Letter | Published:

Recent tectonic activity on Mercury revealed by small thrust fault scarps

Nature Geoscience volume 9, pages 743747 (2016) | Download Citation

Abstract

Large tectonic landforms on the surface of Mercury, consistent with significant contraction of the planet, were revealed by the flybys of Mariner 10 in the mid-1970s1. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission confirmed that the planet’s past 4 billion years of tectonic history have been dominated by contraction expressed by lobate fault scarps that are hundreds of kilometres long2,3,4,5. Here we report the discovery of small thrust fault scarps in images from the low-altitude campaign at the end of the MESSENGER mission that are orders of magnitude smaller than the large-scale lobate scarps. These small scarps have tens of metres of relief, are only kilometres in length and are comparable in scale to small young scarps on the Moon6,7,8. Their small-scale, pristine appearance, crosscutting of impact craters and association with small graben all indicate an age of less than 50 Myr. We propose that these scarps are the smallest members of a continuum in scale of thrust fault scarps on Mercury. The young age of the small scarps, along with evidence for recent activity on large-scale scarps, suggests that Mercury is tectonically active today and implies a prolonged slow cooling of the planet’s interior.

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Acknowledgements

We thank P. D. Spudis and A. Nahm for helpful comments and suggestions that greatly improved the manuscript. We also thank C. Johnson for valuable discussions. We are grateful to S. C. Solomon, the MDIS team, and the MESSENGER engineers, and technical support personnel at Johns Hopkins University Applied Physics Laboratory. This work is also supported by NASA grant NNX07AR60G.

Author information

Affiliations

  1. Center for Earth and Planetary Studies, Smithsonian Institution, Washington DC 20560, USA

    • Thomas R. Watters
    • , Katie Daud
    • , Maria E. Banks
    •  & Michelle M. Selvans
  2. Planetary Science Institute, Tucson, Arizona 85719, USA

    • Maria E. Banks
  3. Planetary Science Directorate, Southwest Research Institute, Boulder, Colorado 80302, USA

    • Clark R. Chapman
  4. The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723, USA

    • Carolyn M. Ernst

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Contributions

T.R.W. drafted the manuscript. K.D., M.E.B. and M.M.S. assisted with image processing and the identification of tectonic features. C.R.C., M.E.B. and C.M.E. contributed to the analysis of the age of the tectonic landforms. C.M.E. assisted with the processing and analysis of Mercury Laser Altimeter data. All of the authors contributed to interpretation and analysis of the data.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Thomas R. Watters.

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DOI

https://doi.org/10.1038/ngeo2814