Complex sentence: Other methods such as transmission electron microscopy (TEM) of samples from deep boreholes and ferromagnetic resonance (FMR) spectroscopy of chains of cultured magnetotactic bacteria compared to sediment samples are being used to infer magneto fossil preservation over geological time frames.
Split into simpler sentences: Other methods such as transmission electron microscopy (TEM) of samples from deep boreholes and ferromagnetic resonance (FMR) spectroscopy are being used. FMR spectroscopy of chains of cultured magnetotactic bacteria compared to sediment samples are being used to infer magnetofossil preservation over geological time frames.