CHANNELS ON MARS KWL Prior Knowledge/Engagement Activity In your small group, brainstorm ideas about what you think you know about channels and what questions you have about channels on Mars. You will revisit the third column throughout your investigation. What do we know about channels on Mars? (What they look like, how they were formed, when were they formed?) What questions do we have about channels on Mars? What have we learned about channels on Mars? 1
CHANNELS ON MARS Objectives 1. Identify different types of channels on Mars and interpret how they have formed. 2. Become familiar with remote sensing terminology associated with the Mars Odyssey satellite. 3. Use geologic relationships of the many different features that often interact with channels on Mars to determine the order of events that shaped an area. Background Information THEMIS There are three instruments on the Mars Odyssey spacecraft. This activity uses images taken by one of them called the Thermal Emission Imaging System or THEMIS. THEMIS is composed of two cameras, a visual camera (VIS) and an infrared camera (IR). The visual camera takes a picture of the surface of Mars as it is during the daylight hours. The infrared camera can take a picture of the surface during either day or night because it is acquiring heat differences. Different rock materials on the surface of Mars radiate different intensities of heat. Planetary geologists can use both the VIS and IR data (together or separately) to help them map Mars. (See Chapter 5 in the Mars Student Imaging Project Resource Manual for more detailed information.) Basic Mars Geologic Facts There are many fascinating geologic features on Mars. The major rock type found on Mars is igneous. Mars is famous for its volcanoes, including the largest known volcano in our solar system, Olympus Mons. Below is an image of another volcano, Apollonaris Patera (9.8 S, 174.4 E). This image shows the remains of the caldera located on the top of this old volcano. This volcano is near Gusev Crater where one of the Mars Exploration Rovers landed. The channels radiating out from the volcano were formed by lava flows, which can erode like rivers of water, except that they are made of hot, liquid rock instead! 10 km Meteor craters, ~10 km wide. Channels formed by lava. Large lava flow in the shape of a delta. Figure 1. Apollonaris Patera. Image ID: I01630002 2
As seen in the Apollonaris Patera image, Mars has an amazing variety of craters. In fact, because we haven t yet brought any rocks back from Mars to analyze how old they are, craters are used to determine the relative age of surfaces on Mars; in general the more craters an area has, the older it is. Geologic features such as collapsed lava tubes (sometimes know as pit chains) can also form features that look like water-carved channels. These collapsed lava tubes are geologic features through which lava once flowed underground. Once the lava is gone, these tubes often collapse, forming channel-like features. Mars currently has no liquid water on its surface and very little water vapor in its atmosphere (it never rains!). There are, however, many channels that must have been formed by water. Just because there is no liquid water on the surface right now, doesn t mean that in early Mars history, when the planet was warmer, that there weren t oceans, lakes or rivers. Modern Mars water cycle is composed of polar ice caps made of water and carbon dioxide and the frozen groundwater (permafrost) underneath its surface. Geologists conclude that another way to have liquid water on Mars is to create huge floods of water that came from melting frozen groundwater with geothermal activities, i.e., erupting volcanoes and hotspots. Chaotic terrain is one geologic feature thought to be associated with melting frozen groundwater and these floods of water. Tear-drop shaped island. Water flowed north. 3 km Braided channels formed by water. Collapsed lava tubes, pit chains. Figure 2. Elysium Planitia near Isidis Planitia. Image ID: V01868003 (21.6 N,125.5 E) 3
Figure 3. THEMIS image of Martian chaotic terrain. (http://themis.asu.edu/features/ianichaos) Another major channel-like feature of the planet is Valles Marineris, the Grand Canyon of Mars. Interestingly, this huge (as wide as the USA!) canyon was formed primarily through tectonic forces opening the crust of Mars. But this is different from the Grand Canyon of Arizona, which has experienced ongoing erosion by the Colorado River as the Colorado Plateau has been uplifted. If you put a knife on the top of a stick of butter and then lifted the butter to cut through it, this would model the process of the river cutting through the crust of the Earth. Despite this initial difference, on both Mars and Earth the canyons have been greatly modified by landslides, wind erosion, and minor faulting. Landslides modifying the canyon wall. Wind erosion seen behind some craters. Chaotic terrain Figure 4. Eastern Valles Marineris (Ganges Chasma) showing channels with craters, slope failure, chaotic terrain and wind erosion. (cropped image taken from infrared map of Mars available at http://www.google.com/mars/) 4
CHANNELS ON MARS Data Collection /Exploration Activity Directions: 1. Go to the THEMIS web site: http://themis.asu.edu 2. Once you reach the homepage click on Image Gallery (the yellow series of buttons on the left side of the page), then Images by Topic, and then click on Channels. 3. Once this page opens you will see the first of three pages of images of channels on Mars (see Figure 3 below). These pages compose the catalogue of available channel images. The small pictures ( thumbnails ) here are just small sections of the full images. 4. To view an entire image click on any thumbnail picture. This view gives you basic information about the image: the latitude and longitude of the image on Mars, when it was taken, which camera took the picture (VIS or IR), the image s size, and its resolution and also context image information. In order to get the image identification number you need to click on the THEMIS Data Releases link on the right side of the page. 1 2 3 4 5 6 7 8 9 10 11 12 A B C D E F G Page # Figure 5. Image gallery of channels on Mars (http://themis.asu.edu, 11/23/05). H 5. Your teacher will assign you a group of images to analyze. Circle the images on the grid in Figure 5 (including what page #) to help you keep track of your images. Use the features labeled in the background information section to help you identify the different geologic features on your assigned images. 5
