过去11.5ka以来的北疆阿勒泰泥炭纤维素碳同位素记录及其可能的驱动机制

发布时间：2018-05-14 20:39

本文选题：阿勒泰 + 碳同位素　；参考：《兰州大学》2015年硕士论文

【摘要】：我们在阿尔泰山哈拉沙子湿地利用泥炭手钻采集到长度为742cm的泥炭岩芯,参考国内外树轮、湖泊和泥炭α-纤维素的提取流程,进行了大量的条件实验,最终建立起一套有效的适合泥炭岩芯样品的α-纤维素提取流程。利用建立起来的纤维素提取流程对从北疆阿尔泰山哈拉沙子湿地获取的泥炭岩芯样品进行了纤维素的提取和稳定碳同位素的分析测试,从而建立其在过去11.5ka以来的演化序列。为了明确阿勒泰泥炭纤维素碳同位素的气候环境指示意义,我们于2014年4-9月在该泥炭地开展了现代过程研究,包括：每个月在泥炭地收集当月的降水、泥炭地水、溪水样品和采集莎草样品,并在2000-2450m海拔梯度上采集莎草样品；7月在泥炭地采集了其他23种现代植物样品；8月在海拔2000m左右处采集4棵西伯利亚落叶松的12根树轮样芯。对采集的莎草、现代植物样品以及树轮样品进行了纤维素的提取和稳定碳同位素的分析测试工作。在阿勒泰泥炭地开展的现代过程研究结果表明,该泥炭地优势植物莎草(sedge),其纤维素碳同位素无论是在时间序列上还是在海拔梯度的空间序列上都与温度变化存在较好的相关关系；泥炭地附近获得的树轮样芯,其α-纤维素碳同位素与6-8月的平均温度存在显著的正相关关系。结合对全球其它研究地点相关现代过程研究结果的分析、与国内其它典型泥炭纤维素碳同位素记录、中亚干旱区典型湿度记录以及可靠的温度记录的对比分析,我们认为阿勒泰泥炭纤维素碳同位素应该是一个温度变化的指示器。因此,阿勒泰泥炭纤维素碳同位素主要记录了该区域过去11.5 ka以来温度的演化历史,其温度变化表现出早、晚全新世温度相对较高而中全新世相对较低的“V”型特征,且温度变化整体上可以分为4个阶段：约11.4～9.9 ka BP为低温期；约9.9～6.2 ka BP为高温期,但也存在一些明显的冷事件的波动：约6.2～3.9 ka BP为相对低温期；约3.9-0 ka BP为相对高温期。进一步的驱动机制分析结果表明：在轨道尺度上,该泥炭纤维素碳同位素记录的温度变化主要受控于太阳辐射和温室气体含量变化。具体表现在,早全新世的高温期主要受太阳辐射的驱动,而晚全新世的升温趋势可能与大气温室气体含量增加有关；在千年尺度上,阿勒泰泥炭纤维素碳同位素清晰的记录了数次明显的气候突变事件,与北大西洋浮冰碎屑事件有较好的对应关系,说明北大西洋的温度变化通过西风环流对中亚干旱区的温度具有一定影响；功率谱分析和突变事件的对比分析表明,研究地点11.5 kaBP以来的温度长期变化趋势上还叠加了百年尺度上的太阳活动的影响。泥炭纤维素稳定同位素的气候环境指示意义复杂,相关的现代过程研究对于明确某一具体研究点泥炭纤维素稳定同位素的气候环境意义具有重要的参照意义。我们的初步结果表明,阿勒泰泥炭纤维素碳同位素具有高分辨率重建全新世温度变化的潜力,这对于深入理解该区域全新世以来气候演化和可能的气候驱动机制都具有重要的科学意义。
[Abstract]:In the ARL Taishan Hara sand wetland, a peat core with a length of 742cm was collected by peat hand drill. A large amount of conditional experiments were carried out with reference to the extraction process of the domestic and foreign trees, lakes and peat - alpha cellulose. Finally, a set of effective process for the extraction of alpha cellulose suitable for peat core samples was established. The cellulose extraction and stable carbon isotope analysis of the peat core samples obtained from the Taishan Hara sand wetland, Northern Xinjiang, were tested by the vitamin extraction process to establish its evolution sequence since the past 11.5ka. In order to clarify the climatic and environmental significance of the carbon isotopes of Aletai peat cellulose, we were 4-9 in 2014. Modern process studies were carried out in the peat area, including monthly precipitation, peat soil water, stream samples and collection of sedge samples each month in peat, and sample of sedge at 2000-2450m elevation; 23 other modern plant samples were collected in peat land in July, and 4 sib at about 2000m altitude in August. 12 tree core of Leah larch. Cellulose extraction and stable carbon isotope analysis of collected SHAKESPEA, modern plant samples and tree wheel samples. Modern process research in peat land in Aletai showed that the dominant plant of the peat was sedge, and its cellulose carbon isotopes were in time. There is a good correlation between the spatial sequence and the spatial sequence on the elevation gradient. The tree core in the vicinity of the peat land has a significant positive correlation with the average temperature of 6-8 months. Other typical peat cellulose carbon isotopes, typical humidity records in the arid region of Central Asia and a reliable temperature record comparison, we believe that the carbon isotopes of Aletai's Peat cellulose should be an indicator of temperature changes. Therefore, the carbon isotopes of Aletai peat cellulose mainly recorded the past 11.5 Ka of the region. The temperature evolution history shows that the temperature changes show early, late Holocene and lower middle Holocene "V" type characteristics, and the temperature change can be divided into 4 stages on the whole: About 11.4 to 9.9 Ka BP as cryogenic period; about 9.9 to 6.2 Ka BP as high temperature period, but there are some obvious fluctuations of cold events: about 6.2 to 3. .9 Ka BP is relative low temperature period; about 3.9-0 Ka BP is a relatively high temperature period. Further driving mechanism analysis shows that the temperature change of the carbon isotope record of the peat cellulose is mainly controlled by the change of solar radiation and greenhouse gas content on the track scale. The warming trend of the late Holocene may be related to the increase of atmospheric greenhouse gas content. On the Millennium scale, the carbon isotopes of Aletai peat cellulose clearly record several obvious climatic catastrophes, which have a good correspondence with the North Atlantic ice debris events, indicating that the North Atlantic temperature changes through the westerly circulation. The temperature of the arid region of Central Asia has a certain influence. The analysis of power spectrum analysis and the comparison of the catastrophe events show that the long-term change trend of the temperature since the 11.5 kaBP is also superimposed on the influence of the solar activity on the Centennial scale. The climate ring indication of the stable isotopes of peat cellulose is complex, and the related modern process research Our preliminary results show that the carbon isotopes of Aletai peat cellulose have the potential to reconstruct the Holocene temperature with high resolution, which is useful for the understanding of the climate evolution since the Holocene in this region. The climate driving mechanism of energy has important scientific significance.

【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P597;P532

【参考文献】