Mass Balance of Martian Sedimentary Fans and Valleys APPROVED BY

Home , Peace Vallis

The Thesis Committee for Katherine Rose Shover Certifies that this is the approved version of the following thesis:

Mass Balance of Martian Sedimentary Fans and Valleys

APPROVED BY SUPERVISING COMMITTEE:

Supervisor: John W. Holt

Wonsuck Kim

Lorena Moscardelli

Mass Balance of Martian Sedimentary Fans and Valleys

Katherine Rose Shover, B. A.

Thesis Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of

Master of Science in Geological Sciences

The University of Texas at Austin May 2015

Acknowledgements

I would like to thank my advisor, Dr. Jack Holt, for welcoming me into his research group and setting me up with this amazing research project. I would also especially like to thank Dr. Tim Goudge and Dr. Joe Levy for their incredibly helpful and timely feedback. This thesis would not have been possible without them. I would like to thank the members of my committee – Dr. Lorena Moscardelli and Dr. Wonsuck Kim – for their time and guidance on this work. Thank you to Dr. David Mohrig for his insightful comments. Thank you to the QCL for allowing me to use their workstation and for making me feel like a part of the community. Many thanks to my friends at UT, particularly the Martians, who have made my time here enjoyable. I especially would like to thank Rebecca Jones for being a fantastic friend and a major support through both the good times and the bad.

To my professors at DePauw University – especially Dr. Tim Cope and Dr. Jim Mills – thank you for inspiring my love of geology and pushing me to excel and to reach for the stars. To my family, thank you for the lifetime of support I have received. Mom, Dad, Cheryl, Melissa, and Sarah, even from afar, you have been a huge positive presence in my life. To my grandparents, thank you for the phone calls supporting me through everything from multiple car failures to general stress. I appreciate that I could always rely on you for help. Matthew Hellmann, you have been my #1 supporter throughout this graduate school experience. Thank you for your strength, levity, and guidance. The excellent cooking didn’t hurt, either. Love you lots! iv Abstract

Mass Balance of Martian Sedimentary Fans and Valleys

Katherine Rose Shover, M.S. Geo. Sci. The University of Texas at Austin, 2016

Supervisor: John W. Holt

Dozens of sedimentary fans have been identified on Mars and have been interpreted as alluvial fans or deltas. However, the extent to which these deposits represent the complete eroded mass of the valleys that drain into them, the extent to which erosion has removed fan material, and the extent to which sediment bypass occurred during fan deposition into a distal water body remain unknown. This study investigates the role of emplacement versus modification following deposition in a catalog of martian fans to determine the extent to which such deposits have been preserved. A mass balance approach was taken; by calculating the present volumes of fans and the valleys feeding them, the percentage of eroded valley sediment that has accumulated and remained within the fan deposits can be determined. Based on measurements of 32 valley and fan volumes calculated using CTX stereo DEMs, we find two major classes of landforms: isolated inlets with lower stream orders and fans of approximately equal volume to the source valleys, and regionally-integrated valley networks with higher stream orders and much smaller fan volumes than valley volumes. If stream order correlates with valley age on Mars, then these results imply change in v martian erosion and deposition patterns over time. We infer that hydrodynamic sorting in older, wetter systems resulted in preferential deposition of fines in fans formed by higher stream order valleys, and, ultimately more erosion in these fine-grained deposits, while younger, drier systems created deposits with intermixed sediment sizes that remain preserved today due to the greater protection of the fines from post-depositional erosion. These observations are consistent with a waning hydrologic cycle throughout martian history.

vi Table of Contents

List of Tables ...... viii

List of Figures ...... ix

Introduction ...... 1

Methodology ...... 6

Results ...... 9

Discussion ...... 11 Gale Crater ...... 14

Conclusions ...... 15

Appendix ...... 16 Introduction ...... 16 Methodology ...... 23 Fan Length vs. Width Study ...... 27 Complete Volume Results ...... 28 Methods Comparison ...... 32 Open vs. Closed Basins and Sediment Volume Ratios...... 34 Volume Calculations From Other Studies ...... 37

References ...... 42

Vita… ...... 46

vii List of Tables

Table A1: Volume calculations from other studies ...... 38 Table A2: Fan locations and references ...... 39-40

Table A3: Stream order and raw results for each method ...... 41

viii List of Figures

Figure 1: Distribution of fans for this study and four example fans ...... 4 Figure 2: Volume calculation method illustrations...... 7 Figure 3: Graph relating valley volumes, fan volumes, and stream order ... 8-10 Figure A1.1: Fans surveyed in this thesis with coordinates and image sources ....17 Figure A1.2: Fans surveyed in this thesis with coordinates and image sources …18 Figure A1.3: Fans surveyed in this thesis with coordinates and image sources ....19

Figure A1.4: Fans surveyed in this thesis with coordinates and image sources20-20 Figure A1.5: Fans surveyed in this thesis with coordinates and image sources ....22 Figure A2: Example of 2nd-order polynomial trend surface correction ...... 25 Figure A3: Strahler order determination example ...... 26 Figure A4: Graph of fan length vs. fan width ...... 27 Figure A5: Graph of best method (Method C) fan volume by valley volume according to stream order, including trendlines...... 28

Figure A6: Graph of average results from all four methods ...... 29 Figure A7: Graph of Method A results ...... 29 Figure A8: Graph of Method B results ...... 30 Figure A9: Graph of Method D results ...... 30

Figure A10: Fan with infilled valley ...... 31 Figure A11: Graph of fan volume results plotted by method...... 32 Figure A12: Graph of valley volume results plotted by method...... 33

Figure A13: Distribution of open and closed basins and results from sediment ratio formula ...... 35 Figure A14: Graph of sedimentary fans in open basins and closed basins ...... 36

ix Introduction

Evidence for ancient (Noachian) fluvial activity on Mars is widespread, and consists of both erosional landforms (e.g., valley networks and breached craters that form open-basin lakes) and depositional landforms (e.g., sedimentary fans) [Baker 2001, Fassett and Head 2008b]. Fluvial activity likely post-dates the formation of the large basins on Mars that occurred in the early to mid Noachian [Fassett and Head, 2011], but may record secular changes in water availability at the martian surface. Irwin et al. [2005] propose a history of valley network development on Mars in which prolonged but slow highland gradation occurred during the Noachian period, followed by entrenchment of immature valley networks in the late Noachian to early Hesperian. Subsequently, valley reactivations and new valley development occurred on and off during the Hesperian and perhaps the Noachian. Irwin et al. [2005] indicate several lines of evidence for this progression, such as deposition of sedimentary fans during a late stage of contributing valley entrenchment, brief erosive responses to declines in base level in fluvial valleys crosscutting the scarp of the highland-lowland boundary, and late-stage breaching of enclosed basins previously modified only by internal processes. Likewise, Howard et al. [2005] emphasize the ephemeral nature of the earlier Noachian fluvial activity, as opposed to the regional integration of drainage networks from the final epoch of widespread fluvial action. Researchers such as Baker [2001] have worked to determine the water budget on

