渤海湾海面变化  

Sea Level Change in Bohai Bay

作　　者：王福 胡云壮[1,2,3] 田立柱 施佩歆[1,2,3] 李建芬 陈永胜[1,2,3] 李勇 商志文[1,2,3] 姜兴钰 袁海帆[1,2,3] 杨朋 文明征[1,2,3] 赵琰琳 杨怡 王宏[1,2,3] WANG Fu;HU Yunzhuang;TIAN Lizhu;SHI Peixin;LI Jianfen;CHENYongsheng;LI Yong;SHANG Zhiwen;JIANG Xingyu;YUAN Haifan;YANGPeng;WEN Mingzheng;ZHAO Yanlin;YANG Yi;WANG Hong(Tianjin Center,China Geological Survey(North China Center for Geoscience Innovation),Tianjin 300170,China;Key Laboratory of Coast Geo-Environment,CGS,Tianjin 300170,China;Tianjin Key Laboratory for Coastal Geo-Process and Environmental Safety,Tianjin 300170,China;Hebei College of Environmental Engineering,Qinhuangdao Hebei,066102,China;Tianjin University of Urban Construction,Tianjin 300384,China)

机构地区：[1]中国地质调查局天津地质调查中心(华北地质科技创新中心),天津300170 [2]中国地质调查局海岸带地质环境重点实验室,天津300170 [3]天津市海岸带地质过程与环境安全重点实验室,天津300170 [4]河北环境工程学院,秦皇岛066102 [5]天津城建大学,天津300384

出　　处：《华北地质》2024年第1期1-20,共20页North China Geology

基　　金：国家重点基金课题:“环渤海滨海地球关键带地质结构和岩相古地理研究(42293261)”;中国地质调查局项目:“津冀沿海资源环境承载力调查(DD20189506)”;中国地质调查局项目:“黄渤海海岸带重点生态保护修复区综合地质调查(DD20211301)”;自然科学基金项目:“渤海湾全新世海面标志点研究与变化历史重建(41372173)”;“渤海湾西北岸4 ka BP前后古环境重建(41806109)”。

摘　　要：【研究目的】海面上升,是渤海湾泥质海岸带地区全新世海陆变化最主要的影响因素。通过重建海面变化历史,有助于预测今后的变化趋势。【研究方法】全球基于实际调查的建模研究,恢复了过去数万年来较高分辨率的海面变化历史、分析了导致这种变化的各类分量的贡献。我们通过地区性相对海面变化研究,着重对地区性和区域性分量或做了定量评估、或进行了半定量推理分析,并做了具体的案例研究。【研究结果】这些研究表明,距今10~7 ka时全球海面平均上升速率是~9 mm/a,同期渤海湾西岸相对海面平均上升速率是~5.6 mm/a。这一较快的上升造成了包括渤海湾在内全球沿海平原海岸线后退(以及渤海海盆-渤海湾可能的数道沿岸堤被淹没)。但是,7 ka至今,全球与冰融水等效海面(ice-equivalent sea level,ESL)的平均上升速率降至~0.64 mm/a;5 ka以来,甚至不再上升。7 ka以来,渤海湾西岸相对上升速率是~0.46 mm/a;5.5 ka之后,进一步减弱到~0.18 mm/a。上述全球和渤海湾西岸海面变化,显示出明显的“二段式”上升特点。以~7 ka为转折点:之前与之后的上升速率相差一个数量级。对于渤海湾西岸而言,叠加在这个长达~7000年的明显减速但仍缓慢上升背景上的,是均衡掀升分量与下沉(新构造下沉+沉积自压实下沉)分量的相互抵消。于是,全球性海面的缓慢上升、区域性均衡调整造成的掀升与局地下沉,这三者的复杂博弈,形成了长达~7000年的、经常受高潮水影响的渤海湾西岸障壁岛型贝壳堤-潟湖盐沼洼地周期性交替的沿海地形地貌格局。1870 CE至今的150余年间,全球海面平均上升速率~1.7 mm/a,近10余年来更加速至3.7 mm/a,渤海湾同时期I堤海岸线向海侧的前凸岸段平均蚀退1~3 km。【结论】我们推断1870CE以来的全球气温上升-海面上升与渤海湾同时期海岸线蚀退可能具因果关系。21世纪�This paper is the result of Coast Geo-Environment.[Objective]Based on combination between the global sea level history and the reconstruction of the observed local Holocene relative sea level change,this research is aimed at revealing that the sea level change is the most important driving force controlling the land-sea change and morphological pattern transition and future coastal trend in the muddy coast of Bohai Bay,China.[Methods]Modelling effort has reconstructed high-resolution history of the global sea level change since the LGM(e.g.,Lambeck et al.,2014;Peltier et al.,2015),and summarized contributions of various elements to the sea level change(e.g.,Horton et al.,2018).On the other hand,as most coastal geologists,we scrutinized primarily the local and regional elements,which affected the relative sea level(RSL)behaviors in Bohai Bay coast,with quantitative or semi-quantitative estimates(Li et al.,2021;Wang,2022)and more detailed case studies(Fan et al.,2005;Wang et al.,2020;Tian et al.,in review).[Results]The aforementioned approaches indicated global mean sea level(GMSL)rise was~9mm/a during 10~7 ka while the rate of the local relative mean sea(RMSL)was~5.6 mm/a,contemporaneously.Such rapid rises resulted shoreline recession worldwide,including Bohai Sea region with possible inundation of a number of beach ridges.However,after~7ka,rise of the ice-equivalent sea level(ESL)decreased to~0.64 mm/a;after 5 ka,the rise even stopped.As to Bohai Bay,the RMSL rise was~0.46 mm/a after 7 ka and was only~0.18 mm/a since 5.5 ka.Both global and regional sea level changes show obvious two-stage-rise characteristics with a turning-point around 7 ka,before and after which the rise changed greatly with an order of magnitude.Overlapping on the remarkable deceleration is an essential offset between the regional isostatic uplift and the local subsidence of neotectonics and sediment self-compaction.Thus,the triple influences,caused by slowing rise of sea level,isostatic uplift and local subsidence,created a nearly~7 ka long m

关 键 词：历史海面变化 障壁岛型贝壳堤-潟湖盐沼过程终止 海面加速上升 可容空间增加 海岸线蚀退 

分 类 号：P736.2[天文地球—海洋地质]