I. Introduction What is your science question? Is there a relationship between local base plateau elevation and depth, width, and length of channels within them? Why is this question important and interesting? This question is important for the following reasons: 1. Could provide insight into the erosional forces that were active on mars. 2. Could provide us with more insight into the similarities and differences between hydro erosional forces on Earth and Mars. List any hypotheses you may have had of what the answer(s) might be to your science question. 1. As the average base elevation increases, the channel will become deeper, wider and longer. II. Background Hydraulic Action is the ability of flowing water to dislodge and transport rock particles or sediment is called hydraulic action. In general, the greater the velocity of the water and the steeper the grade, the greater the hydraulic action capabilities of the stream. Hydraulic action is also enhanced by a rough and irregular stream bottom, which offers edges that can be grabbed by the current and that create uplifting eddies. Abrasion is the process by which a stream's irregular bed is smoothed by the constant friction and scouring impact of rock fragments, gravel, and sediment carried in the water. The individual particles of sediment also collide as they are transported, breaking them down into smaller particles. Generally the more sediment that a stream carries, the greater the amount of erosion of the stream's bed. The heavier, coarser grained sediment strikes the stream bed more frequently and with more force than the smaller particles, resulting in an increased rate of erosion. Circular depressions eroded into the bedrock of a stream by abrasive sediments are called potholes. The scouring action is greatest during flood conditions. Potholes are found where the rock is softer or in locations where the flow is channeled more narrowly, such as between or around boulders. Solution rocks susceptible to the chemical weathering process of solution can be dissolved by the slightly acidic water of a stream. Limestones and sedimentary rock cemented with calcite are vulnerable to solution. The dissolution of the calcite cement frees the sedimentary particles, which can then be picked up by the stream's flow through hydraulic action. CliffsNotes.com. Stream Erosion. 18 Oct 2012 < http://www.cliffsnotes.com/study_guide/topicarticleid 9605,articleId 9511.html>. Stream Flow and Sediment Transport Stream velocity is the speed of the water in the stream. Units are distance per time (e.g., meters per second or feet per second). Stream velocity is greatest in midstream near the surface and is slowest along the stream bed and banks due to friction.
Hydraulic radius (HR or just R) is the ratio of the cross sectional area divided by the wetted perimeter. For a hypothetical stream with a rectangular cross sectional shape (a stream with a flat bottom and vertical sides) the cross sectional area is simply the width multiplied by the depth (W * D). For the same hypothetical stream the wetted perimeter would be the depth plus the width plus the depth (W + 2D). The greater the cross sectional area in comparison to the wetted perimeter, the more freely flowing will the stream be because less of the water in the stream is in proximity to the frictional bed. So as hydraulic radius increases so will velocity (all other factors being equal). Stream discharge is the quantity (volume) of water passing by a given point in a certain amount of time. It is calculated as Q = V * A, where V is the stream velocity and A is the stream's cross sectional area. Units of discharge are volume per time (e.g., m 3 /sec or million gallons per day, mgpd). At low velocity, especially if the stream bed is smooth, streams may exhibit laminar flow in which all of the water molecules flow in parallel paths. At higher velocities turbulence is introduced into the flow (turbulent flow). The water molecules don't follow parallel paths. Streams carry dissolved ions as dissolved load, fine clay and silt particles as suspended load, and coarse sands and gravels as bed load. Fine particles will only remain suspended if flow is turbulent. In laminar flow, suspended particles will slowly settle to the bed. Hjulstrom's Diagram plots two curves representing 1) the minimum stream velocity required to erode sediments of varying sizes from the stream bed, and 2) the minimum velocity required to continue to transport sediments of varying sizes. Notice that for coarser sediments (sand and gravel) it takes just a little higher velocity to initially erode particles than it takes to continue to transport them. For small particles (clay and silt) considerably higer velocities are required for erosion than for transportation because these finer particles have cohesion resulting from electrostatic attractions. Think of how sticky wet mud is. http://myweb.cwpost.liu.edu/vdivener/notes/streams_basic.htm III. Methods What specific spacecraft and camera did you use to collect data for your research? 1. THEMIS 2. MOLA Colorized 3. JMARS The focus of our research was investigating vallis channels all over the Martian surface. We used the JMARS data base platform. 1. Open the following layers: THEMIS Stamps, MOLA Colorized Maps, Nomenclature (Vallis) 2. We broke into groups that each individually recorded the necessary observations.
