Interpretation Of Anomalies Research Articles

Identification of Subsurface Geological Structures from Gravity Data by Modelling Techniques in Kalak-Bardarash Area, West of Erbil City Iraqi Kurdistan Region

A quantitative interpretation of gravity anomalies in the Kalak-Bardarash area, west of Erbil City in the Kurdistan Region of Iraq, was performed using two-dimensional analysis techniques. These techniques modeled geological structures identified from a previously created Bouguer anomaly map of the area. Five profiles were selected for the analysis, resulting in eight models constructed for both deep and shallow-seated rock units. The deep-seated rocks are represented by the basement rocks, with models constructed in the NNE-SSW, WNW-ESE, and NW-SE directions using the regional anomaly component. The depth of the basement rocks ranges from five to nine kilometers and is affected by numerous faults in the form of graben and step structures. The basement rock surface slopes towards the NE and ESE at a gradient of 110 m/km. The shallow-seated rocks are represented by the sedimentary cover, which includes Neogene, Paleogene, and Cretaceous-aged groups of formations. The residual component of the anomalies of the five profiles were interpreted. Three profiles, oriented NNE-SSW and nearly perpendicular to the main anticlinal structure, revealed that the Bardarash anticline is influenced by two faults striking both limbs and extending in the NNW-SSE direction, with an estimated throw of 200 meters on each side. The southern fault is believed to extend down to the basement rocks. The other two profiles, oriented NW-SE and nearly perpendicular to the Zab River, indicated the presence of two additional faults with a throw of approximately 600 meters in the deeper parts striking the basement rocks, dipping towards the southeast. The throw of these faults gradually decreases upward in the sedimentary cover, reaching about 200 meters. These faults directly influence the course of the Zab River, directing it in a NE-SW direction at this district.

Three-dimensional quasi-complete information numerical simulation of gravity anomalies and Parallel Computing on CPU-GPU

Abstract In order to improve the efficiency and accuracy of numerical simulation of gravity anomalies in large-scale complex models, this paper proposes a method for three-dimensional numerical simulation of gravity anomalies under arbitrary terrain, and implements its CPU-GPU parallel acceleration scheme. By performing a two-dimensional Fourier transform along the horizontal direction, three-dimensional partial differential satisfied by gravitational potential are transformed into one-dimensional ordinary differential equations in different wavenumbers, reducing computational and storage requirements. Moreover, the ordinary differential equations in different wavenumbers are independent of each other and have good parallelism. By retaining the vertical direction as the spatial domain and introducing traveling wave decomposition, the effects caused by upper and lower boundaries are eliminated. The vertical grid is arbitrary. A two-dimensional quasi-complete information Fourier transform is utilized to enhance both the accuracy and efficiency of the Fourier transform process, allowing both uniform and non-uniform flexible sampling. Based on the high parallelism, one-dimensional ordinary differential equations are solved in parallel using CPU, and quasi-complete information Fourier transform are computed in parallel using GPU. An abnormal sphere is designed to analyze the wavenumber spectral distribution characteristics of the anomalous potential and summarize the wavenumber sampling rules. The logarithmic uniform sampling in the wavenumber domain has high accuracy. Compared with Gauss-FFT, the quasi-complete information Fourier transform selects fewer wavenumbers and exhibits higher accuracy. The computational efficiency is greatly enhanced through the use of single-precision CPU-GPU parallel scheme, and a model with tens of millions of nodes only takes a few seconds. Two terrain models are designed to verify the algorithm's adaptability to arbitrary complex terrains. This is significant for achieving fine inversion imaging and interpretation of gravity anomalies under large-scale complex conditions.

Solving Inverse Magnetometry Problems Using Fuzzy Logic

Integration interpretation of geophysical anomalies is a procedure for extracting geological and geophysical information about the object under study from observed physical fields. Interpretations are closely related to solutions of systems of linear algebraic equations (SLAE), therefore the possibility of the most complete and constructive description of all solutions of SLAE is of particular importance. It will allow you to take into account all additional information about the object and obtain the highest quality interpretation. The paper presents the authors’ results on the constructive description of SLAE solutions and its application to the construction of gravimetric interpretations.

