Invited conference presentations
Design useful tools that do one thing well and work together: rediscovering the UNIX philosophy while building the Fatiando a Terra project
2021. Uieda, L, Li, L, Soler, SR, Pesce, A
AGU Fall Meeting
Note: This is an invited presentation about the past, current, and future of the Fatiando a Terra project. We will cover the current functionality, recent developments, and lessons learned along the way. The presentation is centered around a tutorial that walks you through the steps of transforming observed absolute gravity measurements into a grid of residual gravity disturbances at a constant height. The tutorial showcases some of the core utilities of all of our open-source libraries. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
The Fatiando a Terra project (https://www.fatiando.org) was started in 2010 as a Python library for visualization, forward modelling, and inversion across different geophysical methods. Over the following 8 years, the project attracted new contributors and grew to include cutting-edge methods, toy examples for teaching, and helper functions for visualization. Standards around testing, documentation, and code style evolved and new tools appeared around the ecosystem (such as SimPEG, PyVista, Devito, and pyGIMLi), making some of our functionality redundant and outdated. In an attempt to better interface with the emerging ecosystem, we started a major restructuring of the code base in 2018. This presentation will cover the current available functionality and some of the lessons learned from developing, growing, and maintaining the project, including current challenges and our future plans.
Python-based workflows for small-to-medium sized data: what works, what doesn't, and what can be improved
2021. Uieda, L, Soler, SR
AGU Fall Meeting
Note: This is an invited talk for the first part of an "Open Scince in Action" session, with 10 minute talks by panelists followed by a panel discussion. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
In this presentation, we will demonstrate the workflow that we have been establishing at the Computer-Oriented Geoscience Lab for building "repro-packs" for our papers and projects. We use a combination of virtual environments, data download and caching tools, notebooks, Makefiles, and data repositories to provide others with the means to reproduce and build upon our work. We will also share some of the unsolved challenges that we have encountered and our dreams for an ideal workflow.
Nurturing reliable and robust open-source scientific software
2017. Uieda, L, Wessel, P
AGU Fall Meeting
Note: I was invited to this panel session on Open-Source Software in the Geosciences along with Kerry Key, Brian Savage, Gary D Egbert, Colin Andrew Zelt, and Lion Krischer. Many thanks to the chairs Lindsey Heagy, Anna Kelbert and Louise Pellerin for putting this together.
Abstract
Scientific results are increasingly the product of software. The reproducibility and validity of published results cannot be ensured without access to the source code of the software used to produce them. Therefore, the code itself is a fundamental part of the methodology and must be published along with the results. With such a reliance on software, it is troubling that most scientists do not receive formal training in software development. Tools such as version control, continuous integration, and automated testing are routinely used in industry to ensure the correctness and robustness of software. However, many scientist do not even know of their existence (although efforts like Software Carpentry are having an impact on this issue). Publishing the source code is only the first step in creating an open-source project. For a project to grow it must provide documentation, participation guidelines, and a welcoming environment for new contributors. Expanding the project community is often more challenging than the technical aspects of software development. Maintainers must invest time to enforce the rules of the project and to onboard new members, which can be difficult to justify in the context of the “publish or perish” mentality. This problem will continue as long as software contributions are not recognized as valid scholarship by hiring and tenure committees. Furthermore, there are still unsolved problems in providing attribution for software contributions. Many journals and metrics of academic productivity do not recognize citations to sources other than traditional publications. Thus, some authors choose to publish an article about the software and use it as a citation marker. One issue with this approach is that updating the reference to include new contributors involves writing and publishing a new article. A better approach would be to cite a permanent archive of individual versions of the source code in services such as Zenodo. However, citations to these sources are not always recognized when computing citation metrics. In summary, the widespread development of reliable and robust open-source software relies on the creation of formal training programs in software development best practices and the recognition of software as a valid form of scholarship.
