Home > Research > Publications & Outputs > Ina pit crater on the Moon

Electronic data

  • 5131_text_plus_figs

    Accepted author manuscript, 821 KB, PDF document

    Available under license: CC BY-NC: Creative Commons Attribution-NonCommercial 4.0 International License

Links

Text available via DOI:

View graph of relations

Ina pit crater on the Moon: extrusion of waning-stage lava lake magmatic foam results in extremely young crater retention ages

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Published
  • Le Qiao
  • James Head
  • Lionel Wilson
  • Long Xiao
  • Mikhail Kreslavsky
  • Josef Dufek
Close
<mark>Journal publication date</mark>05/2017
<mark>Journal</mark>Geology
Issue number5
Volume45
Number of pages4
Pages (from-to)455-458
Publication StatusPublished
Early online date15/03/17
<mark>Original language</mark>English

Abstract

The enigmatic Ina feature on the Moon was recently interpreted to represent extrusive basaltic volcanic activity within the past 100 m.y. of lunar history, an extremely young age for volcanism on the Moon. Ina is a 2 × 3 km D-shaped depression that consists of a host of unusual bleb-like mounds surrounded by a relatively optically fresh hummocky and blocky floor. Documentation of magmatic-volcanic processes from shield volcano summit pit craters in Hawai’i and new insights into shield-building and dike evolution processes on the Moon provide important perspectives on the origin of Ina. We show that the size, location, morphology, topography, and optical maturity of Ina are consistent with an origin as a subsided summit pit crater lava lake on top of a broad ~22-km-diameter, ~3.5-b.y.-old shield volcano. New theoretical treatments of lunar shield-building magmatic dike events predict that waning-stage summit activity was characterized by the production of magmatic foam in the dike and lake; the final stages of dike stress relaxation and closure cause the magmatic foam to extrude to the surface through cracks in the lava lake crust to produce the mounds. The high porosity of the extruded foams (>75%) altered the nature of subsequent impact craters (the aerogel effect), causing them to be significantly smaller in diameter, which could bias the crater-derived model ages. Accounting for this effect allows for significantly older model ages, to ~3.5 b.y., contemporaneous with the underlying shield volcano. Thus extremely young volcanic eruptions are not required to explain the unusual nature of Ina.