CIS-CASPIAN DEPRESSION AND ITS REFLECTION IN GEOPHYSICAL ANOMALIES
The article presents new methodological methods for interpreting geological and geophysical data with the aim of justifying the search for oil and gas in the inner regions of Cis-Caspian depression and confirming the hypothesis of uplifted foundation blocks and large drillable subsalt elevations. The observed gravitational and magnetic anomalies were represented in the form of numerical matrices covering the entire territory of Cis-Caspian depression with 120*100 dimensions of elements for maps of 1:1000000 scale. A total of 40 schemes of geophysical parameters were generated. In the central part, the transformations allowed identifying large, intense anomalies associated with the morphology of the subsalt bed surface. Gravity steps, which limit large anomalies, testify to the steep slopes of structural elements. This is the possible zones of transition from shallow-water conditions to deep-water ones. The inversion of gravitational and magnetic anomalies can be associated with the objects of formation of carbonate rocks of organogenic Genesis of basin, side and shelf types formed on slope areas. Transformed maps of gravitational and magnetic anomalies were calculated for the Caspian basin at different altitudes from 5 to 50 km with a step of 5 km; interval transformed schemes were calculated. As a result of processing and interpretation, the author predicts the existence of an anticline zone in the Central region, within which there is a possible uplift for further growth of large carbonate structures of the Karachaganak type. The zone with the same signs is also registered in the western part of the Central Cis-Caspian depression in the region of Aralsor gravity high.