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秦亚超,顾兆峰.连云港海域废黄河水下三角洲北翼的沉积特征与空间分布[J].海洋学报,2019,41(11):101-116
连云港海域废黄河水下三角洲北翼的沉积特征与空间分布
The depositional feature and spatial distribution of the northern flank of the abandoned subaqueous Yellow River Delta off the Lianyungang coast, western South Yellow Sea
投稿时间:2018-10-23  修订日期:2018-12-16
DOI:10.3969/j.issn.0253-4193.2019.11.010
中文关键词:  浅地层剖面  柱状沉积物  三角洲前缘  前三角洲  海侵沉积  南黄海
英文关键词:shallow seismic profile  sediment core  delta front  prodelta  transgressive deposits  South Yellow Sea
基金项目:自然资源部海洋区域地质调查项目(GZH201400206)。
作者单位
秦亚超 青岛海洋地质研究所 自然资源部天然气水合物重点实验室山东 青岛 266071
青岛海洋科学与技术试点国家实验室 海洋矿产资源评价与探测技术功能实验室山东 青岛 266071 
顾兆峰 青岛海洋地质研究所 自然资源部天然气水合物重点实验室山东 青岛 266071
青岛海洋科学与技术试点国家实验室 海洋矿产资源评价与探测技术功能实验室山东 青岛 266071 
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中文摘要:
      基于连云港海域浅地层剖面资料解释和16个站位柱状岩心的剖面观察、粒度分析、微体化石鉴定、有孔虫和腹足类纹沼螺的AMS 14C年龄,分析废黄河水下三角洲北翼的沉积结构、厚度和沉积物组成,划分沉积单元及其分布范围;识别海侵沉积区的沉积相,认识其沉积环境特征。结果表明,水下三角洲沉积体可分为三角洲前缘和前三角洲两个沉积单元,两者沿连云港海岸线呈并置关系。三角洲前缘位于埒子口至新淮河口外,为一NNE向进积、NW向倾斜的扇形楔状体,可识别出灌河叶瓣及其以东的叶瓣两个沉积中心。该沉积单元以砂质沉积为主,两个叶瓣之间的分流间湾分布有泥和砂质泥。前三角洲位于三角洲前缘西北侧,大致从埒子口外侧沿海岸带向海州湾展布。该单元为泥质沉积,厚度较薄,其北部的两个柱状岩心所揭示的沉积厚度分别为1.8 m和1.5 m。水下三角洲以北,海侵沙席分布广泛,厚度通常在20 cm左右。其分布在本区具有普遍性,只是在连云港海域被黄河泥沙所覆盖,由此也构成了废黄河水下三角洲的底界面。该界面具有侵蚀残留地貌特征。海侵沙席之下为晚更新世MIS 3阶段中早期的海陆过渡相沉积。沉积物多由黄色粉砂或砂质粉砂组成,含有较丰富的有孔虫、介形虫等,可见淡水纹沼螺。
英文摘要:
      Shallow seismic profiles, 16 sediment vibrocores, and AMS 14C ages of foraminifers and a freshwater snail (Parafossarulus striatulus (Benson)) were used to recognize the depositional architecture, the accumulation depths, and the sediment compositions of the northern flank of the abandoned subaqueous Yellow River Delta off the Lianyungang coast, western South Yellow Sea, and further to classify the geographical units and their distribution. The facies of the adjacent shallow transgressive deposits were also distinguished to recognize their paleo-environments. Results show that the subaqueous deposits are divided geographically into two units of delta front and prodelta. Both of them juxtapose along the Lianyungang coast. The delta front is located off the coast between the Liezi River and New Huaihe River mouths. It is a fan-like clinoform, prograding towards NNE and inclining towards NW. It contains two lobes named the Guanhe Lobe and its eastern lobe. Both of them make up the main depocenters. The delta front is mainly composed of sandy deposits, with some muds or sandy muds in the eastern interdistributary bay between the two lobes. The prodelta is located northwest of the delta front, extending off the Liezi River mouth towards Haizhou Bay. It is accumulated by thin mud deposits with vertically homogeneous distribution. Two cores in its northern portion reveal the thicknesses of 1.8 m and 1.5 m, respectively. The transgressive sand sheet is located north of the subaqueous delta, with a thickness of ~20 cm. It is widely present in the study area. Off the Lianyungang coast, however, it is covered by Yellow River-derived sediments and thus underlies the abandoned Yellow River Delta. This sand sheet is characterized by an erosional and relict morphology. Land–sea transition facies are widely present below these transgressive sands, which were formed during the MIS 3 of the Late Pleistocene. It consists of yellow silts or sandy silts, containing many foraminifera and ostracoda as well as freshwater snails.
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