基于共存分析法和叶缘分析法重建中国渐新世年均温  

Quantitative Reconstruction of Oligocene Mean Annual Temperatures in China based on Coexistence Approach and Leaf Margin Analysis

作　　者：王秋军[1] 毛铁 孙柏年 马福军 吴步青 夏燕梅 刘松 

机构地区：[1]贵州大学资源与环境工程学院贵州省古生物研究中心,贵阳550025 [2]贵州正业工程技术投资有限公司,贵阳550005 [3]兰州大学地质科学与矿产资源学院,兰州73000 [4]贵州师范学院地理与旅游学院,贵阳550018 [5]黔东南苗族侗族自治州地质公园管理局,贵州凯里556000

出　　处：《地质学报》2017年第12期2608-2622,共15页Acta Geologica Sinica

基　　金：国家自然科学基金(编号:41172022);贵州省古生物研究中心建设基金(编号:黔科合计Z字\[2014\]4003号);贵州师范学院科研基金项目(编号:2015BS014);贵州大学引进人才科研项目(编号:贵大人基合字(2015)35号)资助的成果

摘　　要：渐新世全球气候总体上发生了降温,代表着地球新生代早期的一个"冰室"。植物对气候变化反应敏感,作为地质时期的产物,植物化石能够反映当时陆地气候的变迁。本文利用共存分析法(Coexistence Approach,CA)对中国5个渐新世植物群的年均温进行了恢复,并利用叶缘分析法(Leaf Margin Analysis,LMA)对其中木本双子叶植物不少于15种的4个植物群年均温进行了分析。两类方法的推测值整体表现为CA的年均温相对高于LMA值,其中叶缘分析法东亚模型得出的年均温高于中国模型值。通过对能影响两类方法结果的因素分析,推测CA恢复的值能更好地代表化石点当时的年均温,咸水河组下段植物群为13.3~15.6℃,杨连屯组大桥段植物群为12.1~19.4℃,三合植物群为14.3~16.8℃,景谷植物群为19.7~23.7℃,宁明组植物群为22.0~23.6℃。由于CA恢复的年均温都高于当地现在的年均温,推测渐新世时,虽然全球温度自始新世以来整体相对降低,但还是比现在温暖。The Oligocene is characterized by gradually global cooling and represents an early “icehouse” epoch during the Cenozoic. The plant fossils, as the record of geological time, can reflect the climate change of continents at that period. In this study, the Mean Annual Temperatures （MATs） of five Oligocene floras in China were reconstructed using Coexistence Approach （CA） and the MATs of four floras with no less than 15 woody dicotyledonous taxa were analyzed using Leaf Margin Analysis （LMA）. Estimated MATs were consistent with the palaeoclimate indicated by the taxa of these palaeofloras. LMA gives consistently lower MAT predictions than these of CA, while MATs derived from the East Asian LMA model are consistently higher than that derived from the Chinese LMA model. Through analysis of the factors affecting the results of two methods, CA based MAT can better represent the annual temperatures at fossil locations then, with 133-156 ℃ for the palaeoflora of the lower member of the Xianshuihe Formation, 121-194 ℃ for the palaeoflora of the Daqiao member of the Yangliantun Formation, 143-168 ℃ for the Sanhe palaeoflora, 197-237 ℃ for the Jinggu palaeoflora and 220-236 ℃ for the Ningming palaeoflora, respectively. Due to the fact that the annul temperatures restored using CA were higher than present ones, it can be inferred that global temperatures have been relatively lower since the Oligocene, but warmer than that today.

关 键 词：年均温 共存分析法 叶缘分析法 植物化石 渐新世 

分 类 号：Q914[天文地球—古生物学与地层学]