I\'m not sure if I am doing this right or not and could use some help. The botto
ID: 107748 • Letter: I
Question
I'm not sure if I am doing this right or not and could use some help. The bottom picture is for part 4 of this question. Please be detailed so I can understand where I am going wrong. Thank you!seismology (the study of structure and composition using earthquake waves, mantle xenoliths, and laboratory experiments indicate that the u mantle is rock. peridotite density of about and is capable of slow flow. also reveals the thicknesses of crust and mantle layers. 1. Seismology indicates that the average thickness of basaltic ocean crust is about 5.0 km. Use the average density of basalt (from part A above) and your (Activity 1.5, tem D) to calculate how high (in kilometers basalt floats in the man Show your work. I- 3, 3.3 glcmil 0,934 30 39 sa O. 30 km alt conts n the mantle 2. Seismology indicates that the average thickness of granitic continental crust is about 30.0 kilometers. Use the average density of granite (from part B above) and your isostasy equation (Activity 1.5, item D to calculate how high (in kilometers) granite floats in the mantle. Show your work. 2.8 3.3 e the 30. ST 5 k Aveof. D or mile 2.2 3. What is the difference in km) between your answers in C1 and C2? 4. How does this difference between C1 and C2 compare to the actual difference between the average height of continents and average depth of oceans on the hypsographic curve (FIGURE 1.11c)?
Explanation / Answer
(1)As per the values in hand we know 1-(L0/L1) gives the proportion of rock 1 to protrude out of rock 2.
1-(3.11/3.3) = 1 - 0.942424242 = 0.068 is the proportion of the lighter rock that will be above the surface of the heavier rock. Therefore, 5.0 * 0.058 = 0.34 km will be above the surface of the mantle.
As the two rocks are close in density, it is expected the lighter to go lower in the medium like ice is in water. 0.29 km would be floating above the surface.
(2) As the Earth's surface solidified some areas formed less dense granitic crust that formed the high standing continents and some areas formed somewhat more dense basaltic crust that became the ocean basins. As the Earth continued to cool it contracted. The boundaries between the oceans and continents were prime zones of focused stresses. The contraction caused down-warped troughs to form near the edges of the continents. These troughs were filled with sediments produced by weathering on the continent. The deposited sedimentary layers were deformed and folded and uplifted as a result of continued cooling and contraction. Therefore your answer is correct.
(3)C1 = 0.34 , C2 = 2.80.
(4) Hypsometric curve, also called Hypsographic Curve, cumulative height frequency curve for the Earth’s surface or some part thereof. A hypsometric curve is essentially a graph that shows the proportion of land area that exists at various elevations by plotting relative area against relative height. In the hypsometric curve of the total Earth surface there exist two maxima of frequencies at the 100-metre (109-yard) and the 4,700-metre (5,140-yard) elevations, which correlate with the mean level of the lowland continental areas and the deep-sea floor. This aspect of the Earth’s surface, revealed by hypsometric analysis, supports the theory of a crust consisting of simatic (peridotitic, specific gravity about 3.3) materials under the oceans and of sialic (granitic to gabbroic, specific gravity about 2.7) materials of the continents. As we notice in the figure provided, this part of the line has a fairly steep slope. If we look at the y-axis of the graph, we can see that continental margins are found from 0 to 4 km depth in the ocean. If we look at the x-axis, we can determine that continental margins represent about 20% of the earth’s surface.