Calcareous plankton paleobiogeographic evidence for major climatic fluctuations in the early Cenozoic Atlantic Ocean
Calcareous plankton paleobiogeographic evidence for major climatic fluctuations in the early Cenozoic Atlantic Ocean
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新生代早期大西洋主要气候波动的钙质浮游生物古生物地理证据
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
G. P. Lohmann
中科院分区：
文献类型：
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作者：
B. Haq;I. Premoli;G. P. Lohmann
只有在深海钻探计划（DSDP）的出现和更广泛的新生代深海岩心材料的可用性，大规模的前第四纪古环境研究可以尝试使用海洋浮游生物。本研究是绘制新生代早期（65-24百万年）地图的首次尝试之一。B.P.）利用DSDP岩心研究大西洋钙质浮游生物的时空分布，并从结果模式重建该地区的古气候历史。本文根据定量组合描述了早新生代钙质微型浮游生物（球壳和盘壳）和浮游有孔虫的地理分布格局。这些模式表明：（1）除古新世早期（6500 ~ 6400万年）外，新生代早期的大部分时间里，钙质碳酸盐岩群之间存在着纬向分异; B.P.）当浮游有孔虫组合在所有纬度基本上是同质的，显示出很小的地方性，当微型浮游生物所表现出的植物区系梯度与近岸和开阔海洋条件更密切相关时，以及（2）这两个群体的分布格局发生了重大变化：那些与随时间的主要纬度变化有关的，以及那些由于各种形式的进化和消失。与现今海洋一样，新生代早期的模式被认为主要受纬度热梯度（气候）的控制。因此，在组合的时间振荡被解释为主要的气候波动所造成的。在新生代早期的大西洋中记录了四个显著的冷却事件：古新世中期（60-58百万年）。B.P.），始新世中期（46-43百万年）B.P.），最早的渐新世（37-35百万年）B.P.），渐新世中期（32-28百万年）。B.P.）。一个特别明显的变暖事件发生在古新世晚期-始新世早期（54-51百万年）。B.P.），第二个，不太突出的变暖趋势开始于最新的渐新世（2800万年）。B.P.）一直延续到中新世早期
It is only since the advent of the Deep Sea Drilling Project (DSDP) and the wider availability of older Cenozoic deep-sea core material that large-scale pre-Quaternary paleoenvironmental studies using marine microplankton could be attempted. The present study is one of the first attempts at mapping the early Cenozoic (65–24 m.y. B.P.) spatial and temporal distributions of calcareous plankton of the Atlantic Ocean using the DSDP cores and reconstructing the paleoclimatic History of the region from the resultant patterns. The early Cenozoic biogeographic patterns of calcareous nannoplankton (coccoliths and discoasters) and planktonic foraminifera have been delineated on the basis of quantitatively defined assemblages. These patterns show (1) that latitudinal differentiation among the calcareous planktonic groups existed during most of the early Cenozoic, with the exception of the earliest Paleocene (65–64 m.y. B.P.) when planktonic foraminiferal assemblages were essentially homogeneous through all latitudes, showing little provinciality, and when the floral gradients exhibited by nannoplankton were more closely related to near-shore and open ocean conditions and (2) that there have been major changes in the distributional patterns of both groups: those related to major latitudinal shifts with time and those due to evolution and disappearance of various forms. As is true in the present-day ocean, the early Cenozoic patterns are considered to be controlled mainly by the latitudinal thermal gradient (climate). Thus the temporal oscillations in the assemblages are interpreted as being caused by major climatic fluctuations. Four marked cooling episodes are recorded within the early Cenozoic Atlantic Ocean: those during the middle Paleocene (60–58 m.y. B.P.), the middle Eocene (46–43 m.y. B.P.), the earliest Oligocene (37–35 m.y. B.P.), and the middle Oligocene (32–28 m.y. B.P.). A particularly marked warming episode occurred during the late Paleocene-early Eocene (54–51 m.y. B.P.), and a second, less prominent warming trend began in the latest Oligocene (28 m.y. B.P.) and continued into the early Miocene.