Sp21_Lab10_student

GEOL 101L Lab 10: Categorizing rocks Name: Poojha Palle Date: 4/27/2021 Introduction Today, we’re going to review rock types and practice categorizing rocks using observable characteristics. You may see some rocks that you did not see previously! The learning objectives for today are: Students will be able to….  Make observation about rocks samples that provide relevant information for categorizing rocks.  Categorize rocks as igneous extrusive, igneous intrusive, chemical sedimentary, clastic sedimentary, foliated metamorphic or non-foliated metamorphic based on observable physical characteristics  Differentiate between these 6 rock categories based on method of rock formation  Identify igneous, metamorphic, and sedimentary rocks by using flow charts of rock characteristics Materials:  Access to Sakai, Zoom, and other websites  Editable copy of the lab (hard copy, .pdf or .docx file)  Images and hyperlinks of rocks to observe. Part A: Observing Rocks How to do this part:  (~15 minutes) You will be assigned a letter: your TA will review Samples 1-2, Student A (samples 3-4), B (5-6), C (7-8), D (9-10), E (11-12). You will make detailed observations of your assigned rock samples.  (~20 minutes) Work with other students in Zoom break-out rooms to share and summarize observations. Geologists start the process of identifying rocks by making detailed observations of the rocks. Detailed images of 12 different rocks are available at the links below. 1. Make detailed observations (be as detailed and quantitative as possible!) You only need to do this for the 2-3 rocks you’ve been assigned (based on the letter you were assigned). Feel free to work on other samples if you finish yours before the time is up. 2. When placed into break-out rooms, work with your team to fill out the rest of the chart. (Table is on the next page) 1

GEOL 101L Lab 10: Categorizing rocks Name: Poojha Palle Date: 4/27/2021 Table 1. Detailed descriptions of rock samples (continues onto next page) Use the “Table 1 rocks” document for rock samples (hyperlinked to web images in case you want to zoom in) Grain size – coarse, fine, both Color – homogenous implies 1 dominant mineral Foliation/banding – implies rock is metamorphic Any notable/easily recognizable properties – diagnostic tests (hardness, acid reaction, etc) Sample # Assigned student Detailed descriptions including information relevant to ID 1 TA Grain size is coarse with large minerals (grain > 5 mm) Color is varying (both light and dark minerals) White minerals are smaller and glassier Dark minerals are platy/tabular No foliations 2 TA Grain size is coarse (smaller in size, though) Color is dominantly green with white minerals throughout No foliations Harder than 5.5 and does not react to HCl 3 A Fine grained, a light/pale tan color with no foliation. 4 A Coarse grained, grey colored with hints of yellow, non-acidic, non-foliated, and harder than glass (>5.5) 5 B Grain size is fine, color is dominantly yellow with red undertones; has no foliations. Hardness is greater than 5.5 and does not react with acid. 6 B Grain size is coarse, color is a mix of tan and dark colored platy minerals. There are foliations but minerals look slightly angular. Does not react to acid and hardness is greater than 5.5. 7 C Coarse grained, light beige color, acidic, non-foliated, not harder than glass (<5.5) 8 C Coarse grained, dark-colored with flecks of white, non-foliated 9 D Fine grained, mostly 1 white mineral, reacts to acid, hardness is <5.5 10 D Fine grained, transparent, doesn’t react to acid, hardness is <5.5 11 E Coarse grained, more than 1 mineral, non-foliated, harderness >5.5 12 E fine grained, gray color 2

