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FRACTURE NETWORKS ON : Preservation of Surface and Subsurface Environments at

Student Author Mentor

Phoebe Kinzelman is a rising Briony Horgan is an assistant senior at Purdue University professor in the Department majoring in planetary science of Earth, Atmospheric, and with a minor in global liberal Planetary Sciences at Purdue arts studies. She is especially University. She received her BS interested in planetary geology in physics from Oregon State and public science policy and University in 2005 and her worked as a space policy intern PhD in astronomy and space at the National Academy of Sciences in Washington, sciences from Cornell University in 2010, then was D.C., for the summer of 2019. Kinzelman currently an Exploration Postdoctoral Fellow at Arizona State works as an ambassador for both the College of University until joining EAPS in 2014. Horgan’s Science and the Department of Earth, Atmospheric, research program uses data from NASA satellites and and Planetary Sciences (EAPS) in addition to rovers, along with lab and fieldwork back on Earth, undergraduate research and enjoys rock climbing in to understand the surface processes that have shaped her spare time. In the future, she hopes to become an Mars and the moon. She is particularly interested astronaut on Mars. in using mineralogy to investigate weathering and past surface environments on Mars as well as volcanic, sedimentary, and impact processes on both planets. Horgan is a participating scientist on NASA’s rover mission and a coinvestigator on NASA’s upcoming rover mission, the first step toward the Mars sample return mission.

