21世纪初，古新统/始新统界线（简称P/E界线）被国际地层委员会正式定义为古新世-始新世极热事件（简称PETM）期间碳同位素负漂的开始。然而，P/E界线在特提斯大有孔虫生物带（简称SBZ）中的具体位置却一直争论不休。本文回顾了国内外学者近二十年来对P/E界线的研究成果，认为P/E界线应该位于SBZ5的内部，而非SBZ4和SBZ5的界线处。在P/E界线处，大有孔虫没有发生明显的组分上的变化。而在P/E界线后的5—12万年内，大有孔虫发生了一次绝灭。这个绝灭事件被称为大有孔虫的绝灭和新生（简称LFEO）。大有孔虫的绝灭和新生不同于传统上认为的大有孔虫更替事件（简称LFT）。前者可能是由PETM后期强烈的陆地风化剥蚀引起海水富营养化后所造成的一次灾变事件，而后者代表了大有孔虫在长期稳定的浅海环境中形成的演化上的成功。通过回顾P/E界线的研究历史，笔者认为绝大部分地层剖面在P/E界线处的不连续性/不完整性是产生这些争议的主要原因。

In the beginning of the 21 century, the International Commission on Stratigraphy officially defined the Paleocene/Eocene (P/E) boundary as “the onset of carbon isotope excursion” during the Paleocene-Eocene thermal maximum (PETM). However, the topic where the P/E boundary is in the shallow benthic zonation (SBZ) is still in dispute. This paper reviews the last 20 years’ progresses on this topic, and concludes that the P/E boundary should be placed within SBZ5, not at the transition between SBZ4 and SBZ5 as traditionally thought. At the P/E boundary, no evident change in larger foraminiferal composition happens. Within the PETM-CIE recovery (about 50?120 kyr after the CIE onset), however, larger foraminifera experienced a drastic extinction. This extinction event was defined as larger foraminiferal extinction and origination. The larger foraminiferal extinction and origination event, in essence, differs from the larger foraminiferal turnover event. The former is likely caused by short-term seawater eutrophication that might have resulted from intensified continental weathering during the CIE recovery, while the latter represents an evolutionary success during the long-term stay in a stable environment. After reviewing previous studies on the P/E boundary, I think that discontinuity/incompleteness of many sedimentary sections close to the P/E boundary is the main cause for the dispute.

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