Quick Summaries
"Must Know Info..."

 
SURFACE PROCESSES - QUICK SUMMARY

Weathering and Erosion
· Weathering - the breakdown of rock in place. 
· Erosion - the transport of rock by wind, water, or ice. 
· Physical (mechanical) weathering- physical breakdown of rock without chemical change (e.g. ice wedging, exfoliation).
· Chemical weathering - breakdown of rock caused by chemical reactions with the minerals (e.g. acid rain dissolution, iron oxidation to rust).
· Biological weathering - breakdown caused by living organisms, both physical and chemical (e.g. acids produced by organic decay, root wedging).
· Bowen's Reaction Series order of mineral crystallization is opposite the order of susceptibility to chemical weathering. Olivine breaks down most easily; quartz is most stable.
· Mass wasting - downslope movement of rock material and soil caused by heavy rainfall or earthquake activity; many types and speeds of travel.
· Mass wasting can be controlled by planting vegetation on slopes, dewatering slopes, building retaining walls and barriers, etc.

Running Water
· Load - the material carried by a stream.
· Bedload - the sediment rolled along the stream bottom. Suspended Load - the sediment carried in suspension. Solution Load - the sediment (e.g. elements and compounds) dissolved in the water.
· Sorting by sediment size occurs in a stream according to the speed of the water. e.g. If a stream slows down locally, some of the coarsest sediment will stop being transported as bedload and be deposited.
· Erosion and deposition are greater when the stream carries a greater load, moves faster (e.g. along a steeper gradient), discharges more water, and/or there are more erodible sediments in the channel.
· Meanders have erosion on the outside of the curve and deposition along the inside.
· Water transported particles are most likely to be: round, smooth (physically mature), chemically mature, fine to medium-grained, and well-sorted.
· Wind transported particles are likely to be: well-rounded, pit-marked, chemically immature, very fine grained, and very well-sorted.

Glaciers
1. Erosional Features
· U-shaped valley - a valley generated by glacial erosion.
· Hanging valley - a valley formed by a tributary valley glacier feeding into a larger valley glacier. Cirque - a bowl-shaped excavation at the head of an alpine glacier.
· Horn - a multi-sided mountain peak formed by three or more glaciers.
· Arete - an erosional remnant ridge between two, parallel valley glaciers or adjacent cirques. Striations - scratch marks on bedrock made by rock debris carried in a glacier.

2. Depositional Features
· Erratic - a large rock deposited by a glacier. Moraine - till deposited by a glacier
· Ground Moraine - hummocky till layer deposited at the base of a receding glacier Terminal Moraine - till mound deposited at the front edge of a glacier at its farthest extent Recessional Moraine - till mound deposited at the front edge of a glacier during a standstill as it recedes
· Lateral Moraine - till mound deposited at the edge of a glacier
· Medial Moraine - till mound deposited at the boundary of two (valley) glaciers as they recede Kame Terrace - sediments deposited in meltwater lakes along the edge of a glacier
· Esker - stratified sands and gravels deposited by a stream on or in a glacier; identified on a glaciated landscape as a sinuous ridge.

Ground Water
· The water table is the top of the Zone of Saturation where all pore space is filled with water. Above it lies the Zone of Aeration where pores are partly filled with water and air.
· A perched water table lies above the regional water table in places where impermeable rock, such a layer of shale, acts as a barrier trapping water above it.
· A confined water table is overlain and underlain by impermeable rocks. It is the source of artesian water wells.
· An aquifer is a body of rock capable of holding groundwater because of great porosity and permeability, such as sandstone.
· Porosity is a measure of the volume (abundance) of holes in a rock. The greater the porosity the more water that can be held.
· Permeability is a measure of the interconnectedness of the pores. The greater the permeability, the more readily water can move through a rock.

 
MINERALS - QUICK SUMMARY 
Silicates
Silicates are a class of minerals that make up most of the Earth's crust. (Oxygen makes up 46.6% and silicon makes up 27.7% of the crust.) They include all common rock forming minerals, i.e. all those in Bowen's Reaction Series, and many, many more.

