Sources and conservative mixing of uranium in the Taiwan Strait
-
摘要: 本研究通过MC-ICP-MS对在台湾海峡南部采集的2013年春季海水样品进行了U含量及同位素组成的测定分析,探究了U在台湾海峡的地球化学行为。U的各个同位素的平均浓度如下:238U为3.23±0.14 μg/kg,235U为(2.34±0.09)×10-2 μg/kg,234U为(2.05±0.07)×10-4 μg/kg。而U同位素比值分别是:δ234U为155±18,238U:235U为138±2。台湾海峡的U含量和同位素比值与开阔大洋基本一致,由此可见,该海峡的U主要由开阔大洋所贡献。将本研究结果与研究海域附近海区的相关结果一同比较,包括九龙江和珠江河口区,厦门湾及南海南部,可以看到台湾海峡U浓度与盐度具有显著的正相关关系(U:S;U=(0.0934±0.0024)×S+(0.0920±0.0615)),表明U在台湾海峡呈现保守性混合。为更好地了解U在台湾海峡的地球化学行为,本文运用了多端元混合模型来比较各个潜在来源的贡献大小。开阔大洋对本研究中U的贡献比例为69-95%,河流为~2%,而大气沉降仅约为0.13%。因此,该模型结果与U浓度和同位素比值分析所得出的结论是一致的,即台湾海峡的U主要由开阔大洋所贡献,并具有保守性的地球化学行为。另外,沉积物间隙水有可能是台湾海峡U的一个重要来源,其可能的贡献比例为3-29%,这与前人基于镭同位素得到的观测结果一致。但后续还需要对台湾海峡沉积物间隙水及其向上覆水体的扩散进行更深入的调查研究。Abstract: Seawater samples are collected in the spring of 2013 from the Taiwan Strait for the analysis of uranium (U) concentrations and isotopic compositions using MC-ICP-MS, and the geochemical behavior patterns of U in the Taiwan Strait are then investigated. Average concentrations of individual U isotopes are (3.23±0.14) μg/kg for 238U, (2.34±0.09)×10-2 μg/kg for 235U and (2.05±0.07)×10-4 μg/kg for 234U. Correspondingly, the U isotopic compositions are 155±18 for δ234U and 138±2 for 238U:235U. The U concentrations and isotopic ratios in the Taiwan Strait are similar to those of open ocean seawater, suggesting the dominance of the open ocean input to the strait's U pool. However, river input, as suggested by the slightly lower salinity than that of the open ocean, also affected the U concentrations and isotopic compositions in the strait. From a compilation of U concentrations in the Taiwan Strait and adjacent areas, including the Jiulong Estuary and Zhujiang Estuary, the Xiamen Bay and the northern South China Sea, a strong and significant relationship between U concentration and salinity[U:S; U=(0.093 4±0.002 4)S+(0.092 0±0.061 5)] is revealed, suggesting conservative mixing of U in the Taiwan Strait. To better understand the U geochemistry in the Taiwan Strait, a multiple endmembers mixing model is applied to estimate the contributions of potential sources. The open ocean seawater contributed 69%-95% of U in the Taiwan Strait, with river water approximately 2%, and dust deposition only around 0.13%. Therefore, the model results supported the open ocean input source and the conservative mixing behavior of U derived from the observation of U concentrations and isotopic ratios and U:S ratios. The sediment interstitial water may be an important source of U to the Taiwan Strait with a possible contribution of 3%-29%, consistent with previous investigations based on radium isotopes. However, further investigations are warranted to examine the U concentration in the sediment interstitial water and its input to the overlying seawater in the Taiwan Strait.
