CanadaCanadaUNIT 2: Physical diversityUNIT 2: Physical diversity

Chapter 4:Chapter 4: Geologic HistoryGeologic History

Geological HistoryGeological History• Our physical appearance has changed over time.• Land is being built up. HOW?• Volcanoes• Moving plates• Deposition• Land being worn away. HOW? (Erosion)• Rain, rivers and oceans• Wind• GlaciersEx. Ancient seas have disappeared.

Mountains that were once high are now worn flat.Pages 26-27

Geologic HistoryGeologic History

• Many years ago Canada’s landscape looked very different from how it looks today.

• Two forces have mainly changed the physical landscape.– Erosion and Mountain building.

• One being stronger than the other….

Q. How have things changed over time?

Geologic HistoryGeologic History

Geologic time: history of how the earth has changed from its formation to the present.

• Earth is approx. 4.6 billion years old.

• Earth’s geologic history can be divided into 4 eras (time periods).– Cenozoic– Mesozoic– Paleozoic– Precambrian

Geologic HistoryGeologic History

• Each era represents a time of major sediment deposition and earth movement.

• In other words, significant building up, wearing down and movement of the land.

Precambrian Era

– Refers to “earliest life” and is the oldest!!!– 4.6 billion to 600 million years ago.– Lasted over 4 billion years.– Many cycles of building and wearing down

(EROSION).– Our continent and in particular, the Canadian

Shield was formed during this era.– Primitive life forms such as single-celled

plants and animals.– Pages 28 - 29

The Canadian Shield

Paleozoic Era

• refers to “ancient life”

• 600 to 225 million years ago (lasted 375 million years).

• More mountain building, but lots of erosion of the Canadian Shield as well.

• Erosion produced sediments which are small particle of rock that have been worn down.

• These sediments were moved about by rivers and deposited elsewhere.

Paleozoic Era

• Layers of sediments were compressed together to form sedimentary rock.

• They have become the bedrock (underlying solid rock beneath the layer of soil) in every province.

• Appalachian mountains in Eastern Canada formed (p. 30) when these layers of sedimentary rock were forced UPWARDS.↑

The Appalachians

Formation of the AppalachiansFormation of the Appalachians

MesozoicMesozoic

• Refers to the “Middle life.”

• 225 to 70 million years ago

• Innuitian mountains formed when eastern Arctic “FOLDED”

• Rocky Mountains in Western Canada started to form (at the end).

Mesozoic – Formation of fuel deposits(page 31-top)

• Warm climate• =

• swamps and forests• =

• Dead trees & Vegetation• =

• Swamps, sand & silt• =

• Compressed layers• =

• Coal, oil and gas deposits formed

Cenozoic• Refers to “recent life.”

• 70 million years ago to now (has not ended).

• More mountain building through folding, volcanoes and faulting.

• Glaciers were the most significant force in shaping the land during this era and especially Canada as we know it today!!

• They eroded and rounded the Canadian Shield and Appalachian Mountains.

Cenozoic• Once melted, they deposited the eroded

material to create the lowlands surrounding the Canadian Shield.

• Some are still present today in Canada.

• Age of mammals (including humans!)

• Great Lakes - St. Lawrence Lowlands

• Hudson Bay - Arctic Lowlands

• Interior Plains

Questions - ReviewQuestions - Review

Page 32• #1 = ( 1 Pt)• #2a = (2 Pts)• #2b = ( 3 Pts)• #3a = ( 1 Pt)• #4a = ( 1 Pt)• #4b = ( 1 Pt)• #4c = ( 1 Pt)• #4d = ( 1 Pt)

• Page 32 • #5b = ( 1 Pt) • #6a = ( 1 Pt)• #6b = ( 1 Pt)• #7a = ( 1 Pt)• #7b = ( 1 Pt)• #7c = ( 1 Pt)• #7d = ( 1 Pt)