NOAA/WDS Paleoclimatology - Cape Basin Authigenic Nd and Benthic Stable Isotope Data for the Mid-Pleistocene Transition

The mid-Pleistocene transition (MPT) [~1.25 to 0.85 million years ago (Ma)] marks a shift in the character of glacial-interglacial climate. One prevailing hypothesis for the origin of the MPT is that glacial deep ocean circulation fundamentally changed, marked by a circulation “crisis” at ~0.90 Ma (marine isotope stages 24 to 22). Using high-resolution paired neodymium, carbon, and oxygen isotope data from the South Atlantic Ocean (Cape Basin) across the MPT, we find no evidence of a substantial change in deep ocean circulation. Before and during the early MPT (~1.30 to 1.12 Ma), the glacial deep ocean variability closely resembled that of the most recent glacial cycle. The carbon storage facilitated by developing deep ocean stratification across the MPT required only modest circulation adjustments.

中更新世转型（mid-Pleistocene transition, MPT）[约125万至85万年前（Ma，即百万年前）]标志着冰期-间冰期气候特征的转变。关于MPT的成因，目前主流假说认为冰期深海环流发生了根本性改变，以约90万年前（海洋同位素阶段24至22）的环流“危机”为标志。本研究利用采自南大西洋（开普盆地）、覆盖MPT时段的高分辨率配对钕、碳、氧同位素数据，未发现深海环流存在显著变化的相关证据。在MPT早期（约130万至112万年前）及此前，冰期深海环流变率与最近一次冰期旋回高度相似。中更新世转型期间，随深海层结发展所增强的碳储集，仅需要环流做出小幅调整即可实现。