GEOL 1006 & 1021 Fall 2023 Review Guide PDF

GEOL 1006 and GEOL 1021 Final Exam - REVIEW GUIDE – FALL 2023 Topics covered during the term: Basic information (composition, age, etc.) Volcanism The scientific method Earthquakes and Tsunamis Plate tectonics Eart...

GEOL 1006 and GEOL 1021 Final Exam - REVIEW GUIDE – FALL 2023 Topics covered during the term: Basic information (composition, age, etc.) Volcanism The scientific method Earthquakes and Tsunamis Plate tectonics Earth’s Interior Minerals Energy Resources Rocks and the rock cycle Meteoritic Impacts Deformation Mineral Resources (fundamentals only) Geologic time Suggestions on how to use this guide: 1. Go over the slide decks with this list. 2. Identify slides related to what is mentioned below 3. Understand the concepts. Yes, you will need to memorize some terminology, but this guide is meant to highlight what is most important. 4. I tried to bold key aspects as much as possible, but it does not mean the rest is to be ignored 5. The answer key to the exam is posted on D2L. Reviewing your exam with the answer key is also a good way to prepare. Some of the questions will be similar. Introduction and basic concepts Earth layers (from crust to core; inner and outer core) General aspects of time scale (age of the planet; major markers and assumptions) including o Oldest known rocks are not as old as Earth. o Age estimates based on assumption that all solar system has the same age (therefore age of Earth is determined from age of meteorites) o Other significant events: § Early Earth had a CO2 rich atmosphere, photosynthesis and production of plant matter eventually caused rise of oxygen content (~2.7 billion years ago; this is known as the “Great Oxygenation Event”) o See section on geological time for other aspects. The three main geosystems, components, and interactions: o Plate tectonic system (drives earthquakes, volcanoes, amalgamation of continents, etc.) o Geodynamic system (movement of inner core relative to outer core) generates Earth’s magnetic field. o Climate system (atmosphere-hydrosphere interactions with surface of the solid Earth) key to understand anthropogenic climate change (more on that section) Location of the layers in the Earth is obtained from seismic profiles. Major seismic discontinuities indicate: o Changes in composition (e.g., silicate mantle to iron-nickel core) o Liquid-solid transitions (e.g., between solid inner core and liquid outer core) Outer core determined as liquid because S-type seismic waves cannot move through it (explained in detail later) Page 1 of 11 Earth composition Cannot be determined directly (deepest drillhole is ~ 12 km in depth, insufficient to sample the planet directly) Some samples of the interior of the planet are brough up to surface by volcanic eruptions or by tectonic processes (samples of the upper mantle are available) Composition of the planet estimated on the assumption that it matches the solar system (minus volatiles, such as hydrogen and helium, which escape) o Solar photosphere can be used to estimate the ratio of some major elements. o Of all the varieties of meteorites available SOME match the solar photosphere element ratios reasonably well (carbonaceous chondrites, in particular the Ivuna-type) o Detail measurement of those meteorites (CI chondrites) is how the BULK composition of the planet is estimated. o Next step is to separate what is retained in the core and what goes into the mantle and crust. Core is made of iron and nickel, plus minor amounts of a lighter element (could be S, Si, O, but not well known). The existence of Fe-Ni meteorites is one way to validate this is a reasonable assumption. Mantle and crust are made mostly of Si, O, Mg, Fe, Ca, Al, K, Na (know these eight elements!) The main difference between crust and mantle is that the mantle has more Mg and less Al. Plate tectonics: Happens because the Earth is losing heat and because of density contrast between three entities: mantle (denser), continental crust (less dense), oceanic crust (intermediate density, meaning will remain on top of the mantle for some time, but eventually subducts back into the mantle) Know types of plate boundaries (convergent, divergent, transform faults) and relative rates of movement (roughly between 1.5 and 15 cm) Know types of interaction: o Continent-continent collision (e.g., Himalayas range) o Subduction (oceanic plate under either oceanic or continental plate; examples: west coast of America; Indonesia, Caribbean islands) o Transform faults (e.g., San Andreas system, California) o Rifting (in continental crust or in oceanic crust; examples east African rift, mid- Atlantic rift) Be familiar with location of some examples (e.g., some given in the slide deck, also above) Roughly 14 major plates and about 38 small plates moving constantly relative to each other. o Major seven: Pacific, Africa, Antarctica, N. America, Eurasia, Australia, S. America account for ~80% of total area o The next seven add to ~15%, so 14 plates account for 95% of the total area. Spreading centers (e.g., Mid Atlantic) is where most crust is produced (as oceanic crust). We do not see it because it happens under ~ 4,000 m of water, but these are areas of major production of magmas and igneous rocks. Subduction zones is where most crust is