Gamma-ray spectrometric evaluation in watersheds with gold anomalies in stream sediments, Passo Feio Complex, Caçapava do Sul region (Brazil)

This study utilizes gamma-ray spectrometry to identify source areas of gold recognized in geochemical prospecting work in stream sediments. The local geological context is represented by the Passo Feio Metamorphic Complex, which contains gold deposits possibly hosted in quartz veins concordant with...

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Bibliographic Details
Published in:Discover Geoscience Vol. 3; no. 1; pp. 58 - 13
Main Authors: Alves, Luiza Lima, Moreira, César Augusto, da Silva Araújo, Ana Flávia, Ilha, Lenon Melo, de Oliveira, João Pedro Prado, Kumaira, Sissa, Hansen, Marco Antonio Fontoura, Masquelin, Henri
Format: Journal Article
Language:English
Published: Cham Springer International Publishing 05.06.2025
Springer Nature B.V
Springer
Subjects:
Basins
Biogeosciences
Data processing
Earth and Environmental Science
Earth Sciences
Gamma rays
Gamma-ray spectrometry
Geochemistry
Geology
Geophysics
Geophysics/Geodesy
Geotechnical Engineering & Applied Earth Sciences
Gold
Gold mines & mining
Mineral exploration
Mineralization
Minerals
Quartz
River valleys
Scientific imaging
Sediments
Spectrometry
Veins (geology)
Water analysis
Brazil
Gold
Gamma-ray spectrometry
Mineral exploration
Geophysics
ISSN:2948-1589, 2948-1589
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Summary:This study utilizes gamma-ray spectrometry to identify source areas of gold recognized in geochemical prospecting work in stream sediments. The local geological context is represented by the Passo Feio Metamorphic Complex, which contains gold deposits possibly hosted in quartz veins concordant with metamorphic foliation, composed of quartzites, schists, and amphibolites. The study followed the sequence: geological reconnaissance, drone survey, and gamma-ray spectrometric acquisition. Field reconnaissance indicated an alternation of rocks oriented in a WNW/ENE direction, with recognition of quartz veins embedded concordantly with the foliation of quartzites. The drone data enabled the generation of a Digital Elevation Model (DEM) and served as a basis for planning the gamma-ray spectrometry work. A total of 715 gamma-ray spectrometric readings were taken, with an average spacing of 40 m between points, followed by data processing and the generation of maps of K (0.5–2.5%) concentrations, eU (0.9–3.9 ppm), and eTh (2.8–24.4 ppm). The data obtained regarding the K (%) concentration values reveal a clear anomaly in the central region with WNW/ENE orientation. The concentration data obtained for U (ppm) and Th (ppm) show a similar pattern concerning the WNW/ENE anomaly in the center of the area. The overlap of positive anomalies served as an indication of gold source areas in two river valleys. The combination of detailed gamma-ray spectrometry and precision digital terrain modeling has enabled the delineation of primary targets potentially mineralized in gold, in a versatile and fast way, compared to traditional soil sampling techniques.
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ISSN:2948-1589
2948-1589
DOI:10.1007/s44288-025-00170-1