Anomalous Geomagnetic Field Modeling for Crustal Structure of a Graben in West Siberia  

作　　者：Nikolay Pavlovich Kostrov Kirill Svjatoslavich Ivanov 

机构地区：[1]Institute of Geology and Geochemistry, Urals Branch of Russian Academy of Sciences, Yekaterinburg, Russia

出　　处：《Open Journal of Geology》2018年第3期232-246,共15页地质学期刊（英文）

摘　　要：An intensive magnetic anomaly within the limits of West Siberia Danilov graben-rift indicates magnetic rocks while numerous wells encountered only weakly magnetized Triassic basalts and liparites in the basement covered by thick loose Jurassic and younger sediments. The wells penetrated only the first tens meters of the basement and could not tell us about the liparites structure at depth where supposedly they may form a big single body and magnetic rocks may be situated deeper. Geological ideas on a graben-rift structure may be proved (or rejected) by a computer modeling of its magnetic properties. For the anomalous geomagnetic field interpretation, a method of volume integral equations taking into account demagnetization effect was employed. To fit a model a trial-and-error procedure was utilized. The results show that 1) at the depth some rocks are magnetized in opposite direction to the present field;2) highly magnetized rocks (magnetic susceptibility 0.06 - 0.1SI) coming up continuously from the bottom of the model and situated under the graben;3) the studied structure is not a graben but the rift because the continental light crust is absent.An intensive magnetic anomaly within the limits of West Siberia Danilov graben-rift indicates magnetic rocks while numerous wells encountered only weakly magnetized Triassic basalts and liparites in the basement covered by thick loose Jurassic and younger sediments. The wells penetrated only the first tens meters of the basement and could not tell us about the liparites structure at depth where supposedly they may form a big single body and magnetic rocks may be situated deeper. Geological ideas on a graben-rift structure may be proved (or rejected) by a computer modeling of its magnetic properties. For the anomalous geomagnetic field interpretation, a method of volume integral equations taking into account demagnetization effect was employed. To fit a model a trial-and-error procedure was utilized. The results show that 1) at the depth some rocks are magnetized in opposite direction to the present field;2) highly magnetized rocks (magnetic susceptibility 0.06 - 0.1SI) coming up continuously from the bottom of the model and situated under the graben;3) the studied structure is not a graben but the rift because the continental light crust is absent.

关 键 词：Graben-Rift GEOMAGNETIC ANOMALY Modeling Integral Equation Interpretation 

分 类 号：R73[医药卫生—肿瘤]