ERTH101 Lab 5 Part 1 of 2 - Activity 5

ERTH101 Lab 5 Part 1 of 2 - Activity 5.2 Investigating Mineral Grain Size in Igneous Rock

Question 1 of 6 2 Points

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1. Measure the size of at least 5 crystals in each of the two images and average the values. Report your answers in the statements below in mm. Give your number to the nearest tenths place (for example, 2.4).

             The crystals in the image on the left have an average size of              mm.

             The crystals in the image on the right have an average size of           mm.

Question 2 of 6 1 Points

2. Aphanitic texture is associated with rapid cooling

 True

 False

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Question 3 of 6 1 Points

B. Phaneritic texture is associated with slow cooling

 True

 False

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Question 4 of 6 1 Points

2. Fill in the blank with the most appropriate texture term (aphanitic or phaneritic) that correctly completes the following statement

Lavas most commonly have a(n)   texture.

https://laulima.hawaii.edu/portal/site/MAN.85372.202210/tool/2af0c7b5-efba-458e-a629-3574a6f1f5fe/jsf/delivery/beginTakingAssessment  1/3 9/17/21, 8:37 AM                 Laulima : ERTH-101L-007 [MAN.85372.FA21] : Tests & Quizzes

Question 5 of 6 2 Points

3. Fill in the blanks below with the term (slowly or rapidly) that correctly completes the following statements

The phenocrysts formed when the magma was cooling   .

The groundmass formed when the magma was cooling   .

Question 6 of 6 1 Points

C. Based on everything you've learned in this activity, the porphyritic texture in the rock in

Fig. A5.2.2 likely formed from cooling rates that were:

Part 2 of 2 - Activity 5.3 Glassy and Vesicular Textures of Igneous Rock