High-resolution seawater δ¹⁸O records, derived from coupled Mg/Ca and benthic δ¹⁸O analyses, can be used to evaluate how global ice volume changed during the mid-Pleistocene transition (MPT, ca. 1250–600 ka). However, such seawater δ¹⁸O records are also influenced by regional hydrographic signals (i.e., salinity) and changes in deep-ocean circulation across the MPT, making it difficult to isolate the timing and magnitude of the global ice volume change. To explore regional and global patterns in seawater δ¹⁸O records, we reconstruct seawater δ¹⁸O from coupled Mg/Ca and δ¹⁸O analyses of Uvigerina spp. at Ocean Drilling Program Site 1208 in the North Pacific Ocean. Comparison of individual seawater δ¹⁸O records suggests that deep-ocean circulation reorganized and the formation properties (i.e., salinity) of deep-ocean water masses changed at ca. 900 ka, likely related to the transition to marine-based ice sheets in Antarctica. We also find that an increase in ice volume likely accompanied the shift in glacial-interglacial periodicity observed in benthic carbonate δ¹⁸O across the MPT, with increases in ice volume observed during Marine Isotope Stages 22 and 16.

中文翻译：

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更新世中期过渡期间海水δ18 O记录中的区域和全球信号

高分辨率海水δ ^18所ö记载，从耦合的Mg / Ca和底栖δ衍生^18和ø分析，可以用来评估冰量如何全球中期更新世过渡（MPT，约1250-600 KA）期间改变。然而，这样的海水δ ^18个Ø记录也由区域水文信号（即盐度），并在整个MPT深层海洋环流变化的影响，因此很难在全球冰量变化的时间和幅度隔离。探索海水区域和全球图案δ ^18分ö的记录，我们重构海水δ ¹⁸ ö从耦合的Mg / Ca和δ ¹⁸O对Uvigerina spp的分析。在北太平洋海洋钻井计划1208号站点。个别海水δ的比较^18个ö记录表明该重组深海循环和深海水团的形成性质（即，盐度）在约改变 900 ka，可能与南极向海洋冰盖的过渡有关。我们还发现，增加在冰量可能伴随在冰-间周期性移位底栖碳酸盐观察δ ¹⁸横跨MPT O，与在海洋同位素阶段22和16观察到在冰量增加。