Definitions of Mineral Properties
· Cleavage -breaks along one or more flat planes Fracture - does not break along flat planes, rather along irregular surfaces Hardness - resistance to scratching (not to breaking; mineral may be brittle) Specific gravity - similar to density, a measure of how heavy a mineral is relative to its size Colour - as seen in regular daylight, it is a property that may vary for one mineral
· Streak - colour of the mineral powder, a property that does not vary for a mineral
· Lustre - the way a mineral reflects light, metallic (like a metal) or nonmetallic, which includes vitreous (glassy), earthy, pearly, dull, adamantine, etc. Metallic minerals generally have a dark streak; nonmetallic minerals generally have a light coloured streak.
· Special Properties - magnetism, e.g. magnetite
· reaction with acid e.g. calcite and other carbonates double refraction, e.g. calcite
· fluorescence, fluorite
· salty taste, e.g. halite, sylvite radioactivity, e.g. K-feldspar, uraninite

Common Minerals
· Quartz - hexagonal prismatic crystals, conchoidal fracture, hardest common mineral (H=7), many colours, framework silicate, vitreous
· Mica - muscovite (light) and biotite (dark) the most common, common in metamorphic rocks (lines up under pressure creating foliation), sheet silicates, vitreous 
· Garnet - metamorphic formation from some shales, hard (H=7), red (and other colours), semi-precious gemstone, vitreous
· Asbestos - metamorphic formation from ultramafic rocks, a good insulator, carcinogenic
· Hematite - comes in several colours, but always has a reddish-brown streak
· Galena - very dense, metallic, cubic crystal structure
· Pyrite - Fool's Gold, metallic, commonly associated with gold, source of acid rock drainage 
· Chalcopyrite - metallic, mined for copper, less dense than real gold
· Bornite - peacock ore, metallic, mined for copper
· Graphite - metamorphic origin, high temperature lubricant, pencil lead
· Gold - native element, unattached to other elements, very high density
· Fluorite - cubic crystals, cleaves octahedrally, purple and green common, vitreous

 
RESOURCES - QUICK SUMMARY

Economic minerals:
· are profitable to mine 
· mining requires assurance of environmental protection
· must be adequately concentrated and in great enoughvolume
· mining depends on supply and demand and value (selling price)
· mining requires physical accessibility Magmatic Deposits

Types of Deposits
· Kimberlite - isolated ultramafic pipes of magma from the mantle bearing diamonds 
· Fractional crystallization - accumulations of mineral crystals that settle to the bottom of magma chamber, e.g. chromite and magnetite
· Pegmatite - very coarsely crystalline rock commonly formed from residual magma with higher concentrations of rare elements - e.g. lithium, boron, uranium
· Hydrothermal - minerals precipitated from hot, metalliferous fluids that have escaped from cooling magma (or groundwater heated by adjacent magma), commonly sulfide ore or native elements, e.g. copper, lead, zinc, gold, silver, platinum, uranium
· Magmatic activity commonly occurs along plate boundaries, so mineral deposits are commonly found along ancient boundaries.

Minerals and Metals of Value (see table provided in class)

Metal / Common Ore Minerals
Aluminum / Bauxite 
Copper / Chalcopyrite and Chalcocite and Bornite 
Lead / Galena 
Mercury / Cinnabar 
Molybdenum / Molybdenite 
Nickel / Pentlandite and laterites
Tin / Cassiterite 
Zinc / Sphalerite 

Energy “Minerals” = Coal, oil, gas and uranium
Gemstones = Diamonds, rubies etc
Industrial Minerals = Salt, limestone, marble etc

Formation of Natural Gas and Oil
· Oil and gas formation take time. 
· No petroleum is found in rocks younger than 1 to 2 million years old.
· Numerous marine organisms that live in the water column, and are rich in carbon and hydrogen, settle out onto sea floor when they die. They are rapidly buried by sediment, so the organic tissues do not decay. Burial is accompanied by an increase in P and T which slowly, over time, causes chemical reactions that break down the large complex organic molecules into simpler hydrocarbon molecules. As breakdown continues large thick hydrocarbons become progressively smaller and thinner until, finally, very simple, light, gaseous molecules (natural gas) are formed. This process mostly occurs between 50 - 100° C. At higher T methane (CH4) forms. 
· Porosity - the volume of pore space in a rock.
· Permeability - the interconnectedness of pore space in a rock . A good oil reservoir has high porosity and high permeability.
· Oil traps - porous and permeable reservoir rock with an impermeable cap rock that prevents the oil/gas from migrating to the surface. See examples on pg 446 in text.