6. IMPORTANT!!! Read the information written on the right hand side of the web page in order to get some ideas about what you may be looking at in your image. Also, in order to see the enlarged detail of your image do the following: a. Click on the THEMIS image so you can view the entire image on the page. b. Click on the THEMIS image one more time, or move the mouse over the lower, right-hand corner of the page where a square button will appear allowing you to click to enlarge the image. This will allow you to see much greater detail of the features within the image. (You will have to scroll around to look at it and it will be much more interesting to look at!) Remember: Click on the link that says THEMIS Data Releases link in order to find the image identification number. Now you re ready to map the channels and other features of Mars! Data collection should be done carefully. Data Collection Use the data tables provided on the next few pages to record information about your image. Be sure to describe all the significant characteristics of the images such as: shape and relative depth of the channel, steepness of the slope, collapse features (lava tubes, pit chains), landslides, scour marks (erosion), any cross-cutting relationships (if one feature cuts another, it is younger than the feature it cuts across), ripples or dunes (deposition and wind activity), and features you may be unable to identify. 6
CHANNELS ON MARS -Data Collection /Exploration Activity Mars THEMIS Image Data Page: Row: Number: Latitude: Longitude: Image ID: Date Taken: Instrument Used: VIS IR Date Released: Image Size: Resolution: Sketch Map of Image Description of the image: Location of features that are interesting, but don t know what they are: 7
CHANNELS ON MARS - Data Collection /Exploration Activity Mars THEMIS Image Data Page: Row: Number: Latitude: Longitude: Image ID: Date Taken: Instrument Used: VIS IR Date Released: Image Size: Resolution: Sketch Map of Image Description of the image: Location of features that are interesting, but don t know what they are: 8
CHANNELS ON MARS - Data Collection /Exploration Activity Mars THEMIS Image Data Page: Row: Number: Latitude: Longitude: Image ID: Date Taken: Instrument Used: VIS IR Date Released: Image Size: Resolution: Sketch Map of Image Description of the image: Location of features that are interesting, but don t know what they are: 9
CHANNELS ON MARS - Data Collection /Exploration Activity Mars THEMIS Image Data Page: Row: Number: Latitude: Longitude: Image ID: Date Taken: Instrument Used: VIS IR Date Released: Image Size: Resolution: Sketch Map of Image Description of the image: Location of features that are interesting, but don t know what they are: 10
CHANNELS ON MARS Presentation of Observations/Explanation Activity A. Choose one of the images you sketched and observed to explain to your classmates what you have discovered. You can do this by: 1. Sketching your image on a large piece of paper to illustrate important findings to your classmates. 2. Display the image in the front of the room using a projector. Use the chart below to be sure to include the following in your presentation: Identified Geologic Features Information regarding the interpretation of the geologic history of the area What you wish to further investigate based on your observations of your image (Elaboration Activity) B. During each group s presentation, create a list of vocabulary terms (which can include geologic features identified). Vocabulary Term or Geologic Concept Definition or Formation Process Sketch (if applicable) 11
CHANNELS ON MARS Presentation of Observations/Explanation Activity (continued) Vocabulary Term or Geologic Concept Definition or Formation Process Sketch (if applicable) 12
CHANNELS ON MARS Research Planning/Elaboration Activity A. List what question you wish to further elaborate on as part of an investigation you conduct. Be sure your question focuses on a geologic feature associated with channel-forming processes. 1. What research question do you wish to further investigate based on your observations? 2. On what geologic feature does your research question focus? B. Elaborate on your plan of how you will conduct your research. Consider using resources like the Internet or using resources from your school or local library. Create a list of steps of how you plan to gather information to help answer this question. Identify what resources you will look for and who is responsible for each specific task 13
CHANNELS ON MARS Creating Your Research Poster/Evaluation Activity Create a poster diagramming and explaining your interpretation of the geology of the selected feature(s) associated with your research question.. 1. Select one of your original four images to investigate in greater depth. 2. Print out or sketch a copy of your image (and other images if you wish) and label all features of interest. Include labels for features, such as craters, to show which feature was created first, i.e., which is older. 3. Along with your image information, include your research question and research you have done on the different geologic features that you are focusing on. 4. Reference all sources of information, including the THEMIS website. Suggestions: A. Sketch a rough draft of you poster before finalizing your poster format. B. Use the Rubric for Poster Assessment to understand how your poster will be evaluated. Rubric for Poster Assessment Exemplary Meets Standards Partially Meets Standards Redo All information is complete, accurate and detailed. Selected THEMIS image(s): features have been thoroughly labeled. Correctly cited image information. Neatly presented and logically organized. No spelling or grammatical errors. All information is complete and accurate. Selected THEMIS image(s): most features have been labeled. Correctly cited image information. Neatly presented and generally organized. No spelling or grammatical errors. Some information is missing; all others are complete and accurate. Selected THEMIS image(s): some features have been labeled. Partially cited image information. Generally organized, but not as neat as it could be. Few spelling and/or grammatical errors. A lot of information is missing. Selected THEMIS image(s): few features have been labeled. No cited image information. Disorganized and sloppy. Multiple spelling and/or grammatical errors. 14