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

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.

该数据集收录了IODP探险383号站U1540和U1541的Nd同位素特征（以εNd表示）及Pb同位素比值（206Pb/204Pb、207Pb/204Pb、208Pb/204Pb），这些特征是通过测量鱼粪、有孔虫及大量渗滤液获得。数据覆盖了早中新世至中中新世，时间跨度为3.2至5.2百万年前。此外，还包含了U1540和U1541站点的可分选细沙部分（<63 µm）的成岩εNd、Pb同位素比值（206Pb/204Pb、207Pb/204Pb、208Pb/204Pb）及Sr同位素比值（87Sr/86Sr）。所获得南太平洋地区的εNd（自生）值覆盖了εNd=-7.5至-5.5的范围，并且与现今相比，具有更高的放射性，这暗示了深层水团交换的变化。自生Pb同位素特征介于206Pb/204Pb=18.76至18.79、207Pb/204Pb=15.64至15.66及208Pb/204Pb=38.70至38.78之间，这表明对南太平洋的侵蚀物质输入发生了变化。