Exposure histories of the lunar meteorites: MAC88104, MAC88105, Y791197, and Y86032

Conference · Fri Nov 01 04:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (United States)

OSTI ID:5142642

Vogt, S; Herzog, G F ^[1]; Fink, D; Klein, J; Middleton, R ^[2]; Dockhorn, B; Korschinek, G; Nolte, E ^[3]

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1. Rutgers, The State Univ. of New Jersey, New Brunswick (United States)
2. Univ. of Pennsylvania, Philadelphia (United States)
3. Technische Univ. Muenchen, Garching (West Germany)

Four lunar meteorites, MacAlpine Hills (MAC) 88104, MacAlpine Hills 88105, Yamato (Y) 791197, and Yamato 86032 were analyzed for the cosmogenic radionuclides {sup 10}Be, {sup 26}Al, {sup 36}Cl, and {sup 41}Ca. From these and published data, histories of exposure to cosmic rays were modeled in terms of two-stage irradiations each with a long first stage on the Moon lasting a time T{sub 2{pi}} > 5 Ma at a burial depth d{sub 2{pi}}(g/cm{sup 2}) followed by a second stage in space, i.e., the transit time between the Moon and Earth, lasting a time T{sub 4{pi}} (Ma) in a body of typical meteoroidal size. The terrestrial age T{sub t} (Ma) gives the time elapsed between meteorite fall and recovery in Antarctica. The following sets of parameters were obtained: MAC88104/5, 390 {le} d{sub 2{pi}} {le} 500, 0.04 {le} T{sub 4{pi}} {le}0.11, 0.10 {le} 0.19; Y791197, D{sub 2{pi}} < 80, T{sub 4{pi}} < 0.1, T{sub t} < 0.1; Y86032, D{sub 2{pi}} > 1000, T{sub 4{pi}} = 10 {plus minus} 2, 0.08 < T{sub t} < 0.12. From the number and exposure histories of lunar meteorites the authors infer a production rate on the order of 5 Ma{sup {minus}1} and an arrival rate worldwide of about 3 {times} 10{sup 6} meteorites Ma{sup {minus}1}. These results suggest that each impact event large enough to produce lunar meteorites sends a large number of them to the Earth.

• OSTI ID: 5142642
• Report Number(s): CONF-9003166--
• Conference Information: Journal Name: Geochimica et Cosmochimica Acta; (United States) Journal Volume: 55:11
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ALKALINE EARTH ISOTOPES
ALUMINIUM 26
ALUMINIUM ISOTOPES
BERYLLIUM 10
BERYLLIUM ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
CALCIUM 41
CALCIUM ISOTOPES
CHEMICAL COMPOSITION
CHLORINE 36
CHLORINE ISOTOPES
COSMIC RADIATION
ELECTRON CAPTURE RADIOISOTOPES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOLOGIC HISTORY
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPE DATING
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
LUNAR MATERIALS
MATERIALS
METEORITES
NUCLEI
ODD-ODD NUCLEI
PETROGENESIS
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
YEARS LIVING RADIOISOTOPES