GEOL 101L Lab 10: Categorizing rocks Name: Poojha Palle Date: 4/27/2021 Part B: Categorizing rocks using geologist-determined characteristics How to do this part:  (~25 minutes) Organize the rocks into 3 groups based on shared characteristics. Base your groupings on the following characteristics: The size, shape and/or alignment of the crystals or grains that make up the rock, and the minerals present (you can determine with reactions with acid, hardness, etc).  Use the appendix, “Links to high-resolution images and diagnostic tests for each rock sample,” to help. Characteristics you may want to look at for categorization include:  Grain size: are the constituent minerals the same sizes or are there distinct size populations? Can you see the individual grains without a hand lens?  Grain shape: what are the shapes of the constituent grains (equant? plates? spherical?). Do the grains have rounded or sharp edges? Are crystals or clasts visible?  Texture: how are the grains arranged with respect to one another? Do they form planes in the rock? Are the grains interlocking or do voids separate the grains?  Mineral or Rock Constituents: are the grains minerals or rock fragments? Are they dark or light colored? What are the proportions of dark and light minerals? Do the grains fracture or cleave? Do any of the grains ‘fizz’ when dilute acid is dropped on them? Can any of the constituents be scratched with a knife? Are any of the constituents magnetic? 3. Working with your group members, the detailed descriptions you generated in Part A, and thinking in terms of the geologist-defined characteristics, organize the rock samples into sedimentary, igneous, and metamorphic groups. There are 4 rocks from each group. Sedimentary : Samples 5, 7, 11, 10 Metamorphic : Samples 6, 2, 4, 9 Igneous : Samples 1, 3, 8, 12 4

GEOL 101L Lab 10: Categorizing rocks Name: Poojha Palle Date: 4/27/2021 Part C: Matching geologist-defined categories with rock samples  (~20 minutes) Read the brief descriptions of the geologist-defined rock categories. Look at how geologist would have grouped the rocks you saw. Match each pair of rocks to the appropriate geologist-defined category.  (~15 minutes) Answer the questions and write reflection Geologists would classify these 12 rocks into 6 groups: extrusive igneous, intrusive igneous, foliated metamorphic, non-foliated metamorphic, clastic sedimentary and chemical sedimentary. Read about them in the table in Appendix 2. 4. These are the groupings according to these classifications. Observe the samples again and match each grouping with one of the rock groups listed on the right. a. Samples 1 & 8 A. Extrusive igneous b. Samples 2 & 9 B. Intrusive igneous c. Samples 3 & 12 C. Foliated metamorphic d. Samples 4 & 6 D. Non-foliated metamorphic e. Samples 5 & 11 E. Clastic sedimentary f. Sample 7 & 10 F. Chemical sedimentary **When you are done, call your TA to your break-out room for the answers** Then, move on to Part D. Part D: Matching geologist-defined categories with rock samples, and reflection  (~15 minutes) Identify each rock from the choices given using ID charts from previous labs. 5. Sample 1 is: a. Granite b. Gabbro c. Diorite d. Andesite 6. Sample 2 is: a. Marble b. Hornfels c. Quartzite d. Phyllite 7. Sample 3 is: a. Basalt b. Obsidian c. Pumice d. Rhyolite 8. Sample 4 is: a. Slate b. Phyllite c. Schist d. Gneiss 9. Sample 5 is: a. Shale b. Sandstone c. Conglomerate d. Breccia 10. Sample 6 is: a. Slate b. Phyllite c. Schist d. Gneiss 5

GEOL 101L Lab 10: Categorizing rocks Name: Poojha Palle Date: 4/27/2021 Appendix 1. Links to high-resolution images and diagnostic tests for each rock sample Image: Sample 1 (A15) Image: Sample 2 (A01) Diagnostic tests: Sample 1 Diagnostic tests: Sample 2 ----------------------------------------------------------------------------------------------------------------------------------------- Image: Sample 3 (A02) Image: Sample 4 (A06) Diagnostic tests: Sample 3 Diagnostic tests: Sample 4 ----------------------------------------------------------------------------------------------------------------------------------------- Image: Sample 5 (A09) Image: Sample 6 (A03) Diagnostic tests: Sample 5 Diagnostic tests: Sample 6 ----------------------------------------------------------------------------------------------------------------------------------------- 7

GEOL 101L Lab 10: Categorizing rocks Name: Poojha Palle Date: 4/27/2021 Image: Sample 7 (A02) Image: Sample 8 (A10) Diagnostic tests: Sample 7 Diagnostic tests: Sample 8 ----------------------------------------------------------------------------------------------------------------------------------------- Image: Sample 9 (A04) Image: Sample 10 (A20) Diagnostic tests: Sample 9 Diagnostic tests: Sample 10 ----------------------------------------------------------------------------------------------------------------------------------------- Image: Sample 11 (A01) Image: Sample 12 (A05) Diagnostic tests: Sample 11 Diagnostic tests: Sample 12 ----------------------------------------------------------------------------------------------------------------------------------------- 8