东北太平洋中国合同区悬浮颗粒物元素地球化学

CHARACTERISTICS OF THE ELEMENT GEOCHEMISTRY OF THE SUSPENDED MATTER IN THE CHINESE CONTRACT AREA,NORTHEAST PACIFIC OCEAN

利用ICP-MS对东北太平洋中国合同区3个测站分层采集的悬浮颗粒物的元素组成进行了测试,对Na、Mg、Al、Ca、Ti、Mn、Fe、Co、Cu、Sr、Ba和Pb等12种元素的含量分布及其地球化学特征进行了研究和对比。结果表明,水体中悬浮体总量(TSM)一般低于0.3mg/dm3,12种元素含量从几百到不足0.01μg/dm3。其分布以500和5000m为界可分为3层。元素中Al和Ti可作为陆源元素指标,Sr和Ba可作为生源元素指标,Pb主要来源于人类活动。在西区,Na、Mg和Ca主要为生源元素,Mn、Fe、Co和Cu主要为陆源元素。在东区,Na、Mg和Cu为多源元素,Ca、Mn、Fe和Co以陆源为主。颗粒物物源及供应量是颗粒物和元素含量分布的控制因素。西小区海底火山活动强烈是影响两区元素组分差异的直接因素之一。

The elemental components of the suspended matter samples collected from different layers in the water column at 3 stations in the Chinese Contract Area, Northeast Pacific Ocean, were analyzed by ICPMS. The content of the 12 elements （including Na, Mg, Al, Ca, Ti, Mn, Fe, Co, Cu, Sr, Ba and Pb） of the suspended matter ranges from several hundreds to less than 0.01 μg/ dm3 as the content of total suspended matter （TSM） in the water column was less than 0.30 mg/din3 in general. The concentrations of suspended matter and the 12 elements in the upper layer of 500 m are higher than that in the mediate layer from 500 to 5 000 m of the water depth with minor fluctuations. However, sharp fluctuation of the concen- trations of the suspended matter and 12 elements was found in the lower layer 〉5 000 m of the water depth in the water column. Among the 12 elements, Al and Ti mainly originated from terrigenous particles; Sr and Ba mainly originated from marine autogenic particles and Pb was mainly related with anthropic activi- ty, respectively, resulting from their geochemical characteristics. According to correlation analysis of the 12 elements, Na, Mg and Ca mainly originated from marine autogenic particles,similar to Sr and Bio-Ba; otherwise, Mn, Fe, Co and Cu mostly came from terrigenous particles in the western part. In the eastern part, the concentration of Na, Mg and Cu showed multi-sources characteristics, while the sources of Ca, Mn, Fe and Co were the same as those of A1 and Ti. The materials source and its amount of supply were the controlling factors for the concentration and distribution of the TSM and its element compositions in the water column at different stations. Relatively abundant supply of volcanic matter, caused by relatively strong seafloor volcanic eruption in the western part of study area,was a direct factor to conduce to the diverse distribution of the same elements at different stations.