Boreskov

PP‐29picture there is Mossbauer spectra of the nodules both untreated and heated up to definitetemperatures. According to the Mossbauer spectra of the heated nodules first of all‐FeOOH and more slowly another Fe‐Mn oxide mineral are transformed into a new Fephases with the sextet magnetic spectrum structure. The end annealing products arehematite ‐Fe 2 O 3 and its Mn‐ analogue (Mn,Fe) 2 O 3 . Hematite determines magneticstructure of spectra and contains about 70% of Fe.The detailed study of the nodule outer surface revealed that Fe‐Mn oxides form eitherleakage structures consists from nanoscale flakes or micriglobules. Among the structures themost common are Fe‐Mn spherulites with the addition of phosphorus in the composition (inwt.%): MgO –1.84; Al 2 O 3 –5.96; SiO 2 –15.97; P 2 O 5 –3.56; K 2 O – 1.20; CaO – 2.20; MnO –18.52; Fe 2 O 3 –24.54; ВаО – 0.77. The size of such flakes is not more than 2 microns. Thenodule surface is also consisting of nanoscale flakes. Such surface structure is analogous(similar) to bacterial forms with the cover from mineralized glycocalyx. Similar types ofbacteria have been discovered in the ferromanganese nodules of the Pacific Ocean.Globular structures are typical not only for the surface of the nodules. We discoverednumerous pyrite microglobules with the surfaces indistinguishable from the surfaces offerromanganese nodules. The ability of biogenic pyrite formation is widely discussed andnow is undoubted.Inner structure of is quite different from the outer (surface) one. There are no globularforms at the inner parts of the globules. Fe‐Mn oxides formed nanoscale “net”. At suchconditions mineralization processes occur very fast. This resulted in the fact that we canobserved only uncrystalline phases (not crystalline) what is typical for biogenicmineralization.Recently the role of biogenic factor in mineral formation is discussed very wide from thedifferent positions. Microorganisms are regarded as “accumulators” of some elements thatare necessary for mineral formation at definite conditions; they can influence on the mineralsubstance during biofilm formation on the mineral surface; microorganisms can form someminerals at the processes of their vital functions.The role of biogenic factor at the formation and growth of ferromanganese nodules isdiscussed since their revelation to our time from the different positions and now isundoubted. Nowadays only ideas about the forms of biogenic formation and range of itimportance can be changed. Today biogenic factor is regarded in different aspects: as sourceof nodule nuclei, as element supplier for nodule growth and so on, up to the ideas aboutstromatolithic nature of the nodules. The most evident participation of biogenic formationsin nodule building is their use as nuclei. This process is so widespread that the separatebiomorphogenic type is separated among the nodule morphotypes. Into this morphotype184