摘要
白垩纪中期(125～90 Ma)是地质历史中一个极端温室时期,集中出现一系列异常事件.异常事件是地球系统内各圈层相互耦合的产物,事件相互之间不是孤立的,单个事件引起的全球变化对其他事件起着明显的正/负反馈机制作用.文中基于对白垩纪中期异常事件的深入解剖和分析,包括大规模海底火山事件、大洋缺氧事件、生物异常更替与绝灭、白垩纪超静磁带、大洋红层出现等,在探讨白垩纪中期各个事件特征基础上,重点阐述异常事件所引起的全球变化及其对海洋、气候的影响;提出异常事件之间的相互关联与反馈机制.研究发现,大规模海底火山作用是引起白垩纪中期异常海洋和气候的最根本原因,直接促进大洋缺氧事件、生物绝灭与更替、沉积记录的转变等事件的发生.
The Mid-Cretaceous (125~90 Ma) was one of the warmest greenhouse climate periods of the Phanerozoic, and was characterized by extraordinary igneous events, oceanic anoxia, biotic turnovers and mass extinctions, normal superchron, and oceanic red beds. These geological events were the results of the interactions between the lithosphere, the biosphere and the atmosphere. Each geological event would give rise to a special global change which would play an important role in engendering other events through a system of positive or negative feedbacks. This paper focuses on the introduction of these geological events, the global changes that they caused, and especially climate-ocean system. A special effort is given to the potential linkage and feedback mechanism of these geological events in the the Mid-Cretaceous. It is concluded that the igneous events, such as the emplacement of Large Igneous Provinces were the primary force to cause the abnormal ocean and greenhouse climate through outgas of CO_2, which would have further accelerated the formation of the oceanic anoxia, biotic mass extinctions, and a change in the nature of the sedimentary record.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2005年第2期222-230,共9页
Earth Science Frontiers
基金
国家自然科学基金资助项目(40302017
40332020)
联合国教育科学文化组织地球科学项目IGCP 494/463
关键词
白垩纪中期
异常事件
全球变化
大火成岩省
大洋缺氧
大洋红层
Mid-Cretaceous
abnormal geological events
global change
Large Igneous Provinces
oceanic anoxia
oceanic red beds
