【摘要】 风火山白垩系紫色砂岩样品的矿物学分析结果表明,大部分样品的磁性载体是铁白云石.根据退磁曲线估计其居里点为500℃左右.当退磁温度增加到600℃左右,铁白云石开始分解,形成磁铁矿,致使样品在此温度段退磁时,其磁性不但不减小反而骤然增加,甚至可达天然剩磁的十几倍,其原生成分受到破坏.因此,在低于居里点温度确定的本征剩磁及相应的古地磁数据将能反映特定的地质意义.由风火山白垩系古地磁数据可见,青藏高原巴颜喀拉地体白垩系以后仍然存在着较大规模的北向移动.更多还原

【Abstract】 Ferrodomite is the main magnetis carrier in the Cretacous violet sandstone on Fenghuo mountains. It’s curie point is about 500℃. When demagnetic temperature rise up to 600℃, ferrodoiornite begins dissociating and forms magnetite, this results in intensification of the specimen magnetism, and modifies specimen’s primary mineral component. Thus, primary steady remanence can be determined on the basis of intri-insic remanence at the temperature lower than curie point. The Cretaceous palaeomagnetic data indicates that the Bayanhar terrane in Qinghai-Tibet plateau had a larger movement to the north after Cretaceous.更多还原