Department seminars
Open-science for gravimetry: tools, challenges, and opportunities
2021. Uieda, L, Soler, SR, Pesce, A
GFZ Helmholtz Centre Potsdam, Germany
Fatiando a Terra: Open-source tools for geophysics
2021. Uieda, L, Soler, SR, Pesce, A
Geophysical Society of Houston
Note: This was an invited talk to the Potential Fields group of the GSH. Thank you to Andrea Balza Morales for the invitation and for organizing the seminar series. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
The Fatiando a Terra project is a collection of open-source Python libraries for geophysics which cover a range of functionalities, from data download and processing to modeling and inversion. In this opportunity we will present the two libraries that are focused on potential fields: Harmonica and Boule. Boule implements reference ellipsoids (including oblate ellipsoids, spheres, and soon triaxial ellipsoids), conversions between ellipsoidal and geocentric spherical coordinates, and normal gravity calculations. The latter are performed using analytical expressions for gravity fields at any point outside of the ellipsoid. Harmonica provides tools for processing, forward modelling, and inversion of gravity and magnetic data. We will demonstrate its use to compute Bouguer gravity disturbances by forward modelling the topography with prisms, removing a 2nd order regional trend, and interpolating it onto a regular grid at a constant height using the equivalent layer technique. Both libraries are still evolving as we continue to refine their goals and scopes. We invite everyone to get involved in the development, whether it's through coding, writing documentation, or giving feedback.
Geophysical research powered by open-source
2020. Uieda, L
Christian-Albrechts-Universität zu Kiel, Germany
Note: I've given this talk at a few places in 2020 with some modifications to the slides. This is a presentation about my path through geophysics and open-source software, how it's shaped my research and teaching, what I see as the future of this area (with some tips for informing yourself on current software best practices), and some of the research we're doing at the Computer-Oriented Geoscience Lab. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
This was another online version of the talk. It was really nice to connect with the geophysicists at Kiel since Prof. Jörg Ebbing's group uses Tesseroids and was involved in the generation of the GOCE gravity gradient grids cited in the talk. They have also used the Moho inversion code and are getting involved in Fatiando. I added some bits to the end about getting involved in open-source software projects and finding online communities of practice (with a shout out to the Software Underground).
Geophysical research powered by open-source
2020. Uieda, L
Universidade de São Paulo, Brazil
Note: I've given this talk at a few places in 2020 with some modifications to the slides. This is a presentation about my path through geophysics and open-source software, how it's shaped my research and teaching, what I see as the future of this area (with some tips for informing yourself on current software best practices), and some of the research we're doing at the Computer-Oriented Geoscience Lab. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
I was really delighted to get an invitation to speak at my alma mater
(roughly 10 years after my graduation). The talk was also delivered
online. This was the first time delivering this talk in Portuguese, which
was a struggle since I had the words prepared in English already (slides
are still in English, though). I added the latest news of the successful
reproduction of the Ferguson COVID-19 modelling results. Funny enough,
this talk is heavily inspired on the last talk I gave there in 2015.
Geophysical research powered by open-source
2020. Uieda, L
Technische Universität Bergakademie Freiberg, Germany
Note: I've given this talk at a few places in 2020 with some modifications to the slides. This is a presentation about my path through geophysics and open-source software, how it's shaped my research and teaching, what I see as the future of this area (with some tips for informing yourself on current software best practices), and some of the research we're doing at the Computer-Oriented Geoscience Lab. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
This is the second version of this talk and it was delivered online because of the COVID-19 pandemic. I changed it a bit to reflect current research presented at EGU2020 and focus less on the technical side of development. The online delivery was new to me but it worked out well. Even though it can be strange to talk to a screen for 50 minutes, the great questions afterwards more than made up for it.
Geophysical research powered by open-source
2020. Uieda, L
Geographic Data Science Lab, University of Liverpool
Note: I've given this talk at a few places in 2020 with some modifications to the slides. This is a presentation about my path through geophysics and open-source software, how it's shaped my research and teaching, what I see as the future of this area (with some tips for informing yourself on current software best practices), and some of the research we're doing at the Computer-Oriented Geoscience Lab. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
This is the first version of this talk, delivered at the GDSL group
seminars. It was about my path through geophysics guided by my interests
in making open-source software: how I got started with coding, the various
projects I'm developing, how that's shaped my research, and plans for the
future.
