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蛇纹岩在大洋地壳性质、俯冲带地球化学、岛弧岩浆活动和镍矿床形成等地质过程中具有重要作用.以北大西洋大洋钻探钻孔ODP 897D和1070A孔的蛇纹岩为研究对象,综合磁学和地球化学研究,探讨了蛇纹岩样品的磁性矿物组成和变化机制.结果表明,钻孔中的载磁矿物主要为磁铁矿,在钻孔基岩的上段与顶部发育部分磁赤铁矿.蛇纹石化过程决定着铁在不同矿物相之间的分配状态,裂隙发育状态以及流体活动性等因素制约着磁铁矿的产出.通过钻孔对比,发现蛇纹石化过程中磁铁矿的产生机制单一,但是低温氧化过程持续时间的不同造成了不同钻孔之间的磁学性质差异.研究结果有助于理解蛇纹石化橄榄岩磁性增强机理,为合理解释该区航磁异常以及古地磁信息提供了新思路.
Serpentinite plays an important role in the geological processes of oceanic crust, geochemistry of subduction zone, magmatic activity of island arc and formation of nickel deposit, etc. Taking the serpentinite of ODP 897D and 1070A boreholes drilled in the North Atlantic Ocean for drilling, Magnetism and geochemistry, the magnetic mineral composition and variation mechanism of serpentinite samples are discussed.The results show that the magnetite-bearing minerals in the boreholes are mainly magnetite, and the magnetite The serpentinization process determines the distribution of iron between different mineral phases, the development of fractures and fluid activity and other factors restrict the output of magnetite.According to the comparison of drilling and drilling, it is found that during the process of serpentinization The mechanism of iron ore generation is single, but the differences of the magnetic properties between different boreholes caused by the different durations of the low-temperature oxidation process will help to understand the magnetic enhancement mechanism of serpentinized peridotite. To reasonably explain the aeromagnetic Abnormal and paleomagnetic information provides a new idea.