http://localhost:8080/tede/handle/tede/4 2026-11-13T08:56:45Z http://localhost:8080/tede/handle/tede/238 “INTERPRETAÇÃO DE DADOS MAGNÉTICOS SOBRE CROSTA OCEÂNICA EM BAIXAS LATITUDES” Raimundo Oscar de Sousa Junior, Raimundo Oscar de Sousa Junior Vanderlei Coelho Oliveira Junior , Vanderlei Coelho Oliveira Junior This study implemented and validated a space-domain inversion methodology for estimating the distribution of apparent magnetic susceptibility in oceanic crust, specifically designed for interpreting magnetic data in low-latitude regions where conventional Fourier-domain techniques, such as reduction to the pole, suffer from numerical instabilities. The interpretive model consists of a layer of horizontally juxtaposed rectangular prisms with purely induced magnetization and isotropic susceptibility. The inverse problem formulation combines first-order Tikhonov reg- ularization with a positivity constraint, with the purpose of imposing physically plausible bounds on the estimated solutions.The methodology was tested on eight synthetic scenarios organized into three progressive groups that assessed: (i) the stabilizing role of the positivity constraint; (ii) the effect of irregular observation distributions on inversion quality; (iii) the influence of secular variations in the main geomagnetic field (IGRF) when combining surveys from different epochs; and (iv) performance under models with realistic geometry and variable crustal thickness. The tests demonstrated that positivity enforcement is the primary stabilizing mechanism of the inversion, producing geologically more coherent solutions at the cost of a slightly higher data misfit.For the real-data application, the methodology was applied to the São Paulo Transform Fault System (SPTFS) using magnetic data from the NCEI surveys (1966 to 1983) and the COLMEIA expedition (2013). Joint inversion of both datasets revealed limitations arising from the spatial heterogeneity of the NCEI surveys, with a residual standard deviation of 2.51 nT. Restricting the inversion to COLMEIA data alone reduced the standard deviation to 0.02 nT. The COLMEIA-only inversion identified zones of elevated magnetic susceptibility within the intra-transform segments, interpreted as possible occurrences of basalt, gabbro, mylonite, and peridotite, showing good correlation with dredge samples and lithological interpretations from previous studies.The results contribute to the understanding of crustal and upper mantle structure in the equatorial Atlantic, with particular emphasis on the geophysical characterization of serpentinization zones associated with transform faults and distinct mantle exhumation mechanisms (transpression and detachment faulting). Observatorio Nacional Dissertação 2026-06-02T00:00:00Z http://localhost:8080/tede/handle/tede/237 “ANÁLISE DE SÉRIES TEMPORAIS DE TERREMOTOS GLOBAIS A PARTIR DE ESTUDOS ESTATÍSTICOS DE REDES COMPLEXAS DE INTERAÇÕES” Paloma de Freitas Ferreira, Paloma de Freitas Ferreira Douglas Santos Rodrigues Ferreira , Douglas Santos Rodrigues Ferreira Earthquakes are one of the most notable natural phenomena that can be classified as complex systems. These phenomena are unpredictable and potentially destructived can cause great human and economic losses. Seismological events are classified as complex systems due to a series of properties they exhibit. These characteristics manifest themselves, for example, in the form of long-range spatio-temporal correlations, power law distributions, the presence of criticality, and the emergence of non-linear patterns. In this project, seismological events will be studied from the point of view of Statistical Physics, especially through the use of complex network theory and Non-Extensive Statistical Mechanics (NSEM). As previous work has shown, these tools have proved effective in geophysical studies. Thus statistical analysis of global earthquake time series will be carried out in order to determine metrics that serve as criteria for creating correlation networks between seismological events. Dynamic and topological parameters of the networks will be calculated in order to obtain not only how the earthquake series evolves, but also how they relate to each other. The results obtained for these networks will be compared with results using existing models in current literature, such as the successive connections model and the time window method. These results will also allow us to infer correlation properties between earthquake locations. In this way, we hope to contribute to a more complete understanding of the dynamics that govern seismological events, as well as their spatio-temporal correlations, highlighting the importance of a global analysis of events, and not just a local or regional one. Observatorio Nacional Dissertação 2026-05-29T00:00:00Z http://localhost:8080/tede/handle/tede/236 “CARACTERIZAÇÃO MAGNÉTICA E MINERALÓGICA DE AEROSSÓIS ATMOSFÉRICOS EM VOLTA RENDONDA, RIO DE JANEIRO” Mariana Reis Regado, Mariana Reis Regado Plinio Francisco Jaqueto , Plinio Francisco Jaqueto "Exposure to iron-rich particulate matter (PM) has