Prospects of the southwestern part of the Alakit-Markha kimberlite field for the manifestation of kimberlite magmatism: magnetotelluric studies

Abstract

The replenishment of the mineral resource base in the Daldyn-Alakit diamond-bearing region (Yakutia) is associated with the identification of new primary diamond deposits within the Alakit-Markha kimberlite field (AMKF). The development of Paleozoic terrigenous carbonate deposits within the field is complicated by intruded bodies of traps, thus creating a challenging geological task for prospecting. This study aimed to investigate the features of the deep structure of the Earth’s crust, including sedimentary cover, and their relationship with the manifestations of kimberlite magmatism to isolate objects of kimberlite magmatism by geophysical methods in an area with a very complex geological structure. The results of predictive prospecting studies using magnetotelluric sounding (MTS) conducted within the southwestern flank of the AMKF are considered from the standpoint of structural control of the placement of kimberlite fields and their bushes. Our findings show that the main factors controlling the manifestations of kimberlite magmatism at the medium-scale stage, and local studies include conducting inhomogeneities in the Earth’s crust located at the intersection points of the Daldyn-Olenek zone of deep faults with multidirectional tectonic disturbances and low-amplitude depressions complicated by structures of the opposite sign. Similar geological and structural prerequisites were established in the areas of development of kimberlite bodies identified by geological studies within the AMKF. Enhanced by favorable mineralogical and geochemical results, these prerequisites can be considered the main criteria for predicting new kimberlite bodies in a well-studied area. We specified the central part of the studied MTS profile based on the geological, geophysical, mineralogical, and geochemical data, which is the most promising for forecasting and identifying new diamond-bearing objects in the category of individual kimberlite bodies.