辽东湾北部JXC-1孔稀土元素组成与物源判别  

RARE EARTH ELEMENT COMPOSITIONS AND PROVENANCE OF SEDIMENTS FROM CORE JXC-1 IN THE NORTHERN LIAODONG BAY

作　　者：王忠蕾[1,2] 梅西 郑洪波[3] 孟祥君 密蓓蓓[1] 蓝先洪[1] 孙军[1] WANG Zhonglei;MEI Xi;ZHENG Hongbo;MENG Xiangjun;MI Beibei;LAN Xianhong;SUN Jun(Qingdao Institute of Marine Geology,Qingdao 266071,Shandong;School of Geography,Nanjing Normal University,Nanjing 210023,Jiangsu;Research Center for Earth System Science,Yunnan University,Kunming 650091,Yunnan)

机构地区：[1]青岛海洋地质研究所,山东青岛266071 [2]南京师范大学地理科学学院,江苏南京210023 [3]云南大学地球系统科学研究中心,云南昆明650091

出　　处：《第四纪研究》2021年第1期28-42,共15页Quaternary Sciences

基　　金：中国地质调查局海洋地质调查专项项目(批准号:GZH201400205、DD20190208和DD20160137);中国科学院(B类)战略性先导科技专项项目(批准号:XDB26020301);中国科学院边缘海重点实验室基金自主项目(批准号:MSGL15-06);科技部基础性工作专项项目(批准号:2013FY112900)共同资助。

摘　　要：黄河对渤海海底沉积物贡献量巨大,但黄河物质进入渤海后向北扩散的范围尚不明确。本文对位于辽东湾北部海域岩芯总长为62.68 m的JXC-1孔1.2 Ma以来沉积物稀土元素进行测试分析,结合岩性、粒度参数和测年数据,研究了钻孔稀土元素垂向变化的影响因素,并对其物质来源变化进行了探讨。研究表明,沉积环境变化导致沉积物粒度和物质组成差异,钻孔沉积物的ΣREE与粒度变化有一定的相关性,但ΣLREE/ΣHREE、(La/Yb)N和δEu等参数不受粒度控制。稀土元素分异参数有效示踪了物质来源,经对比,JXC-1孔沉积物分异参数特征与南部的黄河和北部的辽河(原双台子河)、大辽河沉积物较为一致,而与滦河和复州河有明显不同;结合判别函数(FD),推测JXC-1孔沉积物早更新世晚期以来主要来由南部的黄河和北部的辽河、大辽河搬运而来。分析结果表明,17.00 m以上层位为晚更新世沉积,0~2.00 m、4.00~11.00 m和14.00~16.00 m可能为海相地层,渤海环流将黄河入海物质向东北扩散的一支输送至辽东湾北部,同时接受潮流作用输送的北部辽河和大辽河细粒物质,但总体以黄河输送物质占主导;17.00 m以下层位主要为早更新世晚期以来的陆相沉积,以湖相环境为主,物源受距离河口远近和沉积物通量影响。36.00~48.00 m和58.00~70.30 m为湖相高水位期,古黄河水系流路可能位于现今流路以北的区域,受湖流等沉积动力影响,黄河输送物质扩散范围较广,对钻孔沉积物影响较大;在48.00~58.00 m低水位时期,钻孔沉积物以距离较近的北部辽河和大辽河输送物质占主导。16.40~36.00 m主要为河流相,物源复杂,但在26.00~36.00 m层位明显受辽河和大辽河影响较大。上述分析结果显示黄河东流入海(渤海古湖)以后,受海洋环流、距离河口远近和湖泊沉积动力等因素控制,携带沉积物扩散范围可以到达40.5°N左右或者以北的区域。本The contribution of the Yellow River to the bottom sediments of the Bohai Sea is huge,but the extent of the material diffusion from the Yellow River to the north after entering the Bohai Sea is not clear.In this paper,REE in the sediments of JXC-1 borehole located in the northern sea area of Liaodong Bay since 1.2 Ma was analyzed,and the composition characteristics of REE in the sediments of the borehole were studied.The JXC-1 borehole is located at 40°24’43.38″N,121°03’23.37″E,where the water depth is about 22 m.The drilling footage of the JXC-1 borehole is 70.30 m with the coring rate of 89.2%,and a total core of 62.68 m is obtained.Combined with lithology,grain size parameters and dating data,the influencing factors of the vertical change of REE in the borehole were studied,and the material sources were discussed.The results show that the variation of sedimentary environment results in the difference of sediment grain size and sediments composition.There is a certain correlation betweenΣREE and grain size variation,but the value ofΣLREE/ΣHREE,(La/Yb)NandδEu are not controlled by grain size.Through comparison,the characteristics of core JXC-1 sediment differentiation parameters are consistent with those of modern Yellow River in the South and Liaohe River(former Shuangtaizi River)and Daliao River in the north,but obviously different from those of Luanhe River and Fuzhou River.Combined with the discriminant function FD,it is speculated that the sediments of JXC-1 borehole mainly come from the Yellow River in the South and the Liaohe River and Daliao River in the north since the Middle Pleistocene.The strata above17.00 m were formed in the Late Pleistocene,of which 0~2.00 m,4.00~11.00 m and 14.00~16.00 m may be marine strata.The material carried by the Yellow River diffuses to the northeast and is transported to the north of Liaodong Bay under the influence of Bohai circulation.At the same time,Liaodong Bay receives the fine-grained materials transported by Liaohe River and Daliao River by tidal cur

关 键 词：辽东湾钻孔 稀土元素 组成 物源 

分 类 号：P722.4[天文地球—海洋科学] P595[天文地球—地球化学]