Influence of Bust Size and Waist Circumference on Electrocardiographic Left Ventricular Voltage Index in Blacks Africans

Background: Several studies have investigated on relationship between anthropometric characteristics andelectrocardiographic left ventricular mass (LVM). These studies, performed mainly in Caucasians, have mostlyfocused on influence of body mass index on left ventricular voltage indices (LVVI), and rarely on bust size and/or waist circumference.Aim: To determine influence of bust size and waist circumference on LVVI in healthy sedentary people of blackAfrican origin.Method: Experimental, prospective, cross-sectional descriptive study including 66 volunteers (20 women) aged 18to 35 years. They were received in morning on empty stomach. Bust size and waist circumference were measuredwith tape measure. Standard electrocardiogram was performed at rest. R and S wave amplitude and QRScomplex duration were measured. Sokolow-Lyon, R in aVL, Cornell and Cornell product indexes were calculated.Correlation was sought between each LVVI and anthropometric characteristics studied.Results: Bust size and waist circumference were positively correlated with LVVI. Correlation with bust size wasstatistically significant for all LVVI except for R in aVL index, while for waist circumference it was only significantwith R in aVL index.Conclusion: This study confirms relationship between anthropometric characteristics and LVVI. Therefore,interpretation of LVM anomalies from LVVI should also take into consideration morphotype of each individual.

Litho-structural interpretation of aeromagnetic anomalies reveals potential for mineral exploration in Tizi n'Test Region, Western High Atlas, Morocco

This study interprets aeromagnetic data from the Tizi n'Test area in the High Atlas massif of Morocco, aiming to gain insights into its litho-structural architecture and implications for mineral exploration and mining. We employed six different analytical techniques to the residual magnetic field data, including reduction to the pole (RTP), upward continuation, total horizontal derivative, Tilt angle, Centre for Exploration Targeting (CET) analysis, and Euler deconvolution. Our analyses differentiated the study area into three magnetic domains: the eastern Ouzellarh block, characterized by positive anomalies, a central domain characterized by a negative magnetic signature demarcating the transitional zone between the Anti-Atlas and the High Atlas separated by the Ouchden fault: and the western domain, represented by the Tichka massif. The application of total horizontal derivative, tilt angle, and a combination of filters in ternary image formats (Tilt angle, upward continuation 1000 + Tilt angle and upward continuation 3000 + Tilt angle) revealed both known and previously unidentified geological lineaments, mapping structural complexity across various orientations (NE–SW, NNE–SSE, E–W, NW–SE, and N–S). The CET grid analysis method unveiled the structural complexity, highlighting the geodynamic evolution of the region. Particularly, the Ouchden fault delineates a magnetic domain divide between the ancient High Atlas and the Ouzellarh block (Anti-Atlas). Furthermore, Euler deconvolution indicated magnetic source depths ranging from 52 m in the western domain of the Tichka massif to 6560 m in the Ouzellarh block. A comprehensive structural scheme, classified by C-A fractal analysis, identified zones favourable for exploration and mining, particularly along the Ouchden fault, Tizi n'Test, NE-SW trending lineaments in the northwestern domain, as well as along the Tichka granite’s margin.

