长江中下游水阳江流域BZK0402孔多重地层划分及其冰后期海平面变化的沉积响应  

Multi-stratigraphic study and response to sea-level fluctuations since the last deglaciation detected from BZK0402 core in the Shuiyang River basin,Yangtze River

作　　者：陈忠良[1,2] 张晋喆 沈仕豪 黄蒙 徐锦龙[1] 葛海影[1] Simon M.Jowitt CHEN Zhongliang;ZHANG Jinzhe;SHEN Shihao;HUANG Meng;XU Jinglong;GE Haiying;Simon M.Jowitt(Geological Survey of Anhui Province,Hefei 230001,Anhui,China;School of Resources and Environment Engineering,Hefei University of Technology,Hefei 230009,Anhui,China;Department of Geoscience,University of Nevada Las Vegas,Las Vegas89154-4010,Nevada,USA)

机构地区：[1]安徽省地质调查院,安徽合肥230001 [2]合肥工业大学资源与环境工程学院,安徽合肥230009 [3]内华达大学拉斯维加斯分校地球科学学院,内华达州拉斯维加斯89154-4010

出　　处：《中国地质》2022年第2期655-666,共12页Geology in China

基　　金：中国地质调查局地质调查项目(DD20160036,DD20190043);安徽省自然科学基金青年项目(1808085QD116)联合资助。

摘　　要：【研究目的】开展水阳江流域标准孔BZK0402孔多重地层划分,探讨长江支流水阳江流域冰后期海平面变化的沉积响应以及古丹阳湖的成因和形成时代。【研究方法】以岩石地层为基础,在磁性地层和年代地层的双重约束下,对BZK0402孔进行多重地层划分。对比分析BZK0402孔和长江河谷、长江三角洲等邻区钻孔。【研究结果】BZK0402孔第四纪地层可划分为中—下更新统大桥镇组、全新统芜湖组。钻孔所属的长江三角洲西缘河湖环境沉积物对末次盛冰期以来海平面升降和气候变化存在沉积响应:末次盛冰期,长江中下游河流比降大,区内河流侵蚀作用强烈,沉积物以砂砾石层为主;全新世早期,区内受冰后期海侵影响,沉积物粒度逐渐变细,沉积环境由河漫滩相向湖相过渡。植被覆盖类型以针叶林为主,林下蕨类植物生长茂盛。平原地区发育湖泊沼泽;全新世中期,海侵逐渐至最大,区内发育湖相淤泥质黏土。森林面貌以针叶-落叶阔叶混交林为主;全新世晚期至今,区内沉积物有扰动现象。【结论】长江支流水阳江河谷中不仅是全新世沉积,还发育更新世沉积。水阳江流域内古丹阳湖形成于全新世早期,其形成与全新世海侵在时间上存在一致性。This paper is the result of environmental geological survey engineering.[Objective]To carry out multi-stratigraphic research on the borehole BZK0402 located in the Shuiyang River basin,and explore the sea-level fluctuations since the last deglaciation and the origin of the Paleo-Danyang Lake formation.[Methods]Based on the lithostratigraphical classification and the magnetostratigraphic and chronostratigraphical constraints,the multi-stratigraphic study on the BZK0402 core was carried out.Comparative analysis was also been made between the BZK0402 core and the cores which located in the Yangtze River valley and the Yangtze River delta.[Results]The analysis divided the BZK0402 core within Quarternary era into two units,namely the Middle-Upper Pelistocene Daqiaozhen Formation and the Holocene Wuhu Formation.The sediments through the western margin of the Yangtze River delta where the BZK0402 core lies in,also furthers our understanding of the general pattern of sea-level change since the Last Glacial Maximum(LGM),with these changes divided into four stages as follows:(1)The LGM was associated with a period of gravel and sand dominated deposition as a result of steep slopes and significant strong fluvial erosion within the Middle and Lower Reaches of the Yangtze River.(2)The Early Holocene saw a decrease in the grainsize of the sediments being deposited,with sedimentary facies changing from fluvial to lacustrine environments as a result of post-glacial transgression.This period also saw the development of pteridophyte undergrowth-dominated coniferous forest vegetation along with lakes and bog and swamp areas.(3)The Middle Holocene transgressive maximum was associated with the deposition of lacustrine clays that contain coniferous broad-leaved mixed forest vegetation.(4)These sediments are overlain by disturbed Late Holocene to present sediments,with this disturbance caused by uncertain factors.[Conclusions]The sediments in the Shuiyang River,which is a tributary of Yangzte River,not only formed within Holecene,but a

关 键 词：磁性地层 ^(14)C测年 光释光测年 古丹阳湖 全球气候变化 环境地质调查工程 长江 

分 类 号：P534.63[天文地球—第四纪地质学]