consumed (oceanic plates “recycled” back into the mantle, so they are “consumed” in the sense that are no longer part of the Earth surface) Collision zones produce some “shortening” mostly because of stacking of continental crust. Page 2 of 11  Result of billions of years of plate tectonics is that continental crust has the oldest rocks. In contrast most oceanic crust is not older than 200 million years Mantle convection is the engine for plate tectonics. Driven by heat produced by radioactive decay of mainly three elements: U (uranium), Th (thorium), K (potassium) Wilson Cycles and supercontinents: Continuous breakup and amalgamation of continental crust (and accretion of newly formed crust) One cycle: from breakup of previous supercontinent to amalgamation of the next Roughly five known cycles (you don’t need to know names or ages of each one) Natural consequence of plate tectonics Means current configuration of plates is changing and likely with lead to a new supercontinent millions of years in the future (e.g., the Mediterranean Sea is disappearing, the Pacific Ocean is getting smaller, Africa is breaking up, etc.) Importance: current geology anywhere on Earth is the result of millions (and billions) of years of geological activity (see geological maps of North America and Sudbury). Mapping existing rocks and reconstructing the processes that formed them is one of the main tasks of geologists (refined continuously, more detail, better techniques, new hypotheses of origin, etc.) Continental Drift (hypothesis): Wegener’s idea (early 1900s) – based on match of continent outlines AND fossil and rock records. Discarded because no mechanism known to cause movement of continents at the time. Revisited when mid-ocean ridges were discovered in the 1950s and 1960s. Foundation of the Plate Tectonic theory (robust and continuously validated with new evidence) Mantle Plumes (hot spots): Unrelated to plate tectonics Assumed to be caused by core-mantle interactions (hot spot source) Produce volcanic systems away from plate boundaries (e.g., Yellowstone calderas, Hawaii) May coincide with spreading centers (e.g., Iceland) Initial emplacement (plume head) can generate large volumes of magma. Scientific method Know the formal definition of hypothesis and theory. Be aware that “theory” is commonly used to imply a wide range of things (from wild hunch, to hypothesis, to real theory) In essence science is just a system that aims to rigorously test many hypotheses. If a hypothesis becomes dominant and supported by available evidence it eventually may become a theory (plate tectonics, from the continental drift hypothesis is a great example) Know the meaning of accuracy and precision (and the problem of measurements that are precise but not accurate: misguided sense of confidence if unaware of the “precision bias”) Precision bias: how far from the true value the mean values of measurements are. There will be no questions in the exam about denialism and logical fallacies, but those are perhaps some of the most useful aspects outside this course. Page 3 of 11 Minerals Know the definition of mineral (5 aspects) Be able to spot substances that may or may not be minerals. Main aspect of chemical bonds: dictate the physical and chemical properties of minerals (habit, luster, cleavage, ability to dissolve in water, etc.) Silicates as most important class of minerals Silica tetrahedron as the building block of silicates (“tetrahedral shape” because ionic size of Si fits inside a stack of four oxygen ions) Basic families of silicate minerals and their silicate structure (from isolated, to chains, to sheet, to framework) Know some common minerals (quartz, plagioclase, micas, amphibole, pyroxene) and how they relate to structure. Physical properties to identify minerals (habit, luster, cleavage, hardness, color, etc.) Know minerals that are useful to identify rock types. Examples we saw in class: o Halite and gypsum – evaporitic environments (sedimentary) o Olivine – almost always igneous o Garnet, kyanite – metamorphic origin Know names of other mineral groups and some examples (e.g., to know they are mineral groups and not rock types). Oxides (hematite), sulfides (pyrite), halides (halite), carbonates (calcite) Know enough of the hardness scale to identify proper order of hardness (top two and bottom three in hardness scale, familiar with names in between). Should be able to place 3 minerals in order of increasing hardness. Be aware the color can be misleading (same mineral can have many colors; different minerals can have similar color and luster) Rocks and the rock cycle Types of rocks are defined by how minerals are formed. o Sedimentary: by surface processes o Igneous: from cooling of a silicate melt (magma) o Metamorphic: transformations due to pressure and temperature without melting Links between rocks (the “rock cycle”) see expanded version in slide deck and know limitation of the standard version popularized in introductory books. For example: o Most magmas are not the product of melting of metamorphic rocks. o In fact, most magmas are produced by partial melting of the mantle (which formed early during earth history during accretion of the planet) o The classic “rock cycle” only shows clastic sedimentary rocks but a real version should include rocks formed