Understanding the enhanced magnetization intensities of post-20 Ma oceanic basalts through magneto-mineratogical experiments

海洋玄武岩的磁化强度随时间变化，在海洋磁异常剖面中清晰可见。从现在到过去，强度下降到20 Ma左右，然后稳步增加，直到白垩纪。钛磁铁矿在低温下氧化为钛磁铁矿，可以解释初始强度下降的原因；然而，20 Ma以上的海洋玄武岩随后磁化强度增加的原因尚不清楚。我们建议测试磁矿物学变化是磁化增加的潜在原因的可能性。人们设想了两种潜在的磁矿物学变化——这两种变化都将通过结合电子探针分析、古强度实验和岩石磁性表征来检验。原子力显微镜（AFM），磁力显微镜（MFM）或Mössbaur光谱学也将根据情况使用。将这种新的尖端技术与更经典的实验结合起来，将极大地限制地球科学中尚未解决的一级问题。

The magnetization intensities of oceanic basalts vary through time, being clearly visible in marine magnetic anomaly profiles. Going from the present to the past, intensities decrease until around 20 Ma, and then they steadily increase until the Cretaceous. The initial decrease in intensity can be explained by low temperature oxidation of titanomagnetite to titanomaghemite; however, the cause for the subsequent increase in magnetization for oceanic basalts older than 20 Ma is unknown. We propose to test the possibility that magneto-mineralogical changes are the underlying cause of the magnetization increase. Two potential magneto-mineralogical changes are envisaged—both will be examined by combining electron microprobe analyses, paleo-intensity experiments and rock magnetic characterization. Atomic Force Microscopy (AFM), Magnetic Force Microscopy (MFM) or Mössbaur spectroscopy will also be employed depending on the case. Employing this new, cutting-edge technology together with the more classical experiments should significantly constrain a first-order, yet still unresolved, problem in the Earth sciences.