【摘要】 通过对地处气候敏感带的岱海湖泊岩芯介形类壳体丰度、Sr/Ca和Mg/Ca摩尔比值,以及自生碳酸盐氧同位素组成等地球化学指标的综合分析,结合岩芯的岩性特征和210Pb、14C测年,重建了岱海小冰期以来气候环境演化过程,揭示小冰期前期本区以冷湿气候为主,在中后期,气候寒冷干旱,间有气候转温和的冷湿、温干气候。本区小冰期气温变化与华北其他地区具有一致性,但降水与气温组合状况复杂,反映了明显的区域特征,其原因可能是气候转型期经向环流加强,气旋活动加强所致。更多还原

【Abstract】 Located in the marginal belt of the southeast monsoon area, Daihai Lake, with a closed basin, is very sensitive to climate changes. Geochemical proxies, such as Sr/Ca and Mg/Ca ratios of the calcareous shells of ostracodes (Limnocythere cf. inopinata), oxygen isotope of lake authigenic carbonate in a sediments core from Daihai lake, have been employed in reconstructing the climatic processes during the Little Ice Age (LIA). The results showed the climate was characterized by cold wet in the early stage of LIA, cold dry climate with warm dry or cold wet fluctuation in the middle and latter stages. Two cold periods recorded by geochemical proxies were in good accordance with those deduced from the literature and ice core, indicating the changes of temperature in this area were similar to other areas in the North China. However, the combination of precipitation and temperature was more complicated, reflecting local character in the climate changes. The cold wet climate in the early LIA may result from the meridional circulation strengthening and the increase of cyclone activity.更多还原