Sr, Nd and Pb isotopic ratios of igneous rocks from DSDP holes (Table 1)@en
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Igneous rocks from the Philippine tectonic plate recovered on Deep Sea Drilling Project Legs 31, 58 and 59 have been analyzed for Sr, Nd and Pb isotope ratios. Samples include rocks from the West Philippine Basin, Daito Basin and Benham Rise (40-60 m.y.), the Palau-Kyushu Ridge (29-44 m.y.) and the Parece Vela and Shikoku basins (17-30 m.y.). Samples from the West Philippine, Parece Vela and Shikoku basins are MORB (mid-ocean ridge basalt)-like with 87Sr/86Sr = 0.7026 - 0.7032, 143Nd/144Nd = 0.51300 - 0.51315, and 206Pb/204Pb = 17.8 - 18.1. Samples from the Daito Basin and Benham Rise are OIB (oceanic island basalt)-like with 87Sr/86Sr = 0.7038 - 0.7040, 143Nd/144Nd = 0.51285 - 0.51291 and 206Pb/204Pb = 18.8 - 19.2. All of these rocks have elevated 207Pb/204Pb and 208Pb/204Pb compared to the Northern Hemisphere Regression Line (NHRL) and have delta207Pb values of 0 to +6 and delta208Pb values of +32 to +65. Lavas from the Palau-Kyushu Ridge, a remnant island arc, have 87Sr/86Sr = 7032 - 0.7035, 143Nd/144Nd = 0.51308 - 0.51310 and 206Pb/204Pb = 18.4 - 18.5. Unlike the basin magmas erupted before and after them, these lavas plot along the NHRL and have Pb-isotope ratios similar to modern Pacific plate MORB's. This characteristic is shared by other Palau-Kyushu Arc volcanic rocks that have been sampled from submerged and subaerial portions of the Mariana fore-arc. […]
本数据集针对深海钻探计划（Deep Sea Drilling Project）第31、58、59航次采自菲律宾构造板块的火成岩，开展了锶（Sr）、钕（Nd）与铅（Pb）同位素比值测试分析。本次分析的样品涵盖西菲律宾海盆、大东盆地与班哈姆高地（40~60百万年）、帕劳-九州海脊（29~44百万年）以及帕雷塞-韦拉海盆与四国海盆（17~30百万年）的火成岩。西菲律宾海盆、帕雷塞-韦拉海盆与四国海盆的样品类洋中脊玄武岩（mid-ocean ridge basalt, MORB），其87Sr/86Sr比值范围为0.7026~0.7032，143Nd/144Nd比值范围为0.51300~0.51315，206Pb/204Pb比值范围为17.8~18.1。大东盆地与班哈姆高地的样品类洋岛玄武岩（oceanic island basalt, OIB），其87Sr/86Sr比值范围为0.7038~0.7040，143Nd/144Nd比值范围为0.51285~0.51291，206Pb/204Pb比值范围为18.8~19.2。所有上述岩石的207Pb/204Pb与208Pb/204Pb比值均高于北半球回归直线（Northern Hemisphere Regression Line, NHRL），其δ207Pb值范围为0~+6，δ208Pb值范围为+32~+65。作为残余岛弧的帕劳-九州海脊产出的熔岩，其87Sr/86Sr比值范围为7032~0.7035，143Nd/144Nd比值范围为0.51308~0.51310，206Pb/204Pb比值范围为18.4~18.5。与前后喷发的盆地岩浆不同，这些熔岩的同位素数据点均落在NHRL线上，其铅同位素比值与现代太平洋板块洋中脊玄武岩相近。该特征同样见于马里亚纳前弧水下与出露部分采集的其他帕劳-九州岛弧火山岩。[……]
