Short Answer Marking Guide for Metamorphic Rocks and Ecosystems

Section Two: Short Answer (60%) 125 marks This section has 10 questions. Answer all questions. Write your answers in the spaces provided. Spare pages are included at the end of this booklet. If you need to use the space to continue an answer, indicate in the original answer space where the answer is continued, i.e. give the page number. Fill in the number of the question that you are continuing to answer at the top of the page. Suggested working time: 100 minutes. 16. Metamorphic rocks have been changed due to the actions of heat and/or pressure. 9 marks a. Complete the table below for some common metamorphic rocks. (5 marks) Texture Minerals Name Crystalline, granular Calcite Marble Foliated or schistose Mica, garnet Schist Banded or gneissic banding or large crystalline grains Quartz, feldspars, Sillimantite, Kyanite Gneiss b. Describe the process by which shale is turned into gneiss. Explain changes to texture and mineralogy. (4 marks)  Increased temp and pressure due to Regional metamorphism (1)  Minerals become unstable then form new minerals at higher temperatures and pressure (1)  Flaty platy (perpendicular to compression stress)/ elongate crystals due to DIFFERENTIAL STRESS (1)  Shale  Slate  Phyllite  Schist  Gneiss (1) 1

17. A geologist created the map below of an area of interest. 15 marks a. On the axes provided draw a geological cross section along the line X-Y (including any topography). Interpret the sub-surface geology down to sea level and label all features. (7 marks) 2

1 mark for each of (up to 7)  appropriately labelled y-axis  contours smoothed out  vertical dyke  basalt on top (extrusive igneous rock)  unknown shape of granite body below surface  sediments dipping at correct angle (and direction)  contacts correct at surface. b. Some of the sedimentary rock in the area was noted to be recrystallised. Explain how this occurred and name TWO rocks formed from this process. (4 marks) Contact metamorphism (1) Heat from the granite body (1) – or basalt flow or from the dyke Quartzite, marble or hornfels Limestone  Marble due to contact metamorphism (from basalt flow) (1) Sandstone  Quartzite due to contact metamorphism (from Dolerite intrusion) (1) 3

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c. Complete the stratigraphic column, including any events, for this mapped area. (4 marks) weathering and erosion basalt (weathering and erosion) dolerite dyke granite intrusion causing uplift (folding) shale limestone shale sandstone 18. A team of environmental scientists working across a landscape draining into a river ( river catchment ) need to identify important components of the ecosystem. Assist them by correctly classifying the following services into their most suitable ecosystem service categories: 13 marks a. Assist them by correctly classifying the following services into their most suitable ecosystem service categories: (6 marks) Freshwater supply Air quality Biological control Nutrient cycling Production of Oxygen Carbon sequestration Provisioning Services Regulating Services Supporting Services Freshwater supply Air quality Nutrient cycling Carbon sequestration Production of Oxygen Biological control b. They identified a section of the river, near faming land, that was prone to ‘fish kills’ and noted that it coincided with times that the algae population boomed. 4

i. Describe the cause of these algae population booms and subsequent fish kills. (4 marks)  Eutrophication  Increased nutrients in waterways (from crop fertiliser/manure run-off)  Algal population inc rapidly blooms, limiting light at depth decreased plant production at depth  When plants die, decomposers inc BOD -> fish deaths ii. Suggest ways in which these events can be prevented in the future. (3 marks)  Reduce fertiliser use  Use of slow-release fertilizer  Prevent nutrient run –off – divert with drains/contour banks  Process water to reduce nutrient load 5

19. As part of the monitoring of modern climate change, carbon dioxide is measured (as dry air mole fraction) at the Mauna Loa Observatory, Hawaii. The average annual data is provided below for the last ten years 12 marks Year Mean CO 2 (ppm) 2006 382 2007 384 2008 386 2009 387 2010 390 2011 392 2012 394 2013 396 2014 399 2015 401 (NOAA, 2016) a. Draw a graph for this data below (a spare grid is at the back of this booklet) (6 marks) 6

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b. Explain how carbon dioxide in the atmosphere contributes to the Greenhouse Effect. Use a diagram in your answer. (6 marks) Diagram representing the Greenhouse Effect  incoming solar radiation (short wave)  may be reflected or absorbed by Earth’s surface  surface warms and radiates IR (long wave radiation)  greenhouse gases such as CO 2 absorb LWR and re-radiate back to Earth  the higher the carbon dioxide concentration in the atmosphere the more heat that is trapped  reduces net loss of energy to space so temperature increases c. Name TWO possible anthropogenic sources for this carbon dioxide. (2 marks) Burning of fossil fuels Land clearing Burning rainforest Cement making 7

