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Maps showing aeromagnetic data and interpretation of the Medford 1 degree by 2 degrees Quadrangle, Oregon-California

January 1, 1994

These maps are part of a folio of maps of the Medford 1o x 2o quadrangle, Oregon, prepared under the Conterminous United States Mineral Assessment Program. Other publications in this folio discuss the geology, geophysics, geochemistry, and mineral assessment of the Medford 1o x 2o quadrangle and are listed in the references at the end of this report. 

The distinctive magnetic properties of the major rock types of the Medford 1o x 2o quadrangle over produce explicit magnetic anomalies. For example, contacts between magnetic ophiolitic rocks with nonmagnetic sedimentary rocks cause abrupt aeromagnetic boundaries even though these contacts may be buried at some depth below the topographic surface. Careful study of the aeromagnetic data, therefore, can provide insights about the geology and the mineral resource potential below the mapped surface. For example, aeromagnetic data may indicate the presence of an ultramafic body at shallow depth that is connected to an ultramafic outcrop with known chromite deposits.