Mars through time, describing Mars’ potential transition from a warmer, wetter planet in the late Noachian/early Hesperian to the cold, dry world seen today. However, as Baker [2001] mentions, up to 25-35% of Martian valleys may be Hesperian or Amazonian in age, suggesting the possibility of intermittent fluvial activity in Mars’ more recent 1 history. Analysis of age based on crater morphology by Mangold et al. [2012] also supports this idea. They found that craters with fluvial landforms had more in common with fresh craters with preserved ejecta as opposed to degraded craters dating to ~4 Gyr to ~3.7 Gyr, which suggests that fluvial activity may have occurred at later dates. Sedimentary fans are another piece of evidence indicating past martian fluvial activity. Dozens of these features have been identified on Mars and interpreted as alluvial fans and deltas (e.g., Moore et al [2003]). For this study, the terms “fans” and

“sedimentary fans” are used as generic terms to describe both of the aforementioned types of deposits. These sedimentary fans formed as a result of fluvial erosion, transport, deposition, and accumulation of sediment. Questions remain regarding 1) the extent to which such deposits have been preserved, and 2) the role of emplacement, in either the fan deposit or further out in the basin, versus modification following deposition [Malin and Edgett 2003, Schon et al. 2012, and Goudge et al. 2012, 2015]. In order to address these questions, we quantified the mass balance of 32 fan/valley systems by comparing present volumes of the fans to the volumes of the valleys that fed them. Volume is used as a proxy for mass in this study; a mass balance, and not a volume balance, is required for this study because mass must be conserved, whereas volume does not. Mass balance calculations can help constrain the extent to which systems have been modified following deposition, or constrain the amount of sediment that bypassed the fan during deposition. Three possible results may exist: (1) the volume of the fan is approximately equal to the volume of the valley, which means that valley mass is mostly preserved in the fan system; (2) the volume of the fan is much less than the volume of the valley, which indicates that either the fan deposit has been heavily eroded subsequent to formation, and/or that much of the sediment eroded from the valley is not contained in the associated fan deposit; (3) the volume of the fan is much greater than the volume of 2 the valley, which could indicate either preferential infilling of valleys over removal of fan material, or large amounts of landscape erosion not expressed in preserved, incised valleys. By calculating present volumes of the fans, and the volumes of the valleys feeding them, we can determine the percentage of eroded valley sediment that has remained within the fan deposits to help assess if and how the timing of fluvial activity manifests itself in fan deposits and valleys. Previous workers have employed similar approaches for calculating fan volumes [e.g., Moore et al. 2003, Mangold and Ansan 2006, Buhler et al.

2014, Palucis et al. 2014, and Salese et al. 2016], including some mass balance studies of individual or regional groups of martian sedimentary fans [Malin and Edgett 2003, Jerolmack et al. 2004, Bhattacharya et al. 2005, Fassett and Head 2005, Kleinhans et al. 2010, and Mangold et al. 2012]. However, here we build on earlier work by applying this methodology to a larger, more extensive catalog of deposits and by applying volume measurements derived from high-resolution Context Camera (CTX) stereo digital elevation models (DEMs) (Fig. 1).

Figure 1: (a) The 32 fans analyzed in this study, from a catalog of 108 fan deposits compiled from previously published results. Fan coordinates can be found in the Appendix. (b) Fan fed by an isolated inlet valley at -6.5° N, 141.2° E. Fans and valleys are mapped in blue and red outlines, respectively. Figure is a portion of CTX-derived DEM from stereo-pair images B01_009874_1735 and B22_018366_1735 overlain on CTX image B01_009874_1735.

4 Figure 1 Continued: © Example sedimentary fan fed by a valley network at 12.0° N, - 45.0° E. Figure is a portion of CTX-derived DEM from stereo-pair images D18_034394_1920 and B07_012373_1915 overlain on CTX image D18_034394_1920. The inset is a portion of the THEMIS ~100m/pixel global daytime infrared mosaic, depicting the full length of the valley. (d) Gale Crater Peace Vallis fan fed by an isolated inlet at -4.5° N, 137.3° E. Figure is a portion of CTX-derived DEM from stereo-pair images G04_019698_1747 and G04_019988_1747 overlain on CTX image G04_019698_1747. (e) Gale Crater sedimentary fans fed by a valley network at -5.8° N, 137.3° E. Figure is a portion of CTX-derived DEM from stereo-pair images P15_006855_1746 and D15_033082_1746 overlain on CTX image P15_006855_1746.

5 Methodology

Mars Reconnaissance Orbiter Context Camera (CTX) [Malin et al. 2007] stereo- derived digital elevation models (DEMs) were used to constrain the volumes of the fans and the valleys that feed them. DEMs were produced using the NASA Ames Stereo Pipeline [Smith et al. 2001, Broxton et al. 2008, Moratto et al. 2010, and Beyer et al. 2014], and were tied to Mars Orbiter Laser Altimeter (MOLA) point shot data to correct for error in regional slope [Smith et al. 2001]. Sites were selected from a catalog of fan deposits [Forsythe and Blackwelder 1998, Cabrol and Grin 1999, Ori et al. 2000, Cabrol and Grin 2001, Grant and Parker 2002, Malin and Edgett 2003, Howard and Moore 2004, Fassett and Head 2005, Harrison and Grimm 2005, Di Achille et al. 2006, Mangold and Ansan 2006, Mangold et al. 2007, Irwin 2007, Hauber et al. 2009, Di Achille and Hynek 2010, Goudge et al. 2012, Hauber et al. 2013, and Palucis et al. 2014,] based on the availability of stereo CTX coverage over the area of the fan and at least a portion of the channel (Fig. 1).

A suite of four methods were used to calculate the volume of the fans and feeding valleys, all of which involve calculating the volume contained between a reference surface and the fan surface or the valley floor (Fig. 2).

Figure 2: Block diagram and cross-sectional schematic illustrations of the four methods used for volume estimation of the fans and valleys. The four methods involve calculation of the volume between the fan surface or valley floor (blue) and: (a) a flat plane at the base of the fan/rim of the valley, (b) a best-fit dipping plane, (c) a segmented, dipping plane, and (d) a 2nd-order polynomial surface (all red). Method D is only used for the fan. Additional methodological details are included in the supplementary material.