Building the foundations for open-source geophysics
2019. Uieda, L
Department of Earth, Ocean and Ecological Sciences, University of Liverpool
Machine learning lessons for geophysics
2018. Uieda, L
Department of Earth Sciences, University of Hawai‘i at Mānoa
Inverting gravity to map the Moho: A new method and the open source software that made it possible
2017. Uieda, L
Department of Geology and Geophysics, University of Hawai‘i at Mānoa
Fatiando a Terra: construindo uma base para ensino e pesquisa de geofísica
2016. Uieda, L
Universidade de São Paulo • Observatório Nacional
Conference presentations
Harmonica and Boule: Modern Python tools for geophysical gravimetry
2021. Uieda, L, Soler, SR, Pesce, A, Perozzi, L, Wieczorek, MA
EGU General Assembly
doi:10.5194/egusphere-egu21-8291
Poster

Abstract
Gravimetry is a routine part of the geophysicists toolset, historically used in geophysics following the geodetic definitions of gravity anomalies and their related “reductions”. Several authors have shown that the geodetic concept of a gravity anomaly does not align with goals of gravimetry in geophysics (the investigation of anomalous density distributions). Much of this confusion likely stems from the lack of widely available tools for performing the corrections needed to arrive at a geophysically meaningful gravity disturbance. For example, free-air corrections are completely unnecessary since analytical expressions for theoretical gravity at any point have existed for over a decade. Since this is not easily done in a spreadsheet or short script, modern tools for processing and modelling gravity data for geophysics are needed. These tools must be trustworthy (i.e., extensively tested) and designed with software development and geophysical best practices in mind. We present the Python libraries Harmonica and Boule, which are part of the Fatiando a Terra project. Both tools are open-source under the permissive BSD license and are developed in the open by a community of geoscientists and programmers. Harmonica provides tools for processing, forward modelling, and inversion of gravity and magnetic data. The first release of Harmonica was focused on implementing methods for processing and interpolation with the equivalent source technique, as well as forward modelling with right-rectangular prisms, point sources, and tesseroids. Current work is directed towards implementing a processing pipeline for gravity data, including topographic corrections in Cartesian and spherical coordinates, atmospheric corrections, and more. The software is still in early stages of development and design and would benefit greatly from community involvement and feedback. Boule implements reference ellipsoids (including oblate ellipsoids, spheres, and soon triaxial ellipsoids), conversions between ellipsoidal and geocentric spherical coordinates, and normal gravity calculations using analytical solutions for gravity fields at any point outside of the ellipsoid. It includes ellipsoids for the Earth as well as other planetary bodies in the solar system, like Mars, the Moon, Venus, and Mercury. This enables the calculation of gravity disturbances for Earth and planetary data without the need for free-air corrections. Boule was created out of the shared needs of Harmonica, SHTools, and pygeoid and is developed with input from developers of these projects. We welcome participation from the wider geophysical community, irrespective of programming skill level and experience, and are actively searching for interested developers and users to get involved in shaping the future of these projects.
Citations
Evaluating the accuracy of equivalent-source predictions using cross-validation
2020. Uieda, L, Soler, SR
EGU General Assembly
doi:10.5194/egusphere-egu2020-15729
Note: Presented at EGU 2020 (online because of COVID-19), session G4.3: Acquisition and processing of gravity and magnetic field data and their integrative interpretation. Details some of the work we've been doing in Verde and Harmonica for machine-learning style interpolation with equivalent-sources. In particular, applying state-of-the-art cross-validation strategies to estimate interpolation accuracy and tune equivalent-source parameters.
Abstract
We investigate the use of cross-validation (CV) techniques to estimate the accuracy of equivalent-source (also known as equivalent-layer) models for interpolation and processing of potential-field data. Our preliminary results indicate that some common CV algorithms (e.g., random permutations and k-folds) tend to overestimate the accuracy. We have found that blocked CV methods, where the data are split along spatial blocks instead of randomly, provide more conservative and realistic accuracy estimates. Beyond evaluating an equivalent-source model's performance, cross-validation can be used to automatically determine configuration parameters, like source depth and amount of regularization, that maximize prediction accuracy and avoid over-fitting. Widely used in gravity and magnetic data processing, the equivalent-source technique consists of a linear model (usually point sources) used to predict the observed field at arbitrary locations. Upward-continuation, interpolation, gradient calculations, leveling, and reduction-to-the-pole can be performed simultaneously by using the model to make predictions (i.e., forward modelling). Likewise, the use of linear models to make predictions is the backbone of many machine learning (ML) applications. The predictive performance of ML models is usually evaluated through cross-validation, in which the data are split (usually randomly) into a training set and a validation set. Models are fit on the training set and their predictions are evaluated using the validation set using a goodness-of-fit metric, like the mean square error or the R² coefficient of determination. Many cross-validation methods exist in the literature, varying in how the data are split and how this process is repeated. Prior research from the statistical modelling of ecological data suggests that prediction accuracy is usually overestimated by traditional CV methods when the data are spatially auto-correlated. This issue can be mitigated by splitting the data along spatial blocks rather than randomly. We conducted experiments on synthetic gravity data to investigate the use of traditional and blocked CV methods in equivalent-source interpolation. We found that the overestimation problem also occurs and that more conservative accuracy estimates are obtained when applying blocked versions of random permutations and k-fold. Further studies need to be conducted to generalize these findings to upward-continuation, reduction-to-the-pole, and derivative calculation. Open-source software implementations of the equivalent-source and blocked cross-validation (in progress) methods are available in the Python libraries Harmonica and Verde, which are part of the Fatiando a Terra project.
