东海岛屿风尘堆积的物源示踪研究

Eolian deposition located on the Islands of East China Sea record the abundant environmental information. The past reports showed that the eolian deposition of the Islands of East China Sea accumulated in the Late Quaternary, but, the researchers are still locked in disagreement over proposals to material sources of Eolian deposition located on the Islands of East China Sea. In this proposal we try to choose Langgangshan Island, Shengshan Island, and Feishaao of Mountain Putuo as the study objects, compare sediment source characteristics in different depositional stages of the Islands of East China Sea and source regions by properties of geochemistry, physics, mineralogy and paleontology, which are based on the results supported previous research foundation. By this research we would achieve the purpose as following: 1) build a material sources identification system of the Islands of East China Sea; 2) reveal the relationship between the Quaternary environmental evolution of the Islands of East China Sea and the global paleoclimate and paleoenvironment; 3) explore the temporal and spatial variation characteristics of natural sources of atmospheric particulates on the the Yangtze river delta regions.

分布在我国东海岛屿的风尘堆积记录着丰富的环境变化信息。已有的研究表明东海岛屿风尘堆积堆积于第四纪晚期，但关于中国东海岛屿黄土的物源还存在分歧。本课题在前期研究的基础上，以浪岗山岛、嵊山岛、普陀山飞沙岙的风尘堆积为研究对象，综合运用地球化学、物理学、矿物学和古生物学指标，比较东海岛屿和源区的沉积物在不同沉积阶段的物源特征，建立东海岛屿风尘堆积的物源识别体系，揭示中国东部海域第四纪环境演变与全球古气候、古环境之间的关系；探索长江三角洲地区大气颗粒物自然来源时空变化特征。

黄土-古土壤序列是古环境和古气候信息的重要载体，对其深入研究有助于理解第四纪以来我国乃至全球的气候变化历史。嵊山岛位于我国东部沿海，地处海陆交汇带，其自然地理环境受东亚季风控制。本工作以嵊山岛黄土为研究对象，基于光释光、电子自旋共振测年等方法建立的年代标尺，通过沉积学、环境磁学、元素地球化学和有机碳同位素等方面的测试与分析，并结合气候模型UVic_ECSM的区域植被覆盖敏感性模拟研究，重建了末次冰期以来东部古气候演化历史，为第四纪时期气候变化研究提供科学数据和理论依据。取得的初步结论主要如下：（1）构建东海岛屿风尘沉积地层的年代框架；（2）建立东部黄土粒度分析测试方法；（3）揭示了东海岛屿风尘堆积和南方红土磁性增强机制；（4）定量计算结果显示，晚末次冰期以来区域沉积环境以C3型植被发育为主。