Ozima, Minoru; Takigami, Yutaka (1980): Step-heating degassing data for argon-39 from volcanic rocks drilled in the Shikoku Basin and Mariana trench, DSDP Legs 58 and 60. PANGAEA, https://doi.org/10.1594/PANGAEA.706922, Supplement to: Ozima, M; Takigami, Y (1980): Activation energy for thermal release of Ar from some DSDP submarine rocks. Geochimica et Cosmochimica Acta, 44(1), 141-144, https://doi.org/10.1016/0016-7037(80)90185-4
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From the experimental data on stepwise thermal release of neutron induced 39Ar (39K (n, p) 39Ar) from rocks and minerals, Arrhenius plots were constructed, which gave activation energies for the thermal release process. The activation energies for DSDP Leg 58 and Leg 60 submarine volcanic rocks range from 12 to 20 kcal/mol, whereas those for granodiorites and the K-feldspar separates have activation energies ranging from 37 to 48 kcal/mol. The smaller activation energies for the submarine volcanic rocks reflect the grain boundary diffusion process, while the thermal diffusion of 39Ar from granodiorites and K-feldspar is essentially controlled by a volume diffusion. The grain boundary diffusion for the submarine volcanic rocks suggests that K resides essentially in the grain boundaries.
Median Latitude: 23.964133 * Median Longitude: 139.049867 * South-bound Latitude: 17.864200 * West-bound Longitude: 132.774800 * North-bound Latitude: 29.327500 * East-bound Longitude: 146.934300
Date/Time Start: 1977-12-28T00:00:00 * Date/Time End: 1978-04-18T00:00:00
58-443 * Latitude: 29.327500 * Longitude: 137.440500 * Date/Time: 1977-12-28T00:00:00 * Elevation: -4372.0 m * Penetration: 581.5 m * Recovery: 300 m * Location: North Pacific/BASIN * Campaign: Leg58 * Basis: Glomar Challenger * Device: Drilling/drill rig (DRILL) * Comment: 64 cores; 581.5 m cored; 0 m drilled; 51.6 % recovery
58-446A * Latitude: 24.700700 * Longitude: 132.774800 * Date/Time: 1978-01-18T00:00:00 * Elevation: -4952.0 m * Penetration: 628.5 m * Recovery: 117.5 m * Location: North Pacific/Philippine Sea/BASIN * Campaign: Leg58 * Basis: Glomar Challenger * Device: Drilling/drill rig (DRILL) * Comment: 28 cores; 256.5 m cored; 0 m drilled; 45.8 % recovery
60-458 * Latitude: 17.864200 * Longitude: 146.934300 * Date/Time: 1978-04-18T00:00:00 * Elevation: -3447.0 m * Penetration: 465.5 m * Recovery: 97.6 m * Location: North Pacific/TRENCH * Campaign: Leg60 * Basis: Glomar Challenger * Device: Drilling/drill rig (DRILL) * Comment: 46 cores; 437 m cored; 28.5 m drilled; 22.3 % recovery