Geology topics

Patrick Taylor

Publications and source records attributed to Patrick Taylor.

3 recordsLinked to original sources

USGS2016

Rare earths: Market disruption, innovation, and global supply chains

Rare earths, sometimes called the vitamins of modern materials, captured public attention when their prices increased more than ten-fold in 2010 and 2011. As prices fell between 2011 and 2016, rare earths receded from public view—but less visibly they became a major focus of innovative activity in companies, government laboratories and universities. Geoscientists worked to better understand the resource base and improve our knowledge about mineral deposits that will be mines in the future. Process engineers carried out research that is making primary production and recycling more efficient. Materials scientists and engineers searched for substitutes that will require fewer or no rare earths while providing properties comparable or superior to those of existing materials. As a result, even though global supply chains are not significantly different now than they were before the market disruption, the innovative activity motivated by the disruption likely will have far-reaching, if unpredictable, consequences for supply chains of rare earths in the future.

Environment and Resources↗

USGS1971

Investigation of magnetization and density of a north Atlantic seamount using Poisson's theorem

The relationship between the gravitational and magnetic potentials caused by a uniform distribution of mass and magnetization may be used to obtain independent information about these physical properties. The general relationship in the frequency domain between the Fourier transforms of the gravity and magnetic anomaly fields is established through the Poisson theorem. The discrete Fourier transforms of the sampled continuous functions are used in an analysis which leads to a system of linear equations involving terms in density, magnetization, and calculated finite Fourier-series coefficients. A least squares solution of the system yields the three components of the total magnetization vector divided by the density. From these results, the direction of total magnetization and the minimum of the Koenigsberger ratio Q can be determined uniquely. The remanent magnetization direction and certain other information can be derived for special cases in which the value of one or more of the physical property terms can be assigned. Accurate results were obtained in the analysis of data from a theoretical model. Analysis of gravity and magnetic data from the North Atlantic Gilliss seamount indicates the presence of a significant component of remanent magnetization and leads to derived physical properties which are in fairly close agreement with dredged sample data. The calculated direction of remanent magnetization indicates a paleomagnetic pole position in eastern Siberia, in general agreement with the predicted position for a Cretaceous source in the North Atlantic. The seamount example illustrates certain contingent problems to be considered in practical application of the method.

Atlantic Ocean, Gilliss seamount↗

USGS1968

Geologic implications of aeromagnetic data for the eastern continental margin of the United States

An aeromagnetic survey extending from the Gulf of Maine to the tip of Florida was conducted by the U. S. Naval Oceanographic Office between 1964 and 1966. Flight traverses were flown in a northwesterly direction at right angles to the geologic grain. The flight lines were approximately 800 km long and had an 8-km separation. The survey traversed part of the New England, Piedmont, and Coastal Plain provinces and extended some 320 km beyond the continental shelf into the Atlantic Ocean. Despite the wide flight-line spacing, numerous geological and structural features became apparent from this survey. Interpretation of these features was aided by using the available gravity and seismic data in addition to the State and Provincial geologic maps. The residual aeromagnetic map shows a continuous magnetic high on or near the continental slope as far south as the 31st parallel. At about the 36th parallel, this east-coast magnetic anomaly splits into two branches, and both of them parallel the 850-fathom contour. At the 31st parallel, the outer branch of the anomaly swings westward and crosses the coastline near Brunswick, Georgia. This continuous magnetic anomaly may result from an igneous intrusive body that parallels the edge of the pre-Paleozoic continental landmass. These magnetic data suggest that Florida and part of Georgia were added to the paleo-continent in pre-Paleozoic time. Landward from the east-coast anomaly, the magnetic field is quite variable, whereas oceanward it has an extremely small gradient. The absence of magnetic anomalies east of the continental slope suggests that in this region layer 2 may be composed of metamorphosed basalt. The characteristic magnetic patterns observed over the Piedmont and New England provinces extend oceanward to the east-coast anomaly.

Eastern United States↗