Citations
Coupled interpolation of three-component GPS velocities
2018. Uieda, L, Xu, X, Wessel, P, Sandwell, DT
AGU Fall Meeting
Building an object-oriented Python interface for the Generic Mapping Tools
2018. Uieda, L, Wessel, P
SciPy 2018
Joint interpolation of 3-component GPS velocities constrained by elasticity
2018. Uieda, L, Sandwell, DT, Wessel, P
AOGS 15th Annual Meeting
Integrating the Generic Mapping Tools with the Scientific Python ecosystem
2018. Uieda, L, Wessel, P
AOGS 15th Annual Meeting
Using Fatiando a Terra to solve inverse problems in geophysics
2014. Uieda, L, Oliveira Jr, VC, Barbosa, VCF
SciPy 2014
Gravity inversion in spherical coordinates using tesseroids
2014. Uieda, L, Barbosa, VCF
EGU General Assembly
Modeling the Earth with Fatiando a Terra
2013. Uieda, L, Oliveira Jr, VC, Barbosa, VCF
SciPy 2013
doi:10.25080/Majora-8b375195-010
Note: This was the first presentation that I made about Fatiando a Terra, a Python library for modeling and inversion in geophysics. The proceedings paper that accompanies this talk became the second chapter of my PhD thesis.
Abstract
Solid Earth geophysics is the science of using physical observations of the Earth to infer its inner structure. Generally, this is done with a variety of numerical modeling techniques and inverse problems. The development of new algorithms usually involves copy and pasting of code, which leads to errors and poor code reuse. Added to this is a modeling pipeline composed of various tools that don't communicate with each other (Fortran/C for computations, large complicated I/O files, Matlab/VTK for visualization, etc). Fatiando a Terra is a Python library that aims to unify the modeling pipeline inside of the Python language. This allows users to replace the traditional shell scripting with more versatile and powerful Python scripting. Together with the new IPython notebook, Fatiando a Terra can integrate all stages of the geophysical modeling process, like data pre-processing, inversion, statistical analysis, and visualization. However, the library can also be used for quickly developing stand-alone programs that can be integrated into existing pipelines. Plus, because functions inside Fatiando a Terra use a common data and mesh format, existing algorithms can be combined and new ideas can build upon existing functionality. This flexibility facilitates reproducible computations, prototyping of new algorithms, and interactive teaching exercises. Although the project has so far focused on potential field methods (gravity and magnetics), some numerical tools for other geophysical methods have been developed as well. The library already contains: fast implementations of forward modeling algorithms (using Numpy and Cython), generic inverse problem solvers, unified geometry classes (prism meshes, polygons, etc), functions to automate repetitive plotting tasks with Matplotlib (automatic griding, simple GUIs, picking, projections, etc) and Mayavi (automatic conversion of geometry classes to VTK, drawing continents, etc). In the future, we plan to continuously implement classic and state-of-the-art algorithms as well as sample problems to help teach geophysics.
Citations
3D magnetic inversion by planting anomalous densities
2013. Uieda, L, Barbosa, VCF
AGU Meeting of the Americas
Iron ore interpretation using gravity-gradient inversions in the Carajás, Brazil
2012. Carlos, DU, Uieda, L, Li, Y, Barbosa, VCF, Braga, MA, Angeli, G, Peres, G
SEG Annual Meeting
Note: This presentation is about the work Dionisio U. Carlos did for his PhD. He used my planting inversion method on data from his research area in central Brazil. He couldn't make it to the meeting so I ended up giving the talk on his behalf.
Abstract
We have interpreted the airborne gravity gradiometry data from Carajás Mineral Province (CMP), Brazil, by using two different 3D inversion methods. Both inversion methods parameterized the Earth's subsurface into prismatic cells and estimate the 3D density-contrast distribution that retrieves an image of geologic sources subject to an acceptable data misfit. The first inversion method imposes smoothness on the solution by solving a linear system that minimizes an depth weighted L2 model objective function of density-contrast distribution. The second imposes compactness on the solution by using an iterative growth algorithm solved by a systematic search algorithm that accretes mass around user-specified prisms called “seeds”. Using these two inversion methods, the interpretation of full tensor gravity gradiometry data from an iron ore deposit in the area named N1 at CMP shows the consistent geometry and the depth of iron orebody. To date, the maximum depth of the iron orebody is assumed to be 200 m based on the maximum depth attained by the deepest well drilled in this study area. However, both inversion results exhibit a source whose maximum bottom depth is greater than 200 m. These results give rise two interpretations: i) the iron orebody may present its depth to the bottom greater than the maximum depth of 200 m attained by the deepest borehole; or ii) the iron orebody may be 200 m deep and the rocks below may be jaspilite whose density is close to that of soft hematite.
Citations
Use of the "shape-of-anomaly" data misfit in 3D inversion by planting anomalous densities
2012. Uieda, L, Barbosa, VCF
SEG Annual Meeting
Note: This talk is about an improvement to the method described in the paper "Robust 3D gravity gradient inversion by planting anomalous densities".
Abstract
We present an improvement to the method of 3D gravity gradient inversion by planting anomalous densities. This method estimates a density-contrast distribution defined on a grid of right-rectangular prisms. Instead of solving large equation systems, the method uses a systematic search algorithm to grow the solution, one prism at a time, around user-specified prisms called "seeds". These seeds have known density contrasts and the solution is constrained to be concentrated around the seeds as well as have their density contrasts. Thus, prior geologic and geophysical information are incorporated into the inverse problem through the seeds. However, this leads to a strong dependence of the solution on the correct location, density contrast, and number of seeds used. Our improvement to this method consists of using the "shape-of-anomaly" data-misfit function in conjunction with the l2-norm data-misfit function. The shape-of-anomaly function measures the different in shape between the observed and predicted data and is insensitive to differences in amplitude. Tests on synthetic and real data show that the improved method not only has an increased robustness with respect to the number of seeds and their locations, but also provides a better fit of the observed data.
Citations
Rapid 3D inversion of gravity and gravity gradient data to test geologic hypotheses
2012. Uieda, L, Barbosa, VCF
International Symposium on Gravity, Geoid and Height Systems
Robust 3D gravity gradient inversion by planting anomalous densities
2011. Uieda, L, Barbosa, VCF
SEG Annual Meeting
Note: This talk and expanded abstract present the second version of what would eventually become my first publication "Robust 3D gravity gradient inversion by planting anomalous densities" and Masters dissertation.
Abstract
We present a new gravity gradient inversion method for estimating a 3D density-contrast distribution defined on a grid of prisms. Our method consists of an iterative algorithm that does not require the solution of a large equation system. Instead, the solution grows systematically around user-specified prismatic elements called "seeds". Each seed can be assigned a different density contrast, allowing the interpretation of multiple bodies with different density contrasts and that produce interfering gravitational effects. The compactness of the solution around the seeds is imposed by means of a regularizing function. The solution grows by the accretion of neighboring prisms of the current solution. The prisms for the accretion are chosen by systematically searching the set of current neighboring prisms. Therefore, this approach allows that the columns of the Jacobian matrix be calculated on demand, which greatly reduces the demand of computer memory and processing time. Tests on synthetic data and on real data collected over an iron ore province of Quadrilátero Ferrífero, southeastern Brazil, confirmed the ability of our method in detecting sharp and compact bodies.
