Unknown
PANGAEA
In:
Supplement to: Parkinson, Ian J; Hawkesworth, Chris J; Cohen, Anthony S (1998): Ancient mantle in a modern arc: Osmium Iiotopes in Izu-Bonin-Mariana forearc peridotites. Science, 281(5385), 2011-2013, https://doi.org/10.1126/science.281.5385.2011
Publication Date:
2024-01-09
Description:
Mantle peridotites drilled from the Izu-Bonin-Mariana forearc have unradiogenic 187Os/188Os ratios (0.1193 to 0.1273), which give Proterozoic model ages of 820 to 1230 million years ago. If these peridotites are residues from magmatism during the initiation of subduction 40 to 48 million years ago, then the mantle that melted was much more depleted in incompatible elements than the source of mid-ocean ridge basalts (MORB). This result indicates that osmium isotopes record information about ancient melting events in the convecting upper mantle not recorded by incompatible lithophile isotope tracers. Subduction zones may be a graveyard for ancient depleted mantle material, and portions of the convecting upper mantle may be less radiogenic in osmium isotopes than previously recognized.
Keywords:
125-779A; 125-783A; 125-784A; Age model; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Gamma-Os; Joides Resolution; Leg125; North Pacific Ocean; Ocean Drilling Program; ODP; Osmium; Osmium-187/Osmium-188, error; Osmium-187/Osmium-188 ratio; Sample code/label; Sample comment
Type:
Dataset
Format:
text/tab-separated-values, 51 data points
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