Igneous+Rock+Identification+Lab
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School
Liberty University Online Academy *
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Course
211
Subject
Geology
Date
May 18, 2024
Type
Pages
4
Uploaded by disneygirl1995
IGNEOUS ROCK IDENTIFICATION LAB Name: Date: Objective To practice identifying igneous rocks based on color, mineral composition, and texture Materials • Igneous Rock Identification Table (in the lesson)
• 8 Igneous Rock Samples (Images in lesson)
Procedure 1.
Complete the Purpose
and Hypothesis
sections of your lab worksheet. 2.
Complete the data table for each rock sample by identifying the characteristics of the rock samples using the images in Canvas and the Igneous Rock Identification Table provided. See Steps 3–5 for how to utilize the Igneous Rock Identification Table. 3.
Observe the color of the rock sample. If the color is dark, it is considered mafic, and you will look on the mafic column to determine the possibilities that it could be. If the color is light, it is considered felsic
. If it is in between, look at the intermediate column. NOTE: Obsidian is covers all three columns because it is mostly made of quartz with a small number of dark minerals. Reddish colored rocks are considered dark.
4.
Decide whether it is intrusive or extrusive (volcanic). Ask yourself, “Am I able to see the interlocking
crystals in this rock?” If the answer is “No,” you will want to follow the extrusive (volcanic) row across. Also, determine other characteristics of the rock's texture. For example, if it contains holes, it is considered vesicular
. 5.
You will find the rock name where the color column and the texture row come together on the Igneous Rock Identification Table. 6.
Complete the Data Table 1 and answer the questions that follow. Save your work, and submit the completed lab worksheet in Canvas. Purpose (5 pts) Write a 1-2 sentence purpose statement for this lab. What questions are you trying to answer? What do you hope the outcome will be?
Hypothesis
(5 pts)
Write a hypothesis for what you think the outcome of this lab exercise will be. A hypothesis is always written as 1 sentence that is an if/then statement. (Continue to the next page.)
2
Data Table 1
(72 pts) Complete the data table for each sample to help you identify the rock correctly. Use the Igneous Rock Identification Table to help. (4 pts per Rock Name + 2 pts per blank = 72 pts total) Sample Number Rock Name Color (Felsic, Intermediate, Mafic) Texture (Intrusive, Extrusive/Volcanic) Intrusive Texture (Pegmatite, Phaneritic, N/A) Extrusive Texture (Aphanitic, Porphyritic, Glassy, Vesicular, Pyroclastic, N/A) 1 Intermediate N/A Aphanitic 2 Vesicular 3 4 Felsic Phaneritic N/A 5 Extrusive 6 Felsic, Intermediate, Mafic Glassy 7 Intrusive 8 Felsic
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Observations
(8 pts)
In the 8 rock samples that you observed, what is the main difference you notice between the extrusive (volcanic) and intrusive igneous rocks? Looking at the Igneous Rock Identification Table and your samples, what minerals make a rock felsic that are not present in mafic rocks? Write 2-4 sentences answering these questions. Analysis & Conclusion
(8 pts)
Why do you think the intrusive igneous rocks have larger crystals than the extrusive (volcanic) igneous rocks? Is there any additional information about the rock samples that would have helped you to identify the name of the igneous rocks? How could this lab exercise be improved? Did you have any difficulty identifying one or more of your rock samples? If so, which sample did you find challenging and what information did you use to help identify the rock name? Write 5-6 sentences answering these questions. Application
(2 pts)
If you were mining for the largest quartz crystals you could find, which rock on your Igneous Rock Identification Table would give you the best chance of finding large quartz crystals? Why? Please state your answer in complete sentences. 4