通过对获取的巢湖湖泊沉积岩芯的磁化率与粒度组合特征的分析,结合孢粉及相邻其它区域的环境考古资料,得出该岩芯柱样所反映的环境变化信息。结果表明:(1)巢湖湖泊沉积物磁化率曲线在117 cm以下总体上比较平稳而略有下降,117 cm以上人类活动所导致的侵蚀作用加剧使得磁化率值异常升高;(2)本岩芯柱样117 cm以下样品的磁化率强度与粘土的百分比含量呈正相关,而与粉砂组分的百分比含量成负相关;(3)根据磁化率与粒度组合变化特征,结合孢粉分析及全新世以来区域气候变化背景,9 870 Cal a B.P.以来的巢湖流域古气候环境演变可以划分6个不同的时期:9 870~7 000 Cal a B.P.,气候呈温和略干的特点;7 000~4 750 Cal a B.P.,气候温暖湿润;4 750~2 170 Cal a B.P.,流域气候温和干燥,巢湖湖盆局部地区可能出露水面以上;2 170~1 040 Cal a B.P.,气候总体上温和湿润,但是冷暖波动明显;1 040~2 00 Cal a B.P.流域处在温凉稍湿的时期,人类活动逐渐加强;200 Cal a B.P.至今,流域总体上处于相对温暖湿润阶段。
A typical lake sediment core from Chaohu Lake was chosen for this study. The vertical distribution of magnetic susceptibility and grain size in the sediments was determined. Based on the analyses of magnetic susceptibility and grain size of the core samples from Chaohu Lake, the paper has probed into the characteristics and environmental significance of magnetic susceptibility and grain size. The results show that from 490 cm to 117 cm, the curves of magnetic susceptibility are stable on the whole, which dropped slightly; from 117cm to top, the increased human activity makes magnetic susceptibility increasing obviously. The magnetic susceptibility is positive proportional to the contents of fine sand, and reversal proportional to the contents of coarse sand and organic materials. By means of magnetic susceptibility and grain size analyses, combined with pollen and the background of global climate change, regional palaeoclimatic changes were divided into six periods since 9870 cal yr B.P.: (1) mild and moderately dry period of 9870-7000 cal yr B.P.; (2) warm and humid period of 7000-4745 cal yr B.P.; (3) warm and dry period of 4745-2170 cal yr B.P.; (4) mild and humid period of 2170-1040 cal yr B.P., and during which climate fluctuated acutely; (5) cool and moderately humid period of 1040-200 cal yr B.P., climate fluctuate gently; (6) mild and humid period of 200 cal yr B.P. to nowadays.
[1] Thompson R, Oldfield F. Environmental Magnetism[M]. London: George Allen & Unwin, 1986:1-83.
[2] 王俊达.第四纪沉积物的古地磁研究[J].第四纪研究,1992,13(1):39~44.
[3] 王君波,朱立平.藏南沉错沉积物的粒度特征及其古环境意义[J].地理科学进展, 2002,21(5): 459~467.
[4] 曹建廷,王苏民,沈 吉,等.近千年来内蒙古岱海气候环境演变湖泊沉积记录[J].地理科学, 2000,20(5): 391~396.
[5] 羊向东,王苏民,沈 吉,等.近0.3 ka来龙感湖流域人类活动的湖泊环境响应[J].中国科学(D辑), 2001,31(12):1031~1038.
[6] 王乃昂,李吉均,曹继秀,等.青土湖近6 000年来沉积气候记录研究[J].地理科学, 1999,19(2): 119~124.
[7] 旺 罗,刘东生,韩家懋,等.中国第四纪黄土环境磁学研究进展[J].地球科学进展,2000,15(3):335~341.
[8] Heller F, Liu T S. Magnetostratigraphical dating of Loess deposits in China[J]. Nature, 1982, 300:431-433.
[9] 张振克,吴瑞金,王苏民.岱海湖泊沉积物频率磁化率对历史时期环境变化的反映[J].地理研究,1998,17(3):297~302.
[10] 杨晓强,李华梅.泥河湾盆地沉积物磁化率及粒度参数对沉积环境的响应[J].沉积学报,1999,17(增刊):763~768.
