982001 SASTA GEOLOGY REVISION GUIDE
PRACTICAL SECTION
Note
The questions in this section require the use of actual mineral and rock specimens. The specimens required for each question are listed just before the answers to that question. A knife, quartz crystal, copper coin, streak plate, magnet, hand lens, and acid should be used where appropriate.
Use specimens 1A to 1E, which are listed at the beginning of the answers to Question 1.
1. (a) Describe the cleavage, if present, of minerals 1A and 1B.
(b) What physical property, other than cleavage, obviously distinguishes minerals 1A and 1B? (c) (i) To which of the categories igneous, sedimentary, or metamorphic do rock specimens 1C
and 1D belong?
(ii) Give reasons for each of your classifications.
(d) Describe the textures of the rock specimens 1C and 1E. (e) Briefly account for the possible development of the textures of rocks, 1C and 1E.
Use specimens 2A to 2F, which are listed at the beginning of the answers to Question 2.
2. (a) Determine the hardness on Moh’s
scale of minerals 2A and 2B.
(b) Specimen 2C is the dominant
rock type in the shaded area shown on the adjacent map. Specimen 2D is a mineral. Grains of this mineral are concentrated
on the beach in the dotted area only, as shown on the map.
(i) Suggest the origin of
specimen 2C, and give reasons for your answer.
(ii) What physical properties
of specimen 2D have been responsible for its concentration in the area shown on the map? Explain your answer.
Study specimen 2E and the adjacent map when answering Questions (c) and (d).
Area i - granite
Area ii - intensely folded high grade metamorphic
rocks - mainly metamorphosed sandstone
Area iii - intensely folded low grade metamorphic
rocks - mainly metamorphosed shales
Area iv - intensely folded unmetamorphosed
sedimentary rocks
(c) To which area on the map does specimen 2E most likely belong? Give reasons for your choice. (d) Indicate, with reasons, the suitability of specimen 2E
(i) for use as a roofing material(ii) for use as a road material.
Study specimen 2F and the adjacent map when answering Questions (e) and (f).
Area i - lava flows
Area ii - pluton
Area iii - metamorphic aureole
Area iv - sedimentary rocks (e) To which map area does specimen 2F most likely
belong? Give reasons for your choice.
(f) Indicate, with reasons, the suitability of specimen 2F as
(i) an aquifer. (ii) a dam foundation.
Use specimens 3A to 3D, which are listed at the beginning of the answers to Question 3.
3. All of the following questions refer to the geological map and section across X-Y, which are on
the following page. (a) Describe rock specimen 3A.
Describe the probable environment of deposition for specimen 3A.
(b) Describe rock specimen 3B. (c) Specimen 3C was found to occur in the position indicated on the map. Describe three physical
properties of this mineral.
(d) How might specimen 3C have formed? (e) Describe rock specimen 3D in terms of its texture and mineralogy. (f) Suggest how specimen 3D and its associated landform (shown on the cross-section) might
have formed.
(g) Assuming the fault movement to have been vertical, is the north side of the fault upthrown or
downthrown? What evidence did you use to reach this decision?
(h) Briefly list in order the sequence of geological events shown on the map and section.
Make sure you state which events are the oldest and which are the youngest.
Use specimens 4A to 4C, which are listed at the beginning of the answers to Question 4 .
4. All of the following questions refer to the figure on page 101, which is a sketch map of the
aerial photograph (Landsat image) on p. 316 of Perspectives of the Earth. (a) Describe rock specimen 4A (found in region I).
Discuss how this rock may have formed.
(b) Describe rock specimen 4B (found in region II close to the boundary with region I). (c) Describe rock specimen 4C (found in region II).
This rock consistently breaks into pencil-like (elongate prism) shapes. Suggest a reason for this.
(d) Describe the main topographic and geologic features of Pre-Cambrian region II shown on the
Landsat image.
Suggest two ways in which region I appears to be different from region II.
(e) From region II describe the relationship between the Cambrian and Proterozoic rocks.
Name one geological structure containing the Cambrian rocks.
(f) Describe the main topographic and geologic features of the Cainozoic region III and suggest
how they might have formed.
(g) What type of geological boundary is there between the two regions (II and III) on the west
side of region II? Suggest a reason why this boundary appears different on the other (east) side of region II.
(h) Describe the most prominent topographic feature of region IV.
How might it have formed?
(i) Explain why regions III and IV are different. (j) Sedimentary features marked X are shown at the southern end of region V. Suggest how they
were formed.
Refer to this map when answering Question 3.
Refer to this map when answering Question 4.
Age / RegionProterozoic / I - specimens 4A and 4B
II - specimen 4C
(region II includes minor
Cambrian)
Cainozoic / III
IV
V
Use specimen 5A which is listed at the beginning of the answers to Question 5.
5. This question refers to the satellite image of part of the Pilbara area of Western Australia which is
on page 431 of ‘Perspectives of the Earth’. (a) The thin dark lines crossing the light-coloured areas are dolerite dykes.
