A Comparison and Analog-Based Analysis of Sinuous Channels on The

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KECK GEOLOGY CONSORTIUM

PROCEEDINGS OF THE TWENTY-FIFTH ANNUAL KECK RESEARCH SYMPOSIUM IN GEOLOGY

April 2012 Amherst College, Amherst, MA

Dr. Robert J. Varga, Editor Director, Keck Geology Consortium Pomona College

Dr. Tekla Harms Symposium Convenor Amherst College

Carol Morgan Keck Geology Consortium Administrative Assistant

Diane Kadyk Symposium Proceedings Layout & Design Department of Earth & Environment Franklin & Marshall College

Keck Geology Consortium Geology Department, Pomona College 185 E. 6th St., Claremont, CA 91711 (909) 607-0651, [email protected], keckgeology.org

ISSN# 1528-7491

The Consortium Colleges The National Science Foundation ExxonMobil Corporation

KECK GEOLOGY CONSORTIUM PROCEEDINGS OF THE TWENTY-FIFTH ANNUAL KECK RESEARCH SYMPOSIUM IN GEOLOGY ISSN# 1528-7491

April 2012

Robert J. Varga Keck Geology Consortium Diane Kadyk Editor and Keck Director Pomona College Proceedings Layout & Design Pomona College 185 E 6th St., Claremont, CA Franklin & Marshall College 91711

Keck Geology Consortium Member Institutions: Amherst College, Beloit College, Carleton College, Colgate University, The College of Wooster, The Colorado College, Franklin & Marshall College, Macalester College, Mt Holyoke College, Oberlin College, Pomona College, Smith College, Trinity University, Union College, Washington & Lee University, Wesleyan University, Whitman College, Williams College

2011-2012 PROJECTS

TECTONIC EVOLUTION OF THE CHUGACH-PRINCE WILLIAM TERRANE, SOUTH-CENTRAL ALASKA Faculty: JOHN GARVER, Union College, Cameron Davidson, Carleton College Students: EMILY JOHNSON, Whitman College, BENJAMIN CARLSON, Union College, LUCY MINER, Macalester College, STEVEN ESPINOSA, University of Texas-El Paso, HANNAH HILBERT-WOLF, Carleton College, SARAH OLIVAS, University of Texas-El Paso.

ORIGINS OF SINUOUS AND BRAIDED CHANNELS ON ASCRAEUS MONS, MARS Faculty: ANDREW DE WET, Franklin & Marshall College, JAKE BLEACHER, NASA-GSFC, BRENT GARRY, Smithsonian Students: JULIA SIGNORELLA, Franklin & Marshall College, ANDREW COLLINS, The College of Wooster, ZACHARY SCHIERL, Whitman College.

TROPICAL HOLOCENE CLIMATIC INSIGHTS FROM RECORDS OF VARIABILITY IN ANDEAN PALEOGLACIERS Faculty: DONALD RODBELL, Union College, NATHAN STANSELL, Byrd Polar Research Center Students: CHRISTOPHER SEDLAK, Ohio State University, SASHA ROTHENBERG, Union College, EMMA CORONADO, St. Lawrence University, JESSICA TREANTON, Colorado College.

EOCENE TECTONIC EVOLUTION OF THE TETON-ABSAROKA RANGES, WYOMING Faculty: JOHN CRADDOCK. Macalester College, DAVE MALONE. Illinois State University Students: ANDREW KELLY, Amherst College, KATHRYN SCHROEDER, Illinois State University, MAREN MATHISEN, Augustana College, ALISON MACNAMEE, Colgate University, STUART KENDERES, Western Kentucky University, BEN KRASUSHAAR

INTERDISCIPLINARY STUDIES IN THE CRITICAL ZONE, BOULDER CREEK CATCHMENT, FRONT RANGE, COLORADO Faculty: DAVID DETHIER, Williams College Students: JAMES WINKLER, University of Connecticut, SARAH BEGANSKAS, Amherst College, ALEXANDRA HORNE, Mt. Holyoke College

DEPTH-RELATED PATTERNS OF BIOEROSION: ST. JOHN, U.S. VIRGIN ISLANDS Faculty: DENNY HUBBARD and KARLA PARSONS-HUBBARD, Oberlin College Students: ELIZABETH WHITCHER, Oberlin College, JOHNATHAN ROGERS, University of Wisconsin-Oshkosh, WILLIAM BENSON, Washington & Lee University, CONOR NEAL, Franklin & Marshall College, CORNELIA CLARK, Pomona College, CLAIRE McELROY, Otterbein College.

