泥河湾虎头梁剖面孢粉、磁化率、粒度分析及其环境意义

发布时间：2018-01-20 03:59

本文关键词： 泥河湾虎头梁剖面中更新世末期孢粉分析磁化率粒度　出处：《河北师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文对泥河湾盆地虎头梁剖面进行了孢粉、粒度和磁化率分析。孢粉分析结果显示:乔木类型花粉主要有冷杉属(Abies)、云杉属(Picea)、松属(Pinus)、落叶松属(Larix)、栎属(Quercus)、桦木属(Betula)、榆属(Ul mus)、槭树属(Acer)、鹅耳枥(Carpinus)等;灌木花粉类型主要有胡桃属(Juglans)、麻黄(Ephedraceae)、白刺属(Nitraria)、胡颓子科(Elaeagnaceae)、马鞭草科(Verbenaceae)等;常见的草本植物花粉类型主要有蒿属(Artemisia)、菊科(Compositae)、藜科(Chennopodiaceae)、禾本科(Gramineae)、毛茛科(Ranunculaceae)、莎草科(Cyperaceae)、唐松草属(Thalictrum)、香蒲科(Typhaceae)、蓼科(Polygonaceae)等;蕨类孢子主要有盘星藻(Pediastraceae)、单缝孢(monolete spore)、水龙骨孢子(Polypodiaceae)、三缝孢(trilete spore)、中华蕨(Selaginella)等。根据孢粉组合百分含量的变化将剖面划分为4个阶段:孢粉带1,(深度1300~1210 cm):对应的时间区间为176.4~176.3ka B.P.,孢粉组合显示,此期间植被景观为以松属、冷杉、云杉暗针叶林为主的森林草原景观,气候凉湿;孢粉带2,(深度1210~990 cm):时间约为176.3~169.0ka B.P.,此时气候变得干燥,植被景观以干旱草原为主伴有小范围森林景观;孢粉带3,(990~830 cm):时间约为169.0~157.3ka B.P.,气候转为温暖半湿润,植被景观为以阔叶林为主的森林草原景观;孢粉带4,(830~700 cm):时间约为157.3~143.8ka B.P.,此阶段气候转为温凉半湿润,植被景观为以云杉、冷杉为主的森林草原景观。虎头梁剖面孢粉、粒度和磁化率数据结果综合显示,中更新世末期,气候由温凉半湿润向温干转变,再变为温暖半湿润,最后转变为温凉半湿润。气候干燥,湖泊水平面下降,山麓洪积物入侵,粗粒径组分百分含量增加,磁化率值出现峰值;气候湿润,湖泊水平面上升,湖泊扩张,细粒径组分百分含量增加,磁化率值降低。虎头梁剖面的孢粉、粒度和磁化率数据特征较好反映中更新世末期泥河湾盆地古植被、古气候和沉积环境的变化。
[Abstract]:The pollen, granularity and magnetic susceptibility of Hutouliang section in Nihewan Basin are analyzed. The results show that the main pollen types of Arbor are Abies Abiesus and Picea. Pinusus, Larix, Quercus, Betula, Ulmus and Acera. Carpinus Carpinus et al. The main pollen types of shrubs are Juglansa, Ephedraceaeae and Nitraria. Elaeagnaceaeae, Verbenaceaeae, etc.; The main pollen types of herbaceous plants are Artemisia Artemisia, Compositae and Chennopodiaceaeae. Gramineae, Ranunculaceaeae, Cyperaceaeae, Thalic trumpet. Typhaceaeae, Polygonaceaeae, et al. The main fern spores are Pediastraceaeus, monolete sporea and Polypodiaceaeae. Trilete sporea, Selaginella et al. According to the percentage change of sporopollen assemblage, the profile is divided into four stages: pollen belt 1. (the depth is 1 300 ~ 1210 cm ~ (-1)): the corresponding time interval is 176.4 ~ 176.3ka B.P. the sporopollen assemblage shows that the vegetation landscape during this period is pine and fir. The forest steppe landscape of Picea spruce dark coniferous forest, the climate is cool and wet; The sporopollen belt (depth 1210 ~ 990 cm ~ (-1): about 176.3 ~ 169.0ka B.P.), and the climate becomes dry. The vegetation landscape is mainly arid grassland with small forest landscape; The sporopollen belt was about 169.0157.3ka B.P., the climate changed to warm and semi-humid, and the vegetation landscape was the forest steppe landscape dominated by broad-leaved forest. The sporopollen belt is about 8307cm ~ (-1) cm ~ (-1): the time is about 157.3kA 143.8ka B.P. the climate changes to cool and semi-humid in this stage, and the vegetation landscape is spruce. The results of pollen, granularity and magnetic susceptibility data of Hutouliang section show that the climate changed from cool and semi-humid to warm and semi-humid in the late Middle Pleistocene. Finally, it changed into warm, cool and semi-humid climate, dry climate, the lake level decreased, the Alpine flood invaded, the percentage content of coarse particle size increased, and the magnetic susceptibility value reached the peak value. The climate is humid, the horizontal level of the lake rises, the lake expands, the content of fine particle fraction increases, and the magnetic susceptibility decreases. The characteristics of granularity and magnetic susceptibility data reflect the changes of paleoclimate paleoclimate and sedimentary environment in Nihewan basin in late Middle Pleistocene.
【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q914

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