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Geology topics

A. F. Buddington

Publications and source records attributed to A. F. Buddington.

At least 19 recordsLinked to original sources
USGS1963

Degree of oxidation of adirondack iron oxide and iron-titanium oxide minerals in relation to petrogeny

Partial chemical analyses of the accessory iron oxide and iron-titanium oxide minerals from more than one hundred samples of Adirondack igneous, metamorphic, and metasomatic rocks portray the degree of oxidation of the minerals and afford a basis for a discussion of their relation to the accompanying silicate assemblage and petrogeny. Among the granitic igneous rocks, the green pyroxenic facies have the least oxidized iron-titanium oxide minerals and a pink potassium-rich microperthitic microcline facies the most oxidized. Granites and syenites may crystallize with either an iron-rich variety of hornblende (or pyroxene) plus ilmenite, or with an iron-magnesium variety of hornblende (or of pyroxene) plus magnetite plus ilmenite, depending on the degree of oxidation. The granite facies of the orthogneisses of the Diana Complex (Precambrian) have a more oxidized mineral assemblage than the syenitic and quartz syenitic facies. The anorthosites and gabbro anorthosites have relatively oxygen-rich oxide minerals. Orthogneisses in the granulite facies have a lower ratio of Fe 2 O 3 /FeO than similar gneisses in the amphibolite facies. At least part of this lower ratio is due to metamorphism at higher temperatures and pressures. A regional belt of granitic orthogneiss metamorphosed in the amphibolite facies has a magnetite-sphene instead of a magnetite-ilmenite assemblage. Metasomatism of biotite-quartz-plagioclase gneiss to sillimanitic quartz-microcline gneisses is accompanied by decrease in mafic silicates and a series of changes of minerals in intermediate stages such that, in general, biotite yields with increasing degrees of oxidation successively such assemblages as (1) biotite, garnet, magnetite, hemo-ilmenite, and ilmeno-hematite; (2) pale brown mica, sillimanite, magnetite, and ilmeno-hematite; and (3) rutilo-hematite, rutile, and meagre silicates including sillimanite, muscovite, and chlorite. Diabase altered to monzodiorite by potassium-bearing solutions has ilmeno-magnetite partly altered to ilmeno-maghemite.

Journal of Petrology↗
USGS1959

Magnetostriction and palæomagnetism of igneous rocks

IN a recent communication, Stott and Stacey 1 report on a “crucial experiment” from which they conclude: “This excellent agreement between the dip and the directions of artificial thermoremanent magnetization of the stressed and unstressed rocks indicates that large systematic errors due to magnetostriction are most improbable in igneous rocks of types normally used for palæomagnetic work”. This experiment was intended to test the proposals 2 and measurements 3 bearing on the role of magnetostriction in rock magnetism. We present here our reasons for believing that the experiment was not crucial and that the conclusion is not justified.

Nature↗
USGS1958

Geology and magnetite deposits of Dover district, Morris County, New Jersey, with a description of the geologic section at Hibernia mine

The Dover district, Morris County, N. J., one of the oldest mining regions in the United States, has been active intermittently since the early part of the 18th century, and has yielded in excess of 26 million long tons of iron ore valued at more than $100,000,000. This is about 70 percent of the total production of iron ore from the State of New Jersey. Since 1940 about 500,000 tons of magnetite lump ore and fine concentrate have been shipped annually from the Scrub Oaks, Richard, and Mount Hope mines—the 3 producing mines in the district.

New Jersey↗