7.8 kaBP以来海南岛东南陆架陆源碎屑来源及其环境响应

对取自海南岛东南部的X2站柱状样品进行了粒度、全岩稀土元素和重矿物分析，探讨了7.8 kaBP以来海南岛东南陆架陆源碎屑来源及其环境响应。粒度端元模拟识别出了两个端元，EM1端元对应的是海洋流系搬运的近源与远源细粒物质的混合沉积，EM2对应的主要是近源海南岛河流输入的粗粒物质，两个端元代表着两个不同的输运机制。物源分析结果表明，7.8 kaBP以来X2站陆源碎屑来源较为稳定，主要来源于海南岛。4 kaBP以来，X2站粒度、稀土元素和重矿物特征参数发生了显著改变，与El Nino-Southern Oscillation (ENSO)事件开始增强有很好的对应关系，推测频繁的ENSO事件导致降雨量增加是研究区风化程度增强的主要原因。与全岩稀土元素特征指标相比，X2站重矿物组合受源区风化剥蚀的影响更为显著，后期在环境演化研究中，应适当关注重矿物这一指标。

Provenance and environmental response of terrigenous debris in the southeastern continental shelf of Hainan Island since 7.8 kaBP

Grain-size, bulk Rare Earth Element (REE), and heavy mineral analysis of Core X2 at southeastern Hainan Island were carried out. The provenances of terrigenous clasts and their environmental responses of this study area since 7.8 kaBP were discussed. Two endmembers were identified by grain-size endmember simulation. The EM1 endmember corresponded to the fine-grained material transported by the ocean current system, while the EM2 endmember corresponded to the coarse-grained material input from nearby rivers in Hainan Island; therefore, the two endmembers represented two different transport mechanisms. Results show that since 7.8 kaBP, the provenance of terrigenous detrital of Core X2 was relatively stable, mainly from Hainan Island. After 4 kaBP, the grain size, REE, and heavy mineral characteristic parameters of Core X2 had changed significantly, which has a good correspondence to the intensification of El Nino and Southern Oscillation (ENSO). It is speculated that the increase of rainfall caused by frequent ENSO events is the main reason for the enhancement of weathering degree in the study area. Compared with the characteristics of REE, the heavy mineral assemblages of Core X2 were more significantly affected by weathering and denudation in the source area. Therefore, study on heavy mineral index is suggested in the future study of environmental evolution.