Miocene stable isotope stratigraphy of ODP Hole 120-747A

We correlated Miocene d18O increases at Ocean Drilling Program Site 747 with d18O increases previously identified at North Atlantic Deep Sea Drilling Project Sites 563 and 608. The d18O increases have been directly tied to the Geomagnetic Polarity Time Scale (GPTS) at Site 563 and 608, and thus our correlations at Site 747 provide a second-order correlation to the GPTS. Comparison of the oxygen isotope record at Site 747 with records at Sites 563 and 608 indicates that three as-yet-undescribed global Miocene d18O increases may be recognized and used to define stable isotope zones. The d18O maxima associated with the bases of Zones Mila, Milb, and Mi7 have magnetochronologic age estimates of 21.8, 18.3, and 8.5 Ma, respectively. […]本研究将大洋钻探计划（Ocean Drilling Program）747站位的中新世δ¹⁸O（d18O）值升高事件，与此前在北大西洋深海钻探计划（Deep Sea Drilling Project）563、608站位所识别的δ¹⁸O（d18O）值升高事件进行了关联对比。鉴于563与608站位的δ¹⁸O（d18O）值升高事件已直接锚定地磁极性年表（Geomagnetic Polarity Time Scale, GPTS），本次对747站位的关联分析可为地磁极性年表提供二级校正依据。通过将747站位的氧同位素记录与563、608站位的记录进行比对，可识别出3项尚未见报道的全球性中新世δ¹⁸O（d18O）值升高事件，此类事件可用于界定稳定同位素地层带。与Mila、Milb及Mi7三个地层带底界相伴生的δ¹⁸O（d18O）值峰值，其磁年代学年龄估算值分别为21.8、18.3及8.5 Ma。[…]