| _version_ | 1867169038779547648 |
|---|---|
| author | Ozima, Minoru Takayanagi, M Zashu, S Amari, Sachiko |
| author_facet | Ozima, Minoru Takayanagi, M Zashu, S Amari, Sachiko |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Two decades ago, Merrihue (1964) reported 3He/4He ratios of >10**-4 in ferromagnetic separates from a Pacific deep ocean red clay and concluded that the high ratio is due to extraterrestrial debris amounting to ~1% of the sediment. A decade later Krylov et al. (1973) compiled 3He/4He isotopic data on ocean sediments measured in the Soviet Union and observed that the 3He/4He ratio is generally higher in pelagic sediments where the sedimentation rate is lower. They suggested that the high 3He/4He ratio was attributable to extraterrestrial materials which were concentrated in slowly accumulating ocean floor. However, these important discoveries were almost completely neglected until we re-examined the problem. We have measured 39 sediments from 12 different sites, 10 sites from the western to central Pacific and two sites from the Atlantic Ocean. We find 3He/4He ratios >5 * 10**-5 for six sites, well above the values generally observed in common terrestrial materials. The very high 3He/4He ratio in the sediments is probably due to input of extraterrestrial materials. Input of stratospheric dust of <1 p.p.m., which corresponds to a fallout rate of ~2,000 tons per year, can explain the observation. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_770039 |
| institution | PANGAEA |
| language | en |
| publishDate | 1984 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) Helium concentration in sediments Ozima, Minoru Takayanagi, M Zashu, S Amari, Sachiko 43-386; 43-387; Deep Sea Drilling Project; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Helium-3; Helium-3, standard deviation; Helium-3/Helium-4 ratio; Helium-3/Helium-4 ratio, standard deviation; Helium-4; Helium-4, standard deviation; KH68-4-15; KH68-4-18; KH68-4-20; KH75-3-11-2; KH75-3-5-2; KH80-3-18; KH80-3-22; KH80-3-22b; KH80-3-28; KH80-3-30; Leg43; North Atlantic/CONT RISE; North Pacific Ocean; PC; Piston corer; Sample code/label; Sample mass; South Pacific Ocean Two decades ago, Merrihue (1964) reported 3He/4He ratios of >10**-4 in ferromagnetic separates from a Pacific deep ocean red clay and concluded that the high ratio is due to extraterrestrial debris amounting to ~1% of the sediment. A decade later Krylov et al. (1973) compiled 3He/4He isotopic data on ocean sediments measured in the Soviet Union and observed that the 3He/4He ratio is generally higher in pelagic sediments where the sedimentation rate is lower. They suggested that the high 3He/4He ratio was attributable to extraterrestrial materials which were concentrated in slowly accumulating ocean floor. However, these important discoveries were almost completely neglected until we re-examined the problem. We have measured 39 sediments from 12 different sites, 10 sites from the western to central Pacific and two sites from the Atlantic Ocean. We find 3He/4He ratios >5 * 10**-5 for six sites, well above the values generally observed in common terrestrial materials. The very high 3He/4He ratio in the sediments is probably due to input of extraterrestrial materials. Input of stratospheric dust of <1 p.p.m., which corresponds to a fallout rate of ~2,000 tons per year, can explain the observation. |
| title | (Table 1) Helium concentration in sediments |
| topic | 43-386; 43-387; Deep Sea Drilling Project; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Helium-3; Helium-3, standard deviation; Helium-3/Helium-4 ratio; Helium-3/Helium-4 ratio, standard deviation; Helium-4; Helium-4, standard deviation; KH68-4-15; KH68-4-18; KH68-4-20; KH75-3-11-2; KH75-3-5-2; KH80-3-18; KH80-3-22; KH80-3-22b; KH80-3-28; KH80-3-30; Leg43; North Atlantic/CONT RISE; North Pacific Ocean; PC; Piston corer; Sample code/label; Sample mass; South Pacific Ocean |
| url | https://doi.org/10.1594/PANGAEA.770039 |