Lobate impact melt flows within the extended ejecta blanket of Pierazzo crater

Veronica J. Bray, Corwin Atwood-Stone, Catherine D. Neish, Natalia A. Artemieva, Alfred S. McEwen, Jim N. McElwaine

Research output: Research - peer-reviewArticle

Abstract

Impact melt flows are observed within the continuous and discontinuous ejecta blanket of the 9km lunar crater Pierazzo, from the crater rim to more than 40km away from the center of the crater. Our mapping, fractal analysis, and thermal modeling suggest that melt can be emplaced ballistically and, upon landing, can become separated from solid ejecta to form the observed flow features. Our analysis is based on the identification of established melt morphology for these in-ejecta flows and supported by fractal analysis and thermal modeling. We computed the fractal dimension for the flow boundaries and found values of D=1.05-1.17. These are consistent with terrestrial basaltic lava flows (D=1.06-1.2) and established lunar impact melt flows (D=1.06-1.18), but inconsistent with lunar dry granular flows (D=1.31-1.34). Melt flows within discontinuous ejecta deposits are noted within just 1.5% of the mapping area, suggesting that the surface expression of impact melt in the extended ejecta around craters of this size is rare, most likely due to the efficient mixing of melts with solid ejecta and local target rocks. However, if the ejected fragments (both, molten and solid) are large enough, segregation of melt and its consequent flow is possible. As most of the flows mapped in this work occur on crater-facing slopes, the development of defined melt flows within ejecta deposits might be facilitated by high crater-facing topography restricting the flow of ejecta soon after it makes ground contact, limiting the quenching of molten ejecta through turbulent mixing with solid debris. Our study confirms the idea that impact melt can travel far beyond the continuous ejecta blanket, adding to the lunar regolith over an extensive area.

LanguageEnglish (US)
JournalIcarus
DOIs
StateAccepted/In press - 2017

Fingerprint

impact melts
blankets
ejecta
craters
crater
melt
fractals
fractal analysis
modeling
deposits
turbulent mixing
regolith
lava flow
topography
rock
travel
analysis
lunar craters
landing
lava

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Bray, V. J., Atwood-Stone, C., Neish, C. D., Artemieva, N. A., McEwen, A. S., & McElwaine, J. N. (2017). Lobate impact melt flows within the extended ejecta blanket of Pierazzo crater. Icarus. DOI: 10.1016/j.icarus.2017.10.002

Lobate impact melt flows within the extended ejecta blanket of Pierazzo crater. / Bray, Veronica J.; Atwood-Stone, Corwin; Neish, Catherine D.; Artemieva, Natalia A.; McEwen, Alfred S.; McElwaine, Jim N.

In: Icarus, 2017.

Research output: Research - peer-reviewArticle

Bray, VJ, Atwood-Stone, C, Neish, CD, Artemieva, NA, McEwen, AS & McElwaine, JN 2017, 'Lobate impact melt flows within the extended ejecta blanket of Pierazzo crater' Icarus. DOI: 10.1016/j.icarus.2017.10.002
Bray VJ, Atwood-Stone C, Neish CD, Artemieva NA, McEwen AS, McElwaine JN. Lobate impact melt flows within the extended ejecta blanket of Pierazzo crater. Icarus. 2017. Available from, DOI: 10.1016/j.icarus.2017.10.002
Bray, Veronica J. ; Atwood-Stone, Corwin ; Neish, Catherine D. ; Artemieva, Natalia A. ; McEwen, Alfred S. ; McElwaine, Jim N./ Lobate impact melt flows within the extended ejecta blanket of Pierazzo crater. In: Icarus. 2017
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