An anomaly about 300 gammas in amplitude has been observed in data from an aerial magnetic survey flown over parts of Duval, Live Oak, McMullen, and Webb Counties, Tex. A two-and-one-half-dimensional model was used to iterpret the data, and the anomaly is apparently caused by a large mafic body centered near 28?10'N and 98?22'W, with an area of about 1800 km2 at a depth of 10 km.
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USGS Numbered Series
Interpretation of an aeromagnetic anomaly in McMullen and Live Oak counties, Texas