| 摘要 | 泥炭以发育广泛、连续沉积好、沉积速率大（可达1mm/a甚至更大）、记录丰富等特点,正成为过去全球变化研究的良好综合地质档案.参考冰芯、黄土、深海沉积物等中矿物固体的研究思路和方法,希望能对泥炭中可能存在的火山物质和其它风粉尘进行研究.在对吉林金川西大甸子泥炭样品的处理过程中,摸索出一套泥炭样品中固体物质（如火山物质）初步的处理、分析方法;并对金川西大甸子干玛珥泥炭沉积中部一段泥砂状物质进行鉴定,首次发现火山玻璃,判断这些泥砂物为火山灰砂.目前研究表明,泥炭纤维素的δ<'13>C序列能较好地反映古气候变化,那么泥炭中胡敏酸的δ<'13>C序列可否也能反映古气候变化,该文对此作了初步研究.用碱溶酸沉淀方法从泥炭中提取出所谓的胡敏酸,用燃烧法将胡敏酸、纤维素中的碳转化为CO<,2>气体,测定它们的稳定碳同位素组成（δ<'13>C）.与能较好地反映气候变化的纤维素δ<'13>C序列相比,胡敏酸的δ<'13>C序列反映气候变化不明显. |
| 其他摘要 | Peat with the characteristics of extensive growth, continous sediment, good accumulation rate (amount to lmm/a and even larger), plentiful recorded information, and so on, become a kind of excellent nature compositive geological archive which is important to the study on past global changes. Ice core, loess, deep sea sediments, and so on, contain a lot of solid minerals whose changing characters reflect the palaeoclimatic changes well. Just like the study of solid minerals in those sediments, this study was taken and in order to find volcanic materials and other breeze powder probably contained in peat, because these volcanic materials and other breeze powder may be the important information of palaeoclimatic changes or active volcanoes. In the course of handling the samples of peat which taken from Xidadianzi Jilinjinchuan, got the preliminary handling steps and analysis method of solid materials (such as volcanic materials) in peat. It is first time that volcanic glass has been foud after a section of substance like sants being identified which sediments in the middle of Jinchuan peat of Xidadianzi dry maar. The volcanic materials deposite in the closing environment of maar lake, the compositions simple, volcanic glass about 60%, over and above lmm compositions more and each sample contains same main elements and similar REE pattern and imcompatible elements pattern, suggesting that the volcanic materials deposited in-situ following the eruption of a near-source volcano. According to the chemical compositions and volcanic tepha not getting Xidaxianzi Jinchuan, the volcanic materials are impossible to come from the Tianchi volcano at Changbaishan, nor from the Jinlongdingzi volcano which erupted at about 1600 years ago. Because of their main chemical compositions and depletion in SiO_2, enrichment in alkalies, Na2O more of K_2O, REE pattern and imcompatible: elements pattern and Eu slight abnomiity similar to those of Longgang volcano group, the volcanic materials and those of Jinglongdingzi all derived directly from mantle sources with very limited evolution and crust contamination during the uplift of basaltic magma, and have the same basaltic magma-water volatile eruption. According to the age of the peat in which volcanic materials are contained, it is considered that the age of this possible earlier eruption of the Longgang volcano group is 15BC-AD26. So, it is must noticed that Longgang volcano group, this active volcanoes area, have two eruptions at least in Holocene: 2002 aBP-1976 aBP small eruption and Jinlongdingzi about 1600 aBP small eruption. It has known that 8 13C sequence of peat cellulose reflect palaeoclimate changes well, then whether the δ~(13)C sequence of humic acid in peat can reflect palaeoclimate changes or not, primary study was carried. Picked up humic acid with the method of
alkali-extraction and acid-depostion, transfered the carbon of humic acid and peat cellulose into the gas of CO_2 with burning method, then measured the stable carbon isotope ration (δ~(13)C in MAT-252. It is conclused that the δ~(13)C sequence of peat cellulose reflect palaeoclimate changes well, but those of humic acid in peat not distinctly. |
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