| 美国Zion国家公园红层地貌发育研究 |
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| 关键词:Zion National Park red beds Danxia landforms developmental mechanism |
| 基金项目:国家自然科学基金项目(编号: 41171013); 国家留学基金委公派留学联合培养博士生项目(编号: 201306380019) |
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| A Study of the Development of Red Bed Landforms in Zion National Park, the United States |
| As the research on red beds and Danxia landforms in China is becoming increasingly known by geoscientists outside China, it is quite necessary for Chinese researchers to know and understand red beds and their geomorphic development in other countries. As a representative of red beds distributed in the western United States, Zion National Park is characterized by a geomorphic combination of plateau and canyons in arid climate. Based on field investigation and analysis of rock samples, this paper looks at the developmental mechanism of landforms in Zion National Park from the aspects of geological setting, lithological features, and exogenic forces. In terms of general geologic structure, Zion is a fault block formed on the western margin of the Colorado Plateau. There are few folds and faults, but joints are exceptionally well developed in Zion, they are responsible for the orientation of canyon network. The dominant rock strata exposed in Zion belong to red beds, which were mainly deposited in the Jurassic with a wide range of environments, including near shore/shallow sea, streams, lakes, and deserts. In terms of lithological features, most red beds in Zion are fine-grained sandstones and siltstones. Among them, the spectacular cliffs in Zion are made of eolian quartz sandstones. However, due to cement differences of each rock member, there are remarkable diversities in rock strength and colors. Moreover, this study also found that rock hardness values do not positively correlate with mountain slopes in Zion. The uniformity of a certain rock layer can also affect mountain slopes. Therefore, being composed of uniform sandstones, the aeolian rock formations and Springdale Member can form steep cliffs, while other rock layers, which contain soft interlayers, can only form gentle slopes. Finally, in terms of exogenic forces, fluvial incision plays a dominant role in the formation of cliffs and canyons in Zion, followed by lateral erosion and sapping process. |
| PAN Zhi-xin,PENG Hua,REN Fang,John ENCARNACION.2016.A Study of the Development of Red Bed Landforms in Zion National Park, the United States[J].Acta Geoscientica Sinica,37(1):116-126. |
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