摘要
根据显微结构和矿物成分等的鉴定,笔者在陕西旬阳溶蚀残余红土中,发现了在北亚热带及其以北地区不存在的原生石英的强烈溶蚀结构和次生石英、玉髓微晶粒结构,这一发现对确定该区古环境变迁提供了有力证据。结合孢粉和化学成分资料,本文得出以枯土矿物占优势的旬阳溶蚀残余红土形成于高温多雨的中亚热带气候条件下,植被以常绿阔叶林为主,土壤类型相当于现代的红壤,时代属于中新世。
On the basis of the identification of the microstructures and mineral composition, the authors discovered strongly corrosive microstructure of primary quartz and the microgranular textures of secondary quartz and chalcedonite which do not exist in the north subtropics and areas farther to the north,and this discovery provides strong evidence for the determination of the change of the paleoenvironment. In the light of a synthetical analysis of the microstructure, sporo-pollen and chemical composition, it has been determined that the corrosive relic red earth, which consists dominantly of clay minerals was formed in the middle subtropics with a pluvial and hot climate and that the dominant vegetation was evergreen broadleaved forest. The soil type of the red earth corresponds to the recent red earth in the middle subtropis and its age is Miocene.
出处
《地质论评》
CAS
CSCD
北大核心
1999年第1期66-70,T001,共6页
Geological Review
基金
地质矿产部"九五"重点科技项目(编号9501104)
地质矿产部岩溶动力学开放研究实验室
国家自然科学基金重点项目(编号49632100)
关键词
红土
硅质矿物
微结构
陕西
旬阳地区
red earth
siliceous mineral
microstructure
Xunyang,Shaanxi