On the anomaly interpretation of amplitudes in self-dual Yang-Mills and gravity

We investigate the integrability anomalies arising in the self-dual sectors of gravity and Yang-Mills theory, focusing on their connection to both the chiral anomaly and the trace anomaly. The anomalies in the self-dual sectors generate the one-loop all-plus amplitudes of gravitons and gluons, and have recently been studied via twistor constructions. On the one hand, we show how they can be interpreted as an anomaly of the chiral U(1) electric-magnetic-type duality in the self-dual sectors. We also note the similarity, for the usual fermionic chiral anomaly, between the 4D setting of self-dual Yang-Mills and the 2D setting of the Schwinger model. On the other hand, the anomalies in the self-dual theories also resemble the trace anomaly, sharing the same type of non-local effective action. We highlight the role of a Weyl-covariant fourth-order differential operator familiar from the trace anomaly literature, which (i) explains the conformal properties of the one-loop amplitudes, and (ii) indicates how this story may be extended to non-trivial spacetime backgrounds, e.g. with a cosmological constant. Moving beyond the self-dual sectors, and focusing on the gravity case, we comment on an intriguing connection to the two-loop ultraviolet divergence of pure gravity, whereby cancelling the anomaly at one-loop eliminates the two-loop divergence for the simplest helicity amplitudes.

Strain waves on additively manufactured plates for an on-orbit impact detector concept

Orbital debris impacts on spacecraft are an emerging threat to space missions due to the exponential increase in the number of satellites orbiting the Earth. Debris characteristics (size, material, velocity, etc.) are not well known for the size range of 10 mm or less that is undetectable using Earth telescopes or radar observation. The objective of this research was to determine wether a concept designed to detect impact of particles in the ∼1 to 5 mm range, find the location of the impact, and characterize the impacting projectile (velocity, size, angle, density), is feasible.The paper describes the design, fabrication, and tests performed on “witness plates” (the concept) made of two parallel layers of additively manufactured aluminum and instrumented with sixteen gages, eight on each layer. Laboratory experiments have shown that the waves can be recorded and properly interpreted to find location of impact, sound speed in the plate, and to estimate impact velocity. It was shown analytically that the amplitude of the first strain wave that propagates from the impact point is expected to decay as 1/r. This was observed as well in the signals recorded in the experiments. CTH computations were performed during the pre-test design phase and the post-test analysis phase. In fact, the numerical simulations have been key and pervasive in this research effort as they provided invaluable insight for the initial design and the correct interpretation of signal anomalies seen during the tests. Additionally, the computations confirmed the 1/r law derived analytically, i.e. that the assumptions for the derivation were justified. The main conclusions of the research are that, for a normal impact, the 1/r law for front gages can be easily used to determine the diameter of the impactor. It is possible that the back gages could be used to determine the density of the impactor as well. Finally, it was shown that oblique impacts generate an expected assymetry in the signals recorded. Though this aspect should be investigated further, the assymetry is probably uniquely related to the impact angle, which could provide the angle information.

A new technique based on the eigenvalue of the curvature tensor for enhancing gravity data

Enhancement of the boundaries of geologic structures is one of the main goals in interpretation of gravity anomalies. A range of different algorithms based on field derivatives has been introduced to solve this problem. Among these algorithms, the curvature gravity gradient tensor and its modifications are widely used in enhancing gravity data. These algorithms, however, have some main limitations such as the estimated edges are not compatible with the actual edges or bringing false information. In this study, I introduce a new technique based on the eigenvalue of the curvature tensor. The robustness of the presented technique is exemplified using model studies and a real-world dataset of the Vredefort dome (South Africa). The model studies show that the proposed filter can provide more accurate results and avoid artifacts in the output map. The real application result shows a good correlation between the edges highlighted by the presented algorithm and ring structures in the dome.

Hunger Games Search for the elucidation of gravity anomalies with application to geothermal energy investigations and volcanic activity studies

