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Unit notes and practice questions

Grade 9 Geography unit 1: Geological history and topography of Ethiopia

Everything here is for unit 1 of the Grade 9 Geography textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.

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Cards
10
Practice questions on unit 1
2–36
The textbook pages for unit 1

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The Temari lesson on unit 1

A short video lesson on this chapter, made by Temari. It loads only when you press play.

Ethiopia's four geological eras · 3 min · 2 past exam questions worked through

Parts of the lesson

Tap a part to play the lesson from there.

What unit 1 covers

  1. 1.Geography: meaning, scope and branches
  2. 2.Location, size and shape of Ethiopia
  3. 3.Geological history of Ethiopia
  4. 4.Geography: meaning, scope and branch
  5. 5.Location, size, and shape of Ethiopia

Short notes for unit 1

The cards filed under this chapter on the Grade 9 Geography page. Open one at a time.

EraTime SpanMajor Geological Events in Ethiopia
Precambrian4.5 billion to 600 million years agoOrogenesis, intense volcanism, folding, formation of the oldest basement complex rocks.
Paleozoic600 to 250 million years agoMassive denudation and peneplanation, inselberg formation, no rock formation (gap in rock records).
Mesozoic250 to 70 million years agoAlternate sinking and uplifting of landmass, marine transgression and regression, sedimentary rock formation.
Cenozoic70 million years ago to presentUplifting, Trappean basalt lava pouring, Rift Valley faulting, Quaternary volcanism.

When you use it

Use this card to identify the chronological sequence of geological eras and the distinct physical events that took place in the Horn of Africa during each era.

Watch out

The Paleozoic era is the only era that left a gap in rock formation in Ethiopia because denudation dominated and no deposition occurred.

Drafted from Grade 9 Geography, pages 2-36, then checked twice before it went up

Physiographic RegionMajor Highland SubdivisionsMajor Lowland Subdivisions
Western Highlands and LowlandsTigray Plateau, North Central Massif, Shewa Plateau, Southwestern HighlandsTekezze and Angereb, Abbay Dinder, Baro-Akobo, Omo-Gibe Lowlands
Southeastern Highlands and LowlandsHararghe Plateau, Arsi Plateau, Bale Massif, Sidama HighlandsOgaden, Elkerie, Borena, Genale Plains
The Rift ValleyAfar Horst, Fentalle VolcanoAfar Depression, Kobar Sink (Dallol), Chew Bahir, Rift Valley Lakes Basin

When you use it

Use this card to classify Ethiopian relief features into the three primary physiographic regions, along with their respective highlands and lowlands.

Watch out

The Western Highlands account for 44 percent of the country's total land area and are divided into four distinct plateau groups separated by the Rift Valley from the Southeastern Highlands.

Drafted from Grade 9 Geography, pages 2-36, then checked twice before it went up

Practice questions on unit 1

10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.

Question 1

Which ancient Greek scholar coined the term Geography and defined it as the description of the earth?

  1. A.Alexander von Humboldt
  2. B.Eratosthenes
  3. C.Richard Hartshorne
  4. D.Maurice Yeates
Show the answer and why

Answer: B Eratosthenes

Why

Eratosthenes was a Greek philosopher (276-194 B.C.) who combined the words Geo (earth) and Graphos (writing) to coin the term Geography.

Question 2

With which neighboring country does Ethiopia share its longest international borderline?

  1. A.Sudan
  2. B.Eritrea
  3. C.Somalia
  4. D.Kenya
Show the answer and why

Answer: C Somalia

Why

Ethiopia shares a boundary length of 1,600 km with Somalia, making it the longest shared border among all neighboring countries.

Question 3

In which geological era were the ancient crystalline basement complex rocks of Ethiopia formed?

  1. A.The Precambrian Era
  2. B.The Paleozoic Era
  3. C.The Mesozoic Era
  4. D.The Cenozoic Era
Show the answer and why

Answer: A The Precambrian Era

Why

The basement complex rocks are the oldest rocks in Ethiopia and were formed during the Precambrian Era, which lasted from 4.5 billion to 600 million years ago.

