Department of Geological Sciences and Environmental Studies, Binghamton University, Binghamton, New York, United States of America.
Department of Geosciences, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America.
PLoS One. 2020 Jul 15;15(7):e0234351. doi: 10.1371/journal.pone.0234351. eCollection 2020.
Planktic foraminiferal biostratigraphic zonation schemes are critical for providing first-order relative age control in deep-sea sediments and provide the basis on which to interpret evolutionary dynamics through time. Over the previous decades, the majority of published biostratigraphic zonation schemes focused on the tropical regions of the world. The mid-latitude or temperate regions, especially of the northwest Pacific, have been understudied in terms of recording plankton occurrences. Lack of detailed biostratigraphic studies have largely left out this region from plankton evolutionary analyses, thus how this part of the world ocean, which is characterized by the Kuroshio Current Extension (KCE), may contribute to global plankton biodiversity is unknown. In this study, we present the first magnetostratigraphically-calibrated late Neogene to Quaternary (15.12-0 Ma) planktic foraminiferal zonation schemes from the northwest Pacific for three Ocean Drilling Program Leg 198 holes (1207A, 1208A, and 1209A) that span the KCE. We utilize previously published warm subtropical, cool subtropical, and temperate zonation schemes from the southwest Pacific, with modifications. We find examples of significant diachroneity among primary marker taxa used to construct biozones at the three northwest Pacific sites, which ranges from 0.075 to 2.29 million years. Comparison of our primary datum markers with those of the tropical planktic foraminiferal zonation scheme also reveal diachroneity on the scale of 0.022 to 4.8 million years. We have identified times of intense dissolution in the northwest Pacific, namely in the middle to late Miocene that likely contribute to the observed diachroneity of datums. This study highlights the need for regionally specific mid-latitude biostratigraphic zonation schemes, as diachronous datums and differing assemblages may be hallmarks of oceanic ecotones created by major boundary current systems. These data also provide a framework to characterize local plankton evolutionary dynamics and paleobiogeographic patterns in future studies.
浮游有孔虫生物地层区划方案对于提供深海沉积物的一级相对年龄控制至关重要，并为随时间推移解释进化动态提供了基础。在过去的几十年中，大多数已发表的生物地层区划方案都集中在世界的热带地区。从中纬度或温带地区，特别是西北太平洋，在浮游生物出现方面的研究较少。缺乏详细的生物地层学研究在很大程度上使该地区无法进行浮游生物进化分析，因此，这个以黑潮延伸流（Kuroshio Current Extension，KCE）为特征的世界海洋部分如何为全球浮游生物多样性做出贡献尚不清楚。在本研究中，我们提出了西北太平洋三个大洋钻探计划第 198 航次（1207A、1208A 和 1209A）的最新近新生代至第四纪（15.12-0 百万年）的浮游有孔虫生物地层区划方案，这些方案经过了磁地层校准。我们利用了先前发表的来自西南太平洋的暖亚热带、凉亚热带和温带区划方案，并进行了修改。我们发现，在这三个西北太平洋站点构建生物带所使用的主要标志种存在显著的年代差异，范围从 0.075 到 2.29 百万年。将我们的主要基准标记与热带浮游有孔虫生物地层区划方案的标记进行比较，也揭示了在 0.022 到 4.8 百万年的范围内存在年代差异。我们已经确定了西北太平洋强烈溶解的时期，即在中到晚中新世，这可能导致基准标记的观测年代差异。本研究强调了需要制定区域性中纬度生物地层区划方案，因为年代不同的基准标记和不同的组合可能是由主要边界流系统形成的海洋生态过渡带的标志。这些数据还为未来研究提供了一个框架，以描述当地浮游生物进化动态和古生物地理模式。
