147 Cards in this Set
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Who developed and promoted the concept of uniformitarianism?
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James Hutton
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What is a scientific principle that has withstood many tests, is a simple explanation, and explains a wide range of phenomena
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Theory
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Which process is not explained by the nebular theory?
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Development of earth's atmosphere
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Which of the following earth layers is characterized by large amounts of peridotite and relatively weak physical structure?
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Asthenosphere
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What was the first rock to form after Earth was created
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Igneous
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Which of the following criteria is not required to be classified as a mineral?
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-Includes wither oxygen or silicom in its chemical composition
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Which type of bond occurs when electons are shared by tow atoms
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Covalent bond
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Which of the following mineral properties refers to the quality of light reflected from the surface of the mineral?
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Luster
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Which of the following minerals can you scratch with your fingernail?
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Talc
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Which of the following minerals or groups have single- chain structures of silicon- oxygen tetrahedra
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Pyroxene group
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Which category of igneous rock would you expect to find relatively small crystals of silicate minerals?
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Extrusive minerals
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Which of the following is used to describe a relatively common coarse- grained igneous rock with mineral crystals that are identified with the naked eye?
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Phaneritic
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Which of the following fine grained igneous rocks is similar in composition to granite?
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Rhyolite
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According to Bowen's reaction series, which silicate mineral group undergoes a continuous alteration (progressiely more sodium) as magma cools?
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Plagioclase feldspar
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What factor does NOT increase the viscosity of magma?
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Magma Chamber Size
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Which of the following lava types flows the fastest when on the ground
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Pahoehoe
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Which of the following types of volcanoes is mostly comprised of lapilli (pyroclastics)?
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Cinder cone
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Which of the following features is primarily responsible for the majority of flood basalts?
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Fissures
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Which of the following rocks could be described as having low porosity, fissility, and a fine-grained texture?
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Shale
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How do evaporites form?
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Precipitation of mineral crystals
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Which two processes are associated with diagenesis of sedimentary rocks?
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Compaction and cementation
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Which of the following environments would be considered "transitional" between the land and ocean
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Delta
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Geology
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Defn:Science that pursues an understanding of Earth
-Lots of field and lab work and application of computational models to natural systems
-Very complicated- lots of interacting parts (e.g. rocks, water, people)-Submicroscopic to global scales
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Geology relates to what 6 branches?
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1) Geography (geomorphology and paleogeography)
2) Biology (Paleontology)
3) Chemistry (Geochemistry)
4) Physics (Geophysics)
5) Astronomy (Cosmogony and geodesy)
6) Meteorology (Paleoclimatology and hydrology)
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What are the 2 broad categories of geology?
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1) Physical geology
2) Historical geology
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Physical geology
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examines earth materials and seeks to understand the many processes that operate on our planet, both the interir and on the exterior surface
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Historical geology
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Seeks an understanding of the origin of Earth and its development through time
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Geology people, and the environment
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-Many important relations exist between people and the natural environment
-Problems and issues addressed by geology- natural hazards, resources, world population growth, and environmental issues
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Catastrophism
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-Notably from James Ussher (mid 1600s) and Baron Georges Cuvier (around 1800)
-Earth created in 4004 B.C.; important changes to the physical environment are a result of catastrophic events
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The channeled Scablands
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J Harlan Bretz (1923); periodic outbursts water impounded by glacial ice dams;
-occured over eastern washington
-flood peaks estimated to be 1,ooo ft. deep with the velocity of a fire hose
-jokulhlaups
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Uniformitarianism
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-James Hutton (1788)
-Advocated by Charles Lyell (used by charles darwin)
-The simplest explanations for Earth's development rest on the idea that physical processes (erosion, deposition, gravity, etc.) that are observed in contemporary settings have acted over longer geological timesca…
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Time
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-Difference between geology and other sciences
-takes more than lifetimes, dome geological occurences happen once every 500 years
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Official unit of time
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-Second
