Analysis of a digital terrain model for solving geological problems by the example of Aktogai ore field

The formation of terrain reflects a combination of geological processes, including tectonics, magmatism, and erosion. A digital terrain model (DTM) is an important tool for solving geological problems, including the prediction of ore deposits, especially in areas of low exploration maturity. The paper discusses the surface imprinting of geological processes that form a terrain, and also considers a method of digital terrain model analysis. The presented method allows identifying specific landforms similar to those formed above known deposits that makes it possible to add one more prospecting criterion when prospecting for porphyry deposits and deposits formed under similar conditions. The Aktogai ore field was selected as the object for studying the terrain above the known deposits. The Aktogai ore field is located in the northeastern part of Near-Balkhash territory. It includes two major porphyry copper deposits, Aktogai and Aidarly, a small copper deposit Kyzylkia, as well as a number of copper and polymetallic occurrences of porphyry and vein types associated with the Koldar granite massif of the "variegated batholith" formation. All objects identified within the Aktogai ore field were formed under specific structural conditions of ore formation and were affected by erosion processes to varying degrees. This, in turn, is expressed by the presence of local landforms of these objects on the day surface, which are characterized by different "terrain energy" factors. Analysis of the DTM surface allows not only to identify local landforms above an ore body and their morphological features, but also to indirectly assess the erosional truncation of the ore body. Based on morphological characteristics, it is also possible to classify host rocks lithological units. An assessment of the applicability of the method depending on the characteristics of an ore body and an indirect assessment of the tectonic conditions of deposit formation are provided. It has been established that large ore deposits (Aktogai, Aidarly, Zapadny Stockwork) manifest themselves in the terrain as local cauldron subsidences. These zones are characterized by a high degree of textural heterogeneity and coincide with areas of intense metasomatism. Areas morphologically and spectrally similar to the areas of known ore bodies have been identified, indicating their potential for further exploration. DTM and textural analysis methods allow identifying geological and structural features associated with porphyry systems and serve as an additional tool for predicting new ore bodies/deposits. The integration of morphometric (physiographic) and spectral analysis increases the reliability of the interpretation of geological processes.