泉州湾海岸带全新世地层及沉积环境演化

EVOLUTION OF HOLOCENE STRATIGRAPHY AND SEDIMENTARY ENVIRONMENT IN QUANZHOU BAY COAST

海岸带地层及沉积环境演化研究对于认识海陆相互作用及预测未来环境演变具有重要意义。基于福建省泉州湾南岸钻孔DZ02全新世地层岩性特征、AMS-14C测年及粒度、有孔虫、介形类等环境代用指标综合分析,本文建立了该钻孔的全新世地层年代框架,并结合前人的研究成果,探讨了该区全新世沉积环境的演化过程。结果表明:泉州湾海岸带全新世沉积环境经历了早期的河口湾、中期的陆架浅海、晚期的河口湾及冲积平原演化过程,形成了一次完整的海侵-海退过程,即前人研究命名的“长乐海进”,其极盛期发生在中全新世中后期7—4 ka。

The coastal zone is a sensitive area for land-sea interaction and records rich information on changes in sedimentary environment. It is of great significance to study the evolution of regional stratigraphy and sedimentary environment by studying coastal sediments, for understanding the interaction between sea and land and predicting future environmental evolution. Based on the stratigraphic lithology and sedimentary characteristics of hole DZ02 on the south bank of Quanzhou Bay, Fujian Province, AMS-14C dating method was used to establish reliable chronostratigraphy. Comprehensive sedimentary facies analysis was carried out using environmental proxy indicators such as grain size and micro paleontology. Combined with the previous research results, the process of Holocene sedimentary environment evolution was reconstructed in this area. The results show that, Holocene sedimentary environment of Quanzhou Bay coastal zone experienced the evolution process of the estuary bay in Early Holocene, the shelf-shallow sea in Middle Holocene, and the estuary bay and alluvial plain in Late Holocene. A complete transgression-regression process was formed in this area in Holocene, which is named “Chang Le transgression” by previous studies. The maximum of the transgression occurred at about 7-4 ka in Middle Holocene.