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Implications Of Hf-Nd Isotopes In West Philippine Basin Basalts For The Initiation And Early History Of The Izu-Bonin-Mariana Arc, Benjamin D. Hocking
Implications Of Hf-Nd Isotopes In West Philippine Basin Basalts For The Initiation And Early History Of The Izu-Bonin-Mariana Arc, Benjamin D. Hocking
Theses and Dissertations
Drilling at Site U1438, located immediately west of Kyushu-Palau Ridge (KPR), the site of IBM subduction initiation, penetrated 1,460 m of volcaniclastic sedimentary rock and 150 m of underlying basement. Biostratigraphic controls indicate a probable age for the oldest sedimentary rocks at around 55 Ma. This is close to the 48-52 Ma time period of IBM subduction initiation, based on studies in the forearc. There, the first products of volcanism are tholeiitic basalts termed FAB (forearc basalt), which are more depleted than average MORB and show subtle indicators of geochemical enrichment due to subduction. Site U1438 basement basalts share many …