been associated with increased risks of cardiovascular, respiratory,and neurological diseases, underscoring the need for robust tools to characterize pollutant sources and properties inindustrial urban environments. Environmental magnetism provides a rapid and sensitive approach to identify iron-bearing phases and constrain their grain size distribution and oxidation state. Particulate matter was investigated in Volta Redonda city (Southeastern Brazil), a steel-producing city historicallylinked to Companhia Siderúrgica Nacional. Samples were collected from public trash cans, bus shelters, and roadsidesurfaces at distances up to 3 km from the steelworks. Magnetic susceptibility, anhysteretic and isothermal remanentmagnetizations, hysteresis loops, first-order reversal curves, and low-temperature experiments were conducted todetermine magnetic concentration, mineralogy, and domain state. All samples exhibit a consistent magnetic assemblage dominated by hematite, but also stoichiometric and partiallyoxidized magnetite. The low-coercivity fraction spans superparamagnetic (few nm), single-domain, vortex/pseudo-single-domain, and multidomain grains (few microns). No statistically significant differences were detected amongsample types or as a function of distance, indicating a spatially pervasive iron oxide source across the study area. These results demonstrate the utility of magnetic parameters for tracing industrial emissions and provide quantitativesupport for environmental monitoring and risk assessment in steel-producing regions." Observatorio Nacional Dissertação 2026-03-12T00:00:00Z http://localhost:8080/tede/handle/tede/235 “ORBITAL RECORDS SHAPED BY DEPOSITIONAL ARCHITECTURE IN A CONTINENTAL MARGIN: CYCLOSTRATIGRAPHIC–SEISMIC ANALYSIS OF THE MIOCENE ALBACORA OILFIELD (CAMPOS BASIN, BRAZIL)” Mariana Aragão Fernandes, Mariana Aragão Fernandes Daniel Ribeiro Franco, Daniel Ribeiro Franco This master's dissertation aims to integrate cyclostratigraphy and seismic stratigraphy, together with Integrated Prediction Error Filter Analysis (INPEFA) and the Relative Geological Time (RGT) model, to investigate Miocene deposits in the Albacora Oilfield, Campos Basin, Brazil. Well-log gamma-ray data from six wells, distributed along two dip sections and one strike section, were used as paleoclimatic proxies through spectral analysis to identify periodic components related to Milankovitch cycles. Additionally, 3D seismic data acquired over the Miocene deposits of the Albacora oilfield were used to construct geological sections and to analyze the evolution of the depositional system. Cyclostratigraphic analysis revealed clear evidence of orbital forcing within the records. Spectral and evolutionary harmonic analyses allowed the identification of cycles interpreted as long and short eccentricity, obliquity and precession, most of which exceed the 95–99% confidence levels, consistent with expected orbital ratios for 14 Ma, with long- and short-eccentricity wavelengths of ~145 m and ~47 m. Results from correlation coefficient (COCO) and evolutionary correlation coefficient (eCOCO) analyses confirmed the presence of orbital forcing and indicated maximum sedimentation rates ranging from 30.0 to 45.4 cm/kyr across the wells, consistent with previously reported values (~30 cm/kyr) for the same region. Seismic stratigraphic analysis reveals a mainly progradational system, with better stratigraphic preservation in the mid-slope domain, where thicker successions and up to three long-eccentricity cycles are recorded, in contrast to only one cycle on the shelf and at the base of the slope. These variations in stratigraphic preservation, reflected in differences in the number of long-eccentricity cycles identified along dip-oriented seismic sections, demonstrate that seismic-supported multi-well correlation is a useful tool for assessing stratigraphic completeness and, consequently, for improving 2D/3D cyclostratigraphic correlation. Hypotheses involving discontinuous sedimentation and/or depositional hiatuses associated with erosional processes were explored to account for the absence of these records in the shelf and base-of-slope settings. The RGT model corroborates a progradational pattern and reveals variability in sedimentation rates along strike sectrion, whereas INPEFA delineates key stratigraphic surfaces linked to hiatuses and erosional events. These findings underscore the need to account for depositional system dynamics when interpreting cyclostratigraphic signals and refining geological time estimates. Estimates of depositional duration accounting with variations in stratigraphic preservation were compared with biostratigraphic constraints, reshaping previous estimates of depositional duration. To our knowledge, this study provides the first systematic investigation of the lateral preservation of astronomical cyclicity within a seismic volume as controlled by depositional architecture, and demonstrates how incorporating this variability can substantially modify geological time estimates. Observatorio Nacional Dissertação 2026-05-27T00:00:00Z