Warm Up 10/8 What type of sedimentary rock is formed from weathered particles of rocks and minerals? a intrusive sedimentary rock c clastic sedimentary rock b chemical sedimentary rock d biochemical sedimentary rock What type of rocks are formed by processes powered by the sun? a No rocks are formed by energy from the sun b sedimentary rocks c igneous rocks d metamorphic rocks What type of composition does an igneous rock have that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals? a ultramafic c basaltic b andesitic d granitic Answers: 1) c 2) b 3) b Metamorphic Rocks Chapter 3, Section Formation of Metamorphic Rocks     Most metamorphic changes occur at elevated temperatures and pressures These conditions are found a few kilometers below Earth’s surface and extend into the upper mantle Contact Metamorphism – hot magma moves into rocks and changes the rock around it Regional Metamorphism – occurs during mountain building as large areas of rock are subjected to temperature and pressure changes Regional metamorphism results in large-scale deformation and high-grade metamorphism Formation of Metamorphic Rocks Contact Metamorphism Regional Metamorphism Concept Check   Compare and contrast contact and regional metamorphism Both processes change existing rocks into metamorphic rocks Contact metamorphism is caused by magma and often produces slight changes in rocks Regional metamorphism is large-scale deformation that can result in drastic changes to the rocks involved Agents of Metamorphism      The agents of metamorphism are heat, pressure, temperature, and hydrothermal solutions The most important agent of metamorphism is heat and comes from two sources, magma and change of temperature with depth Minerals become unstable and recrystallize to form new minerals With increased heat and pressure deep in the crust, rocks will flow instead of fracture Hot fluids will dissolve old minerals and deposit new ones, changing the composition of the rock Agents of Metamorphism Stress as a Metamorphic Agent Classification of Metamorphic Rocks    The texture of metamorphic rocks can be foliated or nonfoliated Foliated Metamorphic Rocks – The realignment of the minerals, at right angles to the direction of force, produces a banded appearance Nonfoliated Metamorphic Rocks – metamorphic rocks that does not have a banded texture and contains only one mineral Classification of Metamorphic Rocks Foliated – Gneiss Nonfoliated – Marble Concept Check   Contrast foliated and nonfoliated metamorphic rocks Foliated metamorphic rocks have a layered or banded appearance Nonfoliated metamorphic rocks not have a banded texture Assignment    Read Chapter 3, Section (pg 80-84) Do Section 3.4 Assessment #1-8 (pg 84) Study for Chapter Quiz! [...]...Concept Check   Contrast foliated and nonfoliated metamorphic rocks Foliated metamorphic rocks have a layered or banded appearance Nonfoliated metamorphic rocks do not have a banded texture Assignment    Read Chapter 3, Section 4 (pg 80- 84) Do Section 3. 4 Assessment #1-8 (pg 84) Study for Chapter 3 Quiz!