金丁剖面MIS3阶段黄土地层记录的温湿气候特征初步研究

通过对黄土高原中北部金丁镇马兰黄土中磁化率、Rb/Sr、全铁含量(TFe)与化学蚀变指数(CIA)等气候指标测试分析,并结合光释光年代学数据,着重地探讨了金丁剖面黄土地层记录的MIS3阶段气候变化特征。研究表明,金丁剖面MIS3阶段总体气候特征温湿,冷暖气候频繁波动,可进一步划分为5个阶段:51.6~44.9ka B.P.,弱温湿;42.0~39.9ka B.P.,中等温湿;37.4~27.8ka B.P.,相对强温湿;以及44.9~42.0ka B.P.和39.9~37.4ka B.P.两个冷干期。金丁剖面MIS3温湿气候成因机制的初步探讨认为北半球太阳辐射量增加导致的增温作用更直接,而高纬驱动与低纬过程耦合作用机制尚待开展进一步研究工作。

A Preliminary Study on Characteristics of Warm and Humid Climate of Loess of Jinding Section During MIS3

By the systematic measurement and analysis of magnetic susceptibility, Rb/Sr ratio, total Fe content (TFe), chemical index of alteration (CIA) and OSL dating data of the Jinding malan loess in the north-central Loess Plateau, and the paleoclimate change of the Jinding section during Marine Isotope Stage (MIS)3 are discussed. Results indicate that the general characteristics of paleoclimate change of the Jinding section during MIS3 are relatively warm and humid with the cold and warm climatefluctuation, which could include 5 stages, 51.6-44.9 ka B.P., a relatively week warm and humid climate interval; 42.0-39.9 ka B.P., a warm and humid climate interval;37.4-27.8 ka B.P., a relatively strong warm and humid climate interval;44.9-42.0 ka B.P. and 39.9-37.4 ka B.P., dry and cold climate intervals. The formation mechanism of the climate change during MIS3 in Jinding suggests that the increasing solar radiation of the northern hemisphere leads to the warming effect more directly, but the coupling mechanism by a high latitude forcing and tropic driving factors remains to be further research.