Early geophysical papers of the Early geophysical papers of the Society of Exploration Geophysicists earlygeophysical00soci Year: 1947 8 W. P. JENNY The investigations were based on the measurements made by the surveys of the respective European states, and by the United States Coast and Geodetic Though by these studies a definite connection between broad structural features—such as the West Texas Permian basins, the Central Mineral region, the main geological trends in California and Europe—and magnetic anomalies of the vertical intensity could be definitely established, such studie
Early geophysical papers of the Early geophysical papers of the Society of Exploration Geophysicists earlygeophysical00soci Year: 1947 8 W. P. JENNY The investigations were based on the measurements made by the surveys of the respective European states, and by the United States Coast and Geodetic Though by these studies a definite connection between broad structural features—such as the West Texas Permian basins, the Central Mineral region, the main geological trends in California and Europe—and magnetic anomalies of the vertical intensity could be definitely established, such studies could only incidentally yield any information about the type of structure which is of special interest SCHEMATIC CR055 SECTION THROUGH TWO ANTICLINES 5HOWINC MACNCTiC LINES OF FORCE AND LOCAL AVACNETIC VECTORS |+ + + + | BOCK OF A(ORE THAN AVERAGE I I MACNCTIC PERmEABILITr ACNE TIE LINES OF FORCE TOTAL LOCAL VECTOR HORIZONTAL VECTOR VERTICAL VCCTOR l'\ NfXATIVE POLE POSITIVE VECTOR NEGATIVE VECTOR NEUTRAL VECTOR P05ITIVE POLE Fig. i to the commercial geologist, because the distances between the mag- netic stations, ranging from 20 to 50 miles, were far too large. It is quite evident that two, three, and more magnetic 'highs' and 'lows' may occur between stations placed at such distances and the lines of equal magnetic intensity, drawn on the base of such stations, as a rule veil, rather than set forth, the local magnetic anomalies which are due to small 'structures.' Study of Figure 1 will make the previous statement clear. This cross section through two anticlines separated by a syncline demon- strates schematically the paths of the magnetic lines of force and the 1 'United States Magnetic Tables and Magnetic Charts for 1925 by U. S. Depart- ment of Commerce,' U. S. Coast and Geodetic Survey Serial 453. 336
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