scholarly journals The experience of dividing the potential fields of Donbass into background, residual and local components and some results of interpretation

Author(s):  
Д.Б. Давыденко ◽  
С.Г. Парада

Статья посвящена определению оптимальных процедур обработки и разделения потенциальных полей на фоновую, остаточную и локальную составляющие, а также обсуждению некоторых результатов. Актуальность работы определяется необходимостью разработки геофизической основы для минерагенического анализа системы Донецкого складчатого сооружения. Цель исследования. Выбор оптимальных процедур обработки геофизических данных и разделение потенциальных полей на фоновую, остаточную и локальную составляющие, оценка возможности использования полученных результатов для минерагенического анализа Донецкого складчатого сооружения. Методы исследования. Исходными материалами для исследования послужили результаты аэросъемочных работ в цифровом формате, проведенных в 2011 году компанией «Аэрогеофизика» с использованием современных высокоточных приборов. А для приграничной полосы с Украиной – материалы аналоговых аэрогеофизических съемок, проведенных до 2000 г. Подразделение исходных полей на составляющие компоненты проведено с использованием методов математического преобразования исходных данных с использованием отечественного программного комплекса ГИС Интегро. Оценка информативности преобразования комплекса исходных данных решалась с привлечением технологии статистического зондирования геополей COSCAD 3D, а также технологии решения обратной задачи гравиразведки и магниторазведки. Результаты исследования. Разработана технология, обеспечивающая составление сводных карт потенциальных полей с использованием материалов разновысотных аэросъемок на основе отечественной геоинформационной системы ГИС Интегро. Установлены оптимальные процедуры и осуществлено подразделение исходных магнитного и гравитационного полей на региональную, остаточную и локальную компоненты. При выделении локальнй составляющей аномалий магнитного поля впервые для исследуемого района выделены и прослежены протяженные зоны слабоинтенсивных положительных магнитных аномалий. Установлено, что эти аномалии связаны с разломами, приуроченными к осевым плоскостям линейных антиклиналей и отражают увеличение намагниченности горных пород в связи с гидротермально-метасоматическими преобразованиями. Распространение выявленных ранее золоторудных проявлений в существенной мере контролируется вновь обнаруженными зонами слабоинтенсивных магнитных аномалий. Это позволяет придать высокую значимость выделяемых линейных аномальных зон как критериев для решения задач минерагенического районирования The article is devoted to determining the optimal procedures for processing and dividing potential fields into background, residual, and local components, as well as discussing some of the results. The relevance of the work is determined by the need to develop a geophysical basis for the mineralogical analysis of the Donetsk folded structure system. Aim. To select the optimal procedures for processing geophysical data and to divide potential fields into background, residual and local components, to evaluate the possibility of using the results obtained for mineragenic analysis of the Donetsk folded structure. Methods.The initial materials for the study were the results of aerial surveys in digital format conducted in 2011 by the company "Aerogeofizika" using modern high-precision instruments. And for the border strip with Ukraine – the materials of analog aerogeophysical surveys conducted before 2000. The division of the source fields into components was carried out using the methods of mathematical transformation of the source data using the domestic GIS Integro software package. The evaluation of the informativeness of the transformation of the source data complex was solved using the COSCAD 3D statistical sounding of geofields, as well as the technology for solving the inverse problem of gravity and magnetic exploration. Results. A technology has been developed that provides the compilation of summary maps of potential fields using materials from different-altitude aerial surveys based on the domestic GIS Integro geoinformation system. Optimal procedures were established and the initial magnetic and gravitational fields were divided into regional, residual, and local components. When identifying the local component of magnetic field anomalies, extended zones of low-intensity positive magnetic anomalies were identified and traced for the first time in the study area. It is established that these anomalies are associated with faults confined to the axial planes of linear anticlines and reflect an increase in the magnetization of rocks due to hydrothermal-metasomatic transformations. The spread of previously identified gold-ore manifestations is significantly controlled by newly discovered zones of low-intensity magnetic anomalies. This makes it possible to attach high importance to the identified linear anomalous zones as criteria for solving problems of mineragenic zoning

Geophysics ◽  
1977 ◽  
Vol 42 (3) ◽  
pp. 610-622 ◽  
Author(s):  
Chao C. Ku

A computational method, which combines the Gaussian quadrature formula for numerical integration and a cubic spline for interpolation in evaluating the limits of integration, is employed to compute directly the gravity and magnetic anomalies caused by 2-dimensional and 3-dimensional bodies of arbitrary shape and arbitrary magnetic polarization. The mathematics involved in this method is indeed old and well known. Furthermore, the physical concept of the Gaussian quadrature integration leads us back to the old concept of equivalent point masses or equivalent magnetic point dipoles: namely, the gravity or magnetic anomaly due to a body can be evaluated simply by a number of equivalent points which are distributed in the “Gaussian way” within the body. As an illustration, explicit formulas are given for dikes and prisms using 2 × 2 and 2 × 2 × 2 point Gaussian quadrature formulas. The basic limitation in the equivalent‐point method is that the distance between the point of observation and the equivalent points must be larger than the distance between the equivalent points within the body. By using a reasonable number of equivalent points or dividing the body into a number of smaller subbodies, the method might provide a useful alternative for computing in gravity and magnetic methods. The use of a simplified cubic spline enables us to compute the gravity and magnetic anomalies due to bodies of arbitrary shape and arbitrary magnetic polarization with ease and a certain degree of accuracy. This method also appears to be quite attractive for terrain corrections in gravity and possibly in magnetic surveys.


2021 ◽  
Author(s):  
Alexey Shklyaruk ◽  
Kirill Kuznetsov ◽  
David Arutyunyan ◽  
Ivan Lygin

<p>At the stage of small and medium-scale geological and geophysical studies, in addition to seismic exploration, methods of potential fields (gravimetry and magnetometry) are usually actively used. These methods, in contrast to the profile seismic observations, taking into account modern satellite and aviation technologies, provide a high-quality areal density and magnetic characteristics of the study area. The main tasks of modern gravimetry and magnetometry include the task of constructing areal models, contrasting in density and magnetization of surfaces. Among a large number of algorithmic solutions, the most effective are methods using an integrated approach, in which seismic data on the morphology of reflecting horizon is used as a reference.</p><p>Reconstruction of the structural surface morphology by geophysical data can be considered as the problem of finding the relationship between the input information (potential fields, geophysical data, and available a priori information) and the desired surface. To assess the dependence, it is proposed to use the reference plots on which both input and output data are presented. Currently, one of the trends in solving such problems is methods based on neural networks. Neural networks can be of various configurations (feedforward networks, radial-basis function networks, backpropagation networks, convolutional networks, etc.), have a different number of layers and neurons.</p><p>In this research, we consider the test and real-world example. A site with a known position of the sedimentary cover bottom is considered as a test model. To verify and compare the algorithms, the gravity and magnetic effects of the layer are calculated. The gravity and magnetic fields were supplied to the input to the algorithms for constructing regression dependence and training the neural network. An incomplete model of the sedimentary cover was supplied to the input for training neural networks. The task was to restore the missing part. The parameter of the standard deviation of the original and reconstructed model was less than 2% for all types of neural networks.</p><p>As a real model, a site was considered where basement cover is only partially available. It was obtained as a result of seismic interpretation. All available geological and geophysical data were used to reconstruct the horizon. Models obtained using reconstruction algorithms can be additional information for further detailed description of the geological structure.</p><p>It should be noted that since neural networks help to find complex functional relationships between field parameters and attributes of the studied environment, they could be used in the tasks of complex interpretation of geological and geophysical data.</p>


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