Citations
3D gravity inversion by planting anomalous densities
2011. Uieda, L, Barbosa, VCF
Internation Congress of the Brazilian Geophysical Society
Note: This talk and expanded abstract are a branch of my Masters degree research. It presents an adaptation of the gravity-gradient inversion to gravity data.
Abstract
This paper presents a novel gravity inversion method for estimating a 3D density-contrast distribution defined on a grid of prisms. Our method consists of an iterative algorithm that does not require the solution of a large equation system. Instead, the solution grows systematically around user-specified prismatic elements called "seeds". Each seed can have a different density contrast, allowing the interpretation of multiple bodies with different density contrasts and interfering gravitational effects. The compactness of the solution around the seeds is imposed by means of a regularizing function. The solution grows by the accretion of neighboring prisms of the current solution. The prisms for the accretion are chosen by systematically searching the set of current neighboring prisms. Therefore, this approach allows that the columns of the Jacobian matrix be calculated on demand. This is a known technique from computer science called "lazy evaluation", which greatly reduces the demand of computer memory and processing time. Test on synthetic data and on real data collected over the ultramafic Cana Brava complex, central Brazil, confirmed the ability of our method in detecting sharp and compact bodies.
Citations
Optimal forward calculation method of the Marussi tensor due to a geologic structure at GOCE height
2011. Uieda, L, Bomfim, EP, Braitenberg, C, Molina, E
4th International GOCE User Workshop
3D gravity gradient inversion by planting density anomalies
2011. Uieda, L, Barbosa, VCF
73th EAGE Conference and Exhibition incorporating SPE EUROPEC
doi:10.3997/2214-4609.20149567
Note: This poster and expanded abstract present the first version of what would be my first publication "Robust 3D gravity gradient inversion by planting anomalous densities" and eventually Masters dissertation.
Poster

Abstract
We present a new gravity gradient tensor inversion for estimating a 3D density-contrast distribution defined on a user-specified grid of prisms. Our method consists of an iterative algorithm that does not require the solution of large equation system. Instead, the solution grows systematically around user-specified prismatic elements called “seeds”. Each seed can have a different density contrast, allowing the interpretation of multiples bodies with different density contrasts. The compactness of the solution is imposed by means of a regularizing function that favors compact bodies closest to the priorly specified seeds. The solution grows by accreting neighboring prisms of the current solution. The prisms for the accretion are chosen by systematically searching the set of current neighboring prisms. Therefore, this approach allows that the columns of the Jacobian matrix be calculated on demand. This is a known technique from computer science called “lazy evaluation”, which greatly reduces the demand of computer memory and processing time. Test on synthetic data from multiple buried sources at different depths and on real data collected over iron deposits located in the Quadrilátero Ferrífero, southeastern region of Brazil, confirmed the ability of our method in detecting sharp and compact bodies.
Citations
Computation of the gravity gradient tensor due to topographic masses using tesseroids
2010. Uieda, L, Ussami, N, Braitenberg, C
AGU Meeting of the Americas
Other
Getting started with Open Science
2022. Uieda, L
SPIN-ITN workshop
Note: The slides were made with reveal.js using my open-source HTML talk template.
Abstract
Presentation for a short workshop about open science practices for the SPIN: Seismological Parameters and INstrumentation doctoral training network.
Academia e software livre: Desafios e oportunidades no Brasil e no exterior
2021. Uieda, L
National Observatory's SEG and EAGE Student Chapter, Brazil
Note: I had the pleasure of giving this talk to the SEG and EAGE Student Chapter of the Observatório Nacional (where I went to grad school). It was about my path through science and some tips for those wanting to go abroad. Slides and talk were in Portuguese. The slides were made with reveal.js using my open-source HTML talk template.
Abstract
Palestra e bate papo com o National Observatory Greenstone Belt (SEG-EAGE Student Chapter do Observatório Nacional) sobre minha carreira e dicas para os alunos que quiserem trilhar um caminho parecido.
Utilização de tesseróides na modelagem de dados de gradiometria gravimétrica
2008. Uieda, L, Ussami, N
XIII Simpósio de Iniciação Científica do IAG-USP
Paleomagnetismo e mineralogia magnética dos diques cambrianos de Maravilhas e Prata (PB)
2006. Uieda, L, D'Agrella-Filho, MS
XI Simpósio de Iniciação Científica do IAG-USP