(i) Name two minerals which you would expect to find in dolerite. (ii) Is the dolerite older or younger than the rocks of the light-coloured areas? (iii) Explain your answer to part (ii).
(b) Specimen 5A is plagioclase feldspar, a mineral which is found in some rocks in the light-
coloured areas. (i) Describe three physical properties which would help in its identification. (ii) What is the most likely mode of occurrence of this mineral?
Use specimens 6A to 6D, which are listed at the beginning of the answers to Question 6.
The diagram and cross-section below show a partly completed geological map and a geological cross-section X-X1. Geological data for two other traverses, Y-Y1 and Z-Z1, are shown on the map. The specimens labelled 6A to 6D have been collected from the positions shown on the cross-section.
6. (a) (i) Using the data from the traverses, sketch the continuation of the fault across the map.
(Assume that the fault is continuous across the map.)
(ii) Sketch the positions of the upper and lower boundaries of rock type 6A. (iii) Sketch the positions of the rock boundaries to complete the map on the eastern side of
the fault.
(b) (i) What sort of fold is fold 1?
(ii) In which direction is fold 1 plunging?
(c) (i) Is the fault a normal fault or a reverse fault?
(ii) Explain your answer to (i).
(d) Use the symbol to clearly show the position of an angular unconformity on the map.
(e) This question refers to rock specimen 6A.
(i) Describe the grain size, grain shape, and sorting of the grains in this rock. (ii) Name this rock. (iii) Describe the environment in which this rock probably formed.
(f) This question refers to rock specimen 6B.
(i) What are the two main components of this rock? (ii) Describe the environment in which this rock probably formed.
(g) This question refers to rock specimen 6C.
(i) Describe three physical properties of one of the minerals which
make up this rock.
(ii) Describe the texture of this rock. (iii) What evidence is there to suggest that this is an igneous rock?
(h) This question refers to mineral specimen 6D.
(i) How many sets of cleavage planes are present in this mineral? (ii) Approximately what angles do these cleavages make to each other? (iii) Describe two physical properties, other than cleavage and colour,
which would help to identify this mineral.
(iv) This mineral was found in a vein in the rock unit from which
specimen 6C was collected. How might this mineral have formed?
(i) Using the symbols shown on the map and cross-section, indicate in the
spaces (at right) the order of formation from youngest to oldest of all of the rock types shown on the map and cross-section.
(j) Clearly indicate when the folding occurred by placing a mark and the
label ‘folding’ at the appropriate time in the sequence of rocks you have drawn in part (i).
Use specimens 7A to 7C which are listed at the beginning of the answers to question 7
Question 7 refers to the map, cross-section and key on the following page.
7. (a) (i) Into which of the three broad regions of continental crust (shield, orogenic zone, or basinal
area) does the map area fit?
(ii) Give one geological reason for your answer to part (i).
(b) This question refers to rock specimen 7A.
(i) Describe the grain size, grain shape, and sorting of the grains in this rock. (ii) Name this rock. (iii) From which rock unit on the map could this rock have come? (iv) Describe an environment in which this rock might have formed.
(c) The universal symbol used on maps to indicate fossil locations is . This is not a true
picture of the actual fossils found at the location. (i) What would the fossils found in a road cutting at location 1 most likely be -
archaeocyathids, graptolites, or dinosaur bones?
(ii) Give the geological reasons for your choice in part (i).
(d) Rock specimen 7B comes from the unit labelled ‘nb’ in the Map Reference.
(i) Describe three minerals present in this rock by completing the table below.
(ii) Describe the texture of this rock.
(iii) What does this texture indicate about the mode of formation of this rock? (iv) A student studying this rock suggested that it contains olivine. Give one reason why this
observation is unlikely to be correct.
(v) What are the geological features labelled ‘nb’ on the map?
(e) Rock specimen 7C was collected from location 2 on the map. It is composed mostly of one
mineral.
(i) Describe three properties of the mineral that would help in its identification. (ii) Name this rock. (iii) Given the location from which this specimen was collected, suggest the likely method of
formation of this rock.
(f) How is the unit labelled ‘Czb’ different from the other igneous rocks in the area? (g) A proposal has been made to dam the Murrumbidgee River in the area near location 3.
Describe three factors that a geologist would need to investigate if this location were selected as the site for a dam.
(h) A geologist is employed to explore the map area for potential sites for an aggregate quarry to
supply a concrete plant in Canberra. (i) Why would the geologist be likely to begin the search in the south-east corner of the
map area?
(ii) Name one rock unit in the map area that might be a suitable source of aggregate. (iii) Give one geological reason for your choice in part (ii).
(i) (i) Folded rocks outcrop in the northern central part of the map area. In what direction did
the compressional forces that caused this folding act?
(ii) Between what ages was the latest folding event shown on the map? (iii) Give a geological reason for each of the ages you chose in part (ii).
8.To answer question 8, use the map on the following page, and rock specimens 8A and 8B,
which are named at the beginning of the answers to this question.