-
Key words:
- conservative mixing /
- uranium /
- seawater /
- Taiwan Strait
-
Anderson M B, Stirling C H, Zimmermann B, et al. 2010. Precise determination of the open ocean 234U/238U composition. Geochemistry, Geophysics, Geosystems, 11(12):Q12003 Auro M E, Robinson L F, Burke A, et al. 2012. Improvements to 232-thorium, 230-thorium, and 231-protactinium analysis in seawater arising from GEOTRACES intercalibration. Limnology and Oceanography:Methods, 10(7):464-474 Barnes C E, Cochran J K. 1990. Uranium removal in oceanic sediments and the oceanic U balance. Earth and Planetary Science Letters, 97(1-2):94-101 Cai Weijun, Dai Minhan, Wang Yongchen, et al. 2004. The biogeochemistry of inorganic carbon and nutrients in the Pearl River estuary and the adjacent northern South China Sea. Continental Shelf Research, 24(12):1301-1319 Cai Pinghe, Huang Yipu, Qiu Yusheng. 1996. The geochemistry of 238U and 234Th in the Jiulong River Estuary. Acta Oceanologica Sinica (in Chinese), 18(5):52-60 Carroll J, Moore W S. 1993. Uranium removal during low discharge in the Ganges-Brahmaputra mixing zone. Geochimica et Cosmochimica Acta, 57(21-22):4987-4995 Chen J H, Edwards R L, Wasserburg G J. 1986a. 238U, 234U and 232Th in seawater. Earth and Planetary Science Letters, 80(3-4):241-251 Chen Min, Huang Yipu, Chen Feizhou, et al. 1997. Study of dissolved uranium isotopes in some sea areas of China. Journal of Oceanography in Taiwan Strait (in Chinese), 16(3):285-292 Chen J H, Wasserburg G J, Damm K L V, et al. 1986b. The U-Th-Pb systematics in hot springs on the East Pacific Rise at 21°N and Guaymas Basin. Geochimica et Cosmochimica Acta, 50(11):2467-2479 Cochran J K. 1992. The oceanic chemistry of the uranium-and thorium-series nuclides. In:Ivanovich M, Harman R S, eds. Uranium-series Disequilibrium:Applications to Earth, Marine, and Environmental Sciences. Oxford:Oxford University Press, 334-395 Cochran J K, Carey A E, Sholkovitz E R, et al. 1986. The geochemistry of uranium and thorium in coastal marine sediments and sediment pore waters. Geochimica et Cosmochimica Acta, 50(5):663-680 Cochran J K, Hirschberg D J, Livingston H D, et al. 1995. Natural and anthropogenic radionuclide distributions in the Nansen Basin, Artic Ocean:scavenging rates and circulation timescales. Deep Sea Research Part II:Topical Studies in Oceanography, 42(6):1495-1517 Dai Minhan, Meng Feifei, Tang Tiantian, et al. 2009. Excess total organic carbon in the intermediate water of the South China Sea and its export to the North Pacific. Geochemistry, Geophysics, Geosystems, 10(12):Q12002 Delanghe D, Bard E, Hamelin B. 2002. New TIMS constraints on the uranium-238 and uranium-234 in seawaters from the main ocean basins and the Mediterranean Sea. Marine Chemistry, 80(1):79-93 Dunk R M, Mills R A, Jenkins W J. 2002. A reevaluation of the oceanic uranium budget for the Holocene. Chemical Geology, 190(1-4):45-67 Gariépy C, Ghaleb B, Hillaire-Marcel C, et al. 1994. Early diagenetic processes in Labrador Sea sediments:uranium-isotope geochemistry. Canadian Journal of Earth Sciences, 31(1):28-37 Guo Song, Hu Min, Zamora M L, et al. 2014. Elucidating severe urban haze formation in China. Proceedings of the National Academy of Sciences of the United States of America, 111(49):17373-17378 Henderson G M, Anderson R F. 2003. The U-series toolbox for paleoceanography. Reviews in Mineralogy and Geochemistry, 52(1):493-531 Henderson G M, Slowey N C, Haddad G A. 1999. Fluid flow through carbonate platforms:constraints from 234U/238U and Cl- in Bahamas pore-waters. Earth and Planetary Science Letters, 169(1-2):99-111 Hiess J, Condon D J, McLean N, et al. 2012. 238U/235U systematics in terrestrial uranium-bearing minerals. Science, 335(6076):1610-1614 Hong Huasheng, Chai Fei, Zhang Caiyun, et al. 2011. An overview of physical and biogeochemical processes and ecosystem dynamics in the Taiwan Strait. Continental Shelf Research, 31(6S):S3-S12 Hu Jianyu, Hong Huasheng, Li Yan, et al. 2011. Variable temperature, salinity and water mass structures in the southwestern Taiwan Strait in summer. Continental Shelf Research, 31(6S):S13-S23 Hu Jianyu, Kawamura H, Hong Huasheng, et al. 2001. Hydrographic and satellite observations of summer time upwelling in the Taiwan Strait:a preliminary description. Terrestrial, Atmospheric and Oceanic Sciences, 12(2):415-430 Hu Jianyu, Kawamura H, Li Chunyan, et al. 2010. Review on current and seawater volume transport through the Taiwan Strait. Journal of Oceanography, 66(5):591-610 Jan S, Tseng Y H, Dietrich D E. 2010. Sources of water in the Taiwan Strait. Journal of Oceanography, 66(2):211-221 Jiang Xueyan. 2008. Study of the distribution and genesis of uranium in the main channel and estuary of Yellow river and the southern coast of Laizhou Bay (in Chinese)[dissertation]. Qingdao:Ocean University of China Jiang Xueyan, Yu Zhigang, Ku T L, et al. 2007. Behavior of uranium in the Yellow River Plume (Yellow River Estuary). Estuaries and Coasts, 30(6):919-926 Ku T L, Knauss K G, Mathieu G G. 1977. Uranium in open ocean:concentration and isotopic composition. Deep-Sea Research, 24(11):1005-1017 Liu Yanna. 2014. Long-lived U and Th measurement of MC-ICP-MS in seawater and geochemical behaviors of Th from the Taiwan Strait (in Chinese)[dissertation]. Xiamen:Xiamen University Liu Qian, Dai Minhan, Chen Weifang, et al. 2012. How significant is submarine groundwater discharge and its associated dissolved inorganic carbon in a river-dominated shelf system? Biogeosciences, 9(5):1777-1795 Liu Shao, Qin Peiling, Zhang Huiling. 1988a. Distribution characteristics of uranium and thorium in the water samples of the Yangtze River. Bulletin of Mineralogy, Petrology and Geochemistry (in Chinese), 7(1):12-12 Liu Shao, Sun Huili, Wu Liangji, et al. 1988b. Concentration and isotopic composition of uranium and thorium in water and suspension of the Pearl River. Tropic Oceanology (in Chinese), 7(3):99-102 Lü E, Zheng Lei, Chen Min, et al. 2008. Size-fractionated uranium isotopes in surface waters in the Jiulong Estuary in China. Acta Oceanologica Sinica, 27(1):29-41 Moran S B, Shen C C, Edwards R L, et al. 2005. 231Pa and 230Th in surface sediments of the Arctic Ocean:Implications for 231Pa/230Th fractionation, boundary scavenging, and advective export. Earth and Planetary Science Letters, 234(1-2):235-248 Morford J L, Emerson S. 1999. The geochemistry of redox sensitive trace metals in sediments. Geochimica et Cosmochimica Acta, 63(11-12):1735-1750 Naik H, Chen C T A. 2008. Biogeochemical cycling in the Taiwan Strait. Estuarine, Coastal and Shelf Science, 78(4):603-612 Not C, Brown K, Ghaleb B, et al. 2012. Conservative behavior of uranium vs. salinity in Arctic sea ice and brine. Marine Chemistry, 130-131:33-39 Okubo A, Obata H, Gamo T, et al. 2012. 230Th and 232Th distributions in mid-latitudes of the North Pacific Ocean:effect of bottom scavenging. Earth and Planetary Science Letters, 339-340:139-150 Owens S A, Buesseler K O, Sims K W W. 2011. Re-evaluating the 238U-salinity relationship in seawater:implications for the 238U-234Th disequilibrium method. Marine Chemistry, 127(1-4):31-39 Palmer M R, Edmond J M. 1993. Uranium in river water. Geochimica et Cosmochimica Acta, 57(20):4947-4955 Pates J M, Muir G K P. 2007. U-salinity relationships in the Mediterranean:implications for 234Th:238U particle flux studies. Marine Chemistry, 106(3-4):530-545 Pelt E, Chabaux F, Innocent C, et al. 2007. Rates of weathering rind formation from 238U-234U-230Th chronometry:application to basalt weathering. Cologne:Goldschmidt Pelt E, Chabaux F, Stille P, et al. 2013. Atmospheric dust contribution to the budget of U-series nuclides in soils from the Mount Cameroon volcano. Chemical Geology, 