Abstract Recent metaheuristic approaches are extensively and intensively being implemented to the interpretation of gravity anomalies due to their superior advantages. We emphasize the application of Hunger Games Search (HGS), a newly established metaheuristic inspired by hunger-driven instincts and behavioral choices of animals, to elucidate gravity data for geothermal energy exploration and volcanic activity study. After recognizing the modal features of the objective function tailored and tuning the algorithm control parameters involved, HGS has been trial-tested on simulated data sets of different scenarios and finally experienced in two field cases from India and Japan. Notably, a second moving average strategy has been successfully integrated into the objective function to eradicate the regional component from observed responses. Post-inversion uncertainty appraisal tests have been further implemented to comprehend the reliability of solutions obtained. The solutions retrieved by HGS have been unbiasedly compared in terms of convergence rate, accuracy, stability, and robustness with the solutions of the commonly used particle swarm optimization algorithm. Based on the results accessed, the theoretical and field cases presented could be recuperated more precisely, stably, robustly, and coherently with the available geophysical, geological, and borehole verification, as HGS is able to better explore the model space without compromising its capability to efficiently approach the global minimum. This novel global optimization method can thus be considered as a promising tool in geothermal energy investigations and the study of volcanic activities.

Gravity profiles interpretation applying a metaheuristic particle optimization algorithm of mineralized bodies resembled by finite elements

The interpretation of gravity anomalies is crucial for identifying subsurface mineralized targets and understanding the density variations between the targets and the surrounding structures. To confirm the presence of ore and mineral targets, simple geometric bodies are often used. One of the commonly used global metaheuristic algorithms for gravity data analysis is the particle optimization algorithm. In this study, we employed this method to determine the parameters of buried bodies that resemble finite vertical cylinders by inferring gravity anomalies profiles (amplitude coefficient, depth to top, depth to bottom, origin, and length of the target representing the difference between two depths). The algorithm utilizes particle movement to identify the best way to reach the global or optimum solution. The algorithm's performance was evaluated on synthetic-examples with and without noise (5 % and 10 % levels) and also verified on a real dataset for mineral exploration from Canada. The results showed that the algorithm's stability and accuracy were not affected by the presence of noise and multi-models. Moreover, the field case results were consistent with the existing geological information, borehole data, and previously published outcomes.

Verification of Geophysical Surveys by New Archaeological Excavations on the Grounds of the Middle La Tène Site of Němčice in 2021–2022

The Němčice site located in a strategic area of an agricultural plateau represents one of the most important archaeological sites in Moravia. Non-destructive archaeological surveys including a largescale magnetometer survey, field artefact collections, and metal detector surveys have been carried out there repeatedly over the past two decades. New archaeological excavations during a new project were focused on selected areas and situations identified during magnetometer prospection. The results of an archaeological investigation of the site using test pits confirmed settlement, glass-making and ritual activity under magnetic anomalies at the site. The new possibility of comparing uncovered sunken features and distributions of magnetic anomalies provided new feedback for a more precise interpretation of similar anomalies from magnetograms. An additional detailed apparent magnetic susceptibility measurement in situ showed another possibility for the application of the geophysical method during archaeological excavations. We were able to obtain additional information about the fills or possible post-depositional processes of various sunken features in the case of vertical profiles monitored by magnetic susceptibility meter measurements. The use and combination of various geophysical data has been beneficial in the case of an archaeological site as important as Němčice, and will continue to be so in future archaeological research of the site.

Gravity Field Numerical Analysis and Depth Structure of the South-Eastren Caucasus

In this paper, the gravity anomalies of the Bouguer of the Absheron, Shamakhi-Gobustan and Pricaspian-Guba oil- and gas-bearing regions are interpreted by the 3D prism method. According to this model, a part of the earth's crust covering the crystalline basement is considered as a set of many prisms located nearby. The depth of the surface of the crystalline basement is calculated taking into account the change in density at the bottom of the low velocity zones of the upper part of the earth's crust and the dependence of the density difference on depth according to a quadratic law.
 For interpretation of the gravity anomalies in the Absheron, Shamakhy-Gobustan and Pricaspian-Guba regions, a sedimentary basin viewed as, a number of prisms placed in juxtaposition. The decrease of density contrast in sedimentary basins approximated by, a quadratic function. The contour map is sampled at 1160 equispaced points with 5 km interval. The depths to the interface separating sedimentary were calculated using a generalized computer program GR3DSTR for 3-D inversion of gravity data either for a constant density contrast or for a variable density contrast with depth.
 From 3D gravity model of the sedimentary layer, it was found that the maximum depth is in the areas of Gyuzdek and Meraza (11 km), and the minimum is in the areas of Gonakkend, Gilazi, Garabulag, Dubrar (4 km).
 The depth of the sedimentary layer around the Agzibirchala well varies within 6 km. The correlation of the distribution of the thickness of the sedimentary layer on the site with the seismic section and well sections was determined.
 KEYWORDS – gravity anomaly, sedimentary basin, oil and gas fields.

