ON THE IMPROVEMENT OF THE CATAGENESIS SCHEME OF THE LOWER – MIDDLE JURASSIC DEPOSITS OF THE URENGOY PETROLEUM REGION AND ADJACENT TERRITORIES BASED ON MINERAL AND STRUCTURAL INDICATORS

The article briefly describes the state of the problem concerning stages and zoning of the catagenesis of terrigenous sedimentary strata, examines the mineral and structural indicators of the stages of regional catagenesis determined by a number of researchers in various petroleum basins of the world. Taking into account the mineral and structural indicators of the organic matter (OM) catagenesis scheme by S.G.Neruchev, N.B.Wassoevich and N.V.Lopatin, as well as the catagenesis scheme of terrigenous rocks by N.V.Logvinenko and L.V.Orlova, the author has compiled a more detailed scheme of stages and phases of regional catagenesis of the Lower-Middle Jurassic deposits of the Urengoy petroleum region and adjacent territories of the West Siberian sedimentary megabasin. To distinguish the stages and phases of catagenesis, the composition and typomorphic features of authigenic clay and carbonate minerals, feldspar, silica minerals and some other secondary minerals were used. In the sediments of the Lower-Middle Jurassic, according to the complex of mineral and structural criteria, three stages of rock transformation have been established: middle, late catagenesis and early metagenesis, as well as the main phases of identified stages. Minerals are characterized as indicators of boundaries between stages of middle and late catagenesis, late catagenesis and early metagenesis, as well as boundaries between phases of each stage.