The aim of this study is to improve the structural map of Douala-Kribi basin. For this purpose, computer tools are used to make qualitative and quantitative analyses to interpret the gravity data. The findings provided several maps which are: the Bouguer gravity anomalies, residual, horizontal gradient, analytical signal, tilt angle, variation of depth, and multi-scale analysis gravity anomalies maps. A thorough examination of these maps highlights lineaments interpreted as faults, and intrusive bodies in the study area. The multi-scale analysis helped to portray the deep faults and therefore construct the structural map of the Douala-Kribi basin. The application of the Euler deconvolution method and variation of the maxima solutions of horizontal gradient upward continuation (HGup) have resulted in the depth of the structures and the intrusive bodies. The faults identified in the Douala-Kribi basin seem to be induced by tectonic movements in addition to the uprise of intrusion. The Euler solutions and tilt angle depths are included in those of the residual field while those from the analytical signal partly overlap those from the residual field and tilt angle. Then, the Euler solutions maps, and the maxima solutions contribute to highlighting the trust interval depth which is the compatibility depth.
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Isla Socorro is an oceanic island located in the Eastern Pacific Ocean, at the junction of the Clarion Fracture Zone and Mathematician Ridge, approximately 600 km west of the Mexican coastline. Very little is known about the submarine portion of the island, but based on the oldest subaerial deposits, it is inferred to be primarily a basaltic shield cone. In this study, the subsurface structure of Isla Socorro was analysed based on an integration of geological and geophysical data. The geophysical data consist of high-resolution airborne magnetic data as well as an integration of terrestrial gravity and high-resolution satellite gravity. The study revealed important information about the composition, structure and origin of the volcanic edifice. The analysis and interpretation of the gravity and magnetic data indicate the existence of extensional systems associated to the principal tectonic structures of the Revillagigedo area. The horizontal gradient and Euler deconvolution of magnetic data reveal the presence of curved features interpreted as caldera structures. A central, vertically extensive body low in both density and magnetic susceptibility was identified through the 2D forward and 3D inverse modelling techniques. This body could represent a high-temperature zone above the Curie point, thus, we propose this body as a remnant magma reservoir and the source of the most recent volcanic activity from subaerial Socorro, and indicates that the possibility of a future large volume eruption from the summit cannot be ruled out.
Authorial comprehensive comments and explanations are given to some of the interpretations applied in the tectonic part of the newly published Geological Atlas of Poland (Nawrocki, Becker, 2017) that considerably change the hitherto generally accepted concepts. It should be, however, admitted that most of those "new’" solutions were already proposed in the past by other workers as hypotheses that could not have been tested in the then state of knowledge on Poland’s deep geology and scientific tools at hand. This has now changed with abundant new data obtained with modern seismic techniques and advanced methods of potential field modelling. Using those data, we justify the reasons for, among others, a significant eastward shifting the front of the Variscan Orogen in Poland andfor the accompanying change in position of the division line between the Precambrian and Palaeozoic platforms. We also show the rationale for accepting a far-reaching southwestward extent of the East European Craton’s crystalline basement below the Palaeozoic Platform and for reinterpretation of the Teisseyre-Tornquist Zone’s nature, together with the question of early Palaeozoic terranes in the TESZ and the situation of the Caledonian foredeep at the SW margin of the East-European Craton.
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