The role of organic matter in the formation of fireproof clay of the Latnenskoe deposit

634 Organic matter of vegetal and (or) bacterial origin in the Earth's crust under the conditions of hypergen� esis carries two functions: destructive, providing decomposition and dissolution of primary minerals, and creative, which controls incorporation of mineral� ized organic remnants in the composition of new hypergene formations. Biomineral interactions and their role in mineral formation are related to one of the most important problems of the twentyfirst century in mineralogy (1, 2). It has become much more evident that bacteria occur in all environments and on all sur� faces and that they actively participate in rock weath� ering, material transportation, sedimentation, and diagenesis. Biofilms and cyan bacterial mats play an important role in the processes of mineral formation as well (3). Additional support for these facts was obtained during study by a scanning (SEM) and trans� mitting (TEM) electron microscopy, thermal analysis, and IRspectroscopy of fireproof clay from the Latn� enskoe deposit; as a result, the interaction between organic and inorganic materials during their forma� tion was originally discovered. The deposit is located in 15 km to the west of Vor� onezh in the Don-Veduga-Devitsa interfluves. Clay composes oval lenses with a width of several hundred meters and a length of a few kilometers; it occurs in the middle part of the section of sand-gravel alluvial deposits of Aptian age. The thickness of productive horizon ranges from n to 40 m; the average thickness of proper fireproof clay is 3-4 m. Clay is mainly com� posed of kaolinite, the concentration of which is 70- 90%. Terrigenous hydromica and quartz, as well as authigenous montmorillonite and gibbsite, usually