Transcript ROCKS
ROCKS What is a rock? ►A mixture of minerals ► OR organic material There is a hierarchy to the Atoms make up elements. elements of Geology Elements combine to form the natural compounds. . Natural compounds and elements combine to form minerals. Minerals make up rocks. Rocks make up the Earth. IGNEOUS ROCKS Made from the cooling of molten rock ► Tough rock! ► Interlocking crystals ► ► Intrusive- cool from magma (underground); large crystals ► Extrusive- cool from lava (surface); small crystals ► HOW DOES COOLING RATE AFFECT crystal SIZE? IGNEOUS ENVIRONMENTS IGNEOUS CLASSIFICATION ► TEXTURES Coarse – big (can see with naked eye) crystals Fine – small crystals Vesicular- holes glassy ► COLOR- based on composition of magma/lava Mafic (basaltic)- dark- dense Felsic (granitic)- light-high in silicia less dense ► OBSIDIAN IS AN EXCEPTION► Dark color is from impurities ► Felsic rock (99% quartz) Lava flows in Michigan! Hawaii Igneous Rocks Rhyolite Granite Gabbro Basalt SEDIMENTARY ROCKS ► Made from sediments gritty ► Not tough (fragile) ► Forms fromCompaction- due to pressure (shale) Cementation- solution sticks grains together Evaporation- water evaporates leaves rock Precipitation- saturated solution (limestone) CLASSIFICATION OF SEDS ► TEXTURES Clastic (Detrial) - made of pieces ►gritty crystalline (Chemical)- from water ►Smooth; may see crystals Bioclastic - evidence of life Grand Canyon conglomerate coquina sandstone limestone coal METAMORPHIC ROCKS ► Igneous ► Forms ► Form or sed. rock that has changed from heat and/or pressure deep underground near the mantleBUT DO NOT MELT! Types of metamorphism ► Contact- existing rock comes in contact with hot magma Small scale Change from heat ► Regional- from tectonic plate collision Large scale Change from heat AND pressure CLASSIFICATION OF MET. ROCKS ► Foliated Flattening of minerals ► NON- foliated Not flattened, crystals get bigger Evidence of pressure foliation slate marble schist gneiss Mrs. Bouda’s favorite Rock! Igneous and Metamorphic rocks Sedimentary rocks Generalized Bedrock Geology of Michigan In Michigan, sedimentary rocks make up the bedrock in the eastern northern, and southern peninsulas.