海南岛双池玛珥湖全新世磁化率及其环境意义

Holocene Magnetic Susceptibility from Shuangchi Maar Lake,Hainan Island and Its Environmental Significance

海南岛双池玛珥湖沉积物磁化率高分辨率的时间序列分析表明，磁化率与粒度指标和粘土矿物含量存在相关关系，磁化率突变往往对应于沉积物的突变界面，因此与沉积相变化可以对比。磁化率与碳、氮含量呈负相关。表明湖泊的有机质生产力高时磁化率较低。多指标的对比分析进一步证明了中国热带全新世高温期为：7200～2700aBP，高温期从炎热而降雨量相对低的稳定时期过渡到频繁变动的气候不稳定阶段；晚全新世，尤其在2700aBP左右，气候模式发生了重大转折，波动幅度变大，可能与厄尔尼诺-南方涛动（ENSO）活动性增强有关。海南岛热带玛珥湖磁化率对短尺度气候变化的响应是敏感的，磁化率的高值主要反映了降雨增强，同时也能叠加降温信号。

The analysis of the high-resolution time series of magnetic susceptibility （X） reveals thatX value is correlative to the index of grain size, as well as to the content of clay mineral. Abrupt changes observed in the sedimentary phases can be generally reflected by X value. It is then suggested that the changes in X value is feasible and significant to indicate the sedimentation alternations. Additionally, the observed result shows that X has negative correlation with the percentages of total organic carbon and nitrogen respectively, indicating a high productivity of organic matter in the Maar lake when X is low. The muhidisciplinary results demonstrate that the Thermal Maximum in the Holocene lasted from 7200 to 2700 aBP, which was characterized by the transition from a climate pattern of stabilization, torridity and low precipitation initially to a climate system of high variability latterly. In the Late Holocene, especially at 2700 aBP, a distinct environmental change with the considerable amplitude of variation indicating an important climate transition in the tropical eastern Asia was recorded, probably responding to the enhancement of ENSO phenomena in the Pacific Ocean. In addition, it is testified that X was sensitive in recording the rapid climate changes in the Holocene, and that as an indicator of great precipitation, high X sometimes implies a decrease of temperature.