate- has rounded edges Breccia- has sharp edges ORGANIC ROCKS = formed when plants/animal remains are deposited in layers a. Examples of Organic Rocks Coal- swamp plants buried in water.. layers are squeezed together Limestone- forms in ocean from coral, clams, oysters etc. layers get cemented & compacted CHEMICAL ROCKS = formed when minerals dissolved in a water solution crystallize or from deposits left behind when seas & lakes evaporate a. Examples of Chemical Rocks Rock Salt A. Uses of Sedimentary Rocks 1. Chert in Spearheads & Flint in arrowheads 2. White House is made of sandstone 3. Limestone is used to make cement & steel Ch 2 LESSON 5: METAMORPHIC ROCKS pg. 58 A. Metamorphic Rock- forms from heat AND pressure B. How Do We Classify Metamorphic Rock? 1. By Arrangement of Grains Making up The Rocks a. Foliated Rocks= thin, flat layering, mineral grains line up (banded) i. Examples of Foliated Rocks Gneiss, Slate b. Non-foliated Rocks mineral grains arranged randomly i. Examples of Non-foliated Rocks- Marble, Quartzite
C. Metamorphic Rock Uses 1. Marble is used in sculpture (Lincoln Memorial), floors, buildings (Tower of Pisa) 2. Slate used in roofing, walkways, trim Organic EARTH S SURFACE BOOK PGS. 80-85 GLACIERS A. Glaciers= lg. mass of ice & snow moving on land by itself ** last major ice age ended 10,000 yrs ago. 1. glaciers can transport huge amts. of sediment and rock leave grooves on the rocks they pass by & totally change the landscape.
- 2. Glaciers are either a. Continental (ice sheets..like during Ice Ages ) OR b. Valley (found in mtn. valleys it is long & narrow) 3. Conditions needed to FORM a glacier: a. high snowfall in winter b. cool temps in summer 4. Conditions for glacier RETREAT ( when they get smaller) a. transition of ice to vapor b. snow evaporation c. strong winds d. ice melt à Global Warming?? Is it causing glacial retreat?? 5. Benefits of Glacier Retreat a.) opened up NW Passage (shipping route) in 2006 last open was in 1592 b.) opens up new land to build on 6. Negatives of Glacier Retreat a.) flooding b.) animal/plant species extinction 7. Types of glacial deposits. a.) Till- mix of diff. sized sediments that drop from a glacier when it retreats b.) Outwash gravel & sand deposited by glacial melt water c.) Moraine- where a glacier deposits a mound or ridge (Ex: around Watertown) d.) Eskers winding ridge of sand & gravel (Ex: around Yankton)
8. Glaciers are IMPORTANT because. a.) erode mtn. tops b.) transform valleys (Ex: created Grand Canyon) c.) sand & gravel deposits that we use for roads, etc. à glacier outwash d.) Eastern SD rich soil à from glacier till e.) recreation (lakes/rivers) à created by moving glaciers