Primary Study on Quantitative Reconstruction of Middle-Late Eocene Climate in Jianghan Basin
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摘要: 依据江汉盆地明钾1孔中、晚始新统系统的孢粉资料, 应用化石孢子花粉亲缘植物的生态位估算孢粉组合所反映的古气候特征.气候参数曲线的变化趋势显示江汉盆地始新世中期气候参数与现今北纬2 2°~ 2 6°的数值相接近, 为中-南亚热带湿润半湿润气候.晚期气温较前期低1~ 4℃, 相当于现今北纬2 3°~ 2 8°处的数值, 为北-中亚热带气候.但是, 气候构型与现今截然不同, 具有气温高、年较差小、降水波动大的特点.始新世中期1月均温比今高5~ 9℃, 表明冬季风作用尚不明显, 晚期略显冬季风的影响.气候的降温发生在孔深2 10 0m处, 主要表现为1月均温的下降和年较差增长, 因而孢粉组合中落叶阔叶树种增多.年降水量波动强烈, 一般于30 0~ 170 0mm之间, 这有利于盐类矿物的迁移和堆积.降水量低于10 0 0mm时, 麻黄灌木花粉增多, 且与膏盐堆积深度相一致.高山深盆的干热环境是本区盐类矿物沉积的主要原因, 年降水量波动强烈且偏低, 有利于盐类的持续堆积, 从而有别于现今西北地区的盐类堆积.Abstract: This paper reports our primary effort in quantitatively reconstructing paleoclimate based on the niche of the affinity parent plants in the stratigraphic pollen record. Eocene pollen data come from our former study on the core Mingjia 1 in the Jianghan basin. The changing trend in the parameter curve of climate shows that the middle Eocene climate in the Jianghan basin is more or less comparable with that of the present 22°-26°N, reflecting a humid, semi humid central southern subtropical climate. The annual temperature then declined 1-4 ℃ lower at the late Eocene, approximately equal to the present 23°-28°N of northern central subtropical climate. However, the climate composite at that time was different from the present one, and was characterized by higher temperature, small annual range, and big fluctuation in precipitation. The January average temperature in the middle Eocene was 5-9 ℃ higher than that of today, indicating that there was no winter monsoon influence in the middle Eocene, though it may have partly happened in late Eocene. Major temperature decline is recognized at depth 2 100 m of the core, as was indicated by the decline in January average temperature and an increase in annual range. It is also indicated by the increase of the deciduous broad leaved types in the pollen assemblage. The sharp fluctuation in the annual precipitation, raging from 300 to 1 700 mm, was favorable for the migration and accumulation of salty deposits. When the precipitation was lower than 1 000 mm, ephedra shrub increased, which happened in the same depth with the salty deposit. It is deduced that the dry and hot environment in the high mountain and deep basin could have been the main reason for the formation of the salty deposit in the core. The annual precipitation was not very lower at that time, and this is different from the present salty deposit in Northwest China.
