地质论评2012，Vol.58Issue(1)：91-105,15.
始新世—渐新世气候转变研究进展
The Eocene-Oligocene Climate Transition: Review of Recent Progress
摘要
Abstract
The Eocene-Oligocene climate transition (EOCT) was a period of rapid global cooling at abou 34 Ma ago, representing a major step from early Cenozoic greenhouse toward modern icehouse conditions. It was accompanied by a series of dramatic changes in Earths environmental system, including an expansion of ice sheets on the Antarctic continent, a global sea-level drop, a declining atmospheric C02 concentration, a deepening of the calcite compensation depth, and a biotic reorganization, thus has great significance in understanding the mechanisms behind the long-term Cenozoic cooling, the behavior of regional climate in response to rapid cooling and the effects of major climatic changes on the biotic reorganization. This review summarizes recent progress in studying EOCT. (1) Significant cooling during this transition inferred from geological records of different latitudes indicates this phenomenon was triggered by global rather than regional factors. ( 2 ) The declining of atmospheric CO, and the associated global carbon cycle changes have been proved as the primary causes of EOCT by modeling studies, rather than the previous hypothesis that the Antarctica was thermally isolated by the initiation of Antarctic Circumpolar Current. (3) Marine records revealed that this transition is marked by a two-step increase of benthic foraminiferal oxygen isotope values occurred within 400 ~ 500 ka, reflecting the drop of global temperature and establishment of Antarctic ice sheets, respectively. (4) A comparison of the EOCT interval in Asian terrestrial records with marine records suggests that the regional aridification mainly corresponds to atmospheric cooling (i. e. , the first step of EOCT) rather than ice volume growth. However, there are still many questions remained unsolved. Future application of more detailed and accurate proxies of atmospheric C02 and paleotemperature, recovery of high-resolution sediment archives from the oceans and continents and more complex models across the EOCT will further reveal the changes of each environmental factor during this transition and their relationship with each other, and obtain a thorough understanding of the mechanisms behind this critical climate transition.关键词
始新世—渐新世气候转变/全球变冷/大气CO2/气候变化机制Key words
Eocene-Oligocene climate transition/ global cooling/ CO2/ mechanisms on climate change引用本文复制引用
肖国桥,张仲石,姚政权..始新世—渐新世气候转变研究进展[J].地质论评,2012,58(1):91-105,15.基金项目
本文为中国博士后科学基金(编号20110491234)、黄土与第四纪地质国家重点实验室开放基金(编号SKLLQG10286)、中国地质调查局项目(编号1212011121261)和生物地质与环境地质国家重点实验室开放基金(编号BGEG1010)共同资助的成果. （编号20110491234）
