山东济阳坳陷古近纪的气候恢复

Recovery of Climate of Palaeogene in Jiyang Depression of Shandong

首先根据孢粉母体植物对气温的适应性,将孢粉分为喜热组、喜温组和广温组,根据对湿度的适应性,分为湿生组、旱生组和中生组。然后计算出济阳坳陷古近系沙河街组和东营组反映温度比值和反映湿度比值,从而恢复各沉积时期的气候。研究表明,济阳坳陷从沙四段至东营组沉积时期经过了两个气候变化周期。第一个周期是始新世时期,湿度上:干旱→湿润,温度上:温凉→温→热→温;第二个周期是渐新世时期,湿度上:干旱→湿润→干旱,温度上:温→热→温→温凉。

Firstly, depending on the adaptability of sporopollen's parent-plants to the temperature, the spore and pollen can be divided into the hythermophilic type, thermophilic type and eurthermal type. Depending on the adaptability to the humidity, they can be divided into the humid type, dry type and media type. Secondly, the Ratio of Temperature (RT) and the Ratio of Humidity (RH) are calculated in Shahejie Formation and Dongying Formation (Palaeogene) of Jiyang Depression, and the climate of every sedimentary period is recoverd. The study shows that two climate cycles underwent from the sedimentary period of Shahejie Formation to that of Dongying Formation. The first cycle is in Eocene. The humidity changed from dry to humid, and the temperature from warm-cool, warm, hot to warm. The second cycle is in Oligocene. The humidity changed from dry, humid to dry, and the temperature from warm, hot, warm to warm-cool.