42 Journal of Purdue Undergraduate Research: Volume 9, Fall 2019 http://dx.doi.org/https://doi.org/10.5703/1288284316931 Fracture Networks on Mars 43 typically exists in sedimentary rocks 2+ mineral appears layer the at areas of 2+ INTRODUCTION Global MOLA map of Mars with Mawrth Vallis Vallis 1. Global MOLA map of Mars with Mawrth Figure star. a white by denoted Modern Mars and hyperarid, is cold there but are owing water, pastabundant signs fl of physical channels,ow lake and assuch deltas, valleys, outfl uvial activity is sediments. fl One sign of such channelow that cuts through Mawrth an outfl Vallis, the terrains ancient most of some Mars. on This kind channel of formation occurred likely most ooding during the late era due to rare fl As in shown Carr & Head, 2010). episodes (e.g., the channelFigure is situated 1, the on dichotomy boundary between the Martian highlands and The 2008). et al., (Bishop 20°W ~25°N, at lowlands area around Mawrth a thick is composed of Vallis sedimentary light-toned sequence of dating layers billion billion to 4.0 from the Noachian era (~3.7 Orbital spectroscopyyears has ago). that shown these rich, are layers with and Al-phyllosilicates smectites Fe/Mg hydrated top on of layered silica a partially by and overlaid eroded dark capping the clay layered of Most unit (Loizeau 2015). et al., deposits in the area 200 are meters over thick. The appearclays to be inconsistent with hydrothermal activity groundwater, or and regional extent and uence suggest a surface topographiclack of infl weathering origin (Noe the Dobrea clays et al., for This and Al-phyllosilicates layering Fe/Mg of 2010). smectites can be attributed to a semiarid climate and weathering rain by that produced the seen paleosols in the area today Loizeau, (Carter, Poulet, Mangold, & Bibring, 2015). These Martian ancient rocks formed likely were in aqueous environments ancient for that habitable were showed 2013) (2008, et al. Bishop microbial life. that an Fe transition from smectites. to Al-phyllosilicates Fe/Mg On Earth, Fe , 42–48. Keywords Mars, fractures,Mawrth Vallis, , andAl-phyllosilicates hydrated silica, Fe/Mg uvial activity smectites, fl https://doi.org/10.5703/1288284316931 Abstract channel ow on Mars Mawrth is an outfl Vallis most that cuts through the planet’s of some erent terrains,ancient contain which many diff types fractures. of mission The rover ExoMars will biosignatures search for Mars, on and this was proposed the site two as of one nal candidate A landing for rover. sitesthe fi evidence that is any object shows past present or Fractureof life. networks are a high priority the because mission for they uid might contain minerals precipitated fl by interaction, and these minerals trap could and preserve biosignatures, critical our for understanding processes. ancient of In this seek to determine we project, the distribution and origin large fractures of in the Mawrth Mission-Planning The region. Java Vallis and Sensing Remote Analysis (JMARS) for program and satellite images from the High ImagingResolution Science Experiment (HiRISE) both orbiter were used to map fractures Mawrth at Based similar on Vallis. fractures Earth, on interpreted have we that theall large fractures of formed due to water a rectangular but loss, shape suggests that the fractures formed rocks when contracted the at surface, while curvilinear fractures formed in subaqueous sediments. After contraction, lled by precipitatedin the fractures fi were minerals, causing them to appear bright. These uid fractures Mars on sort some fl imply of precipitatedand mineralsow, in the fractures fl preservemay the evidence environment of and lifeancient that existed once in that area. Fracture networks on Kinzelman, (2019). P. Mars: Preservation surface of and subsurface environments Mawrth at Journal of Vallis. 9 Research, Undergraduate Purdue because it precipitated out of reducing fluids (Bishop in the clay layers at Mawrth are a high priority for et al., 2008). The presence of strong redox gradients this mission because they might contain minerals in the subsurface is a key discovery in the study of precipitated by fluid interaction, and these minerals the history of Mawrth Vallis, as it could indicate a could trap and preserve biosignatures, critical habitable environment with significant microbial for our understanding of ancient processes and energy sources (Horgan, Rice, Farrand, Sheldon, & environmental conditions of the planet. However, no Bishop, 2015). In addition, on Earth, organic material map currently exists of the distribution of fractures and/or microbes are often necessary to reduce Fe, in the proposed Mawrth Vallis landing ellipse for the and paleosols have a high preservation potential ExoMars rover. for this kind of material (Hays et al., 2017). Thus, the clays at Mawrth Vallis have the potential of The objective of our study was to map the preserving biosignatures from ancient microbial life. distribution and morphologic properties of fractures within a region of Mawrth Vallis as outlined by two The clay-rich terrain in Mawrth Vallis also hosts a potential landing ellipses for the ExoMars rover. One diverse suite of large fractures and fracture networks, ellipse was centered at 341.567E, 22.372N and the some of which are further indications of subsurface other at 342.055E, 22.156N. We used HiRISE orbital fluid flow in the area. Loizeau et al. (2015) identified imagery to look for fractures and fracture patterns, four different types of fractures at Mawrth Vallis: and the physical features of each fracture were small and thin, thick, short, and parallel fractures. analyzed once it was recorded. We identified three According to Loizeau et al. (2015), fracturing of the key fracture morphologies within the mapping area: clay unit occurred after the clay had lithified into rectangular, irregular (linear and curvilinear), and solid rock. This process broke the newly formed rock halo-bounded fractures. into blocks, and then groundwater flowed through the fractures and left behind precipitated minerals. We hypothesize that the variety of fracture “Halo-bounded” fractures (a subset of thick and short morphologies present at Mawrth Vallis represents fractures) were created in this way. Loizeau et al. different formation environments, and any (2015) also found that the Al clay unit holds the most precipitated minerals in the fractures could be potential for preserving biosignatures because it is accessed by a future rover mission such as ExoMars protectively covered by the capping unit and has not in the search for preserved Martian biosignatures. been subject to erosional surface processes. Thus, the earlier discovery of at least two watery episodes MATERIALS AND METHODS (surface water that lithified the clay, then subsurface water that filled fractures with precipitated minerals) This research project began in July 2018 and leaves the possibility of multiple areas for trapped eventually extended into the fall semester. Three biosignatures. However, the depth and environment undergraduate students (Phoebe Kinzelman, (surface vs. subsurface) of the large fractures in the Jonathan Forss, and Madison Van Buskirk) along Mawrth Vallis region are not well understood. with faculty adviser Professor Briony Horgan were contributors to this project. Each student was The ExoMars program is a European Space Agency responsible for mapping a third of the total outlined project tasked with investigating the possibility of landing ellipses and recording all mapped data into a past microbial . ExoMars consists of fracture database. The JMARS software application the Schiaparelli lander, a (both was used to view images, create maps, and build launched in 2016), and a rover that will launch in the fracture database. JMARS is an open-source 2020. The Trace Gas Orbiter will analyze gases geospatial information system created at Arizona in the Martian atmosphere, and Schiaparelli was State University and designed to assist researchers meant to test landing sequences on the planet but has with mission planning and data analysis on the since crashed. The ExoMars rover, now colloquially surface of other planets. The information system named after Rosalind Franklin, will visit different contains a wealth of Martian orbiter data and maps sites that are important to the investigation for use in a variety of scientific research projects. The of biological activity on Mars. The rover will HiRISE camera was primarily used to search for and eventually search for biosignatures on the planet, map fractures (McEwen et al., 2007). HiRISE is one and Mawrth Vallis was proposed as one of the two of three cameras on NASA’s Mars Reconnaissance final candidate landing sites for the rover, the other Orbiter. Images collected by HiRISE are acquired being . A biosignature is any object that with a resolution of up to 25 cm per pixel and are shows evidence of past or present life (e.g., Hays et used to analyze Martian geology and mineralogy in al., 2017). Fracture networks such as those found the visible light spectrum.

