Geology1

40. Minerals: definition, various classes, properties, methods of identification
 * Definition: naturally occurring, inorganic, crystalline solid (ordered internal arrangement of atoms), with narrowly defined chemical composition and characteristic physical properties. **
 * Only about 2 dozen are very common because most of crust is made up of only 9 elements **
 * O-46.6%, Si-27.7%, Al, Fe, Ca, Na, K, Mg in order of abundance **
 * 9 Classes: **
 * 1. Silicates Si, O (SiO4 tetrahedron) **
 * May be single, chains, sheets or 3-D networks of tetrahedral **
 * Feromagnesian silicates – contain Fe, Mg, or both; dark and dense **
 * e.g., olivine, biotite, pyroxene, amphibole **
 * Nonferromagensian silicates – lack Fe, Mg; light in color, less dense **
 * e.g., feldspars, quartz, muscovite **
 * 2. Carbonates (CO3)-2 **

**Calcium carbonate – aragonite, calcite, dolomite **
41. Rock cycle: Interrelationships among rock types 42. Rocks: classification of each type (texture, composition), identification
 * Component of limestone and dolostone **
 * 3. Oxides – contain O-2; hematite, magnetite **
 * 4, Halides – contain halogen like F- or Cl-; halite, fluorite **
 * 5. Hydroxides – contain (OH)-1; limonite **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">6. Phosphates – contain (PO4)-3; apatite **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">7. Sulfides – contain S-2; galena, pyrite **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">8. Sulfates – contain (SO4)-2; anhydrite, gypsum **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">9. Native elements – gold, silver, diamond **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Properties used for identification **
 * 1) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Luster – quality and intensity of light reflected from surface; metallic or nonmetallic (glassy, pearly, earthy, brilliant, etc.) **
 * 2) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Color – very variable, least useful for most minerals **
 * 3) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Crystal form – external expression of internal orderly arrangement of atoms; cubic, hexagonal **
 * 4) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Streak – color in powdered form, very reliable **
 * 5) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Hardness – measure of resistance to abrasion/scratching; Mohs scale allows comparison to 10 minerals and ranks from 1 (softest-talc) to 10 (hardness-diamond) **
 * 6) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Cleavage and fracture – Cleavage: breaking along smooth planes or weak bonding (good, poor, direction, angle); fracture: breaking along uneven or conchoidal surface **
 * 7) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Specific gravity/density- ratio of its weight to weight of equal volume of water **
 * 8) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Double refraction – object viewed through transparent sample has double image (calcite) **
 * 9) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Hydrochloric acid – carbonates react and release carbon dioxide **
 * 10) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Magnetism – for minerals with high iron content like magnetite **
 * 11) **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Taste – salty taste of halite **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">12. Feel – graphite is greasy, talc is soapy **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">(Monroe, Wicander, Hazlett, p. 77-90) **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">DS **
 * Good 0 KMS**
 * Good MarkW**
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Rock cycle is way of viewing interrelationships between Earth’s internal and external processes (weathering, transportation, deposition with magma generation and metamorphism). Many alternative paths. Plate tectonics is the mechanism that drives the cycle and recycles groups between Earth’s interior and its surface. **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">DS **
 * (See #43-46)**

43. Igneous: common types, formation, textures, basic compositions (felsic, mafic, intermediate), extrusive versus intrusive
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Intrusive/plutonic rocks – magma (melt) that cools and crystallizes slowly below the surface. **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Granite, diorite, gabbro, peridotite (most Fe,Mg; least silica) **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Extrusive/volcanic rocks – form quickly (minutes to hours); volcanic origin **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Rhyolite, andesite, basalt (most Fe,Mg; least silica) **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Classification by texture and mineral composition **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Texture (grain size, shape, arrangement) **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Aphanitic – fine-grained, rapid cooling; generally extrusive **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Phaneritic – large-grained, slow cooling; generally intrusive **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Porphyritic – mineral grains of very different sizes; phenocrysts – large grains, groundmass – small grains; complex cooling histories **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Obsidian – no crystals because of rapid cooling **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Vesicular – small holes caused by trapped gases **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Pyroclastic/fragmental – formed by explosive eruptions; tuff is fine-grained, from ash; breccia is poorly sorted fine, large, angular from very violent eruptions **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Mineral composition **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Felsic (most silica) – rhyolite/granite **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Intermediate – andesite/diorite **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Mafic – basalt/gabbro **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Ultramafic (most Fe,Mg) – periodotite (olivine, pyroxene); makes up most of mantle **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Pegmatite – very large crystals, form in dikes or veins, usually felsic **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">(Monroe, Wiccander and Hazlett, pages 115-122) **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">DS **
 * Looks good! KMS**
 * Good MarkW**


 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Felsic (refers to __fel__dspar) **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">- Mafic – (refers to __ma__gnesium and __f__err__ic__ for iron) **
 * MarkW**

