annotated-Lab%205%20Metamorphic%20Rocks

1 GEOL 3340 Lab 05 Metamorphic Rocks Observe and record the properties of the metamorphic rock samples displayed in the lab room and use them to identify the samples. Lists of properties can be found below, as well as links to rock identification keys. Please complete the attached worksheets and submit them to your instructor. Don’t forget to put your name on the worksheets! Important notice: In this lab you will be using hydrochloric acid (HCl). This is a dangerous liquid for skin and eyes, and it can also damage clothes. – By starting to work on this lab, you acknowledge that you have read and understood the dangers associated with the use of HCl. If you don’t want to use it, ask your lab instructor to use it for you. Acknowledgement: Thank you to Dr. Cornelia Winguth for preparing this exercise. Grain Size: • Gravel > 2 mm • Sand 0.06-2 mm • Silt 0.004-0.06 mm • Clay < 0.004 mm Foliation: • Foliated • Non-foliated Composition: • Can you identify any minerals in the rock? Other Observations: • Color • Banding • Cleavage • … Identification Keys and Information About Rocks: http://geology.about.com/od/rocks/a/Rock-Tables.htm http://facweb.bhc.edu/academics/science/harwoodr/Geol101/labs/metamorf/ http://jersey.uoregon.edu/~mstrick/MinRockID/RockID/MetaClass.html http://en.wikipedia.org/wiki/Metamorphism Text: Pages 201-206

2 Name: Alberto Canales ___ Examining and Classifying Metamorphic Rocks Sample Number Foliation Grain Size Composition Other Observations Rock Name 1 No Gravel Calcite and/ or dolomite Reactive to acl, meaning parent rock is limestone Marble 2 No Mix of Silt and Gravel Hornblende and plagioclase Seemingly even black grains, but has bigger rocks scattered throughout Amphibolite 3 Yes Sand Mica, quartz, feldspar, amphiboles, garnet, pyroxene. Shiny visible grains Schist 4 No Gravel Quartz Sparkly, various grain sizes. Quartzite 5 Yes Clay Mica Seemingly solid black rock. Not visible grain Slate 6 No Mix of sand and Gravel One or more of the three magnesium silicate minerals (lizardite, chrysotile, antigorite) Dull green rock. Unevenly scattered grains. Serpentinite 7 Yes Mix Sand Mica, quartz, feldspar, amphiboles, garnet, pyroxene. Smaller visible grains with a few larger grains scattered evenly. Visible layers. Gneiss 8 yes Silt Mica, quartz, feldspar, amphiboles, garnet Perfect layered with barely visible grains Phyllite

4 Metamorphic Rock Formation 1) What are the likely parent rocks of the rocks that you identified in the first part of the lab? 2) What is their approximate metamorphic grade? 3) What are the likely types of metamorphism that the rocks experienced? Sample #/Rock Name Parent Rock and Metamorphic Grade Marble Parent Rock: Limestone Grade: low but variable Amphibolite Parent Rock: Basalt Grade: Intermediate Schist Parent Rock: Slate or phyllite Grade: Intermediate/ high Quartzite Parent Rock: Sandstone Grade: Variable Slate Parent Rock: Shale Grade: Low Serpentinite Parent Rock: Meta Igneous Grade: Low Gneiss Parent Rock: Granite or schist Grade: High Phyllite Parent Rock: Slate Grade: Low/Intermediate How do you identify a rock in the field to see whether they are igneous, sedimentary, or metamorphic? Igneous rocks have a glassy or crystalline texture, and they are formed from magma or lava cooling and solidifying. Sedimentary rocks are created by weathering, and they can have a clastic texture with fragments or a crystalline texture. Metamorphic rocks are made from existing rocks that are subjected to heat, pressure, and other chemical processes. They can have a foliated texture, such as slate or gneiss, or a non-foliated texture, such as quartzite or marble.