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Contributions of gamma‐ray spectrometry to terrestrial impact crater studies: The example of Serra da Cangalha, northeastern Brazil
Author(s) -
Vasconcelos Marcos Alberto R.,
Leite Emilson P.,
Crósta Alvaro P.
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl050525
Subject(s) - impact crater , geology , hydrothermal circulation , earth science , impact structure , geophysics , gamma ray spectrometry , geochemistry , mineralogy , astrobiology , paleontology , physics , chemistry , radiochemistry
Several geophysical methods have been used for decades for the identification and exploration of impact craters. Most of them are based on seismic, potential fields and electrical data, focusing on exploration of anomalies caused by changes in physical properties or by structures associated with the formation of the crater. Gamma‐ray spectrometry is usually not mentioned among the geophysical methods employed in crater studies, although it is known that impact cratering processes cause a number of physical/chemical changes in the country rocks. These changes include the remobilization of hydrothermal fluids which directly modify the composition of target rocks and, subsidiarily, of soils related to these rocks. Therefore, the distribution of radioactive elements K , Th and U has the potential to map such modifications. We present the analysis of gamma‐ray signatures at the Serra da Cangalha impact structure, located in northeastern Brazil, using methods for enhancing K anomalies and also the overall gamma‐ray signatures. These results provide valuable information on the distinct zones within the crater and might contribute to the understanding of hydrothermal enrichment processes produced as a result of the impact event.