Pre-Nectarian
Geologic period, 4533 to 3920 million years ago
title: "Pre-Nectarian" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["pre-nectarian"] description: "Geologic period, 4533 to 3920 million years ago" topic_path: "general/pre-nectarian" source: "https://en.wikipedia.org/wiki/Pre-Nectarian" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Geologic period, 4533 to 3920 million years ago ::
::data[format=table title="Infobox geologic timespan"]
| Field | Value |
|---|---|
| name | Pre-Nectarian |
| manual_color | rgb(209.0, 77.0, 96.0) |
| top_bar | Lunar |
| time_start | 4533 |
| time_end | 3920 |
| timeline | Lunar periods |
| celestial_body | moon |
| timescales_used | Lunar Geologic Timescale |
| chrono_unit | Period |
| :: |
| name = Pre-Nectarian | manual_color = rgb(209.0, 77.0, 96.0) | top_bar = Lunar | time_start = 4533 | time_end = 3920 | image_map = | caption_map = | image_outcrop = | caption_outcrop = | image_art = | caption_art = | timeline = Lunar periods | subdivisions = | proposed_subdivision1 = | proposed_subdivision1_coined = | proposed_subdivision2 = | proposed_subdivision2_coined = | proposed_subdivision3 = | proposed_subdivision3_coined = | former_subdivisions = | formerly_part_of = | partially_contained_in = | partially_contains = | chrono_name = | strat_name = | formality = | alternate_spellings = | synonym1 = | synonym1_coined = | synonym2 = | synonym2_coined = | synonym3 = | synonym3_coined = | former_names = | proposed_names = | celestial_body = moon | usage = | timescales_used = Lunar Geologic Timescale | used_by = | formerly_used_by = | not_used_by = | chrono_unit = Period | strat_unit = | proposed_by = | lower_boundary_def = | lower_stratotype_location = | upper_boundary_def = | upper_stratotype_location = | o2 = | co2 = | temp = | sea_level = The pre-Nectarian period of the lunar geologic timescale runs from 4.533 billion years ago (the time of the initial formation of the Moon) to 3.920 billion years ago, when the Nectaris Basin was formed by a large impact. It is followed by the Nectarian period.
Description
Pre-Nectarian rocks are rare in the lunar sample suite; they are mostly composed of lunar highlands material which have been heavily churned, brecciated, and thermally affected by subsequent impacts, particularly during the Heavy Bombardment Eon (HBE; a period of 0.6-1 Gy from the formation of the Moon until at least the formation of the Imbrium Basin ~3.9 Ga, or even later with the formation of Orientale Basin) that marks the approximate beginning of the Nectarian period. The primary pre-Nectarian lunar highland material is dominated by the rock type anorthosite, which suggests that the early stage of lunar crustal formation occurred via mineral crystallization of a global magma ocean.
This geologic period has been informally subdivided into the Cryptic Era (4.533 - 4.172 Ga ago) and Basin Groups 1-9 (4.172 - 3.92 Ga ago), but these divisions are not used on any geologic maps. Similarly the later period has also been called the Aitkenian period.
Impact basins
| ::data[format=table]
| Apollo | 505 |
|---|---|
| :: |
|- |style="text-align:left;vertical-align:top;padding-left: 2em;"| For basins with no article, the two prominent craters' names are separately linked to their respective articles. |- |style="text-align:left;vertical-align:bottom;padding-left: 2em;"| Names of proposed basins are italicized. |}
References
References
- Fernandes V. A., Fritz J., Weiss B., Garrick-Bethel and Shuster D. (2013) The bombardment history of the Moon as recorded by 40Ar-39Ar chronology. Meteor. and Planet. Sci. 48, 241–269. DOI: 10.1111/maps.12054.
- Fritz J., Bitsch B., Kührt E., Morbidelli A., Tornow C., Wünnemann K., Fernandes V.A., Grenfell L.J., Rauer H., Wagner R. and [[Stephanie C. Werner. Werner S.C.]] (2014) Earth-like habitats in planetary systems. Planetary and Space Science 98, 254–267. https://dx.doi.org/ 10.1016/j.pss.2014.03.003i
- Don Wilhelms. (1987). "Geologic History of the Moon". U.S. Geological Survey Professional Paper 1348.
::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::