Radiogenic isotopic signatures in the deep South Pacific during the Early and Middle Pliocene@en

The dataset contains Nd isotope signatures (expressed as εNd) and Pb isotopic ratios (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) for IODP Expedition 383 Sites U1540 and U1541 measured in fish debris, foraminifera and bulk leachates. The data covers the Early and Middle Pliocene from 3.2 to 5.2 Ma BP. Additionally, lithogenic εNd, Pb isotopic ratios (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb), and Sr isotopic ratio (87Sr/86Sr) for the sortable silt fraction (<63 µm) for U1540 and U1541 are included. The obtained South Pacific εNd (authigenic) values for the Pliocene cover a range from εNd= -7.5 to -5.5 and with it are consistently more radiogenic than presently implying a changed deep water mass exchange. The authigenic Pb isotopic signatures lie in a range between 206Pb/204Pb=18.76 to 18.79 207Pb/204Pb=15.64 to 15.66 and 208Pb/204Pb= 38.70 to 38.78 and indicate changes in weathering input to the South Pacific.本数据集包含国际大洋发现计划（International Ocean Discovery Program, IODP）第383航次U1540与U1541站位中，于鱼骨骼残骸、有孔虫及整体浸提物内测得的钕同位素组成（以εNd表示）与铅同位素比值（206Pb/204Pb、207Pb/204Pb、208Pb/204Pb）。数据覆盖距今3.2至5.2 Ma BP的上新世早期与中期。此外，数据集还纳入了U1540与U1541站位可分选粉砂组分（粒径<63 µm）的陆源εNd、铅同位素比值（206Pb/204Pb、207Pb/204Pb、208Pb/204Pb）以及锶同位素比值（87Sr/86Sr）。本次测得的上新世南太平洋自生εNd值范围为εNd=-7.5至-5.5，其同位素放射性均高于现今值，指示深水水团交换过程发生改变。自生铅同位素组成的范围为206Pb/204Pb=18.76~18.79、207Pb/204Pb=15.64~15.66以及208Pb/204Pb=38.70~38.78，表明南太平洋的风化输入存在变化。