Metal deposits in sedimentary rocks are frequently of controversial origin. This being so, any new approach that has bearing on the genesis of ores in sediments is important. Both epigenetic and syngenetic theories have been invoked for most stratabound deposits. Also, the relative importance of normal sedimentary processes and unusual processes, such as volcanogenic exhalations, has been debated at length. Trace- or minor-element studies of most types of metal deposit have been undertaken by a number of geologists with varying success. This paper reviews some of the more recent geochemical work on certain classes of ores in sediments and relates the geochemical data to the prevalent theories of origin of the deposits.  <...>

Numerous detailed studies of stratiform  copper deposits reported in recent years have rejected the classic igneous-hydrothermal epithermal/telethermal origin for such mineralization, and have instead suggested that an origin intimately related to the processes of sedimentation would be much more suited to the observed character of these deposits. Overwhelming features, such as the widespread continuity of mineralization within a sedimentary basin and the distribution of mineralization within narrow stratigraphic limits, are commonly cited as evidence of sedimentary origins. However, such features do not exclude the possibility of diagenetic additions of ore metals to particularly favorable stratigraphic horizons, and in fact recent studies indicate repeatedly that one or more diagenetic events preceded the deposition of ore metals. For example, the deposition of iron sulfides, and in some cases sulfate-bearing minerals, is commonly observed to have occurred before the introduction of ore-stage metals. <...>

The stratiform deposits make up a special group of lead-zinc deposits possessing many common features in which they differ from the similar deposits of other industrial-genetic types.
They are characterized by ores confined to strata of carbonate rocks, most frequently dolomites, by ore bodies of predominantly stratal form represented by impregnation ores of simple mineral composition, within which galena usually predominates over sphalerite (rarely the reverse), by the absence of magmatic rocks of similar age to the ore in the vicinity of the deposits,

В статье охарактеризованы геологические и ассоциирующие с ними рудные формации стратиформных колчеданно-полиметаллических и свинцово-цинковых руд в составе Тунгусикского формационного комплекса. Выделены и описаны рудно-формационные типы месторождений и три типа рудных полей со свинцово-цинковым оруденением в Ангаро-Большепитской зоне.

The investigation of stratiform/stratabound ore deposits associated with sediments and volcanics and ranging in age from Precambrian to Recent, has become a specialized branch within the wider scope of ore petrology. It is, by all means, not an entirely new field of endeavour and it has always had a place in economic geology, but an accelerated shift in both individualized and collective efforts in the study of the stratiform mineral accumulations has resulted in a large amount of dispersed data.

Рассмотрены минералого-геохимические типы стратиформных свинцово-цинковых месторождений в карбонатных толщах: сарданский, миссисипский, силезско-краковский, миргалимсайский, шалкиинский, горевский, барвинский, новоземельский и учкулачский. Охарактеризованы основные особенности состава руд и их минералого-геохимические типы.
Показано, что руды рассматриваемых месторождений характеризуются различным набором и концентрациями сопутствующих элементов в зависимости от региональных условий накопления рудовмещающих карбонатных толщ.

Системное изучение процессов, приводящих к образованию сульфидных залежей цветных металлов в осадочных толщах, относимых к разряду стратиформных, является необходимым звеном как в общей теории рудообразования, так и в концепциях литогенеза. В учении о стратиформных месторождениях одной из актуальных является проблема связи процессов рудо- и литогенеза. Главными остаются вопросы связи вещества вмещающей осадочной толщи с оруденением, устойчивости рудных горизонтов на больших площадях Земли, влияния осадочных фахщй на стратиформную рудоносность пород, а также вопросы влияния постседиментационных преобразований на формирование рудных залежей. Ответы на эти вопросы открывают путь не только к разработке теории генезиса месторождений стратиформного типа, но и к практике их прогноза и успешных поисков. <...>

Практическое руководство по стратиформным месторождениям твердых полезных ископаемых. Часть 4. Принципы и общие исследования. Том 7. Гипергенные и поверхностные рудные месторождения, текстуры и строение

Office de la Recherche Scientifique et Technique, Outre Mer (ORSTOM), Boudy, France
Office de la Recherche Scientifique et Technique, Outre Mer (ORSTOM), Boudy, France

The Republic of South Africa is a metal producer of the first rank. Gold is the most important of the metals and up to the end of 1971, U.S.$ 32 billion had been realized from its sale. This figure was equivalent to 80% of the total value of all metals sold. The gold province is located on the Kaapvaal craton which is composed of Precambrian sedimentary-volcanic and granite-greenstone assemblages ranging in age from 1,750 to 3,500 million years. This craton forms the southern part of the Southern African Shield. No significant gold mineralization has yet been found beyond the boundaries of this shield. On the Kaapvaal craton, five Proterozoic sedimentary-volcanic basins lie on an Archean basement.  <...>

Among the strata-bound ore deposits, the group of sandstone-type, sometimes called red-bed type, forms a complex case of genetic problems related to the detrital1 nature of the ore-bearing facies. The group of the so-called red-bed deposits appears to be homogeneous, even if some transitions are frequent, both towards volcano—sedimentary deposits and towards Kupferschiefer2.