(Fig. 1) Stable carbon and oxygen isotope ratios of foraminifera of ODP Hole 113-690B

A remarkable oxygen and carbon isotope excursion occurred in Antarctic waters near the end of the Palaeocene (~57.33 Myr ago), indicating rapid global warming and oceanographic changes that caused one of the largest deep-sea benthic extinctions of the past 90 million years. In contrast, the oceanic plankton were largely unaffected, implying a decoupling of the deep and shallow ecosystems. The data suggest that for a few thousand years, ocean circulation underwent fundamental changes producing a transient state that, although brief, had long-term effects on environmental and biotic evolution.在约5733万年前、古新世（Palaeocene）末期附近的南极海域，曾发生一次显著的氧碳同位素偏移（oxygen and carbon isotope excursion）事件，该事件指示了快速全球变暖与海洋环境变化，并引发了过去9000万年间规模最大的深海底栖生物灭绝事件之一。与之形成鲜明对比的是，海洋浮游生物基本未受波及，这表明深浅层海洋生态系统出现了解耦现象。数据显示，在数千年的时间尺度内，海洋环流发生了根本性变革，形成了一种瞬态状态；尽管该状态持续时长有限，却对环境与生物演化产生了长期影响。