Hf and Nd isotopic data of sediments from IODP LEG 113, Site 689D, Maud Rise, Antarctica

Sediment samples from IODP LEG 113 Site 689 Hole D (Maud Rise) sample the Eocene-Oligocene boundary (33.2 – 34.87 Ma). The objective is to elucidate the exact timing of the first glacial growth during the Eocene-Oligocene Transition (EOT; 34 Ma). The growth of the ice sheet could be inferred through the combination of Hf and Nd isotopes due to mechanical weathering of zircon that hosts relatively unradiogenic Hf. However, sediments transport can also bias the Hf isotopes in the marine sediments through size fractionation. We report here different size fractions of IODP Site 689 Hole D sediments for Hf-Nd isotopes and their trace element concentrations.采自国际大洋发现计划（International Ocean Discovery Program, IODP）第113航次689站位D孔（毛德海隆，Maud Rise）的沉积物样品，覆盖了始新世-渐新世界线（33.2–34.87 Ma）。本研究的目标是阐明始新世-渐新世过渡（Eocene-Oligocene Transition, EOT；34 Ma）期间首次冰川发育的确切时间。由于赋存相对非放射成因铪（Hf）的锆石发生机械风化，可通过铪（Hf）与钕（Nd）同位素的联合分析推断冰盖的发育过程。不过，沉积物搬运过程中的粒度分异作用也可能会对海洋沉积物中的铪同位素组成产生偏倚。本文报道了IODP 689站位D孔沉积物的不同粒度组分的铪-钕同位素及微量元素浓度数据。