Lecture 2 Flashcards

1
Q

What is physiography?

A

Practice that describes the land and topographic features of an area. the controls of terrain and stream channels

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2
Q

Why is physiography important to BC and restoration?

A

BC has a wide range of physiographic features. the physiographic setting of an area allows for the discussion of its geophysical system functioning

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3
Q

WHat is topography dependant on?

A

Geology and Climate. plate tectonics and glaciation largely determine the landscape features and its rock types and surficial soils.
Climate drives the hydrological cycle and influences weathering and earosion of rocks and sediment transfer

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4
Q

What are the 4 major physiographic divisions of BC?

A

Mountain ranges
Plateaux
lowlands
highlands

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5
Q

What are important consequences of tectonic activity?

A
  1. Development of major physiographic zones
  2. The exposure of different rock types at earths surface, each with:
    different limnologies
    susceptibility to weathering
    Resistance to erosion
    structural properties
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6
Q

What are the 4 major types of materials at earths surface?

A

Rock, Sediment, organic Matter, water

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7
Q

describe a rock:

A

A solid, cohesive aggregate of grains composed of one or more minerals

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8
Q

Decribe sediment

A

Generally unconsolidated inorganic materials derived from weathering/erosion of rocks. deposited after transport by water, ice, air, or gravity

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9
Q

Define organic matter

A

Deposits of mainly dead and decaying matter from organisms. this material includes upper horizons of soil, peat, shell beds, organic muds. also includes coal and oil shales.

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10
Q

Describe water

A

70% of earths surface covered by ocean. only 3 percent of all earths water is fresh water.

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11
Q

What are the 3 most abundant elements on earth?

A

Oxygen, silicon, and aluminum

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12
Q

What is a mineral?

A

Any naturally occuring, inorganic, solid substance possessing a definite chemical composition and characteristic atomic structure.

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13
Q

what are most common mineral rocks composed of?

A

silicates, composed of silicon and oxygen… 2 most abundant elements

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14
Q

What are felsic minerals?

A

Composed of felspars and silicate. usually light in color. (quartz)

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15
Q

What are Mafic Minerals?

A

common igneous rocks, usually dark green or black. (Basalt)

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16
Q

What is an Igneous rock?

A

Rock formed by crystallization of molten material

17
Q

What is sedimentary rock?

A

Deposition and cementation of eroded rock/mineral particles

18
Q

What are metamorphic rocks?

A

Physical or chemical change of existing rock by application of heat/pressure, ususally due to tectonic movements of earths crust

19
Q

What kind of characteristics can you use to identify rock types?

A

Hardness, Cleavage (direction of fracture), Composition, colour, luster (Sheen)

20
Q

What is an intrusive rock? (plutonic)

A

Magma cools slowly below the surface- large crystals grow.

21
Q

What is an extrusive rock? (volcanic)

A

Magma cools rapidly above the surface- forms small crystals

22
Q

What is a batholith?

A

Large body of igneous intrusions

23
Q

What is a clastic sedimentary rock?

A

inorganic rock and mineral fragments. can be stratification (layering) or Sorting (how uniform the particle sizes are in the rock) (sandstone, mudstone, shale)

24
Q

What is Precipitate sedimentary rock?

A

Chemical precipitation of inorganic compounds from solution or as hard parts of organisms (shells)(limestones, dolomite)

25
Q

What are Fossils and Organic Sedimentary rock

A

Fossils are preservations of hard parts of organisms sandwiched between layers of sediment. Organics are fragments of tissues of organisms the for peat moss, and can harden into coal

26
Q

What are some examples of metamorphic rocks?

A

Slate, schist, marble, quartzite, Gneiss
limestone under heat and pressure can turn into marble
Sandstone to quartzite

27
Q

How do sedimentary rocks form?

A

When rock fragments (clasts) are deposited or chemically precipitated into large water bodies. often deposited into horizontal layers and beds. tectonic activity then distorts the horizontal beds producing faults and jointing planes.

28
Q

What are some Glacial Depositional features?

A

Outwash features in mountain valleys, terraces and glacial damned lake deposits, terminal moraines.
Plateaus have abundant ablation moraines, eskers and kettles.

29
Q

What are moraines?

A

Commonly reffered to as tills. primary deposits left by glaciations. Basal tills are deposited under, and in contact with, the ice (non-sorted, not bedded, massive) dense, consolidated, cohesive.
Ablation till is material origionally picked up and moved by the glacier. coarser textured, less cohesive, higher porosity, higher bearing strength

30
Q

What are outwash deposits?

A

Found along plains, terraces, deltas and alluvial fans.
Their material propoerties make them highly erodible, leading to slope stability problems. (landslides and gullies) typically composed of fine textured silts and clays, low permeability with low bearing strength.