Magnetic Properties of Recent Sediments at Tianxing Centralshoal of Wuhan: Implication for Sedimentary Environment Change in the Middle Reaches of the Yangtze River
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摘要: 利用多磁性参数(包括质量磁化率、频率磁化率、饱和等温剩磁、退磁系数以及热磁曲线)及磁组构分析，以长江中游武汉天兴洲近代河流沉积物为研究对象, 探讨了近100年以来沉积物磁性参数变化特征及其对长江中上游水文变化及气候环境的指示.结果表明，上部组合带(0.60~1.50 m)和下部组合带(2.40~3.30 m)沉积物的磁性载体以亚铁磁性矿物磁铁矿为主，同时存在少量较稳定的不完整反铁磁性物质，中部(1.50~2.40 m)亚铁磁性矿物相对较少，且剖面上部沉积物的超顺磁(SP)颗粒对沉积物χ贡献较大.整个沉积剖面自下而上磁性矿物含量呈“C”字型变化，反映了“软”-“硬”-“软”的磁性特性.沉积物磁组构组合带研究显示，历史时期沉积环境水动力强度、颗粒排列有序化程度以及长江流速发生了明显的变化，沉积环境水动力强度经历了“不稳定”－“稳定”－“不稳定”的变化过程，反映了长江古水文状况的变化.近代沉积物磁性特征变化格局与1900年以来以来长江中上游“暖湿”-“温凉”-“暖湿”气候环境变化和“强降水”-“弱降水”-“强降水”以及长江汉口站流量变化过程相吻合.这一研究成果为深刻认识历史时期长江流域气候环境变迁其及对长江古水文和沉积环境的影响提供了重要的参考资料.Abstract: Multi-proxy of environmental magnetism (such as mass susceptibility, frequency dependent susceptibility, saturation isothermal, demagnetizing factor and thermalmagnetic curve) and magnetic fabric parameters derived from the recent sediments at Tianxing Centralshoal of Wuhan are employed to reconstruct the history of paleo-hydrology and climate changes in the mid-upper reaches of the Yangtze River. The assemblage zones of multi-proxy of environmental magnetism indicate that both upper (0.60-1.50 m) and lower (2.40-3.30 m) zones are dominated by the ferromagnetic magnetite. The upper zone is marked by the superparamagnetic grains, which make greater contributions to the mass susceptibility. The percentage of antiferromagnetic minerals in the middle zone (1.50-2.40 m) increases in inverse proportion to the percentage of the ferromagnetic. Therefore, the depth variation of the magnetic mineral contents is like letter C reflecting the magnetic characteristics of "SOFT", "hard" and "SOFT" throughout the section. The analysis on the magnetic fabric parameters demonstrates that hydrodynamic intensity of sedimentary environment, ordering degrees of particle arrangement, and flow velocity of the Yangtze River have undergone significant changes in the past 100 years, which is related to the paleo-hydrological change of the Yangtze River. Variation patterns of magnetic properties in the recent sediments are consistent with the climate change and discharge change at Hankou Station. Especially, hydrodynamic intensity of sedimentary environment has changed from unstable to stable, then unstable, corresponding to the temperature and precipitation changes from hot-wet to cool-dry and hot-wet. Our research has provided significant evidence for further understanding the influence of climate change on the paleo-hydrology and sedimentary environment of the Yangtze River in the historical period.