44 Journal of Purdue Undergraduate Research: Volume 9, Fall 2019 Fracture Networks on Mars 45 Completed fracture distribution map. Grids that Grids that distribution fracture map. 3. Completed Figure possible , outlined in are fractures definite have in red. and no fractures in yellow, fractures Each student was assigned one-third the area of the by smallercovered landing ellipses in order to map the distribution fracturesof in the area. The latitude/longitude grid was used each layer student by her histo or split mapping area into grid 1-km squares based the on desired HiRISE image resolution, and each student grids 700 mapped over on well the ellipses. Each grid square was automatically assigned latitude and longitude coordinates within the program. First, individual HiRISE images that corresponded to the grid square interest of were loaded and using cataloged their ID The number. search was limited to bright outcrops within the grids1-km so that only the fractures obvious were Fractureslogged. in logged the were database as “present” with with 2, “possible” and the number 1, present”“not Any with fractures 3. the at found mapped, were resolution and the 65,536- 32,768-ppd ppd was used zoom resolution sparingly in instances was difficultwhere it to ascertainwhether feature a was a fracture Fractures not. or that appeared in two grid squares mapped were as present in both, and any extra information the about surrounding terrain was also noted. and In red box addition, green,yellow, shapes corresponding to grid squares with present, and present not fractures,possible, respectively, thenwere added so the entire mapping area be could analyzed dispersion overall for trends (Figure 3). Once a fracture was mapped as either “present” was analyzed it morphology, for “possible,” or (rectangular) irregular or including polygonal (linear/curvilinear) long), or shape, size (short density of unit (reddish-brown, clay blue), of color fractures and brightness. (high, moderate, low), Numbers also were assigned the presence a to log of All present). 3 = not = present, 2 = possible, (1 halo JMARS comes with three preloaded map data sets: a latitude/longitude grid, and a nomenclature layer, a Mars Orbiter Laser Altimeter colorized (MOLA) first nomenclaturehid the We shadedlayer relief. and added a map bar scale in order to best see our mapping area. Our base map was a combination data elevation made partially MOLA-colored of transparent the THEMIS over Infrared Day 100- that a map captures layer Mosaic, Global meter/pixel thermal images from the Thermal Imaging Emission System board on the Daytime Mars Odysseyorbiter. thermal images geological are of to slopes sensitive landforms, so the is because helpful mosaic it sharpens We of Mars.effectively maps elevation then began importingour for shapefiles project. Several landingwere ellipse shapefiles created and Christoph Dr. by Universität provided Gross Freie of Berlin, including two ellipses different with slightly km and 135.6 orientations and centers. Large (111.4 versions km long) and 122.6 and small (90.7 long) each ellipse correspondingof versus higher to lower landing but probabilities of locations available, were deadlinein order completion to make the November prior to the the landing ExoMars workshop, site mapping to area the smaller was moved ellipses. Another was dedicated map layer to the mapping grid, into was split which equal thirds and color- coded to ensure that each student had a unique section to analyze, as in shown Figure 2. Finally, remote sensing data in light spectrum the visible from the HiRISE orbiter was imported as a HiRISE Full Stamps in orderlayer to find fractures.To ensure that fracture mapping remained consistent, pixels the was mapping restricted resolution to 32,768 per degree (ppd) occasionally or zoomed into 65,536 ppd to verify interpretations. Map of the proposed ExoMars landing ellipses landing ellipses ExoMars 2. Map of the proposed Figure the divided and in white) here (shown Vallis Mawrthfor THEMIS and shaded relief with the MOLA mapping area, turned on. IR 100m Global Mosaic layers Day Figure 4. Example of a rectangular fracture network, shown Figure 5. Example of an irregular fracture, shown here at here at 65,536 ppd and outlined in a white box. 65,536 ppd and outlined in a white box.

