GG211 Sedimentology
School of Environment & Technology
Semester 1 Examinations January/February 2013
GG211
SEDIMENTOLOGY
Instructions to Candidates:
Time allowed: ONE and a HALF hours
Answer any TWO questions
All questions carry equal marks
21st January–1st February 2013
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GG211 Sedimentology
Question 1
(a)
Outline the Folk and Dunham classifications of carbonate rocks, and their
advantages and limitations
(50%)
(b)
Thin sections of carbonate rocks may show large rhombic crystals of dolomite, which
cut across the primary rock texture. Describe how these dolomite rhombs might have
formed?
(50%)
Question 2
(a)
Describe the typical sequences of minerals formed when a body of saline water
evaporates.
(40%)
(b)
Discuss, using examples, the major environments where evaporites have formed in
the recent and in the geological past.
(60%)
Question 3
(a)
Describe the typical sequence of sediments and sedimentary structures found in an
idealised turbidite unit, and discuss how this sequence relates to the changing flow
regime within a turbidity current.
(60%)
(b)
Discuss the expected changes in the turbidite sequences produced as you move
away from the continental slope, from proximal to distal environments.
(40%)
Question 4
(a)
What is diagenesis? (20%)
(b)
Describe the typical textural and chemical changes that may occur during diagenesis
and lithification of either:
i. a micaceous sandstone, or
ii. a bioclastic limestone.
(80%)
Question 5
Discuss how changes in relative sea level result in the formation of the main stratigraphic
surfaces used for correlation purposes in sequence stratigraphy.
(100%)
Question 6
(a)
Outline the typical sedimentary facies produced by delta systems.
(70%)
(b)
Discuss why deltaic facies are of potential importance in economic geology.
(30%)
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