The primary difference between each of the four methods is the way in which we calculate the reference surface. The first method uses a flat reference plane at the average elevation of the valley rim or the crater floor as measured at the fan toe (Fig. 2a). The second method uses a reference surface of a dipping plane fit to the elevation values at the edge of the fan or the valley rim (Fig. 2b). The third method uses a reference surface of a segmented, dipping plane fit from contours typically spaced at 50 m intervals (Fig. 2c). The fourth method (for fan volume only) uses a reference surface defined by a second-order polynomial fit to the elevation values at the edge of the fan (Fig. 2d). Some of these methods will tend to overestimate volumes (e.g., Fig. 2a), while some will tend 7 to under-estimate volumes (e.g., Fig. 2b and supplemental Fig. A11 and A12), so the range of values from all four methods provides a bound on the fan and valley volume. For cases in which the valleys were not entirely covered by DEMs, we used the portion covered to calculate an average cross-sectional area and then multiplied by the total length of the valley system to obtain an estimate of the full valley’s volume. To sub-divide the fans into groups based on the level of valley integration, the Strahler order for each stream was calculated. Strahler orders for valleys on Mars are likely to appear lower than their terrestrial counterparts, due to a combination of landscape erosion, valley infilling and resolution limits from orbital remote sensing data. According to Hynek and Philips [2003] and Hynek et al. [2010], values on Mars for stream order and drainage density fit with similarly-calculated lower-end estimates for valleys on Earth.

8 Results

The calculated volumes of the fans range from 0.03 km3 to 51.3 km3, and the valley volumes range from 0.2 km3 to 520.6 km3. Of the four methods used to calculate volumes, Method C (Fig. 2)—the segmented plane—tend to fall between the values provided by the other methods and represent our best estimate of the true volumes of the fans and valleys (See Appendix for further discussion). Fan volume and valley volume are shown in Figure 3a. The majority of fan/valley pairs have lower fan volumes than valley volumes and thus fall below the 1:1 line. However, in two cases fan volume exceeds valley volume: the Gale Crater Peace Vallis fan, which has a third-order stream, and the one fourth-order stream in the catalog (Schmedrick Valles). These volume calculations cannot be directly compared to volume estimates from previous studies (Table A1), which mapped fan and valley area, but which tended to use average estimated thicknesses to determine volume.

100.00

) ) 3 10.00

1st Order 1.00 2nd order 3rd order 4th order 0.10

Fan Deposit Deposit VolumeFan (km 1:1 line

0.01 0.01 0.1 1 10 100 1000 Valley Volume (km3)

Figure 3: Continued on next page 9 b

Figure 3: (a) Fan and valley volume measurements using the segmented plane method. Measurements are color-coded by valley stream order. Error bars indicate the full range of the calculated volumes from all four methods. (b) Box plot displays the mass balance index, which represents the value of the difference between fan volume and valley volume from Method C, divided by the largest fan volume from any of the four methods minus the smallest fan volume from any of the four methods. In two cases, negative values (in which the fan volume is greater than the valley volume) are ignored for the log scale. Values ≤ 1 indicate valley volumes that are comparable to fan volumes within the uncertainty provided by the range of volume estimates, while larger values indicate larger valley volumes compared to fan volumes.

10 Discussion

For the fans that plot below the 1:1 line, trends emerge according to stream order. Valleys with a Strahler order of 1 tend to have fans with only slightly lower volumes than the valley volume. These pairs plot parallel to the 1:1 line, indicating approximately equal fan volumes and valley volumes regardless of valley size. We interpret these pairs to indicate mass preservation. In contrast, valleys with higher Strahler orders increasingly deviate from the slope of the 1:1 line due to increasingly larger valley volumes relative to fan volumes. These trends imply that either fan deposits have been heavily eroded after formation, or that significant amounts of eroded valley sediment were not deposited directly into the fan deposits. To further investigate these observations and determine the extent to which increasing Strahler order correlates with increasingly large differences between fan volume and valley volume, we developed and utilized a mass balance index

(VvalleyC –VfanC)/(Vfan, max – Vfan, min), in which V represents measured sediment volume for fans and eroded sediment volume for valleys. This formula shows how the absolute magnitude of the difference between the fan and valley volumes compares to the range of calculated fan volumes from all methods, which serves as a partial proxy for the uncertainty of the results. The results of this formula using Method C for each fan system were plotted according to stream order (Fig. 3b). This figure shows that systems with a Strahler order of 1 approximately center around 1, while higher Strahler order systems have higher values. Higher values indicate that the difference in volume is beyond the range of measured fan volumes, which implies that either the fan did not capture a significant amount of the eroded valley sediment, or that the fan has been heavily eroded.

11 Our results indicate that fans fed by more integrated valley network systems (Fig. 1c,e) have valley volumes that tend to be much larger than the fan volumes, a tendency that is particularly pronounced for larger valleys (Fig. 3a). The primarily explanation invokes the mechanism of deposition for this fan system. This subset of fans is thought to originate from the more hydrologically active period near the Noachian-Hesperian boundary [Fassett and Head 2008a]. At that time, higher volumes of water would create larger stream discharges, which should be directly proportional to stream order according to Strahler [1957]. In the context of a planet becoming drier through time, stream discharges should also decrease through time, and thus this work’s use of Strahler order appears to be validated. Additionally, Mars’ wetter climate would allow for more extensive valley networks with enough water to hydrodynamically sort the grains during transport. Sorting occurs due to the distinct processes affecting different sediment sizes; smaller grains are transported in suspension, while larger grains move as part of the bedload. The end result is the deposition of more well-sorted fans. Coarser grains would be predominantly deposited near the base of the fan, whereas fines would largely settle in the distal regions. These fines would be more vulnerable to loss via aeolian erosion; thus, this process may partially explain the sediment imbalance in these systems, as erosion would reduce the sediment content of the fans. Alternatively, the volume imbalance may be partially explained by post-depositional erosion [Malin and Edgett 2003, Moore et al. 2003, Jerolmack et al. 2004, Wood 2006, Mangold et al. 2012]. However, these new observations suggest that depositional mechanisms may play a larger role.

