碩士 / 國立中山大學 / 海洋地質及化學研究所 / 96 / Abstract
The purposes of this study are to understand the variations of the particulate and dissolved 210Pb and 210Po profiles in the water column of Gaoping Submarine Canyon(GSC) and to compare the distributions of the two nuclides in settling particles and sediments. Different types of samples taken in this area were analyzed for 210Pb and 210Po in order to understand processes involved in the particulate transport. Seawater samples were collected from Ocean Researcher III Cruise (ORIII-1192 in Nov, 2006). Sediment trap was deployed on Jun 21, 2000 and recovered on Jul 20, 2000 (ORIII-634). Sediments cores collected from ORIII-642 on Jul 21, 2000 (Core A-B) and ORIII-696 on Apr 7, 2001 (Core D-F) using multicorer.
The profiles of 210Pb and 210Po in water column could be divided into two types one is estuarine and the other is oceanic. The profiles of dissolved nuclides in estuarine stations (CW1 to 3) are lower than in the oceanic stations (CW4-5). Because stations CW1 to 3 are controlled by large amount of terrigenous particles, scavenging in the three stations is quite obvious.
The nuclide activities of the settling particles decrease with depth, probably due to dilution by resuspended surface sediment of lower activities, similar to observations in this study area. The downcore distributions of 210Pb and 210Po show clearly disequilibria between the two nuclides and suggested that sediment deposited in GSC has been disturbed down to 40-50 cm deep. All the data indicate the 210Po in the water column and in the settling particles as well as in the surface sediments is strongly deficient relative to its parent, 210Pb. Using a box-model and considering the influence of horizontal transports, we may calculate the residence times of 210Po in the 100m water layer in the GSC, to be 2.1d for the dissolved phase and 7.0 d for the particulate phase with a total 210Pb residence time is 3.8d.
| Identifer | oai:union.ndltd.org:TW/096NSYS5271008 |
| Date | January 2008 |
| Creators | Ya-ting Shen, 沈雅婷 |
| Contributors | Hui-Ling Lin, Yu-Chia Chung, 林慧玲, 鍾玉嘉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 106 |
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