EESA06 Final Exam Study Guide.pdf

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Environmental Science
Lisa Tutty

EESA06 Final Exam Study Guide (With Pictures!) Tectonic Plates At MOR, there are only shallow earthquakes, at trenches, there are deep earthquakes. Geologic Time • Found By • Measuring the accumulation of the oceans salt content over time. • Measuring the time it took molten to cool to the present temperature of the earth • Scientist learned that earth is not young by evidence from • Tree rings • Ice cores- ice sample that contains years of ice history • Varves- layers of sediments, light and dark that change according to seasons • Rate of plate movement • Oldest rock on earth is said to be about 3.5 billion years old. • How we found the age of the earth: Early ideas of stratigraphy, fossils, relative age of rocks, absolute age, the geologic timescale • Key Steps in Earth’s Evolution: • Hadeon eon (4560 to 4400 million years ago): formation of earth from impacts, formation of earth’s core (iron catastrophe), large mars-sized impact rips out moon • Archeon eon (4400 to 2500 million years ago): first continental crust, basteria by 3800 million years ago • Proterozoic eon (2500 to 545 million years ago): rise in atmospheric oxygen~1800 million years ago due to photosynthesis, eukaryotes by 1600 million years ago • Phanerozoic eon (545 million years ago): Cambrian explosion (hard parts), subdivision based on fossil records, at least 5 major mass extinction events • Paleozoic (545 to 250 million years ago): life conquers land (plants, lungs, reptile eggs) • Mesozoic (250 to 65 milllion years ago): time of dinosaurs bipedal movements, birds, first mammals Cenozoic Era (65 million years ago to today): time of mammals and flowering • plants Radioactive dating of the Earth • "daughter" products form from "parents" at characteristic rates of decay (half-lives) •ratio of daughter products to remaining parent material tells how much time has elapsed •present estimate: 4.56 billion years old Geologic Resources • Canada consists of 4 layers, Layer 1 - Shield more than a billion years old • has metamorphic rocks caused by plate collisions and mountains, • craton makes up layer 1, shield is the eroded surface, oldest continental crust are high grade metamorphic rocks (gneiss), brought together by collision, some igneous rocks, the contients are welded by volcanos so therefore there are volcanic and plutonic rocks (welds together the parts of the craton) • Big producers are Volanogenic massive sulphides, banded iron formations, nickel Layer 2 about 400-600ma • had lots of mountains which was being eroded located near the equator, wore the mountain down processes called peneplanation, coral reefs started to develop, lots of limestone present and sedimentary rocks, the eroded material flows to the shallow water which can kill coral reef and produce clastic sedimentary rocks like shale stone, between layer one and two is the great unconformity, between layer 2 and 3 is the big gap • contains sedimentary rocks, forming in warm tropical seas, new mountains being built near the edge of the continent (east coast), apalation mountains, , basins were also forming which had room for sediments, sandstones and carbonates, surrounding the Hudson bay has layer 1 rocks • oil, gas, coal, salt (evaporite minerals such as Gypsum, Sodium Chloride and potasium chloride) Layer 3 less than 135 000 years old. • are not rocks they are sediments, famous in Ontario, glacial and interglacial (current) sediments. Sediments gathered after glaciation. • unconformity below it called the big gap, not lithified rocks it is sediments, great lakes were built by these ice sheets that cover Canada, the ice sheet melted and scraps the rock under it and left behind sediments, scraped rock basins out and left behind water, Niagara falls came after this glaciation episode, • quaternary sediments: placer minerals Layer 4 in TO, hundreds of years old. It consists of what we are doing to the planet, building roads gas stations etc • Mining processes:  Open-pit mine: shallow enough, blasted loose Underground Mine: deeper, blasted loose then carried by elevators and  trucks  Mill: place where ore is separated from the other rocks by crushing  Smelter or Leach Pads: roasted in furnace in a smelter or crushed and placed on pads with chemical or dissolving Evolution of Life on Earth Tie into tectonics • Hominoids were able to adapt to the constant changing environment by increasing brain size for thinking and managing environmental stresses and massive jaws for eating anything even meat • East Africa went fro
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