[11] 贾铁飞,戴雪荣,张卫国,等.全新世巢湖沉积记录及其环境变化意义[J].地理科学, 2006,26(6):706~711.
[12] 王心源,何 慧,钱玉春,等.从环境考古角度对古居巢国蠡测[J].安徽师范大学学报(自然科学版),2005,28(1):97~102.
[13] GAO Chao, Wang Xinyuan, YANG Zedong, LU Yingcheng, He Hui. Causes and Countermeasures for Chaohu Lakeshore Collaps[J].Chinese Geographical Science,2005,15(1):88-93.
[14] 吴跃东,江来利,储东如,等.大别山造山带与安徽沿江中新生代盆地盆山耦合关系[J].中国地质,2003,30(3):286~292.
[15] 钱存超,路玉林,刘丽利,等.大别山两期镁铁质-超镁铁质岩特征及成因讨论[J].火山地质与矿产,2001,22(4):269~277.
[16] 夏林益,王心源,张广胜.皖西丰乐河流域水土流失及防治对策[J].水土保持研究,2006,13(3):162~164.
[17] 屠清英,顾丁锡.巢湖——富营养化研究[M].北京:中国科学技术大学出版社,1990:64.
[18] 谢红霞,张卫国,顾成军,等.巢湖沉积物磁性特征及其对沉积动力的响应[J].湖泊科学,2006,18 (1):43~48.
[19] 高 超,王心源,杨则东,等.巢湖崩塌岸成因初步研究[J].水土保持研究,2005,12(2):49~51.
[20] 赵景波,蔡晓薇,王长燕.西安高陵渭河近120年来的洪水演变[J].地理科学,2007,27(2):225~230.
[21] 朱江玲,刘鸿雁,王红亚.河北坝上地区湖泊沉积物记录的中全新世干旱气候[J].地理科学,2007,27(3):380~384.
[22] 史 威,朱 诚,王富葆,等.宁镇及宜溧地区全新世中晚期典型沉积相与5 700 a B.P.前后的气候突变事件[J].地理科学,2007,27(4):512~518.
[23] 朱西德,王振宇,李 林,等.树木年轮指示的柴达木东北缘近千年夏季气温变化[J].地理科学,2007,27(2):256~260.
[24] 谢远云,李长安,王秋良,等.江汉平原近3 000年来古洪水事件的沉积记录[J].地理科学,2007,27(1):81~84.
[25] 吴瑞金.湖泊沉积物的磁化率、频率磁化率及其古气候意义——以青海湖、岱海近代沉积为例[J].湖泊科学,1993,5(2):128~135.
[26] 黄 润,朱 诚,王升堂.天堂寨泥炭地层磁化率、Rb/Sr值及反映的古气候意义[J].地理科学,2007,27(3):385~389.
[27] Yu L Z, Oldfield F, Wu Y S et al. Paleoenvironmental implications of magnetic measurements on sediment core from Kunming Basin, South-west China[J]. Journal of Paleolimnology, 1990, 3: 95-110.
[28] 王 建,刘泽纯,姜文英,等.磁化率与粒度、矿物的关系及其古环境意义[J].地理学报,1996,51(2):155~163.
[29] 殷 勇,方念乔,王 倩,等.云南中甸纳帕海湖泊沉积物的磁化率及环境意义[J].地理科学,2002,22(4):413~419.
[30] 王开发.全新世温暖期中低温事件的初步研究[J].第四纪研究,1990,(2):168~174.
[31] Water Resources Bureau, Jiangsu Province. Disaster Tables of Flood & Drought in the Jiangsu Province over the Last 2000 Years. Nanjing: Water Resources Bureau of Revolutionary Committee, Jiangsu Province, 1976:26-47.
[32] Chu Ko-chen. A preliminary study on the climatic fluctuations during the last 5 000 years in China [J].Scientia sinica,1973,16(2):226-256.
[33] 邓成龙,袁宝印,胡守云,等.环境磁学某些研究进展评述[J].海洋地质与第四纪地质,2000,20(2):93~101.
[34] 蓝 勇.中国历史地理学[M].北京:高等教育出版社,2005.
[35] John Hilton. A simple model for the interpretation of magnetic records in lacustrine and ocean sediments[J]. Quaternary Research, 1987, 27:160-166.