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Key words:
- sediments /
- environmental magnetism /
- magnetic fabric parameters /
- geophysics
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图 1 长江中游武汉天兴洲地理位置及采样地点分布
Fig. 1. Map showing the sampling site at the Tianxing Centralshoal of Wuhan, the middle reaches of Yangtze River
图 2 长江中游天兴洲沉积物A剖面磁性参数随深度变化特征
Fig. 2. Depth variation of magnetic parameters of sediments at the Tianxing Centralshoal of Wuhan, the middle reaches of Yangtze River
图 3 代表性样品的χ-T曲线
粗(细)线分别代表加热(冷却)曲线
Fig. 3. χ-T variation curve of certain representative samples
图 4 代表性样品的SIRM充磁曲线(a)和AF退磁曲线(b)
Fig. 4. (a) SIRM charging magnetization curve of certain representative samples and (b) AF demagnetization curve of certain representative samples
图 5 长江中游天兴洲沉积物B剖面磁组构参数随深度变化特征
Fig. 5. Depth variation of magnetic fabric parameters in the sediments at the Tianxing Centralshoal of Wuhan, the middle reaches of Yangtze River
图 6 长江中游天兴洲沉积物磁化率张量主方向的赤平投影
方块、三角、圆点分别表示κ1、κ2、κ3的主方向
Fig. 6. Equatorial plane projection map of major direction of magnetic susceptibility tensor in the sediments at the Tianxing Centralshoal of Wuhan, the middle reaches of Yangtze River
图 7 Fs、κ1轴方位角随深度的变化与汉口站流量(Chen et al., 2001)和近100年长江上游降水(图 7d, A)与温度(图 7d, B)曲线(陈家其等，2006)对比(图 7a中虚线为现代流速)
Fig. 7. Azimuth angle variation of Fs and κ1 axle with depth and its correlation with discharge volumes at Hankou station (from Chen et al., 2001), and precipitation (Fig. 7d, A) and temperature (Fig. 7d, B) curves (from Chen et al., 2006), in the upper reaches of the Yangtze River during the past 100 years (Dashed line in Fig. 7a represents current flow velocity)
表 1 长江中游武汉天兴洲采样剖面A岩性
Table 1. Lithology description of sampling section A at the Tianxing Centralshoal of Wuhan, the middle reaches of Yangtze River
分层 岩性 采样点数/样品数 深度(m) 层厚(m) ① 耕土 1/3 0.20~0.60 0.40 ② 粉砂质粘土 6/18 0.60~0.95 0.35 ③ 粘土质细砂 6/17 0.95~1.25 0.30 ④ 粉砂质粘土 8/19 1.25~1.65 0.40 ⑤ 粉细砂 3/9 1.65~1.85 0.20 ⑥ 粘土质粉砂 2/6 1.85~1.95 0.10 ⑦ 粉细砂 14/40 1.95~2.65 0.70 ⑧ 粘土质粉砂 14/39 2.65~3.30 0.65 
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Chen, J.Q., Shi, Y.F., Zhang, Q., et al., 2006. Climatic background for historical flood of 1 860, 1 870 during past 500 years in the Upper Yangtze River basin. Journal of Lake Sciences, 18(5): 476-483 (in Chinese with English abstract). doi: 10.18307/2006.0506 Chen, Z.Y., Li, J.F., Shen, H.T., et al., 2001. Yangtze River of China: historical analysis of discharge variability and sediment flux. Geomorphology, 41(2-3): 77-91. doi: 10.1016/S0169-555X(01)00106-4 Hilton, J., Lishman, J.P., Chapman, J.S., 1986. Magnetic and chemical characterization of a diagenetic magnetic mineral formed in the sediments of productive lakes. Chemical Geology, 56(3-4): 325-333. doi: 10.1016/0009-2541(86)90012-4 Hu, S.Y., Deng, C.L., Appel, E., et al., 2001. Environmental implication of magnetic property on lacustrine sediments. Chinese Science Bulletin, 46(17): 1491-1494 (in Chinese). doi: 10.1360/csb2001-46-17-1491 Liu, Q.S., Deng, C.L., 2009. Magnetic susceptibility and its environmental significances. Chinese Journal of Geophysics, 52(4): 1041-1048 (in Chinese with English abstract). http://www.oalib.com/paper/1568814 Liu, Q.S., Zeng, Q.L., Yang, T., et al., 2009. Magnetic properties of street dust