Chapter 2 Lecture - Earth Science PDF

Chapter 2 Lecture Earth Science Fourteenth Edition, Global Edition Matter and Minerals Jennifer Mangan James Madison University © 2015 Pearson Education Ltd.  Minerals: Building Blocks of Rocks Definition of a mineral...

Chapter 2 Lecture Earth Science Fourteenth Edition, Global Edition Matter and Minerals Jennifer Mangan James Madison University © 2015 Pearson Education Ltd.  Minerals: Building Blocks of Rocks Definition of a mineral – Natural – Inorganic – Solid – Possess an orderly internal structure of atoms – Have a definite chemical composition Rock – any naturally occurring solid mass of mineral or mineral-like matter © 2015 Pearson Education Ltd.  Rocks are Aggregates of Minerals © 2015 Pearson Education Ltd.  Atoms: Building Blocks of Minerals Atoms – Smallest particles of matter © 2015 Pearson Education Ltd.  Atomic Structure Nucleus – central part of an atom that contains – Protons – positive electrical charges – Neutrons – neutral electrical charges Electron shells – Surround nucleus – Contain electrons – negative electrical charges © 2015 Pearson Education Ltd.  Atomic Structure © 2015 Pearson Education Ltd.  Atoms Atomic number – Number of protons in an atom’s nucleus. Ions – Positively or negatively charged atoms due to electron gain or loss © 2015 Pearson Education Ltd.  Composition and Structure of Minerals Elements – Basic building blocks of minerals – Over 100 are known – Defined by their number of protons – Groups of the same type of atoms © 2015 Pearson Education Ltd.  Periodic table of the elements © 2015 Pearson Education Ltd.  Atomic Bonding Valence shell – An atom’s outermost shell Octet rule – Atoms gain, lose, or share electrons until their valence shells have 8 electrons Chemical bond – Transfer or sharing of electrons to achieve full valence shell © 2015 Pearson Education Ltd.  Atomic Bonding Ionic bond – Atoms bond together when oppositely charged ions attract © 2015 Pearson Education Ltd.  Atomic Bonding Covalent bond – Sharing of a pair of electrons between atoms © 2015 Pearson Education Ltd.  Atomic Bonding Metallic bond – Packed metal atoms have valence electrons free to move throughout the structure. © 2015 Pearson Education Ltd.  Minerals Physical properties of minerals – Habit – common crystal shape – Luster – appearance in reflected light – Color – Streak – color of mineral in powdered form – Hardness – ability to resist scratching or abrasion – Cleavage – tendency to break along planes of weak bonding © 2015 Pearson Education Ltd.  Metallic Luster: Galena © 2015 Pearson Education Ltd.  Color Color can be unreliable due to variations. © 2015 Pearson Education Ltd.  Streak © 2015 Pearson Education Ltd.  Crystal Shape, or Habit: Pyrite © 2015 Pearson Education Ltd.  Hardness: Mohs Scale © 2015 Pearson Education Ltd.  Cleavage: Micas © 2015 Pearson Education Ltd.  Minerals Physical properties of minerals – Fracture – random pattern of breakage – Specific gravity – mineral density – Tenacity – resistance to cutting, breaking, bending, and deformation © 2015 Pearson Education Ltd.  Conchoidal fracture © 2015 Pearson Education Ltd.  Minerals Other properties – Taste – Smell – Elasticity – Malleability – Double refraction – Magnetism – Feel – Reaction with hydrochloric acid © 2015 Pearson Education Ltd.  Mineral Groups Rock-forming minerals – Only a few dozen – Most abundant atoms in Earth’s crust are oxygen (46.6% by weight) and silicon (27.7% by weight) © 2015 Pearson Education Ltd.  Mineral Groups Eight elements compose most rock-forming minerals: – oxygen (O), – silicon (Si), – aluminum (Al) – iron (Fe) – calcium (Ca) – sodium (Na) – potassium (K) – magnesium (Mg) © 2015 Pearson Education Ltd.  Composition of Continental Crust © 2015 Pearson Education Ltd.  Mineral Groups Rock-forming silicates – Most common mineral group – Contain the silicon-oxygen tetrahedron Four oxygen atoms surrounding a much smaller silicon atom Combines with other atoms to form the various silicate structures © 2015 Pearson Education Ltd.  Mineral Groups Rock-forming silicates – Groups based upon tetrahedral arrangement Olivine – independent tetrahedra Pyroxene group – tetrahedra are arranged in chains Amphibole group – tetrahedra are arranged in double chains © 2015 Pearson Education Ltd.  Hornblende: An Amphibole © 2015 Pearson Education Ltd.  Mineral Groups Rock-forming silicates – Groups based upon tetrahedral arrangement Micas – tetrahedra are arranged in sheets – Two types of mica are biotite (dark) and muscovite (light) Feldspars – Three-dimensional network of tetrahedra © 2015 Pearson Education Ltd.  Mineral Groups Rock-forming silicates – Groups based upon tetrahedral arrangement Feldspars – most abundant group of minerals in Earth’s crust Quartz – three-dimensional network of tetrahedra © 2015 Pearson Education Ltd.  Potassium feldspar © 2015 Pearson Education Ltd.  Rose Quartz © 2015 Pearson Education Ltd.  Mineral Groups Nonsilicate minerals – major groups – Oxides – Sulfides – Carbonates – Halides – Native elements © 2015 Pearson Education Ltd.  Common Nonsilicate Mineral Groups © 2015 Pearson Education Ltd.  Minerals Mineral groups – Nonsilicate minerals Carbonates – A major rock-forming group – Found in the rocks limestone and marble Halite and gypsum are found in sedimentary rocks Many have economic value © 2015 Pearson Education Ltd.  Natural Resources Renewable – Can be replenished in relatively short time spans Corn, wind, water, etc. Nonrenewable – Earth has fixed quantities Oil, aluminum, natural gas, coal © 2015 Pearson Education Ltd.  Natural Resources Mineral resources – Mineral resources are occurrences of useful minerals that will eventually be extracted – Ore deposits are concentrations of metallic minerals that can be mined at a profit – Economic factors may change and influence a resource © 2015 Pearson Education Ltd.  Copper Mining © 2015 Pearson Education Ltd.