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Onset and migration of spiral troughs on Mars revealed by orbital radar

Abstract

The landscape of the north polar layered deposits of Mars (NPLD) is dominated by a pinwheel array of enigmatic spiral troughs1. The troughs have intrigued planetary scientists since the Mariner 9 spacecraft returned the first close-up image in 1972, but conclusive evidence of their origin has remained elusive. Debate continues regarding all aspects of the troughs, including the possibility that they have migrated2,3,4,5, their age in relation to the current NPLD surface6, and whether they are fundamentally erosional6,7 or constructional2,4 features. The troughs are probably related to climatic processes2,8, yet the nature of this relationship has remained a mystery. Previous data characterizing only the exposed NLPD surface were insufficient to test these hypotheses. Here we show that the central spiral troughs initiated after deposition of three-quarters of the NPLD, quickly reached a stable morphology and migrated approximately 65 kilometres poleward and 600 metres in altitude over the past two million years or so. Our radar stratigraphy rules out hypotheses of erosional incision post-dating deposition6,7,9,10, and instead largely validates an early hypothesis for constructional trough migration2,3,4,5 with wind transport and atmospheric deposition as dominant processes. These results provide hard constraints for palaeo-climate models and a new context for evaluating imagery, spectral data, and now radar sounding data, the better to understand the link between orbital parameters and climate, the role of climate in shaping the polar ice of Mars, and eventually, the age of the polar deposits themselves8,11,12,13.

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Figure 1: NPLD with locations of data.
Figure 2: SHARAD data over troughs.
Figure 3: Stratigraphy and layer thickness changes resulting from different proposed mechanisms of trough formation/migration.
Figure 4: Image of trough and effect of katabatic winds.

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References

  1. Cutts, J., Blasius, K. & Roberts, W. Evolution of Martian polar landscapes—interplay of long-term variations in perennial ice cover and dust storm intensity. J. Geophys. Res. 84, 2975–2994 (1979)

    Article  ADS  Google Scholar 

  2. Squyres, S. W. The evolution of dust deposits in the Martian north polar region. Icarus 40, 244–261 (1979)

    Article  ADS  CAS  Google Scholar 

  3. Howard, A. D. Origin of the stepped topography of the Martian poles. Icarus 34, 581–599 (1978)

    Article  ADS  Google Scholar 

  4. Howard, A. D., Cutts, J. A. & Blasius, K. R. Stratigraphic relationships within Martian polar cap deposits. Icarus 50, 161–215 (1982)

    Article  ADS  Google Scholar 

  5. Howard, A. D. The role of eolian processes in forming surface features of the Martian polar layered deposits. Icarus 144, 267–288 (2000)

    Article  ADS  Google Scholar 

  6. Tanaka, K. L. et al. North polar region of Mars: advances in stratigraphy, structure, and erosional modification. Icarus 196, 318–358 (2008)

    Article  ADS  Google Scholar 

  7. Kolb, E. J. & Tanaka, K. L. Geologic history of the polar regions of Mars based on Mars Global Surveyor data. II. Amazonian period. Icarus 154, 22–39 (2001)

    Article  ADS  Google Scholar 

  8. Milkovich, S. M. & Head, J. W. North polar cap of Mars: polar layered deposit characterization and identification of a fundamental climate signal. J. Geophys. Res. 110 10.1029/2004JE002349 (2005)

  9. Pelletier, J. D. How do spiral troughs form on Mars? Geology 32, 365–367 (2004)

    Article  ADS  Google Scholar 

  10. Winebrenner, D. P. et al. Evidence for ice flow prior to trough formation in the Martian north polar layered deposits. Icarus 195, 90–105 (2008)

    Article  ADS  Google Scholar 

  11. Head, J. W., Mustard, J. F., Kreslavsky, M. A., Milliken, R. E. & Marchant, D. R. Recent ice ages on Mars. Nature 426, 797–802 (2003)

    Article  ADS  CAS  Google Scholar 

  12. Fishbaugh, K. E. & Head, J. W. Origin and characteristics of the Mars north polar basal unit and implications for polar geologic history. Icarus 174, 444–474 (2005)

    Article  ADS  CAS  Google Scholar 

  13. Cutts, J. A. & Lewis, B. H. Models of climate cycles recorded in Martian polar layered deposits. Icarus 50, 216–244 (1982)

    Article  ADS  Google Scholar 

  14. Cutts, J. A. Wind erosion in the Martian polar region. J. Geophys. Res. 78 (20) 4211–4221 (1973)

    Article  ADS  Google Scholar 

  15. Soderblom, L. A., Malin, M. C., Murray, B. & Cutts, J. Mariner 9 observations of the surface of Mars in the north polar region. J. Geophys. Res. 78, 4197–4210 (1973)

    Article  ADS  Google Scholar 

  16. Zeng, Z. et al. Evidence of fractures in NPLD and their significance to the formation of Martian polar spiral troughs. 39th Lunar Planet. Sci. Conf. abstr. 2179 (Lunar and Planetary Institute, 2008) 〈http://www.lpi.usra.edu/meetings/lpsc2008/pdf/2179.pdf〉.