by biogenic processes (such as coral reefs), or chemical sediments (example: evaporites) Rock origin is closely related to plate tectonics (e.g., sediments are deposited in basins; spreading centers and subduction zones the areas with major magmatic activity; continent collisions the main places for regional metamorphism) Almost all rocks that we see at surface formed at depth and are now exposed by a combination of UPLIFT and EROSION Page 4 of 11 Sedimentary rocks Surface processes. That’s why classification involves dissimilar things such as biological, chemical, and clastic origin (surface processes is the common link) Main group (by volume): clastic sedimentary processes: from uplift (exposure of any type of rock) to burial and diagenesis (compaction and cementation). Involves other processes in between: o Chemical and physical weathering (effect depends on mineral stability; for example, things like quartz and garnet are a lot more resistant to chemical weathering than other silicate or minerals like halides and sulfides) o Erosion, transport, deposition are part of a continues process (moving material from one place to another) o Preservation of minerals is a function of intensity of weathering and transport distance. A basin is essentially any place on Earth where sediments can accumulate (the oceans being the ultimate place of rest) Clastic sediments are classified mostly by grain size (mudstone, siltstone, sandstone, conglomerate) Important to be aware of the differences between physical and chemical weathering: o Physical weathering only affects particle size (minerals become smaller and rounded) o Chemical weathering affects composition (minerals dissolve releasing ions into aqueous solutions, remaining elements transform into new minerals). One of the best examples is bauxite (a mixture of Al oxides). Bauxite may have started as a granite, but Na, K, Si, were removed by chemical weathering leaving mostly Al and Fe oxides. Organic matter also undergoes burial and diagenesis. This is the origin of fossil fuels. o Optimal conditions to produce oil and gas: oil and gas “windows” (mostly relates to temperature) o If below the window: immature source rocks o If above the window: oil becomes gas, gas becomes graphite. Evaporites: occur when rate of evaporation is higher than influx of water. Large evaporite formed during restricted inflow conditions (examples: Mediterranean Sea several millions of years ago; also, potash deposits in Saskatchewan) Biological sediments: minerals that have inorganic equivalents (e.g., carbonates, quartz) but produced by living organisms. Best example are coral reefs (take CO2 and CaO from seawater to form carbonate shells). Some organisms make their shells out of silica (quartz) Igneous rocks (some of this in the chapter of volcanism) Definition of magma and lava: not as simple as “molten rock”. Better definition of magma: a mixture of silicate melt plus crystals plus dissolved gases in the melt. Magma if underground, lava if magma reaches the surface (surface understood as solid earth lavas flowing at the bottom of the ocean are still lavas even if under 4,000 m of water). Types of igneous rocks: Intrusive vs. extrusive; felsic vs. mafic. Know basic examples (basalt, gabbro, rhyolite, granite) and how they link (plutonic, volcanic, mafic, felsic) Where do they form: o Largest production of igneous rocks: spreading centers (mid-ocean ridges) o Subduction zones (volcanoes are only the surface expression, a lot of magma does not reach the surface) o Mantle plumes (we tracked the evolution of the system in Iceland, which did not end in eruption, so far) Page 5 of 11  Main mechanism of magma generation: partial melting. Relevant for rock cycle because there are two paths: o Partial melting of the mantle produces basalts (not a metamorphic process). o Partial melting of the crust produces granitic rocks (standard “rock cycle”: top end of metamorphism produces melting) Metamorphic rocks Concept of metamorphism: changes in minerals present due to increase in pressure and temperature (new minerals form) Does not involve melting (melting can eventually happen but that would be the transition to an igneous process) New minerals appear (example garnets from a rock that started as mud on a lake) due to changes in pressure and temperature (higher pressure pro, development of foliation Reference metamorphic P-T grid shown in class: rough range in temperature (up to 1000 °C) and pressure, best if thought about depth (up to 40 km). Good framework to understand low- grade, intermediate grade, high grade. The same material can form multiple metamorphic rocks. The example used in class is a shale (sedimentary) becoming a slate, then phyllite, schist, gneiss (migmatite is a rock already experiencing partial melting. You should be able to know the slate-phyllite-schist-gneiss sequence and know: o Which ones are low-grade vs. high grade? o The relative increase in grain size and foliation (e.g., fine grained and platy/parallel cleavage of slates vs. banding and larger grains in gneisses) Be aware of other types of metamorphism, but we will emphasize only reginal metamorphism (bullet points above) Deformation (how rocks respond to applied forces) Two different styles of behavior of materials: o Ductile (bending: folds) o Brittle (breaking: faults) Geometry of geological structures can be represented by orientation of planes. At any location, any plane can be represented/described is we know two things: o Strike: (direction of a horizontal line within that plane) o Dip: maximum inclination of that plane and to what side of the strike is the dip direction Change from brittle to ductile depends mostly on temperature of material (and heat increases with depth) Not all fractures are faults (faults require movement of material on each side of the plane) Faults typically have displacement along strike and dip, but in general they are classified as: o Normal: if block on top of fault drops o Reverse: if block on top of fault is stacked on top of the bottom block (moves upwards) o Strike-slip (if movement is along strike of the fault and there is little to no vertical movement) Folds require description of several elements (simplified as planes): o Two limbs o Axial plane (plane that passes through the “hinge” of the fold) (often also plunging angle of the fold Page 6 of 11  There are various ways to describe folds. Know geometry of limbs and fold axis of synclines and anticlines Geologic time (relative and absolute time, geological time scale) Two ways to describe time: o Relative time: order of multiple events (e.g., event “A” earlier than event “B”) o Absolute time: when (e.g., event “A” 67 million years ago) Geological time scale uses a combination of both (e.g., major extinctions from disappearance of fossil in the geological record, then absolute ages bracketing when the events occurred) Relative time uses principles of stratigraphy (original horizontality, superposition, faunal succession). Only applies to sedimentary sequences. Other markers of relative time: o Unconformities: sedimentary sequences at an angle to one another (implies uplifting, deformation, and erosion of one sequence before the upper sequence is deposited and compacted) o Cross cutting relationships: things need to already exist before they are cut and displaced. The element being displaced is older than the element causing the displacement (see examples of igneous dikes being displaced by faults and vice versa) Absolute ages require use of radioactive decay. Why? Isotopic decay is not affected by pressure, temperature, or any other thing. Isotopes of one element (parent), decay to isotopes of another element (daughter) at known rates IF concentration of parent and daughter isotopes can be measure in a mineral, then the age of formation of such minerals can be determined. One of the best minerals is zircon. Why: o Starts with only U (parent), so any Pb measured is “daughter.” o Resistant to chemical weathering (so very old rocks still have some) o U-Pb system (uranium-lead) has two clocks, both with different but long half-lives (useful to date old rocks). If the two “clocks” match the obtained ages are more robust Know how to read and understand the diagrams that show proportion of atoms left and half- lives. Integration of absolute ages and relative ages: geologic time scale and main divisions of Earth’s history. Overall concept of geologic time (span: 4.6 billion years). No need to memorize other ages, but have some key reference points in mind: o Rise of atmospheric oxygen (~2.7 Ga; roughly half the age of the planet!) (Ga = giga annum = 1,000 million years; Ma = mega annum = 1 million years) o Major extinctions at 250 and 67 Ma (plus some others) The Earth as part of the solar system is key to understand how the age and composition of the Earth is estimated. Volcanism and volcanic hazards Volcano: any topographic feature that is linked to magmas reaching the Earth surface. The main type is the “stratovolcano”: the cone-like with a truncated top mountain, like Mount Fuji Part of a complex system that is connected to magma chambers below it. Different types of shapes (dictated mostly by viscosity of magma and style of eruption): o Stratovolcano and shield volcanoes, the most important (by volume) Page 7 of 11  o Calderas: when large volcanic eruptions happen (in essence the crater is much larger and most of the volcanic structure is gone) Viscosity of magma (resistance to flow) is a function of composition: felsic magmas are more viscous than mafic magmas (felsic: flow like peanut butter; mafic: flow like ketchup) Felsic magmas typically have more dissolved gases. Release of gas content is what makes eruptions explosive. Many types of styles of volcanic eruptions. No need to memorize names, but know it relates to things like geometry (fissures) and explosivity (Plinian being the most explosive) Seismic activity (and sulfur emission) are the best ways to monitor volcanic activity BUT as Iceland showed this term, predicting location and time of eruption is very difficult. All that can be done is assess risk probability. Major volcanic hazards are not lavas but pyroclastic flows and lahars. o Pyroclastic flows: avalanches of ashes and hot gases (several 100s of °C) (see example of Mount Pelee) – quick but limited to slopes of volcano. o Lahars: mud flows that travel quickly and solidify also quickly (see Nevado del Ruiz example) – could happen away from volcano if there are creeks starting from their slopes Some major extinctions seem associated to very large magmatic events (see mantle plumes and effect of the “plume head”) The Anthropogenic Climate Catastrophe My take: “catastrophe” because “change” is too mild for the consequence we already see. Anthropogenic, because the link to human activity is now undeniable. Effect of “greenhouse gases” is well known (transparent to incoming solar radiation, but reflective to infrared radiation, net effect: more heat is trapped by this blanket) Some climate perturbations are natural and cyclical. Therefore, back in the 1970s and 1980s it was reasonable to question whether the signal (increase in mean global temperatures) was real or caused by human activity. Divergence, over the last 20 years between expected from natural systems only and observed (and modeled) by human activity is among the strongest evidence in any scientific discipline (Not uncommon, in the 60s many geologists refused to believe plate tectonics was real!) Record of climate change over hundreds of thousands of years: preserved in ice cores (trapped air): basic principle is not much different that stratigraphy (older at the bottom), finetuning thickness of ice with age is well beyond the scope of this course (and my current expertise) Volcanic eruption (sulfur emission) causes temporary cooling. So, some mass extinctions are often linked with the combined effects of CO2 and S emissions (by mantle plumes) Smoking gun: current levels of atmospheric CO2 (more than 400 ppm), which is much larger than range of fluctuations over the last 800,000 years. Current situation is not about making predictions, but increasing verification that predictions made 20 years ago are happening (do a search for extreme weather events in 2023) 2023 already declared hottest year on record (see slide 30 plotting increase mean temperatures) Not material for exam but keep an eye on COP28. Things are changing, no time to lose hope. Earthquakes and Tsunamis As most volcanoes: linked to plate boundaries (but some are not!) Risk areas essentially follow subduction and collision boundaries. Page 8 of 11  Best understood in the context of “elastic rebound theory” (energy accumulates and is released periodically when to block move against each other along a fault) Epicenter (projection to surface), hypocenter (focus), magnitude (amount of energy) are directly related to the “rupture area” (the area of the fault that breaks; everything remains attached, although other events – aftershocks – help movement of block and release of energy) Three types of seismic waves: o P waves – primary, fastest, not as destructive o S waves – secondary (also shear), the one used to figure out outer core is liquid o Surface waves – slowest BUT most destructive: § Two types, meaning the ground moves up and down AND sideways when they arrive. Three types of scale, two for energy, one to manage response. o Moment magnitude replaced the Richter scale long ago (it is more accurate for energy released) o Mercalli scale is subjective (estimate of structural damage) o Know the difference between each unit in the moment magnitude scale (a factor of 32, meaning an earthquake of magnitude 9 is 32x32 ~ 1000 times stronger that a magnitude 7 and a million times stronger than a magnitude 5) Earthquakes are located using the difference in arrival time of P and S waves, which indicates distance. “Triangulation” is the method of using several locations and the estimated distance to the earthquake (intersections of circles with the estimated distance from each location) Tsunamis are produced by displacement of large volumes of water during earthquakes (hence, much different that surface movement of waves by air) o Normal waves do not move mass of water, tsunami waves do. o On open water: wave amplitude is long (height is low, roughly 1 m) o As water get shallower: wave amplitude is smaller, volume of water increases) o Narrow bays funnel water and result in highest tsunami waves o Best understood not as tall waves but sea water flooding with very strong undercurrents (when they arrive and when they retreat). o Often more than one tsunami wave (much in the same way ripples on a lake are “trains” roughly equally spaced) o First “arrival” may cause sea retreat instead of flood (but flood will come). Why is it so difficult to predict earthquakes? Areas of risk are easy to identify, but when material will fail is not. In general, it is better to have many small earthquakes (energy is dissipated continuously) than long periods of deformation without earthquakes (means energy is being accumulated). The Interior of the Earth: Reflection and refraction principles: foundation to estimate variable thickness of the crust, layering in the mantle, diameter, and composition (solid, liquid) of the core. Seismic waves are more complex than P, S, because of reflectors (but there will be no questions asking for things like PKIKP!) Energy Resources Two types: renewable (wind, solar, tides, hydroelectric) and non-renewable (fossil fuels, uranium) Dependance of fossil fuels is still very strong (~ 80% of total energy production) Page 9 of 11  Presenting information only as percentage of energy production disguises the fact that total energy consumption/production has been increasing year over year. Consumption per country AND consumption per capita need to be considered (each one by itself