ISSN 0024-4902, Lithology and Mineral Resources, 2013, Vol. 48, No. 5, pp. 384–397. © Pleiades Publishing, Inc., 2013. Original Russian Text © N.S. Bortnikov, V.M. Novikov, A.D. Savko, N.M. Boeva, E.A. Zhegallo, E.B. Bushueva, A.V. Krainov, D.A. Dmitriev, 2013, published in Litologiya i Poleznye Iskopaemye, 2013, No. 5, pp. 426–440. 384 INTRODUCTION Primary and secondary kaolins along with kaolinite clays represent valuable mineral raw material used for many types of commercial production. Fields of the application of clays primarily depend on their mineral composition, which determines the technological properties of raw material. Criteria for estimating the quality of clays include comprehensive data on their physicochemical properties (grain-size composition, color, chemical composition, degree of dispersion, temperature and interval of sintering, and others), mineral composition, and structural-morphological features of clay minerals. It is known, for instance, that the ceramic properties of kaolin products are defined by their degree of dispersion (Maslennikova et al., 2002). The morphology, size, and color of kaolinite particles are of great significance in the filling and coating of paper (Bumdy and Ishley, 1991). Technologically, useful properties of kaolinite can be obtained by synthetic modification of the initial clayey material. However, the same properties can be related to the evolution of natural mineral matter owing to the erosion of weathering crust and the sub- sequent transport, redeposition, and diagenetic trans- formation of sediment. This aspect is especially important from the practical point of view. All these processes are accompanied by the structural-morpho- logical transformations of kaolinite and dispersion of its crystallites. The latter process reflects peculiarities of the lithogenesis of clayey rocks at different stages. Increase in the degree of dispersion and structural dis- ordering of kaolinite depends primarily on the dura- tion of its transport (Gorbachev et al., 1971). New Structural-Morphological Features of Kaolinite from Clayey Rocks Subjected to Different Stages of Lithogenesis: Evidence from the Voronezh Anteclise N. S. Bortnikov a , V. M. Novikov a , A. D. Savko b , N. M. Boeva a , E. A. Zhegallo c , E. B. Bushueva d , A. V. Krainov b , and D. A. Dmitriev b a Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 119017 Russia e-mail: novikov@igem.ru b Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 Russia e-mail: asavko@geol.vsu.ru c Borisyak Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya ul. 123, Moscow, 117997 Russia e-mail: ezheg@paleo.ru d Faculty of Geology, Moscow State University, Moscow, 119991 Russia e-mail: bushe41@mail.ru Received February 15, 2012 Abstract—This paper reports the results of precision structural-morphological study of kaolinite from clayey rocks taken in various areas of the Voronezh anteclise subjected to different stages of lithogenesis: primary kaolins of the weathering crust, proluvial-talus and lacustrine secondary kaolins, as well as lacustrine-swampy fireproof and deltaic-lagoonal refractory clays. The clayey material was transported over more than 300 km. The formation of the fireproof and refractory kaolin deposits in the Voronezh anteclise was related to the Devonian and Early Cretaceous stages of the geological evolution of the region. In terms of spatiotemporal and facies features, the studied genetic series of the kaolin clay deposits is unique. It was established that the sequential structural-morphological evolution o kaolinite in the considered deposits was caused by its mechanical disintegration during transport and redeposition. Interrelation between organic and mineral mat- ters in the fireproof clays was revealed for the first time. Experimental studies of the behavior of kaolinite during sequential grinding and heating confirmed the main reasons for its natural degradation. The formation of virtu- ally monomineral kaolin clays was provoked by the “flow-through” diagenesis, which is similar to weathering in trend. Evolution of mineral matter of the considered genetic series in kaolinite clay deposits was accompanied by the increase of δ 18 O values and their dispersion. Peculiarities identified in the behavior of kaolinite and related oxygen isotope characteristics of different-aged denudation and redeposition products of the Devonian weathering crust can play an indicator role in studying different stages of the lithogenesis of clayey rocks. DOI: 10.1134/S0024490213050039