(a) Name one igneous rock, one sedimentary rock, and one metamorphic rock present in the area
shown on the map sheet.
(b) From the map and legend, list three indicators that orogenic activity took place during the
Palaeozoic era.
(c) Refer to the adjacent diagram which is an enlargement of Box 1
on the map sheet. Outline the geological history of this region in point form. (The oldest event, the deposition of the Woolshed Flat Shale, is provided.)
• ______
• ______
• ______
• ______
• Deposition of the Woolshed Flat Shale.
(d) (i) What is the general direction of plunge of the major folds in the north-west region of the
map?
(ii) Name a formation on the map that is not tilted.
(e) Refer to the adjacent diagram which is an
enlargement of Box 2 on the map sheet. (i) Explain the formation of the rock type
around Mount Kitchener.
(ii) What name is given to such zones of
altered rock?
(iii) Name two minerals that you would
expect to find as common constituents of the Mount Kitchener granite.
(iv) Name two textural features
characteristic of granite.
(v) Name two processes that followed the
original intrusion and caused Mount Kitchener to become a prominent landform.
(f) (i) Name one use of the rock quarried at Location X.
(ii) Name two properties of this rock that make it suitable for the use you have named in
part (a).
(g) There are a number of quarries in the area shown on the map.
(i) Name one possible use of the resource mined at the quarry at Location W. (ii) Name two economic considerations that would face a mining company intending to
establish a new marble quarry in the area shown on the map.
(h)This question refers to rock specimen 8A.
(i) This specimen has three components: clasts, matrix sediment, and cement. Describe the
following: • Grain size of clasts • Grain shape of clasts
• Grain size of matrix • Degree of sorting
• Type of cement (ii) Name the rock (iii) A geologist decided that the environment of deposition of this rock was one of high
energy. Give one piece of evidence that led to this conclusion.
(i) This question refers to rock specimen 8B.
(i) The field geologist who collected this specimen decided it was metamorphic. Describe
the texture of this rock that led to this decision.
(ii) What force acted on the original rock to produce this texture? (iii) Name the mica mineral present in this rock. (iv) Name the rock unit on the map sheet from which this specimen could most likely be
collected.
(v) Describe one change that could happen to this rock if it undergoes further metamorphism.
108 2001 SASTA GEOLOGY REVISION GUIDE
9. Refer to the map on the following page, together with specimens 9A and 9B which are listed at the
beginning of the answers to question 9. (a) (i) Name the two broad regions of the continental crust that are shown in this map area.
(ii) Give one geological reason for each of your answers in part (i).
(b) A field geologist is measuring the orientation of the rocks outcropping at location Q. He/she
observes that the beds have not been overturned. (i) In which direction would h/she have found the beds dipping? (ii) What is the strike of these beds at location Q?
(c) (i) Name the rock unit on the downthrow side of the fault at location R.
(ii) Give one geological reason for your answer to part (a).
(d) The diagram below is a sketch of the ductile structure outlined in box 2. (i) Accurately mark the axial plane of the structure on the diagram above.
(ii) Mark on the axial plane the direction of plunge.
(e) (i) Name tworock types shown on the map that are indicators of past climates.
(ii) Give onereason for each of your answers in part (i).
(f) Name the type of boundary between the rocks at location S. (g) This question refers to the cross-section of the North Field, Lobe ‘D’, under the map.
(i) Give three geological reasons for choosing the open-cut method, using evidence from the
cross-section.
(ii) State one advantage and one disadvantage of the location of the mining township in
box 1.
(iii) State two environmental problems associated with open-cut extraction, and suggest how
they could be minimised.
(h)This question refers to rock specimen 9A.
(i) Describe the texture of this rock. (ii) Explain the formation of this texture. (iii) Name two major constituent minerals in this rock. (iv) Choose one of the minerals you have named in part (iii) and describe two of its physical
properties. (Indicate which mineral you are describing.)
(v) State one commercial use of this rock. (vi) Name the rock type from the map area that is most closely related to this rock in chemical
composition.
(i)This question refers to rock specimen 9B.
(i) This rock has undergone metamorphic change. Describe two textural features of the
original sedimentary rock (other than colour).
(ii) What type of metamorphic texture does this rock display? (iii) Which mineral is chiefly responsible for this texture? Explain your answer. (iv) What type of metamorphism produced this texture? (v) Why is it more likely that this specimen was collected from the Bunyeroo Formation
(point T on the map) than from the Amberoona Formation ( point U on the map)?
Refer to this map when answering Question 9.
110 2001 SASTA GEOLOGY REVISION GUIDE
Refer to this map when answering Question 10.
Adapted from Dalgarno and Johnson (1966)
Courtesy Mines and Energy Resources South Australia
Specimens 10A to 10C are named at the beginning of the answer to question 10.
Parts (a) to (c) contain references to the map on page 110.
10. (a) (i) Name the crustal element shown in the eastern part of the map.
(ii) Give one geological reason for your answer to part (a) above.