泥炭的腐殖化度与全新世气候环境

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	泥炭的腐殖化度与全新世气候环境
其他题名	The Peat Humification in Palaeoclimatical Research
	王华
	2003
学位授予单位	中国科学院地球化学研究所
学位授予地点	中国科学院地球化学研究所
学位名称	博士
学位专业	地球化学
关键词	泥炭腐殖化度古气候全新世印度西南季风西太平洋副热带高压
摘要	泥炭是第四纪，特别是全新世以来的产物。它的形成和积累主要受控于气候，其次是地质、地貌、水文等因素。因此，泥炭形成过程中包含了大量的古气候、古环境演化信息。腐殖化度在国外早已用于古气候研究，国外学者将它作为湿度代用指标，用以恢复古湿度变迁。本文首次将之引入我国泥炭古气候研究，同时结合青藏高原的气候特点，及泥炭形成过程中温度、湿度对它的影响，赋予了泥炭腐殖化度新的气候内涵。即泥炭的腐殖化度高，指示气候温暖湿润；泥炭的腐殖化度低，指示气候干燥寒冷。本文通过对青藏高原东北部红原泥炭的腐殖化度研究，并与其它研究成果对比，得出如下结论：（1）红原泥炭腐殖化度记录了过去12000年以来当地气候干湿冷暖的变化。其气候变化大致可分为3个阶段：11.8-11.2 kaBP，气候干燥寒冷；11.2-5.5 ka BP，气候温暖湿润；5.5-0 ka BP，当地气候由早中全新世温暖湿润的气候向干燥寒冷的气候波动。红原泥炭腐殖化度记录的气候变化与高原青海湖沉积物、松西错沉积物、敦德冰芯、古里雅冰芯记录的气候变化相似，表明青藏高原12000年以来可能受同一气候系统影响，其气候变化的共同特点为干冷与暖湿交替。（2）泥炭腐殖化度记录了12000年以来印度西南季风在高原的强弱演化。新仙女木期（11.8-11.2kaBP），季风强度最弱；从11.2kaBP到10.8kaBP季风强度快速增强；在10.8ka即到5.5 ka BP，季风强度一直处于强势阶段；从5.5 ka BP开始，印度西南季风强度逐渐减弱，这期间腐殖化度同时记录了百年一千年尺度印度西南季风增强事件，但总体减弱的趋势不变。（3）泥炭腐殖化度记录的百年一千年气候突然变化事件与北大西洋浮冰事件存在遥相关。对应8次浮冰事件，红原地区气候同时变得干冷，而印度西南季风强度也减弱，这表明不但末次冰期印度西南季风与北大西洋气候密切相关，而且在全新世，这种相关性同样存在。（4）泥炭腐殖化度距平值较好的反映了西太平洋副热带高压近5000年来的活动变化。腐殖化度代用指标能很好地记录较长时间西太平洋副热带高压的变化，而对西太平洋副热带高压数十年到百年的频繁波动，则记录不明显。（5）泥炭腐殖化度时间序列的功率谱分析表明，太阳活动对红原地区气．候演化有重要影响，同时太阳活动通过影响全球水循环，进而驱动温盐环流的变化，进一步影响全球气候变化。（6）泥炭腐殖化度能同时记录温度、湿度的变化，并且测定方法简便、快捷，值得进一步研究。
其他摘要	Peat deposition is normally formed in the Quaternary, especially in the Holocene. Since the formation of peat is mainly controlled by the climate condition, peat deposition contains a lot of the palaeoclimatical and palaeoenvironmental information. Peat humification has been used as a proxy indicator for humidity in palaeoclimatical study in abroad. However it has not yet been used in China so far. In this research work based on the climate character of the Qinghai-Xizang Plateau we study on the influences of both temperature and humidity on the formation of the Hongyuan peat bog. We have revealed for the first time new climate significance of peat humification, which is that higher peat humification may indicate both more warm and more humid climate condition. In contract, lower peat humification may reflect both more dryer and more colder condition. Through the comparison between peat humification and other climate proxy indicators we have obtained the several conclusions as following: (1) Peat humification has better recorded the climate variations during the last 12000 years in Hongyuan region. In the periods from around 11800 to 11200 a BP and from around 11200 to 5500 a BP, the local climate are dry-cold and warm-humid respectively. From around 5500 a BP onward the climate turns to dry-cold again. The climate conditions inferred from the Hongyuan peat humification record are similar to once inferred from the records of Qinghai lake deposit, Songxi Co deposit, Dunde ice core, and Guliya ice core, which shows that during the last 12000 years the Qinghai-Xizang Plateau is controlled by a same climate system and the general characters of the climate are that the dry-cold alternates with the warm-humid climate condition. (2) Peat humification has recorded the variation of the Indian Ocean summer monsoon in the Hongyuan region over the last 12000 years. During the period from around 11200 to 11800 a BP corresponding to the Younger Dryas, the peat humification is lowest, indicating lowest relative humidity and temperature in the Hongyuan site, which can be attributed to the weakest summer monsoon activity. From around 11200 to 10800 a BP, the intensity of the Indian Ocean summer monsoon is rapidly increase, and keep on strengthing to around 5500 a BP. From around 5500 a BP onwards, the strength of the monsoon tends to gradually decrease in the Hongyuan site. There are abruptly increase the intensity Indian Ocean summer monsoon on the centennial to millennial time scales, but the whole decline trend don't change. (3) Peat humification recorded a series of abrupt variations of the climate on the centennial to millennial time scales. When Hongyuan region climate become dry-cold, the intensity of Indian summer monsoon is decrease, which corresponding to each of the eight IRD events. There is a close correlation between the strength variation of the Indian Ocean summer monsoon and the climate change of the North Atlantic, which is present not only in the last glacial, but also in the entire Holocene. (4) The peat humification has been used for indicating the subtropical high activities of the Western Pacific Ocean during the last 5000 years. Humification proxy has better recorded the subtropical high activities of the Western Pacific Ocean for long period. For shorter period(decadal to centennial years), the humification proxy is less sensitive. Power spectrum analysis indicates that solar activity seems to have important influence on the climate change in Hongyuan region. Solar variability influences the globe water circulation, then drive the change of the thermohaline circulation, and further influence globe climate shift. (6) The peat humification can record not only temperature but also humidity. And the method is more simple, so the peat humification should further study.
页数	93
语种	中文
文献类型	学位论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/3666
专题	研究生_研究生_学位论文
推荐引用方式 GB/T 7714	王华. 泥炭的腐殖化度与全新世气候环境[D]. 中国科学院地球化学研究所. 中国科学院地球化学研究所,2003.

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