THE HRAFNFJORDUR CENTRAL VOLCANO, NORTHWESTERN ICELAND Faculty: BRENNAN JORDAN, University of South Dakota, MEAGEN POLLOCK, The College of Wooster Students: KATHRYN KUMAMOTO, Williams College, EMILY CARBONE, Smith College, ERICA WINELAND- THOMSON, Colorado College, THAD STODDARD, University of South Dakota, NINA WHITNEY, Carleton College, KATHARINE, SCHLEICH, The College of Wooster.

SEDIMENT DYNAMICS OF THE LOWER CONNECTICUT RIVER Faculty: SUZANNE O’CONNELL and PETER PATTON, Wesleyan University Students: MICHAEL CUTTLER, Boston College, ELIZABETH GEORGE, Washington & Lee University, JONATHON SCHNEYER, University of Massaschusetts-Amherst, TIRZAH ABBOTT, Beloit College, DANIELLE MARTIN, Wesleyan University, HANNAH BLATCHFORD, Beloit College.

ANATOMY OF A MID-CRUSTAL SUTURE: PETROLOGY OF THE CENTRAL METASEDIMENTARY BELT BOUNDARY THRUST ZONE, GRENVILLE PROVINCE, ONTARIO Faculty: WILLIAM PECK, Colgate University, STEVE DUNN, Mount Holyoke College, MICHELLE MARKLEY, Mount Holyoke College Students: KENJO AGUSTSSON, California Polytechnic State University, BO MONTANYE, Colgate University, NAOMI BARSHI, Smith College, CALLIE SENDEK, Pomona College, CALVIN MAKO, University of Maine, Orono, ABIGAIL MONREAL, University of Texas-El Paso, EDWARD MARSHALL, Earlham College, NEVA FOWLER-GERACE, Oberlin College, JACQUELYNE NESBIT, Princeton University.

Funding Provided by: Keck Geology Consortium Member Institutions The National Science Foundation Grant NSF-REU 1005122 ExxonMobil Corporation Keck Geology Consortium: Projects 2011-2012 Short Contributions— Ascraeus Mons, Mars Project

ORIGINS OF SINUOUS AND BRAIDED CHANNELS ON ASCRAEUS MONS, MARS Project Faculty: ANDREW DE WET, Franklin & Marshall College, JAKE BLEACHER, NASA-GSFC, BRENT GARRY, Smithsonian

A COMPARISON AND ANALOG-BASED ANALYSIS OF SINUOUS CHANNELS ON THE RIFT APRONS OF ASCRAEUS MONS AND PAVONIS MONS VOLCANOES, MARS ANDREW COLLINS, The College of Wooster Research Advisors: Andy De Wet, Jake Bleacher, & Shelley Judge

ORIGIN OF SINUOUS CHANNELS ON THE SW APRON OF ASCRAEUS MONS AND THE SURROUNDING PLAINS, MARS ZACHARY SCHIERL, Whitman College Research Advisor: Patrick Spencer

VOLCANIC OR FLUVIAL CHANNELS ON THE SOUTH-EAST RIFT APRON OF ASCREAUS MONS JULIA SIGNORELA, Franklin and Marshall College Research Advisor: Andy De Wet

Keck Geology Consortium Pomona College 185 E. 6th St., Claremont, CA 91711 Keckgeology.org

25th Annual Keck Symposium: 2012 Amherst College, Amherst, MA A COMPARISON AND ANALOG-BASED ANALYSIS OF SINUOUS CHANNELS ON THE RIFT APRONS OF ASCRAEUS MONS AND PAVONIS MONS VOLCANOES, MARS

