Preliminary Geochemical and Isotopes study of the Erren river water
| Autor: | Siu-Leung Chung, 鍾小良 |
|---|---|
| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 Taiwan has the highest physical denudation rate in the world. Chemical and isotopic compositions of river water are sensitive tracers for chemical erosion. During the last two years, we have sampled more than 100 river waters at 19 stations along the Er-ren River. Various major (i.e., Na+, K+, Mg2+, Ca2+, Cl-, HCO3- and SO42- ) and trace constituents, as well as Sr and U isotopes, were determined. Applying factor analysis method, we found that the most important factors controlling the river chemical compositions are (1) seasalt contribution and/or tidal effect; (2) ambient rock; and (3) anthropogenic pollutant. Other effects including regional and seasonal variability are also detected. The 87Sr/86Sr and 1/Sr plot indicates of mixing among four Sr sources. Four near estuary stations display strong seawater 87Sr/86Sr signature (0.7090∼0.7095). In mid stream stations, much higher 87Sr/86Sr（0.7105∼0.7125）are observed possibly due to chemical weathering of ambient rocks. The isotopic compositions in upstream river waters range 0.7095 to 0.7105. Interestingly, the three different tributary samples show distinctive Sr concentration and isotopic compositions. Uranium isotopic compositions vary largely in the Er-ren River. The highest 234U/238U （2.48，2.32） was found at the Chong-yi station and ground water, possibly were affected by deep situated groundwater. All mid and upstream waters show small 234U/238U variations (1.50∼1.87) in strong contrast to that of tributary waters (1.2 to 2.5).The activities of four estuary samples (1.22∼1.25) are similar to that of seawater (1.14). |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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