Another subset of the results shows that fans fed by poorly-integrated valleys (e.g., Fig. 1b,d), typically with lower stream orders, have valley volumes that are slightly larger than, although the same order of magnitude as, fan volumes (Fig. 3a). This suggests that little landscape-scale denudation has occurred in these systems, and that 12 nearly all of the sediment in these fans is derived from the erosion of the valley itself. Additionally, the trend of these fan systems is approximately parallel to the 1:1 line, which indicates that larger valleys and fans are not preferentially eroded to a greater extent. We proposed that this latter group of approximately mass balanced fans and valleys originates from episodes of hydrologic activity much later in Mars’ history. As the climate grew colder and drier, valley network creation would occur on a more local scale. Under such conditions, with less water in the system, sediment sorting would occur to a lesser degree, resulting in more poorly-sorted fans. These fans would be less vulnerable to the loss of fines. Furthermore, if these fans are younger than the systems in the other group, there has been less time for erosion to take place as well, although this is likely a less significant factor. Only two locations - the Peace Vallis fan and the fan system with the fourth-order valley – had a fan volume that was larger than the valley volume calculated using the segmented plane method (the full suite of volume measurement methods straddle the 1:1 line, Fig. 3a). These cases may be explained by valley infilling, particularly for the fourth-order stream, which appears modified and segmented in places (Fig. A11). Differential preservation of the fan compared to the valley and large amounts of landscape erosion that contributed sediment to the fan are other possible explanations. Landscape denudation is likely less of a factor, since the fan would likely have been eroded as well as the valley. Ultimately, these two pairs fall within the bounds of error for evenly mass-balanced fan systems. Thus, these two fans may simply belong to the category of young, poorly-integrated valley fans.

13 GALE CRATER

These results provide a new framework for interpreting valleys and sedimentary fans in Gale Crater. The fan systems in the southwest part of Gale crater (Fig. 1e) have extensive valley networks, Strahler order values of 2, and low fan volume/valley volume ratios (0.33 for the more southern fan and 0.09 for the northern fan), whereas the Peace Vallis fan system on the north side of the crater (Fig. 1d) has an isolated inlet valley with a fan/valley ratio closer to 1 (1.36). Although the Peace Vallis fan has a higher stream order, Palucis et al. [2016] date the fans in the southwest to the second of three major lake stands in Gale Crater, while the Peace Vallis fan was formed much later under drier conditions after the lake’s existence. These ages are consistent with our interpretation of globally distributed valley/fan pairs that show increased preservation of fan deposits from younger, low-order valleys. Furthermore, the results from this study suggest that the fine-grained sedimentary record is removed from many older, higher stream order fan systems, except in cases where the fine sediment is protected from aeolian erosion by stratigraphically higher coarse facies (e.g., Lewis and Aharonson [2006]). Intriguingly, Curiosity rover investigations of the Peace Vallis fan has identified only distal facies of a delta deposit with no upstream deposits [Grotzinger et al. 2015]. This suggests that the fine fraction of sediments is removed from deposits that morphologically resemble fans from orbit, i.e., the fans investigated in this study, whereas fines-only records like those at Gale Crater may be much more difficult to identify from orbital imagery.

14 Conclusions

Mass balance measurements for a widely-distributed collection of 32 sedimentary fan systems show two major relationships between fan and valley volume: fans fed by low-order valleys have approximately equal fan and valley volumes, while fans fed by high-order valleys are often much smaller. These measurements suggest that age and hydrodynamic sorting may explain these preservation patterns. Noachian-Hesperian-aged high-order valleys may have formed during a wetter climate period, causing sorting by grain-size during transport to be more prevalent, and resulting in more well-sorted fans. Preferential aeolian erosion of fine-grained portions of the fan would partially explain such fan systems’ sediment imbalance. Low-order valleys with fans that are approximately mass balanced are interpreted to have originated from waning or ephemeral hydrologic activity during the Hesperian, or early Amazonian. In drier times and in less integrated valleys, sediment sorting would play less of a role during valley erosion, producing fans with more intermixed grain sizes that are less vulnerable to aeolian erosion. These findings provide a framework for ongoing and future exploration of fan deposits at candidate robotic and human landings sites, such as those at Gale Crater, Holden Crater, and Jezero Crater, by creating predictions of the preservation and spatial locations of fine-grained versus coarse-grained sediments.

15 Appendix

INTRODUCTION

The Appendix for this thesis provides (1) Figures of all the studied fans and valleys; (2) More details of this study’s methodology; (3) A short study of our catalog’s fan lengths vs. fan widths; (4) Complete results from all fan and valley measurement methods; (5) Further analysis of outliers in the results; (6) Analysis of the different volume calculation methods based on their results; (7) Volume calculations of fans and valleys in our catalog compared to other studies; (8) Coordinates and references for our fan catalog; (9) The raw numerical data from our results.

Figure A1: Part 1: CTX-derived DEMs were created from the following stereo-pair images, with the fans located at the following coordinates: Fan 1: P12_005820_1873 and P15_006954_1871 overlain on CTX image P12_005820_1873 at 8.52° N, -48.01° E; Fan 2: B01_009874_1735 and B22_018366_1735 overlain on CTX image B01_009874_1735 at -6.499° N, 141.202° E; Fan 3: P01_001586_1563 and P01_001388_1563 overlain on CTX image P01_001586_1563 at -23.49° N, -12.192° E; Fan 4: P02_001644_1713 and P02_001842_1714 overlain on CTX image P02_001644_1713 at -8.575° N, -159.323° E; Fan 5: D04_028873_1740 and D04_028939_1740 overlain on CTX image D04_028873_1740 at -5.03° N, -147.35° E; Fan 6: G12_022902_1742 and G12_022757_1742 overlain on CTX image G12_022902_1742 at -5.595° N, 140.444° E; Fan 7: P22_009555_1736 and P22_009621_1737 overlain on CTX image P22_009555_1736 at -5.9° N, -149.5° E. Inset and monochrome areas of images derived from THEMIS ~100m/pixel global daytime infrared mosaic.

Figure A1: Part 2: CTX-derived DEMs were created from the following stereo-pair images, with the fans located at the following coordinates: Fan 8: P22_009819_1643 and P22_009674_1644 overlain on CTX image P22_009819_1643 at -15.65° N, -155.2° E; Fan 9: B02_010316_1830 and P22_009683_1830 overlain on CTX image B02_010316_1830 at 3.1° N, - 43.43° E; Fan 10: D05_029018_1741 and D05_029084_1741 overlain on CTX image D05_029018_1741 at -7.96° N, -146.58° E; Fan 11: P22_009718_1511 and P22_009784_1513 overlain on CTX image P22_009718_1511at -27.9° N, 83.1° E. Monochrome area derived from THEMIS ~100m/pixel global daytime infrared mosaic; Fan 12: D02_027825_2144 and D02_028181_2144 overlain on CTX image D02_027825_2144 at 34.3° N, 18.1° E.

