It is generally acknowledged that geomagnetic polarity has reversed many times in geological history and an abnormal geologic phenomenon is the Cretaceous normal superchron. However, the causes have been unknown up to...It is generally acknowledged that geomagnetic polarity has reversed many times in geological history and an abnormal geologic phenomenon is the Cretaceous normal superchron. However, the causes have been unknown up to now. The nonlinear theory has been applied to analyze the phenomenon in geomagnetic polarity reversal and the Cretaceous normal superchron. The Cretaceous normal superchron implies that interaction of the Earth＇s core-mantle and liquid movement in the outer core may be the lowest energy state and the system of Earth magnetic field maintains a sort of temporal or spatial order structure by exchanging substance and energy in the outside continuously. During 121-83 Ma, there was no impact of a celestial body that would result in a geomagnetic polarity reversal, which may be a cause for occurrence of the Cretaceous normal superchron.The randomness of geomagnetic polarity reversal has the self-reversion characteristic of chaos and the chaos theory gives a simple and clear explanation for the dynamic cause of the geomagnetic polarity reversal.展开更多
开展白垩纪超静磁带(Cretaceous Normal Superchron,CNS)短期负极性事件研究对于认识CNS期间地磁场变化特征和地球内部动力学过程具有重要科学意义.云南思茅盆地南部江城剖面出露较为完整的白垩纪地层序列,前期磁性地层学研究显示,剖面...开展白垩纪超静磁带(Cretaceous Normal Superchron,CNS)短期负极性事件研究对于认识CNS期间地磁场变化特征和地球内部动力学过程具有重要科学意义.云南思茅盆地南部江城剖面出露较为完整的白垩纪地层序列,前期磁性地层学研究显示,剖面中上部记录了多个CNS短负极性带.本文针对江城剖面CNS段代表性正、负极性样品开展了详细的岩石磁学、岩相学和古地磁学对比分析,获得以下主要认识和结论:(1)样品记录了原始沉积磁组构,指示沉积地层受后期构造应力或沉积扰动的影响较弱;(2)样品中的载磁矿物主要是碎屑成因赤铁矿和少量的磁铁矿,以单畴特征为主;(3)负极性带样品与正极性带样品的磁组构、载磁矿物、岩相学和退磁特征不存在显著差异,表明这些短负极性带指示了发生在CNS早期(中—晚阿普特期)和末期(早圣通期)的真实地磁倒转事件;(4)江城剖面CNS段的短负极性事件能够与中国大陆酒西、衡阳、松辽盆地以及印支陆块万象盆地记录进行对比.本研究为CNS短期负极性事件提供了新的可靠的陆相沉积证据.展开更多
The passage of our Solar System through the spiral arms has been implicated as a contributor to global environmental perturbations.The suggestion of a consistent structure within the arms,informed by density wave theo...The passage of our Solar System through the spiral arms has been implicated as a contributor to global environmental perturbations.The suggestion of a consistent structure within the arms,informed by density wave theory,raises the possibility of repeating patterns of events at each arm crossing.Here we test the hypothesis that the structure of the arms of our galaxy influences the stratigraphic record on Earth.We construct independent structural and temporal models and colbine these to compare the timings of arm tracers,materials from the earliest Solar System and events on Earth,including the largest extinctions.We find that a recurring sequence of events across the four arms emerges with an average arm-passing time of 188 million years.We suggest that the multiple temporal overlaps of events across arms,and their alignment with arm tracers and the earliest Solar System,presents an opportunity for a greater understanding of both Earth-based phenomena and galactic structure.展开更多
基金supported by the National Basic Research Program of China(Grant No.2006CB701406)the National Natural Science Foundation of China(Grant Nos.40672196 and 40638041)+1 种基金the Laboratory of Resources Environment and Management(Grant No.GPMR0520)and the Project 111(Grant No.B07011).
文摘It is generally acknowledged that geomagnetic polarity has reversed many times in geological history and an abnormal geologic phenomenon is the Cretaceous normal superchron. However, the causes have been unknown up to now. The nonlinear theory has been applied to analyze the phenomenon in geomagnetic polarity reversal and the Cretaceous normal superchron. The Cretaceous normal superchron implies that interaction of the Earth＇s core-mantle and liquid movement in the outer core may be the lowest energy state and the system of Earth magnetic field maintains a sort of temporal or spatial order structure by exchanging substance and energy in the outside continuously. During 121-83 Ma, there was no impact of a celestial body that would result in a geomagnetic polarity reversal, which may be a cause for occurrence of the Cretaceous normal superchron.The randomness of geomagnetic polarity reversal has the self-reversion characteristic of chaos and the chaos theory gives a simple and clear explanation for the dynamic cause of the geomagnetic polarity reversal.
文摘开展白垩纪超静磁带(Cretaceous Normal Superchron,CNS)短期负极性事件研究对于认识CNS期间地磁场变化特征和地球内部动力学过程具有重要科学意义.云南思茅盆地南部江城剖面出露较为完整的白垩纪地层序列,前期磁性地层学研究显示,剖面中上部记录了多个CNS短负极性带.本文针对江城剖面CNS段代表性正、负极性样品开展了详细的岩石磁学、岩相学和古地磁学对比分析,获得以下主要认识和结论:(1)样品记录了原始沉积磁组构,指示沉积地层受后期构造应力或沉积扰动的影响较弱;(2)样品中的载磁矿物主要是碎屑成因赤铁矿和少量的磁铁矿,以单畴特征为主;(3)负极性带样品与正极性带样品的磁组构、载磁矿物、岩相学和退磁特征不存在显著差异,表明这些短负极性带指示了发生在CNS早期(中—晚阿普特期)和末期(早圣通期)的真实地磁倒转事件;(4)江城剖面CNS段的短负极性事件能够与中国大陆酒西、衡阳、松辽盆地以及印支陆块万象盆地记录进行对比.本研究为CNS短期负极性事件提供了新的可靠的陆相沉积证据.
文摘The passage of our Solar System through the spiral arms has been implicated as a contributor to global environmental perturbations.The suggestion of a consistent structure within the arms,informed by density wave theory,raises the possibility of repeating patterns of events at each arm crossing.Here we test the hypothesis that the structure of the arms of our galaxy influences the stratigraphic record on Earth.We construct independent structural and temporal models and colbine these to compare the timings of arm tracers,materials from the earliest Solar System and events on Earth,including the largest extinctions.We find that a recurring sequence of events across the four arms emerges with an average arm-passing time of 188 million years.We suggest that the multiple temporal overlaps of events across arms,and their alignment with arm tracers and the earliest Solar System,presents an opportunity for a greater understanding of both Earth-based phenomena and galactic structure.
