par Bibron, Roland;Leger, G.;Chesselet, Roger;Crozaz, Ghislaine 
;Mennessier, Jean Paul ;Picciotto, Edgardo
Référence Earth and planetary science letters, 21, 2, page (109-116)
Publication Publié, 1974
;Mennessier, Jean Paul ;Picciotto, Edgardo Référence Earth and planetary science letters, 21, 2, page (109-116)
Publication Publié, 1974
Article révisé par les pairs
| Résumé : | The reasons why 53Mn (a cosmogenic radionuclide with a half-life of 3.7 × 106 y) appears as one of the best indicators of the presence of interplanetary dust are summarized. This paper reports the detection of 53Mn in pre-1952 snow samples collected on the Eastern Antarctic Plateau in the vicinity of Plateau Station. The measurements were carried out by neutron activation and X-ray spectrometry on three samples weighing a few hundred kg and covering each the time interval 1935-1950. The specific activity of 53Mn was found to be (0.82 ± 0.17) disint.min-1/103 tons of snow, corresponding to a deposition rate at Plateau Station of (2.2 ± 0.5) × 10-5 disint. min-1 m-2 y-1. The mean global deposition rate would be three times higher if 53Mn were assumed to behave in the same way as stratospheric 90Sr. By comparing this figure with existing data on the meteorite flux reaching the earth and with the galactic and solar production rates of 53Mn, it is concluded that the bulk of the 53Mn found at Plateau Station is associated with interplanetary dust in which it had been produced by the action of solar protons on iron. The deposition rate of extra-terrestrial dust-borne iron must be between 1.3 × 10-5 and 1.3 × 10-4 g m-2 y-1 at Plateau Station. These results support jointly with other studies the concept of an interplanetary zodiacal cloud of dust with a chemical composition and density not essentially different from chondritic meteorites, with a relatively 'flat' grain size distribution and a mass influx to the earth of the order of 105 tons/y. © 1974. |
