Igneous, Sedimentary & Metamorphic Rocks ...and the Rock Cycle PowerPoint Notes created by S. Koziol Date : 9/7/2013 Revised : ?/?/??
Compare and contrast intrusive and extrusive igneous rocks. Describe the composition of magma Discuss the factors that affect how rocks melt and crystallize. Igneous Rocks • Classify different types and textures of igneous rocks. • Recognize the effects of cooling rates on grain sizes of igneous rocks. • Describe some uses of igneous rocks.
Igneous - crystallization Igneous rocks are formed when magma crystallizes.
Lava Lava is magma that flows out onto Earth's surface.
Melting Point Factors that affect a rock’s melting point include pressure and water content.
Melting Point - continued As the water content of rock increases, the melting point decreases.
Intrusive Igneous rocks that cool slowly beneath Earth’s crust are intrusive.
Grain-size Extrusive rocks, which cool more rapidly than intrusive rocks, are generally more finely grained.
Coarse-Grained Intrusive igneous rocks form coarse-grained rocks. Diorite is a coarse-grained, intrusive igneous rock that is intermediate in composition between granite and gabbro.
Extrusive Igneous rocks that cool quickly on Earth’s surface are extrusive. Obsidian is an igneous rock that forms when molten rock material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure. Aka volcanic glass
Igneous Classification Extrusive igneous rocks Intrusive igneous rocks Both terms describe an igneous rock which is classified based on how it is formed. Coarse-grained igneous rocks that cool slowly beneath Earth’s surface are intrusive igneous rocks. Fine-grained rocks that cool quickly on Earth’s surface are extrusive igneous rocks.
Composition Classification Igneous rocks are classified as felsic, mafic, and intermediate.
Main 3 Intermediate rocks lie between felsic and mafic rocks in silica and iron content. Felsic rocks are light-colored, have high silica content, and contain quartz and feldspars. Mafic rocks are dark-colored, have low silica content, and are rich in iron and magnesium.
Porphyritic texture A rock that has grains of two different sizes has porphyritic texture.
Felsic Felsic rock is light-colored rock such as granite that has high silica content. Half Dome at Yosemite National Park is composed of granodiorite
Mafic Mafic rock is dark-colored rock such as gabbro that is rich in iron and magnesium.
Ultramafic Ultramafic rock is rock that is very high in iron and magnesium. Ultramafic pillow-lavas (YOUTUBE Link)
Bowen’s A model that illustrates the predictable patterns of mineral formation from cooling magma is Bowen's reaction series.
Ores & Gems Valuable ore deposits and gem crystals are often associated with igneous intrusions.
Kimberlites Kimberlite is course-grained rocks associated with diamonds in igneous outcrops, named after the area of S. Africa where they were first discovered.
Sedimentary Rocks • Sequence the Formation of Sedimentary Rocks. • Explain the formation and classification of clastic sediments. • Describe features of Sedimentary Rocks. • Describethe types of clastic Sedimentary Rocks. • Explainhow chemical sedimentary rocks form. • Describeorganic Sedimentary Rocks. • Recognizethe importance of Sedimentary Rocks.
Sediments Much of Earth’s surface is covered not by solid rock, but by sediments. Actual outcrops are a rare feature.
Sediments (continued) Sediments are pieces of solid Material deposited on Earth’s surface.
Deposition Deposition is the process of sediments being laid down on the ground or sinking to the bottom of water.
Lithification Lithification is the physical and chemical processes that compact and transform sediments into sedimentary rocks.
Permineralization During lithification, parts of an organism are replaced by minerals and turned into rock.
Erosion Landslides, moving water, wind, and glaciers cause erosion of surface materials.
Sorted Deposits Sorted deposits are characteristic of sediments transported by water and wind.
Weathering Effects Weathering of rock produces worn surfaces and rounded corners that are characteristic of some clastic sediment particles.
Clastic Sediments Clastic sediment particles have worn surfaces and rounded corners.
Breccia Breccia sedimentary rock is coarse-grained with angular fragments.
Bedding The primary feature of sedimentary rocks is horizontal layering called bedding. (repetitive laying)
Graded Bedding Graded bedding has the heaviest and coarsest material is on the bottom.
Graded Bedding (continued) Graded bedding is produce in marine landslides.
Unsorted Bedding Landslide and glaciers produce unsorted deposition.
Cross bedding Cross bedding is inclined sediment layers that migrate forward across a horizontal surface.
Ripple Marks One-way wave actions of wind or water produce asymmetrical ripple marks.
Dry Land Evidence The presence of dry land in past environments allow for the deposition of four-footed animal fossils.
Porosity Porosity is the percentage of open spaces between grains in a rock.
Sandstone vs Shale Porosity Sandstone is porous. When its pore spaces are connected to one another, fluids can move through the sandstone, making sandstone layers valuable as underground reservoirs. However, shale has low porosity, meaning that the pore spaces are small. This hinders the movement of fluids.
Evaporite Evaporite are layers of chemical sedimentary rocks that form from precipitated minerals.
Compare & Contrast Both are sedimentary rocks which are classified by method of formation. Conglomerates form from deposits of loose sediments on Earth’s surface. Evaporites form when water evaporates from mineral-rich solutions, causing the minerals to precipitate out of the solutions.
Limestone Limestone is an organic sedimentary rock, and is the most abundant organic sedimentary rock on Earth. It is calcite-rich (CaCO3).
Weathering If weathering did not occur, sedimentary rock would not form. Its absence would likely affect the formation of igneous and metamorphic rock as well.
Ancient Conditions Some sedimentary rocks contain sedimentary structures that indicate the location and direction of flow of ancient rivers, the wave or wind direction over lakes and deserts, and ancient shoreline positions.
Section 3 Metamorphic Rocks & the Rock Cycle • Compare andcontrast the different types and causes of metamorphism. • Distinguishamong metamorphic textures. • Explain how mineral and compositional changes occur during regional metamorphism. • Understand how rocks change from one type to another in the rock cycle.
Contact Metamorphism Contact metamorphism results when rocks come in contact with molten rocks such as those in an igneous intrusion.
Metamorphic - Foliated Foliated metamorphic rocks are composed of minerals with crystals that have their long axes perpendicular to pressure.
Nonfoliated metamorphic Nonfoliated metamorphic rocks are composed of minerals that form blocky crystal shapes.