林刚, 陈琳莹, 罗敏, 陈多福. 西太平洋新不列颠海沟表层沉积物的地球化学特征及其物源指示[J]. 海洋地质与第四纪地质, 2019, 39(3): 12-27. DOI: 10.16562/j.cnki.0256-1492.2018060701
引用本文: 林刚, 陈琳莹, 罗敏, 陈多福. 西太平洋新不列颠海沟表层沉积物的地球化学特征及其物源指示[J]. 海洋地质与第四纪地质, 2019, 39(3): 12-27. DOI: 10.16562/j.cnki.0256-1492.2018060701
LIN Gang, CHEN Linying, LUO Min, CHEN Duofu. The geochemical characteristics of the surface sediments in the New Britain Trench of the Western Pacific Ocean and their implications for provenance[J]. Marine Geology & Quaternary Geology, 2019, 39(3): 12-27. DOI: 10.16562/j.cnki.0256-1492.2018060701
Citation: LIN Gang, CHEN Linying, LUO Min, CHEN Duofu. The geochemical characteristics of the surface sediments in the New Britain Trench of the Western Pacific Ocean and their implications for provenance[J]. Marine Geology & Quaternary Geology, 2019, 39(3): 12-27. DOI: 10.16562/j.cnki.0256-1492.2018060701

西太平洋新不列颠海沟表层沉积物的地球化学特征及其物源指示

The geochemical characteristics of the surface sediments in the New Britain Trench of the Western Pacific Ocean and their implications for provenance

  • 摘要: 海沟通常拥有全球最深的区域——深渊,由于地理位置、地形地貌和气候等差异,海沟沉积物可能有不同的物质来源。因此,为进一步了解海沟深渊区的物质组成与来源,选取近陆的新不列颠海沟作为研究对象,通过分析其海底表层沉积物的地球化学特征,追踪新不列颠海沟不同水深与区域的沉积物来源。研究发现不论位于半深海、深海,乃至深渊区域,新不列颠“八字型”海沟的表层沉积物主要来自于周边岛屿的火山物质,但“八字型”海沟的西支和东支有差异,西支主要为新不列颠岛东部Rabaul火山和北部火山群及所罗门群岛的火山物质,其中在西支的最北站位新不列颠岛北部火山物质的比例最高。与西支相比,东支还受到了更多来源于TLTF(Tabar、Lihir、Tanga和Feni火山)火山链物质的影响,海沟东西支物源的差异与该地区复杂的洋流密切相关。此外,西支海沟轴部(最底端)站位更多来源于岛屿河流沉积物,受火山物质影响相对较小。

     

    Abstract: Most of the world trenches belongs to the hadal zone, the deepest part of the earth. The sources of sediments in the trenches are always different due to the difference in geographic location, topography, climate and others. In order to further understand the composition and sources of sediments in hadal trenches, the New British Trench, which is close to land, is chosen as the research object of this paper. By analyzing the geochemical characteristics of the bottom sediments of the trench, we studied the sources of sediments in different depths and regions of the trench. It is found that the bottom sediments of the New Britain Trench shaped like a reversed V are mainly derived from the surrounding volcanogenic materials, no matter they are located in the bathyal zone, abyssal zone, or even hadal zone. However, the materials in the western part of the reversed V shaped trench are rather different from those in its east. The western part of the New British Trench is mainly affected by volcanogenic materials from the Rabaul Volcano in the east of the New Britain Island, the northern part volcanoes of the New Britain Island, and the Solomon Islands, and the proportion of volcanogenic materials is the highest in the northeast stations from the northern part volcanoes of the New Britain Island. Compared to the western part, the eastern part of the New British Trench is more strongly affected by the TLTF volcanic chain (volcanoes Tabar-Lihir-Tanga-Feni). It is believed that the different sources of the New British Trench are related to the complex ocean currents between the western part and the eastern part of the trench. Furthermore, the bottom (the deepest) of the western part of the trench is dominated by river sediments but less influenced by volcanogenic materials.

     

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