We decided the following data was important to collect in order to answer our hypothesis. Latitude and Longitude This is important to know exact location and can be used to determine (in degrees) the distance from the other features observed. MOLA Cross Section Profile Line We collected elevation, width and depth for each Vallis observed. With the MOLA profile line data, we calculated out: Change Change Greatest IV. Data Region Long, Lat Profile Line 1 Profile Line 2 Profile Line 3 Total Length (km) Total CHANGE Total CHANGE Greatest AVG (m) Width (km) (m) Width (km) (m) Width (km) Hrad Vallis 135.89E, 4233 100 10.5 4350 80 13 4450 60 8 405km 217 40 4233 80 38.18 Apsus Vallis 141E, 34 3686 631 17.5 3827 457 15 4000 232 5 200km 314 85 3686 440 Minio Vallis 208.27E, 1769 475 6 2270 850 5.5 2772 750 635 78km 1003 275 1769 692 4.58 Mamers Vallis Region 20.2E, 31.6N 1700 300 6 2000 500 9.5 2000 350 10 110km 300 50 1700 383 Ares Vallis 340.422E, 800 1100 68 1900 3500 60 3000 1900 110 1200km 2200 800 800 2166 7.812 Deva Vallis 204E, 7.742 661 650 23 794.5 900 10 928 600 9 170km 267 50 661 716 Scamander Vallis 28.9E, 14.82 315 260 18 625 330 15.5 1142 210 7 208km 827 50 315 266
3500 Total Vallis Change Vs. Total Change 3000 2500 2000 1500 CHANGE Total CHANGE 1000 500 0 1 2 3 4 5 6 7 8
Highest Base Vs. Average of Vallis AVG 2166 716 266 1 2 3 4 5 6 7 315 800 661 692 383 1769 1700 4233 80 440 3686
0 500 Greatest Vs. Average Width 1 2 3 4 5 6 7 8 1000 1500 Axis Title 2000 2500 AVG Width Greatest 3000 3500 4000 4500
V. Discussion Could there be inaccuracies and misinterpretations? If so, please explain. 1. The Vallis measurements were completed with MOLA. In a lot of cases, there were not THEMIS images available to provide the high detail and resolution to be extremely precise and accurate. 2. Human error: We had 8 separate groups collecting data. Each group had their own intrinsic level of effort and focus on detail. 3. There also could have been misinterpretations of where to begin/ end measurements. 4. We question the reliability of JMARS. We would get a different number of THEMIS images for any one region each time we would open the THEMIS stamp layer. Observations of Data: 1. Very clear pattern 2. Does support our hypothesis There is a direct relationship with all the graphs we produced supporting our hypothesis. Axis Title Greatest Vs. Average Width 0 5000 12345678 AVG Width Greatest Highest Base Vs. Average of Vallis 716 800 661 315 266 1 2 3 692 4 1769 1700 383 5 6 7 4233 80 440 3686 AVG 2166 4000 3000 2000 1000 0 Total Vallis Change Vs. Total 1 2 3 4 5 6 7 8 CHANGE Total CHANGE
VI. Conclusions What is your science question? Is there a relationship between local base plateau elevation and depth, width, and length of channels within them? We hypothesized that as the average base elevation increases; the channel will become deeper, wider and longer. We found that are observations and analysis of the data does support our hypothesis. This represents areas of future research that could be valuable in answering our hypothesis. 1. Are there any other fluid possibilities to create the Vallis on the mars surface? 2. Is there evidence that there is flowing water sub surface currently on mars? Acknowledgements 1. Jessica Swann (Coordinator of program) 2. JMARS *See references 3. THEMIS *See references 4. MSIP and ASU *See references VI. References Christensen, P.R., N.S. Gorelick, G.L. Mehall, and K.C. Murray, THEMIS Public Data Releases, Planetary Data System node, Arizona State University, <http://themis data.asu.edu>. Christensen, P.R., B.M. Jakosky, H.H. Kieffer, M.C. Malin, H.Y. McSween, Jr., K. Nealson, G.L. Mehall, S.H. Silverman, S. Ferry, M. Caplinger, and M. Ravine, The Thermal Emission Imaging System (THEMIS) for the Mars 2001 Odyssey Mission, Space Science Reviews, 110, 85 130, 2004. Watt, K. (2002). Mars Student Imaging Project: Resource Manuel. Retrieved June 29, 2006, retrieved Sept 2012 from Arizona State University, Mars Student Imaging Project Web site: http://msip.asu.edu/curriculum.html. CliffsNotes.com. Stream Erosion. 18 Oct 2012, http://www.cliffsnotes.com/study_guide/topicarticleid 9605,articleId 9511.html http://myweb.cwpost.liu.edu/vdivener/notes/streams_basic.htm