| Abstract: | The concentrations of uranium, thorium and lead and the lead isotopic composition of Luna 20 soil were determined. The data indicate that the Luna 20 soil is mainly a mixture of highland anorthosites and low-K basalt, but little KREEP basalt. The U-Th-Pb systematics are discussed in comparison with other lunar soils, especially with Apollo 16 soils which were collected from a ‘typical‘ highland region. The data fit well in the Apollo 16 soil array on a U-Pb evolution diagram, and they exhibit excess lead relative to uranium. This relationship appears to be a characteristic of highland localities. Considering the previous observations of lunar samples, we infer that lead enrichment in the soil relative to uranium occurred between 3.2 and 3.9 b.y. ago and that the soil was disturbed by ‘third events‘ about 2.0 b.y. ago. A lunar evolution model is discussed. ?? 1973. |
| Genre: | Article |
| ProdID: | 70010125 |
| Citation Author: | Tatsumoto, M. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 1086 |
| Citation Issue: | 4 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Geochimica et Cosmochimica Acta |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 8 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | U-Th-Pb measurements of Luna 20 soil; 1973; Article; Journal; Geochimica et Cosmochimica Acta; Tatsumoto, M. |
| Citation Start Page: | 1079 |
| Citation Volume: | 37 |
| Citation Year: | 1973 |
| Type: | citation/reference |
| Text: | U-Th-Pb measurements of Luna 20 soil; 1973; Article; Journal; Geochimica et Cosmochimica Acta; Tatsumoto, M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1973 00:00 -0600 |
| Publisher: | |