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图 1 江汉盆地明钾1孔主要孢粉图式
Fig. 1. Diagram showing main pollen types in Jianghan basin
1.Gymnospermae; 2.Angiospermae; 3.Pterdophyta; 4.Pimuspollenites+Abietineaepollenites; 5.Keteleeriaepollenites+Podocarpidites; 6.Cedripites; 7.Taxodiaceaepollenites; 8.Sabapollenites+Cycadopites; 9.Ephedripites; 10.Quercoidites; 11.Cupuliferoipollenites; 12.Ulmipollenites; 13.Betulaceoipollenites; 14.Euphorbiacites+Rhoipites; 15.Peltandripites+Santalumidites; 16.Nyssapollenites+Rutaceoipollis; 17.Magnolipollis
表 1 江汉盆地始新世中、晚期气候参数上、下限的一般变化幅度
Table 1. General changing range on upper and lower limits of middle-late Eocene climatic parameter in Jianghan basin
表 2 江汉盆地始新世中、晚期气候参数的一般变化幅度
Table 2. General changing range on middle-late Eocene climatic parameter in Jianghan basin
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[1] 孔昭宸, 杜乃秋, 张义君, 等. 句容宝华山山龙眼化石植物群发现及其气候学和植物学上的意义[J]. 第四纪研究, 1991, 4: 326-335. doi: 10.3321/j.issn:1001-7410.1991.04.004KONG Z C, DU N Q, ZHANG Y J, et al. Discovery of Helicia fossil florule and sporo-pollen assemblage of Baohuashan in Jurong County and its climatic and botanic significance[J]. Quaternary Sciences, 1991, 4: 326-335. doi: 10.3321/j.issn:1001-7410.1991.04.004 [2] Birka H JB. Quaternary palaeoecology[M]. London: Edward Nold, 1980.231-258. [3] 李承森, 王宇飞, 孙启高. 定量分析第三纪以来环境变化的新方法——特有种气候分析法[J]. 植物学报, 2001, 43 (2): 217-220. doi: 10.3321/j.issn:1672-9072.2001.02.018LI C S, WANG Y F, SUN Q G. Climate analysis of endmic species-anovel method for quantitative analysis of global climate change since Tertiary[J]. Acta Botanica Sinica, 2001, 43 (2): 217-220. doi: 10.3321/j.issn:1672-9072.2001.02.018 [4] 沈才明, 唐领余. 青藏高原南部上新世花粉植物群及古气候[J]. 地层学杂志, 1992, 16(4): 264-269. https://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ199204002.htmSHEN C M, TANG L Y. Quaternary palynoflora and palaeoclimatein the southern Qingha-i Xizang plateau[J]. Journal of Stratigraphy, 1992, 16(4): 264-269. https://www.cnki.com.cn/Article/CJFDTOTAL-DCXZ199204002.htm [5] Guiot J P. A12 000 year continental climate reconstruction from two European pollen records[J]. Nature, 1989, 338 (23): 209-313. [6] 童国榜, 吴锡浩, 童琳, 等. 太白山最近1 000年的孢粉记录与古气候重建尝试[J]. 地质力学学报, 1998, 4 (4): 58-63.TONG G B, WU X H, TONG L, et al. Spore-pollen records and tentative paleoclimate reconstruction in Taibai mountain in the last1 000 years[J]. Journal of Geomechanics, 1998, 4(4): 58-63. [7] 中国第四纪孢粉数据库小组. 中国全新世(6 ka)和末次盛冰期(18 ka)生物群区的重建[J]. 植物学报, 2000, 42 (11): 1201-1209. doi: 10.3321/j.issn:1672-9072.2000.11.018Members of China Quaternary Pollen Data Base. Pllenbased biome reconstruction at Middle Holocene (6 ka)and last glacial maximum (18 ka)in China[J]. Acta Botanica Sinica, 2000, 42(11): 1201-1209. doi: 10.3321/j.issn:1672-9072.2000.11.018 [8] 宋长清, 孙湘君. 花粉-气候因子转换函数建立及其对古气候因子定量重建[J]. 