Model of the deep structure of the earth’s crust and upper mantle in the area of the Karymshinskiy gold- ore cluster according geophysical data (south Kamchatka)

Abstract

In the South of Kamchatka, modern geodynamic processes are actively taking place. A deep geological and geophysical model of the structure of the earth’s crust and upper mantle along the regional profile of the Apacha Village -Mutnaya Bay in the zone of Tolmachevsky active magmatic center (TAMC) is presented. The profile passes near the South-Western border of the Karymshinskaya volcano-tectonic structure (VTS) and crosses the Ahomtenskaya VTS. The model created on the basis of integrated interpretation of materials of the earthquake converted-wave method (ECWM), gravity and magnetotelluric sounding (MTS). The thickness of the earth’s crust along the profile varies from 30-33 km at the edges reaching 44-46 km, in its Central part. The dominant feature of the model is a high-density formation – a block of the earth’s crust, saturated with intrusions of the main and ultrabasic composition. The formation of the block is associated with a permeable zone between the crust and the upper mantle. In the block correlation of seismic boundaries is disturbed and in a density model the area with massive heterogeneity is allocated. A significant increase in depth to the M-Boundary in the center of the model is explained by the presence of a “bloated” transition layer between bark and mantle in this place. The thickness of the layer is about 10 km, and the density of the mantle reaches 3,4 g/cm3. It is supposed that it is a site of eklogization of breeds in a zone of paleosubduction of oceanic lithosphere under a continental. The area is favorable for the accumulation of meteor waters, which are in contact with high-temperature environment and postmagmatic solutions of intrusions, which leads to the formation of hydrothermal systems. The genetic connection of Karymshinsky gold- ore cluster with the intrusive array of medium-sour composition, allocated in the zone of the Tolmachevsky active Magmatic Center is shown.

Keywords

• crust
• upper mantle
• transition layer
• deep model
• heat flow
• ecwm
• mtz
• south kamchatka