is insufficient) Fossil fuels can be thought as “natural batteries” based on two processes: o Photosynthesis used solar energy to make plant tissue from CO2 and water. o Burial of organic matter used internal heat (from natural radioactive decay, i.e., nuclear) to transform organic matter into oil, gas, coal (we did not see this in class, but burial removes H and O, making longer C-C connections) o Burning fossil fuels liberates the combined solar and nuclear energy used to make fossil fuels from CO2 and water. o Great for human development, except that the rate at which we are reversing the process (burning of fossil fuels) is millions of times faster than the rate at which fossil fuels are produced by nature. Extraction of fluid fuels (gas, oil) from sedimentary rocks require porosity (open spaces) and permeability (connectivity of such spaces) o Some sandstones have better permeability (best reservoirs) but few (if any) of these are found these days (except deeper offshore) o Some shales (source rocks) have good porosity, but very low permeability. Require Meteoritic Impacts (added Dec. 07) Catastrophic geological processes. Risk of impact decreases rapidly with size: o Very small, but non-zero, probability of very large impacts o Impactors in the size range of the 2013 Chelyabinsk event (~ 20 m in diameter) are expected to occur about once every 50 years. Effect largely depends on size of impactor: o Larger than 1 km: global effect (from o 500 m to 1,000 m: continent-scale destruction o 200 m to 500 m: destruction at size of average country o 50 m to 200 m: destruction equivalent to large thermonuclear weapon (large city scale) o Less than 50 m: minor damage fireballs, shockwaves (Chelyabinsk-type) Sudbury Impact Structure 1.85 Ga: second largest known impact (impactor ~ 10 km in diameter): o Sudbury nickel mines are a in large part caused by this event (the meteorite did not add any metals but caused melting) o The two largest are old (Vredefort Dome is 2Ga) but the third largest known impact (Chicxulub, Mexico) is only 65 Ma (relatively young!) and caused the extinction of dinosaurs (and many other species) Several types of meteorites exist. They are useful to understand the origin and composition of the planet: o Iron meteorites: good evidence that the core is made of Fe and Ni (and likely some S) o Some chondrites: seem to represent the earliest material in the solar system (used to estimate the composition of the entire planet) Page 10 of 11 Mineral Resources (added Dec. 07) Except for wood, bone, leather (and perhaps a few other things). The materials used to advance civilization and drive technological advances need to be extracted from minerals and rocks. As we saw, most of the crust is made or about 8 to 9 elements. All the rest is present, but on average their concentrations are very small (parts per million to parts per billion; ppm or ppb respectively). Some geological process may produce concentration of elements of interest (or liberate them from the minerals that typically contain them). The Clarke Value (enrichment factor) is the typical grade divided by average abundance in the crust. It varies according to commodity (compare for example, Na, Cu, and Au in the slide deck) Sulfides are an important class of mineral because many metals of interest are found in them (Cu, Ni, Co, Pb, Zs, etc.). The main problem of mining sulfides is that, if not managed properly, intense chemical weathering of sulfides produces sulfuric acid (acid mine drainage). A fundamental message is that population increase and increase in living standards is only possible by continued extraction of the material resources needed. However, mineral extraction can be done responsibly (minimizing environmental impact). Final notes (value of earth sciences) One core aspect is mostly philosophical: our current understanding of “big time”, which is now based on astrophysics, started from geological observations. It is the framework from which many other disciplines could flourish (best examples are evolutionary biology and astronomy). More practical applications can be grouped into five categories: o Management, monitoring, and prevention of geological hazards (we saw earthquakes, and volcanoes, but flood, landslides, etc. are also important). Climate change can be considered a geological hazard (easily ignored because initial changes were not “dramatic”). o Finding and extracting energy resources (fossil fuel industry was traditionally one of the major industries in earth sciences). Uranium is another important source. o Finding and extracting mineral resources (from aggregates, such as sand, to all types of metals, to evaporites such as sodium chloride and lithium salts o Environmental monitoring and management of resources (to ensure minimal environmental impact during resource extraction, proper remediation afterwards, and monitoring; I should add a lecture on environmental aspects next year) o Understanding of processes at planetary scales (e.g., learning from past climate events to model and predict effects of CO2, methane, additions to the atmosphere. (Humans as a powerful force in the geological record – hence the Anthropocene) Hope you gain some valuable knowledge in this course that will serve you going forward. Regards, Pedro Page 11 of 11