Research used information obtained from satellites to understand the context in which mineral deposits formed.
Research from Unicamp's Institute of Geosciences used satellite gravity data to reveal the extent of the Earth's crust formed billions of years ago in the Amazon. The study, carried out in the Carajás Mineral Province, aimed to understand the context in which certain types of deposits were formed and has important implications for the prospecting of copper deposits, a metal considered strategic due to its application in the current and future copper industry. eletric cars.
The study is part of the doctoral thesis of student João Gabriel Motta, a CNPq scholarship holder, in a project coordinated by Prof. Carlos Roberto de Souza Filho, also financed by CNPq. The work showed that the areas favorable for the existence of mineral deposits in that region are wider than previously imagined, which means an expansion of land that may contain as yet unknown copper deposits.
O article with the results obtained was published last Friday in the journal Scientific Reports, belonging to the group Nature, and was also authored by Professors Emmanuel John M. Carranza and Carla Braitenberg, respectively from the Universities of KwalaZulu-Natal (South Africa) and Trieste (Italy).
To carry out the analysis, the scientists used data from two satellite missions that were made available free of charge by Gravity Observation Combination Version 05 - a model representing Earth's gravity composed of information obtained by the European Space Agency (GOCE data) and by NASA and Space Agency German (GRACE data).
This data was processed to obtain the Complete Bouguer Anomaly - a product that allows the interpretation of the Earth's structure regarding the possible density of the materials present and their arrangement in the crust. Subsequently, the results were validated with the joint interpretation of magnetism and gravity data acquired by airborne platforms and terrestrial seismological studies, in addition to information on the crystallization age of the rocks and the material from which they are formed.
Results
The research revealed that the geological macro-structure of the studied region is more complex than anticipated. For example, the terrains located north of Carajás, although they present different characteristics from neighboring terrains from a surface perspective, share attributes at greater depth along the crust and in the lithospheric mantle. Based on these observations, the authors propose new limits for the land in the Carajás region, comparing 40 years of isotopic geology developed in that area.
“From a practical perspective, our evidence and interpretations made it possible to extend the favorable areas for the existence of copper deposits in the Carajás Mineral Province”, states João Motta.
originality
The authors explain that the innovation of the work was to integrate gravimetric and magnetometric data from various sources and validate observations extracted from orbital geophysical data, which are freely distributed and have global coverage. Orbital gravimetry, in particular, has revealed unprecedented geological information from the surface to great depths of the Earth's crust.
“Gravimetry is a tool generally used for geological exploration, but with terrestrial data or data acquired by airborne platforms. Although it has already been used to analyze regions that host mineral deposits, the results until then were limited and restricted to analyzes on a continental scale. Our study expanded this notion, focusing, perhaps for the first time, on the association between deep structures and mineral deposits, which have their traces at various scales”, says Prof. Carlos Roberto.
