Rocks & minerals
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Rocks & minerals

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Rocks & minerals Rocks & minerals Presentation Transcript

  • Unit 2 Lithosphere• Rocks and Minerals
  • OK – so here’s the real introduction to Rocks & Minerals
  • What is a Mineral?• Solid Earth Materials• Naturally Occurring• Inorganic• Definite Chemical Formula• Definite Crystal Structure
  • Minerals
  • ESRT Pg 16Minerals can beidentified bytheir chemicaland physicalproperties.
  • Minerals Fist List ! Fi ve!High What is a Mineral?
  • What does that mean?!?!?! --Not a gas or a liquid So lid --Has a definite ,E shape and volume ar th Ma ter QUESTION? ial Is oil a mineral?? Answer… No, because it is a liquid.
  • NaturalWhat does that mean?!?!?! ly O --Not man-made ccurring
  • icWhat does that mean?!?!?! Inorgan --Not formed from living things or the remains of living things --NON-LIVING!! EXAMPLES 1. Coal is NOT a mineral because it comes from plants. 2. Amber is NOT a mineral because it comes from tree sap. 3. A pearl is NOT a mineral because it comes from oysters.
  • What does that mean?!?!?! ula --The elements that make orm up the minerals are combined lF in definite proportions ica em --Chemical formula can Ch be found on page 16 of ESRT. ite EXAMPLES -Gold (Au) fin De -Pyrite (FeS²) -Graphite (C) -Diamond (C)
  • What does that mean?!?!?! re --Atoms are arranged tu in a repeating pattern truc a lS --Each mineral has a y st different INTERNAL Cr ARRANGEMENT OF it e fin De ATOMS that gives it distinct physical and chemical properties
  • What does that mean?!?!?! re tuQUESTION truc lSHow does the mineral graphite,which is soft have the same s tachemical formula as diamond, Cry itewhich is the hardest mineral finin the world? DeANSWERBecause their internalarrangement of atoms are different
  • How are Minerals Identified??Fill in the spiderslegs as we go!!
  • ESRT Pg 16Minerals can beidentified bytheir chemicaland physicalproperties.
  • How are Minerals Identified?? Co --Least useful for lo r identification --One mineral can come in many colors EXAMPLE: --Hematite: Comes in black, red and brown
  • How are Minerals Identified?? 1. Some minerals are always the same color Sulfur 2. Some minerals can have many colors Rose Quartz Quartz Smoky Quartz
  • Colors can vary as a result of…A. Chemical Impurities– Cobalt compounds tend to be pink, purple, or blue Manganese—tends to produce pink colors
  • Colors can vary as a result of…B. Oxidation—exposure to air and water changing the color of the mineral. Ex. Rust --Iron is the dominant coloring agent in rocks and soils
  • How are Minerals Identified?? --the color of a mineral when it is finely powdered St rea --determined by k rubbing the mineral on a piece of tile Hematite has a reddish-brown streak.
  • How are Minerals Identified?? --describes how a mineral appears to reflect light There are 2 Lus t er categories in which a minerals luster can fall… Metallic OR Non-Metallic
  • How are Minerals Identified??A. Metallic– reflects light like metal (shiny) Graphite Galena Pyrite
  • How are Minerals Identified??B. Non-Metallic—any mineral which DOES NOT exhibit shiny metallic characteristicsEx. Quartz
  • Metallic or Non-Metallic?? Non-Metallic Mica Pearly luster Metallic Magnetite
  • Metallic or Non-Metallic?? Non-Metallic Pyroxene Dull luster
  • How are Minerals Identified?? --Resistance of a mineral to being scratched --Moh’s Hardness Scale —compares the hardness of the mineral Hardness to 10 reference minerals.
  • How is Hardness Determined?? The scale consists of Softest number 1 through 10; 1 being the softest and 10 being the hardest. Each number represents a different mineral- each harder than the previous. The 10 Hardest minerals are to the left.
  • How is Hardness Determined?? Several common household items have a fixed hardness, and can be used to test for hardness.-Fingernail = 2.5-Copper penny = 3-3.5-Nail = 4.5-Knife blade = 5.5-Glass = 5.5-Steel file = 6.5-Streak plate = 7
  • What Determines Hardness?--Hardness is determined by a minerals internal arrangement of atoms.Ex. Diamond vs. Graphite -Diamond has hardness of 10 and graphite is ranked between 1 and 2. Diamond is about 40 times harder than graphite due to the way the atoms are arranged.--Hardness is the best property to use to identify a mineral.
  • How are Minerals Identified?? Cleavage—when a mineral breaks along a flat, smooth vag e or surface Clea re F ractu
  • Examples of Minerals that show Cleavage Mica exhibits basal cleavage. Galena exhibits cubic cleavage.
  • What Determines Cleavage? A minerals internal arrangement of atoms!!