Anomaly diagnosis of connected autonomous vehicles: A survey

Connected autonomous vehicles (CAVs) are revolutionizing the development of transportation due to their potential to improve transportation performance in many ways, such as enhanced traffic mobility, road compacity, operation safety, and environmental sustainability. Nevertheless, the issue of road vehicle safety in CAVs remains to be fully solved. Data collected from multiple sources provide information about the internal status of the system and the situation of its surroundings, and the occurrence of data anomalies indicates the existence of potential safety risks. Thus, anomaly diagnosis is of major importance to analyze the nature or cause of underlying safety risks and provide insightful information for the subsequent decision-making that ensures safety. Anomaly diagnosis consists of two basic tasks: anomaly detection and anomaly interpretation. In this paper, both of these two tasks are comprehensively surveyed. For anomaly detection, the following four aspects are covered: 1) formalized definition of an anomaly, 2) classification of anomalies, 3) taxonomies of anomaly detection techniques, and 4) review of recent advances for anomaly detection in CAV applications. For anomaly interpretation, related works are investigated in the context of 1) the anomaly detection process, and 2) the tested/monitored system/process, respectively. The novelty particularly lies in the latter, where the interpretation of anomalies combining the analysis of road vehicle safety risks is presented, and related works for anomaly interpretation in CAV applications are reviewed by analyzing 1) functional safety risks, 2) safety of the intended functionality (SOTIF) risks, and 3) cyber security risks, respectively. Finally, open issues, challenges, future directions, and emerging technologies for anomaly diagnosis in CAVs are discussed.

Structural and tectonic features of the Transcarpathian trough according to gravity and magnetic data

Based on the analysis and interpretation of gravity and magnetic field anomalies, we studiedthe peculiarities of fault tectonics, structural-tectonic structure (including salt dome tectonics) of the Transcarpathian trough. We identified signs of the manifestation of deep faults and other large structural-tectonic elements in anomalies of gravity and magnetic fields. We then traced these structural-tectonic units by comparing the morphology, intensity, dimensions, and directions of the typical anomalous zones in the gravitational and magnetic fields with the tectonic structure of the region.
 We used digital maps of gravitational and magnetic fields; averaging transforms and relief-shadow images, we mapped local gravimagnetic anomalies. Analysis of the spatial structure of the original gravimagnetic fields and their transforms and structural-tectonic maps yielded a reflection of large tectonic elements of fault tectonics, anticlinal and salt dome structures in the gravimagnetic fields. Based on gravimagnetic data, the tectonic structure of the Transcarpathian trough was clarified, and the boundaries of tectonic zones and microplates were traced. The zone of the Transcarpathian deep fault is identified as a tectonic zone traced by a band of intense local positive anomalies of the gravity field along the Flysch Carpathians to the border of the Marmarosh massif. It is limited by high gradients from the southwest and northeast and is a reflection of the Pieniny and Marmarosh rock zones. The zone of the Transcarpathian deep fault is considered a suture zone of the Inner and Flysch Carpathians. In the structure of the anomalous gravity field of the Transcarpathian trough, a number of local anomalies associated with salt stocks, as well as individual anomalies, expected to be connected to salt-bearing deposits, werefound.
 We confirmed the effectiveness of gravimagnetic methods in the geological conditions of the Transcarpathian trough to detect anticlinal structures, basement protrusions, which create favorable conditions for oil and gas traps in sedimentary strata. Interpreting anomalous gravimagnetic fields in combination with geological and tectonic materials is an important condition for the integral process of studying the geological and tectonic structure of the Earth’s crust in the Transcarpathian region.

