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Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon

In tropical regions like the Amazon, there are extensive lateritic covers that have not been properly mapped, despite their economic-bearing minerals and their importance related to denudation and regolith landscape studies. To consolidate tools for regolith cartography, geochemical and geophysica...

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Main Authors: Iza, E. R. H. F., Horbe, Adriana Maria Coimbra, Castro, C. C., Herrera, I. L. I. E.
Format: Artigo
Language: Inglês
Published: American Geophysical Union 2019
Subjects:
Geoquímica
Geofísica
Amazônia - Brasil
Online Access: https://repositorio.unb.br/handle/10482/35900
https://doi.org/10.1029/2017GC007352
http://orcid.org/0000-0002-9152-4816
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spelling ir-10482-359002019-11-29T15:27:12Z Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon Iza, E. R. H. F. Horbe, Adriana Maria Coimbra Castro, C. C. Herrera, I. L. I. E. Geoquímica Geofísica Amazônia - Brasil In tropical regions like the Amazon, there are extensive lateritic covers that have not been properly mapped, despite their economic-bearing minerals and their importance related to denudation and regolith landscape studies. To consolidate tools for regolith cartography, geochemical and geophysical data (airborne gamma ray spectrometry and magnetometry) were integrated. Regional indexes (including the weathering intensity index, WII; lateritic index, LI; and mafic index, MI) were generated and applied, which allowed for the identification of regolith properties. The WII highlighted areas with high weathering levels located between 149 and 300 m and between 500 and 627 m of altitude that are related to the lower planation surface and upper planation surfaces, respectively. The LI ratified the WII and highlighted areas with high Th/K and U/K ratios, associated with lateritic duricrusts. The correlation between LI and MI showed lateritic duricrusts related to mafic and felsic substrates, especially on altitudes below 300 m, which confirmed the geochemical data. All of these results lead to the reinterpretation of areas previously considered to be sedimentary as residuals associated with oxisols and lateritic duricrusts, and this allows us to propose that the regolith mapping techniques and model generation (weathering intensity and lateritic indexes) have a good level of reliability. 2019-11-29T14:33:26Z 2019-11-29T14:33:26Z 2018-09 Artigo Iza, E. R. H. F. et al. Integration of geochemical and geophysical data to characterize and map lateritic regolith: an example in the Brazilian Amazon. Geochemistry, Geophysics, Geosystems, v.19, n. 9, p. 3254–3271, set. 2018. DOI: https://doi.org/10.1029/2017GC007352. https://repositorio.unb.br/handle/10482/35900 https://doi.org/10.1029/2017GC007352 http://orcid.org/0000-0002-9152-4816 Inglês https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017GC007352 Acesso Restrito ©2018. American Geophysical Union. All Rights Reserved. American Geophysical Union
institution REPOSITORIO UNB
collection REPOSITORIO UNB
language Inglês
topic Geoquímica
Geofísica
Amazônia - Brasil
spellingShingle Geoquímica
Geofísica
Amazônia - Brasil
Iza, E. R. H. F.
Horbe, Adriana Maria Coimbra
Castro, C. C.
Herrera, I. L. I. E.
Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon
description In tropical regions like the Amazon, there are extensive lateritic covers that have not been properly mapped, despite their economic-bearing minerals and their importance related to denudation and regolith landscape studies. To consolidate tools for regolith cartography, geochemical and geophysical data (airborne gamma ray spectrometry and magnetometry) were integrated. Regional indexes (including the weathering intensity index, WII; lateritic index, LI; and mafic index, MI) were generated and applied, which allowed for the identification of regolith properties. The WII highlighted areas with high weathering levels located between 149 and 300 m and between 500 and 627 m of altitude that are related to the lower planation surface and upper planation surfaces, respectively. The LI ratified the WII and highlighted areas with high Th/K and U/K ratios, associated with lateritic duricrusts. The correlation between LI and MI showed lateritic duricrusts related to mafic and felsic substrates, especially on altitudes below 300 m, which confirmed the geochemical data. All of these results lead to the reinterpretation of areas previously considered to be sedimentary as residuals associated with oxisols and lateritic duricrusts, and this allows us to propose that the regolith mapping techniques and model generation (weathering intensity and lateritic indexes) have a good level of reliability.
format Artigo
author Iza, E. R. H. F.
Horbe, Adriana Maria Coimbra
Castro, C. C.
Herrera, I. L. I. E.
author_sort Iza, E. R. H. F.
title Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon
title_short Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon
title_full Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon
title_fullStr Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon
title_full_unstemmed Integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the Brazilian Amazon
title_sort integration of geochemical and geophysical data to characterize and map lateritic regolith : an example in the brazilian amazon
publisher American Geophysical Union
publishDate 2019
url https://repositorio.unb.br/handle/10482/35900
https://doi.org/10.1029/2017GC007352
http://orcid.org/0000-0002-9152-4816
_version_ 1672205617541939200
score 13.657419

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