Plate Tectonics and Hot Spots_Online B

Name________________________________________ Section___________ Date________________________ Physical Geology Laboratory Plate Tectonics and Hot Spots Objectives: The student will: 1. examine the Emperor Seamounts and the Hawaiian Ridge, and the hot spot that created them. 2. discover the speed at which the Pacific Plate moved, and the change in direction that occurred. 3. devise how to write an overview paragraph. The map below is of the Emperor Seamounts and the Hawaiian Ridge system. The sides of the map are running North and South with North at the top of the map. West is to the left, and East is to the right. 1 Hazel Garza GEOL-1403-V09 9/20/23

All of the volcanic structures in the Emperor Seamounts and the Hawaiian Ridge system were created by one hot spot that is currently under the big island of Hawaii (lower right). The Pacific Plate has moved over the hot spot for more than 80 million years. Answer the Following Questions Where in the World? 1.) Determine the age of the following volcanic structures (Refer to Table 1 on Page 4). A.) __0 million years ___ is the age of the rocks at Hawaii (Kilauea). B.) _13 million years _____ is the age of the rocks at Brook Banks. C.) _43.400 million years _____ is the age of the rocks at Yuryaku Seamount. D.) _59.600 million years _______ is the age of the rocks at Suiko Seamount. E.) _82 million years _______ is the age of the rocks at Meiji Seamount at the northern end of the Emperor Seamounts. 2.) Locate the above volcanic structures on the map so that you see where the oldest volcanic structure is located, and so that you see where the youngest volcanic structure is located. Meiji Seamount is only shown on the smaller inset map. 3.) Hypothesis: _Southeast ______ is the general direction that the Pacific Plate has moved over the past 82 million years. (North, South, East, West, Northeast, Northwest, Southeast, or Southwest) Determining the Direction of Plate Motion 4.) Locate Yuryaku Seamount on the larger map. Locate Suiko Seamount on the larger map. We want to know the direction of plate motion between these two locations. (Do you know trigonometry? Never mind! LOL)! Actually, it is not that hard to obtain if you know the latitude and longitude of both locations. Volcanic Structure Latitude Longitude Bearing Angle Trend Yuryaku Seamount 32.670 172.270 -6.444 N 6.444 W Suiko Seamount 44.583333 170.333333 Go to the igis map web page for bearing angle. https://www.igismap.com/map-tool/bearing-angle And enter the Latitude and Longitude data into the Bearing Angle Calculator (just as it appears in the table). Be sure that you type the numbers in exactly. Once you have finished typing the latitudes and longitudes in, the calculator will show the Bearing Angle. Type your Bearing Angle into the table above. You might get a positive or negative number. Since we live in the Northern Hemisphere, our compasses point north, and the sides of the maps are parallel with True North. North is 0 degrees. A.) If your Bearing Angle is positive, then line between the two volcanic structure is trending East of North by those degrees. Example: N 30° E. This is how geologists write the trend of something. B.) If your Bearing Angle is negative, then line between the two volcanic structure is trending West of North by those degrees. Example: N 30° W. This is how geologists write the trend of something. 2

Determining the Average Rate of Plate Motion Table 1: In the following table, Km denotes Kilometers, MYrs. denotes Million Years, Cm denotes Centimeters, and Yr. denotes Year. The Rate of Plate Motion Km/MYrs, and the Rate of Plate Motion Cm/Yr. are both measured from Kilauea (Hawaii). Kilauea volcano is currently active, and the point that I measured everything else from. Volcanic Structure Km from Kilauea Age in MYrs. Rate of Plate Motion Km/MYrs. Rate of Plate Motion Cm/Yr. Kilauea 0 0.000 0 0 Haleakala 182 0.750 242.6 24.3 West Maui 221 1.320 167.4 16.7 East Molokai 256 1.760 145.4 14.5 Waianae 374 3.700 101.1 10.1 Unnamed A 913 9.200 99.2 9.9 La Perouse Pinnacles 1,209 12.000 100.7 10.1 Brooks Bank 1,256 13.000 96.6 9.7 Unnamed B 2,600 28.000 92.9 9.3 Unnamed C 2,825 27.400 103.1 10.3 Abbott 3,280 38.700 84.7 8.5 Yuryaku 3,520 43.400 81.1 8.1 Kimmei 3,668 39.900 91.9 9.2 Jingu 4,175 55.400 75.4 7.5 Suiko (southern) 4,794 59.600 80.4 8.04 Meiji 5,833 82.000 71.1 7.1 The numbers in the table are average plate movements for one particular volcano, and all of the volcanoes from this one particular volcano to Kilauea. Example: Rate of Plate Motion Cm/Yr. for East Molokai includes all of the plate motion from East Molokai to West Maui, and from West Maui to Haleakala, and from Haleakala to Kilauea. 10.) Fill in the correct answers in the spaces in Table 1. Column 4 is calculated as Km/MYrs., and Column 5 is calculated as (the answer in column 4) / 10. Or Cm/Yr. = (Km/MYrs.) / 10. 11.) __15.8 __ is the average for the column of the Rate of Plate Motion Cm/Yr. When calculating the average, do not include the 0 for Kilauea. 4

12.) Type below what happened to the numbers in Column 5 ( Rate of Plate Motion Cm/Yr.) from Meiji to Haleakala. The number from Meiji to Haleakala increased. 13.) List four of the five Volcanic Structure anomalies (outliers) that appear in the numbers for the Rate of Plate Motion Cm/Yr. column in Table 1. How to find the anomalies: You have already stated the general trend of the numbers in question 12.). Look at the numbers for the Rate of Plate Motion Cm/Yr . Do you see any number(s) that appear out of place in a sequence of three or four numbers (e.g. the numbers go down and then up, or the numbers go up and then down)? In a sequence of three numbers, try cover up one number at a time. If you cover up one number and the sequence of number above and below this numbers are following the trend, then you have found the anomaly. You may also have two numbers not following the trend. If this is the case, the number that seems farther from the trend is the anomaly. It is possible to also have two anomalies next to each other. In this case, you will need to look at a sequence of four numbers to discern the anomaly. Type your four Volcanic Structures below. Jingu, Yuryaku, Unnamed B, Unnamed A Determining the Rate of Plate Motion Between Two Volcanoes Table 2: In the following table, Km denotes Kilometers, MYrs. denotes Million Years, Cm denotes Centimeters, and Yr. denotes Years. Volcanic Structure To Volcanic Structure Distance Between Volcanoes (Km) Age Difference Between Volcanoes (MYrs.) Rate of Motion (Km/MYrs.) Rate of Motion (Cm/Yr.) Waianae Kilauea 374 3.700 101.1 10.1 Unnamed B Waianae 2,226 24.3 91.6 9.2 Yuryaku Unnamed B 920 15.4 59.7 5.9 Suiko (central) Yuryaku 1,274 16.2 78.6 7.9 Meiji Suiko (central) 1,039 22.4 46.4 4.6 14.) Fill in the correct answers in the spaces in Table 2 using the data from Table 1. You will need to calculate the difference in the distances for column 3, and you will need to calculate the difference in the ages for column 4. Column 5 and 6 of Table 2 are calculated similarly to columns 4 and 5 of Table 1. 15.) Where is the Rate of Motion (Cm/Yr.) the slowest (between what two volcanoes)? Between Meiji and Suiko 16.) Where is the Rate of Motion (Cm/Yr.) the fastest (between what two volcanoes)? Between Waianae and Kilauea 5