Coal
· Coal is the remains of land plants that have fallen into and accumulated in a tropical swamp. 
· Stages of Coal Formation (see Figure 21.8 pg 451)
     peat > lignite > sub-bituminous > bituminous > anthracite
     low heat, low carbon >>>>> high heat, high carbon
     softer >>>>>>>>>> harder
· The higher the T and P, and longer the time, the harder and higher heat coal is produced.
· If the burial T is too high, the organic tissues metamorphose; graphite is formed. (Graphite does not burn.)

Methods of Exploration
· Gravitational survey, look for gravitational high
· Magnetic survey, look for magnetic high
· Soil sample geochemical analysis
· Mapping bedrock geology and interpreting history
· Drilling and coring
· Drilling and geophysical logging

Placer Deposits

What are they? The erosion of weathered rocks and minerals results in the tougher, heavier material staying behind as the less resistant material moves away. When the conditions are right, valuable minerals can concentrate to form placer deposits. 

Where the rocks and minerals are exposed to the elements at the surface the vein or rock in broken down, forming soils and concentrations of valuable minerals called placers. Gravity, rain, snow, and wind aid in the movement of the soil downslope, further concentrating of the valuable minerals forming eluvial placer deposits in the rivulets and gulleys.

As the soils work their way down hill into washes and stream channels, water plays a more important part in the continued concentration of the valuable minerals within them. The deposits will form where the water slows or around obstructions in the channel. If the channels were formed in ancient times, the placer deposits may occupy benches elevated well above the present day stream channel.

Examples: gold, tin, platinum (all were originally hydrothermal vein deposits)

 
ROCKS - QUICK SUMMARY 

Rock Cycle
· One rock type can change into another type by natural, physical and chemical forces acting on it. Igneous rocks form from the melting of pre-existing rocks and solidification of that magma. Sedimentary rocks form from the weathering and erosion of pre-existing rocks, deposition and lithification. Metamorphic rocks form by the application of heat and/or pressure to, or by chemical reactions in pre-existing rocks.

Igneous Rocks
· If magma cools slowly (intrusive/plutonic), there is more time for large crystals to grow.
· If magma is thin (i.e. runny), it is easier for large crystals to form.
· If magma cools quickly (extrusive/volcanic), a glassy and/or frothy (vesicular) texture may result.
· Magma near the surface is under less pressure, so gas dissolved in it can "undissolve" and to form bubbles in the magma.
· Pyroclastic textures result from explosive volcanic eruptions.
· A porphyry has two crystal sizes that record two cooling stages of the magma.
· Felsic magma is viscous (thick) and light-coloured, has a relatively low density, erupts explosively due to trapped gases, is extruded as rhyolite and intruded as granite, and forms composite volcanoes.
· Intermediate magma has properties similar to felsic magma, but is extruded as andesite and intruded as diorite.
· Mafic magma is thin (relatively runny) but dense, is very high temperature, erupts in relatively smooth flows to form gently-sloping shield volcanoes, and is extruded as basalt and intruded as gabbro.
· Intrusive features include: sill (parallel), dike (cross-cutting), xenolith (unmelted fragment of country rock)
· Obsidian: glassy, has cooled very quickly, exhibits conchoidal fracture and is generally felsic in composition.
· Pumice: vesicular, cooled quickly from an explosively erupted frothy magma, and floats on water. 
· Pegmatite: very coarsely-crystalline intrusion that formed from a thin (runny), very slowly cooled magma.
· Tuff: volcanic ash glued together.

Bowen's Reaction Series explains the order in which mineral crystals form from in a melt as it cools. Olivine forms first; quartz forms last.

Be able to use the Minerals in Igneous Rocks chart to identify unknown rock samples by the percentage of minerals present and to identify compositionally equivalent rocks.


