丁村旧石器遗址群的黄土地层研究

STUDY ON THE LOESS-PALEOSOL SEQUENCE OF THE DINGCUN PALEOLITHIC SITES

通过测量黄土的磁化率 ,并结合传统的黄土地层学研究方法 ,对丁村旧石器文化遗址群中两个典型的剖面 ,即代表丁村旧石器中期文化的 10 0地点和代表丁村旧石器早期文化的 79:0 2地点文化层上部的黄土 -古土壤序列进行划分 ,并将其结果与位于丁村附近黄土塬上的敬村黄土剖面和典型洛川黄土剖面的地层和磁化率曲线进行对比。结果表明 ,丁村 10 0地点地层上部黄土 -古土壤序列为S0 ,L1,S1;而 79:0 2地点上部的黄土 -古土壤序列则包括S0 ,L1,S1,L2 ,S2 。因此 ,丁村 10 0地点文化层的年代大于S1的形成年代即 0 13MaB .P .,79:0 2地点文化层的年代大于S2 的轨道调谐年龄 ,即 0 2 4 7MaB .P .。

Since the discovery of Dingcun Palaeolithic Sites in 1953, much has been done in the studies of the strata and mammalian fossils at the site. However, the age of the Dingcun Palaeolithic Sites is still a controversial issue. One main reason is that there is still much controversy concerning the lithostratigraphy of the loess paleosol sequence overlying the fluvial deposits. For the Paleolithic Site 100,some researchers regard the 'red soil' overlying the fluvial deposits as late middle Pleistocene in age,while the others regard it as the same as the Malan loess. As for the Paleolithic Site 79:02,most researchers attribute it to the late 'red soil' period,but this term is too coarse to reflect the real age of this cultural horizon. In the past decades great progresses have been made in the research of loess in China, one of which was the dating of every layer of the loess seqence. The loess paleosol sequence, therefore, can be used not only as an excellent means for reconstructing the history of palaeomonsoon in east Asian but also as a dating tool. This dating method has been proved to be useful for loess terraces,providing that the loess paleosol sequence is stipulated correctly. In this paper,the strata at Site 100 representative of the Dingcun Middle Paleolithic Culture and Site 79:02 representative of the Dingcun Early Paleolithic Culture are restudied,the stratigraphic section is analyzed, and the magnetic susceptibility of the loess paleosol is measured. To verify the authenticity of the division of loess strata that we have made, a similar division and magnetic susceptibility measurement have been made at Jingcun profile located at Loess Yuan, where loess strata are well developed. The obtained results are then compared with the typical Luochuan loess paleosol sequence and the loess paleosol squences of 2 paleolithic sites at Dingcun. According to our study,the loess paleosol sequence at Dingcun site 100 consists of S 0,L 1 and S 1. Since the horizon containing the Paleolithic Culture and the fossil of Dingcun man is about 4 5～ 9m below S 1,the age of which is determined to be 0.13Ma B.P. by synthetic dating method,then an age of older than 0.13Ma B.P. is suggested for the Middle Paleolithic culture at Dingcun sites. The loess paleosol sequence of Dingcun 79:02 profile involves S 0,L 1,S 1,L 2 and S 2. According to the Orbit Tuning Age Mode which gives S 2 an age of 0.247Ma B.P.,the age of Paleolithic Culture at Site 79:02 should be older than 0.247Ma B.P.