(Table 1) Helium concentration in sediments

• Main Authors: Ozima, Minoru, Takayanagi, M, Zashu, S, Amari, Sachiko
• Format: Dataset
• Language: English
• Published: PANGAEA 1984
• Subjects: 43-386; 43-387; Deep Sea Drilling Project; Depth; bottom/max; sediment/rock; top/min; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Helium-3; standard deviation; Helium-3/Helium-4; Helium-4; 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; Pacific; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.770039; https://doi.org/10.1594/PANGAEA.770039

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.