Sedimentary Rocks
· The further sediment has been transported, the more physically mature it will be.
· The longer sediment is in contact with water, the more chemically mature it will be. 
· Clastic - made of broken rock or mineral grains glued together (lithified). e.g. conglomerate (coarsest), sandstone, shale (finest), breccia (angular)
· Chemical - precipitated from solution, crystals may be visible e.g. limestone (CaCO3), chert (SiO4), evaporites (gypsum, halite)
· Stratification - layering in a sediment or sedimentary rock
· Cross-bedding - inclined stratification deposited by big ripples moving in water or air
· Ripple marks - asymmetrical in flowing water (e.g. streams), symmetrical in waves (e.g. beach, lake)
· Mud cracks - V-shaped structures that form in fine-grained sediments that have dried up. They are widest at the top.
· Graded bedding - decrease in grain size up through a bed caused by rapid settling of sediment suspended in a turbulent flow (e.g. turbidite)
· Varves - annual layers of fine sediment deposited on a glacial lake bottom

Metamorphic Rocks
· Pre-existing rocks are changed by heat and/or pressure and/or chemical reactions into other types of rocks.
· Shale (sedimentary) > Slate (micas line up under P causing some foliation) > Phyllite (more foliation) > Schist (more foliation, mica more visible) > Gneiss (under greater pressure, under certain conditions)
· Granite (igneous) > Gneiss (compositional banding)
· Conglomerate (sedimentary) > Meta-conglomerate (stretched pebbles, break across pebble)
· Limestone (sedimentary) > Marble (coarser crystals)
· Sandstone (sedimentary) > Quartzite (recrystallized quartz grains)
· Foliation - planar structure in a metamorphic rock caused by parallel alignment of linear or planar minerals (as seen in slate, phyllite, schist, and gneiss)
· Non-foliated - rock texture consisting predominantly of equidimensional grains (e.g. quartzite, marble)
· Compositional banding - metamorphic foliation caused by recrystallization of minerals in the rock segregate into bands of differing composition or texture.
· Contact metamorphism - changes in country rock caused by the heat of a nearby intrusion. Regional metamorphism - high T and P changes to bedrock over a large area due to deep burial or tectonic collision.
· Chill margin - edge of an intrusion with relatively fine crystal size caused by rapid cooling of magma adjacent to the country rock.

 
GEOLOGIC TIME - QUICK SUMMARY

Relative Age Dating - put geologic events in order by considering these principles. 
· Faunal succession - No life form is exactly duplicated at another point in time. 
· Uniformitarianism - "The present is the key to the past."
· Original horizontality - Sediments are deposited in flat-laying layers.
· Cross-cutting relations - A fault or dike that cuts across layers is younger than the layers. Correlation - Two rocks containing the same fossil must be the same age.
· Superposition - If undisturbed, the oldest layer is on the bottom, the youngest is at the top. Included fragments - Pieces of rock (xenoliths or intraclasts) in a rock are older than the rock they are in.
· Unconformity - a break in the rock record due to erosion or nondeposition. Angular unconformity: layers above and below are not parallel. Disconformity: layers above and below are parallel.

Absolute Age Dating - find a numerical age for a rock by radiometric dating techniques, counting tree rings or varves, or using index fossils.
· Radiometric Dating: Half-life - the length of time for half a radioactive parent sample to decay and become a stable daughter. It is unique for each radioactive isotope. It never changes.
· When an igneous rock forms, it contains an amount of parent isotope. That isotope instantaneously starts to spontaneously decay to form daughter isotopes. Scientists (geochronologists) can measure the amount of parent and daughter isotopes in a rock sample and determine how many half-lives have passed. The age of the sample is calculated:

Age = (# of half-lives) X (length of half-life)

Sources of Error in Radiometric Dating
· Daughter isotope may have been present when the rock formed, so the sample will appear older.
· Daughter isotopes may have escaped from the rock (e.g. argon gas), so the sample will yield a younger age.
· Some parent/daughter isotopes may have been added to the sample, so the sample will yield a younger or older age, respectively.
· Scientists can correct for possible errors by using more than one radiometric isotope and comparing the ages obtained.
· Numerical age ranges for sedimentary rocks can be obtained by radiometric dating sills, dikes, or lava flows which underlie, overlie or intrude them.
· Carbon 14 has a short half-life (5730 years) and is predominantly used to date organic material. 

Geologic Time Scale
Review the events written on the geologic time scale. 