Question 4

What is the highest mountain peak in Ethiopia?

  1. A.Mount Tulu Dimtu
  2. B.Mount Ras Dashen
  3. C.Mount Gughe
  4. D.Mount Chillallo
Show the answer and why

Answer: B Mount Ras Dashen

Why

Mount Ras Dashen in the Semein mountain system is the highest peak in Ethiopia, standing at an elevation of 4,620 meters above sea level.

Question 5

Which specialized sub-branch of physical geography studies the patterns of vegetation growth in relation to climate, soil, and human activities?

  1. A.Zoogeography
  2. B.Geomorphology
  3. C.Phytogeography
  4. D.Climatology
Show the answer and why

Answer: C Phytogeography

Why

Phytogeography is the branch of biogeography that focuses on the distribution and growth patterns of plants and vegetation.

Question 6

During the Triassic Period of the Mesozoic Era, the transgression of the sea into Ethiopia resulted in the deposition of which sedimentary rock?

  1. A.Hintalo limestone
  2. B.Upper Sandstone
  3. C.Adigrat sandstone
  4. D.Trappean basalt
Show the answer and why

Answer: C Adigrat sandstone

Why

The Adigrat sandstone was the earliest sedimentary rock formed during the Mesozoic Era when the sea began to transgress into southeastern Ethiopia during the Triassic Period.

Question 7

Based on Ethiopia's total area (1,106,000 km2) and its boundary length (5,260 km), what is the calculated Area to Boundary (A/B) ratio?

  1. A.1.411
  2. B.210
  3. C.593.5
  4. D.3727
Show the answer and why

Answer: B 210

Why

Dividing the total area (1,106,000 km2) by the borderline length (5,260 km) gives 210, meaning 1 km of border safeguards about 210 km2 of hinterland.

Question 8

Which prominent peak is the highest point in the Southwestern Highlands of Ethiopia?

  1. A.Mount Gughe
  2. B.Mount Abbuye Meda
  3. C.Mount Tsibet
  4. D.Mount Guna
Show the answer and why

Answer: A Mount Gughe

Why

Mount Gughe, located in the Gamo plateau, rises to 4,200 meters above sea level and is the highest elevation in the Southwestern Highlands.

Question 9

Why is the Paleozoic Era unique in the geological history of Ethiopia?

  1. A.It was the era when extensive basaltic lava created the high plateaus.
  2. B.It left a gap in rock formation because intense denudation and peneplanation prevailed.
  3. C.It was marked by rapid marine transgression from the Indian Ocean.
  4. D.It produced the major rift valley faults across the Horn of Africa.
Show the answer and why

Answer: B It left a gap in rock formation because intense denudation and peneplanation prevailed.

Why

During the Paleozoic Era, the dominant processes in Ethiopia were denudation and peneplanation without any major structural formation, leaving a complete gap in rock formation.

Question 10

What does Ethiopia's Boundary-Circumference (B/C) ratio value of 1.411 indicate about the country's shape?

  1. A.The country has a completely elongated and linear shape.
  2. B.The shape deviates by 41% from an assumed theoretical circular shape.
  3. C.The country has an area 1.411 times larger than the African average.
  4. D.The territory forms a perfectly compact circle.
Show the answer and why

Answer: B The shape deviates by 41% from an assumed theoretical circular shape.

Why

A B/C ratio of 1.411 represents a 0.411 (or 41%) deviation from the ideal value of 1.0, showing that Ethiopia is approximately compact with a 41% divergence from a perfect circle.

The app holds 12 questions on this unit, marked as you go. These are the first 10.

The textbook pages for unit 1

Unit 1 runs from page 2 to page 36 of the Ministry of Education edition.

Ministry of Education edition, English, 247 pages

Download the PDF

All Grade 9 Geography short notes

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