Structural control of volcanic ore deposits in the context of global tectonics

Structural control of the deposition of endogenic ores, among which the ores of volcanic affinity play an important role, has been studied by the author in several regions of four continents. Correlation of the results has revealed that generally there is a repetition of four sets of ore-controlling basement fracture zones. All the four sets of basement fracture zones are not always well developed in the sub-surface level and in the morphology of a region, and some of them usually play a dominant role depending on the geological development of the territory (Table 1). The strike of the ore-controlling basement fractures and their distribution have shown similarities with the pattern of fractures distribution in the floor of the adjoining oceans in three of the studied areas. The most important feature is the joint development of east-west trending fracture zones in both the oceanic areas and the basement of continental areas. One of these zones, defined as the «Fourty-north Fracture Zone » has been traced for a considerable distance on a global scale, the Mendocino fracture zone being considered as its prolongation. The results do not exclude the possibility of a continental drift in some areas, but require the presence of a rigid layer with a rather uniform global fracture pattern existing in the period before rifting and drifting apart of the plates.