Figure 6. Example of possible halo-bounded fractures, shown here at 65,536 ppd and outlined in white boxes.

46 Journal of Purdue Undergraduate Research: Volume 9, Fall 2019 Fracture Networks on Mars 47 DISCUSSION AND CONCLUSION AND DISCUSSION The results our fracture of classifications at Mawrth us to allow infer kind what formationVallis of environments been different must present have for fracture Rectangular sequences. formation fractures imply contraction(tessellations) at the surface, infill by or followed mineral precipitation in the Onjoints. Earth, this occurs in sedimentary rocks a varietyof grain of sizes due to wetting and drying salts carbonates. or and often involves cycles Mudcracks as such those in shown Figure 8 are a the Therefore, this surfacesubset of category. origin the rectangularof fractures Mawrth at is consistent with their in location the uppermost section at or curvilinear thethe However, stratigraphy. top of fractures suggest may subsurface contraction without drying, usually in saturated subaqueous clay-rich sediments. This morphology is also thought to form during subaqueous compaction and subsequent Cartwright, dewatering (e.g., 2003). James, & Bolton, a subsurfaceTherefore, and subaqueous origin the of curvilinear fractures Mawrth at is consistent with their in location the sediments. Fe/Mg-smectite Knowing theformation different environments that existed Mawrth at is extremely in helpful our Vallis biosignaturessearch for Mars. on As stated in our introduction, will the rover launch ExoMars in 2020 and investigate its finalbiosignatures.landing for site Mawrth was the on short landing list Vallis of site Stratigraphic column of Mawrth Vallis (adapted (adapted Vallis of Mawrth column 7. Stratigraphic Figure 2015). et al., Loizeau from RESULTS The last step in cataloging fractures was comparing fracturesthe of morphologies to terrestrial analogs. Earth and Mars undergo similar surface processes, and thesimilarities between planets simpler make it to determine something how formed Mars on because formed likely it the Earth. on same way thisUsing method, can constrain we the origin of fracture. mapped each One difficulty of wasthis project the inconsistency in fracture analysis that arose from using multiple mappers. Fracture analysis had a tendency to vary from student to student, overlapping so a few regions the on margins each area of analyzed were theby group. Afterward each characteristic of the fractures in logged these shared areas was compared, and any differences in individual analysis edited were to ensure future consistency of fracture mapping. of the above characteristics the identified above of positively of fractures then in were logged a shapefile database JMARS. within Bright fractures, easier were to which identify using remote sensing methods, abundant were in the southern and central parts the two ellipses of less concentrated were but in the far northern areas. The differences in typesof fracturesidentified are their a result likely most of occurrence in different stratigraphy, with rectangularparts the area’s of fractures the embedded capping just below unit, bright fractures in the boundary between smectites, andAl-phyllosilicates Fe/Mg halo- bounded fractures and in smectite the Fe/Mg layer, thin fractures throughout, as in shown Figure 7 from(adapted Loizeau 2015). et al., The database each on compiled identified we fracture properties morphological included a list of that assisted in our namingof and classification different typesof fractures.Figure shown As in named we 4, rectangular fractures their for shape and classified themfractures as polygonal because they often most appear in repeating patterns. By contrast, irregular fractures as such in Figure 5 are any patterning.those that show do not Both linear and curvilinear fractures fall under the irregular fracture with linear category, fractures appearing as straight lines and curvilinear fractures appearing these any fracture of curves.as slight Finally, types appearcould halo-bounded, partially surrounded by a bright halo-like ring as in Figure 6. ACKNOWLEDGMENTS

I would like to thank Professor Briony Horgan, our project mentor, as well as Dr. Christoph Gross and Francois Poulet for their contributions to this project.

