title: Structure and evolution of the lunar Procellarum region as revealed by GRAIL gravity data.
abstract: The Procellarum region is a broad area on the nearside of the Moon that is characterized by low elevations, thin crust, and high surface concentrations of the heat-producing elements uranium, thorium, and potassium. The region has been interpreted as an ancient impact basin approximately 3,200 kilometres in diameter, although supporting evidence at the surface would have been largely obscured as a result of the great antiquity and poor preservation of any diagnostic features. Here we use data from the Gravity Recovery and Interior Laboratory (GRAIL) mission to examine the subsurface structure of Procellarum. The Bouguer gravity anomalies and gravity gradients reveal a pattern of narrow linear anomalies that border Procellarum and are interpreted to be the frozen remnants of lava-filled rifts and the underlying feeder dykes that served as the magma plumbing system for much of the nearside mare volcanism. The discontinuous surface structures that were earlier interpreted as remnants of an impact basin rim are shown in GRAIL data to be a part of this continuous set of border structures in a quasi-rectangular pattern with angular intersections, contrary to the expected circular or elliptical shape of an impact basin. The spatial pattern of magmatic-tectonic structures bounding Procellarum is consistent with their formation in response to thermal stresses produced by the differential cooling of the province relative to its surroundings, coupled with magmatic activity driven by the greater-than-average heat flux in the region.
authors.affiliation: Department of Geophysics and Center for Space Resources, Colorado School of Mines, Golden, Colorado 80401, USA.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Andrews-Hanna
authors.affiliation: Department of Earth and Planetary Sciences, University of California, Santa Cruz, California 95064, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Besserer
authors.affiliation: Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Head
authors.affiliation: Planetary Science Directorate, Southwest Research Institute, Boulder, Colorado 80302, USA.
authors.forename: Carly J A
authors.initials: CJ
authors.lastname: Howett
authors.affiliation: Lunar and Planetary Institute, Houston, Texas 77058, USA.
authors.forename: Walter S
authors.initials: WS
authors.lastname: Kiefer
authors.affiliation: Hawaii Institute of Geophysics and Planetology, University of Hawaii, Honolulu, Hawaii 96822, USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lucey
authors.affiliation: Lunar and Planetary Institute, Houston, Texas 77058, USA.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: McGovern
authors.affiliation: Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: H Jay
authors.initials: HJ
authors.lastname: Melosh
authors.affiliation: Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Neumann
authors.affiliation: Planetary Science Directorate, Southwest Research Institute, Boulder, Colorado 80302, USA.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Phillips
authors.affiliation: Lunar and Planetary Institute, Houston, Texas 77058, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Schenk
authors.affiliation: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Smith
authors.affiliation: 1] Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington DC 20015, USA [2] Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Solomon
authors.affiliation: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Zuber