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.
LI Yue, XU Dong, ZHANG Zhiyi, JIANG Kedi, LIU Geng
. Sedimentary characteristics and environmental significance since the last glaciation recorded in core E20 in the western Pacific Ocean[J]. Journal of Marine Sciences, 2021
, 39(2)
: 12
-20
.
DOI: 10.3969/j.issn.1001-909X.2021.02.002