Figure A1: Part 3: CTX-derived DEMs were created from the following stereo-pair images, with the fans located at the following coordinates: Fan 13: P19_008602_1883 and P18_008167_1883 overlain on CTX image P19_008602_1883 at 8.5° N, -49.8° E. Inset derived from THEMIS ~100m/pixel global daytime infrared mosaic; Fan 14: G05_020285_1980 and G06_020707_1980 overlain on CTX image G05_020285_1980 at 16.2° N, -53.2° E; Fan 15: G22_026878_1913 and G22_026812_1913 overlain on CTX image G22_026878_1913 at 9.796° N, -46.51° E; Fan 16: G09_021700_1416 and D08_030324_1416 overlain on CTX image G09_021700_1416 at -37.512° N, 158.807° E.

Figure A1: Part 4: Inset and monochrome areas of images derived from THEMIS ~100m/pixel global daytime infrared mosaic. Fan 17: P18_008233_1916 and P20_008879_1915 overlain on CTX image P18_008233_1916 at 11.722° N, -52.925° E; Fan 18: G17_024887_2156 and G18_025309_2156 overlain on CTX image G17_024887_2156 at 35.13° N, -55.54° E; Fan 19: G23_027335_1461 and G21_026346_1461 overlain on CTX image G23_027335_1461 at -33.83° N, 80.91° E; Fan 20: G01_018477_2116 and B22_018055_2117 overlain on CTX image G01_018477_2116 at 31.581° N, -13.129° E; Fan 21: D14_032860_2009 and D15_033071_2009 overlain on CTX image D14_032860_2009 at 20.908° N, 75.511° E; 20 Fan 22: D14_032860_2009 and D15_033071_2009 overlain on CTX image D14_032860_2009 at 20.992° N, 75.582° E; Fan 23: P15_006855_1746 and D15_033082_1746 overlain on CTX image P15_006855_1746 at -5.8° N, 137.3° E; Fan 24: G21_026568_1751 and T01_000881_1752 overlain on CTX image G21_026568_1751 at -5.8° N, 137.3° E; Fan 25: B06_011951_1916 and B07_012373_1915 overlain on CTX image B06_011951_1916 at 12° N, -45° E.

Figure A1: Part 5: CTX-derived DEMs were created from the following stereo-pair images, with the fans located at the following coordinates: Fan 26: G02_019111_1548 and G01_018689_1548 overlain on CTX image G02_019111_1548 at -26.98° N, -34.9° E; Fan 27: G02_019111_1548 and G01_018689_1548 overlain on CTX image G02_019111_1548 at -27.09° N, -34.18° E; Fan 28: P01_001534_1559 and P01_001336_1560 overlain on CTX image P01_001534_1559 at -23.8° N, -33.7° E; Fan 29: P04_002664_1988 and P06_003442_1987 overlain on CTX image P04_002664_1988 at 18.45° N, 77.61° E; Fan 30: P04_002664_1988 and P06_003442_1987 overlain on CTX image P04_002664_1988 at 18.45° N, 77.61° E; Fan 31: D18_034159_1406 and D17_034014_1406 overlain on CTX image D18_034159_1406 at -39.2° N, -103.4° E; Fan 32: G04_019698_1747 and P01_001488_1751 overlain on CTX image G04_019698_1747 at -4.5° N, 137.36° E. Inset and monochrome areas of images derived from THEMIS ~100m/pixel global daytime infrared mosaic. 22 METHODOLOGY

An ArcMap geographic information system (GIS) environment was used for mapping of fans and valleys and for volume calculations. For fans that required multiple Mars Reconnaissance Orbiter Context Camera (CTX) stereo-derived digital elevation models (DEMs) for maximum coverage, the ‘Mosaic to New Raster’ tool served to combine the DEMs into one large DEM with the same cell size throughout. To begin the process of volume calculation after mapping, all four methods used the ‘Extract by Mask’ tool to isolate the elevation data from the DEM for each mapped valley and fan. However, the methods for determining each type of reference surface differed. For the flat plane method (Fig. 2a), points with 10-meter spacing were selected along the fan toe and along the valley rim (excluding the area in which the valley dipped into the crater, if applicable). The elevations for each set of points were averaged in order to obtain an elevation value at which to place the flat plane. Next, the ‘Surface Volume’ tool determined the volume between the reference plane and the extracted valley or fan DEM.

For the segmented, dipping plane method (Fig. 2c), topographic contours with a specified contour interval, typically 50 meters, were generated. In a few cases in which a 50-meter contour interval produced four or fewer lines to constrain a fan, a contour interval of 25 meters was used instead. These contours were traced across each fan and valley using straight lines, in order to increase repeatability. From these trace lines, the ‘Topo to Raster’ tool generated the segmented plane reference surface, which was clipped down to the area of the fan or valley. Finally, the ‘Cut Fill’ tool calculated the volume between the extracted DEM and the reference surface. Both the dipping plane method (Fig. 2b), which is a 1st-order polynomial, and the 2nd-order polynomial method (Fig. 2d) utilize the ‘Trend’ tool to extrapolate a surface from the elevations along the border of the polygon defining the outline of the fan or 23 valley. Like the dipping plane method, these two polynomial methods also use the ‘Cut Fill’ tool to calculate the volume between the extracted DEM and the reference surface. However, for Method D, the 2nd-order polynomial method, additional steps were sometimes required before calculating a surface with the ‘Trend’ tool. Since the fans typically open into craters, the lower reference surface of the fan should characterize this slope, meaning that the lines in the surface should form a concave surface facing inward into the crater. In some cases, though, the contours would curve inward towards the valley, characterizing the surface of the fan instead of the original topography below. To correct this issue, contours were manually extrapolated through the fan based on the surrounding contours in the crater, and then points were added to these spots with the contour elevation manually entered as the points’ elevation. These manual points along the center of the fan were added until they reached a 1:1 ratio with the original elevation points along the boundary of the fan. Together, this new combined set of points fed into ArcMap’s ‘Trend’ tool and enabled the generation of a more accurate lower fan surface for the 2nd-order polynomial (Fig. A2).

Figure A2: Fan 10, created with CTX images D05_029018_1741 and D05_029084_1741 overlain on CTX image D05_029018_1741 at -7.96° N, -146.58° E. (a) Unaltered basal fan surface trend generated with a second- order polynomial. (b) Corrected basal fan surface trend generated with a second-order polynomial. This surface more accurately depicts the expected morphology of the crater wall.