-10 Ma= 10 million years ago
-10 m.y.= An interval of time lasting o10 million years
-10 ka BP=10,000 years before present (1950)
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Absolute dating
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Determination of a specific age or range of years for an event
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Relative Dating
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Determination of the chronological order of events without knowing their specific age
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How long has earth existed in years
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4.6 billion years
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Scientific Method
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1) observation
2) Hypotheses or multiworking hypotheses
3) experiment
4) results
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Hypothesis
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tentative explanation initially offered for a set of observations- must fit other scenarios other than that from which it was derived
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Theory
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when a hypotheses withstands many tests
-a simple explanation available and explains a wide range of phenomena
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Law
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A theory for which there appear to be no sensible challenges is referred to as a scientific law
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what is Observational
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-Rocks
-Sediment
-Structures or features
-Water
-Maps
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Experimental
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-Chemical
-Geophysical
Computer models
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What are Earth's four interactive spheres
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1)hydrosphere
2) atmosphere
3) Biosphere
4) Geosphere
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Hydrosphere
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Characterized by moving water in the form of oceans, rivers, lakes, glaciers, groundwater, precipitation, and water vapor
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Atmosphere
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A very thin, life-giving, gaseous atmosphere (1/2 below 3.5 miles; 90 % below 10 miles)-weather and climate
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Biosphere
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The terrestrial and oceanic life
-Concentrated in a narrow band near Earth's surface
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Geosphere
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very large and inorganic
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System
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-group of interacting, or interdependent, parts that form a complex whole
-humans are part of the Earth System
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Nebular Theory
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A. Gravitational Collapse
B. Contradiction and conversion of gravitational to thermal energy- solar nebula
C. Cooling and particle condensation
D. Collisions and coalscence of tiny particles
E. Planetesimal growth of rocky inner planets, and gaseous, icy, less dense outer planets
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Aggregation of the earth simultaneous with giant imact that dislodged matter, wich would eventually become the _____
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moon
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Crust
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relatively thin (7-70 km) rocky, outer skin; composed of both continental (granitic) crust and oceanic (basalt) crust
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Mantle
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82% of Earth's volume; a solid rocky shell mostly of peridotite (more Mg and Fe than crust)
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Core
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Outer (liquid) and inner (solid) center of earth
-Mostly an Fe-Ni alloy; highly dense
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Lithosphere
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Crust and part of upper mantle;
the outer, rigid shell of the Earth; physically detatched from the underlying asthenosphere
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Asthenosphere
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pressure/ temperature support some melting- weak part of the mantle immediately beneath the lithosphere
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Transition zone and lower mantle
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Increase in pressure results in increasing strength and density
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Inner and outer core
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Inner (solid) Outer (liquid)
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The lithosphere "____" on top of the asthenosphere
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rides
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3 Major rock types
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1) Igneous
2) Sedimentary
3) metamorphic
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Igneous
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Formed by the cooling and solidification of magma (molten rock)
-granite and basalt
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Sedimentary
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-Formed by the layered accumulation of sediment at the Earth's surface; sediment is derived from the weathering of existing rocks;
-sandstone and limestone
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Metamorphic Rocks
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Formed by changing preexisting igneous, sedimentary, or metamorphic rocks; requires heat and pressure;
-gneiss and marble
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rock cycle
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Long term interrelations between different rock types
-starts with crystallization of magma into igneous rock
-includes their formation and changes along the way
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Marble
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metamorphosed limestone
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gneiss
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metamorphic rock
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Continents
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low-density rocks allow them to "float" higher above mantle
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Ocean basins
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high-density rocks
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Mountain belts
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Young mountains in 2 primary zones (western N and S America; south Eurasia); deformed rocks
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Stable interior (cratons)
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-expansive, flat, igneous and metamorphic shields of very ancient, eroded mountains; stable platforms covered with sediments and sedimentary rock
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Continental margins
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Flooded continental slope (boundary between continents and ocean basins), and continental rise (sediments piled at the foot of the slope)
