Geology topics

R. G. Schmidt

Publications and source records attributed to R. G. Schmidt.

21 records · Page 2Linked to original sources

USGS1958

Bedrock geology of the southwestern part of the North Range, Cuyuna district, Minnesota

The Cuyuna manganiferous iron-ore district is in central Minnesota in Morrison, Crow Wing, and Aitkin Counties. The length of the district is about 68 miles, extending northeastward from a point near Randall, in Morrison County, to a point 11 miles east of the community of Hassmann in Aitkin County; the maximum known width is about 25 miles near the center of the district. Current mining activity is confined to a much smaller area, commonly called the North range, about 10 miles long and 3 miles wide near Crosby and Ironton in Crow Wing County. The average annual production of iron ore and manganiferous iron ore during 1940-50 was slightly less than 3 million tons.

Minnesota↗

USGS1957

Bedrock geology at the south-central part of the North Range, Cuyuna district, Minnesota

The Cuyuna iron-ore district is in central Minnesota in Morrison, Crow Wing, and Aitkin Counties. The length of the district is about 68 miles, extending from near Randall in Morrison County ot a point 11 miles east of the community of Hassmann in Aitkin County, and the maximum know width is about 25 miles near the center of the district. Current mining activity is confined to a much smaller area about 10 miles longs and 3 miles wide near Crosby and Ironton in Crow Wing County. This investigation has been restricted to the active area plus a marginal strip in which much exploratory drilling has been done. The average annual production of iron ore and manganiferous iron ore from the district during 1940-50 was slightly more than 3 million tons.

Minnesota↗

USGS1957

Geology of Saipan, Mariana Islands; Part 2, Petrology and soils

The rocks that comprise the volcanic formations of Saipan are of two principal types: dacites, which are characteristically glassy, and andesites, which are comparatively crystalline. The dacites consist primarily of silicic glass, oligoclase, and silica minerals (quartz, tridymite, cristobalite, chalcedony, and opal). Minor constituents in these rocks are green hornblende, biotite, magnetite, and hematite. The andesites are composed principally of labradorite, hypersthene, augite, and subcalcrc augite. Minor but also characteristic constituents of the andesites are quartz, tridymite, cristobalite, anorthoclase, and accessory magnetite, ilmenite, rutile, and apatite. Nine varieties of dacite and andesite are recognized on the basis of chemical composition, mineralogy, and texture. These are dacite, dacite vitrophyre, dacite perlite, hornblende-bearing dacite porphyry, augite-hypersthene andesite, quartz-bearing augite-hypersthene andesite, quartz-bearing augite-hypersthene andesite porphyry, augite andesite, and hypersthene andesite.

Professional Paper↗