Fossils
· A fossil is a replica of an organism. 
· Hard parts preserve most easily. 
· Generally fossilized in water where most sediments accumulate.
· Rapid burial required to prevent scavenging and decay (i.e. seal from oxygen and bacteria). Fossilization of soft parts (a replica, not the soft parts themselves) requires that the entire organism must be buried shortly after death in deep, low-oxygenated water.
· A trace fossil is a sedimentary structure made by an organism such as a footprint, burrow, or feces. Methods of Fossilization
· Original preservation - original skeletal material or soft tissues remain e.g. frozen wooly mammoth
· Carbonization - a "picture" in carbon; common plant fossilization method Replacement - a mineral (e.g. quartz) takes the place of the original structure Permineralization - a mineral fills in the pore spaces of the original structure Mold - sediments solidify around the shell, water flowing through dissolves the shell, and the hollow remaining shows the external features of the shell
· Cast - sediments fill in the mold and show only the external features of the shell, no internal structure is present
· An index fossil is one that is especially useful in correlating strata. It may be a plant or animal that was short-lived, was geographically widespread and abundant, and is easily identified.

Review the fossil phyla. You must be able to recognize the phyla, know where and how they lived, approximately when and what are the living relatives if any.

Evolution
· Punctuated equilibrium - a model for evolution that predicts that life forms remain unchanged for long periods of time and then, suddenly, undergo a major change followed by a long period of stability.
· Adaptive radiation - animals adapt to the environment they are in and, consequently, are different from their parents. (e.g. Darwin’s finches)
· Natural selection - a principle of the theory of evolution: survival of the fittest.

 
INTERNAL PROCESSES AND STRUCTURES - QUICK SUMMARY 

Evidence For Plate Motion
· Earthquakes 
· Volcanoes 
· Tropical fossils in northern climates, glacial features at the Equator, seashell fossils on mountain tops
· Polar wandering curve
· Magnetic stripes on the seafloor 
· Magnetic stripes record polarity reversals. 
· Seafloor Spreading - Plates separate as magma rises up from the mantle. Youngest rocks are along the ridge; oldest are furthest away.

Plate Boundaries and Associated Volcanics
· Converging - two plates collide. 
· Subduction occurs between oceanic plate and oceanic or continental plate. 
· Composite volcanoes (explosive, andesitic, layers) form above the boundary. 
· Mountains are uplifted at continent-continent collisions. 
· Compressional forces generate folds and reverse and thrust faulting.
· Diverging - two plates separate (e.g. Mid-Atlantic Ridge, Juan de Fuca Ridge). Characterized by tensional forces, normal faulting, newly-created crust, smooth flowing flood basalts. Transform - two plates move horizontally past each other (e.g. San Andreas Fault). Characterized by a shearing force, strike-slip faults, and no addition or reduction in crust.

Around the World
· Himalayans (N. India) and Alps (N. Italy) - formed by collision between two continents.
· Andes (South America) and Cascades (U. S.) - volcanic chains formed on continental crust above subduction zones.
· Appalachians and Cordilleran (North America) - formed by the collision of micro-continents and volcanic island arcs with the margins of the continent.
· Aleutians (Alaska) and Japan - volcanic islands formed above a subduction zone between oceanic plates.

Cause of Plate Motion
· Convection currents in the asthenosphere drag the plates along or/and gravity pulls on cool plates being subducted.
· Origin of Magma
The temperature of the Earth gets hotter with depth (geothermal gradient) at a rate of 30°C/km. It is hot enough in the upper mantle (50-250 km) to melt rock. Different minerals melt at different temperatures. More heat is required to melt rock under great pressure.
· Isostatic Adjustment
· The crust adjusts up and down as it floats on the mantle. If a load is removed, as with a melting glacier, it moves up; if a load is added, as with formation of a volcano, it subsides. Volcanic Features

Volcanic Features
· Hotspot - a stationary plume of magma that rises and breaks through a lithospheric plate. The plate moves and eventually the magma comes through at a different location on the plate. Shield volcanoes form (basaltic, smooth-flowing, low and wide outline) .
· Columnar joints - fractures that form as magma (generally basaltic or andesitic) cools and contracts into polygonal columns perpendicular to the cooling surfaces.
· Volcanic dome -lava mound that forms when viscous magma (felsic) oozes out, like toothpaste, and piles up near the vent.
· Lava plateau - upland formed by flood basalts on a continent.
· Nuee ardente - a hot, fast, ash flow that burns everything in its path as it travels down the side of a volcano; commonly associated with andesitic volcanism.
· Pillow lava - basaltic lava extruded under water where it forms bulbous pillows with glassy crusts and coarser crystals inside.
· Aa lava - slightly cooled and so thicker, basaltic lava that breaks into sharp, blocky chunks as it flows; hard to walk on.
· Pahoehoe lava - a basaltic lava flow that develops a wrinkled, ropy surface as the flow underneath continues to move.

