标题：The Geochemistry and Bioturbation of Clay Sediments Associated with Amalgamated Crusts at the Gagua Ridge
作者：Chen, Shuai; Zeng, Zhigang; Wang, Xiaoyuan; Yin, Xuebo; Zhu, Bowen; Guo, Kun; Huang, Xin
作者机构：[Chen, Shuai; Zeng, Zhigang; Wang, Xiaoyuan; Yin, Xuebo; Zhu, Bowen] Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, S 更多
通讯作者：Chen, S;Wang, XY;Chen, S;Wang, XY;Chen, S;Wang, XY
通讯作者地址：[Chen, S; Wang, XY]Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Shandong, Peoples R China;[Chen, S; Wang, XY]Qingda 更多
关键词：Gagua Ridge; amalgamated crusts; clay sediments; eolian dust;; bioturbation
摘要：Based on the analysis of geochemical and mineralogical compositions, deep sea clay sediment characteristics and their material sources were examined in the eastern flank of the Gagua Ridge. The mineralogy mainly consists of detrital clay minerals, quartz, and authigenic phillipsite. There is scarce biogenic debris (siliceous or calcareous). The consolidated sediments are more enriched in Si, Al, K, Na, Li, Sc, Cr, Rb, and Cs than the associated crusts and nodules. The unmixed sediment samples were mainlycontributed by Asian eolian dust. The onset of the outer Fe-Mn crust growth nearly coincides with the Central Asia aridification event at similar to 3.5 Ma, which resulted in an abrupt increase in eolian flux of Asian dust. Intensified surface primary productivity is assumed to bring more metals to deep waters, and eventually facilitate the outer Fe-Mn crust formation. Authigenic phillipsite may come from the alteration of local basic volcanic glasses and cause excess Al, high Al/Ti, and low Si/Al ratios. However, phillipsites hardly affect the abundance of rare earth elements (REEs) and their patterns. In addition, the investigation of two kinds of burrows inside the consolidated sediments reveals that the inner nodules of the amalgamated crusts may remain on the oxic sediment surface, due to frequent benthic activities.