330 likes | 339 Views
Discover the interrelations between igneous, sedimentary, and metamorphic rocks. Learn about the formation processes and composition of each rock type, from magma to metamorphism. Explore the impact of weathering, erosion, and deposition on shaping our planet's surface. Delve into rocks' transformation journey and uncover the wonders hidden within the Earth's crust.
E N D
Chapter3 Rocks
Fascinating Fact Digging at a rate of one foot per minute, it would take you 87 years to tunnel all the way through Earth. Rock Cycle
Rocks 3.1 The Rock Cycle Rocks are any solid mass of mineral or mineral-like matter occurring naturally as part of our planet.
Rocks 3.1 The Rock Cycle Types of Rocks Igneous 2. Sedimentary 3. Metamorphic
The Rock Cycle 3.1 The Rock Cycle Shows the interrelationships among the three rock types • Magma is molten material that forms deep beneath the Earth’s surface. • Lava is magma that reaches the surface
Weathering is a process in which rocks are physically and chemically broken down by water, air, and living things • Sediment is weathered pieces of Earth materials.
Formation of Igneous Rocks 3.2 Igneous Rocks 1. Intrusive igneous rocks are formed when magma hardens beneath Earth’s surface. Ex: Granite, Diorite 2. Extrusive igneous rocks are formed when lava hardens. Ex: Obsidian, Pumice
• Classification of Igneous Rocks 3.2 Igneous Rocks Igneous rocks can be classified based on their composition and texture. 1. Texture • Coarse • Fine- • Glassy texture
Classification of Igneous Rocks 3.2 Igneous Rocks 2. Composition • Granitic composition rocks are made mostly of light-colored quartz and feldspar.
Classification of Igneous Rocks 3.2 Igneous Rocks 2. Composition (continued) • Basaltic composition rocks are made mostly of dark-colored silicate minerals and plagioclase feldspar. • Andesitic composition rocks are between granitic light-color minerals and basaltic composition dark-colored minerals. • Ultramafic composition rocks are made mostly from iron and magnesium-rich minerals.
Formation of Sedimentary Rocks 3.3 Sedimentary Rocks Weathering, Erosion, and Deposition • 1. Erosion involves the weathering and the removal of rock. • 2. Deposition occurs when an agent of erosion—water, wind, ice, or gravity—loses energy and drops sediments.
Formation of Sedimentary Rocks 3.3 Sedimentary Rocks Compaction and Cementation • 3. Compaction is a process that squeezes, or compacts, sediments. • 4. Cementation takes place when dissolved minerals are deposited in the tiny spaces among the sediments.
Fascinating Fact Seventy percent of all the rocks on earth are sedimentary rocks.
Classification of Sedimentary Rocks 3.3 Sedimentary Rocks Two Main Groups 1. Clastic sedimentary rocks are composed of weathered bits of rocks and minerals. • Classified by particle size • Common rocks include - Shale (most abundant) - Sandstone - Conglomerate
Classification of Sedimentary Rocks 3.3 Sedimentary Rocks Two Main Groups 2. Chemical sedimentary rocks form when dissolved substances precipitate, or separate, from water. • Common rocks include - limestone—most abundant chemical rock - microcrystalline quartz known as chert, flint, jasper, or agate - evaporitessuch as rock salt or gypsum - coal
Formation of Metamorphic Rocks 3.4 Metamorphic Rocks Metamorphism means “to change form.” Most metamorphic changes occur at elevated temperatures and pressures. Conditions for formation are found a few kilometers below the Earth’s surface and extend into the upper mantle.
Agents of Metamorphism 3.4 Metamorphic Rocks 1. Heat • Provides the energy needed to drive chemical reactions 2. Pressure • Causes a more compact rock with greater density
Agents of Metamorphism 3.4 Metamorphic Rocks 3. Hydrothermal Solutions • Hot water-based solutions escaping from the mass of magma • Promote recrystallization by dissolving original minerals and then depositing new ones
Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks. How do sedimentary and igneous rocks change? The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change. If you exam metamorphic rock samples closely, you'll discover how flattened some of the grains in the rock are.