Ar40-Ar39 dating of Luna 16 and Luna 20 samples
Abstract
The Ar40-Ar39 isotope technique is used to determine the age of two fragments of Luna 16 mare basalt and two Luna 20 samples (one metaclastic fragment and a group of five anorthositic particles). The derived Luna 16 ages confirm that mare lavas were extruded in Mare Fecunditatis 3.4-3.5 billion years ago, and the age of the Luna 20 metaclastic fragment indicate a 3.9 billion year age for the Crisium basin and a widespread cataclysmic bombardment of the moon between 4.05 and 3.85 billion years. Analysis of Luna 20 anorthositic sample reveals a plateau age of 4.40 + or - 0.10 billion years and a minimum age of 4.30 + or - 0.10 billion years. Geologically, preference is given to interpretation of ancient highland ages in terms of a relatively small number of events.
- Publication:
-
Philosophical Transactions of the Royal Society of London Series A
- Pub Date:
- January 1977
- DOI:
- 10.1098/rsta.1977.0007
- Bibcode:
- 1977RSPTA.284..167C
- Keywords:
-
- Argon Isotopes;
- Basalt;
- Lunar Rocks;
- Petrology;
- Radioactive Age Determination;
- Selenology;
- Anorthosite;
- Lava;
- Lunik 16 Lunar Probe;
- Lunik 20 Lunar Probe;
- Tables (Data);
- Lunar and Planetary Exploration;
- ARGON ISOTOPES;
- BASALT;
- LUNAR ROCKS;
- PETROLOGY;
- RADIOACTIVE AGE DETERMINATION;
- SELENOLOGY;
- ANORTHOSITE;
- LAVA;
- LUNIK 16 LUNAR PROBE;
- LUNIK 20 LUNAR PROBE;
- TABLES (DATA)