辽东湾北部JXC-1孔孢粉组合特征及其古环境意义  

Pollen Assemblage and Its Paleo-environmental Significance of JXC-1 Borehole in Northern Liaodong Bay,Bohai Sea

作　　者：王忠蕾[1,2] 李杰 胡刚[1,2] 梅西 窦衍光[1,2] 孟祥君 WANG Zhonglei;LI Jie;HU Gang;MEI Xi;DOU Yanguang;MENG Xiangjun(Qingdao Institute of Marine Geology,China Geological Survey;Laboratory for Marine Mineral Resources,Laoshan Laboratory,Qingdao 266237,China)

机构地区：[1]青岛海洋地质研究所 [2]崂山实验室海洋矿产资源评价与探测技术功能实验室,山东青岛266237

出　　处：《广东海洋大学学报》2024年第1期93-102,共10页Journal of Guangdong Ocean University

基　　金：国家自然科学基金(42276084);中国地质调查局海洋地质调查专项(DD20230403,DD20221710,DD2023069);崂山实验室科技创新项目(LSKJ202204400)。

摘　　要：【目的】研究辽东湾北部JXC-1孔孢粉学特征,以更好地认识早更新世晚期以来辽东湾古环境演化。【方法】对JXC-1孔沉积地层选取159个样品进行孢粉鉴定,结合测年数据,对比有孔虫丰度和粒度变化等指标,开展孢粉组合及含量变化分析。【结果】划分出9个孢粉带,孢粉组合可以反映渤海陆缘区植被面貌,其中草本花粉在整个剖面占绝对优势,含量在60%以上,具有超代表性,而木本花粉代表性低。【结论】对比冰期、间冰期气候变化过程,研究区早更新世晚期以来孢粉组合变化特征指示气候呈冷干-温湿交替。中更新世末期以来辽东湾经历了3次高海平面过程,与孢粉组合指示的气候变化趋势一致,MIS7和MIS5时期,阔叶树种和蒿属比例较高,有孔虫丰度较高,气候偏暖,属沉积动力相对稳定的浅海或滨海环境;而MIS6和MIS4时期,孢粉浓度极低,气候偏冷,属沉积动力相对复杂的滨岸湖泊或沼泽等陆相环境。MIS3时期至全新世(MIS1)时期,气候由凉湿向温湿转变。全新世孢粉组合指示气温先升后降的变化趋势,与海平面变化响应明显。【Objective】In order to better understand the paleo-environment of Liaodong Bay since late Early Pleistocene,the palynology study of JXC-1 borehole was carried out.【Method】A total of 159 samples were selected from JXC-1 borehole sedimentary strata for pollen identification.Combined with the dating data,foraminifera abundance and grain size changes of the samples,pollen composition and content changes were analyzed.【Result】9 pollen zones were identified and the borehole pollen assemblages can reflect the vegetation features of the Liaodong Bay continental margin,in which the herbaceous pollen was absolutely dominant(above 60%)in the whole hole and was super representative,while the woody pollen was lowly representative.【Conclusion】Compared with the climate change process of glacial period and interglacial period,the characteristics of pollen assemblages since the late Early Pleistocene indicate that the paleoclimate in the study area alternated between cold dry and warm wet.Three transgressions have occurred in Liaodong Bay since the end of the Middle Pleistocene,which is consistent with the paleo-climate change indicated by pollen assemblages.In the MIS7 and MIS5,the proportion of broad-leaved tree species and Artemisia was relatively high,the foraminifera was also high,and the paleo-climate was warm,indicating that the study area was a shallow or coastal environment with relatively stable sedimentary dynamics.However,in the MIS6 and MIS4,the pollen concentration was very low and the paleo-climate was cold,indicating the terrestrial environment such as coastal lakes or swamps had relatively complex sedimentary dynamics.From the MIS3 to the Holocene(MIS1),the paleo-climate changed from cool and humid to warm and humid.The pollen assemblage in Holocene indicates the trend of temperature:first rising and then falling,which was obviously in response to sea level change.

关 键 词：辽东湾 晚更新世 孢粉组合 古环境 

分 类 号：P736.21[天文地球—海洋地质]