20. The number of large, hot fires have been increasing across Australia in the past decade. 7 marks a. Describe the impact on the biosphere of a high intensity bushfire. (4 marks)  Large losses of animal – unable to shelter or flee fast enough  Seedlings and young plants have no resistance -> destroyed even older plants, tolerance to fire may not survive the intense heat  No regeneration as seedbank lost and no plants to recolonise  Lost biodiversity and  Lost ecosystem productivity &/or resilience  Loss of habitat b. El Nino and La Nina events modify the weather in Australia. Which of these is associated with increased risk of bushfires? (1 mark) El Nino c. Explain how low intensity bushfires can be beneficial for an ecosystem, using an Australian example. (2 marks) Many Australian native plants are tolerant of bushfires or need them for germination (1) Example (1 )Any of: Eucalypts have lignotubers which spout soon after a fire OR Banksia have seed pods that only release by heat of fire OR some Wattles have seeds that need the heat from fire to germinate 8

21. Australia can experience a climatic pattern called a La Nina event. 8 marks a. Describe two weather outcomes that result for Australia as a result of a La Nina period. (2 marks) Lower average temperatures (day) (1) higher (night) Higher rainfall -> flooding (1) Easterly winds (Trade Winds) stronger (1) The opposing weather pattern is termed El Nino . The main two water bodies involved in this weather pattern are the central and western Pacific near Australia and the eastern Pacific near South America. 9

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b. Describe two weather outcomes that result for Australia as a result of an El Nino event. (2 marks) Higher average temperatures (1) lower (night) Lower rainfall -> drought (1) Easterly winds (Trade Winds) weaker to reversed (1) c. Briefly explain how these two water bodies are affected in an El Nino event. (2 marks) Central and western Pacific near Australia – becomes cooler than normal (1) Eastern Pacific near South America– becomes warmer than normal (1) OR decreased upwelling of nutrient rich cold water d. Explain two possible causes for the change in the conditions in these two water bodies. (2 marks) Weakening to reversing of Trade Winds Weakening to reversing of Walker Circulation Lessening of the Humboldt Current 10

22. The Earth’s climate system is large and complex, with many components. 12 marks a. Using an example, describe how climate change can impact an ecosystem (4 marks) Changes in seasons upset lifecycles -> decreasing populations Species have tolerance limits/preferred niches Increased range of pest species Rate of CC too fast for species to adapt May migrate Reduction in biodiversity Eg coral bleaching and deaths due to rising water temperatures Too fast for spp to adapt Impact on food chain/habitat provision Other spp migrate or die b. Using an example, describe how climate change can impact the weather conditions in the atmosphere (4 marks) Inc surface temperatures -> inc evaporation Inc water vapour concentration and cloud distribution Inc evaporation ‘fuels’ storms incl more extreme events like hurricanes and cyclones Changed weather patterns incl. wind direction and strength (Inc in wildfires put aerosols and particulates into atmosphere) c. Using an example, describe how climate change can impact the hydrosphere (4 marks) In areas of low rainfall aquifers are recharged more slowly -> may dry up Inc evaporation inc water vapour in the atmosphere More precipitation in some areas Glaciers melting Expanding oceans (warmer water) raise in sea levels Decreased glaciers and sheet ice -> dec albedo 11

23. Fossils fuels are an important non-renewable energy resource. 10 marks a. Explain how oil and gas are formed (4 marks) Plankton and oceanic micro-organisms die, accumulate on ocean floor and are quickly buried (1) Little to no oxygen (1) Continued burial increases heat and pressure (1) ‘Cracking’ of organic compounds OR Formation of kerogen ->y oil and gas (1) b. Describe a structure in sedimentary rock that results in oil and gas reservoirs. Include a labelled diagram in your answer. (4 marks) Name of trap Impermeable cap – shale Reservoir rock – sandstone Source rock – marine shale Enough depth to provide thermal maturity Oil and gas rise as less dense than water c. Describe how oil and gas are extracted (2 marks) Wells are drilled 3-6 km into gas – Pumps are used if pressure is inadequate to extract oil 24. On the 24 th of August, 2016 a 6.2 magnitude earthquake struck ten kilometres south- east of Norcia, Italy. This earthquake led to a large number of fatalities and massive economic losses. The USGS recorded shaking intensities ranging from not felt to very strong in the region with much of the area experiencing moderate shaking. 11 marks 12