44. Sedimentary: classification methods, types, processes of formation, sedimentary structures, depositional environments, transgression and regression sequence
 * __Classification__**
 * **Detrital/Clastic Sedimentary Rocks- made of solid particles (gravel, sand, silt, clay). Classified primarily by size of** **constituent particles/clasts (conglomerate, breccias, sandstone, mudrocks).**
 * **Chemical Sedimentary Rocks- made of minerals derived from dissolved materials during chemical weathering.**
 * **Biochemical Sedimentary Rocks- made of minerals derived from chemical activities of organisms.**


 * __Types__**
 * Classified as: carbonate rocks (CO3)-2 (limestone and dolostone), evaporates (rock gypsum, rock salt), chert (microscopic quartz crystals), coal (biochemical/altered remains of land plants).**


 * Clastic characteristics- size (Wentworth size classification), well sorted (most grains same size, represents**
 * transport system energy, indicates distance of travel), poorly sorted (wide range of sizes), rounding (the more**
 * rounded the longer it’s been transported)**


 * __Processes of formation__**
 * detrital (clastic)- lithification (compaction, cementation)**
 * chemical- precipitation or biological accumulation (shells)**


 * __Sedimentary structures__**
 * **Cross bedding- layers arranged at an angle to the surface they accumulate on. Common in desert dunes, shallow marine environments and stream channels where wind or water flow in one direction. Form on the downwind/ downstream side of dune-like structure.**
 * **Graded bedding- grain size decreases upward within a single layer. Mostly from turbidity currents.**
 * **Ripple marks- small alternating ridges and troughs on sand dunes. __Current ripple marks__ form where water/wind** **flows in one direction over sand (asymmetrical). __Wave-formed__ __ripple marks__ form shallow, nearshore waters** **(symmetrical).**
 * **Mud cracks- form in clay-rich sediment that is drying**


 * __Depositional environments__**
 * **Continental- sand dunes, alluvial fans, lakes, glacial environments, stream environments**
 * **Transitional- beach, delta, tidal flat, lagoon**
 * **Marine- continental shelf, submarine fan, barrier island, deep marine environment**


 * Transgressive sequence- (fining upward) shoreline migrates landward, offshore facies deposited on top of**
 * nearshore facies over vast geographic area.**
 * Regressive sequence- (coarsening upward) opposite transgressive sequence**
 * Causes: seafloor spreading, addition or removal of water from oceans during glacial episodes.**


 * (Monroe, Wicander, Hazlett, pg 204-215)**
 * MarkW**

45. Weathering processes: chemical and physical, resulting products of weathering, including soil formation and soil types.
 * __Physical/Mechanical Weathering__**
 * **Frost wedging- water expands when frozen**
 * **Salt wedging- salt crystals grow over time**
 * **Expansive soil- soil expands when wet (clay)**
 * **Unloading- top load erodes, bottom rocks expand**
 * **Thermal expansion- heat expands rock from fire**
 * **Biologic activity- plant roots**


 * __Chemical Weathering (water always accompanies)__**
 * **Solution- dissolving NaCl to ions Na+ Cl- in water. Limestone dissolves to form caverns**
 * **Hydrolysis- feldspar plus water produces clay and ions (water only)**
 * **Oxidation- ferromagnesium silicates plus oxygen plus water produces an oxide (rust) and ions (water + oxygen)**


 * __Joints__****- cracks or fractures along which no movement has taken place**


 * __Bowen’s Reaction Series__**
 * **The minerals that come out of magma 1st at high temps tend to weather easily**
 * **The minerals that come out of magma last at low temps, quartz, tend to weather least**


 * Weathering products: ions in solution and physical particles (clasts)**


 * Soil: 45% minerals, 25% air, 25% water, 5% organic**


 * __Soil Formation Factors:__**
 * **Parent materials**
 * **Climate**
 * **Topography**
 * **Biological activity**
 * **Time**


 * __Soil Formation Processes:__** **(first 3 are main types)**
 * **Podzolization- (creates pedalfer soil) cool moist climate**
 * **Calcifcation (limestone)- (creates pedocal soil) dry climate**
 * **Laterization- (creates laterite soil) warm humid climate**
 * **Salinization**
 * **Gleization**


 * [ped=soil, fer= iron, al= aluminum, cal= calcite]**


 * (Monroe, Wicander, Hazlett p.170-190 and notes from Dr.Clary lecture) MarkW**

46. Metamorphic: agents of metamorphism, types of metamorphism, foliation, degrees of foliation
 * The principle agents of metamorphism are: heat, pressure, and fluid activity.**
 * The types of metamorphism are:**
 * Contact (thermal) – where a body of magma alters the surrounding country rock**
 * Dynamic – pressure-dominated recrystallization associated with fault zones in the shallow crust where rocks are subjected to concentrated high levels of differential pressure.**
 * Shock – shock waves from a large impacting meteorite radiate out through the crust with extreme pressures.**
 * Regional (most common) – occurs over a large area and is usually caused by high temperatures, pressures, and deformation all occurring together within the deeper portions of the crust.**


