| 摘要: |
| 湖泊沉积物的磁性参数是古气候、古环境的重要代用指标。通过对青海湖QI5孔和岱海DH32孔短岩心的磁化率、频率磁化率的研究,并与地球化学参数等其它资料对比,探讨了以上两个湖区历史时期古气候变化规律;论证了用磁化率、频率磁化率作为古气候、古环境指标的可靠性和敏感性;并对其变化机制进行了初步探讨。 |
| 关键词: 湖泊沉积物 磁化率 频率磁化率 气候变化 |
| DOI：10.18307/1993.0204 |
| 分类号: |
| 基金项目:国家自然科学基金(48701330)和中日合作青海湖研究课题 |
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| MAGNETIC SUSCEPTIBILITY (X) AND FREQUENCY DEPENDENT SUSCEPTIBILITY (Xfd) OF LAKE SEDIMENTS AND THEIR PALEOCLIMATIC IMPLICATION—The case of recent sediments of Qinghai Lake and Daihai Lake |
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Wu Ruijin
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Nanjing Institute of Geography and Limnology, Academia Sinica, Nanjing 210008
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| Abstract: |
| Mineral magnetic measurement can contribute to lake sediment studies in a wide variety of ways,ranging from analysis of sediment sources to understanding of the response of lake sediments to climate change.The magnetic susceptibility (X) and the frequency dependent susceptibility (Xfd) curves of two short sediment cores from Qinghai Lake (QL5) and Daihai Lake (DH32). spanning respectively the last 500 and 300 years,have been made. It is interesting that the variations in Xfd(%) approximately coincide with those of geochemical and grain size analysis data. Additionally,due to the variation of magnetic mineral content >type and magnetic grain size controlled mainly by the processes of weathering, pedogenesis,erosion and so on,the curves (especially Xfd (%) curves) have all shown considerable regular alternations of wave peaks and troughs, implying climatic fluctuations in different time scales during historical period in the two areas. These results indicate that the magnetic parameters of lake sediments,especially their frequency dependent susceptibility are sensitive to paleoclimatic fluctuation and can provide us important information about climate change. |
| Key words: Lake sediments magnetic susceptibility frequency dependent susceptibility climate change |