Andrew collins, The College of Wooster Research Advisors: Andy deWet, Jake Bleacher, and Shelley Judge INTRODUCTION We first mapped features, including sinuous channels, depressions, pits, impact craters, vents, and flows, on The origin of sinuous channels on the flanks of the the southwest rift apron of Ascraeus. I then mapped Tharsis volcanoes on Mars is debated among plan- similar features on the southwest rift apron of Pavo- etary scientists. Some argue a volcanic genesis nis. Over the course of study, maps were updated to (Bleacher et al., 2010) while others have suggested include flow edges, flow channels, flow centerlines, a fluvial basis (Murray et al., 2010; Mouginis-Mark scarps, and lava tubes. Features of both of these vol- and Christensen, 2005). The majority of the studies canoes were visually compared and, using 3D Analyst thus far have focused on channels on the rift apron of in ArcGIS and digital elevation models from MOLA Ascraeus Mons. Here, I broadly examine the chan- data, their dimensions and profiles were analyzed. nels on the rift apron of Pavonis Mons and compare them with those studied channels around Ascraeus. I Over the summer, as part of the Keck Mars research compare the morphologies of features from both of group, I conducted field work on Hawai’i, examining these volcanoes with similar features of known volca- leveed channels in the recent (1969-1974) Muliwai nic origin on the island of Hawai’i. a Pele flow associated with the Mauna Ulu satellite shield, the skylights and collapse tubes in the 1907 I propose that the morphologies between these two and 1859 Mauna Loa flows, the 1801 Hualalai flow, volcanoes in the Tharsis province are very similar the Pauahi crater, and other features. We used field and were likely formed by comparable processes, observations, ArcGIS, and Google Earth to quantita- as previous authors have suggested (Bleacher et al., tively and qualitatively compare these features with 2007). Although the morphologies of many of the some of the morphologies found on Mars and attempt channels around these volcanoes show some parallels to evaluate their origins. to terrestrial fluvial systems, these morphologies can also be formed by volcanic processes. The context of RESULTS these features suggests that volcanic processes were the more likely cause of these channels. The channels on the southwest apron of Ascraeus are highly variable in their morphology and sinuosity. RESEARCH METHODS They can vary in length from 2 km (and potentially smaller, but the data resolution does not allow us to Using ArcGIS, I created a composite photographic differentiate such small features) to thousands of kilo- base layer. This was composed of low-resolution meters. Over the course of our research, we found at infrared images from the Thermal Emission Imaging least one that did not seem to have an end. It periodi- System (THEMIS) aboard the Mars Odyssey Orbiter. cally graded out and reappeared a short distance later. Over this base layer, I georeferenced and embedded Most channels do not have this characteristic, but high-resolution images both from THEMIS (Chris- those that do provide evidence for the idea that many tensen et al., 2004) and the Mars Express Orbiter of the shorter channels may have been longer but mission’s High Resolution Stereo Camera (HRSC; were filled in over time, either by windblown dust or Jaumann et al., 2007). Once I had a sufficiently high- by subsequent volcanic processes. resolution mosaic, we began mapping. Streamlined islands appear in multiple sinuous 61 25th Annual Keck Symposium: 2012 Amherst College, Amherst, MA channels. Though they are best exemplified in the The observed sinuous channels on Ascraeus Mons ones identified by Bleacher et al. (2010), they can do not show evidence of levees or sloped walls. The be found in other locations as well. They are typi- channel walls are mostly steep-sided hanging walls, cally no longer than 2 km and are tear-drop-shaped, and the channels, instead of being contained within with the point (if it is distinguishable) facing down levees, are generally embayed by younger, flat-lying slope, in the direction of the surrounding flow. Many surfaces without any form of embankment or levees. channels with streamlined islands also contain some MOLA resolution is not sufficient to determine depth degree of anastamosing (Fig. 1). In some instances, of the channels, and THEMIS data collection is such the branches never return to a single path, and in oth- that we cannot determine the exact angle of the sun ers, multiple braids come into contact with each other and find the depth trigonometrically. However, us- again at various intervals. This may relate to the ing other shadows as relative markers, it appears as previously mentioned problem of disappearing and though most of the channels have a width:depth ratio reappearing channels. These braided systems may be of at least 1:1, and are therefore potentially represen- partially filled, and we simply cannot see them rejoin. tative of more than just surface processes.

The Pavonis rift apron shows sinuous channels, linear depressions, pits, impact craters, and various flow features similar to those found on Ascraeus. The relationships between the features are similar and equally variable. We see sinuous channels entering and emerging from linear depressions, depressions and channels following and/or emerging from pits or pit chains, and branching sinuous channels with hanging walls.

There are a few principal differences between our observations of Ascraeus Mons and my observations of Pavonis Mons. Sinuous channels with hanging walls on Pavonis occur both with flat-lying margins, as on Ascraeus, and with sloped embankments (Fig. 2). The channels become thinner in width as they move down slope, and thus these embankments are interpreted as overflow deposits of some sort. There are fewer braided channels, but many branching instances where the branches simply do not return to a single channel. Tear-drop-shaped streamlined islands, an important element of evidence, can be found both in un-leveed sinuous channels and also, unlike on Ascraeus, in leveed channels.

