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Gravity used to map lithology in granitic pluton

by Virginia Heffernan on September 15 applied

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Interpretation of gravity data at the area of granitic intrusions of the Moldanubian pluton near Kaplice. Image of gravity data over the Kaplice areas based on 1st vertical derivative Bouguer anomalies. 

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Physical and geological environment model generated in GM-SYS 2D, showing the potential of the geological structure of the Kaplice area.

An investigation of granitic intrusions in the southern Czech Republic was able to distinguish between individual rock types by processing and interpreting gravity data.

The area of study is the Moldanubian Pluton, part of a tectonic zone formed in central Europe 300-400 million years ago. The pluton is of interest to structural geologists because it contains intersecting granitic intrusions running in two different directions.

With the goal of using gravity to confirm the pluton’s geology, Anastasiia Melnyk, a Masters student in the geophysics department at Prague’s Charles University, processed data from gravimetric field measurements along the pluton using Geosoft’s Oasis montaj.

“Evaluation of the derived gravity data showed that the areas of increased gravity field gradient roughly correspond to the mapped geological interface” says Melnyk. “Therefore, I was able to distinguish individual rock types.”

Melnyk used Oasis montaj to integrate archival structural data with the new gravity measurements along two parallel 20 km profiles, giving her confidence in the correlation. The microlevelling extension enhanced her data and gave her a better handle on the geology of the area.

Melnyk first discovered Geosoft software when she took a course on 2D modelling of gravity and magnetic data using GM-SYS. She was inspired to learn more about data interpretation and geological modeling, choosing the Moldanubian Pluton as the topic of her thesis with the help of her supervisor.

It didn’t take her long to learn the basics of the program and she continues to master new features on an almost daily basis using web tutorials.

Geosoft’s education program offers educators, researchers and students affordable access to the latest technology, including comprehensive online support and learning resources. For more information, go to: http://www.geosoft.com/education-program.


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