On the biogenic origin of magnetite and greigite in water basin sediments and soils

The results of long-term observations of the formation of magnetically ordered minerals in the cenosis of natural ooze microorganisms are presented. Using the magnetic measurements and the M$\stackrel{..}{o}$ssbauer spectroscopy, the composition of iron-containing minerals has been monitored. The X-Ray diffractometry and light microscopy were also applied to investigating the ooze magnetic fraction. The formation of magnetite and greigite has been established, leading to increased values of the ooze magnetic parameters. The residual magnetization exceeds the natural magnetization of soils by 4-5 orders of magnitude. The saturation magnetization and the initial magnetic susceptibility have respectively increased by 3 orders of magnitude and by a factor of 15.