Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes.
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| Title: | Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes. |
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| Authors: | Evans, Alexander J.1,2 alex@lpl.arizona.edu, Andrews‐Hanna, Jeffrey C.1,2, Head, III, James W.3, Soderblom, Jason M.4, Solomon, Sean C.5,6, Zuber, Maria T.4 |
| Source: | Journal of Geophysical Research. Planets. Jul2018, Vol. 123 Issue 7, p1596-1617. 22p. |
| Abstract: | Abstract: Flooding of the lunar surface by ancient mare basalts has rendered uncertain the ages of lunar geochemical terranes and several impact basins. Here we combine craters having recognizable surface expressions with craters identified only by their gravitational signatures in Gravity Recovery and Interior Laboratory data to reassess the chronological sequence of lunar impact basins and the ages of major lunar geochemical terranes. Our results indicate that although volcanically flooded regions are deficient in craters with diameters greater than 20 km by more than 50% relative to unflooded regions, craters with diameters greater than 90 km can be readily recognized either by topography or by gravity anomaly. On the basis of the areal density of craters with diameters greater than 90 km we conclude that (1) the Serenitatis basin could be as young as the Imbrium basin; (2) the areal density of craters within the Procellarum KREEP Terrane is significantly lower than that for the South Pole‐Aitken basin and the Feldspathic Highlands Terrane; (3) if the youngest age of final crystallization of the lunar magma ocean is adopted as a lower bound on the age of the Procellarum KREEP Terrane, a minimum age of approximately 4.3 Ga is inferred for ~40% of lunar impact basins, including South Pole‐Aitken; and (4) the flux of impactors capable of forming craters with diameters of at least 90 km decreased substantially through the Nectarian and Imbrian periods. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Geophysical Research. Planets is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: 8gh DbLabel: GreenFILE An: 131189432 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Evans%2C+Alexander+J%2E%22">Evans, Alexander J.</searchLink><relatesTo>1,2</relatesTo><i> alex@lpl.arizona.edu</i><br /><searchLink fieldCode="AR" term="%22Andrews‐Hanna%2C+Jeffrey+C%2E%22">Andrews‐Hanna, Jeffrey C.</searchLink><relatesTo>1,2</relatesTo><br /><searchLink fieldCode="AR" term="%22Head%2C+III%2C+James+W%2E%22">Head, III, James W.</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Soderblom%2C+Jason+M%2E%22">Soderblom, Jason M.</searchLink><relatesTo>4</relatesTo><br /><searchLink fieldCode="AR" term="%22Solomon%2C+Sean+C%2E%22">Solomon, Sean C.</searchLink><relatesTo>5,6</relatesTo><br /><searchLink fieldCode="AR" term="%22Zuber%2C+Maria+T%2E%22">Zuber, Maria T.</searchLink><relatesTo>4</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Geophysical+Research%2E+Planets%22">Journal of Geophysical Research. Planets</searchLink>. Jul2018, Vol. 123 Issue 7, p1596-1617. 22p. – Name: Abstract Label: Abstract Group: Ab Data: Abstract: Flooding of the lunar surface by ancient mare basalts has rendered uncertain the ages of lunar geochemical terranes and several impact basins. Here we combine craters having recognizable surface expressions with craters identified only by their gravitational signatures in Gravity Recovery and Interior Laboratory data to reassess the chronological sequence of lunar impact basins and the ages of major lunar geochemical terranes. Our results indicate that although volcanically flooded regions are deficient in craters with diameters greater than 20 km by more than 50% relative to unflooded regions, craters with diameters greater than 90 km can be readily recognized either by topography or by gravity anomaly. On the basis of the areal density of craters with diameters greater than 90 km we conclude that (1) the Serenitatis basin could be as young as the Imbrium basin; (2) the areal density of craters within the Procellarum KREEP Terrane is significantly lower than that for the South Pole‐Aitken basin and the Feldspathic Highlands Terrane; (3) if the youngest age of final crystallization of the lunar magma ocean is adopted as a lower bound on the age of the Procellarum KREEP Terrane, a minimum age of approximately 4.3 Ga is inferred for ~40% of lunar impact basins, including South Pole‐Aitken; and (4) the flux of impactors capable of forming craters with diameters of at least 90 km decreased substantially through the Nectarian and Imbrian periods. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Geophysical Research. Planets is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1029/2017JE005421 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 22 StartPage: 1596 Titles: – TitleFull: Reexamination of Early Lunar Chronology With GRAIL Data: Terranes, Basins, and Impact Fluxes. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Evans, Alexander J. – PersonEntity: Name: NameFull: Andrews‐Hanna, Jeffrey C. – PersonEntity: Name: NameFull: Head, III, James W. – PersonEntity: Name: NameFull: Soderblom, Jason M. – PersonEntity: Name: NameFull: Solomon, Sean C. – PersonEntity: Name: NameFull: Zuber, Maria T. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 07 Text: Jul2018 Type: published Y: 2018 Identifiers: – Type: issn-print Value: 21699097 Numbering: – Type: volume Value: 123 – Type: issue Value: 7 Titles: – TitleFull: Journal of Geophysical Research. Planets Type: main |
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