from Chibi city, Hubei Province, China: its implications for urban environment. Journal of Earth Science, 20(5): 848-857. doi: 10.1007/s12583-009-0071-7 Lu, S.G., Dong, R.B., Yu, J.Y., et al., 1999. Magnetic measurement characterisation of red earth profile in eastern China and its environmental implications. Chinese Journal of Geophysics, 42(6): 764-771 (in Chinese with English abstract). http://d.wanfangdata.com.cn/Periodical/dqwlxb199906006 Niu, J.L., Yang, Z.S., Li, Y.H., et al., 2008. The characteristics of the environmental magnetism in sediment from the river mouths of the Changjiang River and the Huanghe River and their comparison study. Marine Sciences, 32(4): 24-30 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-HYKX200804004.htm Thompson, R., Oldfield, F., 1986. Environmental magnetism. Allen and Unwin, London. Wang, H., Zheng, X.M., Wang, X.Y., et al., 2008. Environmental magnetic properties of sediments from middle and lower reaches of Changjiang River. Quaternary Sciences, 28(4): 640-648 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DSJJ200804016.htm Wang, H.Q., Zhang, S.H., Li, H.Y., 2008. The rock magnetic behaviors and its environmental implication of surface sediments in Beianhe, Beijing. Chinese Science Bulletin, 53(13): 1589-1597 (in Chinese). doi: 10.1360/csb2008-53-13-1589 Wang, Y.J., Jiang, T., Shi, Y.F., 2005. Changing trends of climate and runoff over the upper reaches of the Yangtze River in 1961-2000. Journal of Glaciology and Geocryology, 27(5): 709-714 (in Chinese with English abstract). http://d.wanfangdata.com.cn/Periodical/bcdt200505014 Wang, Z., Chen, Z.Y., Shi, Y.F., et al., 2007. The conformation of underlying bed sand wave and its dynamic mechanism in Wuhan-Hekou section, upper and middle water of Yangtze River. Science in China (Series D), 37(9): 1223-1234 (in Chinese). http://www.researchgate.net/publication/309455757_The_conformation_of_underlying_bed_sand_wave_and_its_dynamic_mechanism_in_Wuhan_Hekou_section_upper_and_middle_water_of_Yangtze_River Wang, Z.B., Yang, S.Y., Li, P., et al., 2006. Detrital mineral compositions of the Changjiang River sediments and their tracing implications. Acta Sedimentologica Sinica, 24(4): 570-578 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=cjxb200604015 Wang, Z.B., Yang, S.Y., Wang, R.C., et al., 2007. Magnetite compositions of Changjiang River sediments and their tracing implications. Geochimica, 36(2): 176-184 (in Chinese with English abstract). http://www.researchgate.net/publication/281582197_Magnetite_compositions_of_Changjiang_River_sediments_and_their_tracing_implications Worm, H.U., Banerjee, S.K., 1987. Rock magnetic character in Cretaceous-Tertiary boundary. Geophysical Research Letter, 14(11): 1083-1086. doi: 10.1029/GL014i011P01083 Yan, G.L., 1996. The application of rock magnetic susceptibility anisotropy in geology. China University of Geosciences Press, Wuhan, 1-20 (in Chinese). Yang, S.Y., Jiang, S.Y., Ling, H.F., et al., 2007. Sr-Nd isotopic compositions of the Changjiang sediments: implications for tracing sediment sources. Science in China (Series D), 50(10): 1556-1565. doi: 10.1007/s11430-007-0052-6 Yang, T., Liu, Q.S., Chan, L.S., et al., 2009a. Magnetic investigation of heavy metals contamination in urban topsoils around the East Lake, Wuhan