汉中盆地全新世沉积物成因研究

对于汉中盆地全新世沉积物野外考察和实验分析表明 ,汉江第一、二、三级阶地的松散沉积物具有风成黄土的特点。将其粒度成分和各项参数与黄土高原全新世典型黄土的对比分析 ,证明了汉中盆地在全新世时期有风成黄土堆积和古土壤形成。

STUDY ON THE HOLOCENE LOESS SEDIMENTARY STRATIGRAPHY IN HANZHONG BASIN

Located in the Qinling Bashan Mountains, the Hanzhong Basin is in an environment of euergreen broadleaf forest of North Asia. It is commonly considered that there is no Quaternary aeolian loess accumulation in the basin because of the barrier of the Taibai Mountain on its northern side. Based on the field investigation and laboratory analysis in this paper, the Holocene sedimentary stratigraphy in the basin is studied. By comparing the results with those of the typical Holocene loess on the Loess plateau, it is revealed that there is the Holocene eolian loess accumlation in Hanzhong Basin, and the Taibai Mountain actually was not the barrier for dust transport by northwest monsoon during the Holocene epoch, in other words, dust could be transported by northwest monsoon over the Qinling Mountains during the Holocene Epoch. Comparing with the Holocene loess in Luochuan, the soil forming process in Hanzhong Basin was more violent, so the content of coarse sand in the loess and the palaeosoil is low, and the content of clay is high. However, the property of the loess in Hanzhong Basin is close to that in Guanzhong Basin.