Metamorphism and Types of Igneous Rocks.pptx

Earth Science

1. Metamorphism and Types of Igneous Rocks Earth & life science

2. After undergoing this learning material, you are expected to: 1. describe the changes in mineral components and texture of rocks due to changes in pressure and temperature (metamorphism) ( S11/12ES-Ic-17 ); and 2. compare and contrast the formation of the different types of igneous rocks ( S11/12ES-Ic-18 ) Learning Objectives: 1. identify the factors affecting metamorphism 2. classify metamorphic rocks in terms of metamorphic grade and foliation 3. make use of a graphic organizer that will compare and contrast the formation of the different types of igneous rocks 4. analyze igneous rocks in connection with composition and texture

3. Activity 1: Concept Map Directions: Understand and identify the processes of the Rock Cycle. Choose your answers from the box. ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ ____________________________________ Melting Weathering Lithification Heat and Pressure Cooling Melting Heat and Pressure Weathering Weathering

4. Factors that Affect Metamorphism: 1. TEMPERATURE During the burial of rocks (collision or subduction), as it goes deeper the temperature increases. Thus, higher temperature is expected during this process. 2. PRESSURE There are two types of stress due to the increase of pressure, uniform stress , and differential stress . Uniform stress is also called hydrostatic stress or confining stress because the pressure is equal from all directions while in differential stress the pressure from all directions are not equal. 3. FLUID PHASE Spaces between mineral grains in rocks may contain dissolved ions of H2O that speeds up chemical change of a solid mineral into a new solid mineral. This alteration process is known as metasomatism . 4. TIME Metamorphism is a slow process and grains (mineral size and shape) increases with time. Coarse grain metamorphic rocks took longer time of metamorphism.

5. Types of Igneous Rock Formation Igneous rocks can be classified into types according to its formation. Extrusive igneous rocks also known as Volcanic igneous rocks solidify at the surface. Intrusive igneous rocks otherwise called Plutonic igneous rocks crystalizes at depth. Igneous rocks are characterized in terms of texture (size, shape, and arrangement) and composition (chemical makeup). The size of grain is relative to the rate of cooling. Thus, slow rate of cooling will produce large crystals intrusively while rapid rate of cooling will result small crystals extrusively .

6. Metamorphic Grade Metamorphic Grade is the relative temperature and pressure conditions necessary for the formation of metamorphic rocks. 1. Low-grade metamorphism – abundant in hydrous minerals at temperatures ranging from 200 to 320 ºC and a relatively low pressure. Examples are Clay Minerals, Serpentine, and Chlorite. 2. High-grade metamorphism – non-hydrous minerals at temperatures exceeding from 320 ºC and a relatively high pressure. Examples are Biotite, Pyroxene, and Garnet. There are two types of metamorphic rocks : foliated and non-foliated . Examples of foliated metamorphic rock are Slate, Schist, and Gneiss while Amphibolite, Quartzite and Marble are examples of non-foliated metamorphic rock because there is no evident planar formation.