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Origin of nearside structural and geochemical anomalies on the Moon

Peter H. Schultz and David A. Crawford
Origin of nearside structural and geochemical anomalies on the Moon (in Recent advances and current research issues in lunar stratigraphy, William A. Ambrose (editor) and David A. Williams (editor))
Special Paper - Geological Society of America (March 2011) 477: 141-159


Mare basalts cover much of the Earth-facing side of the Moon. The underlying cause for this distribution has been attributed to an ancient nearside megabasin, asymmetric accretion, and differential tidal effects. While each hypothesis is plausible, the hypothesis for a megabasin also accounts for a subconcentric and radial system of graben and ridges that centers on a region southwest of Imbrium Basin. Moreover, such a nearside megabasin could account for the distribution of nearside geochemical anomalies related to localized igneous intrusions. The farside South Pole-Aitken Basin, however, is a well-established impact megabasin exceeding 2200 km in diameter. Here, we propose an oblique collision scenario for this basin on the farside that would have created the initial conditions for localized deep-seated and long-lasting weaknesses on the nearside. Laboratory and computational experiments demonstrate that a large oblique collision generates asymmetric shock waves that converge in a region offset from the basin-center antipode. The resulting damage would have provided pathways for deep magma to reach shallow reservoirs.

ISSN: 0072-1077
EISSN: 2331-219X
Serial Title: Special Paper - Geological Society of America
Serial Volume: 477
Title: Origin of nearside structural and geochemical anomalies on the Moon
Title: Recent advances and current research issues in lunar stratigraphy
Author(s): Schultz, Peter H.Crawford, David A.
Author(s): Ambrose, William A.editor
Author(s): Williams, David A.editor
Affiliation: Brown University, Department of Geological Sciences, Providence, RI, United States
Affiliation: University of Texas at Austin, Bureau of Economic Geology, Austin, TX, United States
Pages: 141-159
Published: 201103
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 62
Accession Number: 2011-050334
Categories: Extraterrestrial geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps
Secondary Affiliation: Arizona State University, USA, United StatesSandia National Laboratories, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201128
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