 * Foliated rocks show a parallel arrangement of platy minerals that produces a layered structure. Most foliated rocks are clay-rich or mafic in origin.**
 * Foliated rocks show an increase in average grain size with slates and phyllites being fine-grained, schists medium-grained, and gneisses coarse-grained (and also showing banding of light and dark minerals).**
 * Low-grade metamorphic rocks have a finely foliated texture with mineral grains so small that they cannot be seen without a microscope (slate, phyllite).**
 * High-grade metamorphic rocks are typically coarse-grained and mineral grains can be seen with the naked eye (gneiss, amphibolite, migmatite)**
 * Schist can be anywhere from low to high.**
 * KMS **
 * Good. Would only add: **
 * Nonfoliated - equigranular texture, such as marble, quartzite. **
 * DS **

47. Dating Principles: relative age and absolute age dating
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Relative dating methods determine the age of events relative to other events and place them in chronologic order without determining how long ago the events occurred. Absolute dating techniques (such as radiometric dating, carbon-14 dating, fission-track dating, and tree-ring dating) assign ages in years before present to geologic events. **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">DS **
 * Looks good. KMS**

48. Relative Age Dating: principles, types of unconformities, processes by which unconformities form
 * For the 6 principles of relative dating, see answer to #66. **
 * An __unconformity__ is a rock surface that represents a long period of time of either nondeposition, erosion, or both. Indicates “missing information” in the geologic record. **
 * Types of unconformities: **
 * __Disconformity__ – surface of erosion or nondeposition between younger and older sedimentary rocks which are parallel to one another; can be difficult to recognize without fossil assemblages **
 * __Angular unconformity__ – erosion surface on tilted or folded sedimentary rocks over which younger sedimentary rocks were deposited; lower strata are tilted more steeply **
 * __Nonconformity__ – erosion surface cut into metamorphic or igneous rocks which are covered by sedimentary rocks **
 * DS **
 * Looks good. **
 * JL **
 * Add nonconformity: may be covered by volcanic rock. I remember "nonconformity" by 'it takes a lof of pressure (metamorphic) to be a non conformist' **
 * LK **

49. Absolute (radiometric) Age Dating: primary assumption when using this method, data needed, basic parent-daughter isotope systems, calculations of rock ages
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Radiometric dating is based on the principle that unstable radioactive elements decay spontaneously into different, more stable elements. A __half-life__ of a radioactive element is the time it takes for one-half of the original unstable parent element to decay into a new more stable daughter elements. Half-lives for different radioactive elements range from less than a billionth of a second to 49 billions years. The half-life is constant and can be precisely measured. **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Three types of radioactive decay: **
 * **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Alpha – parent nucleus emits 2 protons and 2 neutrons **
 * **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Beta – parent nucleus emits electron **
 * **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Electron capture – proton captures electron and converts to neutron **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Radioactive decay occurs at a geometric rate (curved line). **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">In order to calculate age, you need to know the ratio of parent to daughter (determined by mass spectrometer) and the half-life of the parent **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Most accurate radiometric dates are obtained from igneous rock because the parents are separated from the daughters and incorporated into the crystal structure. **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Rarely can sedimentary rocks be radiometrically dated because one would be obtaining the date of crystallization of the grains, not when they were deposited to form a sedimentary rock. Sedimentary rocks with glauconite are an exception because glauconite can form during marine sedimentation. **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Primary assumption: Closed system – neither parent or daughter have been added/removed since crystallization. Fresh, unweathered samples are best. Heating or intense pressure may cause leakage. Therefore metamorphic rocks are also difficult to date **


 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Basic, long-lived parent-daughter systems: **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">__Isotope PairHalf-life Dating range__ **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">U238-Pb206 4.5 billion 10 million-4.6 billion **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">U235-Pb207 704 million **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Th232-Pb208 14 billion **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Rb87-Sr87 48.8 billion 10 million-4.6 billion **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">K40-Ar40 1.3 billion 100,000 to 4.6 billion **


 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Other methods: **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Fission track dating – process of counting number of small linear tracks that result when a mineral crystal is damaged by rapidly moving alpha particles generated by radioactive decay of uranium **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Carbon-14 dating – process that relies on determining ratio of C14 to C12 in an organic substance; dating range only back to about 70,000 years. **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">(Monroe, Wiccander and Hazlett, pages 281-286) **


 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Calculating ages: **
 * **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Graphical method: **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">By knowing the parent/daughter ratio, the number of half-lives elapsed can be determined from a graph. The number of half-lives can then be multiplied times the length of a half-life for the isotope pair to get the age of the mineral sample. **
 * **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Mathematical method: **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Decay rate, k = 0.693/T1/2 **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Age = ln ((daughter/parent) + 1) / k **
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">DS **
 * Very thorough! KMS**

50. Topographic maps: contour intervals, scales, Public Land Survey system, interpretation of topographic maps


 * Topographic Maps- 2-D representation on 3-D surface**
 * **__Contour lines__****- connect all points on map with same elevation above sea level**
 * **__Index contours__****- heavy contour lines with elevations printed on them**
 * **__Contour interval__****- distance between contour line**


 * Map Scales**
 * **Bar scale- land distance to map distance**
 * **Ratio scale- ratio of map distance to land distance**


 * Public Land Survey System**
 * **Uses Principal Meridians (N-S) and Base Lines (E-W)**
 * **Grids of 6 miles X 6 miles are created (N-S squares are townships/ E-W squares are ranges)**
 * **Townships can be divided into 36 smaller squares (1 mi2) and numbered 1-36 in an upper right to lower right winding pattern**
 * **Each section can be divided into NE, NW, SE, SW quadrants, which can be further subdivided**


 * //Only thing I would add is that the 1x1 square mile regions are called sections and consist of 640 acres~ great job JA//**

Interpretation of Topographic Maps (missing info…sorry)

//closed contours indicate peaks or regions of central elevation// //contours bend upstream// //slope = change in elevation over distance// //~JA//
 * (Notes from Geo 1 Lab 9) MarkW**

51. Plate tectonics: as a unifying theory, plate boundaries and variations of each type, features associated with each boundary type, identification of old boundaries in the field, volcanic activity, mountain building


 * __ Plate Tectonic Theory: __**** a unifying theory of geology because it explains the interactions between continents, ocean basins and mountain chains which affect oceanic and atmospheric circulation. Plate movement also influenced the distribution, evolution and extinction of plant and animal species. Furthermore, it explains the formation and distribution of many economically valuable resources. Alfred Wagener first proposed as continental drift in 1912. Lithosphere (solid upper mantle and crust) moves across asthenosphere (below upper mantle and flows like a fluid). **


 * __ Types of plate boundaries with associated landforms: __**
 * **__ Divergent __**** - continent/continent (creates rift valley); ocean/ocean (creates mid-ocean ridge); no continent/ocean. **
 * **__ Convergent __**** - continent/continent (mountains with minor volcanism), ocean/ocean (trenches and volcanic island arcs), continent/ocean (trenches and volcanic mountain chain) **
 * **__ Transform __**** - slide past each other horizontally (fault valley) **


 * Divergence (tensional stress on land) causes elongating and fracturing; ocean formation= divergent separation, faulting, linear sea, mid-ocean ridge (mature)**


 * Convergence (compressional stress on land) causes folding**


 * __Geologic Structures__**
 * Compressional- __folds__: monocline, anticline, syncline, dome, basin; __faults__: reverse**
 * Tensional- __faults__: normal (including horst and graben)**
 * Shear- __strike slip/transform__ (left and right lateral)**
 * __Joints__- broken rock but no offset (movement)**
 * __Strike and Dip__- strike is the horizontal orientation parallel to earth’s surface; dip is the angle**
 * the rock dips below horizontal**


 * Evidence for Plate Tectonics**
 * **Direct measurements of mountain growth, continental separation**
 * **Hot spots (stationary mantle plume used to determine plate movement)**
 * ** Fit of continents (Pangaea) **
 * ** Fossils **
 * ** Glacial striations **
 * ** Similarity of rock sequences and mountain ranges **

**(Monroe, Wicander, Hazlett p.16-62) MarkW**

52. Deformation: Types of stress, types of deformation (plastic and brittle), fold types, fault types,tectonic environments for each, **<span style="font-family: Arial,Helvetica,sans-serif;">There are three types of stress: 1) tensional (pulling apart) which occurs at divergent boundaries and intraplate where forces are pulling the plate apart; 2) compressional which occurs at convergent boundaries and intraplate where compressional forces are at work; 3) shearing (moving parallel in opposite directions) which occurs at transform boundaries. ** **<span style="font-family: Arial,Helvetica,sans-serif;">Once a rock under stress exceeds its elastic limit, it will undergo either plastic (ductile) deformation and fold, or brittle deformation and fracture. Which occurs depends on the following factors: 1) confining pressure; 2) confining temperature; 3) rock type; and 4) duration of stress. In short, surface rocks are more likely to fracture and fault and deeper rocks with high pressure and temperature are more likely to fold. ** **<span style="font-family: Arial,Helvetica,sans-serif;">Fold types are due to compressional forces: 1) anticline (like an arch, or “anthill”), 2) syncline (like a sink), and 3) monocline (step-like). May be symmetrical, assymetrical or overturned. **  **<span style="font-family: Arial,Helvetica,sans-serif;">Fault types are: two dip-slip faults: normal (FUN – __f__ootwall __u__p __n__ormal) which occurs under tensional stress (divergence) and results in the lengthening of crust; and reverse (or thrust, if angle <45 deg) (FDR – footwall down reverse) which occurs under compressional stress (convergence) and results in shortening of crust; and a strike-slip which occurs at transform boundaries (can be right or left lateral strike slip, as viewed from across fault) **  **<span style="font-family: Arial,Helvetica,sans-serif;">DS **  53. Earthquakes: mechanism, types of waves, effects, study of Earth’s interior, determination of epicenter
 * Good KMS**


