摘要
华南板块的显生宙古地磁数据时空分布不均,特别是早古生代的古地磁数据相对匮乏,这限制了对华南板块在早古生代古地理位置的精确刻画.为寻找合适的地层以进行系统的古地磁学研究,本文选取华南板块西北缘镇巴地区所出露的寒武纪纽芬兰统—第二统的牛蹄塘组、西王庙组泥岩-粉砂岩地层进行了岩相学、岩石磁学及磁组构研究.结果表明该套地层的载磁矿物主要为钛赤铁矿、磁铁矿、磁黄铁矿,磁组构整体表现为沉积-弱变形磁组构特征.通过上述研究,本文认为镇巴地区的大部分寒武纪地层并未遭受强烈的构造活动改造,有希望保留了地层沉积时期的原生特征剩磁,适于开展后续的系统退磁工作,有望推动华南板块古地理演化的深入研究.
The spatial and temporal distribution of the palaeomagnetic data of the South China Block is uneven,which limits our understanding of the paleogeography position of the South China Block in the Early Paleozoic.To search for suitable strata for systematic study of paleomagnetism,this study carries out a combined study including petrography,rock magnetism,and magnetic fabric on the mudstone-siltstone of the Cambrian strata from the Zhenba area in the northwestern edge of the South China.The results show that the magnetic minerals of the strata are mainly composed of titanium-bearing hematite or magnetite and magnetic pyrite,while the magnetic fabric is characterized by depositional-weakly deformed magnetic fabric.It is concluded that most of the Cambrian strata in this area have not been tensely modified by tectonic activities,and it is expected to retain the primary magnetic component acquired during deposits,which makes it possible to obtain reliable paleomagnetic data.
作者
李清山
赵杰
陈有炘
刘成军
裴磊
李佐臣
裴先治
王茂
纪尚
LI QingShan;ZHAO Jie;CHEN YouXin;LIU ChengJun;PEI Lei;LI ZuoChen;PEI XianZhi;WANG Mao;JI Shang(School of Earth Science and Resources,Chang'an University,Xi'an 710054,China)
出处
《地球物理学进展》
北大核心
2025年第5期1919-1933,共15页
Progress in Geophysics
基金
国家自然科学基金面上项目(42072261)
青藏高原第二次科学考察(2019QZKK0704)
长安大学中央高校基本科研专项资金-基础研究培育项目(300102273103)联合资助。
关键词
华南北缘
寒武纪
磁组构
岩石磁学
古水流
构造变形
The northern margin of the South China Block
Cambrian
Magnetic fabrics
Rock magnetism
Paleocurrent
Tectonic deformation
