古土壤干湿特征指示晚古生代气候演化

古土壤是地质历史时期气候变化的重要记录者，通过古土壤记录的信息，可以定性和定量重建深时古环境和古气候，为认识地质历史时期的各种地质事件提供依据。前人大多对特定区域展开古土壤研究，对全球性古土壤数据的整理和古气候、古环境研究相对较少。基于古土壤的干湿情况对古气候环境的指示作用，我们按照植物根迹、根系结构与根化石、黏土矿物以及古土壤的结构构造等依据，将前人报道的古生代(410～255 Ma)古土壤分为干旱古土壤和湿润古土壤两种类型。将古土壤干湿特征与其他气候敏感性沉积物进行对照，显示为干旱古土壤分布与钙质结核以及蒸发岩等指示干旱气候带的敏感性沉积物分布一致，湿润古土壤分布与高岭石、煤以及铝土矿等指示湿润气候带的敏感性沉积物分布一致。干旱古土壤大都分布在晚古生代中低纬度干旱地区；湿润古土壤大都分布在晚古生代赤道附近及中纬度湿润地区。通过以上分析认为，古土壤干湿特征可以作为一个新的气候敏感指标指示古气候环境，进而作为划分气候带的有力依据。

The dry and wet characteristics of paleosoil indicating the climatic evolution of Late Paleozoic

Paleosoil is an important record of climate change in geological history. Through the information of palaeosoil records, the paleoenvironmentand paleoclimatecan be reconstructed qualitatively and quantitatively, providing basis for understanding various geological events in geological history. Most of the previous studies have been carried out on palaeosoil in specific areas, but the global palaeosoil data collation, paleoclimateand paleoenvironment research are relatively few. Methods: Based on the indicator function of the dry and wet condition of paleosoil to the paleoclimate environment, we classified the paleosol (410~255 Ma) reported by previous researchers into two types: arid paleosoil and humid paleosoil according to the plant root trace, root structure and root fossil, clay minerals and the structure of paleosoil. Results: Paleoclimate compares the dry and wet characteristics of paleosoils with other climate-sensitive sediments, Compared with typical sensitivity sediments, the arid and humid paleosoil distributions are consitent with calcareous tuberculosis (evaporite), kaolinite (coal and bauxite), respectively. The arid paleosoilis mainly distributed in the middle and low latitude arid area of late Paleozoic. Humidpaleosoils are mainly distributed in the Late Paleozoic near the equator and mid-latitude moist regions. Conclusions: Based on the above analysis, it is concluded that the dry and wet characteristics of paleosoil can be used as a new climate sensitive index to indicate the paleoclimate environment, and then as a strong basis for the division of climatic zones.