Regardless of the volume calculation method, some fans and valleys required an extra step after the initial volume calculation due to either small sections of the fan or upstream portions of the valley extending beyond the coverage of the CTX DEM. Lower- resolution THEMIS ~100m/pixel global daytime infrared mosaic was used to map out the remaining portions. To calculate the entire volume of a fan with a missing piece, the high-resolution portion of the fan’s volume per area was calculated using the CTX DEM, and that rate was extrapolated to the low-resolution area of fan outside of the CTX DEM to solve for the volume. Similarly, valleys that continued beyond the range of the DEM

25 were measured for the length of their high-resolution and low-resolution portions. The amount of volume per length within the DEM coverage was calculated, and that rate was extrapolated for the length of the low-resolution area to determine its volume. For the final volume, the low-resolution and high-resolution volumes were added together. To objectively sub-divide the fans into groups based on level of integration, the Strahler order for each stream was calculated (Fig. A3) [Strahler 1952].

Figure A3: The methodology for determining stream order is demonstrated above with a sedimentary fan located at 12° N, -45° E. Image shows THEMIS ~100m/pixel global daytime infrared mosaic.

26 FAN LENGTH VS. WIDTH STUDY

Measurements of maximum fan width to maximum fan length yield a highly systematic trend that fits at almost 1:1, indicating that the studied martian fans are consistently elliptical in shape (Fig. A4a,b). While the fans’ shapes appear radial at a glance, one must keep in mind that perfectly radial fans should take the form of a semi- circle and thus would have a maximum length that is half the maximum width.

a b

Figure A4: (a) Plot of maximum fan lengths vs. maximum fan widths, measured for each of the 31 fans in this study. (b) Example measurement of a fan’s maximum length and width. Fan is located at 8.5 °N, -49.8 °E with CTX image P19_008602_1883.

27 COMPLETE VOLUME RESULTS

Above, only one of the four methods, Method C (Fig. 2), is used to interpret the results. However, all four methods produced results, some more accurate than others. Graphs of results from all methods are shown below, followed by a figures explaining the reasoning behind focusing upon only one method’s results in the paper.

Figure A5: Results for the best method, Method C, using a segmented, dipping plane (Fig. 2c). Fan/valley measurements are color-coded by valley stream order. Error bars indicate the full range of the calculated volumes from all four methods. The power law trendlines show decreasing slopes with increasing stream order.

Figure A6: Average results for the four different volume calculation methods (Fig. 2).

100

) ) 3 10

1st Order 1 2nd order 3rd order

0.1 4th order

Fan Deposit Deposit VolumeFan (km 1:1 line

0.01 0.01 0.1 1 10 100 1000 Valley Volume (km3)

Figure A7: Results from Method A (Fig. 2a), which uses a flat reference plane at the average elevation of the valley rim or the crater floor as measured at the fan toe. This method especially tends to overestimate fan volumes.

100

) ) 3 10

1st Order 1 2nd order 3rd order

0.1 4th order

Fan Deposit Deposit VolumeFan (km 1:1 line

0.01 0.01 0.1 1 10 100 1000 Valley Volume (km3)

Figure A8: Results from Method B (Fig. 2b), which uses a reference surface of a dipping plane (i.e., a first-order polynomial) fit to the elevation values at the edge of the fan or the valley rim. This method tends to underestimate fan volumes.

100

) ) 3 10

1st Order 1 2nd order 3rd order

0.1 4th order

Fan Deposit Deposit VolumeFan (km 1:1 line

0.01 0.01 0.1 1 10 100 1000 Valley Volume (km3)

Figure A9: Results from Method D (Fig. 2d), which uses a reference surface of a curved plane fit from a second-order polynomial.

30 In Figure A5, the sole fourth-order stream plots above the 1:1 line, indicating that the current fan volume is larger than the current valley volume. This result does not fit with the trend of valleys with higher stream orders having much greater volumes than their corresponding fans. One possible explanation is that differential erosion may have occurred, with the fan eroding at a slower rate than the infilling of sediment in the valley. This explanation is supported by the segmented, incomplete sections of the valley (Fig. A10).

Figure A10: Sedimentary fan fed by a fourth-order valley at 34.3° N, 18.1° E. Figure is a portion of CTX image D02_027825_2144. The infilling of the valley is evident through the segmented, incomplete nature of the valley.

31 METHODS COMPARISON

Four methods were used to calculate the volumes of the fans, and three were used to calculate the volumes of the valleys. Figure A11, with results plotted by increasing fan volume according to the segmented line method, shows how the segmented line method results generally falls in the middle of the results. The flat plane method tends to produce a maximum fan volume result, the first-order polynomial (P1) method tends to be the minimum result, and the second-order polynomial method has the most unpredictable position. Overall, the valley volume results tend to be more similar between the methods (Fig. A12). However, the flat plane method either appears much higher or lower than the other two methods’ results in several instances. Again, the segmented line method typically falls in the range between the other two methods’ results.

100

) 3 10 Segmented line fan 1 Flat plane fan 0.1 P1 fan P2 fan Fan Volume (km Volume Fan 0.01 0 5 10 15 20 25 30 35 Number of fans with ≤ segmented line volumes

Figure A11: Fan volume results, plotted per fan in order of increasing fan volume (ranked by the segmented line method) and categorized by method. The flat plane often overestimates, producing very high volumes, while the 1st-order polynomial method (P1) tends to slightly underestimate. The 2nd-order polynomial method (P2) produces inconsistent results, and sometimes the resulting surface visually appeared problematic and inaccurate. Volumes calculated with the segmented, dipping plane method tends to fall in between the other methods.

1000

) 3 100

10 Segmented line valley Flat plane valley 1 P1 valley 0.1

Valley Volume (km Volume Valley 0 5 10 15 20 25 30 35 Number of fans with ≤ segmented line volumes

Figure A12: Valley volume results, plotted per location in order of increasing valley volume (ranked by the segmented line method) and categorized by method. The segmented, dipping plane method and the 1st-order polynomial method are generally in accord, with a few exceptions. The flat plane method is also often close to the other values, but sometimes produces volumes much larger or smaller than the other methods.

33 OPEN VS. CLOSED BASINS AND SEDIMENT VOLUME RATIOS We initially hypothesized that many fans could be connected with a putative northern ocean, which may have served as a distal sediment sink for systems with extensive valley networks and high valley volume to fan volume ratios. However, the low number of fans in open basins may belie this hypothesis, as Fig. A13 does not show strong evidence supporting sediment bypass into the northern basin. Similarly, the analysis of the distribution of fans according to the mass balance index (Fig. A13) does not reveal any clear trends. Fans with indexes of 10 or greater might be expected to correspond with open basins in a system dominated by sediment bypass, but such a trend does not exist. Conversely, fans with lower values that indicate closer fan/valley ratios do not solely occur in closed basins, but also have a presence in open basins. If sediment bypass into the northern basin was a dominant process in attached basins, this would not be the case. Overall, these observations reveal a lack of evidence for a northern ocean during the late stage of fan emplacement recorded by these deposits.