341:147-157 Pett-Ridge J C, Monastra V M, Derry L A, et al. 2007. Importance of atmospheric inputs and Fe-oxides in controlling soil uranium budgets and behavior along a Hawaiian chronosequence. Chemical Geology, 244(3-4):691-707 Robinson L F, Belshaw N S, Henderson G M. 2004. U and Th concentrations and isotope ratios in modern carbonates and waters from the Bahamas. Geochimica et Cosmochimica Acta, 68(8):1777-1789 Scholten J C, Fietzke J, Mangini A, et al. 2008. Advection and scavenging:effects on 230Th and 231Pa distribution off Southwest Africa. Earth and Planetary Science Letters, 271(1-4):159-169 Shen Chuanchou, Li K S, Sieh K, et al. 2008. Variation of initial 230Th/232Th and limits of high precision U-Th dating of shallow-water corals. Geochimica et Cosmochimica Acta, 72(17):4201-4223 Staudigel H, Plank T, White B, et al. 1996. Geochemical fluxes during seafloor alteration of the basaltic upper oceanic Crust:DSDP sites 417 and 418. Geophysical Monograph, 96:19-38. Staudigel H, Plank T, White B, et al. 1996. Geochemical fluxes during seafloor alteration of the basaltic upper oceanic crust:DSDP Sites 417 and 418. In:Bebout G E, Scholl D W, Kirby S H, et al., eds. Subduction Top to Bottom. Geophysical Monograph Series, vol. 96. Washington:American Geophysical Union, 19-38 Sun Huili, Liu Shao, Zhang Huilin, et al. 1987. A preliminary study on uranium distribution and its isotopic composition in Zhujiang estuarine water. Tropical Oceanography (in Chinese), 6(4):55-60 Swarzenski P W, Baskaran M. 2007. Uranium distribution in the coastal waters and pore waters of Tampa Bay, Florida. Marine Chemistry, 104(1-2):43-57 Swarzenski P W, Campbell P, Porcelli D, et al. 2004. The estuarine chemistry and isotope systematics of 234, 238U in the Amazon and Fly Rivers. Continental Shelf Research, 24(19):2357-2372 Tan Saichun, Yao Xiaohong, Gao Huiwang, et al. 2013. Variability in the correlation between Asian dust storms and chlorophyll a concentration from the north to equatorial Pacific. PLoS One, 8(2):e57656 Taylor S R, McLennan S M, Armstrong R L, et al. 1981. The composition and evolution of the continental crust:rare earth element evidence from sedimentary rocks. Philosophical Transactions of the Royal Society:A. Mathematical, Physical and Engineering Sciences, 301(1461):381-399 Thomas A L, Henderson G M, Robinson L F. 2006. Interpretation of the 231Pa/230Th paleocirculation proxy:new water-column measurements from the southwest Indian Ocean. Earth and Planetary Science Letters, 241(3-4):493-504 Wang Ruomei, You Chenfeng. 2013. U and strontium isotopic evidence for strong submarine groundwater discharge in an estuary of a mountainous island:a case study in the Gaoping River Estuary, Southwestern Taiwan. Marine Chemistry, 157:106-116 Wong G T F, Ku T L, Mulholland M, et al. 2007. The Southeast Asian time-series study (SEATS) and the biogeochemistry of the South China Sea-An overview. Deep Sea Research:Part II. Topical Studies in Oceanography, 54(14-15):1434-1447 Xiao Hui, Guo Xiaogang, Wu Risheng. 2002. Summarization of studies on hydrographic characteristics in Taiwan Strait. Journal of Oceanography in Taiwan Strait (in Chinese), 21(1):126-138 Zheng Jian, Yamada M. 2006. Determination of U isotope ratios in sediments using ICP-QMS after sample cleanup with anion-exchange and extraction chromatography. Talanta, 68(3):932-939 Zheng J, Yamada M, Aono T, et al. 2006. Vertical distribution of uranium concentrations and 235U/238U atom ratios in the coastal water off Aomori, Japan:a survey prior to the operation of a nuclear fuel reprocessing facility. Journal of Radioanalytical and Nuclear Chemistry, 270(3):669-675 Zhou Zhonghuai, Xu Lijun, Liu Xingjun. 1989. The chemical behavior of uranium in the Huanghe estuary. Marine Sciences (in Chinese), (2):38-42
点击查看大图
计量
- 文章访问数: 1124
- HTML全文浏览量: 63
- PDF下载量: 793
- 被引次数: 0