Plutonic Features
· Batholith - a large, complex intrusion of numerous plutons. 
· Stock - a small intrusion.
· Sill - an intrusion between parallel layers of sediment (or pre-existing flows). 
· Dike - an intrusion that cross-cuts pre-existing rock layers or rock body. 
· Xenolith - fragment of unmelted country rock in magma.

Relationship of the Rock Cycle to Plate Tectonics

· Where magma is generated (diverging plates or subduction zones) igneous rocks form. 
· Where plates collide, metamorphic rocks form. 
· Where rock is exposed and weathered, or shelly creatures thrive, sediment is formed, transported and deposited on the Earth's surface. 
· The composition of the sediment reflects the source terrane. 
· Earthquakes
· Creep - plates slowly move past each other; no build up of pressure.

Evidence of a Layered Earth

· Seismic waves speed up at the Moho (between the crust and mantle).
· S waves disappear at the outer core (liquid).
· Seismic waves refract (bend) at boundaries.
· Some P waves reflect at the inner core (denser)

Cross-section of the Earth (see diagram provided in class)
Know the following:
A - atmosphere, 80 km, 78% N, 21 % O, 1 % other
B - ocean, average depth 4 km, deepest 11 km (Marianas Trench), water 
C - oceanic crust, 10 km thick basalt
D - continental crust, 5O+km thick, granitic (average) 
E - lithosphere, 50-100 km thick, solid
F - asthenosphere, to 500 km thick, solid, but plastic
G - mantle, base of crust to 2900 km, silica and ferromagnesians 
H - outer core, 2900 to 5000 km, liquid
I - inner core, 5000 to 6370 km, solid
J - core, 2900 to 6370 km, iron and nickel

Moho seismic discontinuity - between D (continental crust) and G (mantle)

· Whether a rock behaves plasticly (i.e. changes in shape permanently) or brittly (i.e. breaks) depends on temperature (high = more plastic), confining pressure (higher = more plastic) and the intrinsic characteristics of the rock.
· Elastic rebound - plates continue to move slowly and deform, but are frozen along the actual boundary. Pressure builds until the jam breaks and the plates move back into their original shapes in offset positions.
· Magnitude - a measure of ground motion (up by factors of 10) and energy release (up by factors of 30). Measured with the Richter Scale which has no maximum value.
· Intensity - a measure of earthquake damage. Based on the Mercalli Scale in which total destruction is 12.
· Epicentre location can be determined by measuring the difference in arrival times of P (faster) and S waves at three seismograph stations, referring to a Time-Distance graph to determine how far away the earthquake occurred from each station, and drawing great circles with radii equal to each distance to see where they intersect. 

Seismic Risks
· Geographic location: e.g. if you live near an active plate boundary
· Topography: e.g. if you live next to a mountain face that will slide during an earthquake. 
· Ground strength: e.g. bedrock is more stable than sediments
· Proximity to faults: the further away, the better
· Construction design: difficult to do using scale models; specifications always change 

Earthquake Prediction
· Dilatancy data: the amount of water pore spaces, lubricates fault surfaces, affects water table levels.
· Seismic gaps: area along an active fault that has not moved in a long time. 
· Animal behaviour: dogs and cats go astray.
· Land rising: caused by pressure buildup along a fault.