city, China. Geophysical Journal International, 171(2): 603-612. doi: 10.111/j.1365-246X.2007.03558.x Yang, T., Liu, Q.S., Zeng, Q.L., et al., 2009b. Environmental magnetic responses of urbanization processes: evidence from the lake sediments in East Lake, Wuhan, China. Geophysical Journal International, 179(2): 873-886. doi: 10.1111/j.1365-246X.2009.04315.x Yang, T., Liu, Q.S., Li, H.X., et al., 2010. Anthropogenic magnetic particles and heavy metals in the road dust: magnetic identification and its implications. Atmospheic Environment, 44(9): 1175-1185. doi: 10.1016/j.atmosenv.2009.12.028 Yuan, X.C., 1991. The principle of palaeomagnetism and its application. Geological Publishing House, Beijing, 34-50 (in Chinese). Zhang, W.G., Dai, X.R., Zhang, F.R., et al., 2007. Magnetic properties of sediments from the Chaohu Lake for the last 7 000 years and their implications for the evolution of Asian monsoon. Quaternary Sciences, 27(6): 1053-1062 (in Chinese with English abstract). http://d.old.wanfangdata.com.cn/Periodical/dsjyj200706021 Zhang, Y.F., Li, C.A., Chen, L., et al., 2009. Magnetic fabric characters of sand-dune sediments and its paleowind field in the middle reaches of Yangtze River. Chinese Journal of Geophysics, 52(1): 150-156 (in Chinese with English abstract). doi: 10.1002/cjg2.1330/pdf Zhou, L.C., Liu, S.H., 2005.2-D numerical simulation of flow field in Tianxingzhou reach on Yangtze River. Engineering Journal of Wuhan University (Engineering Edition), 38(1): 30-33 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-WSDD200501007.htm 陈家其, 施雅风, 张强, 等, 2006. 从长江上游近500年历史气候看1860、1870年大洪水气候变化背景. 湖泊科学, 18(5): 476-483. doi: 10.3321/j.issn:1003-5427.2006.05.006 胡守云, 邓成龙, Appel, E., 等, 2001. 湖泊沉积物磁学性质的环境意义. 科学通报, 46(17): 1491-1494. doi: 10.3321/j.issn:0023-074X.2001.17.020 刘青松, 邓成龙, 2009. 磁化率及其环境意义. 地球物理学报, 52(4): 1041-1048. doi: 10.3969/j.issn.0001-5733.2009.04.021 卢升高, 董瑞斌, 俞劲炎, 等, 1999. 中国东部红土的磁性及其环境意义. 地球物理学报, 42(6): 764-771. doi: 10.3321/j.issn:0001-5733.1999.06.006 牛军利, 杨作升, 李云海, 等, 2008. 长江与黄河河口沉积物环境磁学特征及其对比研究. 海洋科学, 32(4): 24-30. https://www.cnki.com.cn/Article/CJFDTOTAL-HYKX200804004.htm 王红强, 张世红, 李海燕, 2008. 北京北安河地表沉积物的岩石磁学特征及环境意义. 科学通报, 53(13): 1589-1597. doi: 10.3321/j.issn:0023-074X.2008.13.016 王辉, 郑祥民, 王晓勇, 等, 2008. 长江中下游干流河底沉积物环境磁性特征. 第四纪研究, 28(4): 640-648. doi: 10.3321/j.issn:1001-7410.2008.04.016 王艳君, 姜彤, 施雅风, 2005. 长江上游流域1961—2000年气候及径流变化趋势. 冰川冻土, 27(5): 709-714. 王哲, 陈中原, 施雅风, 等, 2007. 长江中下游(武汉-河口段)底床沙波型态及其动力机制. 中国科学(D辑), 37(9): 1223-1234. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK200709010.htm 王中波, 杨守业, 李萍, 等, 2006. 长江水系沉积物碎屑矿物组成及其示踪意义. 沉积学报, 24(4): 570-578. doi: 10.3969/j.issn.1000-0550.2006.04.015 王中波, 杨守业, 王汝成, 等, 2007. 长江河流沉积物磁铁矿化学组成及其物源示踪. 地球化学, 36(2): 176-184. 阎桂林, 1996. 岩石磁化率各向异性在地学中的应用. 武汉: 中国地质大学出版社, 1-20. 杨守业, 蒋少涌, 凌洪飞, 等, 2007. 长江河流沉积物Sr-Nd同位素组成与物源示踪. 中国科学(D辑), 37(5): 682-690. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK200705012.htm 张卫国, 戴雪荣, 张福瑞, 等, 2007. 近7000年巢湖沉积物环境磁学特征及其指示的亚洲季风变化. 第四纪研究, 27(6): 1053-1062. doi: 10.3321/j.issn:1001-7410.2007.06.021 张玉芬, 李长安, 陈亮, 等, 2009. 长江中游砂山沉积物磁组构特征及其指示的古风场. 地球物理学报, 52(1): 150-156. https://www.cnki.com.cn/Article/CJFDTOTAL-DQWX200901019.htm 周龙才, 刘士和, 2005. 长江天兴洲河段平面二维流场数值模拟. 武汉大学学报(工学版), 38(1): 30-33. -
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