Test #3 WRITTEN RESPONSE QUESTIONS PART B: WRITTEN RESPONSE 2006 Value: 30 marks Suggested Time: 40 minutes TEST #3: Rocks and The Rock Cycle 2007R* 4 2006R* 1, 2 2005R* 1, 12 2004 1, 2, 3 2003 2, 3, 4 2002 1 2001 1, 2, 3 2000 1, 2 1999 3 1998 1, 2 1997 1, 2 1996 1, 8 INSTRUCTIONS: Answer the following questions in the space provided in the Response Booklet. You may not need to use all of the space given. 1. Sediment is being deposited in the centre of a lake in BC at the current rate of 1 mm/year. A drill hole in the centre of the lake reveals that the thickness of sediment is 11 m. (Note: 1 m = 1000 mm). a) How long has the sediment been accumulating in the lake? Show all calculations. 2007 years Refer to the Geological Map on page 13 and Photograph 1 on page 14 of the Data Pages to answer question 4. Data Page 13 Page 14 b) Describe a geological assumption you made in order to perform this calculation. 4. Photograph 1 shows the Precambrian metamorphic rock shown on the geological map. The rock contains quartz, feldspar and biotite mica. Describe the metamorphic rock. In your description include the name of the metamorphic rock, the nature of the parent rock, the physical conditions under which it would have formed, and the type of plate tectonic boundary at which it would have formed. (4 marks) Geology 12 0708 Response Booklet Page 3 Geology 12 0608 Response Booklet Page 1
Use the following photograph of an igneous layer to answer question 2. 2006 PART B: WRITTEN RESPONSE 2005 Value: 45 marks INSTRUCTIONS: Suggested Time: 55 minutes Answer each question in the space provided. You may not need to use all of the space given. X Use the following partial, simplified, rock cycle diagram to answer question 1. Metamorphic Rock PROCESS 3 Magma PROCESS 2 PROCESS 4 GSC Sedimentary Rock Igneous Rock 2. Describe two pieces of evidence that could be found in or near the dark igneous layer at X to establish that it was a sill, and not a buried lava flow. PROCESS 1 Sediment Example Process 5 Evidence 1: 1. Choose any two processes from the diagram above. For each process, describe the process and its probable plate tectonic location. An example is given. (4 marks) Evidence 2: Process # Description of Process Plate Tectonic Location Example: Process 5 Igneous rocks in volcanic mountains are weathered and eroded to become sediments. Volcanic mountain range at converging plates. Page 2 Geology 12 0608 Response Booklet 2005 Province of British Columbia. All rights reserved. Page 25
Use the following diagram of ripple marks and cross-bedding to answer question 2. 2005 2005 Reference Data Pages in the Appendix For question 12, refer to the following references in the Appendix. page 1: Bowen s Reaction Series page 4: Percentage of Minerals in Igneous Rocks page 5: Properties of Common and Important Minerals west east 12. A company makes large ornamental fountains and pools. The company has decided that the two most attractive rocks to use are a polished limestone and a polished granite. The mineral composition of the rocks is given in the table below. 2. Describe how this structure might have formed. Include direction of flow in your answer. Rock Granite Limestone Minerals present mainly quartz, potassium feldspar calcite Describe two mineral characteristics that would make the granite more suitable than the limestone. Characteristic 1: Characteristic 2: Page 26 2005 Province of British Columbia. All rights reserved. 2005 Province of British Columbia. All rights reserved. Page 39
PART B: WRITTEN RESPONSE 2004 Use the following map to answer question 2. 