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Geology topics

Isadore Zietz

Publications and source records attributed to Isadore Zietz.

7 recordsLinked to original sources
USGS2014

Magnetic anomalies at high altitudes

To investigate the effect of anomalies in the Earth's magnetic field at high altitudes , aeromagnetic maps of two representative areas showing isanomalic curves for total intensity are projected to levels of 10 and 20 miles above the surface of a plane Earth. The projections are accomplished by numerical computations and by use of a magnetic ‐field projecting machine at the Naval Ordnance Laboratory. It is found that anomalies of 500 gammas near the surface of the Earth, in merging into neighboring anomalies , may produce effects of 100 gammas or more at an altitude of 20 miles.

Eos, Transactions, American Geophysical Union↗
USGS1984

Truncation of the Appalachian Piedmont beneath the Coastal Plain of Alabama: Evidence from new magnetic data

A new aeromagnetic survey of a part of southern Alabama reveals that magnetic signatures of the Appalachian Piedmont are truncated by a major magnetic lineament beneath the Gulf Coastal Plain. Mylonitic rocks have been recovered from a drillhole along this lineament, which is probably a fault zone of late Paleozoic and/or Triassic-Jurassic age. We suggest that this fault zone may initially have been the Alleghanian convergent suture between the North American craton and accreted terranes to the southeast. The zone may have been locally reactivated as part of an extensive buried Triassic-Jurassic graben system.

North Carolina, South Carolina, Georgia. Mississip↗
USGS1959

A Summary interpretation of geologic, hydrologic, and geophysical data for Yucca Valley, Nevada test site, Nye County, Nevada

This report summarizes an interpretation of the geology of Yucca Valley to depths of about 2,300 feet below the surface, the characteristics features of ground water in Yucca and Frenchman Valleys, and the seismic, gravity, and magnetic data for these valleys. Compilation of data, preparation of illustrations, and writing of the report were completed during the period December 26, 1958 to January 10, 1959. Some of the general conclusions must be considered as tentative until more data are available. This work was done by the U.S. Geological Survey on behalf of Albuquerque Operations Office, U.S. Atomic Energy Commission.

Nevada↗
USGS1956

A preliminary report on model studies of magnetic anomalies of three-dimensional bodies

Model experiments were made to devise a rapid method for calculating magnetic anomalies of three-dimensional structures. The magnetic fields of the models were determined using the equipment at the Naval Ordnance Laboratory, White Oaks, Md. An irregularly shaped mass was approximated by an array of prismatic rectangular slabs of constant thickness and varying horizontal dimensions. Contoured maps are being prepared for these magnetic models at different depths and for several magnetic inclinations. The fields of these three-dimensional structures are obtained by superimposing the appropriate contoured maps and adding numerically the effects at each point. The equipment and laboratory methods are described. Theoretical and practical examples are given.

Geophysics↗
USGS1949

The computation of second vertical derivatives of geomagnetic fields

Second vertical derivatives of magnetic fields, because of their high resolving power, are often very useful in interpreting magnetic anomalies. Formulas are developed which permit their ready numerical computation. Comparisons are made between the resulting approximate values and the rigorous values obtained for simple idealized fields. The similarity between maps of second vertical derivatives of fields and those of certain types of residual fields is discussed.

Pennsylvania↗