GG211 Sedimentology
School of Environment & Technology
Semester 1 Examinations January/February 2013
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
Outline the Folk and Dunham classifications of carbonate rocks, and their
advantages and limitations
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
Question 2
Describe the typical sequences of minerals formed when a body of saline water
Discuss, using examples, the major environments where evaporites have formed in
the recent and in the geological past.
Question 3
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.
Discuss the expected changes in the turbidite sequences produced as you move
away from the continental slope, from proximal to distal environments.
Question 4
What is diagenesis? (20%)
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.
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.
Question 6
Outline the typical sedimentary facies produced by delta systems.
Discuss why deltaic facies are of potential importance in economic geology.
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