 * __TYPES OF EARTHQUAKE WAVES__**
 * Earthquake shaking and damage is the result of three basic types of elastic waves. Two of the three propagate within a body of rock. The faster of these body waves is called the __primary or P wave__. Its motion is the same as that of a sound wave in that, as it spreads out, it alternately pushes (compresses) and pulls (dilates) the rock. These P waves are able to travel through both solid rock, such as granite mountains, and liquid material, such as volcanic magma or the water of the oceans.**
 * The slower wave through the body of rock is called the __secondary or S wave__. As an S wave propagates, it shears the rock sideways at right angles to the direction of travel. If a liquid is sheared sideways or twisted, it will not spring back, hence S waves cannot propagate in the liquid parts of the earth, such as oceans and lakes.**
 * The actual speed of P and S seismic waves depends on the density and elastic properties of the rocks and soil through which they pass. In most earthquakes, the P waves are felt first. The effect is similar to a sonic boom that bumps and rattles windows. Some seconds later, the S waves arrive with their up-and-down and side-to-side motion, shaking the ground surface vertically and horizontally. This is the wave motion that is so damaging to structures.**
 * The third general type of earthquake wave is called a __surface wave__, reason being is that its motion is restricted to near the ground surface. Such waves correspond to ripples of water that travel across a lake.**
 * Surface waves in earthquakes can be divided into two types. The first is called a __Love wave__. Its motion is essentially that of S waves that have no vertical displacement; it moves the ground from side to side in a horizontal plane but at right angles to the direction of propagation. The horizontal shaking of Love waves is particularly damaging to the foundations of structures. The second type of surface wave is known as a __Rayleigh wave__. Like rolling ocean waves, Rayleigh waves wave move both vertically and horizontally in a vertical plane pointed in the direction in which the waves are travelling.**
 * Surface waves travel more slowly than body waves (P and S); and of the two surface waves, Love waves generally travel faster than Rayleigh waves. Love waves (do not propagate through water) can effect surface water only insofar as the sides of lakes and ocean bays pushing water sideways like the sides of a vibrating tank, whereas Rayleigh waves, because of their vertical component of their motion can affect the bodies of water such as lakes.**
 * P and S waves have a characteristic which effects shaking: when they move through layers of rock in the crust, they are reflected or refracted at the interfaces between rock types. Whenever either wave is refracted or reflected, some of the energy of one type is converted to waves of the other type. A common example; a P wave travels upwards and strikes the bottom of a layer of alluvium, part of its energy will pass upward through the alluvium as a P wave and part will pass upward as the converted S-wave motion. Noting also that part of the energy will also be reflected back downward as P and S waves.**


 * MCA (Still need the mechanisms, effects, study of earth's interior and determination of epicenter)**

[] PB The **focal mechanism** of an earthquake describes the inelastic deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a **fault-plane solution**. Focal mechanisms are derived from a solution of the moment tensor for the earthquake, which itself is estimated by an analysis of observed seismic waveforms. The focal mechanism can be derived from observing the pattern of "first motions", that is, whether the first arriving P waves break up or down. This method was used before waveforms were recorded and analyzed digitally and this method is still used for earthquakes too small for easy moment tensor solution. Focal mechanisms are now mainly derived using semi-automatic analysis of the recorded waveforms. The Elastic Rebound Theory is an explanation for how energy is released during an earthquake. Elastic rebound is the mechanism by which energy is released during earthquakes. Rocks subjected to forces equivalent to those occurring in the crust initially change their shape. As more force is applied, however, they resist further deformation until their internal strength is exceeded. At that point, they break and snap back to their original undeformed shape, releasing internally stored energy. <span style="font-family: "Arial","sans-serif"; font-size: 13.33px;">The location within Earth’s lithosphere where fracturing begins and energy is first released is the earthquake’s focus or hypocenter. What is reported is the epicenter, or location directly above the focus. If the P-S time intervals are known from at least three seismograph stations, then the epicenter of any earthquake can be located. The difference in the arrival times of the P and S waves is a function of how far away the seismic station is from the earthquake. The greater the difference in arrival times, the farther away the seismic station is from the earthquake. By determining the distance each seismic station is from an earthquake using a time distance graph, seismologist draw a circle around each seismic station whose radius equals the distance the seismic station is from the earthquake. The point where all three circles intersect is the epicenter. <span style="font-family: "Arial","sans-serif"; font-size: 13.33px;">The destructive effects of earthquakes include ground shaking, fire, seismic sea waves, and landslides, as well as panic, disruption of vital services and psychological shock. <span style="font-family: "Arial","sans-serif"; font-size: 13.33px;">The geology of an area is a factor determining an earthquake’s destructiveness along with the time it strikes, population density, duration of the earthquake, its magnitude and the type of building construction. Types of soils are conducive to liquefaction such as loose sands and sediments. They will contain water between particles which will be shaken and dispelled upwards allowing the sediments to settle downward. This can produce a lagoon like area.
 * <span style="font-family: "Arial","sans-serif"; font-size: 13.33px;">Monroe, Wickander, Hazelett. Physical Geology 6th ed. Pg 302, 303, 309-310, Pg 314, 323 **

