Distribution characteristics and paleo-climatic significance of continental climate-sensitive sediments in the Late Cretaceous in China
XU Bin, XIANG Fang, LI Shuxia
华北科技学院 河北省矿井灾害防治重点实验室成都理工大学 油气藏地质及开发工程国家重点实验室中国矿业大学(北京) 地球科学与测绘工程学院
白垩纪是研究温室气候、地球系统相互作用的典范时期,该时期全球最大的陆相地层主要出露在东亚地区尤其是中国,而当前基于陆相气候敏感性沉积物的组合特征来研究中国晚白垩世古气候的甚少。为获得中国晚白垩世古气候特征,通过详细分析晚白垩世早中晚3期不同陆相气候敏感性沉积物类型的分布特征,重建不同时期古气候类型。根据陆相气候敏感性沉积物类型及分布组合特征,划分出7种气候类型:暖湿–暖干、热干、热干–干旱、热干–半干旱、热干–热湿、干热–暖湿及热干–暖干气候。研究表明:晚白垩世早期,热干带分布最广,其次为暖湿–暖干气候带;晚白垩世中晚期,热干气候带范围逐渐变广,且从中期以后,热干气候带东西贯通,横亘整个新疆和中国东部;热干–半干旱气候带呈NW—SE近纬度分布,从新疆西部一直延伸到江西及福建地区,显示出干旱化程度进一步加强。全球地质事件、古地理特征及区域构造演化对中国晚白垩世的古气候有重大影响,如:全球火山的喷发事件导致中国晚白垩世早期的温度升高;中国东南沿海山脉导致中国南部地区晚白垩世气候变干;雪峰山、武陵山脉、南岭和太行山是晚白垩世早期热干带与热干–干旱气候带的分界线,阿尔金山是晚白垩世中期中国西部地区热干气候带东南段的分界线。
The Cretaceous is a typical period for studying the greenhouse climate and the earth system interactions, and the world's most extensive terrestrial strata are mainly in East Asia, especially in China. Continental sediments can effectively reflect the paleoclimate change, but the previous studies of the Late Cretaceous paleoclimate, based on the combined characteristics of continental climatesensitive sediments, were barely found in China. To obtain the Late Cretaceous paleoclimate characteristics of China, the distribution characteristics of different continental climate-sensitive sediment types in the early, middle and Late Cretaceous in China were studied in detail.According to the distribution and combination characteristics and types of continental climate-sensitive sediments, seven climate types can be divided: 1) warm-humid and warm-dry climate; 2) hot and dry climate; 3) hot-dry and arid climate; 4) hot-dry and semiarid climate; 5) hot-dry and hotwet climate; 6) hotdry and warmhumid climate; 7) hotdry and warmdry climate. The results show that in the early Late Cretaceous, the hot and dry climate was the most widespread, followed by warmhumid and warmdry climate, but the climate was drier than the paleoclimate of the previous study of Early Cretaceous. Hot and dry climate zone became wider in the Coniacian and Maastrichtian; furthermore, it covered Xinjiang to the east of China from east to west after the Santonian Period. The hotdry and semiarid climate zone was nearly latitudinally distributed from the northwest to the southeast and it shows a further increase in aridification. Global geological events, paleogeographic features and regional tectonic evolution had significant impacts on the paleoclimate of China in the Late Cretaceous, such as global eruptive events of volcanoes led to the temperature increase in China in the early Late Cretaceous; coastal mountain ranges in southeastern China led to the drying of the Late Cretaceous climate in southern China; Xuefeng Mountains, Wuling Mountains, Nanling Mountains and Taihang Mountains were the dividing line between the hot and dry climate zone and hotdry and arid climate zone in the early Late Cretaceous, and Altun Mountains were the dividing line between the southeastern section of the hot and dry climate zone in western China in the middle Late Cretaceous.
Late Cretaceous; continental; climate-sensitive sediments; China; climate type; influence factor
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会