Cousens, Brian L; Allan, James F (1992): (Table 1) Isotopic and trace-element composition of ODP Leg 127/128 basalts [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.777123, Supplement to: Cousens, BL; Allan, JF (1992): A Pb, Sr, and Nd isotopic study of basaltic rocks from the Sea of Japan, Legs 127/128. In: Tamaki, K; Suychiro, K; Allan, J; McWilliams, M; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 127/128(2), 805-817, https://doi.org/10.2973/odp.proc.sr.127128-2.199.1992
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Abstract:
The western Pacific includes many volcanic island arc and backarc complexes, yet multi-isotopic studies of them are rare. Basement rocks of the Sea of Japan backarc basin were encountered at Sites 794,795, and 797, and consisted of basaltic sills and lava flows. These rocks exhibit a broad range in isotopic composition, broader than that seen in any other western Pacific arc or backarc system: 87Sr/86Sr = 0.70369 to 0.70499, 143Nd/144Nd = 0.51267 to 0.51317, 206Pb/204Pb = 17.64 to 18.36. The samples form highly correlated arrays between very depleted mid-ocean ridge basalt (MORB) and the Pacific pelagic sediment fields on Pb-Pb plots. Similarly, on plots of Sr-Pb and Nd-Pb, the Sea of Japan samples lie on mixing curves between depleted mantle and enriched mantle ("EM II"), which is interpreted to be of average crustal or pelagic sediment composition. The source of these backarc rocks appears to be a MORB-like mantle source, contaminated by pelagic sediments. Unlike the Mariana and Izu arc/backarc systems, Japanese arc and backarc rocks are indistinguishable from each other in a Sr-Nd isotope plot, and have similar trends in Pb-Pb plots. Thus, sediment contamination of the mantle wedge appears to control the isotopic compositions of both the arc and backarc magmas. Two-component mixing calculations suggest that the percentage of sediments in the magma source varies from 0.5% to 2.5%.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 40.745600 * Median Longitude: 137.491100 * South-bound Latitude: 38.616000 * West-bound Longitude: 134.536000 * North-bound Latitude: 43.987000 * East-bound Longitude: 138.965000
Date/Time Start: 1989-07-03T20:30:00 * Date/Time End: 1989-09-29T23:00:00
Minimum Elevation: -3310.0 m * Maximum Elevation: -2818.0 m
Event(s):
127-794C * Latitude: 40.190000 * Longitude: 138.231000 * Date/Time Start: 1989-07-03T20:30:00 * Date/Time End: 1989-07-11T11:00:00 * Elevation: -2820.0 m * Penetration: 653.7 m * Recovery: 33.21 m * Location: Japan Sea * Campaign: Leg127 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 14 cores; 93.9 m cored; 0 m drilled; 35.4 % recovery
127-795B * Latitude: 43.987000 * Longitude: 138.965000 * Date/Time Start: 1989-07-16T00:00:00 * Date/Time End: 1989-07-22T02:45:00 * Elevation: -3310.0 m * Penetration: 762.2 m * Recovery: 188.94 m * Location: Japan Sea * Campaign: Leg127 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 41 core; 397 m cored; 0 m drilled; 47.6 % recovery
127-797C * Latitude: 38.616000 * Longitude: 134.536000 * Date/Time Start: 1989-08-04T17:00:00 * Date/Time End: 1989-08-18T17:00:00 * Elevation: -2876.0 m * Penetration: 900.1 m * Recovery: 164.18 m * Location: Japan Sea * Campaign: Leg127 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 45 cores; 416.1 m cored; 0 m drilled; 39.5 % recovery
Comment:
Trace-element concentrations uncertainty of ± 1%. Uncertainties: Sr and Nd ± 0.00002, 208Pb/204Pb ± 0.030, 206Pb/204Pb and 207Pb/204Pb ± 0.020.
Parameter(s):
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
155 data points