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Rock Types November 21, 2011
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Todays Class Waiting for email on question for Gordon
Term 2: Grade Breakdown Test 1: 25% Test 2: 25% Term Paper: 25% Quizzes: 10% Participation 5% Test 3: 10% MC
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Rock Types A rock is a collection of one or more minerals. Rocks are divided into three major groups.
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Igneous Rocks rocks of molten origin
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Intrusive magma cooled at depth: often forced into cracks or cavities in a molten condition. Generally coarse-grained. eg granite, quartz, feldspar,
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Extrusive lava cooled on the surface after flowing out of cracks or volcanoes as lava. Generally fine-grained. eg pummice, obsidian
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SEDIMENTARY ROCKS are composed of the products of mechanical and chemical weathering. Sedimentary rocks are deposited usually in near-horizontal layers by the agents of transportation. eg wind, water, and ice. Burial produces lithification or hardening.
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Sedimentary Sources deserts - aeolian deposits glacial deposits
rivers - deltas shallow marine areas (fossils) deep marine areas reefs
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Types of Sedimentary Rocks
Conglomerate: composed of large rounded fragments embedded in a fine-grained material (easily eroded because made up of tiny particles and layers). b) Sandstone: composed mainly of sand-sized particles, and these are mainly of quartz.
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Sandstone
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Types of Sedimentary Rocks
Arkose: composed mainly of sand-sized particles of quartz and feldspar, the latter making up more than 25% of the total. d) Shale: composed of fine particles predominantly of clay size.
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Types of Sedimentary Rock
Limestone: composed of calcite either (1) chemically precipitated in water, or (2) accumulated through the collection of organic remains such as shells, or (3) the result of building up of organic rock through the action of organisms like corals
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METAMORPHIC ROCKS formed by the influence of heat and pressure on other rocks resulting in changes in mineralogy and texture
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Types of Metamorphic Gneiss: has a banded appearance with alternating composition; may be formed by metamorphism of an igneous or sedimentary rock b) Slate: fine-grained and platy; fissile; formed by the metamorphism of shale.
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Slate
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Types of Metamorphic Schist: rock flaky minerals (eg mica) aligned in a parallel fashion; formed by the metamorphism of shale and slate. d) Quartzite: hard, mainly composed of quartz; formed by the metamorphism of sandstone. e) Marble: a coarse, but even-grained rock formed by the metamorphism of limestone.
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Marble
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Rock Cycle
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