Cameroon GCE advanced level June 2026 geology 1

Question 1

Which of the following explains the origin of the Solar System?

• A Universal theory

• B Nebular theory

• C Big Bang theory

• D Planetesimal theory

Question 2

What is the main cause of the Big Bang?

• A High pressure within the system

• B High temperature within the system

• C Presence of electrons within the system

• D The clustering of stars within the system

Examine the sketch below (figure 1) which shows the upper 670km of the Earth and answer questions 3 and 4.

[Insert Image Placeholder: Figure 1 – Upper 670km of the Earth Layer Diagram]

Question 3

Identify the discontinuity that exists at depth of 35km.

• A Gutenberg Discontinuity

• B Conrad Discontinuity

• C Lehman Discontinuity

• D Mohorovicic Discontinuity

Question 4

What is the physical state of the layer labelled Y?

• A Solid

• B Plastic

• C Molten

• D Elastic

Figure 2 below illustrates schematically Time – Distance plots for three different types of earthquake waves, labelled X, Y and Z. Use the curves and answer questions 5 and 6.

[Insert Image Placeholder: Figure 2 – Time-Distance Graph for Earthquake Waves]

Question 5

Determine the velocity of the wave labelled Y at 25km from point 0.

• A 375 km/s

• B 55km/s

• C 1.6km/s

• D 750km/s

Question 6

The curve represented by the letter Z corresponds to:

• A S-waves

• B P-waves

• C L-waves

• D Rayleigh – waves

Question 7

A crystal face in the Tetragonal system has as Miller Index ($111$). To what form does this face belong?

• A Bipyramid of the second order

• B Pinacoid

• C Bipyramid of the first order

• D Tetrahedron

Carefully study the crystal drawing below (figure 3) and answer questions 8 and 9.

[Insert Image Placeholder: Figure 3 – Crystal Drawing with axes X, Y, Z]

Question 8

What is the diagnostic characteristic of this crystal?

• A Four three – fold axes of symmetry

• B One vertical three – fold axis of symmetry

• C Three two – fold axes of symmetry

• D One four – fold vertical axis of symmetry

Question 9

Which form is represented by the crystal above?

• A Cube

• B Rhombdodecahedron

• C Scalenohedron

• D Rhombohedron

Question 10

Which of the following properties is diagnostic of the Mica group of minerals?

• A Basal cleavage

• B Colourless streak

• C Vitreous lustre

• D Low specific gravity

The diagram below (figure 4) shows a section of a silicate mineral cut at right angles to the length of the crystal. Use this diagram to answer questions 11 and 12.

[Insert Image Placeholder: Figure 4 – Silicate Mineral Cleavage Planes Section]

Question 11

The cleavage planes drawn above are typical of:

• A Olivine

• B Biotite

• C Hornblende

• D Pyroxene

Question 12

The mineral in question 11 has a:

• A Sheet structure

• B Double chain structure

• C Framework structure

• D Single chain structure

The diagram below (figure 5) shows a sequence of rocks in an area formed during volcanic activity. The upper part of each basalt contains vesicles. Study it and answer questions 13 and 14.

[Insert Image Placeholder: Figure 5 – Volcanic Rock Stratigraphy Sequence]

Question 13

How many violent volcanic activities have taken place in the area?

• A Three

• B Two

• C Five

• D Six

Question 14

The vesicles in basalts 1, 2 and 3 were most likely formed as a result of:

• A Fast cooling of lava

• B Gases trapped in the lava

• C Fluids trapped in lava

• D Escape of volatiles from the lava

An igneous rock X was analyzed as having the following chemical composition. Study the information given below and answer questions 15, 16 and 17.

• $\text{SiO}_2 = 50\%$

• $\text{Fe}_2\text{O}_3 = 3.2\%$

• $\text{CaO} = 11.7\%$

• $\text{FeO} = 6.0\%$

• $\text{Others} = 29.1\%$

Question 15

If this rock is phaneritic, identify the rock:

• A Granite

• B Diorite

• C Gabbro

• D Peridotite