Issues of subduction of the Maksyutov Eclogite-blueschist Complex (Southern Urals)

Two new geodynamic concepts are considered on the example of the Maksyutov eclogite-blueschist complex (MC), Southern Urals, for their use as global schemes for the origin and development of subduction of eclogite complexes. One of them - the " Subduction Initiation Rule” (SI), represents the process of subduction initiation in pre-arc basins in conjunction with the formation of ophiolite complexes and the formation of a diagnostic magmatic chemostratigraphic sequence of rocks with a certain change in the content of high-charge (HFSE) and lithophile (LILE) elements. The second is the geodynamic classification of oceanic basalts, which make it possible, based on their geochemical characteristics, to consider large structural fragments of the Earth's crust as participants in the subduction process, to determine their magma-generating role as a source of the initial mantle-crustal material, and to evaluate the geochemical interaction between them and with the mantle substrate. The Maksyutov complex is considered a unique facility for testing such developments as general models of formation and development of subduction processes, since the main features and criteria of the SI are presented quite fully and clearly implemented. However, the individual features of the Maksyutov complex - geochemical, petrological and geodynamic - complicate the perception of the SI Rules as a universal model, raising a number of controversial issues related more likely to the features of the orogen, than to the general SI criteria. It is assumed that these features do not affect the established subduction rules, but require further study and clarification, since they affect the established rules of subduction, but require further study and refinement, since they affect the fundamental points of complex formation. These are the questions of the time of origin and duration of the existence of MC, the subduction polarity of its development, the features of the evolution of metamorphism of immersion and exhumation, the source and origin of the UHP index minerals - diamond, etc.