Figure A13: The 32 fans analyzed in this study, colored according to the formula (VvalleyC, –VfanC)/(Vfan, max – Vfan, min), a mass balance index which represents the difference of the valley volume and the fan volume, divided by the range of fan volumes from all methods. The blue stars have valley volumes significantly larger than fan volumes. The red stars, with values 1 – 10, have valley volumes only slightly larger than the corresponding fan values. The yellow stars are close enough in value to 1 that they may be a continuation of the approximately mass-balanced category. Stars circled in black are located in open basins, whereas stars transparently circled are located in closed basins.

Tying in the stream orders to this data, we find that lower stream orders dominate for closed basins, and open basins make up a larger proportion of higher stream order fans (Fig. A14). This tendency could support the hypothesis of the northern plains serving as a distal sediment sink for some of the valley systems that are connected. However, given the low number of open basins overall and the lack of clear trends in volume ratios, this idea lacks a preponderance of evidence to support it.

4th

3rd

Open Basin 2nd StreamOrder Closed Basin

1st

0 5 10 15 20 Number of sedimentary fans

Figure A14: The number of sedimentary fans with open vs. closed basins are graphed according to stream order.

36 VOLUME CALCULATIONS FROM OTHER STUDIES

Many of the fans and valleys in this work have been investigated by others, some of whom have calculated volumes for these deposits or systems. Some measurements fall within an order of magnitude of the volumes calculated with our best method, (Method C, using a segmented line), but others do not. There are several potential explanations for these discrepancies. First, many of these papers were published prior to 2006, when the Mars Reconnaissance Orbiter

(MRO) began its primary science phase. The MRO Context Camera and High Resolution Imaging Science Experiment camera have both increased the resolution and availability of stereo image data on Mars. Second, many of these studies approximate thickness more roughly than in this thesis. Kleinhans et al. [2010], for example, calculate an area for each fan and then multiply by an estimate of its average thickness. Additionally, for their stepped fan, Kleinhans et al. [2010] determined the volume by comparing the profile along the delta with the profile along the crater wall adjacent to the delta. As these methods differ from the ones used in this thesis, it follows that different results would be produced. Third, different interpretations regarding the extent of the fans or valley networks could affect the comparison of results between studies. Overall, in volume calculations of fans from other studies (Table A1), the areas of the fans tend to be measured similarly and accurately, but others’ methods tend to estimate the thicknesses of the fans more roughly, occasionally leading to different results for the same fans. Our method appears to generate similar, but more systematic results.

37 Table A1: Volume calculations from other studies Our Best Our Best Fan Valley Fan Fan Valley Name Volume Volume Reference # Volume Volume (km3) (km3) (km3) (km3)

3 Milna Crater 1.8 8.8 - 4 Buhler et al. [2014]

"Stair-stepped" 4 7.4 11 12.8 18 Kleinhans et al. [2010] in Terra Sirenum

13 Tyras 8.5 41 81.88 - Kleinhans et al. [2010]

Liberta Crater 18 0.2 1 1.84 - Salese et al. [2016] fan

28 Eberswalde 5.3 29 6 ~24 Malin and Edgett [2003]

28 Eberswalde 5.3 29 6 - Jerolmack et al. [2004]

28 Eberswalde 5.3 29 13.2 4.3 Moore et al. [2003]

28 Eberswalde 5.3 29 20-30 - Bhattacharya et al. [2005]

28 Eberswalde 5.3 29 5 +/- 1 - Mangold et al. [2012a]

29 Jezero Crater fan 2.4 6 5 - Fassett and Head [2005]

N/A; S Tharsis Mangold and Ansan 31 1.3 69 15 150 region [2006] Gale Crater 36 0.7 0.5 0.4-0.8 0.8 Palucis et al. [2014] Peace Vallis fan

38 Table A2: Fan locations and references Fan Latitude Longitude References # (°N) (°E) Harrison and Grimm [2005]; Di Achille and Hynek [2010]; 1 8.52 -48.01 Goudge et al. [2012] 2 -6.499 141.202 Di Achille and Hynek [2010] Irwin et al. [2007]; Di Achille and Hynek [2010]; Goudge et al. 3 -23.49 -12.192 [2012] Ori et al. [2000]; Di Achille and Hynek [2010]; Goudge et al. 4 -8.575 -159.323 [2015] 5 -5.03 -147.35 Di Achille and Hynek [2010] 6 -5.595 140.444 Di Achille and Hynek [2010] Ori et al. [2000]; Di Achille and Hynek [2010]; Goudge et al. 7 -5.9 -149.5 [2015] Di Achille and Hynek [2010]; Ori et al. [2000]; Goudge et al. 8 -15.65 -155.2 [2012] Di Achille et al. [2007]; Di Achille and Hynek [2010]; Goudge et 9 3.1 -43.43 al. [2015] Cabrol and Grin [2001]; Di Achille and Hynek [2010]; Goudge 10 -7.96 -146.58 et al. [2015] 11 -27.9 83.1 Howard and Moore [2004]; Di Achille and Hynek [2010] Cabrol and Grin [1999]; Di Achille and Hynek [2010]; Goudge 12 34.3 18.1 et al. [2012] Di Achille et al. [2006a]; Di Achille and Hynek [2010]; Goudge 13 8.5 -49.8 et al. [2015] 14 16.2 -53.2 Goudge et al. [2015] 15 9.796 -46.51 Goudge et al. [2015] 16 -37.512 158.807 Goudge et al. [2015] 17 11.722 -52.925 Goudge et al. [2015] 18 35.13 -55.54 Di Achille and Hynek [2010] 19 -33.83 80.91 Goudge et al. [2012] 20 31.581 -13.129 Goudge et al. [2015] 21 20.908 75.511 Goudge et al. [2015] 22 20.992 75.582 Goudge et al. [2015] Cabrol and Grin [2001]; Di Achille and Hynek [2010]; Goudge 23 -5.8 137.3 et al. [2015] Cabrol and Grin [2001]; Di Achille and Hynek [2010]; Goudge 24 -5.8 137.3 et al. [2015] 25 12 -45 Hauber et al. [2009], Di Achille and Hynek [2010] Grant and Parker [2002]; Di Achille and Hynek [2010]; Goudge 26 -26.98 -34.9 et al. [2015] 27 -27.09 -34.18 Goudge et al. [2015] 39 Malin and Edgett [2003]; Di Achille and Hynek [2010]; Goudge 28 -23.8 -33.7 et al. [2015] Fassett and Head [2005]; Di Achille and Hynek [2010]; Goudge 29 18.45 77.61 et al. [2012] Fassett and Head [2005]; Di Achille and Hynek [2010]; Goudge 30 18.45 77.61 et al. [2012] Di Achille and Hynek [2010]; Mangold and Ansan [2006]; 31 -39.2 -103.4 Goudge et al. [2012] 32 -4.5 137.36 Palucis et al. [2014]; Goudge et al. [2015]