54. Ocean Basins: Types of margins (active versus passive), features of the ocean basin, reef systems


 * __ Passive Continental Margin __**** - broad cont. shelves, slope and rise with developed abyssal plains. Occur within a tectonic plate. **
 * __ Active Continental Margin __**** - ocean plate subducted beneath continental plate. No continental rise but an ocean trench. Continental shelf is narrow. Usually volcanoes, earthquakes and mountains. **


 * Ocean Basin Features: **
 * ** Mid-ocean ridges- a submarine mountain system composed of volcanic rock found in all the oceans (rift valley, rift mountains, sediment) **
 * ** Trenches- long narrow feature of active cont. margins along which subduction occurs **
 * ** Abyssal plains- vast, flat area on seafloor next to cont. rise of passive cont. margins **
 * ** Seamounts- submarine volcanic mountain at least 1 km above seafloor (pointed tip) **
 * ** Guyots- a flat topped (eroded by sea waves) seamount **
 * ** Reefs- moundlike, wave resistant structure composed of skeletons of organisms **


 * Reef Types **
 * 1) **__ Fringing __**** - solidly attached to margin of island or continent **
 * 2) **__ Barrier __**** - fringing reef except with a lagoon separating it from main land **
 * 3) **__ Atoll __**** - formed around subsided volcanic island with lagoon in middle **


 * (From Geo 1 notes) MarkW **

55. Mass Wasting: types of processes and products. 56. Geologic Agents: Ways in which modification occurs through erosion, transportation, deposition
 * Mass wasting can be classified by 1) rate of movement---from creep to very fast; 2) type of material and size of material--ie debris, rock, mud, ice; and 3) nature of the movement--fall, flow, or slide---slides can be translational (mass just shifting downslope) or rotational (scoop like motion) **
 * Controlling factors include the relief or angle; gravity which is the driving force; and water--mass wasting happens when surface tension of water holding particles together is overcome by too much more water, too fast (over saturation) **
 * LK **
 * Good. Would add: **
 * Triggers: changes in any of the controlling factors above, plus earthquakes, heavy rainfall, eruptions, explosions. **
 * DS **


 * Erosion is the removal of surface material from the Earth's crust and transportation of the eroded materials by natural agencies from the point of removal. Erosion is caused by wind action, river and stream processes, marine processes (sea waves), and glacial processes. The complementary actions of erosion and deposition or sedimentation operate through wind, moving water, and ice to alter existing landforms and create new landforms. Erosion will often occur after rock has been disintegrated or altered through weathering. Moving water is the most important natural agent of erosion. Sea wave erosion results primarily from the impact of waves striking the shore and the abrasive action of sand and pebbles agitated by wave action. Erosion by rivers is caused by the scouring action of the sediment-containing flowing water. Glacial erosion occurs by surface abrasion as the ice, embedded with debris, moves slowly over the ground accompanied by the plucking of rock from the surface. Wind plays a key role in arid regions as blowing sand breaks down rock and dislodges surface sand from unprotected sand dunes. Human intervention, as by the removal of natural vegetation for farming or grazing purposes, can lead to or accelerate erosion by wind and water.**


 * In geology, transportation refers to the movement of eroded debris, whether by rivers, glaciers, wind or ocean currents and tides. Particle sizes can vary from tiny clay particles suspended in moving water, to pebbles and boulders. As the particles are transported, their edges can be smoothed, and is described as rounding. Deposition occurs when the speed of movement of the transporting medium becomes insufficient to hold the particles. Examples of such deposits are: Bunter, Moraine, Overbank, Dunes, Tombolo.**


 * Deposition is the geological process whereby material is added to a landform. This is the process by which wind and water create a deposit, through the laying down of granular material that has been eroded and transported from another geographical location. Deposition occurs when the forces responsible for sediment transportation are no longer sufficient to overcome the forces of particle weight and friction, which resist motion. Deposition can also refer to the build up of a sediment from organically derived matter or chemical processes. For example, chalk is made up partly of the microscopic calcium carbonate skeletons of marine plankton, the deposition of which has induced chemical processes (diagenesis) to deposit further calcium carbonate.**


 * MCA**

57. Running water: fluvial systems, transportation methods, stream types, stages in development, drainage patterns, topographic controls on formation of drainage patterns


 * __Fluvial (river/stream) systems sediment transport:__**
 * - solution – dissolved ions**
 * - suspended – small particles**
 * - bed load – large particles, rolling, saltation**
 * __Stream types:__**
 * - straight – single channel in high elevation**
 * - braided – too much sediment load**
 * - meandering – single channel constantly trying to erode and deposit sediment**


 * __Stages in development:__**
 * - initial – straight stream channel (rapids)**
 * - intermediate – floodplain develops**
 * - advanced – wide floodplains with natural levee**


 * __Drainage patterns__****:**
 * - dendritic (looks like tree branches)**
 * - angular (joints and faults)**
 * - trellis (between two mountains meeting in the valley)**
 * - radial (down a volcano or dome)**
 * - annular (domes, basins)**
 * - deranged (no pattern)**
 * (from Geo 1 notes) MarkW**