Structures
· Fault - break in rock along which there is movement. 
· Joint - fracture in rock along which there is no movement. 
· Dip-Slip Fault (vertical movement)
· Normal Fault - tensional forces (e.g. divergent plates)
· Reverse Fault - compressional forces (e.g. convergent plates) or Thrust Fault (low-angle)
· Strike-Slip Fault (horizontal motion; shear forces)
· Be able to distinguish between Left Lateral and Right Lateral
· Transform Fault - connects segments of a spreading ridge where there is plate rotation
· Strike and Dip - orientation measurements used to describe geologic structures.
· Strike - the compass orientation of the line of intersection of a horizontal plane with the structure. 
· Dip - the angle between the horizontal plane and the slope of the structure.
· Strike and Dip Symbol - 1 looks like a capital T and is only drawn on maps.
· Dome
· oldest in the middle 
· looks like an upside down bowl
· Strike is always parallel to the contact lines on the map.
· Basin
· youngest in the middles
· looks like a bowl
· Anticline (anthill)
· oldest in the middle
· Plunging Anticline - plunges toward the nose
· Syncline (smile) - youngest in the middle
· Plunging Syncline - plunges toward the open end
· Overturned Fold

 
GEOLOGICAL HISTORY OF BC - QUICK SUMMARY

At the beginning of the Mesozoic Era, the west coast of Canada in British Columbia was near Salmon Arm. The core of the continent was made of granitic batholiths and volcanics that formed as the Earth cooled 4.5 billion years ago. It was overlain by younger sedimentary rocks (Paleozoic) that formed as the core was weathered, eroded and redeposited in rivers, deserts, and inland seas. A great wedge of sediment accumulated on the west coast of the continent as rivers moved material from the interior to the Pacific Ocean. The entire landmass, which was part of Pangaea, was situated further South; the climate was tropical. There were many swamps filled with vegetation that accumulated as it died and fell to the ground. An inland sea covered Alberta and northeastern BC. The many marine organisms it supported were buried with the sediment deposited by the sea. Dinosaurs inhabited the adjacent land areas. Pangaea broke up about 200 million years ago.

Approximately 170 million years ago several strings of volcanic islands (terranes) collided with the western edge of the North American continent. The collision occurred over many millions of years; the plates were moving only a few centimeters per year . The sedimentary layers that had been piling up along the coast were folded and faulted (thrust faults) by the compressional forces, forming the Rocky Mountains. (Had the crumpling and telescoping not occurred, BC would be 300 km wider.) Erosion wore the Rockies down at the same time and has continued to do so ever since then. (Had erosion not occurred, the mountains would be 10 km higher than they are today.) The volcanic islands that collided with North America have been deeply eroded over time. Isostatic uplift has brought their deeply-formed, batholithic roots to the Earth' surface. The Coast Mountains north of Vancouver, which extend along the coast to Alaska, are the roots of such islands.

More recent volcanics have cross-cut the Coast Mountains forming, for example, Mt Garibaldi near Squamish (Pleistocene) and Mt Edziza north of Terrace (Recent).
A hot spot has formed the Anahim chain of volcanoes southeast of the Queen Charlotte Islands. The North American plate has been moving northwestward over the stationary hot spot forming a linear belt of volcanoes with the oldest at the west end and youngest furthest east.

The Juan de Fuca plate is being subducted under the North American plate. Composite volcanoes in the Cascade Mountains, like Mount St Helen's, Mount Rainier and Mount Baker, have formed above this boundary. Motion along this plate boundary also threatens a big, 9.5 magnitude earthquake expected in this area.


Rock Types
British Columbia has all three rock types:
· Igneous - where there were/are volcanoes, roots of volcanoes, cross-cutting dikes or sills
· Sedimentary - in the Rocky Mountains and local areas across BC from erosion of uplifted areas during mountain building. (Sedimentary rocks make up 3/4 of the continent's exposed rock.)
· Metamorphic - in collision zones (from 170 million years ago or the current subduction zone) where significant T, P and water content changes alter rocks.

Resources
The sedimentary layers in the Rockies contain coal that formed from vegetation falling into the swamps before the collision. Northeastern BC and Alberta have oil and gas derived from the marine organisms that lived and died in the inland sea. Metallic minerals, such as copper sulphides, are formed by magmatic processes and, consequently, are found near the Coast Mountains (roots of ancient volcanoes), the Anahim chain (hot spot volcanoes), and the Cascade Mountains (subduction volcanoes).

Summary
British Columbia formed by elongated segments of mini-continents (terranes) that drifted across the Pacific and docked onto ancient North America. These collisions pushed up the Rocky Mts. Erosion by glaciers, streams, mass wasting, and wind has formed the landscape seen today.

These Quick Summaries were developed for MREPBC teacher workshops.
For more information see  http://www.bcminerals.ca/files/workshop_info/000038.php