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Minerals, rocks, weathering, sequencing & energy. Std. 3. Minerals. Must have the following 5 characteristics: Naturally occurring Inorganic Solid Crystal structure Definite chemical composition. Identifying Minerals (physical properties). Color Streak Luster Density Hardness
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Minerals • Must have the following 5 characteristics: • Naturally occurring • Inorganic • Solid • Crystal structure • Definite chemical composition
Identifying Minerals (physical properties) • Color • Streak • Luster • Density • Hardness • Special Properties
Rock Cycle • Draw
igneous • Extrusive: • Surface • Cooled rapidly • Small crystals • Glassy • Intrusive • Inside earth • Cooled slowly • Larger crystal
sedimentary • Clastic • Rock fragments • Conglomerate & sandstone • Organic • Remains of plants & animals • Coal & limestone • Chemical • Minerals dissolved in solution crystalize • Limestone, halite (rock salt
metamorphic • Foliated • Grains in parallel bands • Gneiss, slate • Nonfoliated • No bands • Grains random
Weathering, erosion, deposition • Weathering • break rock down • Erosion • move it • Deposition • lay down sediment
EROSION • Water • Moves the most sediment • Glaciers • U-shaped valley, till, moraines, kettle lakes • Wind • Sand dunes • Gravity • Move sediment downhill
How fossils form • Death, soft parts decay, hard parts left (teeth, bones) • Sediment covers organism • Sediment becomes rock, preserving parts of organism
Types of fossils • Mold • Cast • Petrified • Cells replaced by minerals or sediment • Bones, petrified wood • Carbon films • Trace fossil • Original/preserved remains • Ice, tar, amber
Fossils & the past • Where do fossils form? • Most: Organisms that once lived in or near shallow water • Sedimentary rock • Tell us about past environments • Shallow bay, ocean bottom, freshwater swamp
Relative Age • Age comparison (older vs. younger) • Law of Superposition • Oldest layers at the bottom, youngest at the top
Determining Relative Age • Extrusion, Intrusion, Fault, Unconformity, Index fossil
Energy transfer • Volcanoes • Heat and mechanical energy as magma flows • Earthquakes • Energy transferred in seismic waves • Mechanical slipping of fault