Types of Rocks PDF

 Directions: To come up with the correct answer for each number, unscramble the letter by placing the correct sequence in the shaded box. Use number boxes to complete the answer to the riddle. PETROLOGY  It is the scientific study of rocks. Rocks are combined aggregat...

 Directions: To come up with the correct answer for each number, unscramble the letter by placing the correct sequence in the shaded box. Use number boxes to complete the answer to the riddle. PETROLOGY  It is the scientific study of rocks. Rocks are combined aggregation of minerals.  Petrologist classified rocks based on how they were formed. In general, rocks are classified as igneous, sedimentary, and metamorphic rock.  A rock is a naturally occurring solid mixture of one or more minerals, or organic matter  Rocks are classified by how they are formed, their composition, and texture  Rocks change over time through the rock cycle  The Rock Cycle The rock cycle shows how one type of rocky material gets transformed into another – Representation of how rocks are formed, broken down, and processed in response to changing conditions – Processes may involve interactions of geosphere with hydrosphere, atmosphere and/or biosphere – Arrows indicate possible process paths within the cycle 1. How are igneous rocks transformed and become a sedimentary rock? 1. How are igneous rocks transformed and become a sedimentary rock? When igneous rock undergo weathering and carries by different agents then undergo deposition, compaction and cementation 2. What are the processes involved in the transformation of igneous rocks to sedimentary rocks? 2. What are the processes involved in the transformation of igneous rocks to sedimentary rocks? Weathering, deposition, compaction and cementation 3. How are sedimentary rocks transformed into metamorphic rocks? What are the processes involved in the transformation? 3. How are sedimentary rocks transformed into metamorphic rocks? What are the processes involved in the transformation? Through natural process sedimentary rocks undergo process of continues heating and pressure these rocks are transformed into metamorphic rocks 4. How are metamorphic rocks transformed into igneous rocks? What are the processes involve in the transformation? 4. How are metamorphic rocks transformed into igneous rocks? What are the processes involve in the transformation? Metamorphic rocks undergo process of cooling and crystallization  The Rock Cycle Magma is created by melting of rock above a subduction zone Less dense magma rises and cools to form igneous rock Igneous rock exposed at surface gets weathered into sediment Sediments transported to low areas, Convergent plate boundary buried and hardened into sedimentary rock Sedimentary rock heated and squeezed at depth to form metamorphic rock Metamorphic rock may heat up and melt at depth to form magma  Igneous rock forms when magma cools and solidifies  Magma can form: ▪ When rock is heated ▪ When pressure is released ▪ When rock changes composition  Derived from the latin word “ignis” meaning fire. http://www.fi.edu/fellows/payton/rocks/create/igneous.htm  Igneous Rock Identification Igneous rock names are based on texture (grain size) and mineralogic composition Textural classification – Plutonic rocks are coarse-grained and cooled slowly at depth – Volcanic rocks are typically fine-grained and cooled rapidly at the Earth’s surface Compositional classification – Mafic rocks contain abundant dark-colored ferromagnesian minerals rich in Ca, Fe, Mg – Felsic rocks contain abundant light-colored minerals rich in Al, K, Si, Na  Coarse-Grained Fine-Grained Felsic Granite Rhyolite Mafic Gabbro Basalt  Intrusive Igneous Rocks: magma pushes into surrounding rock below the Earth’s surface. Ex. granite  Extrusive Rocks: forms when magma erupts onto the Earth’s surface (lava), cools quickly with very small or no crystals formed. Ex. basalt http://www.windows.ucar.edu/tour/link=/earth/geology/ig_intrusive.html&edu=high&fr=t Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form. Is this rock Felsic or Mafic? Is it fine-grained or coarse-grained? Is this rock Intrusive or Extrusive? Mafic, fine grained, extrusive  Sedimentary rock is formed by weathering and erosion  Sediments are moved from one place to another  Sediments are deposited in layers, with the older ones on the bottom  The layers become compacted and cemented together http://www.fi.edu/fellows/payton/rocks/create/sediment.htm  Sedimentary Rocks are formed at or near the Earth’s surface  No heat and pressure involved  Strata – layers of rock  Stratification – the process in which sedimentary rocks are arranged in layers  Clastic – made of fragments of rock cemented together with calcite or quartz Breccia is a term most often used for clastic sedimentary rocks that are composed of large angular fragments (over two millimeters in diameter). The spaces between the large angular fragments can be filled with a matrix of smaller particles or a mineral cement that binds the rock together.  Chemical sedimentary – minerals crystallize out of solution to become rock Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters. It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris.  Organic sedimentary – remains of plants and animals Coal is an organic sedimentary rock that forms from the accumulation and preservation of plant materials, usually in a swamp environment. Coal is a combustible rock and along with oil and natural gas it is one of the three most important fossil fuels.  Meaning to change shape  Changes with temperature and pressure, but remains solid  Usually takes place deep in the Earth http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm   Contact Metamorphism – heated by nearby magma  Increased temperature changes the composition of the rock, minerals are changed into new minerals Hornfels is a fine-grained non-foliated metamorphic rock produced by contact metamorphism http://www.windows.ucar.edu/tour/link=/earth/geology/meta_contact.html&edu=h igh&fr=t   Regional Metamorphism – pressure builds up in rocks that is deep within the Earth  Large pieces of the Earth’s crust collide and the rock is deformed and chemically changed by heat and pressure http://www.windows.ucar.edu/tour/link=/earth/geology/meta_regional.html&edu=high&fr=t   Foliated - contain aligned grains of flat minerals Gneiss is foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains. It typically contains abundant quartz or feldspar minerals.  Non-Foliated – mineral grains are not arranged in plains or bands Marble is a non- foliated metamorphic rock that is produced from the metamorphism of limestone. It is composed primarily of calcium carbonate.  Determine if the following rock samples are foliated or non-foliated: Amphibolite Quartzite Phyllite Non-foliated Non-foliated Foliated