I examined recently formed leveed channels in the 1907 Mauna Loa and recent Mauna Ulu flows on Hawai’i. These channels formed on Hawai’i as a result of differential flow rates of lava due to viscosity differences. They were characterized by tall a’a Figure 1. This low-resolution THEMIS image from the rift levees, central a’a and pahoehoe channels, and some- apron of Ascraeus Mons immediately south of the chasma- times marginal pahoehoe flows. ta shows multiple associated anastamosing channels, some of which are more defined than others. 62 25th Annual Keck Symposium: 2012 Amherst College, Amherst, MA

Figure 2. This channel to the southwest of Pavonis Mons displays smooth, outwardly-sloping embankments that indicate overflow from the central channel that overlies the surrounding terrain.

We observed a number of lava tubes and collapses, including a collapse tube in the 1801 Hualalai flow and the Thurston lava tube. The Hualalai tube collapsed in a series of pits and skylights (opening at the surface), though in many places the subsurface tube was preserved. In such places, the surface often bulged, and a positive relief feature mimicking the course of the tube was identifiable. The skylights often had walls that could not be seen from the surface because remnants of the flow were still hanging over the cusp. However, some of them had sloping walls all the way to the floor composed of large and small fragments from the flows above. This was probably due, in part, to the fact that this flow was much older and had more time to erode. These tubes varied in depth, with some (e.g. the Hualalai tube) occurring just below the sur- Figure 3. Sinuous channels on the rift aprons of volcanoes face and others (e.g. the historic 750-1500 BP Mauna in the Tharsis Province: (a) a 270 km channel extending Loa tube) flowing much deeper. east from Ascraeus Mons; (b) a 120 km channel extending southwest from Pavonis Mons. DISCUSSION AND CONCLUSIONS walls, and no levees (Bleacher et al., 2010; Murray et Channel features on Ascraeus Mons and Pavonis al., 2010). Though braids appear to be fewer on the Mons are very similar. The morphologies in ques- rift apron of Pavonis Mons than on Ascraeus Mons, tion, sinuous channels, appear in both locations (Fig. streamlined islands (initially interpreted as evidence 3). Their scales are similar and they display the same for fluvial processes) can be found in relative abun- characteristics: relatively high sinuosity, hanging dance in the Pavonis Mons channels. 63 25th Annual Keck Symposium: 2012 Amherst College, Amherst, MA More importantly, however, streamlined islands were emanating from the main channel and superposing also found in known volcanic channels—that is, lev- existing features. eed channels whose origins are generally accepted as volcanic (Hiesinger et al., 2007; Garry et al., 2007b; Because the morphologies of the channels and sur- Zimbelman, 1985)—around Pavonis Mons (Fig. 4). rounding features on Ascraeus Mons and Pavonis These are small (>200 m in length) and clearly in- Mons are so similar, it is logical to conclude that they dicated where the channel banks migrate outward, were formed in analogous ways. However, under accommodating the disruption in flow. Unlike the As- comparable resolution, some of the Pavonis channels craeus Mons channels, which tended to be surrounded display diagnostic features that those on Ascraeus by a smooth surface embayed by younger materials Mons do not. This provides us with an effective (Bleacher et al., 2010), the Pavonis Mons channels point of comparison in determining the origin of the have distinct downslope-oriented overflow margins channels. For example, we find streamlined islands in the sinuous channels on Ascraeus Mons (Bleacher et al., 2010; Mouginis-Mark and Christensen, 2005). On Pavonis Mons, they occur in both the ambiguous sinuous channels and known volcanic channels. Ad- ditionally, unlike on Ascraeus, the channels descend- ing from Pavonis show distinct overflow deposits that are sufficiently thick and textured as to represent lava rather than mud or fluvial overbank (Hiesinger et al., 2007; Greeley and Spudis, 1981).

The field trip to Hawai’i shed new insight on the processes producing the channels around Ascraeus Mons on Mars. Numerous features observed on old and new lava flows on the Big Island resembled those on Ascraeus Mons to a surprising degree of detail. The dimensions between the two sets of features are obviously not comparable. Ascraeus Mons is 18 km above Mars datum, while Mauna Kea, the largest volcano on the Big Island, reaches only 10 km above an equivalent elevation (sea floor), or approximately 4 km above sea level and has a slope of about 20° to Ascraeus’s 7° (Williams, 2010). However, their proportions are measurably relatable. Their volumes, heights, and diameters are analogous and the differences can be readily explained by the lower gravity and reduced atmospheric circulation of Mars (Leovy, 2001).

