Walker lab 11

Colorado Online @ Astronomy 1110 Lab 11 T RENTON W ALKER N OVEMBER 3, 2023 A STRONOMY 1110 L AB 11: T HE G EOLOGY OF THE M ARTIAN S URFACE Section I: Surface Characteristics The Martian surface includes a wide range of geologies that vary by both latitude and longitude. In this section, we’ll be looking at the broader characteristics of the Martian surface. In the next section, we’ll dig into specific regions to see what their appearances can teach us about the history of Mars. 1. See the elevation map of Mars on the next page. Is there a noticeable difference in the crater density from north to south on Mars? Describe any difference you notice. There is a noticeable difference between the north and south on Mars. The northern section has maybe significantly less craters and the craters are more spread out than the souther section. 2. Based on what you have learned about the crater densities and ages of surfaces, do you see any difference in average age between the northern and southern hemispheres on Mars? Describe any difference you perceive. Due to the lack of craters relative to the southern half of Mars, the northern half seems to be much younger than the southern half. The southern half is higher in elevation and has more craters as well. 3. Identify a heavily cratered grid square. a. Specify its central latitude and longitude. -60  and -150  W b. Is it at high (white), low (blue), or intermediate (yellow) elevation? This is a intermediate to high elevation area. c. Is it in the southern or northern hemisphere? It is in the southern hemisphere. 4. Identify a smooth grid square. a. Specify its central latitude and longitude. +60  N +100  E b. Is at high (white), low (blue), or intermediate (yellow) elevation? This is a low elevation area. c. Is it in the southern or northern hemisphere? This is in the Northern hemisphere. Page 1

Colorado Online @ Astronomy 1110 Lab 11 5. Are the higher-elevation or the lower-elevation parts of Mars older on average? How do you know? The higher-elevation areas of Mars are older due to the amount of craters in those areas. Page 2

Colorado Online @ Astronomy 1110 Lab 11 Section II: Geology 6. Examine the volcanic Tharsis region on the map located on the previous page. a. Does it have few craters or many? The Tharsis region on the map has few craters. b. What does this tell you about the age of the Tharsis Bulge? The Tharsis Bulge is a younger area of mars. c. What type of feature is Olympus Mons? Olympus Mons is a volcano. d. Assume that the other mounts near Olympus Mons are features of the same type. How do these mountains connect to the relative age you inferred in part b)? These volcanoes are smaller but also relatively new compared to the southern regions. 7. Consider the mountains of the Tharsis Bulge and along the southeast edge of the Utopia Planitia. These mountains do not occur in chains. What does this tell you about Martian geology? ( Hint: Earth has many volcanoes in chains. This is evidence for what process? ) This tells us that Mars does not have tectonic plates like Earth does. 8. Based on the crater data , do you think the meteorite that created the Hellas Basin hit early or late in Mars’ bombardment period? Explain your reasoning. There is a belief the meteorite hit late in the bombardment period due to the less dense number of craters. 9. Examine the Tharsis Bulge and Mariner Valley in Figure 1. Which feature formed first? How do you know? It is believed the Tharsis Bulge formed first and created the Mariner Valley. The formations were probably formed around the same time and as a cause of one another. 10. Many astronomers think Mars may have had an ocean in its past. Assuming the Martian seas were similar to Earth’s oceans, they would have formed sedimentary rocks at the base of the ocean. a. Would rock beneath an ocean or sea be younger or older on average than rocks on other parts of Mars? Rock beneath an ocean would be younger than rocks on other parts of Mars. b. Would you expect to see a high density of craters in a region that was once beneath the ocean? Explain your reasoning. Page 4

Colorado Online @ Astronomy 1110 Lab 11 I would not expect to see a high density of craters in a region that was once beneath the ocean due to the water slowing the impact and the likeliness that area was younger than other areas. c. Where do you think the Martian ocean used to be? Explain your reasoning. I believe the Martian ocean used to be in the Northern hemisphere due to the low crater density and low elevation. 11. If you knew that Hellas Basin once hosted a small sea, would that change your answer to #8? Why or why not? It would not change my answer to #8 because it would make my answer make more sense with the meteorite hitting late in the bombardment period and the age of the area and elevation. 12. Kasei Valles (Figure 2, below) shows a complex network of canyons near the eastern boundary of the Tharsis Bulge. a. How does the elevation of the canyons near their western ends compare to the elevation at the eastern ends? The elevations of the canyons near the western ends are higher than the elevations of the canyons at the eastern ends. b. This region is at approximately latitude +25  and longitude -65  . Locate this feature on the map in Figure 1 and mark its location using the Draw or Shape tools. See figure 1. c. How do most canyons on Earth form? Most canyons on Earth form due to plate movement, and erosion and rivers. d. Is the presence of Kasei Valles consistent with your conclusion in #10? Explain your reasoning. This is consistent with my conclusion as it appears that these canyons in the Northern hemisphere are like rivers stemming from an ocean in the Northern hemisphere. Page 5

Colorado Online @ Astronomy 1110 Lab 11 northern hemisphere of Mars is younger than the southern hemisphere. There is also the discovery of a likely ocean in the Northern hemisphere due to the canyons and lower elevations and crater density. References: Astronomy 2E . Openstax, 2022. Page 7