2004 Value: 45 marks INSTRUCTIONS: Suggested Time: 55 minutes Answer each question in the space provided. You may not need to use all of the space given. Kohala Direction of lithospheric plate movement REFERENCE DATA BOOKLET For question 1, refer to the diagram below and the following in the Data Booklet. page 10: Percentage of Minerals in Igneous Rocks Hualalai Mauna Kea Older Younger rocks rocks LEGEND Older rocks Mauna Loa Kilauea Younger rocks High temperature and pressure Formation of light and dark bands Siltstone Compaction and cementation Weathering and erosion to silt Seismic station Zulu 50 km Recent earthquake epicentre magnitudes 4.0 4.4 4.5 5.4 >5.4 Recent volcanic eruptions Site of lava flow Rock X Melting Rock Y Slow cooling inside the earth 2. The map above shows the island of Hawaii, and the locations of several recent volcanic eruptions which are building shield volcanoes. The island is over a hot spot. a) What is the likely composition of the lava from these eruptions? Felsic/silicic magma b) Explain why a pyroclastic flow (nuée ardente) is unlikely in this area. 1. a) What type of rocks are rocks X and Y shown in the diagram above? Rock X: Rock Y: b) Describe a plate tectonic situation that would cause the high-grade metamorphism of the siltstone. c) Place an X on the map in an area where you would expect the volcanic activity to increase over the next several hundred years. - 23 - - 24 -
d) Sketch and describe the likely cross-sectional shape of the shield volcanoes in this area of Hawaii. Sketch Description 2004 Percentage of outcrop Use the following graph to answer question 3. 50 40 30 Tertiary 41 Cretaceous Jurassic Triassic Permian Pennsylvanian Mississippian Devonian Silurian Ordovician 26 Cambrian Precambrian 20 13 10 8 5 3 4 0 0 100 200 300 400 500 600 Age of Rock (millions of years) 2004 REFERENCE DATA BOOKLET For question 2e), refer to the following in the Data Booklet. page 10: Percentage of Minerals in Igneous Rocks page 12: Bowen s Reaction Series 3. The graph shows the relationship between the age of sedimentary rocks compared to the amount of outcrop, or area, they cover on the Earth s surface. Give two reasons why only 20% of the sedimentary rocks visible today are older than 300 million years. e) A sample of coarse-grained rock was collected from a Kilauea lava flow, and geologists think it is an ultramafic xenolith brought up from the mantle. The rock has the following mineral composition. Reason 1: Mineral Percent by volume Reason 2: plagioclase feldspar 5% pyroxene 70% olivine 25% How can geologists tell that the material in the xenolith must have formed at a temperature above 1000 C? - 25 - - 26 -
Value: 45 marks INSTRUCTIONS: REFERENCE DATA BOOKLET PART B: WRITTEN RESPONSE Suggested Time: 55 minutes Answer each question in the space provided. You may not need to use all of the space given. 2003 For question 1, refer to the table below, and the following in the Data Booklet. page x: Bowen s Reaction Series page xii: Properties of Common and Important Minerals REFERENCE DATA BOOKLET For question 2, refer to the following in the Data Booklet. page i: Geological Map 2003 2. A geologist has observed that the crystals in igneous rock unit S are much smaller at points X and Y than they are at a point half way between X and Y. Explain why the crystals are smaller at X and Y than in the middle of the unit. Minerals present Mineral content of granite Mineral content of stream sand potassium feldspar 60% 18% quartz 30% 80% biotite 10% 2% REFERENCE DATA BOOKLET For question 3, refer to the following in the Data Booklet. page i: Geological Map page vi: Photograph 10 1. An area of British Columbia that is entirely composed of granite is drained by a single, fast-moving stream. With reference to chemical and physical properties, describe two factors which could be used to explain why the mineral content of the stream sand has become so different from the mineral content of the granite. Factor 1: 3. Sedimentary structures are very useful to geologists because they can give clues about the environment where the sedimentary rock they occur in was deposited. The sedimentary structure shown in Photograph 10 was found in the sandstone T shown on the geological map. a) Identify the sedimentary structure. b) Describe how the sedimentary structure would have formed. Factor 2: c) Name an environment where the sedimentary structure could have formed. - 24 - - 25 -
