Knowledge Resource Center for Ecological Environment in Arid Area
| 磁化率和植物化石记录对第四纪沉积环境的古气候量化研究 | |
| 吕厚远 | |
| 出版年 | 1998 |
| 学位类型 | 博士 |
| 导师 | 刘东生 |
| 学位授予单位 | 中国科学院地质与地球物理研究所 |
| 中文摘要 | 本文通过对中国371个现代表土磁化率样品和153个现代表土植物硅酸体样品的分析以及120余种现代植物硅酸体形态学研究，初步掌握了表土磁化率、植物硅酸体组合随气候环境变化的规律，以及表土植物硅酸体组合与现代植被类型的关系。在此基础上，重点研究了黄土高原第四纪，特别是末次间冰期以来古植被类型的演替、季节性气候变化的规律以及古降水量的空间格局变化。通过孢粉、沉积物干密度、磁化率等指标研究了湛江湖光岩玛珥湖高分辨率的沉积系列，提取出短尺度的气候变化信息。主要研究结果和认识如下：1、植物、特别是C4植物的生长对土壤磁化率有重要的贡献，不仅是植物本身含有使土壤磁性增强的物质，而且植物根系生长营造的微环境为土壤强磁性矿物的形成提供了条件。2、自然发育的土壤和受工业化污染的土壤磁化率特征有明显的差异，受工业化污染的土壤高、低频磁化率的差值不大，但土壤磁化率值非常高，而自然发育的土壤高、低频磁化率的差值一般随磁化率的增高而增高。3、在黄土高原及周边地区，表土磁化率随年降水量、年均温度的增高而增高，当年降水量超过1100mm、年均温度超过15℃左右，表土磁化率随年降水量和年均温度的增高而降低。在华南地区，母质对土壤磁化率的影响超过了气候带对土壤磁化率的影响。4、不同的植物硅酸体类型在表土中的分布受气候环境的影响是明显的，15组表土植物硅酸体组合对应了15类现代草地类型。5、在黄土高原南部地区，L2顶部沉积时期普遍发育了荒漠和荒漠化植被类型，而S1沉积时期以来，自西向东植被类型的分布有强的区域性。6、通过表土样品分别建立了土壤磁化率、植物硅酸体与气候参数的定量关系，在南剖面的古气候估算中，两者估算范围是吻合的。7、利用黄土高原几个剖面的磁化率资料，估算了120万年以来以及15万年以来年降水量和年均温度的变化。恢复了末次间冰期以来主要时间段年降水量的空间分布格局，探讨了该区季节性气候变化的特点。8、通过对湖光岩玛珥湖孢粉、沉积物干密度的分析，研究了干密度变化的气候意义，提取出末次冰期以来短尺度的气候变化曲线。 |
| 英文摘要 | In this study, magnetic susceptibility (MS) and opal phytolith were analyzed on the samples taken from modern surface soils, and were used as proxy indicators of physical and biological records. Totally, 371 MS samples and 153 phytolith samples, collected from many categories of modern soils in China, and more than 120 phytolith assemblages from modern plants were investigated. The purposes of this study are (1) to find a better relationship between magnetic susceptibility of the modern soils and present-day climate parameters such as temperature and precipitation, (2) to establish a better relationship between phytolith associations and vegetation types, and hence the relation with climate factors, (3) to estimate paleoclimate parameters based on MS and phytolith records of the loess paleosol sequence in the Loess Plateau using the climofunctions obtained from the regression analysis of the modern analogues, (4) to set a high-resolution maar lake sequence on the basis of the proxy data of spore-pollen, MS, and dry density of lake sediments. This paper focuses on the vegetation successions in the Loess Plateau since the last interglaciation, the seasonal climate variations reflected by phytolith association, and the spatial pattern of paleoprecipitation distribution reconstructed both from MS and phytolith climofunctions. The main results and conclusions are presented as following: 1. Plants, especially C4 plants, have an important contribution to the increase of soil MS. The plants contain the materials enhancing MS, as well make the microhabitat enhance the soil MS. 2. The soils with industrial pollution are different in magnetic property from natural soils. The high and low frequency susceptibilities of industrial pollution soil samples are nearly at same level, but MS value is very high. However, the differences between high and low frequency susceptibilities of the natural developed soil samples vary with MS values. 3. In the Loess Plateau and its surrounding areas, the MS of the modern soil samples increases with annual mean temperature (MAT) and annual mean precipitation (MAP). A contrary relationship exists for the sothern China where MAT exceeds 15 ℃ and MAP exceeds 1100 mm, of which the MS of the modern soils decrease with increasing MAT and/or MAP. The parent soils in the southern China may have played a more important role on the soil MS than for the climate conditions. 4. Distribution of phytolith associations in the modern soils is apparently influenced by local climate condition, 15 phytolith assemblages correspond to 15 types of grasslands. 5. In the southern Loess Plateau, the vegetation at the end of the L2 loess stage was desertic or steppe-desertic. The distribution pattern of vegetation in the southern Loess Plateau remarkably changed since the beginning of the last interglacial period. 6. Through the study of MS and phytolith of the modern soils and related meteorological data, author have established the quantitative relationships between MS and climate parameters, phytolith and climate parameters, respectively. The paleoclimatic parameters since the last interglacial, estimated from both proxy records of Weinan loess section, are nearly consistent. 7. Using MS records from different loess sections, author has made the estimates of MAT and MAP for the last 1.2 Ma and 105 Ka, respectively. Spatial pattern of MAP distribution has been reconstructed also. Seasonal climatic variations in this region since the last interglacial has been investigated and discussed in detail. 8. Comparing pollen indices, author documented the climate significance of dry density of the sediment core from the Huguang maar lake in the southern China, and extracted short-scale climate information. |
| 中文关键词 | 土壤 ; 磁化率 ; 植物硅酸体 ; 孢粉 ; 黄土古土壤 ; 玛珥湖 ; 第四纪 ; 古气候 |
| 英文关键词 | magnetic susceptibility phytolith pollen modern soil loess-paleosol maar lake quaternary paleoclimate estimates |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源机构 | 中国科学院地质与地球物理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286215 |
| 推荐引用方式 GB/T 7714 | 吕厚远. 磁化率和植物化石记录对第四纪沉积环境的古气候量化研究[D]. 中国科学院地质与地球物理研究所,1998. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [吕厚远]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [吕厚远]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [吕厚远]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