植物学报, 1997, 39 (6): 554-560. https://www.cnki.com.cn/Article/CJFDTOTAL-ZWXB199706012.htmSONG C Q, SUN X J. Establishment of transferfunctions of the pollen-climatic factors in northern China and the quantitative climatic reconstruction at dj core[J]. Acta Botanica Sinica, 1997, 39(6): 554-560. https://www.cnki.com.cn/Article/CJFDTOTAL-ZWXB199706012.htm [9] Webb R S, Anderson K H, Webb T. Pollen response-surface estimates of Late-Quaternary changes in the moisture balance of the northeastern United States[J]. Quat Res, 1993, 40: 213-227. doi: 10.1006/qres.1993.1073 [10] 叶得泉, 钟春, 姚益民, 等. 中国油气区第三系(I)总论[M]. 北京: 石油工业出版社, 1993.232-241.YE D Q, ZHONG X C, YAO Y M, et al. Tertiary in petroliferous regions of China (Ⅰ), introduction[M]. Beijing: Petroleum Industry Press, 1993.232-241. [11] 张师本, 沈后, 曲新国, 等. 中国油气区第三系(V)鄂豫皖油气区分册[M]. 北京: 石油工业出版社, 1993.191- 195.ZHANG S B, SHEN H, QU X G, et al. Tertiary in petroliferous regions of China (Ⅴ): the Hube-i HenanAnhui region[M]. Beijing: Petroleum Industry Press, 1993.175-179. [12] 童国榜, 郑绵平, 袁鹤然, 等. 江汉盆地始新世中、晚期的孢粉合特征及其环境意义[M]. 地球学报, 2001, 22 (1): 73-78.TONG G B, ZHENG M P, YUAN H R, et al. A study of middle and late Eocene palynological assemblages in Jianghan basin and their environmental significance[J]. Acta Geoscientia Sinica, 2001, 22(1): 73-78. [13] 刘光明. 中国自然地理图集[M]. 第三版. 北京: 中国地图出版社, 1998.37-112.LIU G M. Atlas of natural geography in China[M]. third edition. Beijing: China Cartographic Press, 1998. 37-112. [14] 李钜章. 现代地学数学模拟[M]. 北京: 气象出版社, 1994.124-126.LI J Z. Mathematical analogue on modern earth science [M]. Beijing: Meteorological Press, 1994.124-126. [15] 宋之琛. 中国孢粉化石[M]. 第一卷. 北京: 科学出版社, 1999.59-740.SONG Z C. Fossil spores and pollen of China[M]. Vol. 1. Beijing: Science Press, 1999.59-740. [16] 罗伦德. 重庆嘉陵江一级阶地孢粉分析及其晚全新世古气候的变化[J]. 海洋地质与第四纪地质, 1989, 9 (4): 69-85.LUO L D. Sporopollen analysis to one-step terrace of the Jialingjiang River in Chongqing city and its palaeoclimatic development during Late Holocene[J]. Marino Geology & Quaternary Geology, 1989, 9(4): 69-85. [17] 吴锡浩, 钱方, 兰朝玉. 北京延庆盆地早更新世古气候重建[A]. 见: 刘东生. 黄土、第四纪地质、全球变化[C]. 第一集. 北京: 科学出版社, 1990.47-61.WU X H, QIAN F, LAN C Y. Paleoclimatic reconstruction during the Early Pleistocene in the Yanqing basin, Beijing, China[A]. In: LIU D S, ed. Loess, Quaternary Geology and Global Change[C]. Part Ⅰ. Beijing: Science Press, 1990.47-61. [18] 孔昭宸, 杜乃秋, 席以珍. 北京一亿多年来植物群的发展和古气候的变迁[J]. 植物分类学报, 1976, 14 (1): 79-89.KONG Z C, DU N Q, XI Y Z, et al. Vegetational and climatic changes in Peking during the past one hundred million years[J]. Acta Phytotaxonomica Sinica, 1976, 14(1): 79-89. [19] 弗雷克斯L A. 地质时代的气候[M]. 赵希涛, 甄勇毅, 李文范, 译. 北京: 海洋出版社, 1984.232-262.Frakes L A. Climates throughout geologic time[M]. Tarnslated by ZHAO X T, ZHEN Y Y, LI W F. Beijing: China Ocean Press, 1984.232-262. [20] 黄赐璇, Pierre C. 我国东部花粉雨初探[J]. 地理研究, 2001, 20(1): 24-30. https://www.cnki.com.cn/Article/CJFDTOTAL-DLYJ200101003.htmHUANG C X, Pierre C. A tentative study of pollen rain in eastern China[J]. Geographical Research, 2001, 20 (1): 24-30. https://www.cnki.com.cn/Article/CJFDTOTAL-DLYJ200101003.htm