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Source: USGS a. This region is influenced by oceanic-continental convergence (east to west), continental-continental convergence (to the north) and divergence to the west. This earthquake, however, was caused by an intraplate normal fault. Using your understanding of plate tectonics explain how this earthquake event may have been generated. (4 marks)  Crust forced apart by stress  Friction prevents movement across fault  Forces build until overcome friction -> movement (earthquake)  Energy released sends out seismic waves = earthquake 13

b. Explain any possible factors that may have contributed to the devastation of this earthquake. Why did this particular earthquake cause so much damage? (4 marks)  6.2 is a relatively high magnitude earthquake  Location of focus (shallow)  The epicentre of this earthquake is in the middle of many towns = highly populated  Buildings may not have been designed to withstand such earthquakes  The rocks in the region may have had weakness c. Explain THREE strategies to reduce the impact of future earthquake events in this region. (3 marks)  Legislate a requirement for ground shake resistant structures in new buildings  Retrofit reinforcing structures into older buildings  Provide public information about how to prepare for, and deal with, an earthquake 25. For a renewable energy source that you have studied, outline the following: 10 marks a. How the energy is generated or stored in the renewable source (2 marks) b. How the energy is converted to a useable form. (4 marks) c. Explain THREE factors that impact the cost-effectiveness of this energy resource. (4 marks) 26. Nickel sulphide ores are a significant economic resource of Western Australia. Explain how immiscible liquid separation contributes to the formation of a nickel sulphide ore deposit. 6 marks  Ultramafic diapir high in Nickel ions  Rises through country rock rich in Sulphur  Sulphur dissolves and is incorporated into magma  When Sulphur levels saturate droplets of Sulphur form  Sulphur droplets incorporate (scavenge) the Nickel ions to form Nickel sulphide  The Nickel sulphide is then concentrated on the bottom of the magma chamber due to gravitational settling forming the ore 14

Section Three: Extended response (30%) (30 Marks) This section contains three (3) questions. You must answer two (2) questions: the compulsory question (Question 27) in booklet 3 and one (1) of the other questions (Question 28 or Question 29) in booklet 4. Remember to write your name and the question answered at the top of the booklet. Suggested working time: 60 minutes. 27. The Earth’s climate has fluctuated over millions, even billions, of years. These changes may be inferred from geological and hydrological evidence. 15 marks a. Explain how changes in oceanic circulation resulting from the plate tectonic super cycle can contribute to global climate change. (3 marks) The Great Ocean Conveyor circulates heat across the globe (1) More dense (either due to low temp or high salinity) water sinks (1) Separated continents channel currents and increase the efficiency of heat flow to poles. (1) b. Describe how ice core and isotopic data can be used to determine past climate. (5 marks) Bubbles of gases trapped in ice cores can provide a snapshot of the composition of the atmosphere in the past (1) The concentration of greenhouse gases, like carbon dioxide and methane, can be determined (1) Isotopes of oxygen provide a measure global temperatures (1) Oxygen-16 is relatively lighter than oxygen-18 so water with oxygen-16 more readily evaporates. Water vapour with oxygen-18 more readily condenses (1) Ratios of O-16/O-18 and carbon dioxide concentration are correlated to show climate change and causation (1) c. Outline how climate change can impact species distribution, using examples to support your answer. (4 marks) Special have tolerance limits of temperature, rainfall… within which they can survive and reproduce (1) If these limits are exceeded in a region, species will either migrate or decline and become extinct (1) And 1 for each of two examples (2) e.g. As temperatures rise and rainfall decreases the ideal ‘growth belt’ for different plants may move. For example the ideal growth region in WA – the Wheatbelt - is currently moving south. As plant populations ‘move’ (in fact the plants on the fringes suffer/die and those on the advancing edge of preferred conditions colonise) so too do the animal populations that rely upon them. For example populations of numbats are being found further south in WA 15

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Fish populations that move with cold currents, providing oxygen and nutrient rich waters, will divert migratory pathways if these currents are diverted, or supressed, by climate change. d. Explain the link between climate change and the extent of ice sheets. (3 marks) Warming climate -> ice sheets retreat as warm waters melt the sheets/ Cooling climate -> ice sheets advance as more ice is formed (1) Sets up a positive feedback loop by (1) - decreasing surface albedo (ocean waters are less reflective than ice) -> further warming - increasing the surface albedo (reflective ice) -> further cooling (1) 16

Answer question 28 or 29. 27. There are relatively small amounts of fresh water available for biological processes globally. 15 marks a. A major source of water for WA agriculture and Perth City is groundwater, contained within aquifers. Describe in detail using TWO examples for each, how human activities may impact: i. the availability of this groundwater (2 marks) Land clearing may result in a rising local water table (unconfined aquifer) (1) Use of water for irrigation, manufacturing etc. leads to over extraction which depletes groundwater (1) ii. the quality of this groundwater. (2 marks) Land clearing may result in the contamination of groundwater with salt as water table rises (dryland salinity) (1) Salt water ingress due to over use of aquifer Lowering of water table near coast (below sea level) may result in saltwater influx (1) Nutrient or chemical runoff from market or domestic gardens, washing cars (1) Water treatment plant improving water quality (1) b. The extraction of mineral resources may impact hydrologic (water) systems. Using the extraction of GOLD. i. Describe how an aquifer can be contaminated (2 marks) Leachate containing cyanide bearing tailings Flooding causing run-off from cyanide-bearing tailings dams ii. State ONE example of how aquifers are protected and monitored when extracting this resource. (2 marks) Use of plastic linings and impervious sealing layers in tailings dams OR Use of drainage ditches around tailing dams to prevent flooding (1) Observation wells to monitoring groundwater (1) c. Desalination is a method currently used to increase the supply of potable water to Perth water users. iii. Describe the desalination process (2 marks) 17