  • How are Minerals Identified?? Fracture—When a mineral breaks along irregular rough surfaces. e or vag Clea ure EX. Quartz Fr act
  • How are Minerals Identified?? --The amount of matter in a given space (mass/volume) Depends on… r Heft Density o -kind of atoms which make up the mineral -how the atoms are arranged in the crystal lattice
  • How are Minerals Identified?? --Minerals have a characteristic crystal shape resulting from the atomic packing of the atoms when the Crystal Shape mineral is forming
  • How are Minerals Identified?? -Magnetism (Magnetite) -Glowing under ultraviolet light (Fluorite) -Salty taste (Halite) -Smell (Sulfur) Spe cial -Reaction to HCl Pr ope (Calcite) rtie s
  • IMPORTANT!• Remember on the Regent’s Exam most of the information about the mineral in a question will be given to you or you will observe from the diagrams on the Exam. Use them to your advantage. Make sure you know the basics about mineral identification and observe carefully…….• USE PAGE 16 OF THE ESRT
  • How are rocks formed?Rocks are classified by their process of formation.
  • Lithosphere
  • ROCKS Sedimentary Metamorphic Igneous sediments and minerals are compacted and cemented With dissolved mineralsClastic – pieces Organic/Bioclastic of other rocks Chemical – Remains of plants Cemented into Evaporites Or animals which rock From seawater Are transformed Into rock
  • pg 6 in your notes Sedimentary Rocks Form when And SEDIMENTS Minerals Are cemented together The 3 types of sedimentary rock are Clastic Chemical Organic
  • Texture and Grain Size• Texture is described based on grain size, grain shape, and grain pattern.• Most rocks are made up of tiny particles of minerals or other rocks, which are called grains.• A rock’s grains give it its texture
  • Origins of Sedimentary Rock – Draw an arrow from “CLASTIC”•Through the process of As the layers stack up, weathering they become heavier until the weight squeezes the, rock is loosened and layers together duringcarried away with wind andwater by compaction . erosion Dissolved minerals act as. The sediment then settles glue in a process knownout of the wind and water as .during deposition. The deposition Cementationsediment begins to settle outand form layers .
  • Earth Science Reference Table Page 7
  • • This is a sample of breccia, a coarse-grained sedimentary rock with coarse, angular fragments.
  • • This is a sample of sandstone, a sedimentary rock that formed from sand grains.
  • Chemical• Formed when minerals dissolved in water, precipitate out and form crystals on the sea floor – Includes evaporites.
  • Earth Science Reference Table Page 7
  • Organic (bioclastic) – rocks formed from the remains of plants and/or animals that undergoes a transformation into rock.
  • • This is a sample of limestone, a sedimentary rock made of calcium carbonate that formed under water indirectly from the remains of tiny marine organisms.
  • Coal Formation
  • Grand Canyon
  • Rocks classified on the basis of their formation (how they are made) Monomineralic Polymineralic Ex: GraniteComposed EX: Composedof 1 Limestone of many Feldspar,mineral - Calcite minerals quartz, hornblende
  • Igneous Rock • Igneous rock forms when magma or lava SolidifiesCOOLS Crystallizes hardens
  • Crystallization
  • TEXTURE Intrusive Extrusiveor Plutonic or VolcanicCoarse Grained Fine Grained (small crystals) large crystals Glassy Non-Vesicular Gas Pockets (vesicular)(no gas bubbles) Magma LAVA Underground Above ground Slow cooling FAST cooling
  • Granite vs. Obsidian ExtrusiveIntrusive
  • Igneous Rock Mineral CompositionLight Colored Dark ColoredRocks Called Rocks Called FELSIC MAFIC Low density High Density Rich in Aluminum Rich in IRON & Magnesium
  • Igneous Rock chart found on page 6 of Reference TablesHigh light it in your ESRT!
  • Rock characteristics can be determined using this chart
  • Mineral content can also be determined using this chart How to read it! How to read it!
  • Metamorphic RocksConditions that cause rocks toundergo metamorphism include :• Deep burial and pressure or hot contact zones• Metamorphic rocks are often found in mountainous regions You’ll have to add this to your notes on page 8
  • Metamorphic Rocks – formed when a rockis changed by Heat Pressure Chemical due Metamorphic rocks are to Contact characterized by: • Increased DENSITY • NEW Minerals • BANDING
  • Metamorphic Rocksare classified by thearrangement of their: MINERALS
  • Into two types of metamorphic rocks called: Foliated and Non - FoliatedWhere the minerals grains are Where the minerals grains are Squeezed and Not aligned curved or and appear folded MASSIVE Bottom of Page 7 of ESRT
  • Foliated (think FOLD) Mica SchistIncreased HEATand PRESSURE Gneiss
  • Non-Foliated• Massive Metamorphic rocks
  • Metamorphic Rock Chart (page 7 Earth Science Reference Table
  • • Increasing metamorphic change occurs with increasing temperatures and pressures.• If the melting point is reached, the change is no longer metamorphic, and igneous rocks are formed.
  • The Rock Cycle (Page 6 of Earth Science Reference Table)• The Rock Cycle describes the continually changing structure of rocks.
  • Distribution of Rocks in the U.S.