Geology 201 – Assignment 2

This assignment includes a number of short-answer questions plus one essay and two lab exercises.

Part A – questions (45 points in total)

(Please answer each of these in a few words.  Point-form is OK.)

1) Summarize the properties and geological origins of the following types of conglomerate: oligomict ortho-conglomerate, petromict ortho-conglomerate, tillite (3 points)

 2) Plot the following sandstone mineral compositions onto the triangular diagram, and name the two types of sandstone.   (4 points) 

 

Framework grains

%

#

%Q

%F

%RF

matrix

A1

80

20

0

3

A2

85

10

5

6

A3

80

15

5

2

A4

85

15

0

3

A5

75

25

0

4

A6

75

20

5

2

A7

80

15

5

3

 

 

 

 

 

B1

65

10

25

16

B2

60

15

25

17

B3

60

10

30

21

B4

65

5

30

14

B5

55

15

30

15

B6

55

10

35

22

B7

50

20

30

12

B8

50

10

40

18

3) Most of the sandstones of the Proterozoic-aged Athabasca Group in northern Saskatchewan are quartz arenites, with well-sorted and well-rounded grains.  What does this tell us about the geological history of these rocks? (2 points)  

4) Describe some of the features of a clay mineral. (1 point)

5) On the world map below outline and/or shade in the areas where deep-ocean sediments are dominated by kaolinite (>20%), montmorillonite (>50%) and illite (>40%). (3 points)

6) List the three main types of cements found in sandstone, and comment on what the presence of each tells us about the conditions during diagenesis. (3 points)

7) Find an example of a braided river from the internet, and explain why this type of river exists where it does. (2 points) 

8) In what part of a meandering fluvial system would you expect to see cross-bedding? (1 point)

9) Examine the following satellite image of the Fraser River delta.  Decide whether this delta is river-dominated, tide-dominated or wave-dominated (or some combination of these), and explain your answer.  (3 points) 

10) Explain why siliceous oozes rather than calcareous oozes are typically found on the deep ocean floor.  (2 points)

11) Give two reasons why carbonate-rich sediments (and eventually limestones) do not form in areas where there is a significant input of terrigenous sediment.  (2 points)

12) How, and in what marine environment, does an oolitic limestone form? (2 points)

13) What is the difference between a micrite and a sparite? (1 point)

14) Explain the origins of the interbeds of chert and iron formation in some banded iron formations (3 points)

15) Explain why the Mediterranean dried up during the Miocene, and describe the geological results of that event. (3 points)

 

Part B - Essay 

Examine the stratigraphic section of the upper six formations of the Nanaimo Gp. on Hornby and Denman Islands, and categorize the six formations according to how they could fit into the Facies A to F for submarine fans described by Mutti and Ricci Lucchi  See pages 193-196 (208 to 212) of the text. 

Either point-form or table-form are acceptable. (20 points)  

For more background information on the geology of Denman and Hornby Islands see this useful map:

http://www.em.gov.bc.ca/DL/GSBPubs/GSMaps/2001-3/GM2001-3_Katnik.pdf

or the paper by Katnick and Mustard at: http://pubs.nrc-cnrc.gc.ca/cgi-bin/rp/rp2_tocs_e?cjes_cjes3-03_40

Part C - Labs

1) Lab 7  Read the lab and complete all of the assignment questions except numbers 9 to 12. (10 points)

2) Answer the questions regarding the Mt. Mark Fm. rocks exposed at Horne Lake (10 points)