Pressure is used to force salt water to pass through a semipermeable membrane to separate salts from water (1) Reverse osmosis (1) iv. Discuss two potential negative environmental impacts of this process (2 marks) Ecosystem seawater extracted from (organisms get trapped on intake structures) Disposal of hypersaline brine – toxic Carbon dioxide emitted from high energy use process (if FF generated) d. Our use of water can be measured within our ‘ecological footprint’. What is an ‘ecological footprint’ and why is it important. (3 marks) Measure of the negative impact humans have on the environment (1) Sum of the land required to produce the food, fibre, energy, etc and to absorb the wastes produces and space for infrastructure incl habitat destruction (1) It helps us to understand our impact on the planet and if our current practices are sustainable (1) OR 26. Plate tectonic processes shape our world and impact our climate and biosphere. 15 marks a. Explain how ONE of, earthquakes, volcanic eruptions or tsunamis, are generated by plate tectonic processes (use a diagram to support your answer). (4 marks) Earthquakes  Plate boundaries have edges that are rough. Edges remain stuck while rest of plates move, building up elastic potential energy  Energy is released in seismic waves when it has built up enough to overcome friction between two edges and the two blocks of the Earth suddenly slip passed one another OR  Earthquakes are usually caused when rock underground suddenly breaks along a fault.  This sudden release of energy causes the seismic waves that make the ground shake. 18

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OR Volcanoes can be formed in many tectonic settings – eg subduction zones  The subducting crust provides materials such as sediments, water etc. on top of it which are mobilised/melted by inc pressure and temperature..  This material moves up to fuel volcanoes – within mountains formed by the compressive forces of colliding plates. The magmas that accumulate within these volcanoes may be quite viscous (silica rich), collecting gases and erupting explosively. 19

OR Volcanoes formed at Hot spots  Occur intraplate (away from tectonic plate edge) above a mantle plume  High heat and pressure from plume melts rock above plume and magma rises through cracks in lithosphere and erupts Tsunamis  Caused by undersea earthquakes or landslides  (may also be caused by a large meteorite hitting the water)  This generates force to lift a column of water which becomes a Tsunami b. Describe how volcanic emissions impact climate and weather. (4 marks) Ash and particulates – particularly from sulfuric gases - from stratovolcano eruptions may circulate in the stratosphere (1) Increasing albedo reducing temperatures.Short term effect (1) For a large eruption this may cause a ‘volcanic winter’ – ((e.g. Mt Pinatubo dropped global temperatures by ~0.5° from 1991-1993)) (1) 20

Volcanoes (both shield and stratovolcanoes) emit large amounts of greenhouse gases such as carbon dioxide and water vapour (1) These contribute to the greenhouse effect and overall warmth – times of high volcanic activity – e.g. basalt floodplains may result in warmer climates (1) c. Explain how a shield volcano eruption may impact the biosphere as compared to a stratovolcano eruption. (4 marks) Shield volcano major hazard = lava flows = vegetation lost (1 mark) Stratovolcano major hazards = rock bombs, pyroclastic flows, lahaars etc. = vegetation lost, animals buried or asphyxiated etc. (1 mark) Shield volcanoes are fuelled by magmas with relatively lower viscosities (mafic) (1 mark) These lower viscosity magmas readily release gases and therefore pressure – stratovolcanoes can build up in pressure resulting in explosive eruptions (1 mark) d. For ONE of, earthquakes, volcanic eruptions or tsunamis, outline the monitoring that allows prediction of the likely occurrence of the earth hazard selected. (3 marks) Earthquakes  local seismic activity is monitored  changes in groundwater levels  changes in emission of Radon gas OR Volcanic eruptions  tiltmeters used measures movement on flanks,  changes in geomorphology (deformation/bulges)  changes in emitted gases  changes in groundwater flow (and chemical composition)  local seismic activity is also monitored. OR Tsunamis  seismic activity is monitored  sea level changes – sea-level gauges  deep ocean detection buoys END OF EXAMINATION 21

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EES 12 Sem 2 2016 Marking Guide Section 2 and 3

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