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Deep-ocean basins
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-Flat abyssal plains
-Scattered volcanic seamounts
-Very deep, linear deep-ocean trenches
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Oceanic ridges
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Continuous belt of uplifted, fractured igneous rock
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POWERPOINT 2
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POWERPOINT 2
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What is a mineral
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1) is naturally occurring
2) is generally inorganic (or is made through inorganic processes- like shells)
3)is a crystalline solid (Hg) is the only exception
4) has an orderly crystalline structure
5) has a unique chemical composition with minor variations
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Over ______known minerals and most rocks are formed by a handful off them
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4000
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What is a rock
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-naturally occurring
-consolidated mixture (aggregate) of minerals or non minerals
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Atom
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-the smallest particle that can NOT be chemically split
-consists of a nucleus surrounded by negatively charged electrons
-a nucleus consists of dense neutrons (no charge) and protons (+ charge)
-Electrons orbit the nucleus in principal shells (energy levels). Outer shell with valence …
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Atomic number
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# of protons in the nucleus of an atom- define chemical and physical properties
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Element
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a group with the same kind of atoms
-basic building blocks of minerals
-some minerals are made of 1 element- others are chemical compounds of different elemnets
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Valence (outer shell) electrons
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2 maximum in shell closest to nucleus- 8 maximum in shells further out
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Octet rule
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atoms tend to gain, lose, or share electrons with other atoms (chemical bond) to fill valence shell w/ 8 electrons
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Ionic bond
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electron transfer
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Covalent bond
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electron sharing
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Metallic bond
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electrons free to move among all atoms
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Ion
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an atom with a different number of electrons than protons
-Electrically charged cations (+) and anions (-charge)
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Ionic bond
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transfer of electons between oppositely charged ions
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Covalent bond
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atoms share elctons with another ti "fill up" their outermost valence shells- very strong bond
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Metallic bond
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Valence electrons move around from one atom to another
-conductive metals
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3 ways to form minerals
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1)precipitation from solution
2)crystallization of molten rock
3) biological deposition by water-dwelling organisms (e.g. corals, microorganisms
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Physical properties used to identify minerals include
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-luster (optical)
-transmission of light (optical)
-color (optical)
-Streak (optical)
-Crystal habit
-Tenacity (strength)
-hardness (strength)
-cleavage (strength)
-Fracture (strength)
-Specific gravity (density)
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Luster
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Appearance or quality of light reflected from a surface
-Metalic/ nonmetallic
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Transmission of light
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through a mineral
-opaque: no light
-Translucent: light visible
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Color
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can only use for a few htings because most minerals have lots of tints
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Streak
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Color of powdered mineral
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Crystal habit
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The characteristic shape of a crystal or aggregate of crystals
-equant (equidimensional)
-bladed
-fibrous
tabular
-prismatic
-platy
-blocky
-botryoidal
- a few minerals have more than one habit
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Tenacity
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resistance of a mineral to breaking or deforming
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Hardness
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resistance of a mineral to abrasion or scratching
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Cleavage
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tendency of a mineral to break along planes of weak bonding- some minerals do not exhibt cleavage (but have crystal habit)
-described by # of cleavage directions (angles at which they meet)
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Fracture
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mineral breaks to form irregular surfaces- occurs when a mineral aggregate is equally strong in all directions
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Density
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mass (weight per unit colume)
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Specific gravity
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ratio of a mineral's weight to the weight of an equal volume of water
-commonly ranges between 2-3
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Crystal
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any natural solid with an orderly, repeating internal structure- doesn't require smooth sided faces
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Unit cells
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Combinations of differently-sized ions and atoms- ____ form that maximize the distance between ions of similar charge
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Steno's law (lawof constancy of interfacial angles)
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Angles between equivalent crystal faces of the same mineral are constant
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Polymorphs
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Minerals with exactly the same chemical compostition bt a different internal structure
-transformations through a phase change
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classification for minerals includes what three things?
