Elisional processes and salt tectonics: Communication 2. Formation mechanism of salt diapirs

The possible role of endogenic factors in the formation of salt deposits and salt diapirs is discussed with emphasis on the sedimentary origin of salts and elisional nature of epigenetic salt bodies. It is shown that dehydration and high solubility of chlorides, density inversion, and high coefficient of linear expansion under heating are the main factors responsible for the growth of salt domes. Elisional processes in clays of subsalt formations exert a considerable impact upon their growth in rock basins. Tectonic processes play an important, although secondary, role in these transformations.     

Distribution and formation conditions of salt diapirs and mud volcanoes

Analysis of the distribution of salt diapirs and mud volcanoes in the Earth’s continental block reveals their frequent spatial coincidence. These structures are also characterized by similar morphological and geological structures indicating their elisional origin. The appearance of zones with anomalously high formation pressures (AHFP) is the main factor responsible for the development of mud volcanoes and salt diapirs. The anomalously high formation pressure reflects transformation of the phase composition of salts, clay minerals, and dispersed organic matter under the influence of thermolysis and thermocatalysis in closed physicochemical systems.     

Facies types of sedimentary iron ore deposits and their geochemical features: Communication 1. Facies groups of sedimentary ores, their lithology, and genesis

Economic significance of the sedimentary iron ore deposits is shown. The most important types of these deposits are characterized and their genesis is considered. Special attention is given to the formation of goethite-chlorite-siderite ooliths, which represent the main component of marine iron ore deposits. Geochemical and mineralogical features of different types of iron ores are examined.     

The biosphere and problems of oil origin

The chemical composition, structure, and biomass of the present-day biosphere are discussed with particular attention paid to reproducibility of organisms. It is shown that the Earth’s stratisphere (sedimentary sphere) contains significant traces of past biospheres, which determines the biogenic oil generation potential. Based on indications of biogenic oil origin and particular examples, some aspects of the sedimentary-migration theory of oil and gas origin are considered.     

Siderite formation and evolution of sedimentary iron ore deposition in the Earth’s history

The role of siderite in Phanerozoic and Precambrian iron formations is discussed. Various types of iron formations are characterized, and their place in the evolution of sedimentary iron ore deposition is outlined. In Precambrian iron ore deposition, siderite is a primary mineral, whereas in Phanerozoic iron formations it becomes a secondary mineral and is commonly related to diagenetic and catagenetic processes.     

Thermobaric Depth Settings of Sedimentary Rock Basins and Their Fluid Dynamics: Communication 3. Superhigh Pressures in the Stratisphere and Salt Diapirs

Lithology and Mineral Resources - The paper addresses regularities in the location and conditions of the formation of salt diapirs. Their formation is attributed to a thick salt “cover”...     

Origin and prospects of the Cimmerian iron ore basin in Ukraine and Russia

The article is dedicated to the geological structure and spatial position of the Cimmerian Kerch-Taman iron ore basin. Based on paleogeographic and recent geochemical data, it is shown that iron accumulated in the Cimmerian brackish lake originated mostly from weathered old rocks of the Ukrainian shield. The metal in question was delivered to the basin by its multistage migration and concentration owing to processes, which involved the eluvial zone of weathering crusts, krasnozem soils, rivers, bogs, and limans surrounding the lake. The formation mechanism of iron ore deposits is considered with the assessment of prospects for the discovery of new Cimmerian deposits in the spacious West Kuban depression and Crimea region and offshore areas of the Azov and Black seas.     

The 100th Birthday of Roman Fedorovich Gekker

Lithology and Mineral Resources -     

Forty Years of the Journal Litologiya i poleznye iskopaemye (Lithology and Mineral Resources) (1963–2003)

Lithology and Mineral Resources -     

Problems of Iron and Phosphorus Geochemistry in the Precambrian

The localization of economic sedimentary iron ore and phosphorite resources is discussed in comparative aspects. It is shown that the major economic resources of iron ore are hosted in Precambrian rocks, whereas the phosphorites are related to Upper Phanerozoic. High-temperature hydrothermal solutions served as an important source of iron for jaspilite ores. The low P₂O₅content therein indicates that the phosphorus deposition was only weakly related to the hydrothermal activity. Thus, the hydrothermal origin of phosphorite is denied from the geochemical standpoint.