景泰老龙湾砂砾岩峰林地貌形成与演化

FOMATION AND EVOLUTION OF GLUTENITE PEAK FOREST LANDFORM IN LAOLONGWAN OF JINGTAI COUNTY,CHINA

景泰老龙湾砂砾岩峰林是世界罕见的地貌景观,时至今日,对老龙湾砂砾岩地貌的形成演化特征研究尚显薄弱。本文在前人研究的基础上,通过多次现场考察和研究,探讨了老龙湾砂砾岩峰林地貌的形成演化过程。认为老龙湾砂砾岩峰林地貌是青藏高原东北缘边界地带对青藏高原隆升、黄河演化和气候变化响应的直接产物,老龙湾盆地沉积的上新世—早更新世砂砾构成了物质基础,海原断裂带是砂砾岩峰林形成的构造基础,黄河水系切割及风蚀作用是其外动力塑造条件。地貌、地层学证据表明,晚新生代以来老龙湾砂砾岩的形成演化可划分为物质基础形成阶段、流水地貌形成阶段、峰林地貌塑造成型三个阶段。老龙湾砂砾岩峰林发育演化过程的构建,为黄河石林国家地质公园的建设提供了新的理论依据。

Jingtai Laolongwan glutenite peak forest is a rare geomorphic landscape in the world. Up to now,the research on the formation and evolution characteristics of Laolongwan glutenite landform in Jingtai is still weak. On the basis of many field investigations and previous studies, this paper discusses the formation and evolution process of glutenite peak forest landform in Laolongwan. The study shows that the landform of glutenite peak forest in Laolongwan is the direct product of the response of the northeast edge of the Tibetan Plateau to the uplift of the Tibetan Plateau, the evolution of the Yellow River and climate change. The Pliocene early Pleistocene sand gravel deposited in Longwan basin constitutes the material basis, the existence of Haiyuan fault zone is the structural basis for the formation of glutenite peak forest, and the cutting and wind erosion of the Yellow River system are the external dynamic shaping conditions. Geomorphic and stratigraphic evidence shows that the formation and evolution of Laolongwan sandy conglomerate since the late Cenozoic can be divided into three stages: the formation stage of material foundation, the formation stage of flowing water landform and the shaping stage of peak forest landform. The construction of the development and evolution process of glutenite peak forest in Laolongwan provides a further theoretical basis for the construction of the Yellow River Shilin National Geopark.