地质学报2017，Vol.91Issue(3)：678-689,12.
西安地区S4古土壤剖面中古水分指标与水环境研究
The Study on the Paleowater Content Indexes and Water Environment in the Profile of S4 Paleosol in Xi'an Area
摘要
Abstract
Based on the field investigation and experimental analysis,it was found that iron-manganese concretions,goethite [α-FeO (OH)],which could indicate the soil moisture content,groundwater enrichment and water cycle in the profile of S4 paleosol in An village of Lantian in Xi'an.It was also determined the weathered and leached loess layer and CaCO3 illuvial layer that significantly migrated out of the argillic layer in Xi'an area.Goethite was distributed on the earth surface as yellow-brown filas and its content can be up to 3.3 ％.Iron-manganese concretions was brown-black spherical and crystal granular in the electron microscopy,and the content of iron and manganese was very high.The goethite and ironmanganese concretion layer was about 0.6 m,and formed in the position of the underground water level.According to the research,we could propose that the iron-manganese concretions,the weathered and leached loess layer and CaCO3 illuvial layer can be used as an important index of restoring paleo-moisture content.Goethite,iron-manganese concretions,the formation of weathered and leached loess layer,the migration depth of CaCO3 concretions and red ferrunious films shows that the climate in Xi'an is subtropical,of which the mean annual temperature was 15 ～ 16℃ and the mean annual rainfall was between 900～1000mm during the development period of S4 paleosol.At that time Qinling Mountains lost the function of the boundary between subtropics and temperate zone.In the development period of S4 paleosol,the depth of gravity water in soil in Xi'an area was 3.3 m,then after the soil water evaporation and transpiration consumption,the rest of the soil water content in 3.3 m depth was about 25％,and it closed to the saturated moisture content (50％) in goethite and iron-manganese concretions development layer.Soil moisture was very sufficient,and normal water cycle and positive water balance occurred,there were more water to recharge the groundwater of groundwater,as it was suitable for the development of lush forest vegetation at that time.The study in this paper has broaden the Quaternary new content and indexes proposed by us can be as standards and methods in studying soil water content,soil water form and water cycle at home and abroad.关键词
S4古土壤/铁锰结核与针铁矿/古水循环/含水量指标/水分平衡/西安地区Key words
the S4 paleosol/iron-manganese concretions and goethite/paleowater cycle/water balance/water content index/water balance/Xi'an area引用本文复制引用
赵景波,马延东,罗小庆,邵天杰,刘瑞..西安地区S4古土壤剖面中古水分指标与水环境研究[J].地质学报,2017,91(3):678-689,12.基金项目
本文为陕西省自然科学基础研究计划项目(2015JM4153)、中国地质调查局西安地质调查中心项目(水[2016]4、中国科学院黄土与第四纪地质国家重点实验室项目(SKLLQG1626)资助的成果. （2015JM4153）