Reconstructing subglacial lake activity with an altimetry-based inverse method

Abstract Subglacial lake water-volume changes produce ice-elevation anomalies that provide clues about water flow beneath glaciers and ice sheets. Significant challenges remain in the quantitative interpretation of these elevation-change anomalies because the surface expression of subglacial lake activity depends on basal conditions, rate of water-volume change, and ice rheology. To address these challenges, we introduce an inverse method that reconstructs subglacial lake activity from altimetry data while accounting for the effects of viscous ice flow. We use a linearized approximation of a Stokes ice-flow model under the assumption that subglacial lake activity only induces small perturbations relative to a reference ice-flow state. We validate this assumption by accurately reconstructing lake activity from synthetic data that are produced with a fully nonlinear model. We then apply the method to estimate the water-volume changes of several active subglacial lakes in Antarctica by inverting data from NASA's Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) laser altimetry mission. The results show that there can be substantial discrepancies (20% or more) between the inversion and traditional estimation methods due to the effects of viscous ice flow. The inverse method will help refine estimates of subglacial water transport and further constrain the role of subglacial hydrology in ice-sheet evolution.

Edge enhancement of potential field data using the enhanced gradient (EG) filter

Potential field data play a critical role in interpreting various geologic structural features through edge detection filters that aid in mapping subsurface structural features. For this purpose, various filters have been introduced in recent years to determine lateral boundaries. However, each of these filters has its limitations and advantages. This study presents a new edge enhancement filter named “Enhanced Gradient (EG)” based on the Richards function and applies it to potential field data for structural mapping. The EG is tested on two dimensional (2D) and three dimensional (3D) synthetic magnetic models with sources buried at different depths and variable properties. The results from the EG filter provide more accurate and higher resolution horizontal boundaries and can avoid creating the false edges in the output results. In addition, the proposed filter was examined using aeromagnetic data from the Indiana region in the USA. The primary and secondary faults and geological formations are recognizable in the EG image. The results of the EG map will allow us to improve the qualitative interpretation of potential field anomalies in studying the structural and tectonic geology of the Indiana region in the USA.

Magnetic anomaly interpretation for a 2D fault-like geologic structures utilizing the global particle swarm method

We establish a method to interpret the magnetic anomaly due to 2D fault structures, with an evaluation of first moving average residual anomalies utilizing filters of increasing window lengths. After that, the buried fault parameters are estimated using the global particle swarm method. The goodness of fit among the observed and the calculated models is expressed as the root mean squared (RMS) error. The importance of studying and delineating the fault parameters, which include the amplitude factor, the depth to the upper edge, the depth to the lower edge, the fault dip angle, and the position of the origin of the fault, is: (i) solving many problem-related engineering and environmental applications, (ii) describing the accompanying mineralized zones with faults, (iii) describing geological deformation events, (iv) monitoring the subsurface shear zones, (v) defining the environmental effects of the faults before organizing any investments, and (vi) imaging subsurface faults for different scientific studies.Finally, we show the method applied to two theoretical models including the influence of the regional background and the multi-fault effect and to real field examples from Australia and Turkey. Available geologic and geophysical information corroborates our interpretations.