The recently formed leveed channels in the 1907 Mauna Loa flows on Hawai’i strongly resemble leveed channels on Ascraeus Mons (Fig. 5). These channels formed on Hawai’i as a result of differential flow rates of lava due to viscosity differences. The Figure 4. Streamlined islands in a channel on Pavonis Mons. The levees are clearly distinguishable and the channels on Ascraeus have been interpreted by many islands are readily identifiable where the channel banks researchers as having formed this way (Bleacher et have migrated to accommodate them. al., 2010; Wilson and Head, 1994; Zimbelman, 1985; 64 25th Annual Keck Symposium: 2012 Amherst College, Amherst, MA Finally, it is helpful to consider what we see on a larger scale on Hawai’i. A number of lava tubes can be found across the island. Some occur far below the surface (like the Thurston Lava Tube), while others occur just beneath the topmost layer of basalt. The lava tube visible in Figure 2 is partially collapsed, so we can see it from the air. In morphology, it looks strikingly similar to some of the winding channels we observe on the surface of Mars, and if we were to look at some of the thinner channels at a higher resolution, we may very well be able to see breaks and collapse features. Additionally, Hawai’ian lava tubes tend to be wider at their origin and thinner at their terminations (Kauahikua et al., 1998). The channels we see on Ascraeus and Pavonis Montes also tend to have this characteristic, unlike fluvial systems, which typically become wider farther downstream (Jiongxin, 1996; van den Berg, 1995).

Though evidence is not conclusive (e.g. we do not seem to find as many braided channels on Pavonis Mons as on Ascraeus), the similarities with terrestrial volcanic features strongly supports a volcanic origin for the Marian channels. However, in order to more effectively evaluate this conclusion, broader coverage Figure 5. Top: the interior of a leveed channel in the Mau- of higher resolution imagery will be necessary. na Loa 1907 lava flow, Hawai’i. Bottom: a leveed channel and cross-section (data in meters) from THEMIS visible REFERENCES imagery and MOLA data on the southwest rift apron of Ascraeus Mons. The similar morphology of these features Bleacher, J.E., de Wet, A.P., Garry, W.B., Zimbel- is suggestive of similar processes of formation. man, J.R., and Trumble, M.E., 2010, Volcanic or fluvial: comparison of an Ascraeus Mons, Mars, braided and sinuous channel with features of the Greely and Spudis, 1981), though their origin is still 1859 Mauna Loa flow and Mare Imbrium flows: debated. [Insert Figure 5] Lunar and Planetary Science Conference, 41st, The Woodlands, Texas, Abstracts, no. 1612. Streamlined islands also appeared in the flows on Hawai’i. Though we did not find them occurring Bleacher, J.E., Greeley, R., Williams, D.A., Cave, inside channels (the a’a generally made it very dif- S.R., and Neukum, G., 2007, Trends in effusive ficult to distinguish such specific features on a small style at the Tharsis Montes, Mars, and implica- scale), they are nevertheless evidence of the ability tions for the development of the Tharsis prov- of lava to form streamlined islands. The Hawai’ian ince: Journal of Geophysical Research, v. 112, streamlined islands are accretionary—they formed as E09005, 15 p., doi:10.1029/2006JE002873. lava splashed up and solidified against a solid ob- stacle. We can only see this in side view, however. It Christensen, P.R., Jakosky, B.M., Kieffer, H.H., is impossible to tell from above whether the Martian Malin, M.C., McSween Jr., H.Y., Nealson, K., streamlined islands are accretionary or, as Levering- Mehall, G.L., Silverman, S.H., Ferry, S., Ca- ton (2004) supposed, incised. plinger, M., and Ravine, M., 2004, the Thermal 65 25th Annual Keck Symposium: 2012 Amherst College, Amherst, MA Emission Imaging System (THEMIS) for Mars Kauahikaua, J., Cashman, K.V., Mattox, T.M., He- 2001 Odyssey Mission: Space Science Reviews, liker, C.C., Hon, K.A., Mangan, M.T.,and Thorn- v. 110, p. 85-130. ber, C.R., 1998, Observations of basaltic lava streams in tubes from Kilauea Volcano, Island Garry, W.B., Zimbelman, J.R., and Gregg, T.K.P., of Hawai’i: Journal of Geophysical Research, v. 2007b. Morphology and emplacement of a long 103 (B11), p. 27,303-27,323. channeled lava flow near Ascreus Mons volcano, Mars: Journal of Geophysical Research v. 112, Leovy, C., 2001, Weather and climate on Mars: Na- E08007, 21 p., doi:10.1029/2006JE002803. ture, v. 412, p. 245-249.

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