Skip to main content
SpringerLink
Log in

Fine-Ejecta Halo

  • Living reference work entry
  • First Online:
Encyclopedia of Planetary Landforms

  • 379 Accesses

Definition

A halo of material characterized by anomalous radar or thermal properties around impact craters interpreted as fine-grained ejecta.

Category

A type of Crater-associated radar-dark diffuse feature

Synonyms

Low nighttime temperature halo (Mars); Nonparabolic (radar-) dark halo; Radar-dark halo; Radar-dark mantle (this term is used also for pyroclastic deposits on the Moon)

Description

  1. (1)

    Anomalous radar properties: A clear or faint radar-dark halo that surrounds an impact crater and extends beyond its radar-bright continuous ejecta (Venus, Moon).

  2. (2)

    Anomalous thermal properties: Crater halos characterized by low nighttime surface temperatures and relatively low values of thermal inertia (Mars). Venusian and Martian fine-ejecta halos are larger than on the Moon.

Interpretation

Low radar backscatter indicates fine-grained (smooth) material.

Venusian radar-dark halos represent a veneer of fine-particulate, rock-poor material covering the local bedrock (Basilevsky et al. 2012).

O...

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution

Institutional subscriptions

References

  • Basilevsky AT, Head JW (2002) Venus: analysis of the degree of impact crater deposit degradation and assessment of its use for dating geological units and features. J Geophys Res 107(E8):5061. doi:10.1029/2001JE001584

    Article  Google Scholar 

  • Basilevsky AT, Shalygin EV, Titov DV, Markiewicz WJ, Scholten F et al (2012) Geologic interpretation of the near-infrared images of the surface taken by the Venus Monitoring Camera, Venus express. Icarus 217:434–450

    Article  Google Scholar 

  • Campbell BA, Campbell DB, Carter LM, Morgan GA, Hawke BR, Nolan M (2013) Earth-based radar data for the Moon at 12.6-cm and 70-cm wavelengths: mapping update and science results. 44th Lunar Planet Sci Conf, abstract #2291, Houston

    Google Scholar 

  • Ghent RR, Leverington DW, Campbell BA, Hawke BR, Campbell DB (2005) Earth-based observations of radar-dark crater haloes on the Moon: implications for regolith properties. J Geophys Res 110. doi:dx.doi.org/10.1029/2004JE002366

    Google Scholar 

  • Ghent RR, Gupta V, Campbell BA, Ferguson SA, Brown JCW et al (2010) Generation and emplacement of fine-grained ejecta in planetary impacts. Icarus 209:818–835

    Article  Google Scholar 

  • Schultz PH, Mendell W (1978) Orbital infrared observations of lunar craters and possible implications for impact ejecta emplacement. Proc Lunar Planet Sci Conf 9th:2857–2883, Houston

    Google Scholar 

  • Short NM, Forman ML (1972) Thickness of impact crater ejecta on the lunar surface. Modern Geol 3:69–91

    Google Scholar 

  • Thompson TW, Pollack JB, Campbell MH, O’Leary BT (1970) Radar maps of the Moon at 70-cm wavelength and their interpretation. Radio Sci 5(2):253–262

    Article  Google Scholar 

  • Thompson TW, Zisk SH, Shorthill RW, Schultz PH, Cutts JA (1981) Lunar craters with radar bright ejecta. Icarus 46:201–225

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Earth Sciences, University of Toronto, Toronto, ON, Canada

    Rebecca Ghent

Authors
  1. Rebecca Ghent
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Rebecca Ghent .

Rights and permissions

Reprints and permissions

Copyright information

© 2014 Springer Science+Business Media New York

About this entry

Cite this entry

Ghent, R. (2014). Fine-Ejecta Halo. In: Encyclopedia of Planetary Landforms. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-9213-9_291-1

Download citation

  • DOI: https://doi.org/10.1007/978-1-4614-9213-9_291-1

  • Received:

  • Accepted:

  • Published:

  • Publisher Name: Springer, New York, NY

  • Online ISBN: 978-1-4614-9213-9

  • eBook Packages: Springer Reference Earth and Environm. ScienceReference Module Physical and Materials ScienceReference Module Earth and Environmental Sciences

Publish with us

Policies and ethics

Search

Navigation