晋北中新世汉诺坝玄武岩中木化石的发现及其古气候意义

首次在晋北中新统汉诺坝玄武岩沉积夹层中发现了木化石。通过木化石的沉积环境分析,认为其为洪积扇上发育的辫状河道环境。对树木高度进行了估算,结果表明其为中等高大的乔木。结合前人对中新世中国北方孢粉、古植物、哺乳动物化石等的分析认为,中中新世晋北左云一带处于湿润的森林,且已向较干旱的疏林草原环境过渡,季节性降水导致的洪水携带大量砂砾将平缓地带的乔木迅速埋藏。这一发现,对于研究中新世时中国北方古气候变化及植物地理区系演化具有重要意义。

The discovery of fossil woods in Miocene Hannuoba basalt in northern Shanxi Province and its paleoclimate significance

Fossil woods were discovered recently in sedimentary intercalation in Miocene Hannuoba basalt in northern Shanxi Province. Primary analysis indicates that the sedimentary environment of these fossil woods belonged to braided channels developed on proluvial fan, and the estimation of tree heights shows that they belongs to averagely tall arbor.Combined with palynological assemblage,paleobotany and mammal fossils, the authors inferred a landscape of moist forest with trend of transition to arid sparse forest steppe, in which sand-gravel mixtures were rapidly carried to lowland by floods caused by seasonal precipitation, and hence these arbors were buried and petrified rapidly.