Lithospheric Structure and Extensional Style of the Red Sea Rift Segments

Abstract The Red Sea provides an opportunity to study the processes during the transition from continental rifting to early-stage seafloor spreading during ocean initiation. We delineate variations of lithospheric architecture and the nature of extension along the Red Sea region through joint interpretation of gravity and geoid anomalies and gravity-topography transfer functions. We use lithospheric-scale models to compare stretching factors with upper mantle gravity anomaly, residual mantle Bouguer anomaly, and effective elastic thickness. Based on our observations, the Red Sea is divided into four segments; each having distinct lithospheric characteristics and stretching styles. These are: (i) southernmost Red Sea and Danakil having regionally weak and stretched lithosphere, (ii) southern Red Sea with fully developed seafloor spreading and asymmetric lithospheric architecture, (iii) central Red Sea having discontinuous magma accretion with newly formed seafloor spreading, and (iv) northern Red sea with a stronger lithosphere and limited stretching revealing a stage of continental rifting. In these segments, lithospheric stretching correlates with regions of weak lithosphere, including a regime of sublithospheric plume channel beneath the southern Red Sea. The Zabargad fracture zone between the central and northern segments is revealed as a major lithosphere-scale boundary that may act as a barrier to the propagation of seafloor spreading into the northern Red Sea. The weak and highly stretched lithosphere in this region may indicate the onset of a new spreading cell. Our results conclude that the evolution of the Red Sea is more complex than the previously suggested kinematic models of simple “unzipping” and illustrate that several extensional styles can exist within different segments during the initial stages of ocean formation.

Inversion of Geomagnetic Anomalies Caused by Ore Masses Using Hunger Games Search Algorithm

AbstractGeomagnetic anomaly interpretation through inversion procedures often yields useful results in determining the key details of ore masses. However, the problem is complicated due to the known ambiguous phenomena of the inversion process. Thus, details such as location, depth and shape can only be estimated using an efficient algorithm. To this end, we presented here a novel global optimization algorithm called Hunger Games Search (HGS) for the inversion of geomagnetic anomalies caused by ore masses. HGS is a well‐organized metaheuristic inspired by the hunger‐driven instincts and social behavioral decisions of animals. This is the first work in the literature to introduce this optimizer for the inversion of geophysical anomalies. We revealed the model parameter dependencies and the optimum control parameter values of the algorithm by performing some modal analyses and parameter tuning studies, respectively. The capability of HGS was demonstrated on synthetically produced geomagnetic responses and on three real anomalies obtained from some exploration fields in India and the USA. Uncertainty appraisal studies showed the solidity of the outputs of the algorithm. Moreover, some comparative studies with the fine‐tuned standard Particle Swarm Optimization, a commonly used tool for the inversion of geophysical anomalies, indicated that HGS algorithm provides better results in terms of convergence characteristics and solution stabilities in the presented inverse problem. We therefore recommend the use of this metaheuristic in model parameter estimation studies when dealing with this kind of geophysical potential field problems.

Lithosphere density structure of southeastern South America sedimentary basins from the analysis of residual gravity anomalies

We conduct a gravity study of the lithosphere beneath three large sedimentary basins in southeastern South America: Paraná, Chaco-Paraná, and Pantanal. We compile a massive gravity database and estimate the free-air and Bouguer gravity anomalies, resulting in a novel complete Bouguer anomaly map for the study area. To discern the influence of crustal loads with known lithologies, including sediments, basalts, and topography variations of the Moho discontinuity, we calculate their gravity effects and subsequently remove them from the complete Bouguer anomaly, leading to the development of our residual Bouguer anomaly map. This map highlights unknown anomalous masses within the lithosphere. To aid in the interpretation of these residual anomalies, we perform a 2D forward modeling. Based on our results, we propose new boundaries for the Paranapanema block and the Luiz Alves craton. Additionally, we propose that the Ponta Grossa swarm dike has a more substantial impact on the crust and lithosphere than previously considered, and delimit the region of influence of this magmatism in the lithosphere. Moreover, tectonic features such as the São Francisco paleocontinent and the Rio de La Plata craton appear to be associated with negative residual Bouguer anomaly regions. Furthermore, we identify and emphasize the significance of the Western Paraná Suture, which acts as a demarcation between the Paraná Basin region and the Pantanal and Chaco-Paraná basins. Remarkably, this suture appears to play a more important role in shaping the density structure of the southwest of South America than the age and tectonic history of the sedimentary basins.