Geophysical Characterization of the Elk Creek Carbonatite (Southeastern Nebraska) using Joint Inversion of Airborne Gravity Gradiometry and Magnetic Data
Abstract
The Elk Creek Carbonatite Complex located in Southeastern Nebraska is a valuable mineral exploration target containing the largest known niobium deposit within the United States. It is an elliptical magmatic body formed in the early Paleozoic on the eastern margin of the Midcontinent Rift System. Airborne gravity gradiometry and magnetic surveys over the region identified niobium due to its strong aeromagnetic and gravity highs from the rest of the complex. In previous studies, the gravity and magnetic data were inverted separately resulting in density and magnetic susceptibility models that contained inconsistent features. We aim to better characterize the geological structure of the complex using joint inversion based on joint total variation (JTV). JTV enforces structural similarity between different physical property models and facilitates subsequent geological interpretation. Our preliminary results using synthetic data shows that joint inversion based on JTV offers significantly better results than single-data inversions, and compares favorably to other joint inversion methods. We are currently applying JTV joint inversion on the Elk Creek field data. Our goal is to build a 3D geology differentiation model that shows the spatial distribution of the geological units characterized by distinct ranges of density and magnetic susceptibility values. We are making use of an open source python inversion package, SimPEG, to develop our joint inversion framework which will be publicly accessible soon.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMNS43D0866L
- Keywords:
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- 0994 Instruments and techniques;
- EXPLORATION GEOPHYSICS;
- 0999 General or miscellaneous;
- EXPLORATION GEOPHYSICS;
- 1835 Hydrogeophysics;
- HYDROLOGY