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-mineral species
-mineral classes
-mineral varieties
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Mineral species
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-Contains specimens that exhibit similar internal structures and chemical compostitions
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Mineral class
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a group of minerals based on theri anions
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Mineral variety
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simply a slight variation of one mineral
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2 broadcast groups
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1) silicates (Si and O) that form by crystallization of molten rock
2) nonsilicates everything else
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Silicon-oxygen tetrahedron (SiO4^4-)
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4 small oxygens covalently bonded to 1 small silicon ion- net negative charge of -4
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Polymerization
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of individual silicate tetrahedra by sharing oxygens- diverse silicate minerals
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Light silicates
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usually light in color, less dense, and contain Al, K, Ca, or Na
1)feldspar group
2) quartz
3) muscovite
4) clay minerals (secondary)
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Dark silicates
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generally dark in color, more dense, contain Fe or Mg
1)Olivene group
2)pyroxene group
3)amphibole group
4)Biotite
5)garnet
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Feldspars
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most common mineral group >50% of earth's crust
1)potassium feldspar
2) plagioclase feldspar
-in igneous rocks: commonly rectangular with smooth shiny faces
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Quartz
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(silica)-entirely composed of silicon and oxygen-3-D structure- only covalent bonds and hard, resistant, no cleavage, conchoidal fracture
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Muscovite
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Mica family-sheet structure with excellent cleavage in one direction
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Clay minerals
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weathering of rocks at the Earth's surface- microscopic sheet structures
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Olivene
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dark silicate
-individual tetrahedra
-form in high temperstures
-greenish or blackish
-glassy
-conchoidal fracture
-upper mantle
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Pyroxene
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-Single chains
-Augite in basalt- 90 degree cleavage
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Amphibole
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-double chains
-hornblende in granites
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biotite
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mica family with sheet structure- present in granites
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Nonsilicate minerals divided into groups based on
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common anions or complexes (negatively charged ions)
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Igneous rocks
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formed by the cooling and solidification of molten rock into silicate minerals; makes up the vast majority of Earth's volume
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Magma
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formed by partial melting in Earth's crust and upper mantle- less dense and rises toward the surface
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Lava
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magma that reaches the surface either diffusively or explosively
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Magma consists of three parts
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1)liquid
2)solid
3) gaseous
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Crystallization
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-magma cools-ions move more slowly-join to make silicate structures- tetrahedra join into other structures
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Extrusive (volcanic) igneous rocks
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form when magma crystallizes at Earth's surface
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Intrusive (plutonice) igneous rocks
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form when magma crystallizes at depth beneath Earth's surface
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Igneous composition
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1) felsic (granitic)
2) mafic (basaltic)
3)andesitic (intermediate)
4)ultramafic
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Felsic (granitic)
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-continental crust
-mostly comprised of feldspar and quartz
-from viscous magma
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Mafic (basaltic)
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rocks have subsantial amounts of dark silicates
-oceanic crust and some lava flows
-no quartz
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Andesitic
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composition between granite and basaltic rocks
-volcanic activity at margins of continents
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Ultramafic
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upper mantle
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Texture
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refers to the size, shape, and arrangements of crystals.
For igneous rocks it depends on
-rate at which magma cools
-amount of silica
-amount of dissolved gases in magma
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Amphanitic
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Fine grained, microscopic crystals; rapid cooling at surface or in shallow, intrusive masses
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Phaneritic
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coarse-grained; slow solidification beneath surface; intrusive igneous rocks; large, identifiable crystals
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Porphyritic
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Large crystals form slowly at depth; small crystal matrix forms during a sudden change of the environment
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Rock is referred to as...
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porphyry
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Vesicular
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rapid cooling allows volatiles to expnad and escape as lava cools; pumice: explosive , silica-rich lava; scoria: basalt with numerous vesicles
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Glassy
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Magma ejecting into the atmosphere, thereby cooling very quickly, or from viscous magma with a high silica content that impedes ion mobility; obsidian: a black, glassy igneous rock
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Pyroclastic
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Fragmental texture; formed of individually ejected rock fragments that consolidated; welded tuff is formed of fine glass fragments
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Pegmatitic
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Exceptionally coarse-grained (pegmatites); occur in veins around large igneous intrusions;unusualy high content of volatiles-fluid rich environment for crystallization
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Igneous rocks classified based on:
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1) mineral compostition
2) texture
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Granite
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Common phaneritic igneous rock
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Rhyolite
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extrusive; same composition as granite with some glass
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GLY 101:Final Exam