摘要
利用临夏塬堡剖面高分辨率的黄土记录,将研究剖面土壤地层界线,即剖面2.3m处的MIS1/2的分界线年龄11.5KaBP、剖面21.4m处的MIS3/4的分界线年龄59.8KaBP组成三种节点控制年龄模式,分界线年龄的获得依据南京葫芦洞石笋气候事件年龄确定,即模式1:0KaBP^59.8KaBP;模式2:0KaBP^11.5KaBP和11.5KaBP^59.8KaBP;模式3:11.5KaBP^59.8KaBP。运用磁化率年龄模型和粒度年龄模型分别计算研究剖面各个层位的地层沉积时间,结合剖面岩性和气候阶段对相同层位的计算年龄对比分析后发现:磁化率年龄模型和粒度年龄模型均存在缺陷,但以模式2作为节点控制年龄时,即在冰期或间冰期内选取合适的节点控制年龄,利用磁化率年龄模型或粒度年龄模型高分辨率确定的地层沉积时间与地层实际的沉积时间较接近,且在冰期或间冰期内节点控制年龄越多确定的地层沉积时间越趋近实际沉积时间。
With the record of high-resolution of the Chinese loess section at Yuanbao in Linxia, boundary age constituted three age models based on the climatic events, namely the boundary age of MIS1/2 at 2.3m is 11.5kaBP and the boundary age of MIS3/4 at 21.4m is 59.8kaBP. The boundary ages were determined in accordance with the latest research results, i.e. the dating of stalagmite in the Nanjing Hulu Cave. Model 1（0kaBP-59.8kaBP）, model 2 （0kaBP - 11.5kaBPand 11.5kaBP - 59.8kaBP） and model 3 （11.5kaBP-59.8kaBP） were used as the nodal-controlled age. With three models being the nodal-controlled ages, the susceptibility age model and grain-size age model were used to calculate the deposition times of the various horizons of the studied section respectively. A comparative analysis was made on the deposition time of the same horizon calculated by different models with the calculated ages. As viewed from the lithologic characters and the climatic stages, the susceptibility and grain-size age models have some shortcomings, but the stratigraphic deposition time calculated by the susceptibility and grain-size models with model 2 as the nodal-controlled age at the glacial period and the interglacial period is more consistent with the real deposition times of the strata. If some more suitable nodal-controlled ages were interpolated into the major climatic stages to determine the stratigraphic deposition time, the age calculated by the model would be more approximated to the actual stratigraphic deposition age. The usage of susceptibility and grain-size age models at Quaternary period was not suitable.
出处
《地理研究》
CSCD
北大核心
2006年第3期415-420,共6页
Geographical Research
基金
科学技术部重大国际合作项目(2002CB714004)
国家杰出青年基金项目(NSFC40125001)
