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Scientific Investigations Report 2007-5191

Distribution of Igneous Rocks in Medina and Uvalde Counties, Texas, as Inferred from Aeromagnetic Data

David V. Smith, Robert R. McDougal, Bruce D. Smith, and Charles D. Blome

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Scientific Investigations Report
2007-5191 PDF (34 MB)

A high-resolution aeromagnetic survey was flown in 2001 over Medina and Uvalde Counties, Texas, as part of a multi-disciplinary investigation of the geohydrologic framework of the Edwards aquifer in south-central Texas. The objective of the survey was to assist in mapping structural features that influence aquifer recharge and ground-water flow. The survey revealed hundreds of magnetic anomalies associated with igneous rocks that had previously been unmapped. This report presents an interpretation of the outcrops and subcrops of igneous rocks, based upon procedures of matched-filtering and potential field modeling.

Version 1.0

Posted April 2008

Suggested citation:

Smith, D.V., McDougal, R.R., Smith, B.D., and Blome, C.D., 2008, Distribution of igneous rocks in Medina and Uvalde Counties, Texas, as inferred from aeromagnetic data: U.S. Geological Survey Scientific Investigations Report 2007–5191, 12 p., one plate, scale 1:250,000.



Geologic Setting

Data Processing


Summary and Conclusions

References Cited

Appendix. Georeferenced Igneous Rock Outlines in ESRI File Formats

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