The tectono-paleogeograhic inheritance of barely documented Paleotethyan influence on the Southern Carpathian-Balkan belt is herein reappraised to highlight complex processes occurring along an alternative branched co...The tectono-paleogeograhic inheritance of barely documented Paleotethyan influence on the Southern Carpathian-Balkan belt is herein reappraised to highlight complex processes occurring along an alternative branched configuration of Triassic fossil subduction zone interfaces.The absence of Paleotethyan oceanic accretionary complexes,and the unavailability of rocks returned from poorly traceable Triassic subduction zones allow no conventional insights into its internal structure.In contrast,the adjoining Dinarides and investigated western Southern Carpathian-Balkan belt contain metamorphic rocks ejected from the precursory Late Paleozoic Paleotethyan active margin.An inventory and reappraisal of Variscan and Cimmerian imprints,far-field effects place the peri-Moesian Southern Carpathian-Balkan belt into the overriding plate position above the Triassic Paleotethyan active margin.Ongoing Permian–Early Triassic dragging of underlying Paleotethyan crustal material beneath external segments of the continental margin is contemporaneous with the onset and formation of several episutural back-arc oceans.These include the Maliac Ocean with a here introduced NNW-SSE striking Lower–Middle Triassic marginal shallow-water clastic-carbonate basin of Getic Unit(Gornjak nappe)that is spatially in line with the“Volvi-Therma”western Rhodope aborted Triassic rift system.The carbonate platform deposition was interrupted by a change in the geodynamic regime at the end of the Middle Triassic(inducing mild compressional deformations and the regional uplift resulting in missing of Upper Triassic sediments).The constraints on the investigated sequences yield that the lagged Paleotethyan closure in the Balkan sector occurred during the late Ladinian-Carnian interval.展开更多
The south-east of Cameroon encompasses a wide variety of geological structures among which we can cite the Congo Craton (CC), the Sanaga Fault (SF), the Yaoundé Domain, the Panafrican belt, the Protozoic series a...The south-east of Cameroon encompasses a wide variety of geological structures among which we can cite the Congo Craton (CC), the Sanaga Fault (SF), the Yaoundé Domain, the Panafrican belt, the Protozoic series and the Dja complex. The presence of all these structures justifies the great tectonic activity to which this area was subject from the rupture of Pangea to the creation of the different plates that exist today. In this work, we will bring out a high-resolution structural map of the study area by applying the qualitative analysis of the phase filters on 200,900 points of gravimetric data obtained from the combination of the XGM2016 and ETOPO1 models. Then, with these same data, we will bring out another structural map with the maxima method called Multi-Scale Horizontal Derivative of Vertical Derivative (MSHDVD) which will be compared to the first in order to show the limits of the MSHDVD method. To do this, we will first use the extension method to highlight the map of residual anomalies, then a combination of derivative, gradient and phase filters to highlight the geological structures responsible for fracturing in this area. Phase filters have the advantage that they make it possible to highlight all the geological edges responsible for the fracturing without taking into account the depth, while the MSHDVD method highlights the existing geological contacts (edges) at depths well defined by the examiner. The structural map obtained with the MSHDVD method shows that the major structural direction in this zone is W-E while that obtained from the interpretation of the phase filters is more precise and shows that the major structural direction in this area would be N-S and this result would be in perfect agreement with the tectonics of East Cameroon.展开更多
文摘The tectono-paleogeograhic inheritance of barely documented Paleotethyan influence on the Southern Carpathian-Balkan belt is herein reappraised to highlight complex processes occurring along an alternative branched configuration of Triassic fossil subduction zone interfaces.The absence of Paleotethyan oceanic accretionary complexes,and the unavailability of rocks returned from poorly traceable Triassic subduction zones allow no conventional insights into its internal structure.In contrast,the adjoining Dinarides and investigated western Southern Carpathian-Balkan belt contain metamorphic rocks ejected from the precursory Late Paleozoic Paleotethyan active margin.An inventory and reappraisal of Variscan and Cimmerian imprints,far-field effects place the peri-Moesian Southern Carpathian-Balkan belt into the overriding plate position above the Triassic Paleotethyan active margin.Ongoing Permian–Early Triassic dragging of underlying Paleotethyan crustal material beneath external segments of the continental margin is contemporaneous with the onset and formation of several episutural back-arc oceans.These include the Maliac Ocean with a here introduced NNW-SSE striking Lower–Middle Triassic marginal shallow-water clastic-carbonate basin of Getic Unit(Gornjak nappe)that is spatially in line with the“Volvi-Therma”western Rhodope aborted Triassic rift system.The carbonate platform deposition was interrupted by a change in the geodynamic regime at the end of the Middle Triassic(inducing mild compressional deformations and the regional uplift resulting in missing of Upper Triassic sediments).The constraints on the investigated sequences yield that the lagged Paleotethyan closure in the Balkan sector occurred during the late Ladinian-Carnian interval.
文摘The south-east of Cameroon encompasses a wide variety of geological structures among which we can cite the Congo Craton (CC), the Sanaga Fault (SF), the Yaoundé Domain, the Panafrican belt, the Protozoic series and the Dja complex. The presence of all these structures justifies the great tectonic activity to which this area was subject from the rupture of Pangea to the creation of the different plates that exist today. In this work, we will bring out a high-resolution structural map of the study area by applying the qualitative analysis of the phase filters on 200,900 points of gravimetric data obtained from the combination of the XGM2016 and ETOPO1 models. Then, with these same data, we will bring out another structural map with the maxima method called Multi-Scale Horizontal Derivative of Vertical Derivative (MSHDVD) which will be compared to the first in order to show the limits of the MSHDVD method. To do this, we will first use the extension method to highlight the map of residual anomalies, then a combination of derivative, gradient and phase filters to highlight the geological structures responsible for fracturing in this area. Phase filters have the advantage that they make it possible to highlight all the geological edges responsible for the fracturing without taking into account the depth, while the MSHDVD method highlights the existing geological contacts (edges) at depths well defined by the examiner. The structural map obtained with the MSHDVD method shows that the major structural direction in this zone is W-E while that obtained from the interpretation of the phase filters is more precise and shows that the major structural direction in this area would be N-S and this result would be in perfect agreement with the tectonics of East Cameroon.
