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Copyright Reserved UNIVERSITY OF PRETORIA

Department of Geology HISTORICAL GEOLOGY - GLY 161

SEMESTER EXAM 12th November 2010

Time: 1½ hours

Internal examiner: Dr A.J. Bumby. External examiner: Prof. P.G. Eriksson

SOME QUESTIONS IN THIS EXAM REQUIRE YOU TO WRITE IN THIS

BOOKLET. PLEASE ENSURE THAT YOU HAND IT IN.

Name:_______________________Student No:_________________________

This exam is composed of two sections: A: Short answers (60 marks). B: Essay or

cross-section (40 marks) Spend approximately 50 minutes on section A, 40 minutes on section B

Section A: Short Answers Answer all the questions.

Write your answers to this section in the answer book

1: Write short notes on four of the following topics: (a.) Drakensberg Group (b.) Rooiberg Group (c.) Dwyka Group (d.) Pretoria Group (e.) Table Mountain Group (f.) Waterberg Group

(16 marks)

2: Draw a sketch cross-section through the Bushveld Complex indicating the relative position of the major rock units (including the floor and roof rocks),. Your cross-section should also show what lithologies (rock-types) are characteristic of each section of the Bushveld, and should show where you would expect to find what economic minerals or rock types.

(17 marks) 3. Compile a list of important palaeo-environmental conditions which encouraged the growth of stromalites in the Late Archaean and Proterozoic.

(5 marks)

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4. Examine the following geological map of South Africa, which has had its legend/ stratigraphic column deleted. Complete the following table of stratigraphic, lithologic and structural units from the South African rock record to link the numbers on the map to the appropriate unit. Alongside each unit, give a number from 1 to 11 to indicate the relative age (1 being the oldest).

Unit No.on

map Relative age

Unit No.on map

Relative age

Unit No.on map

Relative age

Natal Group Waterberg Group

Lebowa Granite Suite

Barberton Greenstone Belt

Transvaal Basin

Limpopo Belt

Stormberg Group

Vredefort Dome

Ventersdorp Supergroup

Namaqua-Natal Belt

Cape Fold Belt

(22 marks)

1

2

3

4

5

6

7

8

9 10 11

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Section B: Long answers:

Read the following instructions carefully! Either write a short text on ONE of the following essay topics, or complete a cross-section based on the accompanying geological map. Note that for the essay questions, the correct use of written English is considered important!

EITHER 5. Essay topic 1: Write an illustrated essay which discusses the following statement: “The rocks and fossils preserved in the Karoo Supergroup elegantly illustrate the effect of active tectonics and climate change on sedimentation and life in Gondwana between the Carboniferous and Early Jurassic periods ”.

(40 marks) OR

6. Essay topic 2: Write an essay discussing the following statement: “The principal of Uniformitarianism can be applied universally throughout the South African geological record, illustrating that the present really is the key to the past.”

(40 marks) OR

7. Construct a scaled cross-section from point Y to point Z on the following geologic map. The section should be plotted on the grid provided below. Your completed section should show topography, the geology beneath the surface, and also indicate the geology removed by erosion. Add a stratigraphic column to the side of the cross-section indicating the relative age of each of the rock types, and indicate on the column the timing of important structural events, relative to the ages of the strata.

(40 marks) TOTAL: 100 marks

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Name:______________________________StudentNo:_____________________

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