山东半岛北岸跨锋面物质输运对辽东半岛东岸沉积有机质含量及来源的影响

The influence of cross-front sediment transport in north coast of Shandong Peninsula on the content and origin of sedimentary organic matter in east coast of Liaodong Peninsula

中文关键词:  跨锋面物质输运  东亚冬季风  黄海暖流  沉积有机质  山东半岛北岸  辽东半岛东岸

英文关键词:cross-front sediment transport  East Asian Winter Monsoon  Huanghai Sea Warm Current  sedimentary organic matter  north coast of Shandong Peninsula  east coast of Liaodong Peninsula

中文摘要:

      深入理解气候变化影响下海洋动力过程变化其多重环境效应，是了解海岸海洋系统未来演化趋势的重要途径。因此，本文在辽东半岛东岸泥质区取柱状样一根，通过沉积物粒度、TOC/TN 含量、 13C 以及15N 等指标，分析气候变化下山东半岛北岸跨锋面物质输运强度变化，及其对辽东半岛东岸泥质区沉积有机质含量和来源的影响。结果表明，高海面时期以来，山东半岛北岸跨锋面物质输运可分为两个变化阶段：6.5~2.9 cal ka BP，其强度随冬季风和黄海暖流的不断减弱而减弱； 2.9 cal ka BP 至今，由于冬季风较弱而黄海暖流总体强盛，其强度随黄海暖流的波动而呈现 4 段式的复杂变化。此外，辽东半岛东岸泥质区陆源和海源有机质含量与其强度呈正相关，相应于跨锋面物质输运强度的变化，6.5~2.9 cal ka BP 期间，陆源和海源有机质含量持续减少，而 2.9 cal ka BP 至今则呈现复杂的 4 段式变化。总体上看，自 6.5 cal ka BP 以来，陆源有机质贡献率不断下降而海源有机质贡献率逐渐上升。

英文摘要:

      An in-depth understanding of variations in ocean dynamics induced by climate change and its multiple effects on the environment is an important approach to gain insights into the future evolution trend of coastal ocean system. In order to study the fluctuation of cross-front sediment transport intensity in north coast of Shandong Peninsula under climate change and its influence on content and origin of sedimentary organic matter in Liaonan Coastal Mud, a sediment core in Liaonan Coastal Mud was collected and then analyzed with proxies including sediment grain size, TOC and TN content, 13C and 15N. The results indicate that cross-front sediment transport in north coast of Shandong Peninsula could be divided into 2 changing stages since the sea level reaching its maximum. From 6.5~2.9 cal ka BP, its intensity decreased continuously with the gradual weakening of winter monsoon and Huanghai Sea Warm Current. Since 2.9 cal ka BP, due to the weaker winter monsoon and the overall stronger Huanghai Sea Warm Current, its intensity fluctuated for 4 different sub-stages along with the fluctuation of Huanghai Sea Warm Current. Besides, the content of terrigenous and marine organic matter in Liaonan Coastal Mud showed a positive correlation with cross-front sediment transport intensity. Corresponding to its changes, the content of terrigenous and marine organic matter decreased persistently during the period of 6.5~2.9 cal ka BP, and then exhibited 4 complicated changing sub-stages from 2.9 cal ka BP to present. In general, the proportion of terrigenous organic matter in total organic matter has been declining while the marine organic matter's proportion has been rising since 6.5 cal ka BP.