Table A2 Continued

0.1

0.2

0.3

0.6

0.1

0.2

0.5

0.3

0.5

0.2

0.5

0.6

0.5

0.2

0.5

2.3

0.6

0.1

0.5

0.1

1.4

0.3

0.7

0.2

0.5

-0.1

0.02

0.01

0.001

0.0004

volume)

method valley valley method

(P2 fan volume) / volume) fan (P2

(segmented plane plane (segmented

0.9

1.3

0.3

1.0

5.3

0.0

5.9

3.2

1.5

7.9

2.2

8.2

0.2

1.3

0.1

0.2

0.8

8.5

0.8

9.7

1.2

5.2

0.4

0.1

2.3

0.6

0.1

7.4

1.8

4.4

0.2

fan

11.3

21.5

2nd-order 2nd-order

polynomial polynomial

(P2) method: method: (P2)

0.2

0.1

0.0

1.9

0.3

0.2

0.3

0.5

0.2

0.1

0.2

0.1

0.3

1.0

0.3

0.1

0.3

0.4

0.1

0.4

0.5

0.2

0.4

0.02

0.05

0.001

valley valley

0.0005

volume

volume / volume

Dippling Dippling

plane fan fan plane

0.3

1.3

0.3

0.7

2.5

0.1

9.1

4.6

2.5

5.9

1.2

0.7

0.2

0.6

0.1

0.3

0.4

3.5

0.3

3.0

0.6

4.5

0.1

0.2

0.6

0.1

5.0

2.2

3.4

0.2

32.6

13.0

0.03

plane plane

Dipping Dipping

method: fan method:

1.8

3.4

2.3

7.9

6.9

9.2

0.9

6.1

0.2

0.3

1.5

0.9

8.6

1.6

0.5

1.4

1.5

9.2

9.7

7.6

63.7

43.9

28.5

16.9

44.7

50.1

24.6

11.8

37.3

59.4

67.5

461.7

plane plane

valley

method: method:

Dipping Dipping

0.5

0.1

0.3

0.5

0.2

0.6

0.3

0.7

1.1

0.2

0.6

0.5

1.6

8.8

9.3

0.8

0.4

0.7

1.4

0.2

0.7

0.2

5.6

1.3

1.9

2.8

0.0

0.03

0.01

volume

/ valley /valley

Flat plane plane Flat

fan volume volume fan

4.2

6.8

0.2

2.5

9.0

1.1

6.3

3.0

0.9

4.3

0.4

3.4

2.0

3.8

0.6

2.4

0.6

0.2

0.5

0.9

1.0

37.0

51.3

14.7

12.9

22.8

10.0

15.6

18.9

12.9

16.8

16.4

28.3

Flat plane plane Flat

method: fan method:

9.0

6.6

4.2

8.8

1.5

8.5

0.2

0.4

0.2

4.7

1.5

1.7

0.8

1.8

2.3

8.6

51.8

43.6

68.2

68.5

41.9

83.5

50.2

18.2

21.2

12.5

23.3

80.8

80.2

13.3

10.0

418.0

valley

method: method:

Flat plane plane Flat

1.4

0.1

0.4

0.1

0.0

0.5

0.3

0.1

0.3

0.4

0.2

0.1

0.3

0.1

0.4

0.5

0.3

0.1

0.3

1.6

0.5

0.1

0.2

0.3

0.0

0.7

0.2

0.4

0.02

0.0005

fan volume / volume fan

valley volume valley

Segmented line Segmented

0.7

1.5

0.2

2.4

1.8

0.1

9.8

4.4

2.2

6.5

1.7

1.0

0.3

1.0

0.1

0.2

0.6

3.3

0.5

6.7

1.0

6.2

0.1

0.3

0.5

0.2

7.9

1.5

3.7

0.3

16.1

method: fan method:

Segmented line Segmented

0.5

2.5

2.9

6.6

8.7

1.0

6.8

0.2

0.4

1.6

4.2

1.9

0.8

1.7

1.8

8.8

9.2

68.6

43.5

29.5

32.4

36.7

50.5

13.3

15.2

15.3

41.3

70.1

70.5

10.9

520.6

method: valley method:

Segmented line Segmented

0.4

0.1

0.6

0.3

0.2

0.4

0.7

0.5

0.3

0.2

0.7

2.9

0.8

0.2

0.4

0.7

0.1

0.4

0.1

0.5

2.0

0.8

0.6

1.1

0.0

0.04

0.004

valley valley

volume

Avg fan fan Avg

volume/ volume/

1.5

2.7

0.2

1.6

4.7

0.3

6.7

4.8

3.8

3.2

0.4

1.8

0.2

1.0

0.9

4.8

0.6

8.8

1.3

8.7

0.3

0.1

0.8

3.7

0.3

9.3

5.5

9.9

0.4

24.3

12.7 17.7

10.8

Avg of all of Avg

fan methods fan

3.8

4.2

3.1

8.1

1.1

7.1

0.2

0.4

1.1

1.3

1.7

0.7

1.6

1.9

9.0

8.9

61.4

43.7

42.0

39.2

41.1

61.4

29.4

10.9

16.0

12.3

27.8

12.0

70.1

72.7

11.1

466.8

valley valley

methods

Avg of all of Avg

Order

Stream Stream

8s Fan # Fan

41 References

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45 Vita

Katherine Rose Shover was born in Indianapolis, Indiana, USA. She graduated from Roncalli High School in 2010 and went on to attend DePauw University in Greencastle, Indiana, where she earned a Bachelor’s Degree in geology with minors in computer science and political science in 2014. She completed field camp through

Indiana University in the summer of 2014. In May 2016, she completed her M. S. in Geological Sciences at the University of Texas at Austin.

Permanent email address: [email protected] This thesis was typed by the author.