Integration of geophysical information with geological cartography for mineral resources research and other applications in Colombia: examples from the Serranía de San Lucas, Antioquia Batholith and eastern Amazonia
DOI:
https://doi.org/10.32685/0120-1425/bol.geol.48.Spl.1.2021.654Keywords:
airborne geophysics, gamma spectrometric data, magnetic data, chronostratigraphic units, ternary composition
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Copyright (c) 2022 Servicio Geológico Colombiano
This work is licensed under a Creative Commons Attribution 4.0 International License.
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Abstract
Airborne geophysical information is used in the interpretation of geological features. The variations observed in airborne magnetic and gamma spectrometric data are used mainly to support the differentiation of geological units, to delimitate structures and to define compositional/lithological changes. In this context, the objective of this study is to support geological mapping through airborne magnetometry and gamma spectrometry geophysical data. Examples from two regions of the Colombian territory: a) the Serranía de San Lucas-Antioqueño Batholith and b) eastern Colombia are presented. Gamma spectrometric data are used to generate images of the K, U and Th channels in a ternary (RGB false color) map for the purpose of delimitate geological-geophysical domains. The magnetometry information was processed to highlight anomalous magnetic features and provide information about the structural framework of each of the areas of interest.
In the Serranía de San Lucas and Antioquia Batholith areas, 27 gamma spectrometric domains were interpreted primarily from the ternary composition images. Within these domains, a good correlation with each of the chronostratigraphic units was observed, which enabled the identification and delimitation of areas with high or low concentrations of radioelements. In addition, the correlation of magnetic domains with high and low magnetic intensities and textures showed contrasts between igneous rocks, metamorphic rocks and sedimentary rocks. In the eastern zone, due to its fairly generalized geology, the geophysical information gained from both gamma spectrometry and magnetometry serves as a support to refine and delimitate the present geological units as well as their structural framework.
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