Salt Tectonics and Basin Evolution in the Gabon Coastal Basin,West Africa

来源 :Journal of Earth Science | 被引量 : 0次 | 上传用户:xuxiaorou12345
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The Gabon Coastal Basin is a typical saliferous basin located in the middle portion of the West African passive continental margin.Complex salt tectonics make sedimentary sequences and structural frameworks difficult to interpret and can lead to difficulties in construction of balanced cross-sections and reconstruction of basin evolutionary processes.Sedimentary facies and salt structural patterns displaying zonation are based on seismic reflection profiles and drilling data.Two near-vertical fault systems,NW-SE and NE-SW,caused basin to be subdivided E-W zoning and N-S partitioning.Scarp slopes and extension faults formed in the Hinge belt III zone where salt diapir piercement occurred and numbers of salt pillars,salt stocks and salt rollers developed under transtension of coupled near-orthogonal fault systems.The zone east of Hinge belt III is characterized by small-scale salt domes and salt pillows.To the west are large-scale salt walls and salt bulge anticlines caused by diapirism promoted by tension and torsion that also resulted in formation of numerous salt pillars,salt stocks and salt rollers.Our modeling of salt tectonic structures indicates that they were produced by plastic rheological deformation of salt under regional stress fields that varied during three distinct phases of extension,compression and re-activation.Hinge belt III was active from Coniacian to Early Eocene,which was a critical period of formation of salt structures when many extension-related salt structures formed and salt diapirism controlled the distribution of turbidite fans.Rootless extrusion-related salt stocks developed throughout the Late Eocene to Early Oligocene as a result of local ephemeral low-intensity tectonic inversion.Post Oligocene salt diapirism was weak and salt tectonics had a weak influence on sedimentation.Balanced cross-sections of two saliferous horizons crossing different tectonic units from east to west reveal that the basin tectonic evolution and sediment filling processes can be divided into three stages containing seven episodes of rifting,transition and drifting. The Gabon Coastal Basin is a typical saliferous basin located in the middle portion of the West African passive continental margin. Complex salt tectonics make sedimentary sequences and structural frameworks difficult to interpret and can lead to difficulties in construction of balanced cross-sections and reconstruction of basin evolutionary processes.Sedimentary facies and salt structural patterns displaying zonation are based on seismic reflection profiles and drilling data. TW near-vertical fault systems, NW-SE and NE-SW, caused basin to be subdivided EW zoning and NS partitioning. extension faults formed in the Hinge belt III zone where salt diapir placement occurred and numbers of salt pillars, salt stocks and salt rollers developed under transtension of coupled near-orthogonal fault systems. The zone east of Hinge belt III is characterized by small-scale salt domes and salt pillows.To the west are large-scale salt walls and salt bulge anticlines caused by diapirism promoted by tension and torsion that also resulted in formation of numerous salt pillars, salt stocks and salt rollers. Our modeling of salt tectonic structures indicates that they were produced by plastic rheological deformation of salt under regional stress fields that varied during three distinct phases of extension , compression and re-activation. Hair belt III was active from Coniacian to Early Eocene, which was a critical period of formation of salt structures when many extension-related salt structures formed and salt diapirism controlled the distribution of turbidite fans. salt stocks developed throughout the Late Eocene to Early Oligocene as a result of local ephemeral low-intensity tectonic inversion. Post Oligocene salt diapirism was weak and salt tectonics had a weak influence on sedimentation. Balanced cross-sections of two saliferous horizons crossing different tectonic units from east to west reveal that the basin tectonic evolution and sediment filling processes can be divided into three stages containing seven episodes of rifting, transition and drifting.
其他文献
高中英语是高中课程中非常重要的内容,英语之所以重要,不仅仅是因为英语是高考内容中重要的组成部分,更是因为学生良好的英语水平对于学生未来的发展有非常重要的意义。同时,
期刊
摘要:随着新媒体的发展以及由此引发的我国舆论环境的不断改变,电视作为传统主流媒体在突发事件报道中需要充分发掘自身优势,以全新的思维和理念应对新媒体所带来的各种挑战,化“危”为“机”,重新树立电视新闻媒体的品牌形象。  关键词:电视媒体 突发事件 新媒体    2011年1月24日发生的莫斯科多莫杰多沃机场自杀式爆炸事件在让人们悲痛不已的同时,也让国人再次感受到了新媒体在突发事件报道中的巨大影响力。
Objective:To investigate the clinicopathologic characteristics of the primary synchronous multiple gastric cancers(SMGC) in Chinese.Methods:Clinicopathologic da
PURPOSE: To assess the value conferred by photodynamic therapy (PDT) and the cost-utility of PDT for the treatment of classic, subfoveal choroidal neovasculariz
Objective and Methods The key cause of failure to cure and high mortality in lung cancer. At present, it has been known that Objective and Methods The key caus
日本喜剧导演伊丹十三拍摄的电影《蒲公英》在日本国内外均有极大的影响力。这部影片包含了不少日本文化的要素,成为许多人了解日本文化的重要窗口。本文主要通过分析《蒲公
一、初中英语情境教学之误区一是初中英语情境教学的教学认识误区。初中学生在英语学习过程中接触到的都是基础词汇、简单句式和英语语法,因此部分学生、家长和英语教师忽视
A connection ensemble model (CEM) of local neural circuits in central nervous system(CNS) is proposed in this work.Neuronal interactions are investigated at two
据日本大藏省贸易统计,在1994年1~8月的半导体存储器输入总量2.5902亿块中,韩国有1.05亿块,占整个输入量的40.7%,上年同期为35.6%。从韩国进口的品种大多为4MbDRAM。美国DR/^iM需要看好,而
从两个角度谈了一下教学心得。首先提出物理学习需要思考的建议,而后对师德进行了细致入微的诠释。 Talk about teaching ideas from two perspectives. First of all, we p
期刊