Journal of Marine Sciences ›› 2021, Vol. 39 ›› Issue (2): 12-20.DOI: 10.3969/j.issn.1001-909X.2021.02.002

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Sedimentary characteristics and environmental significance since the last glaciation recorded in core E20 in the western Pacific Ocean

LI Yue1,3,4, XU Dong*2,3, ZHANG Zhiyi3, JIANG Kedi1,4, LIU Geng3   

  1. 1.Key Laboratory of Coast and Island Development, the Ministry of Education, Nanjing University, Nanjing 210046, China; 
    2.Key Laboratory of Submarine Geosciences, Ministry of Natural Resources, Hangzhou 310012, China; 
    3.Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China; 
    4.School of Geography and Ocean Science，Nanjing University, Nanjing 210046, China
  • Online:2021-06-15 Published:2021-06-15

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Abstract: Diatom mat deposits have been discovered in the tropical western Pacific successively, and its formation time and mechanism are of great significance for the study of carbon cycle in the tropical western Pacific. In this study, high-resolution XRF element scanning, color scanning and AMS14C dating analysis were performed on sediment of core E20, which contains nearly 2.5 meters of diatom mat deposit in the west Mariana Arc. The results showed that the core E20 could be divided into three sedimentary units, those were clay, siliceous ooze, siliceous clay from bottom to top, and elements Ti, Fe, Cu, Br, etc. showed three-stage change, Ca and Si showed reverse change. Based on 14C-AMS ages, E20 reflected the significant environmental changes in the western Pacific since the last glaciation, the bloom time of diatom mats was from 10.9 ka B.P. to 28.6 ka B.P., and the increase of dust input during the last glaciation should be the main reason for the diatom bloom in the oligotrophic tropical western Pacific. Local low-lying topography was conducive to the preservation of diatom mats.

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