Origin and implications of non-radial Imbrium Sculpture on the Moon

Journal Article · Wed Jul 20 00:00:00 EDT 2016 · Nature (London)

DOI:https://doi.org/10.1038/nature18278· OSTI ID:1321817

Schultz, Peter H. ^[1]; Crawford, David A. ^[2]

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1. Brown Univ., Providence, RI (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Rimmed grooves, lineations and elongate craters around Mare Imbrium shape much of the nearside Moon. This pattern was coined the Imbrium Sculpture¹, and it was originally argued that it must have been formed by a giant oblique (~30°) impact, a conclusion echoed by later studies². Some investigators, however, noticed that many elements of the Imbrium Sculpture are not radial to Imbrium, thereby implicating an endogenic or structural origin^{3, 4}. Here we use these non-radial trends to conclude that the Imbrium impactor was a proto-planet (half the diameter of Vesta), once part of a population of large proto-planets in the asteroid belt. Such independent constraints on the sizes of the Imbrium and other basin-forming impactors markedly increase estimates for the mass in the asteroid belt before depletion caused by the orbital migration of Jupiter and Saturn⁵. Furthermore, laboratory impact experiments, shock physics codes and the groove widths indicate that multiple fragments (up to 2% of the initial diameter) from each oblique basin-forming impactor, such as the one that formed Imbrium, should have survived planetary collisions and contributed to the heavy impact bombardment between 4.3 and 3.8 billion years ago.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1321817
• Report Number(s): SAND-2016-5142J; 640983
• Journal Information: Nature (London), Vol. 535, Issue 7612; ISSN 0028-0836
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS