Download File - Mr. Derrick Baker

Chapter 1
Landform Patterns and Processes
Topography
· the natural and human features of the Earth’s surface. ie. Surface features
· need to understand difference between relief and elevation
Elevation - the height of a particular point of land above sea level
Relief - the change in elevation over a given distance
Hill
· areas of high relief with elevations no higher than 300 - 600 m
· isolated features
Mountain
· areas of high relief with elevations higher than 300 - 600 m
· most occur in long linear chains called ranges (usually along margins of continents)
Plain
· a level tract of land
· frequently found along coastal areas or at lower elevations
· very gentle slope and no local a relief for thirty metres or more
Plateau
· an extensive, relatively flat upland area
· have been raised upward into higher elevations by movements of the Earth’s crust
· often found in interiors of continents
· because they are often deeply eroded by stream valleys, they have more rugged appearances
than plains
Draw conclusions about patterns in major landforms on the earth’s surface.
· figures on page 8 & 9 of text
· reproducible worksheets 1.3 & 1.4
The Structure of the Earth
· fill in details from page 5 of text on reproducible worksheet 1.1
Core
· Inner Core
· deepest part of the earth (1512 miles deep)
· solid that contains both iron and nickel
· is a magnet, a compass
· Outer Core
· (1419 miles deep)
· similar to the inner core but it is a liquid (contains sulphur and oxygen which lowers the
melting point)
· Mantle
· Occupying 1789 miles
· magma (iron and magnesium) that makes up the mantle
· mostly solid except the outer 200-300 Km which is extremely hot and goopy; very plastic-like
· outermost liquid layer of the mantle is referred to as the asthenosphere
Lithosphere (Crust)
· the crust and that upper layer of the mantle which lies above the asthenosphere
· basically hardened mantle (magma)
· contains two segments, the oceanic and continental crusts
Compressional force
· a force pushing into a part of the earth’s crust, causing it to buckle
· plates move towards one another, squeezing together
· subduction zones sometimes form along these areas
Tensional force
· a stretching force in the earth’s surface which may cause faulting
· plates break apart, moving away from or past each other, which may form a trench as one plate
drops downward
· ridge zones sometimes occur where two plates move apart. Magma may rise between the plates
and form a ridge
See figure 1.9 page 11 and figure 1.10 page 12 - discuss
Discuss formation of volcanoes along ridges, etc. by looking at figures
Mountain Building
Fold mountains
· an upland area formed by the buckling of earth’s crust. Many fold mountains are associated with
destructive or collision margins of plates.
· amount and extent of force and pressure, can create simple or complex forms.
· Anticline
· an arch-like upfold in buckled, bent, or contorted rock.
· looks like the letter ‘A’
· Syncline
· a downfold of rock layers.
· looks like a ‘S’mile
Mountains formed by faulting
· Normal Fault
· a fault in which rocks have moved down the slope of the fault
· two normal faults occur parallel to each other, with plate in-between dropping down as
plates move away from each other - forms rift valley
· land between two parallel faults rises - forms block mountain
· Reverse Fault
· a fault, perhaps caused by a compressional force, where movement is up, rather then
down, the face over which movement occurs.
· Overthrust Fault
· occurs when a plate that undergoes faulting has already experienced folding and its
folded layers are then pushed up and thrust over layers on the faults other side.
Mountains formed by Volcanoes
· Along plate boundaries, heat is generated because of friction, pressure, and decay of radioactive
materials.
· Intense heat melts rock beneath the crust producing magma
· If it reaches surface - through fractures or vents, extrusive volcanic activity takes place.
· Terms
· Lava - liquid rock
· Ash (cinder) - small molten rock fragments
· Vent - Single opening through which the volcanic products erupt
Mild volcanic eruptions
· thin, liquid lava flows
· small amounts of gas
Explosive volcanic eruptions
· thick lava flows
· large quantities of gas, ash and cinders
· why? - thick lava hardens quicker - plugs up - and then must be exploded out
Three types of Volcanic Cones
Ash and Cinder Cone
· eruptions consist mainly of ash and cinders
· thick, slow flowing, rapidly solidifying lava
· shape is symmetrical
· steep sides
· large crater
Shield Cone
· usually milder eruption
· little or no ash and cinders
· very thin, liquid lavas
· broad, flat cones
Composite Cone
· undergoes periods of both explosive and quiet activity
· layers of ash and cinders intermixed with layers of lava
· weak spots may develop on sides with smaller lava flows forming smaller craters
Reproducibly Worksheet 1.6 - Enlarge map part to full page
Mark subduction zones and mid-oceanic ridges
Page 16 question 16a and page 17 question 17a