  17. Ng, F. S. L. & Zuber, M. T. Patterning instability on the Mars polar ice caps. J. Geophys. Res. Planets 111, E02005 (2006)

    Article  ADS  Google Scholar 

  18. Fisher, D. A. Internal layers in an “accublation” ice cap: a test for flow. Icarus 144, 289–294 (2000)

    Article  ADS  CAS  Google Scholar 

  19. Weijermars, R. The polar spirals of Mars may be due to glacier surges deflected by Coriolis forces. Earth Planet. Sci. Lett. 76, 227–240 (1986)

    Article  ADS  Google Scholar 

  20. Fisher, D. A. If Martian ice caps flow: ablation mechanisms and appearance. Icarus 105, 501–511 (1993)

    Article  ADS  Google Scholar 

  21. Picardi, G. et al. Radar soundings of the subsurface of Mars. Science 310, 1925–1928 (2005)

    Article  ADS  CAS  Google Scholar 

  22. Seu, R. et al. SHARAD sounding radar on the Mars Reconnaissance Orbiter. J. Geophys. Res. Planets 112, E05S05 (2007)

    Article  Google Scholar 

  23. Phillips, R. J. et al. Mars north polar deposits: stratigraphy, age, and geodynamical response. Science 320, 1182–1185 (2008)

    Article  ADS  CAS  Google Scholar 

  24. Grima, C. et al. North polar deposits of Mars: extreme purity of the water ice. Geophys. Res. Lett. 36, L03203 (2009)

    Article  ADS  Google Scholar 

  25. Nunes, D. C. & Phillips, R. J. Radar subsurface mapping of the polar layered deposits on Mars. J. Geophys. Res. Planets 111, E06S21 (2006)

    Article  ADS  Google Scholar 

  26. Milkovich, S. M. & Plaut, J. J. Martian south polar layered deposit stratigraphy and implications for accumulation history. J. Geophys. Res. Planets 113, E06007 (2008)

    Article  ADS  Google Scholar 

  27. Holt, J. W. et al. The construction of Chasma Boreale on Mars. Nature 10.1038/nature09050 (this issue)

  28. Fishbaugh, K. E. & Hvidberg, C. S. Martian north polar layered deposits stratigraphy: implications for accumulation rates and flow. J. Geophys. Res. Planets 111, E06012 (2006)

    Article  ADS  Google Scholar 

  29. Smith, D. E. et al. Mars Orbiter Laser Altimeter: experiment summary after the first year of global mapping of Mars. J. Geophys. Res. Planets 106 10.1029/2000JE001364 (2001)

  30. Christensen, P., Gorelick, N., Mehall, G. & Murray, K. THEMIS Public Data Releases. 〈http://themis-data.asu.edu〉 (Planetary Data System node, Arizona State University)

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Acknowledgements

This work was supported by NASA grant NAG5-12693 to J.H. and by the Gayle White Fellowship at the University of Texas Institute for Geophysics. We especially thank D. Young, S. Kempf, C. Brothers and S. Christian for listening to ideas and for help preparing the data and images. We thank A. Howard for insight and comments, and the SHARAD Operations Center for their continuous support in data acquisition. We dedicate this paper to the memory of SHARAD team member Ali Safaenili, who provided the focused radargrams we use. This is UTIG contribution 2187.

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I.B.S. interpreted the data, created figures, and wrote the paper. J.W.H. wrote and edited the paper and figures and assisted in interpretation.

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Correspondence to Isaac B. Smith.

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The authors declare no competing financial interests.

Additional information

Data from the Mars Reconnaissance Orbiter, including SHARAD and HiRISE, are available at NASA’s Planetary Data System (http://pds.jpl.nasa.gov/).

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Supplementary Information

This file contains Supplementary Notes S1-S5, Supplementary Figures S1-S5 with legends and References. (PDF 606 kb)

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Smith, I., Holt, J. Onset and migration of spiral troughs on Mars revealed by orbital radar. Nature 465, 450–453 (2010). https://doi.org/10.1038/nature09049

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