Use the following graph which shows relationships between temperature, depth, and types of coal, to answer question 4. Temperature in degrees Celsius 2003 2003 d) Why is anthracite (hard coal) often found in association with slate rather than shale or mudstone? Depth in kilometres 0 1 2 3 4 5 6 25 50 75 100 125 150 175 200 225 Peat 40 60% carbon Lignite coal 60 70% carbon Bituminous coal 70 90% carbon Use the following cross section diagrams of coal deposits to answer question 4e). Note the different scales of the cross sections. X Y 7 8 Anthracite coal (hard coal) 90 95% carbon 9 4. a) Describe a type of environment where a potential coal deposit could accumulate on the earth s surface and the type of material that would accumulate to eventually become coal. Type of environment: coal seam 2 m coal seam 100 m Type of material: e) The two coal deposits X and Y were discovered in British Columbia, however neither of them will be mined at this time. i) Describe any geological or economic reason why deposit X will not be mined. b) According to the graph, at what temperature and depth would lignite change to bituminous coal? Temperature: Depth: c) Choose one type of coal and describe a use for it. ii) Describe a different geological or economic reason why deposit Y will not be mined. - 26 - - 27 -
Value: 45 marks INSTRUCTIONS: PART B: WRITTEN RESPONSE Suggested Time: 55 minutes Answer each question in the space provided. You may not need to use all of the space given. 2002 REFERENCE DATA BOOKLET For questions 1b) to 1d), refer to the following in the Data Booklet. page xiv: Percentage of Minerals in Igneous Rocks 2002 b) Explain why rock Z is finer-grained than rock Y. Use the following diagram to answer all parts of question 1. 3 U-shaped valley 2 X c) Igneous rock Y contains 30% dark ferromagnesians and 60% white plagioclase feldspar. What is the name of this rock? Country rock 4 sea Igneous rock Y river d) What is the name of the geologic structure formed by igneous rock Z? 1 5 Igneous rock Z 1. a) Complete the table below by describing the processes that occur at the numbered locations in the diagram above. An example is given for number 1. REFERENCE DATA BOOKLET For question 1e), refer to the following in the Data Booklet. page viii: Photograph 9 e) Photograph 9 shows pyroclastic material found at location X in the diagram. Describe how this pyroclastic material formed. Number Process 1 Example: molten material rises 2 3 4 5-20 - - 21 -
PART B: WRITTEN RESPONSE 2001 Use the following diagram to answer question 3. 2001 Value: 45 marks INSTRUCTIONS: Suggested Time: 55 minutes Answer each question in the space provided. You may not need to use all of the space given. 1. Oxygen and silicon are the two most abundant elements in the earth s crust. Support this fact using your knowledge of the abundance of common minerals and their composition. REFERENCE DATA BOOKLET For question 2, refer to the following in the Data Booklet. page viii: Photograph 11 2. a) Photograph 11 shows a cut section of a metamorphic rock specimen. Suggest an appropriate name for this rock and its parent. Metamorphic rock: Parent rock: b) Describe evidence from the photograph that suggests this rock was metamorphosed. Sedimentary rock 1 2 Metamorphic rock 2 1 3 LEGEND Process 1: Process 2: Process 3: Igneous rock 3. The rock cycle diagram above shows the relationships among the three major rock types. The diagram is missing information which describes the processes that change one rock type into another. In the space below, provide a complete description for each of the three processes. (6 marks) Process 1: 3 2 1 3 Process 2: c) Describe a typical environment in which the parent rock would form. ( 1 mark) Process 3: - 24 - - 25 -
2000 2000
2000 Use the cross-section diagram below to answer question 3. 1999 3. a) Describe two features, visible in the cross section, which show that the contact between rock unit Y and the shale is an erosion surface. i) ii) - 24 -
