Paleoenvironmental change during greenhouse periods spanning 65Ma

在这项研究中，我们专注于65米的温室期间的古环境和生物相的变化。你...温室的第一个时期是中白垩纪（Aptian到Turonian），当时热带到亚热带的珊瑚和有孔虫物种发生了向极的分布。在大陆架和深海环境中记录了5次以富含有机质的海洋黑泥为标志的缺氧事件，表明海洋环流停滞。相反，晚白垩世（Coniacian到Maastrichtian）则显示气候相对较冷。古新世晚期高温峰期（LPTM）是古新世晚期高温峰期的第二个阶段。我们在这里认识到底栖生物灭绝事件（BEE），其特征是从古新世的组合，包括好氧和eutoropic始新世缺氧和寡营养的动物湍流。然而，在LPTM期间没有发生显著的反渗透有孔虫的周转。这些暖事件是由于脊系统/超级羽流的强烈火山活动释放的温室气体增加造成的。

In this study, we focused on changes of paleoenvironments and biofacies during greenhouse periods spanning 65 m. y.. The first period of greenhouse is the middle Cretaceous (Aptian to Turonian) when polarward distributions of tropical to subtropical species of corals and foramminifers occurred. Some five anoxic events marked by marine black muds containing abundant organic matters had been recorded on both continental shelf and deep marine environments, suggesting stagnation of ocean circulations. In contrasts, the late Cretaceous (Coniacian to Maastrichtian) indicates relatively cooler climate. The turnover age from hot to cool climates was bout 90 Ma.The second period is the Late Paleocene Themal Maximum (LPTM). We recognized here the benthic extinction event (BEE) which is characterized by a faunal turmover from Paleocene assemblage consisting of oxic and eutoropic to Eocene anoxic and oligotropjic ones. However, no remarkable turnovers of planktonic foraminifers occurred during LPTM. These warm events resulted from the increase of greenhouse gasses released by intense volcanic activity of ridge systems/superplumes.