碩士 / 國立臺灣師範大學 / 地球科學系 / 101 / Marine terraces include raised wave-cut platforms and sea cliffs. Therefore, they indicate regional tectonics, paleo-climate and former sea-level changes. They may not be only influenced by eustatic changes, but also by regional tectonic movements. The Taiwan Island is located on the collisional boundary between the Philippine Sea plate and Eurasian plate. The mountain belt in northeastern Taiwan is undergoing extension and the mountain belt is collapsing. But there are many well developed marine terraces that seem to be contradictory with the northern Taiwan tectonics.
In this study, we utilized aerial photographic interpretation, geomorphic analysis of 40m-DTM, high-resolution topographic profiles obtained from RTK-GPS easurements and data analysis to characterize the coastal geomorphic features, mincluding the elevation of terrace, thickness of sediments, bedrock outcrops and topographic profiles.
Along the coast of northeastern Taiwan, there are two steps of marine terraces. The higher terraces belong to Pleistocene terraces, and their distribution is very scattered and difficult to analyze, thus we will not discuss them in this study. The other step are lower terraces, and their elevations are averaged from 5-10m after measurement of RTK-GPS. They are well developed along the coastal lowland and with better continuity in this area. Based on radiocarbon dating, these lower terraces belong to middle Holocene terraces, and the average uplift rate is about 0.62-0.75mm/yr from about 4-5ka.
The result shows that this area has very low uplift rate. The slow uplift pattern is generally consistent with isostatic hypothesis, in which topography on the earth surface is compensated at depth. The crust of northern Taiwan may be gradually rising and forms continuous marine terraces along the coast today, after a large amount of materials are eroded away after a longer history of mountain building.
| Identifer | oai:union.ndltd.org:TW/101NTNU5135018 |
| Date | January 2013 |
| Creators | Jia-Ying Tsai, 蔡佳穎 |
| Contributors | J. Bruce H. Shyu, En-Chao Yeh, 徐澔德, 葉恩肇 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 215 |
Page generated in 0.0169 seconds