b) The fine-grained rock unit X has been identified as a lava flow. PART B: WRITTEN RESPONSE 1998 i) Explain how the gas bubbles present show that rock unit X is not a sill. Value: 45 marks INSTRUCTIONS: Suggested Time: 55 minutes Answer each question in the space provided. You may not need to use all of the space given. ii) Describe one other piece of evidence that could be used to show that rock unit X is not a sill. Use the following partial, simplified, rock cycle diagram to answer question 1. PROCESS 1 (Example) c) Rock unit Z shows a difference in crystal sizes across its width. i) Describe a specific location where the smallest crystals would be found and explain why they would be found there. Location: Metamorphic Rock Magma Explanation: PROCESS 5 PROCESS 2 d) Describe a change that could be observed in the texture of the limestone at its contact with rock unit X. Sedimentary Rock Igneous Rock PROCESS 4 PROCESS 3 Sediment - 25 - - 24 -
1. The diagram shows the major classes of earth material that are part of the rock cycle. Complete the following chart, in detail, by naming and describing four of the major processes which drive the rock cycle. Give details about the geological environment where each process would occur. Name and description of the process 1998 Geologic details about the environment where the process would occur c) PROCESS 4 Name and description of the process 1998 Geologic details about the environment where the process would occur EXAMPLE PROCESS 1 Fusion and Melting The rock has been heated to such a high temperature that it has started to melt. The process occurs deep in the earth s crust or in the upper mantle where the temperature is sufficient for melting. a) PROCESS 2 d) PROCESS 5 b) PROCESS 3-25 - - 26 -
REFERENCE DATA BOOKLET Refer to page iii of the Data Booklet. Use the Geological Map to answer question 2. 1998 Value: 40 marks PART B: WRITTEN RESPONSE 1997 Suggested Time: 50 minutes 2. a) Describe one change you would expect to see in the fossiliferous limestone due to contact metamorphism near the granite intrusion. INSTRUCTIONS: Answer each question in the space provided. You may not need to use all of the space given. 1. a) The chemical composition of molten rock from a deep magma chamber may be changed by a number of different processes as it moves upward towards the surface. Describe how two of these processes, Wall Rock Assimilation and Fractional Crystallization can change the chemical composition of the magma. b) What changes in crystal size would be observed by a geologist as she walked the 200 metre section from X to Y across the granite? Wall Rock Assimilation: Fractional Crystallization: b) If the changes to the composition of the molten rock resulted in a silicic (felsic) magma, what type of eruption would result when the magma reached the surface? Score for Question 1: 1. (4) - 27 - - 26 -
1997 1996 Use Photograph 7 of an igneous feature on page ix of the Data Booklet to answer question 2. Use Photographs 7 and 8 on page viii of the Data Booklet to answer question 8. 2. a) Name the dark angular feature shown in the centre of Photograph 7, and describe how this feature forms. Name of feature: Description of formation: 8. Photographs 7 and 8 show two common types of surface lava flows. a) Name each surface type. Photograph 7 surface type: Photograph 8 surface type: b) Name the composition of the lava which typically forms these two surface types. b) What information can this igneous feature provide geologists? Score for Question 2: 2. (3) c) Name the flow feature that would form if this type of lava were to erupt under water. Score for Question 8: 8. (3) - 27 - - 27 -
Value: 40 marks INSTRUCTIONS: PART B: WRITTEN-RESPONSE Suggested Time: 50 minutes Answer each question in the space provided. You may not need to use all of the space given. 1995 2. a) Describe two observable differences between intrusive igneous rocks and clastic sedimentary rocks. Difference 1: 1995 Use Photograph 4 on page vii in the Data Booklet to answer question 1. Difference 2: 1. a) Name the rock texture illustrated. b) Metamorphic rocks require an increase in temperature and/or pressure in order to form. Answer the following to explain the conversion of sedimentary rock to metamorphic rock. b) Referring to evidence that you can see in the photograph, describe how the texture of this igneous rock was formed. 0 Score for Question 1: 1. (3) i) Describe a method by which the temperature could be increased. ii) Describe a method by which the pressure could be increased. Score for Question 2: 0 2. (4) - 20 - - 21 -