A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment
We revisit the early evolution of the Moon's bombardment. Our work combines modeling (based on plausible projectile sources and their dynamical decay rates) with constraints from the lunar crater record, radiometric ages of the youngest lunar basins, and the abundance of highly siderophile elem...
Main Authors: | , , , |
---|---|
Format: | Text |
Language: | unknown |
Published: |
arXiv
2012
|
Subjects: | |
Online Access: | https://dx.doi.org/10.48550/arxiv.1208.4624 https://arxiv.org/abs/1208.4624 |
id |
ftdatacite:10.48550/arxiv.1208.4624 |
---|---|
record_format |
openpolar |
spelling |
ftdatacite:10.48550/arxiv.1208.4624 2023-05-15T18:23:16+02:00 A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment Morbidelli, Alessandro Marchi, Simone Bottke, William F. Kring, David A. 2012 https://dx.doi.org/10.48550/arxiv.1208.4624 https://arxiv.org/abs/1208.4624 unknown arXiv https://dx.doi.org/10.1016/j.epsl.2012.07.037 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences article-journal Article ScholarlyArticle Text 2012 ftdatacite https://doi.org/10.48550/arxiv.1208.4624 https://doi.org/10.1016/j.epsl.2012.07.037 2022-04-01T13:36:27Z We revisit the early evolution of the Moon's bombardment. Our work combines modeling (based on plausible projectile sources and their dynamical decay rates) with constraints from the lunar crater record, radiometric ages of the youngest lunar basins, and the abundance of highly siderophile elements in the lunar crust and mantle. We deduce that the evolution of the impact flux did not decline exponentially over the first billion years of lunar history, but also there was no prominent and "narrow" impact spike some 3.9 Gy ago, unlike that typically envisioned in the lunar cataclysm scenario. Instead, we show the timeline of the lunar bombardment has a sawtooth-like profile, with an uptick in the impact flux near 4.1 Gy ago. The impact flux at the beginning of this weaker cataclysm was 5-10 times higher than the immediately preceding period. The Nectaris basin should have been one of the first basins formed at the sawtooth. We predict the bombardment rate since about 4.1Gy ago declined slowly and adhered relatively close to classic crater chronology models (Neukum and Ivanov (1994)). Overall we expect that the sawtooth event accounted for about 1/4 of the total bombardment suffered by the Moon since its formation. Consequently, considering that about 12-14 basins formed during the sawtooth event, we expect that the net number of basins formed on the Moon was about 45-50. From our expected bombardment timeline, we derived a new and improved lunar chronology suitable for use on Pre-Nectarian surface units. According to this chronology, a significant portion of the oldest lunar cratered terrains has an age of 4.38-4.42 Gyr. Moreover, the largest lunar basin, South Pole Aitken, is older than 4.3Gy, and therefore was not produced during the lunar cataclysm. : In press in EPSL Text South pole DataCite Metadata Store (German National Library of Science and Technology) Aitken ENVELOPE(-44.516,-44.516,-60.733,-60.733) South Pole |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences |
spellingShingle |
Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences Morbidelli, Alessandro Marchi, Simone Bottke, William F. Kring, David A. A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment |
topic_facet |
Earth and Planetary Astrophysics astro-ph.EP FOS Physical sciences |
description |
We revisit the early evolution of the Moon's bombardment. Our work combines modeling (based on plausible projectile sources and their dynamical decay rates) with constraints from the lunar crater record, radiometric ages of the youngest lunar basins, and the abundance of highly siderophile elements in the lunar crust and mantle. We deduce that the evolution of the impact flux did not decline exponentially over the first billion years of lunar history, but also there was no prominent and "narrow" impact spike some 3.9 Gy ago, unlike that typically envisioned in the lunar cataclysm scenario. Instead, we show the timeline of the lunar bombardment has a sawtooth-like profile, with an uptick in the impact flux near 4.1 Gy ago. The impact flux at the beginning of this weaker cataclysm was 5-10 times higher than the immediately preceding period. The Nectaris basin should have been one of the first basins formed at the sawtooth. We predict the bombardment rate since about 4.1Gy ago declined slowly and adhered relatively close to classic crater chronology models (Neukum and Ivanov (1994)). Overall we expect that the sawtooth event accounted for about 1/4 of the total bombardment suffered by the Moon since its formation. Consequently, considering that about 12-14 basins formed during the sawtooth event, we expect that the net number of basins formed on the Moon was about 45-50. From our expected bombardment timeline, we derived a new and improved lunar chronology suitable for use on Pre-Nectarian surface units. According to this chronology, a significant portion of the oldest lunar cratered terrains has an age of 4.38-4.42 Gyr. Moreover, the largest lunar basin, South Pole Aitken, is older than 4.3Gy, and therefore was not produced during the lunar cataclysm. : In press in EPSL |
format |
Text |
author |
Morbidelli, Alessandro Marchi, Simone Bottke, William F. Kring, David A. |
author_facet |
Morbidelli, Alessandro Marchi, Simone Bottke, William F. Kring, David A. |
author_sort |
Morbidelli, Alessandro |
title |
A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment |
title_short |
A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment |
title_full |
A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment |
title_fullStr |
A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment |
title_full_unstemmed |
A Sawtooth-like Timeline for the First Billion Year of Lunar Bombardment |
title_sort |
sawtooth-like timeline for the first billion year of lunar bombardment |
publisher |
arXiv |
publishDate |
2012 |
url |
https://dx.doi.org/10.48550/arxiv.1208.4624 https://arxiv.org/abs/1208.4624 |
long_lat |
ENVELOPE(-44.516,-44.516,-60.733,-60.733) |
geographic |
Aitken South Pole |
geographic_facet |
Aitken South Pole |
genre |
South pole |
genre_facet |
South pole |
op_relation |
https://dx.doi.org/10.1016/j.epsl.2012.07.037 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1208.4624 https://doi.org/10.1016/j.epsl.2012.07.037 |
_version_ |
1766202831825534976 |