58. Groundwater: typical profile, various zones, potential problems, dissolution processes and karst 59. Glaciers: formation of glacial ice, depositional and erosional features 60. Wind: erosional and depositional features in arid regions, controls on desertification
 * Monroe, Wickander, Hazelett. Physical Geology 6th ed. Pgs. 498-524 PB**
 * Groundwater is an important source of freshwater for agriculture, industry, and domestic use. It is the water that fills open spaces in rocks, sediments, and soil beneath the surface. It is one reservoir in the hydrologic cycle and accounts for about 22% of the world’s freshwater supply. Porosity is the percentage of a material’s total volume that is pore space. It is the spaces between particles in soil, sediments, and sedimentary rocks including cracks, fractures, joints, and faults. Permeability is the material’s ability to transmit fluids. It is dependent upon porosity and the size of the pores or fractures and their interconnections. Permeable layers that transport groundwater are called aquifers and materials that inhibit the flow of groundwater are called aquicludes. The water table is a surface separating the zone of aeration, which contains both air and water in its open spaces, and the underlying zone of saturation, in which all the pore space is filled with groundwater. The capillary fringe is a region where water moves upward from the base of the zone of saturation due to surface tension. The configuration of the water table is generally a subdued replica of the overlying surface topography, except in arid and semiarid regions where it is usually flat regardless of the overlying land surface. Groundwater moves downward under the influence of gravity. It moves through the zone of aeration to the zone of saturation. Some of it then moves along the slope of the water table, while the rest moves through the zone of saturation from areas of high pressure to low pressure. Groundwater velocity varies and depends on different factors. It averages a few centimeters a day. A spring is a place where groundwater flows or seeps out of the ground. A water well is an opening made by digging into the zone of saturation. A cone of depression forms around a well when the rate of water drawn from the well is greater than the rate of water inflow to the well, lowering the water table around the well. Three geologic factors need to be present for an artesian system to develop. The aquifer must be confined above and below by aquicludes, the rock sequence is usually tilted and expose at the surface so the aquifer can recharge, and precipitation in the recharge area is enough to keep the aquifer filled. Sinkholes are depressions in the ground that form by the dissolution of the underlying soluble rocks (limestone) or when a cave’s roof collapses. Karst topography develops largely by groundwater erosion in areas underlain by soluble rocks. Features characteristic of karst topography include sinkholes, solution valleys, disappearing streams, springs, and caves. Caves form when groundwater in the zone of saturation weathers and erodes soluble rock. Modifications to the groundwater system can cause lowering of the water table, saltwater incursion (caused by excessive pumping of groundwater in coastal areas), subsidence (when excessive amounts of groundwater are withdrawn from poorly consolidated sediments and rocks causing the reduction of the water pressure between the sediments and rocks and the weight of the grains become packed more tightly to close up the spaces between them causing the surface to sink downward), and contamination (contaminants seep into the ground percolating into the zone of aeration and then into the zone of saturation or entering the water system directly through means such as sewer discharge into water bodies).**
 * Monroe, Wickander, Hazelett. Physical Geology 6th ed. Pgs. 536-553 PB**
 * Ice is a crystalline solid with characteristic physical properties and a specific chemical composition and therefore is a mineral. Glacial ice is a type of metamorphic rock, but one that is easily deformed. Glaciers form in any area where more snow falls than melts during the warmer seasons and a net accumulation takes place. The behavior of a glacier depends on its glacial budget, which is the relationship between accumulation and wastage. A budget may be balanced, negative or positive. The upper part of a valley glacier is its zone of accumulation (additions exceed loses) and the lower part of the glacier is its zone of wastage, where losses from melting sublimation, and calving exceed the rate of accumulation. Glaciers move at different rates depending on slope, discharge, and season. Valley glaciers tend to move faster than continental glaciers. At times glaciers move very quickly, as much as tens of meter per day during surges. Glaciers are solids in motion that erode by bulldozing, plucking, and abrasion, and they transport and deposit large amounts of soil and sediment. Valley glaciers transport sediment in all parts of the ice and continental glaciers carry most of their sediment in the lower part of the ice. Erosion of mountains by valley glaciers produces cirques, arêtes, and horns which are sharp, angular landforms; also, u shaped glacial troughs, fiords, and hanging valleys. Continental glaciers abrade and bevel high areas, forming a smooth rounded landscape known as an ice scoured plain. Glacial drift applies to all deposits of glaciers particularly till and stratified drift. Ridgelike accumulations of till called moraines are terminal (marked the greatest extent of the glaciers), recessional (ice front has receded), lateral (transported sediment deposited as long ridges of till), or medial (the merging of tow lateral moraines as when a tributary flows into a larger glacier), depending upon their positions. Drumlins are also composed of till that was shaped into streamlined hills by glaciers or by floods of glacial meltwater. Stratified drift is sediment deposited by meltwater streams as outwash plains adjacent to continental glaciers, or valley trains near valley glaciers. Ridges called eskers and conical hills known as kames are also made up of stratified drift. Deposits in glacial lakes consist of dark and light couplets of fine grained sediment called varves.**
 * Sediments are transported in deserts by flash floods or wind. Floods lead to arroyos, alluvial fans, playa lakes, erosional effects of combo wind and water like plateaus, mesas and buttes. **
 * Wind erosion can cause ventifacts (carved and moved rocks) deflation of solid (excavated pits by wind) and depositional features like loess deposits and various dune forms. **
 * Controls of desertification include Planting dry climate plants, not cutting trees and plants as their root systems are very slow growing and anchor soils. Not plowing for farming also decreases wind erosion. **
 * LK/ Good MarkW **


