| 渤海湾西岸BT113孔35ka以来的沉积环境演化与海陆作用 |
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| 引用本文： | 陈永胜,王宏,李建芬,裴艳东,田立柱,商志文.渤海湾西岸BT113孔35ka以来的沉积环境演化与海陆作用[J].吉林大学学报(地球科学版),2012(Z1):344-354. |
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| 作者姓名： | 陈永胜 王宏 李建芬 裴艳东 田立柱 商志文 |
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| 作者单位： | 吉林大学地球科学学院;中国地质调查局天津地质调查中心 |
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| 基金项目： | 中国地质调查局项目(1212010814004,1212011120169) |
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| 摘 要： | 根据渤海湾西岸有孔虫和介形虫与年代学(AMS14C和OSL测年)研究,将该段岩心自下而上划分为6个沉积单元(U1—U6),它们依次形成于晚更新世的河流及全新世的潮滩、浅海、前三角洲、三角洲前缘和三角洲平原沉积环境,结束于约35 ka的U1单元的陆相环境,证实晚更新世低海面时渤海湾西岸未受海水影响。U1和U2单元之间,存在历时约27 ka的沉积间断(35～8.5 ka cal BP),研究区因此缺失早全新世沉积。U2单元的潮滩环境指示全新世海侵于8.5 ka cal BP到达渤海湾西岸,当时相对海平面为-16.7 m。U3单元为浅海环境,约6 ka cal BP时相对海平面上升到-6.8～-1.8 m。8.5～6 ka cal BP期间的海面上升速率是0.4～0.6 cm/a,可能与MWP1C事件有关。U4—U5单元,转为三角洲环境,沉积速率增大,反映自3.7 ka cal BP河流输入影响加强,约1.3 ka cal BP时成陆,形成U6单元。晚更新世35 ka以来的陆海环境演化,总体上是对气候变化控制下的海面变化的响应。
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| 关 键 词： | 渤海湾西岸 ka cal BP 沉积环境 海平面 河流供给 |
Sedimentary Environment Since 35 ka and Terrestrial-Marine Interaction Revealed by Borehole BT113 in the Western Coast of Bohai Bay,China |
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| Chen Yong-sheng,Wang Hong,Li Jian-fen,Pei Yan-dong,Tian Li-zhu,Shang Zhi-wen.Sedimentary Environment Since 35 ka and Terrestrial-Marine Interaction Revealed by Borehole BT113 in the Western Coast of Bohai Bay,China[J].Journal of Jilin Unviersity:Earth Science Edition,2012(Z1):344-354. |
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| Authors: | Chen Yong-sheng Wang Hong Li Jian-fen Pei Yan-dong Tian Li-zhu Shang Zhi-wen |
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| Institution: | 1.College of Earth Sciences,Jilin University,Changchun 130061,China 2.Tianjin Centre of China Geological Survey,CGS,Tianjin 300170,China |
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| Abstract: | A sediment core of BT113 was obtained from the western coast of Bohai Bay,and the uppermost 20 m sector was well analyzed in sedimentary petrology,assemblages of foraminifera and ostracoda,accelerator mass spectrometry(AMS) 14C and optically stimulated luminescence(OSL) dating to reconstruct the sedimentary environment during the last 35 ka.The 20 m core was distinguished and interpreted as following six depositional units(Unit 1 to 6 in ascending order): Unit 1 is recognized as fluvial facies deposited in the Late Pleistocene;Unit 2,tidal flat;Unit 3,shallow sea;Unit 4,prodelta;Unit 5,delta front and Unit 6,delta plain facies.Units 2 to 6 were all deposited during the Holocene period.As being the terrestrial environment,Unit 1,ended at ca.35 ka,indicates there was not marine influence during the Late Pleistocene sea level lowstand.There existed a 27 ka-long hiatus ranging in 35-8.5 ka cal BP.Thus,lacking of the Early Holocene is plausible.Unit 2,tidal flat sediment,indicates the Holocene marine transgression did not reach the study area until ca.8.5 ka cal BP and then relative sea level was-16.7 m.Unit 3,shallow marine,shows the relative sea level rose to-6.8 to-1.8 m at ca.6 ka cal BP.Rate of sea level rise of 0.4-0.6 cm/a,possibly,corresponded with MWP1C event.Units 4 and 5 had changed to deltaic facies,with increased sedimentation rates,showing strengthening of fluvial influence since 3.7 ka cal BP.After ca.1.3 ka cal BP,Unit 6 was formed.Generally,the environmental revolution since the last 35 ka was governed mainly by sea level changes. |
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| Keywords: | western coast of Bohai Bay 35 ka cal BP revolution of sedimentary environment sea level sediment supply |
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