三峡中坝遗址剖面中汞的地球化学特征和影响因素分析

长江三峡中坝遗址是我国目前仅有、世界上也罕见的"通史式"遗址。它不仅蕴藏着大量的文化内涵,而且包含着极其丰富的自然环境演变信息。我们对遗址剖面地层中汞的含量和垂直分布变化进行了测试和分析,发现该剖面地层中汞含量高,这与遗址沉积物中硫含量高、复杂的区域地质构造条件以及频繁的人类活动有关。同时发现,汞含量在地层中呈垂直波动变化,这反映了该地区人类生产活动、气候条件、植被状况和剖面沉积物粒度大小等的影响,即与该地区人类活动以及自然环境演变有相当关系。遗址剖面中汞的含量变化在一定程度上记录了该地区人类活动的进程和自然环境的演变。

DISTRIBUTION CHARACTERISTICS OF Hg CONCENTRATIONS IN STRATA AT ZHONGBA SITE PROFILE AND ANALYSIS OF INFLUENTIAL FACTORS

The Zhongba site of the Three Gorges is only a "generally historic" site in China at present, uncommon in the world. There is an unabridged and complete stratigraphic sequence profile at the Zhongba site. This profile contains not only quite a number of culture messages, but also a lot of information about environmental evolution. Based on environment archeology at the Three Gorges Zhongba site, this paper analyses the distribution characteristics of Hg in Quaternary sediments and influential factors. High contents of Hg may be ascribed to high S contents, complex regionally geological structure and frequent human activities. The vertical variation of Hg contents in the relic site strata are related to the regional human activities, climate conditions, vegetation status and sediment grain size, namely the regional natural environment evolution. This work sheds a light on natural environmental changes and human activity processes in the Three Gorges region of the Yangtze River.