GCE A - LEVEL GEOLOGY PAPER 2 JUNE 2019

 SECTION A

1. a) Explain five ways by which fossils have been used to determine ancient climate.
   b) Write a brief geologic history of the bivalves.
   c) Draw an anisomyrian bivalves shell and label the following parts: muscle scar, dentition, ligament.
2. a) Outline the nature of hard parts of organisms that make them suitable for fossilization.
   b) Discuss the effects of transportation, diagenesis and post depositional changes on fossilization.
3. a) What do you understand by an unconformity?
   b) How can you recognise the following unconformities on geological maps?
   i) Angular unconformity
   ii) Heterolithic unconformity.
   c) state the characteristics of :
   i) Parallel unconformities;
   ii) Non-depositional unconformities
   d) Outline the importance of unconformities.

SECTION B

1. a) Define the term magmatic differentiation.
   b) Describe the following processes of magmatic differentiation:
   i) Crystal settling;
   ii) Mechanical filter pressing.
   c) Describe the following processes in the formation of igneous rocks:
   i) Assimilation;
   ii) Hybridization;
   iii) Liquid immiscibility.
2. a) Name the three main types of rocks.
   b) Explain how each of the rocks mentioned in a) above were formed.
   c) Outline the importance of rocks to a geologist?

SECTION C

1. a) What do you understand by maturity of a sediment?
   b) Explain the compositional and textual maturity of a sediment.
   c) Relate the maturity of a sediment to the various stages of a river.
2. a) Discuss the various features associated with sea level changes and the nature of the evidence.
   b) Briefly differentiate between:
   i) Bars and spits;
   ii) Tombolo and cuspate foreland.
3. a)What do you understand by exogenetic mineral deposits?
   b) With examples, outline the different types of exogenetic mineral deposit.
   

SECTION D

1. a) Describe five different topographic features found on the ocean floor.
   b) Define the sea floor spreading hypothesis and explain three evidences that have been proposed to prove its existence.
2. a) Explain how the following can trigger mass movement of rocks and soil:
   i) Angle of slope;
   ii) Rock type;
   iii) Groundwater or rainfall;
   iv) Ground vibration.
   b) Outline the attempt that are made to manage and control unstable slopes.
3. a) Explain the classification of crystals into systems and classes.
   b) Outline the symmetry elements of the following:
   i) Galena;
   ii) Calcite;
   iii) Barytes.
   c) Define the following forms as used in crystallography
   i) Octahedron;
   ii) Pyramid;
   iii) Dome;
   iv) Pinacoid.