REFERENCES Bishop, J. L., et al. (2008). Phyllosilicate diversity and past aqueous activity revealed at Mawrth Vallis, Mars. Sci- ence, 321(5), 830. doi:10.1126/science.1159699 Bishop, J. L., Loizeau, D., McKeown, N. K., Saper, L., Dyar, M. D., Des Marais, D. J., . . . Murchie, S. L. (2013). What the ancient phyllosilicates at Mawrth Vallis can tell us about possible habitability on early Mars. Planetary & Space Science, 86, 130–149. doi:10.1016/j.pss.2013.05.006 Carr, M. H., & Head, J. W. (2010). Geologic history of Mars. Earth & Planetary Science Letters, 294(3), 185–203. Figure 8. Example of mudcracks in Death , California, doi:10.1016/j.epsl.2009.06.042 a terrestrial analog to rectangular fractures at Mawrth Vallis Carter, J., Loizeau, D., Mangold, N., Poulet, F., & Bibring, (photograph by Michael C. Rygel, distributed under a CC J.- P. (2015). Widespread surface weathering on early BY-SA 3.0 license). Mars: A case for a warmer and wetter climate. Icarus, 248, 373–382. doi:10.1016/j.icarus.2014.11.011 Cartwright, J., James, D., & Bolton, A. (2003). The genesis of polygonal fault systems: A review. Journal of the candidates for this project because of its mineral- Geological Society, 216(1), 223–243. doi:10.1144/GSL. filled fractures, but the distribution of different types SP.2003.216.01.15 of fractures in the area was unknown, as were the Hays, L. E., Graham, H. V., Des Marais, D. J., Hausrath, E. M., kinds of environments that existed to create fractures Horgan, B., McCollom, T. M., . . . Lynch, K. L. (2017). and preserve biosignatures in the first place. In order Biosignature preservation and detection in Mars analog environments. Astrobiology, 17(4), 363–400. doi:10.1089/ to answer these uncertainties, we produced a map of ast.2016.1627 fractures found in two potential landing ellipses as Horgan, B., Rice, M. S., Farrand, W. H., Sheldon, N. D., & well as a final hypothesis on what kinds of formation Bishop, J. L. (2015). Possible microbial energy pathways environments existed in that area. We hypothesize from iron and sulfur redox gradients at Mawrth Vallis that rectangular fractures at the top of the layering and Crater, Mars, Astrobiology Science Conference, #7463. sequence formed due to desiccation in a subaerial Loizeau, D., Mangold, N., Poulet, F., Bibring, J.- P., Bishop, environment and that curvilinear and irregular J. L., Michalski, J., & Quantin, C. (2015). History of the fractures in Fe/Mg-smectites formed during burial clay-rich unit at Mawrth Vallis, Mars: High-resolution and dewatering of subaqueous sediments. If present, mapping of a candidate landing site. Journal of Geophys- precipitated minerals in shallower rectangular ical Research Planets, 120(1), 1820–1846. doi:10.1002/ 2015JE004894 fractures may preserve fluids and biosignatures McEwen, A. S., et al. (2007). Mars Reconnaissance Orbiter’s from surface environments. This may also support High Resolution Imaging Science Experiment (HiRISE). the proposed subaqueous mineral deposition of Journal of Geophysical Research, 112(E). doi:10.1029/ these layers. Finally, precipitated minerals in deeper 2005JE002605 curvilinear fractures may preserve fluids and Noe Dobrea, E. Z., et al. (2010). Mineralogy and stratigraphy of phyllosilicate-bearing and dark mantling units in the biosignatures from subsurface environments. greater Mawrth Vallis/west area: Con- straints on geological origin. Journal of Geophysical Though Oxia Planum has been chosen as the final Research, 115(E). doi:10.1029/2009JE003351 landing site for the ExoMars rover, further analysis of the filled fractures at Mawrth Vallis will prove critical to our understanding of ancient fluvial processes, potential biological processes, and environmental conditions of Mars.

48 Journal of Purdue Undergraduate Research: Volume 9, Fall 2019