 * Would like to add (some are redundant but added for clarity):**
 * **Ventifacts- products of wind abrasion; polished, pitted, grooved rocks**
 * **Yardangs- larger than ventifact, looks like overturned ship’s hull**
 * **Deflation- excavated of loose surface sediment by wind to form deflation hollows**
 * **Desert pavement- after deflation removes loose, fine-grained particles, a concentration of larger particles become compacted and create a protective layer that prevents further erosion**
 * MarkW**

61. Coastal processes: distinguish between tides, waves, and shoreline currents;erosional and depositional landforms, emergent and submergent coastlines and associated landforms.


 * __Tides__: 2 high tides/day (flood tide) and 2 low tides/day (ebb tide). From 2 tidal bulges; lunar tidal bulge and the other on the opposite side of earth due to centrifugal force. Spring tides- (highest high and lowest low tides) when the moon and sun align every 2 weeks, full and new moon. Neap tides- (moderated high and low tides) when sun and moon are at right angles, 1st and 3rd quarter moon. Tides impact shorelines because area of wave attack constantly shifts from onshore to offshore.**


 * __Waves__: Highest part of a wave = crest; low point between crests = trough; distance between successive crests (or troughs) = wavelength; vertical distance between crest and trough = wave height; time required for 2 successive wave crests to pass a given point = wave period.**
 * **Water in waves has little or no net forward movement. The water particles rotate in circular orbits and transfer energy in the direction of wave advance. The diameter of the orbits diminishes rapidly with depth and reach zero at one-half wavelength (called wave base.)**
 * **Wave size depends of 3 wind factors: how fast (speed), how long it blows (duration) and size of area over which wind blows (fetch).**
 * **When wind generated waves reach nearshore water shallower than wave base the waves “feel” the bottom and wavelength decreases, wave height increases and the waves become oversteepened and plunge forward as breakers.**
 * **Most of the geologic work on shorelines is done by wind generated waves, especially storm waves.**


 * __Shoreline currents:__**
 * __Longshore currents__- because waves hit a shoreline at some angle, they generate longshore currents that flow parallel to the shoreline. These are particularly important because they transport and deposit large quantities of sediment in the nearshore zone (longshore drift).**
 * __Rip currents__- excess water along a shoreline returns to the open sea in rip currents that carry water seaward through the breaker zone.**


 * __Erosional Landforms/Emergent Shoreline__**
 * **__beaches-__ lacking or small, discontinuous and restricted to protected areas (pocket beaches)**
 * **__sea cliffs__**
 * **__marine terraces-__ wave-cut platforms elevated above sea level.**
 * **__wave-cut platforms-__ formed from undercutting sea cliffs by hydrolic wave action, abrasion and corrosion**
 * **__sea caves-__ formed when more resistant rock in the sea cliffs form seaward-projecting headlands. Less resistant surrounding rock erodes forming caves due to wave refraction around the headlands.**
 * **__sea arch-__ forms when sea caves on opposite side of headlands connect**
 * **__sea stack-__ when continued erosion on the wave-cut platform causes the sea arch to collapse**


 * __Depositional Landforms/Submergent Shoreline__**
 * **__beaches__- deposits of sediment by waves and longshore drift (by longshore currents)**
 * **__spits__- a fingerlike projection of a beach into a body of water such as a bay**
 * **__bars__- a spit that has grown until it completely closes off a bay from the open sea**
 * **__bays__**
 * **__lagoons__- body of water between barrier island and mainland**
 * **__tombolo__- a spit that connects a sea stack to the mainland**
 * **__barrier island__- parallel to shore, long and narrow, separated from shore by lagoon**


 * (Monroe, Wicander, Hazlett p.598-615) MarkW**
 * I would like to add that there is a fine distinction between erosional/depositional vs. emergent/submergent. Erosional/depositional has to do with sediment erosion, transport and deposition whereas emergent/submergent has to do with changing sea levels. Submerged coasts are "drowned" and form estuaries. Emergent coasts are found where the land has risen with respect to sea level and have marine terraces as distinctive features.**
 * -PM**

62. Deserts and wind: sediment transport by wind, wind erosion, wind deposits, desert landforms
 * Deserts are defined as areas receiving less than 25 cm rainfall/year. They are often located in areas of sinking dry air (30 degree latitude and poles); in rain shadows of mountain ranges; far from oceans; or next to cold ocean currents. **
 * Sediments are transported in deserts by flash floods or wind. Floods lead to arroyos, alluvial fans, playa lakes, erosional effects of combo wind and water like plateaus, mesas and buttes. **
 * LK **