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底栖有孔虫群落及其地球化学组成是海底冷泉区发育的重要指示标志之一。对南海北部东沙西南海域4个含碳酸盐结核表层沉积物样品进行了底栖有孔虫群落分析,以探讨该区底栖有孔虫对冷泉活动的响应特征。结果表明,该区底栖有孔虫群落组合总体具有玻璃壳含量高、胶结壳含量低的特征,主要属种以Cibicides pseudoungerianus,Globocassidulina subglobosa为主,其次Discanomalina semipunctata,Gyroidina soldani,Lenticulina orbicularis和Cibicides lobatulus也有较高含量。该区底栖有孔虫群落组成与邻近正常沉积区有显著差异,总体上含碳酸盐结核区底栖有孔虫以玻璃壳表生种为主,而正常沉积区的胶结壳和内生种则相对有较高含量。Cibicides属底栖有孔虫和D.semipunctata通常附生于蠕虫管壁、珊瑚枝或碳酸盐结核表面,它们在东沙西南区域大量出现可能与该区硬底质沉积密切相关。我们提出D.semipunctata可作为南海北部硬底质类型冷泉活动的指示标志。
Benthic foraminiferal community and its geochemical composition is an important indicator of the development of the seabed cold spring zone. Benthic foraminiferal communities were analyzed on four carbonate sediment-bearing sediment samples in the southwestern part of the South China Sea in the southwestern part of Dongsha to investigate the response characteristics of benthic foraminifer to cold spring activities. The results showed that the benthic foraminiferal assemblages in this area were characterized by high content of glass shells and low content of cement shells. The main species were Cibicides pseudoungerianus and Globocassidulina subglobosa, followed by Discanomalina semipunctata, Gyroidina soldani, Lenticulina orbicularis and Cibicides lobatulus There is also a higher content. The composition of benthic and foraminifer communities in this area is significantly different from that of the adjacent normal sedimentary areas. Generally, the benthic foraminifera in the carbonate-containing tuberculosis zone is dominated by the vitreous shell epiphytic species, whereas in the normal sedimentary region, The species is relatively high content. Cibicides belongs to benthic foraminifera and D. sepipunctata, which usually attach to worm’s wall, coral branches or carbonate nodules. Their abundant occurrence in the southwestern part of Dongsha may be closely related to the hard sediment deposition in this area. We propose D. semipunctata to be used as an indicator of cold hard-sink activity in the northern South China Sea.