Formation of prospecting criteria for copper-porphyry deposits based on the construction of reference models

Abstract

Purpose. To study the modern methodology for forming a list of mineragenic factors and prospecting signs of ore fields and deposits of copper-porphyry type based on reference objects and model constructions on the example of deposits of Jungar-Balkhash folded region. Methodology. The methodology for identifying the desired factors and criteria is based on the collection and analysis of published and historical data, formation of digital databases using raster and vector geological maps. It also includes the use of modern, advanced specialized technologies and software packages for geophysical surveys and remote sensing data. According to the adopted technology, the results of aerospace methods are used, which include aerial photography, space radar imaging, infrared and spectrozonal surveys and others. The research involves interpretation of WorldView-3 satellite images. Findings. A list of metallogenic characteristics describing potential copper-porphyry mineralization within the study area has been compiled. Using the Spectral Evolution PSM-3500 infrared spectrometer, characteristic areas of secondary changes in copper-porphyry systems have been identified. ASTER spectral satellite radiometer data have identified mineral spectra, iron hydroxides, propylitic associations, areas of quartzite formation and silicification. By interpreting WorldView-3 satellite images, digital files have been obtained identifying iron ore minerals (hematite, goethite), secondary quartzites (advanced argillizites), varieties of sericite and other clay minerals, silicon, carbonates and propylites (chlorite, epidote). Based on interpretation, “parquet” fracturing in granite bodies and in the area of volcanogenic and sedimentary strata development has been identified, as well as structural lines indicating the strike of rock layers. Originality. Using the example of an exploration area based on the analysis of a priori and up-to-date data, the nature of a set of relevant criteria and signs for predicting and prospecting has been determined, aimed at increasing the reliability and accuracy of formation of geological-geophysical models. Practical value. The collected and systematized geophysical data can serve as a basis for developing plans for further geological exploration, identifying promising areas, determining the required volumes and methods of geophysical surveys. They can also contribute to the increase in estimate of reserves and production at mining sites. The prepared models are intended for preliminary assessment of known and newly discovered ore deposits of various types, as well as for determining the directions of geological exploration in the areas of prospecting the Northern Pribalkhash.